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Saouti N, Westerhof N, Heiderman F, Marcus JT, Stergiopulos N, Westerhof BE, Boonstra A, Postmus PE, Vonk-Noordegraaf A. RC time constant of single lung equals that of both lungs together: a study in chronic thromboembolic pulmonary hypertension. Am J Physiol Heart Circ Physiol 297:H2154-H2160, 2009. First published October 2, 2009; doi: 10.1152/ajpheart.00694.2009.--The product of resistance, R, and compliance, C(RC time), of the entire pulmonary circulation is constant. It is unknown if this constancy holds for individual lungs. We determined R and C in individual lungs in chronic thromboembolic pulmonary hypertension(CTEPH) patients where resistances differ between both lungs. Also, the contribution of the proximal pulmonary arteries(PA) to total lung compliance was assessed. Patients(n = 23) were referred for the evaluation of CTEPH. Pressure was measured by right heart catheterization and flows in the main, left, and right PA by magnetic resonance imaging. Total, left, and right lung resistances were calculated as mean pressure divided by mean flow. Total, left, and right lung compliances were assessed by the pulse pressure method. Proximal compliances were derived from cross-sectional area change [DELTA]A and systolic-diastolic pressure difference [DELTA]P([DELTA]A/[DELTA]P) in main, left, and right PA, multiplied by vessel length. The lung with the lowest blood flow was defined 'low flow'(LF), the contralateral lung 'high flow'(HF). Total resistance was 0.57 [+ or -] 0.28 mmHg x [s.sup.-1] x [ml.sup.-1], and resistances of LF and HF lungs were 1.57 [+ or -] 0.2 vs. 1.00 [+ or -] 0.1 mmHg x [s.sup.-1] x [ml.sup.-1], respectively, P < 0.0001. Total compliance was 1.22 [+ or -] 1.1 ml/ mmHg, and compliances of LF and HF lung were 0.47 [+ or -] 0.11 and 0.62 [+ or -] 0.12 ml/mmHg, respectively, P = 0.01. Total RC time was 0.49 [+ or -] 0.2 s, and RC times for the LF and HF lung were 0.45 [+ or -] 0.2 and 0.45 [+ or -] 0.1 s, respectively, not different. Proximal arterial compliance, given by the sum of main, right, and left PA compliances, was only 19% of total lung compliance. The RC time of a single lung equals that of both lungs together, and pulmonary arterial compliance comes largely from the distal vasculature. compliance; pulmonary hypertension; resistance and capacitance time; resistance doi: 10.1152/ajpheart.00694.2009

Abstract 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.

The disadvantages of mitral valve replacement with a bioprosthesis in the long-term may not play an important role if the shorter life expectancy of older patients is taken into account. This study aims to evaluate whether mitral valve replacement in the elderly is associated with similar outcome compared to repair in the short- and long-term. All patients aged 70 years and older undergoing minimally invasive mitral valve surgery were studied retrospectively. Primary outcome was 30-day complication rate, secondary outcome was long-term survival and freedom from re-operation. 223 Patients underwent surgery (124 replacement and 99 repair) with a mean age of 76.4 ± 4.2 years. 30-Day complication rate (replacement 73.4% versus repair 67.7%; p=.433), 30-day mortality (replacement 4.0% versus repair 1.0%; p=.332) and 30-day stroke rate (replacement 0.0% versus repair 1.0%; p=.910) were similar in both groups. Multivariable cox regression revealed higher age, diabetes and left ventricular dysfunction as predictors for reduced long-term survival, while a valve replacement was no predictor for reduced survival. Sub analysis of patients with degenerative disease showed no difference in long-term survival after propensity weighting (HR 1.4; 95%CI 0.84 - 2.50; p=.282). The current study reveals that mitral valve repair and replacement in the elderly can be achieved with good short- and long-term results. Long-term survival was dependent on patient related risk factors and not on the type of operation (replacement versus repair)., (Copyright © 2021 Elsevier Inc. All rights reserved.)

Minimally invasive mitral valve surgery (MIMVS) has become the standard approach for mitral valve pathology in many centres. The anterolateral mini thoracotomy access is beneficial in reoperative surgery by avoiding repeat sternotomy associated risks. The aim of this study is to analyse the safety of this technique. All patients undergoing reoperative MIMVS between 2008 and 2019 were studied retrospectively. Primary endpoint was 30-day major complications and mortality; secondary outcome was long term survival, reoperation rate and rate of more than moderate recurrent regurgitation. 146 Patients underwent reoperative MIMVS with a mean age of 68 ± 8 years. The composite outcome of 30-day major complication and mortality was 29.5%. 30-Day mortality was 6.2% and stroke rate 3.4%. Survival for the whole cohort was 89.7 ± 2.5% at 1-year, 71.6 ± 4.3% at 5 year and 50.9 ± 5.9% at 8-year follow up. Cox regression analysis revealed reduced left ventricular function (HR 2.8; 95%CI 1.5 - 5.0), GFR < 60 (HR 2.1; 95%CI 1.2 - 3.7) and active endocarditis (HR 6.4; 95%CI 2.7 - 15.4) as variables associated with reduced long-term survival. The cumulative incidence of re-operation after mitral valve replacement was 11.3 ± 3.2% at 5-year and for repair 16.2 ± 7.5% at 5-year. The cumulative incidence of more than moderate recurrent regurgitation after mitral valve repair was 25.4 ± 9.0% at 3-year. Minimally invasive access in reoperative mitral valve surgery in the current study showed similar 30-day mortality and stroke rate compared to repeat sternotomy results reported in literature., (Copyright © 2021 Elsevier Inc. All rights reserved.)

Objective: Minimally invasive surgery is increasingly adopted as an alternative to conventional sternotomy for mitral valve pathology in many centres worldwide. A systematic safety analysis based on a comprehensive list of pre-specified 30-day complications defined by the Mitral Valve Academic Consortium (MVARC) criteria is lacking. The aim of the current study was to systematically analyse the safety of minimally invasive mitral valve surgery in our centre based on the MVARC definitions., Methods: All consecutive patients undergoing minimally invasive mitral valve surgery through right mini-thoracotomy in our institution within 10 years were studied retrospectively. The primary outcome was a composite of 30-day major complications based on MVARC definitions., Results: 745 patients underwent minimally invasive mitral valve surgery (507 repair, 238 replacement), with a mean age of 62.9±12.3 years. The repair was successful in 95.8%. Overall 30-day mortality was 1.2% and stroke rate 0.3%. Freedom from any 30-day major complications was 87.2%, and independent predictors were left ventricular ejection fraction <50% (OR 1.78; 95% CI 1.02 to 3.02) and estimated glomerular filtration rate <60 mL/min/1.73 m 2 (OR 1.98; 95% CI 1.17 to 3.26)., Conclusions: Minimally invasive mitral valve surgery is a safe technique and is associated with low 30-day mortality and stroke rate., Competing Interests: Competing interests: None declared., (© Author(s) (or their employer(s)) 2020. Re-use permitted under CC BY-NC. No commercial re-use. See rights and permissions. Published by BMJ.)

Objectives: To evaluate the indications, perioperative strategy and postoperative outcome of surgical left subclavian artery (LSA) revascularization combined with thoracic endovascular aortic repair (TEVAR) covering the LSA., Methods: Between 2000 and 2017, a total of 101 consecutive patients underwent surgical revascularization of the LSA prior to, concomitant or following TEVAR. Revascularization was performed through a small supraclavicular incision and consisted of a transposition or bypass graft, using intraoperative transcranial Doppler monitoring. Data regarding indication, procedural details and postoperative results were retrospectively analysed., Results: In total, 63 subclavian-carotid bypass grafts and 38 subclavian-carotid transpositions were performed in the context of TEVAR. The majority was performed prior to stent grafting to reduce the risk of stroke (n = 50), spinal cord ischaemia (n = 20), left arm malperfusion (n = 10) or to preserve a patent left internal mammary artery coronary bypass graft (n = 2). Secondary revascularization was performed in 14 patients, 2 times immediately due to acute left arm malperfusion and 12 times to treat invalidating left arm claudication. No in-hospital mortality and permanent spinal cord ischaemia occurred. Two (2%) ischaemic strokes were observed in patients with concomitant procedures, and none when separate, staged procedures were performed. Additional complications observed were permanent peripheral nerve palsies (9%), chyle leakage requiring diet (6%) and 1 bypass occlusion requiring a redo procedure., Conclusions: In patients predominantly selected upon the anticipated risk of (posterior) stroke, spinal cord ischaemia and left arm malperfusion, surgical revascularization of the LSA proved to be a safe treatment option to preserve antegrade LSA flow in the context of TEVAR.

The function of the right ventricle (RV) determines the prognosis of patients with pulmonary hypertension. While much progress has been made in the treatment of pulmonary hypertension, therapies for the RV are less well established. In this review of treatment strategies for the RV, first we focus on ways to reduce wall stress since this is the main determinant of changes to the ventricle. Secondly, we discuss treatment strategies targeting the detrimental consequences of increased RV wall stress. To reduce wall stress, afterload reduction is the essential. Additionally, preload to the ventricle can be reduced by diuretics, by atrial septostomy, and potentially by mechanical ventricular support. Secondary to ventricular wall stress, left-to-right asynchrony, altered myocardial energy metabolism, and neurohumoral activation will occur. These may be targeted by optimising RV contraction with pacing, by iron supplement, by angiogenesis and improving mitochondrial function, and by neurohumoral modulation, respectively. We conclude that several treatment strategies for the right heart are available; however, evidence is still limited and further research is needed before clinical application can be recommended., (© The Author 2017. Published on behalf of the European Society of Cardiology.)

Background: To describe the transapical approach for thoracic endovascular aortic repair (TEVAR)., Methods: Three patients, 2 elective and 1 emergent, with thoracic aorta aneurysm are described with vascular or direct aortic inaccessible access, who underwent TEVAR through transapical access. The technique is described in detail emphasizing the usefulness of the through-and-through guidewire, rapid pacing, and transesophageal echocardiography guidance., Results: All patients were technical successfully treated with TEVAR through transapical access. The emergent patient, however, died due to multiorgan failure., Conclusions: Our early experience shows that the transapical approach for TEVAR procedures is feasible in experienced hands. The selection of the patient and careful planning based on imaging are of paramount importance and should lead to the most suitable access site tailored to the need of the individual patient., (Copyright © 2015 Elsevier Inc. All rights reserved.)

Objectives: Intentional covering of the left subclavian artery (LSA) as part of thoracic endovascular aortic repair (TEVAR) can cause (posterior) strokes or left arm malperfusion. LSA revascularization can be done as prophylaxis against, or as treatment of, these complications. We report our experience with the surgical technique, indications and the results of LSA revascularization., Methods: Between 2000 and 2013, 51 patients of 444 patients who were treated by TEVAR, had LSA revascularization. All elective patients had a preoperative work-up with magnetic resonance angiography to evaluate the circle of Willis. In all, surgical access was through a left supraclavicular incision only., Results: The majority (90%) had prophylactic LSA revascularization because of incomplete circle of Willis and or dominant left vertebral artery (LVA) (n=29), patent left internal mammary artery (n=1), prevention spinal cord ischaemia (SCI) (n=2), prevention left arm ischaemia due to small LVA (n=2) and LVA origin in arch (n=1). Fourteen percent had secondary revascularization, either immediate because of malperfusion of the left arm (n=2) or late after TEVAR because of persisting left arm claudication (n=5). In 12 patients, the following early complications were observed: re-exploration for bleeding, n=1; left recurrent nerve paralysis, n=2; left phrenic nerve paralysis, n=1; left sympathetic chain neuropraxia, resulting in Horner's syndrome, n=3; Chyle duct lesions, resulting in persistent Chyle leakage, n=3. Neither strokes nor SCI was observed. One patient experienced occlusion of the bypass at 6 months., Conclusions: The present study shows that the procedure of LSA revascularization as part of TEVAR is safe with low morbidity consisting of mainly (transient) nerve palsy., (© The Author 2014. Published by Oxford University Press on behalf of the European Association for Cardio-Thoracic Surgery. All rights reserved.)

Arterial compliance is mainly determined by the elasticity of proximal large-conduit arteries of which the aorta is the largest contributor. Compliance forms an important part of the cardiac load and plays a role in organ (especially coronary) perfusion. To follow local changes in aortic compliance, as in aging, noninvasive determination of compliance distribution would be of great value. Our goal is to determine regional aortic compliance noninvasively in the human. In seven healthy individuals at six locations, aortic blood flow and systolic/diastolic area (ΔA) was measured with MRI. Simultaneously brachial pulse pressure (ΔP) was measured with standard cuff. With a transfer function we derived ΔP at the same aortic locations as the MRI measurements. Regional aortic compliance was calculated with two approaches, the pulse pressure method, and local area compliance (ΔA/ΔP) times segment length, called area compliance method. For comparison, pulse wave velocity (PWV) from local flows at two locations was determined, and compliance was derived from PWV. Both approaches show that compliance is largest in the proximal aorta and decreases toward the distal aorta. Similar results were found with PWV-derived compliance. Of total arterial compliance, ascending to distal arch (segments 1-3) contributes 40% (of which 15% is in head and arms), descending aorta (segments 4 and 5) 25%, and "hip, pelvic and leg arteries" 20%. Pulse pressure method includes compliance of side branches and is therefore larger than the area compliance method. Regional aortic compliance can be obtained noninvasively. Therefore, this technique allows following changes in local compliance with age and cardiovascular diseases.

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.

Introduction: Recent studies suggest that medically treated patients with inoperable chronic thromboembolic pulmonary hypertension (CTEPH) have an improved prognosis. However, only limited data are available concerning predictors of mortality in these patients. The aim of this study was to assess, and to identify, predictors of the long-term outcome of inoperable CTEPH patients., Methods: We analysed 84 inoperable CTEPH patients referred to our centre between 1999 and 2008. During follow-up (mean 32 months), 17 patients died and one underwent a lung transplantation. The 1-, 3- and 5-year survival rates were 93, 78 and 68%, respectively. Univariate analysis demonstrated that 6-min walking distance (6MWD), mean pulmonary artery pressure (mPAP), right atrial pressure (RAP) and pulmonary vascular resistance (PVR) were predictive factors for survival. In the multivariate analysis only 6MWD was independently related to poor survival (hazard ratio 0.995; 95% CI, 0.991-0.998; P=0.003). Kaplan-Meier curves showed that patients with an mPAP>40 mmHg, PVR>584 dyn s cm(-5) and RAP>12 mmHg had a very poor prognosis., Conclusions: Haemodynamic parameters (mPAP, RAP, PVR) and the 6MWD at baseline are predictive factors for mortality of medically treated inoperable CTEPH patients. A subgroup of these patients with good prognostic factors, defined by their haemodynamics and clinical measures, have an improved long-term survival and outcome.

Objective: Pulmonary endarterectomy (PEA) for chronic thromboembolic pulmonary hypertension (CTEPH) is the first treatment of choice with good short-term results. Only limited data are available concerning the long-term outcome after PEA. The purpose of this study is to evaluate the long-term survival and functional outcome after PEA with nearly 10 years experience., Method: In the period of December 1998 and December 2007 120 patients with CTEPH were referred to the St Antonius Hospital (Nieuwegein, The Netherlands) of whom 72 underwent PEA. The clinical data are collected retrospectively., Results: In-hospital mortality was (5/72) 6.9%. Since 2004 one patient died in the hospital (1/38, 2.9%). Two patients died during long-term follow-up with a median observation of 3 years. The overall 1-, 3- and 5-year survival rates were 93.1%, 91.2% and 88.7% respectively. Prior to surgery patients were in New York Heart Association functional class III (58) and IV (14) with a mean pulmonary vascular resistance of 572+/-313 dynes s cm(-5). The following data were compared before and after operation: mean pulmonary artery pressure (mPAP) decreased from 42+/-11 to 22+/-7 mmHg (p=0.0001), NT-pro BNP improved from 1527+/-1652 to 160+/-3 pg/ml (p=0.0001), 6 min walk distance (6MWD) from 359+/-124 to 518+/-11 m (p=0.0001), and almost all patients returned to functional class I or II (p=0.0001)., Conclusion: Pulmonary endarterectomy for patients with CTEPH has shown a dramatic improvement of clinical status with excellent long-term survival.