Search

Aims Coronary flow capacity (CFC) integrates quantitative hyperaemic myocardial blood flow (hMBF) and coronary flow reserve (CFR) to comprehensively assess physiological severity of coronary artery disease (CAD). This study evaluated the effects of revascularization on CFC as assessed by serial [15O]H2O positron emission tomography (PET) perfusion imaging. Methods and results A total of 314 patients with stable CAD underwent [15O]H2O PET imaging at baseline and after myocardial revascularization to assess changes in hMBF, CFR, and CFC in 415 revascularized vessels. Using thresholds for ischaemia and normal perfusion, vessels were stratified in five CFC categories: myocardial steal, severely reduced CFC, moderately reduced CFC, minimally reduced CFC, and normal flow. Additionally, the association between CFC increase and the composite endpoint of death and non-fatal myocardial infarction (MI) was studied. Vessel-specific CFC improved after revascularization (P < 0.01). Furthermore, baseline CFC was an independent predictor of CFC increase (P < 0.01). The largest changes in ΔhMBF (0.90 ± 0.74, 0.93 ± 0.65, 0.79 ± 0.74, 0.48 ± 0.61, and 0.29 ± 0.66 mL/min/g) and ΔCFR (1.01 ± 0.88, 0.99 ± 0.69, 0.87 ± 0.88, 0.66 ± 0.91, and −0.01 ± 1.06) were observed in vessels with lower baseline CFC (P < 0.01 for both). During a median follow-up of 3.5 (95% CI 3.1–3.9) years, an increase in CFC was independently associated with lower rates of death and non-fatal MI (HR 0.43, 95% CI 0.19–0.98, P = 0.04). Conclusion Successful revascularization results in an increase in CFC. Furthermore, baseline CFC was an independent predictor of change in hMBF, CFR, and subsequently CFC. In addition, an increase in CFC was associated with a favourable outcome in terms of death and non-fatal MI. [ABSTRACT FROM AUTHOR]

Aims: The relationship between coronary artery atherosclerosis and microvascular resistance remains unclear. This study aims to clarify the relationship between total atherosclerotic and vessel-specific atherosclerotic burden and microvascular resistance reserve (MRR)., Methods and Results: In this post-hoc analysis of the PACIFIC 1 trial, symptomatic patients without prior coronary artery disease (CAD) underwent [15O]H2O positron emission tomography, coronary computed tomography angiography (CCTA) and invasive fractional flow reserve (FFR). MRR was assessed across all three coronary branches, utilizing PET-derived coronary flow reserve and invasive FFR measurements. CCTA was used to assess patient and vessel-specific plaque volumes. Percentage atheroma volume (PAV) was defined as total plaque volume divided by vessel volume. The study included 142 patients (55% male, 57.5±8.6 years) with 426 vessels with a mean MRR of 3.77±1.64. While a significantly higher PAV was observed in the left anterior descending artery territory, MRR was similar across the three coronary branches. Generalized Estimating Equations without correction for cardiovascular risk factors identified that patient-specific PAV tertiles but not vessel-specific PAV tertiles were related to vessel-specific MRR. After correction for cardiovascular risk factors, compared to the first tertile of patient-specific PAV, the second tertile showed a vessel-specific MRR decrease of β=-0.362, p=0.018, and the third tertile showed a decrease of β=-0.347, p=0.024., Conclusion: In patients without prior CAD, patient-specific plaque burden was negatively associated to vessel-specific MRR; however, vessel-specific plaque burden was not related to vessel-specific MRR. Our findings suggest that the relation between atherosclerotic burden and an impaired microcirculatory function is of systemic origin., (© The Author(s) 2024. Published by Oxford University Press on behalf of the European Society of Cardiology.)

Background: Fractional flow reserve (FFR) has emerged as the invasive gold standard for assessing vessel-specific ischemia. However, FFR measurements are influenced by the hydrostatic effect, which might adversely impact the assessment of ischemia., Aims: This study aimed to investigate the impact of hydrostatic pressure on FFR measurements by correcting for the height and comparing FFR with [ 15 O]H 2 O positron emission tomography (PET)-derived relative flow reserve (RFR)., Methods: The 206 patients were included in this analysis. Patients underwent coronary computed tomography angiography (CCTA), [ 15 O]H 2 O PET, and invasive coronary angiography with routine FFR in every epicardial artery. Height differences between the aortic guiding catheter and distal pressure sensor were quantified on CCTA images. An FFR ≤ 0.80 was considered significant., Results: The study found a reclassification in 7% of the coronary arteries. Notably, 11% of left anterior descending (LAD) arteries were reclassified from hemodynamically significant to nonsignificant. Conversely, 6% of left circumflex (Cx) arteries were reclassified from nonsignificant to significant. After correcting for the hydrostatic pressure effect, the correlation between FFR and PET-derived RFR increased significantly from r = 0.720 to r = 0.786 (p = 0.009). The average magnitude of correction was +0.05 FFR units in the LAD, -0.03 in the Cx, and -0.02 in the right coronary artery., Conclusion: Hydrostatic pressure has a small but clinically relevant influence on FFR measurements obtained with a pressure wire. Correcting for this hydrostatic error significantly enhances the correlation between FFR and PET-derived RFR., (© 2024 The Author(s). Catheterization and Cardiovascular Interventions published by Wiley Periodicals LLC.)

Aims: The diagnostic performance of quantitative perfusion cardiac magnetic resonance (QP-CMR) imaging has scarcely been evaluated in patients with a history of coronary artery disease (CAD) and new onset chest pain. The present study compared the diagnostic performance of automated QP-CMR for detection of fractional flow reserve (FFR) defined hemodynamically significant CAD with visual assessment of first-pass stress perfusion CMR (v-CMR) and quantitative [15O]H2O positron emission tomography (PET) imaging in a true head-to-head fashion in patients with prior CAD., Methods and Results: This PACIFIC-2 substudy included 145 symptomatic chronic coronary symptom patients with prior myocardial infarction (MI) and/or percutaneous coronary intervention (PCI). All patients underwent dual-sequence, single bolus perfusion CMR and [15O]H2O PET perfusion imaging followed by invasive coronary angiography with three-vessel FFR. Hemodynamically significant CAD was defined as an FFR ≤0.80. QP-CMR, v-CMR and PET exhibited a sensitivity of 66%, 67%, and 80%, respectively, whereas specificity was 60%, 62%, and 63%. Sensitivity of QP-CMR was lower than PET (P=0.015), whereas specificity of QP-CMR and PET was comparable. Diagnostic accuracy and area under the curve (AUC) of QP-CMR (64% and 0.66) was comparable to both v-CMR (66% [P=NS] and 0.67 (P=NS]) and PET (74% [P=NS] and 0.78 [P=NS])., Conclusions: In patients with prior MI and/or PCI, the diagnostic performance of QP-CMR was comparable to visual assessment of first-pass stress perfusion CMR and quantitative [15O]H2O PET for the detection of hemodynamically significant CAD as defined by FFR., (© The Author(s) 2024. Published by Oxford University Press on behalf of the European Society of Cardiology.)

Background: The diagnostic performance of non-invasive imaging techniques for detecting obstructive coronary artery disease (CAD) in patients with a history of myocardial infarction or percutaneous coronary intervention has not been comprehensively evaluated. This meta-analysis assesses the diagnostic value of coronary CT angiography (CCTA), CCTA combined with CT perfusion (CCTA+CTP), cardiac MRI (CMR) and single-photon emission CT (SPECT) compared with invasive reference standards., Methods: We systematically searched PubMed, Embase, Web of Science and the Cochrane Library from 2005 to September 2022 for prospective, blinded studies including populations with ≥50% prior CAD., Results: We identified 18 studies encompassing 3265 patients, with obstructive CAD present in 64%. The per-patient sensitivity of CCTA (0.95; 95% CI 0.92 to 0.98), CCTA+CTP (0.93; 95% CI 0.84 to 0.98) and CMR (0.91; 95% CI 0.86 to 0.94) was high, while SPECT showed lower sensitivity (0.63; 95% CI 0.52 to 0.73). SPECT had higher specificity compared with CCTA (0.66; 95% CI 0.56 to 0.76 vs 0.37; 95% CI 0.29 to 0.46), but was comparable to CCTA+CTP (0.59; 95% CI 0.49 to 0.69) and CMR (0.69; 95% CI 0.53 to 0.81). The area under the curve for SPECT was the lowest (0.70; 95% CI 0.58 to 0.87), while CCTA (0.91; 95% CI 0.86 to 0.98), CCTA+CTP (0.89; 95% CI 0.73 to 1.00) and CMR (0.91; 95% CI 0.80 to 1.00) showed similar high values., Conclusions: In patients with prior CAD, CCTA, CCTA+CTP and CMR demonstrated high diagnostic performance, whereas SPECT had lower sensitivity. These findings can guide the selection of non-invasive imaging techniques in this high-risk population., Prospero Registration Number: CRD42022322348., Competing Interests: Competing interests: None declared., (© Author(s) (or their employer(s)) 2024. Re-use permitted under CC BY-NC. No commercial re-use. See rights and permissions. Published by BMJ.)

Aims: To investigate the location-specific prognostic significance of plaque burden, diameter stenosis and plaque morphology., Methods and Results: Patients without a documented cardiac history who underwent coronary computed tomography angiography (CCTA) for suspected coronary artery disease were included. Percentage atheroma volume (PAV), maximum diameter stenosis, and plaque morphology were assessed and classified into proximal, mid, or distal segments of the coronary tree. Major adverse cardiac events (MACE) were defined as death or non-fatal myocardial infarction. Among 2819 patients 267 events (9.5%) occurred during a median follow-up of 6.9 years. When adjusted for traditional risk factors and presence of PAV on other locations, only proximal PAV was independently associated with MACE. However, PAV of the proximal segments was strongly correlated to PAV localized at the mid (R= 0.76) and distal segments (R=0.74, p<0.01 for both). When only adjusted for cardiovascular risk factors, the area under the curve (AUC) to predict MACE for proximal PAV was 0.73 (95%CI 0.69-0.76), which was similar compared to mid PAV (AUC 0.72, 95%CI 0.68-0.76) and distal PAV (AUC 0.72, 95%CI 0.68-0.76). Similar results were obtained using diameter stenosis instead of PAV. The presence of proximal low-attenuation plaque had borderline additional prognostic value., Conclusions: Proximal PAV was the strongest predictor of MACE when adjusted for cardiovascular risk factors and plaque at other locations. However, when presence of plaque was only adjusted for cardiovascular risk factors, proximal, mid, and distal plaque localization showed a similar predictive ability for MACE., (© The Author(s) 2024. Published by Oxford University Press on behalf of the European Society of Cardiology. All rights reserved. For commercial re-use, please contact reprints@oup.com for reprints and translation rights for reprints. All other permissions can be obtained through our RightsLink service via the Permissions link on the article page on our site—for further information please contact journals.permissions@oup.com.)

Currently, cutoffs of quantitative [ 15 O]H 2 O PET to detect fractional flow reserve (FFR)-defined coronary artery disease (CAD) were derived from a single cohort that included patients without prior CAD. However, prior CAD, sex, and age can influence myocardial blood flow (MBF). Therefore, the present study determined the influence of prior CAD, sex, and age on optimal cutoffs of hyperemic MBF (hMBF) and coronary flow reserve (CFR) and evaluated whether cutoff optimization enhanced diagnostic performance of quantitative [ 15 O]H 2 O PET against an FFR reference standard. Methods: Patients with chronic coronary symptoms underwent [ 15 O]H 2 O PET and invasive coronary angiography with FFR. Optimal cutoffs for patients with and without prior CAD and subpopulations based on sex and age were determined. Results: This multicenter study included 560 patients. Optimal cutoffs were similar for patients with ( n = 186) and without prior CAD (hMBF, 2.3 vs. 2.3 mL·min -1 ·g -1 ; CFR, 2.7 vs. 2.6). Females ( n = 190) had higher hMBF cutoffs than males (2.8 vs. 2.3 mL·min -1 ·g -1 ), whereas CFRs were comparable (2.6 vs. 2.7). However, female sex-specific hMBF cutoff implementation decreased diagnostic accuracy as compared with the cutoff of 2.3 mL·min -1 ·g -1 (72% vs. 82%, P < 0.001). Patients aged more than 70 y ( n = 79) had lower hMBF (1.7 mL·min -1 ·g -1 ) and CFR (2.3) cutoffs than did patients aged 50 y or less, 51-60 y, and 61-70 y (hMBF, 2.3-2.4 mL·min -1 ·g -1 ; CFR, 2.7). Age-specific cutoffs in patients aged more than 70 y yielded comparable accuracy to the previously established cutoffs (hMBF, 72% vs. 76%, P = 0.664; CFR, 80% vs. 75%, P = 0.289). Conclusion: Patients with and without prior CAD had similar [ 15 O]H 2 O PET cutoffs for detecting FFR-defined significant CAD. Stratifying patients according to sex and age led to different optimal cutoffs; however, these values did not translate into an increased overall accuracy as compared with previously established thresholds for MBF., (© 2024 by the Society of Nuclear Medicine and Molecular Imaging.)

Background: Same-day discharge (SDD) in patients undergoing percutaneous coronary intervention (PCI) of a chronic total occlusion (CTO) is appealing because of the increased patient comfort. However, data on SDD following large-bore vascular access are scarce., Aims: We investigated the feasibility and safety of SDD in patients undergoing large-bore CTO PCI., Methods: Between 2013 and 2023, 948 patients were prospectively enrolled in a single-centre CTO registry and underwent CTO PCI. SDD was pursued in all patients. Large-bore access was defined as the use of ≥7 French (Fr) sheaths in ≥1 access site. A logistic regression analysis was used to identify predictors for non-SDD. Clinical follow-up was obtained at 30 days., Results: SDD was observed in 62% of patients. Large-bore access was applied in 99% of the cohort. SDD patients were younger and more often male, with lower rates of renal insufficiency and prior coronary artery bypass grafting. Local access site bleeding (odds ratio [OR] 8.53, 95% confidence interval [CI]: 5.24-13.87) and vascular access complications (OR 7.23, 95% CI: 1.98-26.32) made hospitalisation more likely, with vascular access complications occurring in 3%. At 30 days, the hospital readmission rate was low in both SDD and non-SDD patients (5% vs 7%; p=non-significant). Finally, SDD was not a predictor for major adverse cardiovascular events (MACE) at follow-up., Conclusions: Same-day discharge can be achieved in the majority of patients undergoing CTO PCI with large-bore (≥7 Fr) access. Similar low hospital readmission and MACE rates between SDD and non-SDD patients at 30 days demonstrate the feasibility and safety of SDD.

In patients evaluated for obstructive coronary artery disease (CAD), guidelines recommend using either fractional flow reserve (FFR) or instantaneous wave-free ratio (iFR) to guide coronary revascularization decision-making. The hemodynamic significance of lesions with discordant FFR and iFR measurements is debated. This study compared [ 15 O]H 2 O PET-derived absolute myocardial perfusion between vessels with concordant and discordant FFR and iFR measurements. Methods: We included 197 patients suspected of obstructive CAD who had undergone [ 15 O]H 2 O PET perfusion imaging and combined FFR/iFR interrogation in 468 vessels. Resting myocardial blood flow (MBF), hyperemic MBF, and coronary flow reserve (CFR) were compared among 4 groups: FFR low/iFR low ( n = 79), FFR high/iFR low ( n = 22), FFR low/iFR high ( n = 22), and FFR high/iFR high ( n = 345). Predefined [ 15 O]H 2 O PET thresholds for ischemia were 2.3 mL·min -1 ·g -1 or less for hyperemic MBF and 2.5 or less for CFR. Results: Hyperemic MBF was lower in the concordant low (2.09 ± 0.67 mL·min -1 ·g -1 ), FFR high/iFR low (2.41 ± 0.80 mL·min -1 ·g -1 ), and FFR low/iFR high (2.40 ± 0.69 mL·min -1 ·g -1 ) groups compared with the concordant high group (2.91 ± 0.84 mL·min -1 ·g -1 ) ( P < 0.001, P = 0.004, and P < 0.001, respectively). A lower CFR was observed in the concordant low (2.37 ± 0.76) and FFR high/iFR low (2.64 ± 0.84) groups compared with the concordant high group (3.35 ± 1.07, P < 0.01 for both). However, for vessels with either low FFR or low iFR, quantitative hyperemic MBF and CFR values exceeded the ischemic threshold in 38% and 49%, respectively. In addition, resting MBF exhibited a negative correlation with iFR ( P < 0.001) and was associated with FFR low/iFR high discordance compared with concordant low FFR/low iFR measurements, independent of clinical and angiographic characteristics, as well as hyperemic MBF (odds ratio [OR], 0.41; 95% CI, 0.26-0.65; P < 0.001). Conclusion: We found reduced myocardial perfusion in vessels with concordant low and discordant FFR/iFR measurements. However, FFR/iFR combinations often inaccurately classified vessels as either ischemic or nonischemic when compared with hyperemic MBF and CFR. Furthermore, a lower resting MBF was associated with a higher iFR and the occurrence of FFR low/iFR high discordance. Our study showed that although combined FFR/iFR assessment can be useful to estimate the hemodynamic significance of coronary lesions, these pressure-derived indices provide a limited approximation of [ 15 O]H 2 O PET-derived quantitative myocardial perfusion as the physiologic standard of CAD severity., (© 2024 by the Society of Nuclear Medicine and Molecular Imaging.)

Aims: In chronic coronary syndrome (CCS) patients with documented coronary artery disease (CAD), ischaemia detection by myocardial perfusion imaging (MPI) and an invasive approach are viable diagnostic strategies. We compared the diagnostic performance of quantitative flow ratio (QFR) with single-photon emission computed tomography (SPECT), positron emission tomography (PET), and cardiac magnetic resonance imaging (CMR) in patients with prior CAD [previous percutaneous coronary intervention (PCI) and/or myocardial infarction (MI)]., Methods and Results: This PACIFIC-2 sub-study evaluated 189 CCS patients with prior CAD for inclusion. Patients underwent SPECT, PET, and CMR followed by invasive coronary angiography with fractional flow reserve (FFR) measurements of all major coronary arteries (N = 567), except for vessels with a sub-total or chronic total occlusion. Quantitative flow ratio computation was attempted in 488 (86%) vessels with measured FFR available (FFR ≤0.80 defined haemodynamically significant CAD). Quantitative flow ratio analysis was successful in 334 (68%) vessels among 166 patients and demonstrated a higher accuracy (84%) and sensitivity (72%) compared with SPECT (66%, P < 0.001 and 46%, P = 0.001), PET (65%, P < 0.001 and 58%, P = 0.032), and CMR (72%, P < 0.001 and 33%, P < 0.001). The specificity of QFR (87%) was similar to that of CMR (83%, P = 0.123) but higher than that of SPECT (71%, P < 0.001) and PET (67%, P < 0.001). Lastly, QFR exhibited a higher area under the receiver operating characteristic curve (0.89) than SPECT (0.57, P < 0.001), PET (0.66, P < 0.001), and CMR (0.60, P < 0.001)., Conclusion: QFR correlated better with FFR in patients with prior CAD than MPI, as reflected in the higher diagnostic performance measures for detecting FFR-defined, vessel-specific, significant CAD., Competing Interests: Conflict of interests: J.H.R., R.A.K., and J.T. are employees of Medis Medical Imaging. J.K. received consultancy fees from GE Healthcare and AstraZeneca and speaker fees from GE Healthcare, Bayer, Lundbeck, and Merck. P.K. received research grants from HeartFlow Inc. All others have no conflict of interests to disclose., (© The Author(s) 2023. Published by Oxford University Press on behalf of the European Society of Cardiology.)

Aims: Coronary flow capacity (CFC) integrates quantitative hyperaemic myocardial blood flow (hMBF) and coronary flow reserve (CFR) to comprehensively assess physiological severity of coronary artery disease (CAD). This study evaluated the effects of revascularization on CFC as assessed by serial [15O]H2O positron emission tomography (PET) perfusion imaging., Methods and Results: A total of 314 patients with stable CAD underwent [15O]H2O PET imaging at baseline and after myocardial revascularization to assess changes in hMBF, CFR, and CFC in 415 revascularized vessels. Using thresholds for ischaemia and normal perfusion, vessels were stratified in five CFC categories: myocardial steal, severely reduced CFC, moderately reduced CFC, minimally reduced CFC, and normal flow. Additionally, the association between CFC increase and the composite endpoint of death and non-fatal myocardial infarction (MI) was studied. Vessel-specific CFC improved after revascularization (P < 0.01). Furthermore, baseline CFC was an independent predictor of CFC increase (P < 0.01). The largest changes in ΔhMBF (0.90 ± 0.74, 0.93 ± 0.65, 0.79 ± 0.74, 0.48 ± 0.61, and 0.29 ± 0.66 mL/min/g) and ΔCFR (1.01 ± 0.88, 0.99 ± 0.69, 0.87 ± 0.88, 0.66 ± 0.91, and -0.01 ± 1.06) were observed in vessels with lower baseline CFC (P < 0.01 for both). During a median follow-up of 3.5 (95% CI 3.1-3.9) years, an increase in CFC was independently associated with lower rates of death and non-fatal MI (HR 0.43, 95% CI 0.19-0.98, P = 0.04)., Conclusion: Successful revascularization results in an increase in CFC. Furthermore, baseline CFC was an independent predictor of change in hMBF, CFR, and subsequently CFC. In addition, an increase in CFC was associated with a favourable outcome in terms of death and non-fatal MI., (© The Author(s) 2021. Published by Oxford University Press on behalf of the European Society of Cardiology.)