Dynamic Stress Computed Tomography Perfusion With a Whole-Heart Coverage Scanner in Addition to Coronary Computed Tomography Angiography and Fractional Flow Reserve Computed Tomography Derived

ObjectivesThe aims of the study were to test the diagnostic accuracy of integrated evaluation of dynamic myocardial computed tomography perfusion (CTP) on top of coronary computed tomography angiography (cCTA) plus fractional flow reserve computed tomography derived (FFR_CT) by using a whole-heart coverage computed tomography (CT) scanner as compared with clinically indicated invasive coronary angiography (ICA) and invasive fractional flow reserve (FFR).BackgroundRecently, new techniques such as dynamic stress computed tomography perfusion (stress-CTP) emerged as potential strategies to combine anatomical and functional evaluation in a one-shot scan. However, previous experiences with this technique were associated with high radiation exposure.MethodsEighty-five consecutive symptomatic patients scheduled for ICA were prospectively enrolled. All patients underwent rest cCTA followed by stress dynamic CTP with a whole-heart coverage CT scanner (Revolution CT, GE Healthcare, Milwaukee, Wisconsin). FFR_CT was also measured by using the rest cCTA dataset. The diagnostic accuracy to detect functionally significant coronary artery disease (CAD) in a vessel-based model of cCTA alone, cCTA+FFR_CT, cCTA+CTP, or cCTA+FFR_CT+CTP were assessed and compared by using ICA and invasive FFR as reference. The overall effective dose of dynamic CTP was also measured.ResultsThe prevalence of obstructive CAD and functionally significant CAD was 77% and 57%, respectively. The sensitivity and specificity of cCTA alone, cCTA+FFR_CT, and cCTA+CTP were 83% and 66%, 86% and 75%, and 73% and 86%, respectively. Both the addition of FFR_CT and CTP improves the area under the curve (AUC: 0.876 and 0.878, respectively) as compared with cCTA alone (0.826; p < 0.05). The sequential strategy of cCTA+FFR_CT+CTP showed the highest AUC (0.919; p < 0.05) as compared with all other strategies. The mean effective radiation dose (ED) for cCTA and stress CTP was 2.8 ± 1.2 mSv and 5.3 ± 0.7 mSv, respectively.ConclusionsThe addition of dynamic stress CTP on top of cCTA and FFR_CT provides additional diagnostic accuracy with acceptable radiation exposure.     

Prognostic Value of Computed Tomography-Derived Fractional Flow Reserve Comparison With Myocardial Perfusion Imaging

ObjectivesThe aim of this study was to compare the incremental prognostic value of coronary computed tomography (CT) angiography (CCTA)-derived machine learning fractional flow reserve CT (ML-FFRct) versus that of ischemia detected on single-photon emission-computed tomography (SPECT) myocardial perfusion imaging (MPI) on incident cardiovascular outcomes.BackgroundSPECT MPI and ML-FFRct are noninvasive tools that can assess the hemodynamic significance of coronary atherosclerotic disease.MethodsWe studied a retrospective cohort of consecutive patients who underwent clinically indicated CCTA and SPECT MPI. ML-FFRct was computed using a ML prototype. The primary outcome was all-cause mortality and nonfatal myocardial infarction (D/MI), and the secondary outcome was D/MI and unplanned revascularization, percutaneous coronary intervention (PCI) or coronary artery bypass graft (CABG) occurring more than 90 days postimaging. Multiple nested multivariate cox regression was used to model a scenario wherein an initial anatomical assessment was followed by a functional assessment.ResultsA total of 471 patients (mean age: 64 ± 13 year; 53% males) were included. Comorbidities were prevalent (78% hypertension, 66% diabetes, 81% dyslipidemia). ML-FFRct was <0.8 in at least 1 proximal/midsegment was present in 41.6% of patients, and ischemia on MPI was present in 13.8%. After a median follow-up of 18 months, 7% of patients (n = 33) experienced D/MI. On multivariate Cox proportional analysis, the presence of ischemia on MPI but not ML-FFRct significantly predicted D/MI (HR: 2.3; 95% CI: 1.0-5.0; P = 0.047; or HR: 0.7; 95% CI: 0.3-1.4; P = 0.306 respectively) when added to CCTA obstructive stenosis. Furthermore, the model with SPECT ischemia had higher global chi-square result and significantly improved reclassification. Results were similar using the secondary outcome and on several sensitivity analyses.ConclusionsIn a high-risk patient cohort, SPECT MPI but not ML-FFRct adds independent and incremental prognostic information to CCTA-based anatomical assessment and clinical risk factors in predicting incident outcomes.     

Prognostic Value of Stress CMR Perfusion Imaging in Patients With Reduced Left Ventricular Function

ObjectivesThe aim of this study was to investigate the prognostic value of stress cardiac magnetic resonance imaging (CMR) in patients with reduced left ventricular (LV) systolic function.BackgroundPatients with ischemic cardiomyopathy are at risk from both myocardial ischemia and heart failure. Invasive testing is often used as the first-line investigation, and there is limited evidence as to whether stress testing can effectively provide risk stratification.MethodsIn this substudy of a multicenter registry from 13 U.S. centers, patients with reduced LV ejection fraction (<50%), referred for stress CMR for suspected myocardial ischemia, were included. The primary outcome was cardiovascular death or nonfatal myocardial infarction. The secondary outcome was a composite of cardiovascular death, nonfatal myocardial infarction, hospitalization for unstable angina or congestive heart failure, and unplanned late coronary artery bypass graft surgery.ResultsAmong 582 patients (mean age 62 ± 12 years, 34% women), 40% had a history of congestive heart failure, and the median LV ejection fraction was 39% (interquartile range: 28% to 45%). At median follow-up of 5.0 years, 97 patients had experienced the primary outcome, and 182 patients had experienced the secondary outcome. Patients with no CMR evidence of ischemia or late gadolinium enhancement (LGE) experienced an annual primary outcome event rate of 1.1%. The presence of ischemia, LGE, or both was associated with higher event rates. In a multivariate model adjusted for clinical covariates, ischemia and LGE were independent predictors of the primary (hazard ratio [HR]: 2.63; 95% confidence interval [CI]: 1.68 to 4.14; p < 0.001; and HR: 1.86; 95% CI: 1.05 to 3.29; p = 0.03) and secondary (HR: 2.14; 95% CI: 1.55 to 2.95; p < 0.001; and HR 1.70; 95% CI: 1.16 to 2.49; p = 0.007) outcomes. The addition of ischemia and LGE led to improved model discrimination for the primary outcome (change in C statistic from 0.715 to 0.765; p = 0.02). The presence and extent of ischemia were associated with higher rates of use of downstream coronary angiography, revascularization, and cost of care spent on ischemia testing.ConclusionsStress CMR was effective in risk-stratifying patients with reduced LV ejection fractions. (Stress CMR Perfusion Imaging in the United States [SPINS] Study; NCT03192891)     

Prognostic Value of Vasodilator Stress Perfusion Cardiovascular Magnetic Resonance in Patients With Prior Myocardial Infarction

ObjectivesThis study sought to assess the incremental prognostic value of vasodilator stress cardiovascular magnetic resonance (CMR) in patients with prior myocardial infarction (MI).BackgroundRecurrent MI is a major cause of mortality and morbidity among MI survivors.MethodsBetween 2008 and 2019, consecutive patients with prior MI referred for stress CMR were followed up for the occurrence of major adverse cardiovascular events (MACE), defined by cardiovascular mortality or recurrent nonfatal MI. Uni- and multivariable Cox regressions were performed to determine the prognostic value of inducible ischemia and the extent of myocardial scar.ResultsAmong 1,594 patients with prior MI and myocardial scar on CMR, 1,401 (92%) (68.2 ± 11.0 years; 61.4% men) completed the follow-up (median: 6.2 years), and 205 had MACE (14.6%). Patients without inducible ischemia experienced a lower annual rate of MACE (3.1%) than those with 1–2 (4.9%), 3–5 (21.5%), or ≥6 segments of ischemia (45.7%) (all p < 0.01). Using Kaplan-Meier analysis, the presence of inducible ischemia and the extent of scar were associated with MACE (hazard ratio [HR]:3.52; 95% confidence interval [CI]: 2.67 to 4.65 and HR: 1.66; 95% CI: 1.53 to 2.18, respectively; both p < 0.001). In multivariable stepwise Cox regression, the presence of ischemia and the extent of scar were independent predictors of MACE (HR: 2.84; 95% CI: 2.14 to 3.78 and HR: 1.57; 95% CI: 1.44 to 1.72, respectively; both p < 0.001). These findings were significant in both symptomatic and asymptomatic patients. The addition of CMR parameters to the model including traditional risk factors resulted in a better discrimination for MACE (C-statistic: 0.76 vs. 0.62).ConclusionsIn patients with prior MI, vasodilator stress CMR has independent and incremental prognostic value over traditional risk factors.     

Prognostic Value of Computed Tomography–Derived Extracellular Volume in TAVR Patients With Low-Flow Low-Gradient Aortic Stenosis

ObjectivesThe association between extracellular volume (ECV) measured by computed tomography angiography (CTA) and clinical outcomes was evaluated in low-flow low-gradient (LFLG) aortic stenosis (AS) patients undergoing transcatheter aortic valve replacement (TAVR).BackgroundPatients with LFLG AS comprise a high-risk group with respect to clinical outcomes. Although ECV, a marker of myocardial fibrosis, is traditionally measured with cardiac magnetic resonance, it can also be measured using cardiac CTA. The authors hypothesized that in LFLG AS, increased ECV may be associated with adverse clinical outcomes.MethodsIn 150 LFLG patients with AS who underwent TAVR, ECV was quantified using pre-TAVR CTA. Echocardiographic and clinical information including all-cause death and heart failure rehospitalization (HFH) was obtained from electronic medical records. A Cox proportional hazards model was used to evaluate the association between ECV and death+HFH.ResultsDuring a median follow-up of 13.9 months (range 0.07 to 28.9 months), there were 31 death+HFH events (21%). Patients who experienced death+HFH had a greater median Society of Thoracic Surgery score (9.9 vs. 4.7; p < 0.01), lower left ventricular ejection fraction (42.3 ± 20.2% vs. 52.7 ± 17.2%; p < 0.01), lower mean transvalvular gradient (24.9 ± 8.9 mm Hg vs. 28.1 ± 7.3 mm Hg; p = 0.04) and increased mean ECV (35.5 ± 9.6% vs. 29.9 ± 8.2%; p < 0.01) compared with patients who did not experience death+HFH. In a multivariable Cox proportional hazards model, increase in ECV was associated with increase in death+HFH, (hazard ratio per 1% increase: 1.04, 95% confidence interval: 1.01 to 1.09; p < 0.01).ConclusionsIn patients with LFLG AS, CTA measured increase in ECV is associated with increased risk of adverse clinical outcomes post-TAVR and may thus serve as a useful noninvasive marker for prognostication.     

Feasibility and Prognostic Value of Vasodilator Stress Perfusion CMR in Patients With Atrial Fibrillation

ObjectivesThe aim of this study was to assess the feasibility and prognostic value of vasodilator stress perfusion cardiovascular magnetic resonance (CMR) in patients with atrial fibrillation (AF).BackgroundBecause most studies have excluded arrhythmic patients, the prognostic value of stress perfusion CMR in patients with AF is unknown.MethodsBetween 2008 and 2018, consecutive patients with suspected or stable chronic coronary artery disease and AF referred for vasodilator stress perfusion CMR were included and followed for the occurrence of major adverse cardiovascular event(s) (MACE), defined as cardiovascular death or nonfatal myocardial infarction. The diagnosis of AF was defined by 12-lead electrocardiography before and after CMR. Univariate and multivariate Cox regressions were performed to determine the prognostic value of inducible ischemia or late gadolinium enhancement (LGE) by CMR.ResultsOf 639 patients (mean age 72 ± 9 years, 77% men), 602 (94%) completed the CMR protocol, and 538 (89%) completed follow-up (median 5.1 years); 80 had MACE. Using Kaplan-Meier analysis, the presence of ischemia (hazard ratio [HR]: 7.56; 95% confidence interval [CI]: 4.86 to 11.80) or LGE (HR: 2.41; 95% CI: 1.55 to 3.74) was associated with the occurrence of MACE (p < 0.001 for both). In a multivariate Cox regression including clinical and CMR indexes, the presence of ischemia (HR: 5.98; 95% CI: 3.68 to 9.73) or LGE (HR: 2.61; 95% CI: 1.89 to 3.60) was an independent predictor of MACE (p < 0.001 for both).ConclusionsIn patients with AF, stress perfusion CMR is feasible and has good discriminative prognostic value to predict the occurrence of MACE.     

Prediction of Coronary Revascularization in Stable Angina: Comparison of FFRCT With CMR Stress Perfusion Imaging

ObjectivesThis study was designed to compare head-to-head fractional flow reserve (FFR) derived from coronary computed tomography angiography (CTA) (FFR_CT) and cardiac magnetic resonance (CMR) stress perfusion imaging for prediction of standard-of-care–guided coronary revascularization in patients with stable chest pain and obstructive coronary artery disease by coronary CTA.BackgroundFFR_CT is a novel modality for noninvasive functional testing. The clinical utility of FFR_CT compared to CMR stress perfusion imaging in symptomatic patients with coronary artery disease is unknown.MethodsProspective study of patients (n = 110) with stable angina pectoris and 1 or more coronary stenosis ≥50% by coronary CTA. All patients underwent invasive coronary angiography. Revascularization was FFR-guided in stenoses ranging from 30% to 90%. FFR_CT ≤0.80 in 1 or more coronary artery or a reversible perfusion defect (≥2 segments) by CMR categorized patients with ischemia. FFR_CT and CMR were analyzed by core laboratories blinded for patient management.ResultsA total of 38 patients (35%) underwent revascularization. Per-patient diagnostic performance for identifying standard-of-care–guided revascularization, (95% confidence interval) yielded a sensitivity of 97% (86% to 100%) for FFR_CT versus 47% (31% to 64%) for CMR, p < 0.001; corresponding specificity was 42% (30% to 54%) versus 88% (78% to 94%), p < 0.001; negative predictive value of 97% (91% to 100%) versus 76% (67% to 85%), p < 0.05; positive predictive value of 47% (36% to 58%) versus 67% (49% to 84%), p < 0.05; and accuracy of 61% (51% to 70%) versus 74% (64% to 82%), p > 0.05, respectively.ConclusionsIn patients with stable chest pain referred to invasive coronary angiography based on coronary CTA, FFR_CT and CMR yielded similar overall diagnostic accuracy. Sensitivity for prediction of revascularization was highest for FFR_CT, whereas specificity was highest for CMR.     

Prognostic Value of Stress CMR in Symptomatic Patients With Coronary Stenosis on CCTA

BackgroundNoninvasive functional imaging is often performed in patients with obstructive coronary artery disease (CAD) on coronary computed tomography angiography (CTA). However, the prognostic value of stress cardiac magnetic resonance (CMR) is unknown in patients with coronary stenosis of unknown significance on coronary CTA.ObjectivesThis study assessed the prognostic value of stress CMR in symptomatic patients with obstructive CAD of unknown significance on coronary CTA.MethodsBetween 2008 and 2020, consecutive symptomatic patients without known CAD referred for coronary CTA were screened. Patients with obstructive CAD (at least 1 ≥50% stenosis on coronary CTA) were further referred for stress CMR and followed for the occurrence of major adverse cardiovascular events (MACEs), defined as cardiovascular death or nonfatal myocardial infarction.ResultsOf 2,210 patients who completed CMR, 2,038 (46.5% men; mean age 69.8 ± 12.2 years) completed follow-up (median 6.8 years; IQR: 5.9-9.2 years); 281 experienced a MACE (13.8%). Inducible ischemia and late gadolinium enhancement (LGE) were significantly associated with MACEs (HR: 4.51 [95% CI: 3.55-5.74], and HR: 3.32 [95% CI: 2.55-4.32], respectively; P < 0.001). In multivariable Cox regression, the number of segments with >70% stenosis, with noncalcified plaques and the number of vessels with obstructive CAD were prognosticators (P < 0.001). The presence of inducible ischemia and LGE were independent predictors of MACEs (HR: 3.97 [95% CI: 3.43-5.13]; HR: 2.30 [95% CI: 1.52-3.33]; P < 0.001). After adjustment, stress CMR showed the best improvement in model discrimination and reclassification above traditional risk factors and coronary CTA (C-statistic improvement: 0.04; net reclassification improvement = 0.421; integrative discrimination index = 0.047).ConclusionsIn symptomatic patients with obstructive CAD of unknown significance on coronary CTA, stress CMR had incremental prognostic value to predict MACEs.     

Prognostic Value of Stress Cardiac Magnetic Resonance in Patients With Known Coronary Artery Disease

ObjectivesThis study sought to determine whether stress cardiac magnetic resonance (CMR) provides clinically relevant risk reclassification in patients with known coronary artery disease (CAD) in a multicenter setting in the United States.BackgroundDespite improvements in medical therapy and coronary revascularization, patients with previous CAD account for a disproportionately large portion of CV events and pose a challenge for noninvasive stress testing.MethodsFrom the Stress Perfusion Imaging in the United States (SPINS) registry, we identified consecutive patients with documented CAD who were referred to stress CMR for evaluation of myocardial ischemia. The primary outcome was nonfatal myocardial infarction (MI) or cardiovascular (CV) death. Major adverse CV events (MACE) included MI/CV death, hospitalization for heart failure or unstable angina, and late unplanned coronary artery bypass graft. The prognostic association and net reclassification improvement by ischemia for MI/CV death were determined.ResultsOut of 755 patients (age 64 ± 11 years, 64% male), we observed 97 MI/CV deaths and 210 MACE over a median follow-up of 5.3 years. Presence of ischemia demonstrated a significant association with MI/CV death (HR: 2.30; 95% CI: 1.54-3.44; P < 0.001) and MACE (HR: 2.24 ([95% CI: 1.69-2.95; P < 0.001). In a multivariate model adjusted for CV risk factors, ischemia maintained strong association with MI/CV death (HR: 1.84; 95% CI: 1.17-2.88; P = 0.008) and MACE (HR: 1.77; 95% CI: 1.31-2.40; P < 0.001) and reclassified 95% of patients at intermediate pretest risk (62% to low risk, 33% to high risk) with corresponding changes in the observed event rates of 1.4% and 5.3% per year for low and high post-test risk, respectively.ConclusionsIn a multicenter cohort of patients with known CAD, CMR-assessed ischemia was strongly associated with MI/CV death and reclassified patient risk beyond CV risk factors, especially in those considered to be at intermediate risk. Absence of ischemia was associated with a <2% annual rate of MI/CV death. (Stress CMR Perfusion Imaging in the United States [SPINS] Study; NCT03192891)     

Superior Risk Stratification With Coronary Computed Tomography Angiography Using a Comprehensive Atherosclerotic Risk Score

ObjectivesThis study was designed to assess the prognostic value of a new comprehensive coronary computed tomography angiography (CTA) score compared with the stenosis severity component of the Coronary Artery Disease-Reporting and Data System (CAD-RADS).BackgroundCurrent risk assessment with coronary CTA is mainly focused on maximal stenosis severity. Integration of plaque extent, location, and composition in a comprehensive model may improve risk stratification.MethodsA total of 2,134 patients with suspected but without known CAD were included. The predictive value of the comprehensive CTA score (ranging from 0 to 42 and divided into 3 groups: 0 to 5, 6 to 20, and >20) was compared with the CAD-RADS combined into 3 groups (0% to 30%, 30% to 70% and ≥70% stenosis). Its predictive performance was internally and externally validated (using the 5-year follow-up dataset of the CONFIRM [Coronary CT Angiography Evaluation for Clinical Outcomes: An International Multicenter Registry], n = 1,971).ResultsThe mean age of patients was 55 ± 13 years, mean follow-up 3.6 ± 2.8 years, and 130 events (myocardial infarction or death) occurred. The new, comprehensive CTA score showed strong and independent predictive value using the Cox proportional hazard analysis. A model including clinical variables plus comprehensive CTA score showed better discrimination of events compared with a model consisting of clinical variables plus CAD-RADS (0.768 vs. 0.742, p = 0.001). Also, the comprehensive CTA score correctly reclassified a significant proportion of patients compared with the CAD-RADS (net reclassification improvement 12.4%, p < 0.001). Good predictive accuracy was reproduced in the external validation cohort.ConclusionsThe new comprehensive CTA score provides better discrimination and reclassification of events compared with the CAD-RADS score based on stenosis severity only. The score retained similar prognostic accuracy when externally validated. Anatomic risk scores can be improved with the addition of extent, location, and compositional measures of atherosclerotic plaque. (Comprehensive CTA risk score calculator is available at: http://18.224.14.19/calcApp/)     

Worldwide Diagnostic Reference Levels for Single-Photon Emission Computed Tomography Myocardial Perfusion Imaging: Findings From INCAPS

ObjectivesThis study sought to establish worldwide and regional diagnostic reference levels (DRLs) and achievable administered activities (AAAs) for single-photon emission computed tomography (SPECT) myocardial perfusion imaging (MPI).BackgroundReference levels serve as radiation dose benchmarks to compare individual laboratories against aggregated data, helping to identify sites in greatest need of dose reduction interventions. DRLs for SPECT MPI have previously been derived from national or regional registries. To date there have been no multiregional reports of DRLs for SPECT MPI from a single standardized dataset.MethodsData were submitted voluntarily to the INCAPS (International Atomic Energy Agency Nuclear Cardiology Protocols Study), a cross-sectional, multinational registry of MPI protocols. A total of 7,103 studies were included. DRLs and AAAs were calculated by protocol for each world region and for aggregated worldwide data.ResultsThe aggregated worldwide DRLs for rest-stress or stress-rest studies employing technetium Tc 99m–labeled radiopharmaceuticals were 11.2 mCi (first dose) and 32.0 mCi (second dose) for 1-day protocols, and 23.0 mCi (first dose) and 24.0 mCi (second dose) for multiday protocols. Corresponding AAAs were 10.1 mCi (first dose) and 28.0 mCi (second dose) for 1-day protocols, and 17.8 mCi (first dose) and 18.7 mCi (second dose) for multiday protocols. For stress-only technetium Tc 99m studies, the worldwide DRL and AAA were 18.0 mCi and 12.5 mCi, respectively. Stress-first imaging was used in 26% to 92% of regional studies except in North America where it was used in just 7% of cases. Significant differences in DRLs and AAAs were observed between regions.ConclusionsThis study reports reference levels for SPECT MPI for each major world region from one of the largest international registries of clinical MPI studies. Regional DRLs may be useful in establishing or revising guidelines or simply comparing individual laboratory protocols to regional trends. Organizations should continue to focus on establishing standardized reporting methods to improve the validity and comparability of regional DRLs.     

Stress Myocardial Blood Flow Ratio by Dynamic CT Perfusion Identifies Hemodynamically Significant CAD

ObjectivesThe aim of this study was to evaluate the diagnostic accuracy of stress myocardial blood flow ratio (SFR), a novel parameter derived from stress dynamic computed tomographic perfusion (CTP), for the detection of hemodynamically significant coronary stenosis.BackgroundA comprehensive cardiac computed tomographic protocol combining coronary computed tomographic angiography (CTA) and CTP can provide a simultaneous assessment of both coronary artery anatomy and ischemia.MethodsPatients with chest pain scheduled for invasive angiography were prospectively enrolled in this study. Stress dynamic CTP was performed followed by coronary CTA using a second-generation dual-source computed tomographic system. At subsequent invasive angiography, fractional flow reserve was performed to identify hemodynamically significant stenosis. For each coronary territory, SFR was defined as the ratio of hyperemic myocardial blood flow (MBF) in an artery with stenosis to hyperemic MBF in a nondiseased artery. The diagnostic accuracy of SFR to identify hemodynamically significant stenosis was determined against the reference standard of invasive fractional flow reserve ≤0.80.ResultsA total of 82 patients (mean age 58.5 ± 10 years) with 101 vessels with either 1- or 2-vessel disease were included. By FFR, 48 (47.5%) vessels were deemed hemodynamically significant. Hyperemic MBF and SFR were lower for vessels with hemodynamically significant lesions (95.1 ± 32.4 ml/100 ml/min vs. 142.5 ± 31.2 ml/100 ml/min and 0.66 ± 0.14 vs. 0.90 ± 0.07, respectively; p < 0.01 for both). When compared with ≥50% stenosis by CTA, the specificity for detecting ischemia by SFR increased from 43% to 91%, while the sensitivity decreased from 95% to 62%. Accordingly, the positive and negative predictive values were 85% and 73%, respectively. The combination of stenosis ≥50% by CTA and SFR resulted in an area under the curve of 0.91, which was significantly higher compared with hyperemic MBF (area under the curve = 0.79; p = 0.013).ConclusionsCalculation of SFR by dynamic CTP provides a novel and accurate method to identify flow-limiting coronary stenosis.     

Implementing Coronary Computed Tomography Angiography in the Catheterization Laboratory

Coronary computed tomography angiography (CCTA) is now an established tool in the diagnostic work-up of patients suspected to have coronary artery disease. Yet, its usefulness beyond this phase has not been fully explored. The current review focuses on the implementation of CCTA as a tool to plan and guide coronary interventions in the catheterization laboratory. Specifically, we explore the potential of CCTA to improve patient selection for percutaneous revascularization, provide the rationale for better resource use, and present a novel approach to incorporate 3-dimensional CT guidance for percutaneous coronary interventions.     

Sex Differences in Coronary Computed Tomography Angiography–Derived Fractional Flow Reserve: Lessons From ADVANCE

ObjectivesThis study is to determine the management and clinical outcomes of patients investigated with coronary computed tomography angiography (CCTA)–derived fractional flow reserve (FFR_CT) according to sex.BackgroundWomen are underdiagnosed with conventional ischemia testing, have lower rates of obstructive coronary artery disease (CAD) at invasive coronary angiography (ICA), yet higher mortality compared to men. Whether FFR_CT improves sex-based patient management decisions compared to CCTA alone is unknown.MethodsSubjects with symptoms and CAD on CCTA were enrolled (2015 to 2017). Demographics, symptom status, CCTA anatomy, coronary volume to myocardial mass ratio (V/M), lowest FFR_CT values, and management plans were captured. Endpoints included reclassification rate between CCTA and FFR_CT management plans, incidence of ICA demonstrating obstructive CAD (≥50% stenosis) and revascularization rates.ResultsA total of 4,737 patients (n = 1,603 females, 33.8%) underwent CCTA and FFR_CT. Women were older (age 68 ± 10 years vs. 65 ± 10 years; p < 0.0001) with more atypical symptoms (41.5% vs. 33.9%; p < 0.0001). Women had less obstructive CAD (65.4% vs. 74.7%; p < 0.0001) at CCTA, higher FFR_CT (0.76 ± 0.10 vs. 0.73 ± 0.10; p < 0.0001), and lower likelihood of positive FFR_CT ≤ 0.80 for the same degree stenosis (p < 0.0001). A positive FFR_CT ≤0.80 resulted in equal referral to ICA (n = 510 [54.5%] vs. n = 1,249 [56.5%]; p = 0.31), but more nonobstructive CAD (n = 208 [32.1%] vs. n = 354 [24.5%]; p = 0.0003) and less revascularization (n = 294 [31.4%] vs. n = 800 [36.2%]; p < 0.0001) in women, unless the FFR_CT was ≤0.75 where revascularization rates were similar (n = 253 [41.9%] vs. n = 715 [46.4%]; p = 0.06). Women have a higher V/M ratio (26.17 ± 7.58 mm³/g vs. 24.76 ± 7.22 mm³/g; p < 0.0001) that is associated with higher FFR_CT independent of degree stenosis (p < 0.001). Predictors of revascularization included stenosis severity, FFR_CT, symptoms, and V/M ratio (p < 0.001) but not female sex (p = 0.284).ConclusionsFFR_CT differs between the sexes, as women have a higher FFR_CT for the same degree of stenosis. In FFR_CT-positive CAD, women have less obstructive CAD at ICA and less revascularization, which is associated with higher V/M ratio. The findings suggest that CAD and FFR_CT variations by sex need specific interpretation as these differences may affect therapeutic decision making and clinical outcomes. (Assessing Diagnostic Value of Non-invasive FFRCT in Coronary Care [ADVANCE]; NCT02499679)     

Long-Term Prognosis of Patients With Coronary Microvascular Disease Using Stress Perfusion Cardiac Magnetic Resonance

ObjectivesThis study investigated the prognosis of coronary microvascular disease (CMD) as determined by stress perfusion cardiac magnetic resonance (CMR) in patients with ischemic symptoms but without significant coronary artery disease (CAD).BackgroundPatients with CMD have poorer prognosis with various cardiac diseases. The myocardial perfusion reserve index (MPRI) derived from noninvasive stress perfusion CMR has been established to diagnose microvascular angina with a threshold MPRI <1.4. The prognosis of CMD as determined by MPRI is unknown.MethodsChest pain patients without epicardial CAD or myocardial disease from January 2009 to December 2017 were retrospectively included from 3 imaging centers in Hong Kong (HK). Stress perfusion CMR examinations were performed using either adenosine or adenosine triphosphate. Adequate stress was assessed by achieving splenic switch-off sign. Measurement of MPRI was performed in all stress perfusion CMR scans. Patients were followed for major adverse cardiovascular events defined as all-cause death, acute coronary syndrome (ACS), epicardial CAD development, heart failure hospitalization and non-fatal stroke.ResultsA total of 218 patients were studied (mean age 59 ± 12 years; 49.5% male) and the average MPRI of that cohort was 1.56 ± 0.33. Females and a history of hyperlipidemia were predictors of lower MPRI. Major adverse cardiovascular events (MACE) occurred in 15.6% of patients during a median follow-up of 5.5 years (interquartile range: 4.6 to 6.8 years). The optimal cutoff value of MPRI in predicting MACE was found with a threshold MPRI ≤1.47. Patients with MPRI ≤1.47 had three-fold increased risk of MACE compared with those with MPRI >1.47 (hazard ratio [HR]: 3.14; 95% confidence interval [CI]: 1.58 to 6.25; p = 0.001). Multivariate Cox regression after adjusting for age and hypertension demonstrated that MPRI was an independent predictor of MACE (HR: 0.10; 95% CI: 0.03 to 0.34; p < 0.001).ConclusionsStress perfusion CMR-derived MPRI is an independent imaging marker that predicts MACE in patients with ischemic symptom and no overt CAD over the medium term.     

Coronary Access After TAVR With a Self-Expanding Bioprosthesis: Insights From Computed Tomography

ObjectivesThe authors sought to estimate possible interference of the Medtronic Evolut R/Pro transcatheter heart valve (THV) frame with coronary access using multislice computed tomography (MSCT) data.BackgroundLower-risk patients undergoing transcatheter aortic valve replacement (TAVR) endure a high cumulative risk of coronary events, but coronary access can be challenging.MethodsIn 101 patients who received an Evolut R/Pro THV, post-TAVR MSCT (performed at a median of 30 days after TAVR) was used to assess possible interference of the elements of the THV frame with coronary access.ResultsThe closest cell of the THV frame vertically aligned with the coronary ostium was located opposite the ostium in 58% and 63%, below the ostium in 22% and 30%, or above the ostium in 20% and 7% of left and right coronary arteries, respectively. The free sinus of Valsalva space between the THV frame and the coronary ostium was 0.45 ± 0.17 cm and 0.44 ± 0.17 cm for the left and right coronary arteries, respectively, and showed a stepwise decrease with decreasing THV size (p < 0.001). Bioprosthetic valve commissures were antianatomic (i.e., not aligned with native commissures) in 45 patients (47%), and the commissural post was overlapping a coronary ostium in 15 patients (16%). Two patients (2.0%) had a possible interference of the paravalvular sealing skirt with coronary access.ConclusionsUsing post-TAVR MSCT data, the main mechanism of potential interference of Evolut R/Pro frame with coronary access was an antianatomic commissural post overlapping the coronary ostium.     

Diagnostic Value of 18F-Fluorodeoxyglucose Positron Emission Tomography Computed Tomography in Prosthetic Pulmonary Valve Infective Endocarditis

ObjectivesThe aim of this study was to assess the diagnostic performances of ¹⁸F-fluorodeoxyglucose (¹⁸F-FDG) positron emission tomography (PET)/computed tomography (CT) in congenital heart disease (CHD) patients with pulmonary prosthetic valve or conduit endocarditis (PPVE) suspicion.BackgroundPPVE is a major issue in the growing CHD population. Diagnosis is challenging, and usual imaging tools are not always efficient or validated in this specific population. Particularly, the diagnostic yield of ¹⁸F-FDG PET/CT remains poorly studied in PPVE.MethodsA retrospective multicenter study was conducted in 8 French tertiary centers. Children and adult CHD patients who underwent ¹⁸F-FDG PET/CT in the setting of PPVE suspicion between January 2010 and May 2020 were included. The cases were initially classified as definite, possible, or rejected PPVE regarding the modified Duke criteria and finally by the Endocarditis Team consensus. The result of ¹⁸F-FDG PET/CT had been compared with final diagnosis consensus used as gold-standard in our study.ResultsA total of 66 cases of PPVE suspicion involving 59 patients (median age 23 years, 73% men) were included. Sensitivity, specificity, positive predictive value, and negative predictive value of ¹⁸F-FDG PET/CT in PPVE suspicion were respectively: 79.1% (95% CI: 68.4%-91.4%), 72.7% (95% CI: 60.4%-85.0%), 91.9% (95% CI: 79.6%-100.0%), and 47.1% (95% CI: 34.8%-59.4%). ¹⁸F-FDG PET/CT findings would help to correctly reclassify 57% (4 of 7) of possible PPVE to definite PPVE.ConclusionsUsing ¹⁸F-FDG PET/CT improves the diagnostic accuracy of the Duke criteria in CHD patients with suspected PPVE. Its high positive predictive value could be helpful in routine to shorten diagnosis and treatment delays and improve clinical outcomes.     

Prognostic Value of Radiotracer-Based Perfusion Imaging in Critical Limb Ischemia Patients Undergoing Lower Extremity Revascularization

ObjectivesThe purpose of this study was to evaluate the prognostic value of single-photon emission computed tomography (SPECT)/computed tomography (CT) imaging of angiosome foot perfusion for predicting amputation outcomes in patients with critical limb ischemia (CLI) and diabetes mellitus (DM).BackgroundRadiotracer imaging can assess microvascular foot perfusion and identify regional perfusion abnormalities in patients with critical limb ischemia CLI and DM, but the relationship between perfusion response to revascularization and subsequent clinical outcomes has not been evaluated.MethodsPatients with CLI, DM, and nonhealing foot ulcers (n = 25) were prospectively enrolled for SPECT/CT perfusion imaging of the feet before and after revascularization. CT images were used to segment angiosomes (i.e., 3-dimensional vascular territories) of the foot. Relative changes in radiotracer uptake after revascularization were evaluated within the ulcerated angiosome. Incidence of amputation was assessed at 3 and 12 months after revascularization.ResultsSPECT/CT detected a significantly lower microvascular perfusion response for patients who underwent amputation compared with those who remained amputation free at 3 (p = 0.01) and 12 (p = 0.01) months after revascularization. The cutoff percent change in perfusion for predicting amputation at 3 months was 7.55%, and 11.56% at 12 months. The area under the curve based on the amputation outcome was 0.799 at 3 months and 0.833 at 12 months. The probability of amputation-free survival was significantly higher at 3 (p = 0.002) and 12 months (p = 0.03) for high-perfusion responders than low-perfusion responders to revascularization.ConclusionsSPECT/CT imaging detects regional perfusion responses to lower extremity revascularization and provides prognostic value in patients with CLI (Radiotracer-Based Perfusion Imaging of Patients With Peripheral Arterial Disease; NCT03622359)     

Prognostic Value of Quantitative Metrics From Positron Emission Tomography in Ischemic Heart Failure

ObjectivesThe aim of this study was to investigate the prognostic and clinical value of quantitative positron emission tomographic (PET) metrics in patients with ischemic heart failure.BackgroundAlthough myocardial flow reserve (MFR) is a strong predictor of cardiac risk in patients without heart failure, it is unknown whether quantitative PET metrics improve risk stratification in patients with ischemic heart failure.MethodsThe study included 254 patients referred for stress and rest myocardial perfusion imaging and viability testing using PET. Major adverse cardiac event(s) (MACE) consisted of death, resuscitated sudden cardiac death, heart transplantation, acute coronary syndrome, hospitalization for heart failure, and late revascularization.ResultsMACE occurred in 170 patients (67%) during a median follow-up of 3.3 years. In a multivariate Cox proportional hazards model including multiple quantitative PET metrics, only MFR predicted MACE significantly (p = 0.013). Beyond age, symptom severity, diabetes mellitus, previous myocardial infarction or revascularization, 3-vessel disease, renal insufficiency, ejection fraction, as well as presence and burden of ischemia, scar, and hibernating myocardium, MFR was strongly associated with MACE (adjusted hazard ratio per increase in MFR by 1: 0.63; 95% confidence interval: 0.45 to 0.91). Incorporation of MFR into a risk assessment model incrementally improved the prediction of MACE (likelihood ratio chi-square test [16] = 48.61 vs. chi-square test [15] = 39.20; p = 0.002).ConclusionsIn this retrospective analysis of a single-center cohort, quantitative PET metrics of myocardial blood flow all improved risk stratification in patients with ischemic heart failure. However, in a hypothesis-generating analysis, MFR appears modestly superior to the other metrics as a prognostic index.