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Presents a letter to the editor in response to the article "A Computed Method for Noninvasive MRI Assessment of Pulmonary Arterial Hypertension," by Eric Laffon, Christophe Vallet, Virginie Bernard, Michel Montaudon, Dominique Ducassou, François Laurent and Roger Marthan published in the August 2003 issue.

Chronic thromboembolic pulmonary hypertension (CTEPH) and idiopathic pulmonary arterial hypertension (iPAH) are both associated with right ventricular (RV) failure and mortality. However, CTEPH patients are older, more often male and usually have more co-morbidities than iPAH patients, including a history of venous thromboembolism. Therefore, RV adaptation to pressure-overload in CTEPH may be different than in iPAH. We included all treatment-naive CTEPH and iPAH patients diagnosed in the Amsterdam UMC between 2000 and 2019 if cardiac magnetic resonance imaging (CMR) and a right heart catheterization were performed at time of diagnosis. Load-dependent RV volumes and mass were assessed with CMR. Load-independent RV contractility, afterload and diastolic stiffness in relation to afterload were obtained using single beat pressure-volume loop analysis. Differences in RV characteristics between CTEPH and iPAH were analyzed using multiple linear regression with interaction testing after correcting for confounders. We included 235 patients in this study and performed pressure-volume loop analysis in 136 patients. In addition to being older and more often male, CTEPH patients had a lower pulmonary vascular resistance than iPAH patients at the time of diagnosis. After correcting for these confounders, CTEPH patients had a somewhat higher RV end-diastolic volume index (87 ± 27 ml vs 82 ± 25 ml; p <.01), and a lower RV relative wall thickness (0.6 ± 0,1 g/ml vs 0.7 ± 0,2 g/ml; p <.01). The correlation coefficient of RV diastolic stiffness to afterload was higher in CTEPH compared to iPAH (p <.05; independent of age and gender). Despite differences in patient characteristics, disease etiology and physiology, RV functional parameters in CTEPH and iPAH are mostly similar. The right ventricle in CTEPH is marginally more dilated, stiffer and less hypertrophic than in iPAH. [ABSTRACT FROM AUTHOR]

Objectives: To assess (I) correlations between diffusion-weighted (DWI), intravoxel incoherent motion (IVIM), dynamic contrast-enhanced (DCE) MRI, and 18F-FDG-PET/CT imaging parameters capturing tumor characteristics and (II) their predictive value of locoregional recurrence-free survival (LRFS) and overall survival (OS) in patients with head and neck squamous cell carcinoma (HNSCC) treated with (chemo)radiotherapy. Methods: Between 2014 and 2018, patients with histopathologically proven HNSCC, planned for curative (chemo) radiotherapy, were prospectively included. Pretreatment clinical, anatomical, and functional imaging parameters (obtained by DWI/IVIM, DCE-MRI, and 18F-FDG-PET/CT) were extracted for primary tumors (PT) and lymph node metastases. Correlations and differences between parameters were assessed. The predictive value of LRFS and OS was assessed, performing univariable, multivariable Cox and CoxBoost regression analyses. Results: In total, 70 patients were included. Significant correlations between 18F-FDG-PET parameters and DWI-/DCE volume parameters were found (r > 0.442, p < 0.002). The combination of HPV (HR = 0.903), intoxications (HR = 1.065), PT ADCGTV (HR = 1.252), Ktrans (HR = 1.223), and Ve (HR = 1.215) was predictive for LRFS (C-index = 0.546; p = 0.023). N-stage (HR = 1.058), HPV positivity (HR = 0.886), hypopharyngeal tumor location (HR = 1.111), ADCGTV (HR = 1.102), ADCmean (HR = 1.137), D* (HR = 0.862), Ktrans (HR = 1.106), Ve (HR = 1.195), SUVmax (HR = 1.094), and TLG (HR = 1.433) were predictive for OS (C-index = 0.664; p = 0.046). Conclusions: Functional imaging parameters, performing DWI/IVIM, DCE-MRI, and 18F-FDG-PET/CT, yielded complementary value in capturing tumor characteristics. More specific, intoxications, HPV-negative status, large tumor volume-related parameters, high permeability (Ktrans), and high extravascular extracellular space (Ve) parameters were predictive for adverse locoregional recurrence-free survival and adverse overall survival. Low cellularity (high ADC) and high metabolism (high SUV) were additionally predictive for decreased overall survival. These different predictive factors added to estimated locoregional and overall survival. Key Points: • Parameters of DWI/IVIM, DCE-MRI, and 18F-FDG-PET/CT were able to capture complementary tumor characteristics. • Multivariable analysis revealed that intoxications, HPV negativity, large tumor volume and high vascular permeability (Ktrans), and extravascular extracellular space (Ve) were complementary predictive for locoregional recurrence. • In addition to predictive parameters for locoregional recurrence, also high cellularity (low ADC) and high metabolism (high SUV) were complementary predictive for overall survival. [ABSTRACT FROM AUTHOR]

Between 16% and 51% of patients with chronic thromboembolic pulmonary hypertension will have residual pulmonary hypertension (PH) after pulmonary endarterectomy (PEA). Whether residual PH is related to remaining (sub-)segmental macrovascular lesions or to microvascular disease is unknown. New imaging techniques can provide detailed information about (sub-)segmental pulmonary arteries and parenchymal perfusion. The aim of this study was to describe the prevalence after PEA of remaining (sub-)segmental vascular lesions on electrocardiogram-gated computed tomography pulmonary angiography (CTPA) and parenchymal hypoperfusion on magnetic resonance imaging (MRI) and to relate these imaging abnormalities to the presence or absence of residual PH after PEA. In a prospective cohort of patients with operable chronic thromboembolic pulmonary hypertension, hemodynamics, CTPA, and lung perfusion MRI were performed before and 6 months after PEA. The percentage of (sub-)segmental vascular lesions was calculated on CTPA and parenchymal hypoperfusion on lung perfusion MRI. PEA led to significant improvements in hemodynamics and a reduction of imaging abnormalities. Residual PH was present in 45% of patients after PEA, whereas remaining (sub-)segmental vascular lesions and parenchymal hypoperfusion were present in 20% and 21% of the pulmonary vasculature, respectively. Patients with and without residual PH after PEA had similar percentages of remaining (sub-)segmental vascular lesions (25% ± 14% vs 17% ± 15%; p = 0.16) and similar degrees of parenchymal hypoperfusion (20% ± 7% vs 19% ± 6%; p = 0.63). After successful PEA, advanced imaging shows that around 20% of the pulmonary vasculature remains abnormal, independent of the presence of residual PH. This may suggest that microvascular disease, rather than residual macrovascular lesions, plays a prominent role in residual PH after PEA. [ABSTRACT FROM AUTHOR]

This systematic review gives an extensive overview of the current state of functional imaging during (chemo)radiotherapy to predict locoregional control (LRC) and overall survival (OS) for head and neck squamous cell carcinoma. MEDLINE and EMBASE were searched for literature until April 2018 assessing the predictive performance of functional imaging (computed tomography perfusion (CTp), MRI and positron-emission tomography (PET)) within 4 weeks after (chemo)radiotherapy initiation. Fifty-two studies (CTp: n = 4, MRI: n = 19, PET: n = 26, MRI/PET: n = 3) were included involving 1623 patients. Prognostic information was extracted according the PRISMA protocol. Pooled estimation and subgroup analyses were performed for comparable parameters and outcome. However, the heterogeneity of included studies limited the possibility for comparison. Early tumoral changes from (chemo)radiotherapy can be captured by functional MRI and 18F-FDG-PET and could allow for personalized treatment adaptation. Lesions showed potentially prognostic intratreatment changes in perfusion, diffusion and metabolic activity. Intratreatment ADCmean increase (decrease of diffusion restriction) and low SUVmax (persistent low or decrease of 18F-FDG uptake) were most predictive of LRC. Intratreatment persistent high or increase of perfusion on CT/MRI (i.e. blood flow, volume, permeability) also predicted LRC. Low SUVmax and total lesion glycolysis (TLG) predicted favorable OS. The optimal timing to perform functional imaging to predict LRC or OS was 2-3 weeks after treatment initiation. [ABSTRACT FROM AUTHOR]

Background/objectives Assessing atrial sizes by routine non-gated CT-angiography (CTA) could be of value in discriminating between pulmonary hypertension (PH) due to heart failure with preserved ejection fraction (HFpEF) and idiopathic pulmonary arterial hypertension (IPAH). We aimed to determine how left (LA) and right atrial (RA) sizes on non-gated CTA can help discriminate between these patients. Methods and results In an initial study, CMR was used in 15 IPAH and 15 PH-HFpEF patients to determine LA- and RA size throughout the cardiac cycle. While significant variations were noted in LA size over the cardiac cycle, the calculated ratio of left over right atrial size (LA/RA ratio) remained stable in both groups and discriminated between PH-HFpEF and IPAH. In a second study, routine non-gated CTA was used to validate the diagnostic use of a LA/RA ratio in 95 consecutive treatment-naive patients with a final diagnosis of either IPAH (n = 64) or PH-HFpEF (n = 31). ROC analyses were conducted to determine the discriminative properties of atrial size parameters. On a transversal view, LA size was 19 cm 2 (± 5) in the IPAH group versus 27 cm 2 (± 6) in the PH-HFpEF group ( p < 0.001). CTA derived LA/RA ratio was significantly higher in PH-HFpEF patients compared to IPAH patients and had good discriminative abilities (AUC = 0.833). Conclusions Assessing LA/RA size ratio by non-gated CTA allows for accurate discrimination between PH-HFpEF and IPAH patients. Because CTA is often available in the early diagnostic work-up, a LA/RA size ratio may guide clinical and diagnostic decision-making, even before invasive hemodynamic measurements. [ABSTRACT FROM AUTHOR]

The article attempts to determine the minimal important difference (MID) in stroke volume among patients with pulmonary hypertension (PH). According to the authors, stroke volume is arguably the best hemodynamic parameter because it reflects right ventricular function in response to its load. They report that in the experiment conducted, change in stroke volume was found to be correlated with the change in six-min walk test (6MWT). They conclude that a 10-mL change in stroke volume during follow-up can be considered as clinically relevant.

The article presents a study that investigates the ability of noninvasively assessed proximal pulmonary artery stiffness to assess relative area change (RAC) and predict mortality in patients with pulmonary arterial hypertension (PAH). There are 86 subjects who underwent right-heart catheterization and magnetic resonance imaging to assess area distensibility and RAC. It is concluded that noninvasively measured pulmonary artery RAC predicts mortality in patients with PAH.

Right ventricular (RV) afterload is commonly defined as pulmonary vascular resistance, but this does not reflect the afterload to pulsatile flow. The purpose of this study was to quantify RV afterload more completely in patients with and without pulmonary hypertension (PH) using a three-element windkessel model. The model consists of peripheral resistance (R), pulmonary arterial compliance (C), and characteristic impedance (Z). Using pulmonary artery pressure from right-heart catheterization and pulmonary artery flow from MRI velocity quantification, we estimated the windkessel parameters in patients with chronic thromboembolic PH (CTEPH; n = 10) and idiopathic pulmonary arterial hypertension (IPAH; n = 9). Patients suspected of PH but in whom PH was not found served as controls (NONPH; n = 10). R and Z were significantly lower and C significantly higher in the NONPH group than in both the CTEPH and IPAH groups (P < 0.001). R and Z were significantly lower in the CTEPH group than in the IPAH group (P < 0.05). The parameters R and C of all patients obeyed the relationship C = 0.75/R (R² = 0.77), equivalent to a similar RC time in all patients. Mean pulmonary artery pressure P and C fitted well to C = 69.7/P (i.e., similar pressure dependence in all patients). Our results show that differences in RV afterload among groups with different forms of PH can be quantified with a windkessel model. Furthermore, the data suggest that the RC time and the elastic properties of the large pulmonary arteries remain unchanged in PH. [ABSTRACT FROM AUTHOR]

The conventional gradient-echo steady-state signal model is the basis of various spoiled gradient-echo (SPGR) based quantitative MRI models, including variable flip angle (VFA) MRI and dynamic contrast-enhanced MRI (DCE). However, including preparation pulses, such as fat suppression or saturation bands, disrupts the steady-state and leads to a bias in T 1 and DCE parameter estimates. This work introduces a signal model that improves the accuracy of VFA T 1 -mapping and DCE for interrupted spoiled gradient-echo (I-SPGR) acquisitions. The proposed model was applied to a VFA T 1 -mapping I-SPGR sequence in the Gold Standard T 1 -phantom (3 T), in the brain of four healthy volunteers (3 T), and to an abdominal DCE examination (1.5 T). T 1 -values obtained with the proposed and conventional model were compared to reference T 1 -values. Bland-Altman analysis (phantom) and analysis of variance (in vivo) were used to test whether bias from both methods was significantly different (p = 0.05). The proposed model outperformed the conventional model by decreasing the bias in the phantom with respect to the phantom reference values (mean bias -2 vs. -35% at 3 T) and in vivo with respect to the conventional SPGR (-6 vs. -37% bias in T 1 , p < 0.01). The proposed signal model estimated approximately 48% (depending on baseline T 1 ) higher contrast concentrations in vivo, which resulted in decreased DCE pharmacokinetic parameter estimates of up to 35%. The proposed signal model improves the accuracy of quantitative parameter estimation from disrupted steady-state I-SPGR sequences. It therefore provides a flexible method for applying fat suppression, saturation bands, and other preparation pulses in VFA T 1 -mapping and DCE., (© 2024 The Author(s). NMR in Biomedicine published by John Wiley & Sons Ltd.)

Introduction: Pathogenic variants in the gene encoding for BMPR2 are a major genetic risk factor for heritable pulmonary arterial hypertension. Owing to incomplete penetrance, deep phenotyping of unaffected carriers of a pathogenic BMPR2 variant through multimodality screening may aid in early diagnosis and identify susceptibility traits for future development of pulmonary arterial hypertension., Methods: 28 unaffected carriers (44±16 years, 57% female) and 21 healthy controls (44±18 years, 48% female) underwent annual screening, including cardiac magnetic resonance imaging, transthoracic echocardiography, cardiopulmonary exercise testing and right heart catheterisation. Right ventricular pressure-volume loops were constructed to assess load-independent contractility and compared with a healthy control group. A transgenic Bmpr2 Δ71Ex1/+ rat model was employed to validate findings from humans., Results: Unaffected carriers had lower indexed right ventricular end-diastolic (79.5±17.6 mL·m -2 versus 62.7±15.3 mL·m -2 ; p=0.001), end-systolic (34.2±10.5 mL·m -2 versus 27.1±8.3 mL·m -2 ; p=0.014) and left ventricular end-diastolic (68.9±14.1 mL·m -2 versus 58.5±10.7 mL·m -2 ; p=0.007) volumes than control subjects. Bmpr2 Δ71Ex1/+ rats were also observed to have smaller cardiac volumes than wild-type rats. Pressure-volume loop analysis showed that unaffected carriers had significantly higher afterload (arterial elastance 0.15±0.06  versus 0.27±0.08 mmHg·mL -1 ; p<0.001) and end-systolic elastance (0.28±0.07  versus 0.35±0.10 mmHg·mL -1 ; p=0.047) in addition to lower right ventricular pulmonary artery coupling (end-systolic elastance/arterial elastance 2.24±1.03 versus 1.36±0.37; p=0.006). During the 4-year follow-up period, two unaffected carriers developed pulmonary arterial hypertension, with normal N-terminal pro-brain natriuretic peptide and transthoracic echocardiography indices at diagnosis., Conclusion: Unaffected BMPR2 mutation carriers have an altered cardiac phenotype mimicked in Bmpr2 Δ71Ex1/+ transgenic rats. Future efforts to establish an effective screening protocol for individuals at risk for developing pulmonary arterial hypertension warrant longer follow-up periods., Competing Interests: Conflicts of interest: F. Perros reports grants from French National Research Agency (ANR-20-CE14-0006) and INSERM (International Research Project (IRP) (Paris – Porto Pulmonary Hypertension Collaborative Laboratory (3PH)). D. Montani reports grants from Janssen, MSD and Acceleron; consultation fees from Janssen, MSD, Ferrer and Acceleron; and payment or honoraria for lectures, presentations, manuscript writing or educational events from Bayer, Janssen, Boehringer, Chiesi, GSK, Ferrer and Merck MSD. A. Vonk Nordegraaf reports research grants from Janssen, MSD and Ferrer. L. Zhao reports grants from British Heart Foundation (PG/18/2/33446 and BHF RE/18/4/34215). F.S. de Man reports support for the present study from Royal Netherlands Academy of Sciences (CVON-2017-10 Dolphin-Genesis); grants from Netherlands CardioVascular Research Initiative: the Dutch Heart Foundation, Dutch Federation of University Medical Centres, Netherlands Organisation for Health Research and Development, The Netherlands Organisation for Scientific Research (NWO-VICI: 918.16.610, NWO-VIDI: 917.18.338), Royal Netherlands Academy of Sciences (CVON-2012-08 PHAEDRA and CVON-2018-29 PHAEDRA-IMPACT) and Dutch Heart Foundation (Post doc Dekker 2018T05). H-J. Bogaard reports support for the present study from Royal Netherlands Academy of Sciences (CVON-2017-10 Dolphin-Genesis); grants from MSD, Ferrer, Janssen, Dutch Federation of University Medical Centres, Netherlands CardioVascular Research Initiative: the Dutch Heart Foundation, Netherlands Organisation for Health Research and Development, and the Royal Netherlands Academy of Sciences (CVON-2012-08 PHAEDRA and CVON-2018-29 PHAEDRA-IMPACT). The remaining authors have no potential conflicts of interest to disclose., (Copyright ©The authors 2024.)

Background: Measures that can detect large treatment effects are important for monitoring therapeutic effectiveness. The 2022 European Society of Cardiology/European Respiratory Society guidelines highlight the importance of imaging in monitoring disease status and treatment response in pulmonary arterial hypertension (PAH). Are the standardised treatment effect sizes (STES) of cardiac magnetic resonance imaging (cMRI) comparable with functional and haemodynamic variables?, Methods: REPAIR (ClinicalTrials.gov: NCT02310672) was a prospective, multicentre, single-arm, open-label, 52-week phase 4 study evaluating the effect of macitentan 10 mg, with or without a phosphodiesterase 5 inhibitor (PDE5i), on right ventricular (RV) remodelling, cardiac function and cardiopulmonary haemodynamics. Both cMRI and functional assessments were performed at screening and at weeks 26 and 52; haemodynamic measurements were conducted at screening and week 26. In this post hoc analysis, STES were estimated using the parametric Cohen's d and non-parametric Cliff's delta tests., Results: At week 26, large STES (Cohen's d) were observed for 10 of the 20 cMRI variables assessed, including the prognostic measures of RV and left ventricular stroke volume and RV ejection fraction and the haemodynamic trial end-point, pulmonary vascular resistance; medium STES were observed for 6-min walk distance (6MWD). The STES were consistent in treatment-naïve patients and those escalating therapy and maintained at week 52. Similar results were obtained using the non-parametric Cliff's delta method., Conclusions: The treatment effect of macitentan, alone or in combination with a PDE5i, was comparable for several cMRI and haemodynamic variables with prognostic value in PAH, and greater than that of 6MWD in patients with PAH, highlighting the emerging relevance of cMRI in PAH., Competing Interests: Conflict of interests: D.G. Kiely is a steering committee member for Janssen Pharmaceutical Companies of Johnson & Johnson, and receives grant/research support from Janssen Pharmaceutical Companies of Johnson & Johnson, Bayer and GlaxoSmithKline, in addition to other financial or material support, including consultancy and speaker fees, from Janssen Pharmaceutical Companies of Johnson & Johnson, Bayer, GlaxoSmithKline, Ferrer and MSD. Conflict of interests: R. Channick serves as a steering committee member, served on an advisory board, and received research grants/support and speaker fees from Janssen Pharmaceutical Companies of Johnson & Johnson; has served on an advisory board for Bayer; has received consultancy and speaker fees from Bayer and Arena Pharmaceuticals; and has received research grants from United Therapeutics. Conflict of interests: D. Flores is an employee of Janssen Pharmaceutical Companies of Johnson & Johnson. Conflict of interests: N. Galiè is a steering committee member for Janssen Pharmaceutical Companies of Johnson & Johnson; has received grant support, personal fees and non-financial support from Janssen Pharmaceutical Companies of Johnson & Johnson, and has received grant support and personal fees from Bayer Healthcare, Pfizer and GlaxoSmithKline. Conflict of interests: G. MacDonald is an employee of Janssen Pharmaceutical Companies of Johnson & Johnson. Conflict of interests: J.T. Marcus received consultancy fees from Janssen Pharmaceutical Companies of Johnson & Johnson. Conflict of interests: L. Mitchell is an employee of Janssen Pharmaceutical Companies of Johnson & Johnson. Conflict of interests: A. Peacock receives grant/research support from Janssen Pharmaceutical Companies of Johnson & Johnson, Bayer and GlaxoSmithKline, in addition to other financial or material support from Arena Pharmaceuticals Ltd and MSD. Conflict of interests: S. Rosenkranz has served as a steering committee member for Janssen Pharmaceutical Companies of Johnson & Johnson; has received research grants from AstraZeneca, Bayer, Janssen Pharmaceutical Companies of Johnson & Johnson and Novartis; has received speaker and/or consulting fees from and/or been an advisory board member for Abbott, Acceleron, Actelion, Aerovate, Altavant, AOP, Bayer, BMS, Boehringer-Ingelheim, Edwards, Ferrer, Gossamer, Janssen Pharmaceutical Companies of Johnson & Johnson, MSD, Novartis, Pfizer, UT and Vifor. Conflict of interests: A. Tawakol receives consultancy fees from Janssen Pharmaceutical Companies of Johnson & Johnson and Esperion, as well as grant/research support from Genentech. Conflict of interests: A. Torbicki receives consultancy fees from Janssen Pharmaceutical Companies of Johnson & Johnson, Arena Pharmaceuticals Ltd, Bayer, MSD, Pfizer and United Therapeutics, in addition to grant/research support from Janssen Pharmaceutical Companies of Johnson & Johnson, and speaker's bureau fees from Janssen Pharmaceutical Companies of Johnson & Johnson, AOP, Bayer, MSD and Pfizer; they are also an advisory board member for Janssen Pharmaceutical Companies of Johnson & Johnson. Conflict of interests: A. Vonk Noordegraaf receives ongoing grant/research support from Janssen Pharmaceutical Companies of Johnson & Johnson, GlaxoSmithKline and MSD, and speaker's bureau payments from Janssen Pharmaceutical Companies of Johnson & Johnson. Conflict of interests: A.J. Swift has received consultancy fees from Janssen Pharmaceutical Companies of Johnson & Johnson and General Electric Ltd, as well as grant support from GlaxoSmithKline., (Copyright ©The authors 2024.)

Background: The 2022 European Society of Cardiology/European Respiratory Society pulmonary hypertension (PH) guidelines incorporate cardiac magnetic resonance (CMR) imaging metrics in the risk stratification of patients with pulmonary arterial hypertension (PAH). Thresholds to identify patients at estimated 1-year mortality risks of < 5%, 5% to 20%, and > 20% are introduced. However, these cutoff values are mostly single center-based and require external validation., Research Question: What are the discriminative prognostic properties of the current CMR risk thresholds stratifying patients with PAH?, Study Design and Methods: We analyzed data from incident, treatment-naïve patients with PAH from the Amsterdam University Medical Centres, Vrije Universiteit, The Netherlands. The discriminative properties of the proposed CMR three risk strata were tested at baseline and first reassessment, using the following PH guideline variables: right ventricular ejection fraction, indexed right ventricular end-systolic volume, and indexed left ventricular stroke volume., Results: A total of 258 patients with PAH diagnosed between 2001 and 2022 fulfilled the study criteria and were included in this study. Of these, 172 had follow-up CMR imaging after 3 months to 1.5 years. According to the CMR three risk strata, most patients were classified at intermediate risk (n = 115 [45%]) upon diagnosis. Only 29 (11%) of patients with PAH were classified at low risk, and 114 (44%) were classified at high risk. Poor survival discrimination was seen between risk groups. Appropriate survival discrimination was seen at first reassessment., Interpretation: Risk stratifying patients with PAH with the recent proposed CMR cutoffs from the European Society of Cardiology/European Respiratory Society 2022 PH guidelines requires adjustment because post-processing consensus is lacking and general applicability is limited. Risk assessment at follow-up yielded better survival discrimination, emphasizing the importance of the individual treatment response., Competing Interests: Financial/Nonfinancial Disclosures The authors have reported to CHEST the following: H. J. B. and A. V. N. were supported by research grants from Actelion, GSK, and Ferrer (Therabel). None declared (L. R. C., J. N. W., J. T. M., L. J. M., F. S. d. M.)., (Copyright © 2023 The Author(s). Published by Elsevier Inc. All rights reserved.)

Objective: A 45% threshold of right ventricular ejection fraction (RVEF) is proposed clinically relevant in patients with pulmonary arterial hypertension (PAH). We aim to determine treatment response, long-term right ventricular (RV) functional stability and prognosis of patients with PAH reaching or maintaining the RVEF 45% threshold., Methods: Incident, treatment-naive, adult PAH patients with cardiac magnetic resonance imaging at baseline and first follow-up were included (total N=127) and followed until date of censoring or death/lung transplantation. Patients were categorised into two groups based on 45% RVEF. Baseline predictors, treatment response and prognosis were assessed with logistic regression analyses, two-way analysis of variance and log-rank tests., Results: Patients were 50±17 years old, 73% female, of which N=75 reached or maintained the 45% RVEF threshold at follow-up (RVEF≥45%@FU), while N=52 patients did not (RVEF<45%@FU). RV end-diastolic volume and N-terminal pro-B-type natriuretic peptide at baseline were multivariable predictors of an RVEF ≥45% at follow-up. A 40% pulmonary vascular resistance (PVR) reduction resulted in greater improvement in RV function (ΔRVEF 17±11 vs. 5±8; p interaction <0.001) compared to a PVR reduction <40%, but did not guarantee an RVEF ≥45%. Finally, the 45% RVEF threshold was associated with stable RV function during long-term follow-up and better survival (HR: 1.91 (95% CI: 1.11 to 3.27)). Patients failing to reach or maintain the 45% RVEF threshold at first follow-up mostly stayed below this threshold over the next consecutive visits., Conclusion: After treatment initiation, 60% of patients with PAH reach or maintain the 45% RVEF threshold, which is associated with a long-term stable RV function and favourable prognosis., Competing Interests: Competing interests: HJB and AVN were supported by research grants from Actelion, GSK and Ferrer (Therabel). The remaining authors have nothing to disclose., (© Author(s) (or their employer(s)) 2023. Re-use permitted under CC BY-NC. No commercial re-use. See rights and permissions. Published by BMJ.)

Background: Surgical removal of thromboembolic material by pulmonary endarterectomy (PEA) leads within months to the improvement of right ventricular (RV) function in the majority of patients with chronic thromboembolic pulmonary hypertension. However, RV mass does not always normalize. It is unknown whether incomplete reversal of RV remodeling results from extracellular matrix expansion (diffuse interstitial fibrosis) or cellular hypertrophy, and whether residual RV remodeling relates to altered diastolic function., Methods: We prospectively included 25 patients with chronic thromboembolic pulmonary hypertension treated with PEA. Structured follow-up measurements were performed before, and 6 and 18 months after PEA. With single beat pressure-volume loop analyses, we determined RV end-systolic elastance (Ees), arterial elastance (Ea), RV-arterial coupling (Ees/Ea), and RV end-diastolic elastance (stiffness, Eed). The extracellular volume fraction of the RV free wall was measured by cardiac magnetic resonance imaging and used to separate the myocardium into cellular and matrix volume. Circulating collagen biomarkers were analyzed to determine the contribution of collagen metabolism., Results: RV mass significantly decreased from 43±15 to 27±11g/m 2 (-15.9 g/m 2 [95% CI, -21.4 to -10.5]; P <0.0001) 6 months after PEA but did not normalize (28±9 versus 22±6 g/m 2 in healthy controls [95% CI, 2.1 to 9.8]; P <0.01). On the contrary, Eed normalized after PEA. Extracellular volume fraction in the right ventricular free wall increased after PEA from 31.0±3.8 to 33.6±3.5% (3.6% [95% CI, 1.2-6.1]; P =0.013) as a result of a larger reduction in cellular volume than in matrix volume ( P interaction =0.0013). Levels of MMP-1 (matrix metalloproteinase-1), TIMP-1 (tissue inhibitor of metalloproteinase-1), and TGF-β (transforming growth factor-β) were elevated at baseline and remained elevated post-PEA., Conclusions: Although cellular hypertrophy regresses and diastolic stiffness normalizes after PEA, a relative increase in extracellular volume remains. Incomplete regression of diffuse RV interstitial fibrosis after PEA is accompanied by elevated levels of circulating collagen biomarkers, suggestive of active collagen turnover., Competing Interests: Disclosures All authors certify that they have no affiliations with or involvement in any organization or entity with any financial interest (such as honoraria; educational grants; participation in speakers’ bureaus; membership, employment, consultancies, stock ownership, or other equity interest; and expert testimony or patent-licensing arrangements) or nonfinancial interest (such as personal or professional relationships, affiliations, knowledge, or beliefs) in the subject matter or materials discussed in this article.

Background: Precapillary pulmonary hypertension (precPH) patients have altered right atrial (RA) function and right ventricular (RV) diastolic stiffness., Objectives: This study aimed to investigate RA function using pressure-volume (PV) loops, isolated cardiomyocyte, and histological analyses., Methods: RA PV loops were constructed in control subjects (n = 9) and precPH patients (n = 27) using magnetic resonance and catheterization data. RA stiffness (pressure rise during atrial filling) and right atrioventricular coupling index (RA minimal volume / RV end-diastolic volume) were compared in a larger cohort of patients with moderate (n = 39) or severe (n = 41) RV diastolic stiffness. Cardiomyocytes were isolated from RA tissue collected from control subjects (n = 6) and precPH patients (n = 9) undergoing surgery. Autopsy material was collected from control subjects (n = 6) and precPH patients (n = 4) to study RA hypertrophy, capillarization, and fibrosis., Results: RA PV loops showed 3 RA cardiac phases (reservoir, passive emptying, and contraction) with dilatation and elevated pressure in precPH. PrecPH patients with severe RV diastolic stiffness had increased RA stiffness and worse right atrioventricular coupling index. Cardiomyocyte cross-sectional area was increased 2- to 3-fold in precPH, but active tension generated by the sarcomeres was unaltered. There was no increase in passive tension of the cardiomyocytes, but end-stage precPH showed reduced number of capillaries per mm 2 accompanied by interstitial and perivascular fibrosis., Conclusions: RA PV loops show increased RA stiffness and suggest atrioventricular uncoupling in patients with severe RV diastolic stiffness. Isolated RA cardiomyocytes of precPH patients are hypertrophied, without intrinsic sarcomeric changes. In end-stage precPH, reduced capillary density is accompanied by interstitial and perivascular fibrosis., Competing Interests: Funding Support and Author Disclosures Drs Bogaard, Vonk Noordegraaf, Goumans, and de Man were supported by the Netherlands CardioVascular Research Initiative: the Dutch Heart Foundation, Dutch Federation of University Medical Centres, the Netherlands Organisation for Health Research and Development, and the Royal Netherlands Academy of Sciences (CVON-2012-08 PHAEDRA, CVON-2018-29 PHAEDRA-IMPACT, and CVON-2017-10 Dolphin-Genesis). Drs Vonk Noordegraaf and de Man were further supported by the Netherlands Organization for Scientific Research (NWO-VICI: 918.16.610, NWO-VIDI: 917.18.338). Dr de Man was supported by a Dutch Heart Foundation Dekker senior postdoc grant (2018T059). Drs Bogaard and Vonk Noordegraaf have received research grant support from Actelion, GSK, and Ferrer (Therabel). Dr de Man has received research grant support from Janssen and BIAL. Dr Handoko has received consultancy/speaker fees from Novartis, Boehringer Ingelheim, AstraZeneca, Vifor, Bayer, MSD, and Abbott. All other authors have reported that they have no relationships relevant to the contents of this paper to disclose., (Copyright © 2023 The Authors. Published by Elsevier Inc. All rights reserved.)

Current diagnostic criteria for myelofibrosis are largely based on bone marrow (BM) biopsy results. However, these have several limitations, including sampling errors. Explorative studies have indicated that imaging might form an alternative for the evaluation of disease activity, but the heterogeneity in BM abnormalities complicates the choice for the optimal technique. In our prospective diagnostic pilot study, we aimed to visualize all BM abnormalities in myelofibrosis before and during ruxolitinib treatment using both PET/CT and MRI. A random sample of patients was scheduled for examinations at baseline and after 6 and 18 months of treatment, including clinical and laboratory examinations, BM biopsies, MRI (T1-weighted, Dixon, dynamic contrast-enhanced (DCE)) and PET/CT ([ 15 O]water, [ 18 F]NaF)). At baseline, all patients showed low BM fat content (indicated by T1-weighted MRI and Dixon), increased BM blood flow (as measured by [ 15 O]water PET/CT), and increased osteoblastic activity (reflected by increased skeletal [ 18 F]NaF uptake). One patient died after the baseline evaluation. In the others, BM fat content increased to various degrees during treatment. Normalization of BM blood flow (as reflected by [ 15 O]water PET/CT and DCE-MRI) occurred in one patient, who also showed the fastest clinical response. Vertebral [ 18 F]NaF uptake remained stable in all patients. In evaluable cases, histopathological parameters were not accurately reflected by imaging results. A case of sampling error was suspected. We conclude that imaging results can provide information on functional processes and disease distribution throughout the BM. Differences in early treatment responses were especially reflected by T1-weighted MRI. Limitations in the gold standard hampered the evaluation of diagnostic accuracy.

Background: Pulmonary arterial hypertension (PAH) patients have altered right atrial (RA) function and right ventricular (RV) diastolic stiffness. This study assessed the impact of RV diastolic stiffness on RA-RV interaction., Methods: PAH patients with low or high end-diastolic elastance (E ed ) (n=94) were compared with controls (n=31). Treatment response was evaluated in 62 patients. RV and RA longitudinal strain, RA emptying and RV filling were determined and diastole was divided into a passive and active phase. Vena cava backflow was calculated as RA active emptying-RV active filling and RA stroke work as RA active emptying×RV end-diastolic pressure., Results: With increased E ed , RA and RV passive strain were reduced while active strain was preserved. In comparison to controls, patients had lower RV passive filling but higher RA active emptying and RA stroke work. RV active filling was lower in patients with high E ed , resulting in higher vena cava backflow. Upon treatment, E ed was reduced in ~50% of the patients with high E ed , which coincided with larger reductions in afterload, RV mass and vena cava backflow and greater improvements in RV active filling and stroke volume in comparison with patients in whom E ed remained high., Conclusions: In PAH, RA function is associated with changes in RV function. Despite increased RA stroke work, severe RV diastolic stiffness is associated with reduced RV active filling and increased vena cava backflow. In 50% of patients with high baseline E ed , diastolic stiffness remained high, despite treatment. A reduction in E ed coincided with a large reduction in afterload, increased RV active filling and decreased vena cava backflow., Competing Interests: Conflict of interest: J.N. Wessels has nothing to disclose. Conflict of interest: S.A. Mouratoglou has nothing to disclose. Conflict of interest: J. van Wezenbeek has nothing to disclose. Conflict of interest: M.L. Handoko has nothing to disclose. Conflict of interest: J.T. Marcus has nothing to disclose. Conflict of interest: L.J. Meijboom has nothing to disclose. Conflict of interest: B.E. Westerhof has nothing to disclose. Conflict of interest: H.J. Bogaard was supported by research grants from Actelion, GSK and Ferrer (Therabel). Conflict of interest: G.J. Strijkers has nothing to disclose. Conflict of interest: A. Vonk Noordegraaf was supported by research grants from Actelion, GSK and Ferrer (Therabel). Conflict of interest: F.S. de Man has nothing to disclose., (Copyright ©The authors 2022.)

Right ventricular (RV) wall tension in pulmonary arterial hypertension (PAH) is determined not only by pressure, but also by RV volume. A larger volume at a given pressure generates more wall tension. Return of reflected waves early after the onset of contraction, when RV volume is larger, may augment RV load. We aimed to elucidate: (1) the distribution of arrival times of peak reflected waves in treatment-naïve PAH patients; (2) the relationship between time of arrival of reflected waves and RV morphology; and (3) the effect of PAH treatment on the arrival time of reflected waves. Wave separation analysis was conducted in 68 treatment-naïve PAH patients. In the treatment-naïve condition, 54% of patients had mid-systolic return of reflected waves (defined as 34-66% of systole). Despite similar pulmonary vascular resistance (PVR), patients with mid-systolic return had more pronounced RV hypertrophy compared to those with late-systolic or diastolic return (RV mass/body surface area; mid-systolic return 54.6 ± 12.6 g m -2 , late-systolic return 44.4 ± 10.1 g m -2 , diastolic return 42.8 ± 13.1 g m -2 ). Out of 68 patients, 43 patients were further examined after initial treatment. At follow-up, the stiffness of the proximal arteries, given as characteristic impedance, decreased from 0.12 to 0.08 mmHg s mL -1 . Wave speed was attenuated from 13.3 to 9.1 m s -1 , and the return of reflected waves was delayed from 64% to 71% of systole. In conclusion, reflected waves arrive at variable times in PAH. Early return of reflected waves was associated with more RV hypertrophy. PAH treatment not only decreased PVR, but also delayed the timing of reflected waves. KEY POINTS: Right ventricular (RV) wall tension in pulmonary arterial hypertension (PAH) is determined not only by pressure, but also by RV volume. Larger volume at a given pressure causes larger RV wall tension. Early return of reflected waves adds RV pressure in early systole, when RV volume is relatively large. Thus, early return of reflected waves may increase RV wall tension. Wave reflection can provide a description of RV load. In PAH, reflected waves arrive back at variable times. In over half of PAH patients, the RV is exposed to mid-systolic return of reflected waves. Mid-systolic return of reflected waves is related to RV hypertrophy. PAH treatment acts favourably on the RV not only by reducing resistance, but also by delaying the return of reflected waves. Arrival timing of reflected waves is an important parameter for understanding the relationship between RV load and its function in PAH., (© 2022 The Authors. The Journal of Physiology published by John Wiley & Sons Ltd on behalf of The Physiological Society.)

Background: To investigate the association between altered sex hormone expression and long-term right ventricular (RV) adaptation and progression of right heart failure in a Dutch cohort of Pulmonary Arterial Hypertension (PAH)-patients across a wide range of ages., Methods: In this study we included 279 PAH-patients, of which 169 females and 110 males. From 59 patients and 21 controls we collected plasma samples for sex hormone analysis. Right heart catheterization (RHC) and/or cardiac magnetic resonance (CMR) imaging was performed at baseline. For longitudinal data analysis, we selected patients that underwent a RHC and/or CMR maximally 1.5 years prior to an event (death or transplantation, N = 49)., Results: Dehydroepiandrosterone-sulfate (DHEA-S) levels were reduced in male and female PAH-patients compared to controls, whereas androstenedione and testosterone were only reduced in female patients. Interestingly, low DHEA-S and high testosterone levels were correlated to worse RV function in male patients only. Subsequently, we analyzed prognosis and RV adaptation in females stratified by age. Females ≤45years had best prognosis in comparison to females ≥55years and males. No differences in RV function at baseline were observed, despite higher pressure-overload in females ≤45years. Longitudinal data demonstrated a clear distinction in RV adaptation. Although females ≤45years had an event at a later time point, RV function was more impaired at end-stage disease., Conclusions: Sex hormones are differently associated with RV function in male and female PAH-patients. DHEA-S appeared to be lower in male and female PAH-patients. Females ≤45years could persevere pressure-overload for a longer time, but had a more severe RV phenotype at end-stage disease., (Copyright © 2021 The Authors. Published by Elsevier Inc. All rights reserved.)

Background: Heart failure with preserved ejection fraction (HFpEF) is a prevalent disorder for which no effective treatment yet exists. Pulmonary hypertension (PH) and right atrial (RA) and ventricular (RV) dysfunction are frequently observed. The question remains whether the PH with the associated RV/RA dysfunction in HFpEF are markers of disease severity., Methods: To obtain insight in the relative importance of pressure-overload and left-to-right interaction, we compared RA and RV function in 3 groups: 1. HFpEF (n=13); 2. HFpEF-PH (n=33), and; 3. pulmonary arterial hypertension (PAH) matched to pulmonary artery pressures of HFpEF-PH (PH limited to mPAP ≥30 and ≤50 mmHg) (n=47). Patients underwent right heart catheterization and cardiac magnetic resonance imaging., Results: The right ventricle in HFpEF-PH was less dilated and hypertrophied than in PAH. In addition, RV ejection fraction was more preserved (HFpEF-PH: 52±11 versus PAH: 36±12%). RV filling patterns differed: vena cava backflow during RA contraction was observed in PAH only. In HFpEF-PH, RA pressure was elevated throughout the cardiac cycle (HFpEF-PH: 10 [8-14] versus PAH: 7 [5-10] mm Hg), while RA volume was smaller, reflecting excessive RA stiffness (HFpEF-PH: 0.14 [0.10-0.17] versus PAH: 0.08 [0.06-0.11] mm Hg/mL). RA stiffness was associated with an increased eccentricity index (HFpEF-PH: 1.3±0.2 versus PAH: 1.2±0.1) and interatrial pressure gradient (9 [5 to 12] versus 2 [-2 to 5] mm Hg)., Conclusions: RV/RA function was less compromised in HFpEF-PH than in PAH, despite similar pressure-overload. Increased RA pressure and stiffness in HFpEF-PH were explained by left atrial/RA-interaction. Therefore, our results indicate that increased RA pressure is not a sign of overt RV failure but rather a reflection of HFpEF-severity.

Positive end-expiratory pressure (PEEP) is routinely applied in mechanically ventilated patients to improve gas exchange and respiratory mechanics by increasing end-expiratory lung volume (EELV). In a recent experimental study in rats, we demonstrated that prolonged application of PEEP causes diaphragm remodeling, especially longitudinal muscle fiber atrophy. This is of potential clinical importance, as the acute withdrawal of PEEP during ventilator weaning decreases EELV and thereby stretches the adapted, longitudinally atrophied diaphragm fibers to excessive sarcomere lengths, having a detrimental effect on force generation. Whether this series of events occurs in the human diaphragm is unknown. In the current study, we investigated if short-term application of PEEP affects diaphragm geometry and function, which are prerequisites for the development of longitudinal atrophy with prolonged PEEP application. Nineteen healthy volunteers were noninvasively ventilated with PEEP levels of 2, 5, 10, and 15 cmH 2 O. Magnetic resonance imaging was performed to investigate PEEP-induced changes in diaphragm geometry. Subjects were instrumented with nasogastric catheters to measure diaphragm neuromechanical efficiency (i.e., diaphragm pressure normalized to its electrical activity) during tidal breathing with different PEEP levels. We found that increasing PEEP from 2 to 15 cmH 2 O resulted in a caudal diaphragm displacement (19 [14-26] mm, P < 0.001), muscle shortening in the zones of apposition (20.6% anterior and 32.7% posterior, P < 0.001), increase in diaphragm thickness (36.4% [0.9%-44.1%], P < 0.001) and reduction in neuromechanical efficiency (48% [37.6%-56.6%], P < 0.001). These findings demonstrate that conditions required to develop longitudinal atrophy in the human diaphragm are present with the application of PEEP. NEW & NOTEWORTHY We demonstrate that PEEP causes changes in diaphragm geometry, especially muscle shortening, and decreases in vivo diaphragm contractile function. Thus, prerequisites for the development of diaphragm longitudinal muscle atrophy are present with the acute application of PEEP. Once confirmed in ventilated critically ill patients, this could provide a new mechanism for ventilator-induced diaphragm dysfunction and ventilator weaning failure in the intensive care unit (ICU).

Background: Drugs approved for pulmonary arterial hypertension have been considered for patients with heart failure with preserved ejection fraction and combined post- and precapillary pulmonary hypertension (Cpc-PH). We aimed to study changes in cardiac volumes, cardiac load and left ventricular (LV) filling pressures in patients with heart failure with preserved ejection fraction and Cpc-PH in response to pulmonary arterial hypertension-specific treatment., Methods and Results: In this prospective study, 23 patients with heart failure with preserved ejection fraction and Cpc-PH underwent right-heart catheterization, including acute provocation testing (fluid loading and inhaled nitric oxide) and cardiac MRI at baseline. Right-heart catheterization and cardiac MRI were repeated after 4 months of treatment. At baseline, acutely increasing preload by fluid loading resulted in a significant increase in pulmonary arterial wedge pressure (PAWP), whereas reducing right ventricular (RV) afterload and increasing LV distensability by acute administration of inhaled nitric oxide had no effect on PAWP. After 4 months of treatment, we observed a significant reduction in RV and LV afterload and increased RV and LV stroke volume, but PAWP significantly increased., Conclusions: In patients with heart failure with preserved ejection fraction and Cpc-PH, 4 months of pulmonary arterial hypertension-specific treatment increased RV and LV stroke volume at the expense of increased PAWP. This increase in PAWP was similarly observed acutely after fluid loading., (Copyright © 2019 Elsevier Inc. All rights reserved.)

Intravoxel incoherent motion (IVIM) imaging is increasingly applied in the assessment of head and neck cancer (HNC). Our purpose was to determine the diagnostic and prognostic performance of IVIM in HNC by performing a critical review of the literature. Pubmed and EMBASE were searched until May 2016. Study and patients characteristics, imaging protocol and diagnostic or prognostic outcomes were extracted by 2 independent reviewers. The studied IVIM parameters were diffusion coefficient (D), pseudodiffusion coefficient (D∗), and perfusion fraction (f). We included 10 diagnostic studies, 5 prognostic studies and 2 studies assessing both. Studies were very heterogeneous in terms of applied b-values, imaging protocols, outcome measurements and reference standards; therefore we did not perform a meta-analysis. The most commonly used sequence was "spin-echo planar imaging". A median of 10.5 b-values (range, 3-17) were used. All but three studies included at least 4 b-values below b=200s/mm 2 . By combining IVIM-parameters squamous cell carcinomas, lymphomas, malignant salivary gland tumors, Warthin's tumors and pleomorphic adenomas could be differentiated with a sensitivity of 85-87% and specificity of 80-100%. Low pre-treatment D or f and an increase in D during treatment were associated with a favorable response to treatment. D∗ appeared to be the parameter with the lowest prognostic value. Future research should focus on finding the optimal IVIM protocol, using uniformly accepted study methods and larger patient populations., (Copyright © 2017 The Author(s). Published by Elsevier Ltd.. All rights reserved.)

Background: Although cardiac magnetic resonance imaging (CMRI) is the gold standard for the (serial) assessment of right ventricular (RV) function, the technique has several drawbacks: CMRI is relatively expensive, has a limited availability, and the analyses are time consuming. Echocardiography (echo) can overcome several of these issues. The aim of this study was to compare simple echo-derived parameters of RV systolic function with CMRI-derived RV ejection fraction (RVEF) in patients with precapillary pulmonary hypertension (PH) and to determine which echo parameters best followed the change in CMRI-derived-RVEF during follow-up., Methods: CMRI and echo were performed in 96 precapillary PH patients. In 38 patients a second set of a CMRI and echo were available. Retrospectively, echo-derived right ventricular fractional area change (RVFAC), tricuspid annulus plane systolic excursion (TAPSE), fractional transversal (FTWM), and longitudinal wall motion (FLWM) were assessed and compared with CMRI-derived-RVEF. Furthermore, the changes in RVFAC, TAPSE, FTWM, and FLWM during follow-up were compared with the change in CMRI-derived-RVEF., Results: All four echo parameters were significantly correlated to CMRI-derived-RVEF. The strongest relationship was seen between CMRI-derived-RVEF and RVFAC (r 2 =0.567). However, sensitivity for predicting a deterioration in CMRI-derived RVEF was poor for all four echo-derived parameters (ranging from 33% to 56%)., Conclusions: Although RVFAC, TAPSE, FTWM, and FLWM were significantly correlated to CMRI-derived-RVEF, all four echo parameters showed a low sensitivity for predicting a deterioration in CMRI-derived RVEF during follow-up. Therefore, RVFAC, TAPSE, FTWM, and FLWM are not suitable parameters for the serial assessment of RV systolic function in patients with precapillary PH., (Copyright © 2016 Japanese College of Cardiology. Published by Elsevier Ltd. All rights reserved.)

Cardiac magnetic resonance imaging of the pressure overloaded right ventricle (RV) of precapillary pulmonary hypertension (PH) patients, exhibits late gadolinium enhancement at the interventricular insertion regions, a phenomenon which has been linked to focal fibrosis. Native T1-mapping is an alternative technique to characterize myocardium and has the advantage of not requiring the use of contrast agents. The aim of this study was to characterize the myocardium of idiopathic pulmonary arterial hypertension (IPAH), systemic scleroderma related PH (PAH-Ssc) and chronic thromboembolic PH (CTEPH) patients using native T1-mapping and to see whether native T1-values were related to disease severity. Furthermore, we compared native T1-values between the different precapillary PH categories. Native T1-mapping was performed in 46 IPAH, 14 PAH-SSc and 10 CTEPH patients and 10 control subjects. Native T1-values were assessed using regions of interest at the RV and LV free wall, interventricular septum and interventricular insertion regions. In PH patients, native T1-values of the interventricular insertion regions were significantly higher than the native T1-values of the RV free wall, LV free wall and interventricular septum. Native T1-values at the insertion regions were significantly related to disease severity. Native T1-values were not different between IPAH, PAH-Ssc and CTEPH patients. Native T1-values of the interventricular insertion regions are significantly increased in precapillary PH and are related to disease severity. Native T1-mapping can be developed as an alternative technique for the characterization of the interventricular insertion regions and has the advantage of not requiring the use of contrast agents.

Unlabelled: Objectives When evaluating anti-tumor treatment response by dynamic contrast-enhanced magnetic resonance imaging (DCE-MRI) it is necessary to assure its validity and reproducibility. This has not been well addressed in lung tumors. Therefore we have evaluated the inter-reader reproducibility of response classification by DCE-MRI in patients with non-small cell lung cancer (NSCLC) treated with bevacizumab and erlotinib enrolled in a multicenter trial., Materials and Methods: Twenty-one patients were scanned before and 3 weeks after start of treatment with DCE-MRI in a multicenter trial. The scans were evaluated by two independent readers. The primary lung tumor was used for response assessment. Responses were assessed in terms of relative changes in tumor mean trans endothelial transfer rate (K(trans)) and its heterogeneity in terms of the spatial standard deviation. Reproducibility was expressed by the inter-reader variability, intra-class correlation coefficient (ICC) and dichotomous response classification., Results: The inter-reader variability and ICC for the relative K(trans) were 5.8% and 0.930, respectively. For tumor heterogeneity the inter-reader variability and ICC were 0.017 and 0.656, respectively. For the two readers the response classification for relative K(trans) was concordant in 20 of 21 patients (k=0.90, p<0.0001) and for tumor heterogeneity in 19 of 21 patients (k=0.80, p<0.0001)., Conclusions: Strong agreement was seen with regard to the inter-reader variability and reproducibility of response classification by the two readers of lung cancer DCE-MRI scans., (Copyright © 2015 Elsevier Ireland Ltd. All rights reserved.)

Background: Even after years of stable response to therapy, patients with idiopathic pulmonary arterial hypertension (IPAH) may show an unexpected clinical deterioration due to progressive right ventricular (RV) failure. Therefore, the aim of this study was to assess in 5-year clinically stable patients with IPAH whether initial differences or subsequent changes in RV volumes precede late clinical progression., Methods: Included were 22 clinically stable patients with IPAH as reflected by stable or improving New York Heart Association functional class II-III and exercise capacity during 5 years of follow-up. Twelve patients subsequently remained stable during a total follow-up of 10 years, whereas 10 other patients showed late progression leading to death or lung transplantation after a follow-up of 8 years. All patients underwent right-sided heart catheterization and cardiac MRI at baseline and at 1½, 3½, 6½, and, if still alive, 10 years follow-up., Results: Baseline hemodynamics were comparable in both groups and remained unchanged during the entire follow-up period. Baseline RV end-systolic volume (RVESV) was higher and RV ejection fraction (RVEF) was lower in late-progressive patients. Late-progressive patients demonstrated a gradually increased RV end-diastolic volume and RVESV and a decline in RVEF, whereas long-term stable patients did not show any RV changes., Conclusions: In patients with stable IPAH for 5 years, subsequent late disease progression is preceded by changes in RV volumes. The results indicate that monitoring RV volumes anticipates clinical worsening, even at a time of apparent clinical stability.

In pulmonary hypertension, exercise is limited by an impaired right ventricular (RV) stroke volume response. We hypothesized that improvement in exercise capacity after pulmonary endarterectomy (PEA) for chronic thromboembolic pulmonary hypertension (CTEPH) is paralleled by an improved RV stroke volume response. We studied the extent of PEA-induced restoration of RV stroke volume index (SVI) response to exercise using cardiac magnetic resonance imaging (cMRI). Patients with CTEPH (n = 18) and 7 healthy volunteers were included. Cardiopulmonary exercise testing and cMRI were performed before and 1 year after PEA. For cMRI studies, pre- and post-operatively, all patients exercised at 40% of their preoperative cardiopulmonary exercise testing-assessed maximal workload. Post-PEA patients (n = 13) also exercised at 40% of their postoperative maximal workload. Control subjects exercised at 40% of their predicted maximal workload. Preoperatively, SVI (n = 18) decreased during exercise from 35.9 ± 7.4 to 33.0 ± 9.0 ml·m(2) (p = 0.023); in the control subjects, SVI increased (46.6 ± 7.6 vs 57.9 ± 11.8 ml·m(-2), p = 0.001). After PEA, the SVI response (ΔSVI) improved from -2.8 ± 4.6 to 4.0 ± 4.6 ml·m(2) (p <0.001; n = 17). On exercise at 40% of the postoperative maximal workload, SVI did not increase further and was still significantly lower compared with controls. Moreover, 4 patients retained a negative SVI response, despite (near) normalization of their pulmonary hemodynamics. The improvement in SVI response was accompanied by an increased exercise tolerance and restoration of RV remodeling. In conclusion, in CTEPH, exercise is limited by an impaired stroke volume response. PEA induces a restoration of SVI response to exercise that appears, however, incomplete and not evident in all patients., (Copyright © 2014 Elsevier Inc. All rights reserved.)

Pulmonary arterial hypertension (PAH) is a progressive disease characterized by remodeling and vasoconstriction of the pulmonary vasculature, ultimately leading to right ventricular (RV) failure and death. Recent developments in echocardiography, cardiovascular magnetic resonance imaging, computed tomography, and positron emission tomography allow advanced, noninvasive, in vivo assessment of the RV and have contributed to the identification of risk factors, prognostic factors, and monitoring of therapeutic responses in patients with PAH. Although far from reaching its future potential, these techniques have not only provided global RV assessment but also allowed evaluation of changes in cellular and molecular tissue processes, such as metabolism, oxygen balance and ischemia, angiogenesis, and apoptosis. Integrated application of these techniques could provide full insights into the different pathophysiological aspects of a failing RV in the setting of PAH. Recent advances in hybrid imaging have implemented simultaneous measurements of myocardial and vascular interactions and will be one of the most important potential future developments.

To assess the contribution of right ventricular (RV) trabeculae and papillary muscles (TPM) to RV mass and volumes in controls and patients with pulmonary arterial hypertension (PAH). Furthermore, to evaluate whether TPM shows a similar response as the RV free wall (RVFW) to changes in pulmonary artery pressure (PAP) during follow-up. 50 patients underwent cardiac magnetic resonance (CMR) and right heart catheterization at baseline and after one-year follow-up. Furthermore 20 controls underwent CMR. RV masses were assessed with and without TPM. TPM constituted a larger proportion of total RV mass and RV end-diastolic volume (RVEDV) in PAH than in controls (Mass: 35 ± 7 vs. 25 ± 5 %; p < 0.001; RVEDV: 17 ± 6 vs. 12 ± 6 %; p = 0.003). TPM mass was related to the RVFW mass in patients (baseline: R = 0.65; p < 0.001; follow-up: R = 0.80; p < 0.001) and controls (R = 0.76; p < 0.001). In PAH and controls, exclusion of TPM from the assessment resulted in altered RV mass, volumes and function than when included (all p < 0.01). Changes in RV TPM mass (β = 0.44; p = 0.004) but not the changes in RVFW mass (p = 0.095) were independently related to changes in PAP during follow-up. RV TPM showed a larger contribution to total RV mass in PAH (~35 %) compared to controls (~25 %). Inclusion of TPM in the analyses significantly influenced the magnitude of the RV volumes and mass. Furthermore, TPM mass was stronger related to changes in PAP than RVFW mass. Our results implicate that TPM are important contributors to RV adaptation during pressure overload and cannot be neglected from the RV assessment.

Background: Until now, many investigators have focused on describing right ventricular (RV) dysfunction in groups of patients with pulmonary arterial hypertension (PAH), but very few have addressed the deterioration of RV function over time. The aim of this study was to investigate time courses of RV geometric changes during the progression of RV failure., Methods: Forty-two patients with PAH were selected who underwent right-sided heart catheterization and cardiac MRI at baseline and after 1-year follow-up. Based on the survival after this 1-year run-in period, patients were classified into two groups: survivors (26 patients; subsequent survival of > 4 years) and nonsurvivors (16 patients; subsequent survival of < 4 years). Four-chamber cine imaging was used to quantify RV longitudinal shortening (apex-base distance change), RV transverse shortening (septum-free wall distance change), and RV fractional area change (RVFAC) between end diastole and end systole., Results: Longitudinal shortening, transverse shortening, and RVFAC measured at the beginning of the run-in period and 1 year later were significantly higher in subsequent survivors than in nonsurvivors (P < .05). Longitudinal shortening did not change during the run-in period in either patient group. Transverse shortening and RVFAC did not change during the run-in period in subsequent survivors but did decrease in subsequent nonsurvivors (P < .05). This decrease was caused by increased leftward septal bowing., Conclusions: Progressive RV failure in PAH is associated with a parallel decline in longitudinal and transverse shortening until a floor effect is reached for longitudinal shortening. A further reduction of RV function is due to progressive leftward septal displacement. Because transverse shortening incorporates both free wall and septum movements, this parameter can be used to monitor the decline in RV function in end-stage PAH.

Background: Interventricular mechanical dyssynchrony is a characteristic of pulmonary hypertension. We studied the role of right ventricular (RV) wall stress in the recovery of interventricular dyssynchrony, after pulmonary endarterectomy (PEA) in chronic thromboembolic pulmonary hypertension (CTEPH)., Methods: In 13 consecutive patients with CTEPH, before and 6 months after pulmonary endarterectomy, cardiovascular magnetic resonance myocardial tagging was applied. For the left ventricular (LV) and RV free walls, the time to peak (Tpeak) of circumferential shortening (strain) was calculated. Pulmonary Artery Pressure (PAP) was measured by right heart catheterization within 48 hours of PEA. Then the RV free wall systolic wall stress was calculated by the Laplace law., Results: After PEA, the left to right free wall delay (L-R delay) in Tpeak strain decreased from 97 ± 49 ms to -4 ± 51 ms (P < 0.001), which was not different from normal reference values of -35 ± 10 ms (P = 0.18). The RV wall stress decreased significantly from 15.2 ± 6.4 kPa to 5.7 ± 3.4 kPa (P < 0.001), which was not different from normal reference values of 5.3 ± 1.39 kPa (P = 0.78). The reduction of L-R delay in Tpeak was more strongly associated with the reduction in RV wall stress (r = 0.69,P = 0.007) than with the reduction in systolic PAP (r = 0.53, P = 0.07). The reduction of L-R delay in Tpeak was not associated with estimates of the reduction in RV radius (r = 0.37,P = 0.21) or increase in RV systolic wall thickness (r = 0.19,P = 0.53)., Conclusion: After PEA for CTEPH, the RV and LV peak strains are resynchronized. The reduction in systolic RV wall stress plays a key role in this resynchronization.

Background: Pulmonary artery (PA) dilatation is one of the consequences of pulmonary arterial hypertension (PAH) and is used for noninvasive detection. However, it is unclear how the size of the PA behaves over time and whether it is related to pressure changes. The aim of this study was to evaluate PA size during follow-up in treated patients with PAH and whether it reflects pulmonary vascular hemodynamics., Methods: Fifty-one patients with PAH who underwent at least two right-sided heart catheterizations (RHCs) together with cardiac MRI (CMR) were included in this study. Another 18 patients who had normal pressure at RHC were included for comparison at baseline. From RHC, we derived PA pressures and cardiac output. From the CMR images we derived PA diameter (PAD) and the ratio of the PAD and ascending aorta diameter., Results: The PAD was significantly larger in patients with PAH than in patients without PAH (P < .001). A ratio of the PAD and ascending aorta diameter > 1 had a positive predictive value of 92% for PAH. Mean follow-up time was 942 days, and there was a significant dilatation during this period (P < .001). The change of the PAD did not correlate with the changes in pressure or cardiac output. A moderate correlation with follow-up time was found (r = 0.56; P < .001)., Conclusions: A dilatated PA is useful for identifying patients with PAH. However, during patient follow-up, progressive dilatation of the PA is independent of the change in PA pressure and cardiac output and might become independent from hemodynamics.

Rationale: Pulmonary hypertension (PH) is characterized by increased arterial load requiring more right ventricular (RV) hydraulic power to sustain adequate forward blood flow. Power can be separated into a mean and oscillatory part. The former is associated with mean and the latter with pulsatile blood flow and pressure. Because mean power provides for net blood flow, the ratio of oscillatory to total power (oscillatory power fraction) preferably should be small. It is unknown whether this is the case in pulmonary arterial hypertension (PAH)., Objectives: To derive components of power generated by the right ventricle in PAH., Measurements and Main Results: Thirty-five patients with idiopathic PAH (IPAH) and 14 subjects without PH were included. The patients were divided in two groups, "moderate" and "high," based on pulmonary artery (PA) pressure. PA pressures were obtained by right heart catheterization and PA flows by magnetic resonance imaging. Total hydraulic power (Power(total)) was calculated as the integral product of pressure and flow. Mean hydraulic power (Power(mean)) was calculated as mean pulmonary artery pressure times mean flow. Their difference is oscillatory power (Power(oscill)). Total hydraulic power in subjects without PH compared with moderate and high IPAH was 0.29 ± 0.10 W (n = 14), 0.52 ± 0.14 W (n = 17), and 0.73 ± 0.24 W (n = 18), respectively. The oscillatory power fraction is approximately 23% and not different between groups., Conclusions: In this study, oscillatory power fraction is constant at 23% in non-PH and IPAH, implying that a considerable amount of power is not used for forward flow, making the RV less efficient with respect to its arterial load. Our findings emphasize the need to develop new therapy strategies to optimize RV power output in PAH.

Background: Normal left ventricular (LV) torsion is caused by opposite basal and apical rotation. Opposite rotation can be lost in heart failure, but might be restored by pacing; therefore, the predictive value of the loss of opposite base-apex rotation in heart failure patients for the response to cardiac resynchronization therapy (CRT) was studied., Methods and Results: In 34 CRT candidates and 12 controls, basal and apical LV rotations were calculated using magnetic resonance image tagging. Loss of opposite rotation was quantified by the correlation between both rotation curves: a negative correlation indicates normal, opposite rotation and a positive correlation indicates that base and apex rotate in the same direction. In patients, LV pressure was measured invasively during biventricular stimulation. Acute response to CRT was defined by >10% increase in dP/dt(max) relative to baseline. LV volume was determined at baseline and 8 months follow-up using echocardiography. The base-apex rotation correlation (BARC) was significantly higher in acute responders (n=22) than in nonresponders (n=12) and controls (0.64+/-0.51, -0.23+/-0.67, and -0.68+/-0.22, respectively; P=.001). The sensitivity and specificity for prediction of acute response were 82% and 83%, respectively, at a cutoff value of 0.5. At follow-up, volumes could be analyzed in 18 patients. In the group with BARC >0.5, end-diastolic volume decreased by 7% (NS), end-systolic volume by 16%, and ejection fraction increased by 28% (both P=.02), whereas in the group with BARC <0.5, no significant changes were observed., Conclusions: The loss of opposite base-apex rotation in patients eligible for CRT is an excellent predictor of acute response and is associated with LV reverse remodeling.

Objectives: To compare regional left ventricular (LV) volume curves obtained with real time three-dimensional echocardiography (RT3DE) with two-dimensional circumferential strain curves obtained by MRI in cardiac resynchronization therapy candidates., Background: Several methods using either ultrasound or MRI are used to quantify mechanical dyssynchrony (MD). Theoretically, LV volume and circumferential strain seem related, since both measures are connected to the radius of the ventricle., Methods: In 21 patients with chronic heart failure, RT3DE and tagged MRI were performed subsequently. Regional LV volume was computed from the ultrasound images. From the MR images, regional circumferential strain was calculated. Cross-correlations with time lags of 1% of the cardiac cycle were performed to compare the curves in corresponding LV segments. Furthermore, peak septal to lateral (SL) delays were compared between modalities., Results: High correlations were found between the curves (r(2) = 0.65 +/- 0.19), but regional differences in time delay between modalities were observed. In the septum, the volume curve was earlier than the strain curve by 1.8 +/- 17.0 time-lags (n.s.), while in the lateral wall, the volume curve was earlier by 3.3 +/- 12.0 time-lags (P < 0.02). There was a non-significant difference between SL delays in the two modalities (volume: -1.0 +/- 8.6%, strain: 3.0 +/- 12.7%, P = 0.17, a positive sign indicates that the lateral wall is delayed)., Conclusions: High correlations were observed between both modalities, but regional differences in time-delay were found. This is possibly inherent to the method of echocardiographic volume calculation and hampers the comparison of both measures for the quantification of MD.

Background: Right ventricular (RV) dysfunction is associated with increased morbidity and mortality in patients with chronic thromboembolic pulmonary hypertension (CTEPH) who undergo pulmonary endarterectomy (PEA). We studied whether plasma brain natriuretic peptide (BNP) levels can be used to identify RV dysfunction in CTEPH patients. Therefore, plasma BNP levels were studied in relation to cardiac remodeling and function as determined by cardiac magnetic resonance imaging (MRI)., Methods: Thirty-eight patients with CTEPH (55 +/- 15 years), and ten healthy controls (46 +/- 15 years) were studied. The BNP was determined by an immunoradiometric assay., Results: The CTEPH patients had a mean pulmonary artery pressure of 49 +/- 13 mm Hg, cardiac index 2.1 +/- 0.7 l x min(-1) x m(-2), and pulmonary vascular resistance of 867 +/- 432 dynes x s x cm(-5). In CTEPH patients, compared with controls, right ventricular (RV) remodeling was demonstrated. In the patients, BNP was increased and correlated (all p < 0.0001; Spearman rank test) with MRI parameters of RV remodeling and function: end diastolic (r = 0.71) and end systolic (r = 0.74) volumes, RV mass (r = 0.68), leftward ventricular septal bowing (r = -0.80) and ejection fraction (EF; r = -0.81). By receiver operating curve analysis, BNP levels of 11.5 picomole (pmol)/L and 48.5 pmol/L, respectively, detected RV dysfunction as defined by RVEF less than 0.45 and less than 0.30, respectively, with high sensitivity and specificity. Hemodynamically, BNP levels greater than 48.5 pmol/L identified the most severely affected patients., Conclusions: In CTEPH patients, BNP levels correlate with RV remodeling and can be used to identify RV dysfunction. Future studies are warranted on the role of BNP to identify "high risk" CTEPH patients and its relation to postoperative hemodynamic outcome, RV failure, and mortality.

Background: The effect of a left bundle branch block (LBBB) on cardiac function and remodeling in patients at different stages of heart failure (HF) is unknown. We used cardiac magnetic resonance imaging (CMR) to evaluate the effect of LBBB on left ventricular (LV) remodeling, mechanical dyssynchrony, functional mitral regurgitation (FMR) and deformation of the mitral valve apparatus (MVA) in LBBB patients at different stages of HF., Methods: In 12 LBBB patients with HF, 4 patients with isolated LBBB, and 4 controls, cine CMR was performed to measure LV remodeling, FMR grade and deformation of the MVA. CMR tagging was used to measure septal-to-lateral onset of shortening delay and coefficient of circumferential strain variation (CV) to quantify dyssynchrony., Results: LV end-diastolic volume (LVEDV) and end-systolic volume (LVESV) were largest in LBBB patients with HF. Patients with isolated LBBB tended to have a larger LVESV and smaller LV ejection fraction compared to controls, (56 +/- 22 ml/m2 versus 45 +/- 9 ml/m2, P = ns, 42 +/- 9% versus 53 +/- 4 %, P = ns). QRS duration and septal-to-lateral-onset-of-shortening delay were comparable between LBBB patients with HF and isolated LBBB patients, CV was larger (98 +/- 45 versus 40 +/- 4, P < 0.05). MVA tenting and FMR were present both in LBBB patients with HF and patients with isolated LBBB and were not observed in controls., Conclusion: The presence of a LBBB in asymptomatic patients is related to mechanical dyssynchrony and deformation of the MVA and may be associated with LV remodeling. If confirmed, close monitoring or even timely initiation of therapy may be warranted in patients with isolated LBBB. This advocates to conduct a longitudinal CMR follow-up study on the clinical course in patients with isolated LBBB.

Aims: This study investigated whether right ventricular (RV) diastolic function is impaired in pulmonary hypertension (PH) patients, and whether it is related to RV mass and afterload. In addition, the effects of an acute reduction of RV afterload by the oral intake of sildenafil were studied. Finally, we assessed whether diastolic function is related to cardiac parameters of disease severity., Methods and Results: Twenty-five PH patients and 11 control subjects were studied. Right-heart catheterization and N-terminal pro-brain natriuretic peptide (NT-proBNP) sampling were performed in patients. MRI measured RV ejection fraction, mass, and diastolic function. Isovolumic relaxation time (IVRT), normalized early peak filling rate (E), atrium-induced peak filling rate (A), and E/A ratio described diastolic function. Compared to control subjects, patients had prolonged mean (+/- SD) IVRT (133.5 +/- 53.2 vs 29.3 +/- 20.8 ms, respectively; p < 0.001), decreased E (3.0 +/- 1.6 vs 6.4 +/- 2.5 s(-1), respectively; p < 0.001) and E/A ratio (1.1 +/- 0.7 vs 5.3 +/- 4.9, respectively; p < 0.001), and increased A (3.0 +/- 1.4 vs 1.5 +/- 0.9 s(-1), respectively; p = 0.001). IVRT was related to RV mass (r(25) = 0.56; p = 0.005) and pulmonary vascular resistance (r(25) = 0.74; p < 0.0001). Sildenafil therapy reduced RV afterload and improved RV diastolic and systolic function. IVRT was correlated with NT-proBNP level (r = 0.70; p < 0.001), and was inversely related to cardiac index (r = -0.70; p < 0.001) and RV ejection fraction (r = -0.69; p < 0.001)., Conclusion: In PH patients, RV diastolic dysfunction is related to RV mass and afterload. RV diastolic function improves by reducing afterload. The correlations between diastolic function and prognostic parameters showed that diastolic function is most impaired in patients with severe disease.

Background: Pneumonectomy not only reduces the pulmonary vascular bed but also changes the position of the heart and large vessels, which may affect the function of the heart. We investigated long-term effects of pneumonectomy on right ventricular (RV) and left ventricular (LV) function and whether this function is influenced by the side of pneumonectomy or the migration of the heart to its new position., Methods: In 15 patients who underwent pneumonectomy and survived for more than 5 years, we evaluated by dynamic magnetic resonance imaging the function of the RV and LV and the position of the heart within the thorax., Results: Long-term effect of pneumonectomy on the position of the heart is characterized by a lateral shift after right-sided pneumonectomy and rotation of the heart after left-sided pneumonectomy. Postoperatively, heart rate was high (p = 0.006) and stroke volume was low (p = 0.001), compared with the reference values, indicating impaired cardiac function. Patients after right-sided pneumonectomy had an abnormal low RV end-diastolic volume of 99 +/- 29 mL together with a normal LV function. No signs of RV hypertrophy were found. In left-sided pneumonectomy patients, RV volumes were normal whereas LV ejection fraction was abnormally low., Conclusions: The long-term effects of pneumonectomy on the position of the heart are characterized by a lateral shift in patients after right-sided pneumonectomy and rotation of the heart in patients after left-sided pneumonectomy. Overall, cardiac function in long-term survivors after pneumonectomy is compromised, and might be explained by the altered position of the heart.

Objectives: Pulmonary arterial hypertension causes right ventricular remodeling; that is, right ventricular dilatation, hypertrophy, and leftward ventricular septal bowing. We studied the effect of pulmonary endarterectomy on the restoration of right ventricular remodeling in patients with chronic thromboembolic pulmonary hypertension by magnetic resonance imaging., Methods: In 17 patients with chronic thromboembolic pulmonary hypertension, before and at least 4 months after pulmonary endarterectomy, and in 12 healthy controls, right ventricular and left ventricular end-diastolic and end-systolic volumes (milliliters) and mass (grams per meter squared) and leftward ventricular septal bowing (1 divided by the radius of curvature in centimeters) were determined by magnetic resonance imaging., Results: Before pulmonary endarterectomy, right ventricular volumes, left ventricular end-diastolic volume, right ventricular mass, and leftward ventricular septal bowing differed significantly between patients with chronic thromboembolic pulmonary hypertension and healthy control subjects. After pulmonary endarterectomy, pulmonary hemodynamics improved, and right and left ventricular volumes and leftward ventricular septal bowing normalized; right ventricular mass decreased significantly (46 +/- 14 to 31 +/- 9 g x m(-2), P< .0005), but did not completely normalize. The change in total pulmonary resistance correlated with the change in right ventricular ejection fraction (r = 0.50, P < .05), right ventricular mass (r = 0.63, P < .01), and leftward ventricular septal bowing (r = 0.50, P < .05)., Conclusions: Right ventricular remodeling was observed in patients with chronic thromboembolic pulmonary hypertension and restored almost completely after a hemodynamically successful pulmonary endarterectomy. Magnetic resonance imaging is a valuable tool to evaluate cardiac remodeling and function in patients with chronic thromboembolic pulmonary hypertension, both before and after pulmonary endarterectomy.

The intra-breath technique to measure acetylene absorption offers the possibility to determine augmentation of the pulmonary blood flow per heart beat (Q(C)) as an estimate of the stroke volume response during exercise. However, this method has not been compared with a validated test until now. Therefore, the aim of this study was to compare Q(C) with stroke volume (SV(MRI)) determined by magnetic resonance imaging (MRI) at rest and during exercise in healthy subjects and patients. For this purpose, ten healthy subjects and ten patients with idiopathic pulmonary arterial hypertension (iPAH) with expected impaired stoke volume response during exercise were measured by both methods. Exercise-induced changes in Q(C) and SV(MRI) were correlated in healthy controls (r = 0.75, p < 0.05). Compared to healthy controls, Q(C) increased less during exercise in iPAH patients (11 +/- 17 ml versus 33 +/- 12 ml, p < 0.05). A similar difference in stroke volume response to exercise between the two groups was measured by MRI (-0.6 +/- 8 ml versus 23 +/- 12 ml, p < 0.05, respectively). Hence, intra-breath and MRI measurements showed similar differences in exercise-induced changes in stroke volume between controls and patients. From these results it can be concluded that the intra-breath measurement of acetylene absorption might be of value as a non-invasive tool to estimate stroke volume augmentation during exercise and can detect differences in stroke volume responses between iPAH patients and healthy subjects.

Background: Regional differences in resting myocardial blood flow (MBF) have been observed in patients with hypertrophic cardiomyopathy (HCM), but their determinants are currently unknown. This study verifies whether MBF at rest in HCM is related to delayed contrast enhancement (DCE) or regional systolic function (or both) as determined by magnetic resonance imaging., Methods and Results: Fourteen patients with HCM were studied. MBF was measured with positron emission tomography by use of oxygen 15-labeled water. DCE and tissue tagging, to calculate end-systolic circumferential shortening (Ecc), were obtained with magnetic resonance imaging. The mean resting MBF was 0.78 +/- 0.19 mL x min(-1) x mL(-1), and there was a trend toward reduced MBF in the septum (0.72 +/- 0.11 mL x min(-1) x mL(-1)) compared with that in the lateral wall (0.84 +/- 0.29 mL x min(-1) x mL(-1)) (P = .092). The distribution patterns of DCE and Ecc were both heterogeneous, displaying significantly increased enhancement and impaired regional systolic function in the hypertrophic septum compared with the lateral wall (both P < .001). Resting MBF was inversely related to the extent of DCE (r = -0.30, P < .001), whereas MBF was not significantly related to Ecc (r = -0.15, P = .072)., Conclusions: Regional heterogeneity of resting perfusion in HCM is related to the extent of DCE but not to regional systolic function.

The aim of this study was to investigate the contribution of direct right-to-left ventricular interaction to left ventricular filling and stroke volume in 46 patients with pulmonary arterial hypertension (PAH) and 18 control subjects. Stroke volume, right and left ventricular volumes, left ventricular filling rate, and interventricular septum curvature were measured by magnetic resonance imaging and left atrial filling by transesophageal echocardiography. Stroke volume, left ventricular end-diastolic volume, and left ventricular peak filling rate were decreased in PAH patients compared with control subjects: 28 +/- 13 vs. 41 +/- 10 ml/m(2) (P < 0.001), 46 +/- 14 vs. 61 +/- 14 ml/m(2) (P < 0.001), and 216 +/- 90 vs. 541 +/- 248 ml/s (P < 0.001), respectively. Among PAH patients, stroke volume did not correlate to right ventricular end-diastolic volume or mean pulmonary arterial pressure but did correlate to left ventricular end-diastolic volume (r = 0.62, P < 0.001). Leftward interventricular septum curvature was correlated to left ventricular filling rate (r = 0.64, P < 0.001) and left ventricular end-diastolic volume (r = 0.65, P < 0.001). In contrast, left atrial filling was normal and not correlated to left ventricular end-diastolic volume. In PAH patients, ventricular interaction mediated by the interventricular septum impairs left ventricular filling, contributing to decreased stroke volume.