Deep Learning of Coronary Calcium Scores From PET/CT Attenuation Maps Accurately Predicts Adverse Cardiovascular Events

BackgroundAssessment of coronary artery calcium (CAC) by computed tomographic (CT) imaging provides an accurate measure of atherosclerotic burden. CAC is also visible in computed tomographic attenuation correction (CTAC) scans, always acquired with cardiac positron emission tomographic (PET) imaging.ObjectivesThe aim of this study was to develop a deep-learning (DL) model capable of fully automated CAC definition from PET CTAC scans.MethodsThe novel DL model, originally developed for video applications, was adapted to rapidly quantify CAC. The model was trained using 9,543 expert-annotated CT scans and was tested in 4,331 patients from an external cohort undergoing PET/CT imaging with major adverse cardiac events (MACEs) (follow-up 4.3 years), including same-day paired electrocardiographically gated CAC scans available in 2,737 patients. MACE risk stratification in 4 CAC score categories (0, 1-100, 101-400, and >400) was analyzed and CAC scores derived from electrocardiographically gated CT scans (standard scores) by expert observers were compared with automatic DL scores from CTAC scans.ResultsAutomatic DL scoring required <6 seconds per scan. DL CTAC scores provided stepwise increase in the risk for MACE across the CAC score categories (HR up to 3.2; P < 0.001). Net reclassification improvement of standard CAC scores over DL CTAC scores was nonsignificant (−0.02; 95% CI: −0.11 to 0.07). The negative predictive values for MACE of zero CAC with standard (85%) and DL CTAC (83%) CAC scores were similar (P = 0.19).ConclusionsDL CTAC scores predict cardiovascular risk similarly to standard CAC scores quantified manually by experienced operators from dedicated electrocardiographically gated CAC scans and can be obtained almost instantly, with no changes to PET/CT scanning protocol.     

A Clinical Tool to Identify Candidates for Stress-First Myocardial Perfusion Imaging

ObjectivesThis study sought to develop a clinical model that identifies a lower-risk population for coronary artery disease that could benefit from stress-first myocardial perfusion imaging (MPI) protocols and that can be used at point of care to risk stratify patients.BackgroundThere is an increasing interest in stress-first and stress-only imaging to reduce patient radiation exposure and improve patient workflow and experience.MethodsA secondary analysis was conducted on a single-center cohort of patients undergoing single-photon emission computed tomography (SPECT) and positron emission tomography (PET) studies. Normal MPI was defined by the absence of perfusion abnormalities and other ischemic markers and the presence of normal left ventricular wall motion and left ventricular ejection fraction. A model was derived using a cohort of 18,389 consecutive patients who underwent SPECT and was validated in a separate cohort of patients who underwent SPECT (n = 5,819), 1 internal cohort of patients who underwent PET (n=4,631), and 1 external PET cohort (n = 7,028).ResultsFinal models were made for men and women and consisted of 9 variables including age, smoking, hypertension, diabetes, dyslipidemia, typical angina, prior percutaneous coronary intervention, prior coronary artery bypass graft, and prior myocardial infarction. Patients with a score ≤1 were stratified as low risk. The model was robust with areas under the curve of 0.684 (95% confidence interval [CI]: 0.674 to 0.694) and 0.681 (95% CI: 0.666 to 0.696) in the derivation cohort, 0.745 (95% CI: 0.728 to 0.762) and 0.701 (95% CI: 0.673 to 0.728) in the SPECT validation cohort, 0.672 (95% CI: 0.649 to 0.696) and 0.686 (95% CI: 0.663 to 0.710) in the internal PET validation cohort, and 0.756 (95% CI: 0.740 to 0.772) and 0.737 (95% CI: 0.716 to 0.757) in the external PET validation cohort in men and women, respectively. Men and women who scored ≤1 had negative likelihood ratios of 0.48 and 0.52, respectively.ConclusionsA novel model, based on easily obtained clinical variables, is proposed to identify patients with low probability of having abnormal MPI results. This point-of-care tool may be used to identify a population that might qualify for stress-first MPI protocols.     

Dynamic Myocardial Perfusion CT for the Detection of Hemodynamically Significant Coronary Artery Disease

ObjectivesIn this international, multicenter study, using third-generation dual-source computed tomography (CT), we investigated the diagnostic performance of dynamic stress CT myocardial perfusion imaging (CT-MPI) in addition to coronary CT angiography (CTA) compared to invasive coronary angiography (ICA) and invasive fractional flow reserve (FFR).BackgroundCT-MPI combined with coronary CTA integrates coronary artery anatomy with inducible myocardial ischemia, showing promising results for the diagnosis of hemodynamically significant coronary artery disease in single-center studies.MethodsAt 9 centers in Europe, Japan, and the United States, 132 patients scheduled for ICA were enrolled; 114 patients successfully completed coronary CTA, adenosine-stress dynamic CT-MPI, and ICA. Invasive FFR was performed in vessels with 25% to 90% stenosis. Data were analyzed by independent core laboratories. For the primary analysis, for each coronary artery the presence of hemodynamically significant obstruction was interpreted by coronary CTA with CT-MPI compared to coronary CTA alone, using an FFR of ≤0.80 and angiographic severity as reference. Territorial absolute myocardial blood flow (MBF) and relative MBF were compared using C-statistics.ResultsICA and FFR identified hemodynamically significant stenoses in 74 of 289 coronary vessels (26%). Coronary CTA with ≥50% stenosis demonstrated a per-vessel sensitivity, specificity, and accuracy for the detection of hemodynamically significant stenosis of 96% (95% CI: 91%-100%), 72% (95% CI: 66%-78%), and 78% (95% CI: 73%-83%), respectively. Coronary CTA with CT-MPI showed a lower sensitivity (84%; 95% CI: 75%-92%) but higher specificity (89%; 95% CI: 85%-93%) and accuracy (88%; 95% CI: 84%-92%). The areas under the receiver-operating characteristic curve of absolute MBF and relative MBF were 0.79 (95% CI: 0.71-0.86) and 0.82 (95% CI: 0.74-0.88), respectively. The median dose-length product of CT-MPI and coronary CTA were 313 mGy·cm and 138 mGy·cm, respectively.ConclusionsDynamic CT-MPI offers incremental diagnostic value over coronary CTA alone for the identification of hemodynamically significant coronary artery disease. Generalized results from this multicenter study encourage broader consideration of dynamic CT-MPI in clinical practice. (Dynamic Stress Perfusion CT for Detection of Inducible Myocardial Ischemia [SPECIFIC]; NCT02810795)     

Prognostic Value of RCA Pericoronary Adipose Tissue CT-Attenuation Beyond High-Risk Plaques,Plaque Volume,and Ischemia

ObjectivesThis study was designed to assess the prognostic value of pericoronary adipose tissue computed tomography attenuation (PCATa) beyond quantitative coronary computed tomography angiography (CCTA)–derived plaque volume and positron emission tomography (PET) determined ischemia.BackgroundInflammation plays a crucial role in atherosclerosis. PCATa has been shown to assess coronary-specific inflammation and is of prognostic value in patients with suspected coronary artery disease (CAD).MethodsA total of 539 patients who underwent CCTA and [¹⁵O]H₂O PET perfusion imaging because of suspected CAD were included. Imaging assessment included coronary artery calcium score (CACS), presence of obstructive CAD (≥50% stenosis) and high-risk plaques (HRPs), total plaque volume (TPV), calcified/noncalcified plaque volume (CPV/NCPV), PCATa, and myocardial ischemia. The endpoint was a composite of death and nonfatal myocardial infarction. Prognostic thresholds were determined for quantitative CCTA variables.ResultsDuring a median follow-up of 5.0 (interquartile range: 4.7 to 5.0) years, 33 events occurred. CACS >59 Agatston units, obstructive CAD, HRPs, TPV >220 mm³, CPV >110 mm³, NCPV >85 mm³, and myocardial ischemia were associated with shorter time to the endpoint with unadjusted hazard ratios (HRs) of 4.17 (95% confidence interval [CI]: 1.80 to 9.64), 4.88 (95% CI: 1.88 to 12.65), 3.41 (95% CI: 1.72 to 6.75), 7.91 (95% CI: 3.05 to 20.49), 5.82 (95% CI: 2.40 to 14.10), 8.07 (95% CI: 3.33 to 19.55), and 4.25 (95% CI: 1.84 to 9.78), respectively (p < 0.05 for all). Right coronary artery (RCA) PCATa above scanner specific thresholds was associated with worse prognosis (unadjusted HR: 2.84; 95% CI: 1.44 to 5.63; p = 0.003), whereas left anterior descending artery and circumflex artery PCATa were not related to outcome. RCA PCATa above scanner specific thresholds retained is prognostic value adjusted for imaging variables and clinical characteristics associated with the endpoint (adjusted HR: 2.45; 95% CI: 1.23 to 4.93; p = 0.011).ConclusionsParameters associated with atherosclerotic burden and ischemia were more strongly associated with outcome than RCA PCATa. Nonetheless, RCA PCATa was of prognostic value beyond clinical characteristics, CACS, obstructive CAD, HRPs, TPV, CPV, NCPV, and ischemia.     

Comparison Between ESC and Duke Criteria for the Diagnosis of Prosthetic Valve Infective Endocarditis

ObjectivesThe primary objective was to assess the value of the European Society of Cardiology (ESC) criteria, including ¹⁸F-fluorodeoxyglucose positron emission tomography/computed tomography (¹⁸F-FDG-PET/CT) in prosthetic valve infective endocarditis (PVE). Secondary objectives were: 1) to assess the reproducibility of ¹⁸F-FDG-PET/CT; 2) to compare its diagnostic value with that of echocardiography; and 3) to assess the diagnostic value of the presence of a diffuse splenic uptakeBackground¹⁸F-FDG PET/CT has been added as a major criterion in the ESC 2015 infective endocarditis (IE) guidelines, but the benefit of the ESC criteria has not been prospectively compared with the conventional Duke criteria.MethodsBetween 2014 and 2017, 175 patients with suspected PVE were prospectively included in 3 French centers. After exclusion of patients with uninterpretable ¹⁸F-FDG PET/CT, 115 patients were evaluated, including 91 definite and 24 rejected IE, as defined by an expert consensus.ResultsCardiac uptake by ¹⁸F-FDG PET/CT was observed in 67 of 91 patients with definite PVE and 6 with rejected IE (sensitivity 73.6% [95% confidence interval (CI): 63.3% to 82.3%], specificity 75% [95% CI: 53.3% to 90.2%]). The ESC 2015 classification increased the sensitivity of Duke criteria from 57.1% (95% CI: 46.3% to 67.5%) to 83.5% (95% CI: 74.3% to 90.5%) (p < 0.001), but decreased its specificity from 95.8% (95% CI: 78.9% to 99.9%) to 70.8% (95% CI: 48.9% to 87.4%). Intraobserver reproducibility of ¹⁸F-FDG PET/CT was good (kappa = 0.84) but interobserver reproducibility was less satisfactory (kappa = 0.63). A diffuse splenic uptake was observed in 24 (20.3%) patients, including 23 (25.3%) of definite PVE, and only 1 (4.2%) rejected PVE (p = 0.024).Conclusions¹⁸F-FDG PET/CT is a useful diagnostic tool in suspected PVE, and explains the greater sensitivity of ESC criteria than Duke criteria. However, ¹⁸F-FDG PET/CT also presents with important limitations concerning its feasibility, specificity, and reproducibility. Our study describes for the first time a new endocarditis criterion, that is, the presence of a diffuse splenic uptake on ¹⁸F-FDG PET/CT.     

Fractal Analysis of Dynamic Stress CT-Perfusion Imaging for Detection of Hemodynamically Relevant Coronary Artery Disease

BackgroundCombined computed tomography–derived myocardial blood flow (CTP-MBF) and computed tomography angiography (CTA) has shown good diagnostic performance for detection of coronary artery disease (CAD). However, fractal analysis might provide additional insight into ischemia pathophysiology by characterizing multiscale perfusion patterns and, therefore, may be useful in diagnosing hemodynamically significant CAD.ObjectivesThe purpose of this study was to investigate, in a multicenter setting, whether fractal analysis of perfusion improves detection of hemodynamically relevant CAD over myocardial blood flow quantification (CTP-MBF) using dynamic, 4-dimensional, dynamic stress myocardial computed tomography perfusion (CTP) imaging.MethodsIn total, 7 centers participating in the prospective AMPLIFiED (Assessment of Myocardial Perfusion Linked to Infarction and Fibrosis Explored with Dual-source CT) study acquired CTP and CTA data in patients with suspected or known CAD. Hemodynamically relevant CAD was defined as ≥90% stenosis on invasive coronary angiography or fractional flow reserve <0.80. Both fractal analysis and CTP-MBF quantification were performed on CTP images and were combined with CTA results.ResultsThis study population included 127 participants, among them 61 patients, or 79 vessels, with CAD as per invasive reference standard. Compared with the combination of CTP-MBF and CTA, combined fractal analysis and CTA improved sensitivity on the per-patient level from 84% (95% CI: 72%-92%) to 95% (95% CI: 86%-99%; P = 0.01) and specificity from 70% (95% CI: 57%-82%) to 89% (95% CI: 78%-96%; P = 0.02). The area under the receiver-operating characteristic curve improved from 0.83 (95% CI: 0.75-0.90) to 0.92 (95% CI: 0.86-0.98; P = 0.01).ConclusionsFractal analysis constitutes a quantitative and pathophysiologically meaningful approach to myocardial perfusion analysis using dynamic stress CTP, which improved diagnostic performance over CTP-MBF when combined with anatomical information from CTA.     

Diagnostic Accuracy of Cardiovascular Magnetic Resonance for Cardiac Transplant Rejection: A Meta-Analysis

ObjectivesThe aim of this meta-analysis was to assess the diagnostic performance of various CMR imaging parameters for evaluating acute cardiac transplant rejection.BackgroundEndomyocardial biopsy is the current gold standard for detection of acute cardiac transplant rejection. Cardiac magnetic resonance (CMR) is uniquely capable of myocardial tissue characterization and may be useful as a noninvasive alternative for the diagnosis of graft rejection.MethodsPubMed and Web of Science were searched for relevant publications reporting on the use of CMR myocardial tissue characterization for detection of acute cardiac transplant rejection with endomyocardial biopsy as the reference standard. Pooled sensitivity, specificity, and hierarchical modeling–based summary receiver-operating characteristic curves were calculated.ResultsOf 478 papers, 10 studies comprising 564 patients were included. The sensitivity and specificity for the detection of acute cardiac transplant rejection were 84.6 (95% CI: 65.6-94.0) and 70.1 (95% CI: 54.2-82.2) for T1, 86.5 (95% CI: 72.1-94.1) and 85.9 (95% CI: 65.2-94.6) for T2, 91.3 (95% CI: 63.9-98.4) and 67.6 (95% CI: 56.1-77.4) for extracellular volume fraction (ECV), and 50.1 (95% CI: 31.2-68.9) and 60.2 (95% CI: 36.7-79.7) for late gadolinium enhancement (LGE). The areas under the hierarchical modeling–based summary receiver-operating characteristic curve were 0.84 (95% CI: 0.81-0.87) for T1, 0.92 (95% CI: 0.89-94) for T2, 0.78 (95% CI: 0.74-0.81) for ECV, and 0.56 (95% CI: 0.51-0.60) for LGE. T2 values demonstrated the highest diagnostic accuracy, followed by native T1, ECV, and LGE (all P values <0.001 for T1, ECV, and LGE vs T2).ConclusionsT2 mapping demonstrated higher diagnostic accuracy than other CMR techniques. Native T1 and ECV provide high diagnostic use but lower diagnostic accuracy compared with T2, which was related primarily to lower specificity. LGE showed poor diagnostic performance for detection of rejection.     

Downstream Cascades of Care Following High-Sensitivity Troponin Test Implementation

BackgroundPatients with chest pain are often evaluated for acute myocardial infarction through troponin testing, which may prompt downstream services (cascades) of uncertain value.ObjectivesThis study sought to determine the association of high-sensitivity cardiac troponin (hs-cTn) assay implementation with cascade events.MethodsUsing electronic health record and billing data, this study examined patient-visits to 5 emergency departments from April 1, 2017, to April 1, 2019. Difference-in-differences analysis compared patient-visits for chest pain (n = 7,564) to patient-visits for other symptoms (n = 100,415) (irrespective of troponin testing) before and after hs-cTn assay implementation. Outcomes included presence of any cascade event potentially associated with an initial hs-cTn test (primary), individual cascade events, length of stay, and spending on cardiac services.ResultsFollowing hs-cTn implementation, patients with chest pain had a 2.8% (95% confidence interval [CI]: 0.72% to 4.9%) net increase in experiencing any cascade event. They were more likely to have multiple troponin tests (10.5%; 95% CI: 9.0% to 12.0%) and electrocardiograms (7.1 per 100 patient-visits; 95% CI: 1.8 to 12.4). However, they received net fewer computed tomography scans (?1.5 per 100 patient-visits; 95% CI: ?1.8 to ?1.1), stress tests (?5.9 per 100 patient-visits; 95% CI: ?6.5 to ?5.3), and percutaneous coronary intervention (PCI) (?0.65 per 100 patient-visits; 95% CI: ?1.01 to ?0.30) and were less likely to receive cardiac medications, undergo cardiology evaluation (?3.5%; 95% CI: ?4.5% to 2.6%), or be hospitalized (?5.8%; 95% CI: ?7.7% to ?3.8%). Patients with chest pain had lower net mean length of stay (?0.24 days; 95% CI: ?0.32 to ?0.16) but no net change in spending.ConclusionsHs-cTn assay implementation was associated with more net upfront tests yet fewer net stress tests, PCI, cardiology evaluations, and hospital admissions in patients with chest pain relative to patients with other symptoms.     

Diagnostic Accuracy of [11C]PIB Positron Emission Tomography for Detection of Cardiac Amyloidosis

ObjectivesThis dual-site study evaluated the diagnostic accuracy of the method.BackgroundPittsburgh compound ([¹¹C]PIB) positron emission tomography (PIB-PET) has shown promise as a specific and noninvasive method for the diagnosis of cardiac amyloidosis (CA).MethodsThe study had 2 parts. In the initial study, 51 subjects were included, 36 patients with known CA and increased wall thickness (15 immunoglobulin light chain [AL] and 21 transthyretin [ATTR] amyloidosis) and 15 control patients (7 were nonamyloid hypertrophic and 8 healthy volunteers). Subjects underwent PIB-PET and echocardiography. Sensitivity and specificity of PIB-PET were established for 2 simple semiquantitative approaches, standardized uptake value ratio (SUVR) and retention index (RI). The second part of the study included 11 amyloidosis patients (5 AL and 6 hereditary ATTR) without increased wall thickness to which the optimal cutoff values of SUVR (>1.09) and RI (>0.037 min^-1) were applied prospectively.ResultsThe diagnostic accuracy of visual inspection of [¹¹C]PIB uptake was 100% in discriminating CA patients with increased wall thickness from controls. Semiquantitative [¹¹C]PIB uptake discriminated CA from controls with a 94% (95% confidence interval [CI]: 80% to 99%) sensitivity for both SUVR and RI and specificity of 93% (95% CI: 66% to 100%) for SUVR and 100% (95% CI: 75% to 100%) for RI. [¹¹C]PIB uptake was significantly higher in AL-CA than in ATTR-CA patients (p < 0.001) and discriminated AL-CA from controls with 100% (95% CI: 88% to 100%) accuracy for both the semiquantitative measures. In the prospective group without increased wall thickness, RI was elevated compared to controls (p = 0.001) and 5 of 11 subjects were evaluated as [¹¹C]PIB PET positive.ConclusionsIn a dual-center setting, [¹¹C]PIB PET was highly accurate in detecting cardiac involvement in the main amyloid subtypes, with 100% accuracy in AL amyloidosis. A proportion of amyloidosis patients without known cardiac involvement were [¹¹C]PIB PET positive, indicating that the method may detect early stages of CA.     

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.     

Coronary CT Angiography in Patients With Non-ST-Segment Elevation Acute Coronary Syndrome

BackgroundIn patients with non–ST-segment elevation acute coronary syndrome (NSTEACS), coronary pathology may range from structurally normal vessels to severe coronary artery disease.ObjectivesThe purpose of this study was to test if coronary computed tomography angiography (CTA) may be used to exclude coronary artery stenosis ≥50% in patients with NSTEACS.MethodsThe VERDICT (Very Early Versus Deferred Invasive Evaluation Using Computerized Tomography in Patients With Acute Coronary Syndromes) trial (NCT02061891) evaluated the outcome of patients with confirmed NSTEACS randomized 1:1 to very early (within 12 h) or standard (48 to 72 h) invasive coronary angiography (ICA). As an observational component of the trial, a clinically blinded coronary CTA was conducted prior to ICA in both groups. The primary endpoint was the ability of coronary CTA to rule out coronary artery stenosis (≥50% stenosis) in the entire population, expressed as the negative predictive value (NPV), using ICA as the reference standard.ResultsCoronary CTA was conducted in 1,023 patients—very early, 2.5 h (interquartile range [IQR]: 1.8 to 4.2 h), n = 583; and standard, 59.9 h (IQR: 38.9 to 86.7 h); n = 440 after the diagnosis of NSTEACS was made. A coronary stenosis ≥50% was found by coronary CTA in 68.9% and by ICA in 67.4% of the patients. Per-patient NPV of coronary CTA was 90.9% (95% confidence interval [CI]: 86.8% to 94.1%) and the positive predictive value, sensitivity, and specificity were 87.9% (95% CI: 85.3% to 90.1%), 96.5% (95% CI: 94.9% to 97.8%) and 72.4% (95% CI: 67.2% to 77.1%), respectively. NPV was not influenced by patient characteristics or clinical risk profile and was similar in the very early and the standard strategy group.ConclusionsCoronary CTA has a high diagnostic accuracy to rule out clinically significant coronary artery disease in patients with NSTEACS.     

Incidence and Predictors of Atrial Fibrillation in Cardiac Sarcoidosis: A Multimodality Imaging Study

BackgroundIn cardiac sarcoidosis (CS), the risk and predictors of new-onset atrial fibrillation (AF) are poorly known.ObjectivesThe authors evaluated the incidence and characteristics of AF in newly diagnosed CS.MethodsThe authors studied 118 patients (78 women, mean age 50 years) with AF-naive CS having undergone cardiac ¹⁸F-fluorodexoyglucose positron emission tomography (¹⁸F-FDG PET) at the time of diagnosis. Details of patient characteristics and medical or device therapy were collected from hospital charts. The PET scans were re-analyzed for presence of atrial and ventricular inflammation, and coincident cardiac magnetic resonance (CMR) studies and single-photon emission computed tomography (SPECT) perfusions were analyzed for cardiac structure and function, including the presence and extent of myocardial scarring. Detection of AF was based on interrogation of intracardiac devices and on ambulatory or 12-lead electrocardiograms.ResultsAltogether 34 patients (29%) suffered paroxysms of AF during follow-up (median, 3 years) with persistent AF developing in 7 patients and permanent AF in 4. The estimated 5-year incidence of AF was 55% (95% CI: 34%-72%) in the 39 patients with atrial ¹⁸F-FDG uptake at the time of diagnosis vs 18% (95% CI: 10%-28%) in the 79 patients without atrial uptake (P < 0.001). In cause-specific Cox regression analysis, atrial uptake was an independent predictor of AF (P < 0.001) with HR of 6.01 (95% CI: 2.64-13.66). Other independent predictors were an increased left atrial maximum volume (P < 0.01) and history of sleep apnea (P < 0.01). Ventricular involvement by PET, SPECT, or CMR was nonpredictive. Symptoms of AF prompted electrical cardioversion in 12 patients (35%). Three of the 34 patients (9%) experiencing AF suffered a stroke versus none of those remaining free of AF.ConclusionsIn newly diagnosed CS, future AF is relatively common and associated with atrial inflammation and enlargement on multimodality cardiac imaging.     

Second-Line Myocardial Perfusion Imaging to Detect Obstructive Stenosis: Head-to-Head Comparison of CMR and PET

BackgroundGuidelines recommend verification of myocardial ischemia by selective second-line myocardial perfusion imaging (MPI) following a coronary computed tomography angiography (CTA) with suspected obstructive coronary artery disease (CAD). Head-to-head data on the diagnostic performance of different MPI modalities in this setting are sparse.ObjectivesThe authors sought to compare, head-to-head, the diagnostic performance of selective MPI by 3.0-T cardiac magnetic resonance (CMR) and ⁸²rubidium positron emission tomography (RbPET) in patients with suspected obstructive stenosis at coronary CTA using invasive coronary angiography (ICA) with fractional flow reserve (FFR) as reference.MethodsConsecutive patients (n = 1,732, mean age: 59.1 ± 9.5 years, 57.2% men) referred for coronary CTA with symptoms suggestive of obstructive CAD were included. Patients with suspected stenosis were referred for both CMR and RbPET and subsequently ICA. Obstructive CAD was defined as FFR ≤0.80 or >90% diameter stenosis by visual assessment.ResultsIn total, 445 patients had suspected stenosis on coronary CTA. Of these, 372 patients completed both CMR, RbPET and subsequent ICA with FFR. Hemodynamically obstructive CAD was identified in 164 of 372 (44.1%) patients. Sensitivities for CMR and RbPET were 59% (95% CI: 51%-67%) and 64% (95% CI: 56%-71%); P = 0.21, respectively, and specificities 84% (95% CI: 78%-89%) and 89% (95% CI: 84%-93%]); P = 0.08, respectively. Overall accuracy was higher for RbPET compared with CMR (73% vs 78%; P = 0.03).ConclusionsIn patients with suspected obstructive stenosis at coronary CTA, CMR, and RbPET show similar and moderate sensitivities but high specificities compared with ICA with FFR. This patient group represents a diagnostic challenge with frequent mismatch between advanced MPI tests and invasive measurements. (Danish Study of Non-Invasive Diagnostic Testing in Coronary Artery Disease 2 [Dan-NICAD 2]; NCT03481712)     

Transcatheter Self-Expandable Valve Implantation for Aortic Stenosis in Small Aortic Annuli: The TAVI-SMALL Registry

ObjectivesThe aim of this study was to evaluate and compare the outcomes of transcatheter self-expandable prostheses in patients with small annuli.BackgroundTranscatheter aortic heart valves appear to have better performance than surgical valves in terms of prosthesis-patient mismatch, especially in patients with aortic stenosis with small aortic annuli.MethodsTAVI-SMALL (International Multicenter Registry to Evaluate the Performance of Self-Expandable Valves in Small Aortic Annuli) is a retrospective registry of patients with severe aortic stenosis and small annuli (annular perimeter <72 mm or area <400 mm² on computed tomography) treated with transcatheter self-expandable valves (n = 859; Evolut R, n = 397; Evolut PRO, n = 84; ACURATE, n = 201; Portico, n = 177). Primary endpoints were post-procedural mean aortic gradient, indexed effective orifice area, and rate of severe prosthesis-patient mismatch.ResultsPre-discharge gradients were consistently low in every group, with a slight benefit with the Evolut R (8.1 mm Hg; 95% confidence interval [CI]: 7.7 to 8.5 mm Hg) and Evolut PRO (6.9 mm Hg; 95% CI: 6.3 to 7.6 mm Hg) compared with the ACURATE (9.6 mm Hg; 95% CI: 8.9 to 10.2 mm Hg) and Portico (8.9 mm Hg; 95% CI: 8.2 to 9.6 mm Hg) groups (p < 0.001). Mean indexed effective orifice area was 1.04 cm²/m² (95% CI: 1.01 to 1.08 cm²/m²) with a trend toward lower values with the Portico. No significant differences were reported in terms of severe prosthesis-patient mismatch (overall rate 9.4%; p = 0.134), permanent pacemaker implantation (15.6%), and periprocedural and 1-year adverse events. Pre-discharge more than mild paravalvular leaks were significantly more common with the Portico (19.2%) and less common with the Evolut PRO (3.6%) compared with the Evolut R (11.8%) and ACURATE (9%) groups.ConclusionsTranscatheter self-expandable valves showed optimal clinical and echocardiographic results in patients with small aortic annuli, although supra-annular functioning transcatheter heart valves seemed to slightly outperform intra-annular functioning ones. The role of transcatheter aortic valve replacement with self-expandable valves for the treatment of aortic stenosis in patients with small annuli needs to be confirmed in larger trials.     

Subphenotyping of Patients With Aortic Stenosis by Unsupervised Agglomerative Clustering of Echocardiographic and Hemodynamic Data

ObjectivesThe aim of this retrospective analysis was to categorize patients with severe aortic stenosis (AS) according to clinical presentation by applying unsupervised machine learning.BackgroundPatients with severe AS present with heterogeneous clinical phenotypes, depending on disease progression and comorbidities.MethodsUnsupervised agglomerative clustering was applied to preprocedural data from echocardiography and right heart catheterization from 366 consecutively enrolled patients undergoing transcatheter aortic valve replacement for severe AS.ResultsCluster analysis revealed 4 distinct phenotypes. Patients in cluster 1 (n = 164 [44.8%]), serving as a reference, presented with regular cardiac function and without pulmonary hypertension (PH). Accordingly, estimated 2-year survival was 90.6% (95% CI: 85.8%-95.6%). Clusters 2 (n = 66 [18.0%]) and 4 (n = 91 [24.9%]) both comprised patients with postcapillary PH. Yet patients in cluster 2 with preserved left and right ventricular structure and function showed a similar survival as those in cluster 1 (2-year survival 85.8%; 95% CI: 76.9%-95.6%), whereas patients in cluster 4 with dilatation of all heart chambers and a high prevalence of mitral and tricuspid regurgitation (12.5% and 14.8%, respectively) died more often (2-year survival 74.9% [95% CI: 65.9%-85.2%]; HR for 2-year mortality: 2.8 [95% CI: 1.4-5.5]). Patients in cluster 3, the smallest (n = 45 [12.3%]), displayed the most extensive disease characteristics (ie, left and right heart dysfunction together with combined pre- and postcapillary PH), and 2-year survival was accordingly reduced (77.3% [95% CI: 65.2%-91.6%]; HR for 2-year mortality: 2.6 [95% CI: 1.1-6.2]).ConclusionsUnsupervised machine learning aids in capturing complex clinical presentations as observed in patients with severe AS. Importantly, structural alterations in left and right heart morphology, possibly due to genetic predisposition, constitute an equally sensitive indicator of poor prognosis compared with high-grade PH.     

Effect of Immunosuppressive Therapy and Biopsy Status in Monitoring Therapy Response in Suspected Cardiac Sarcoidosis

BackgroundPatients with suspected cardiac sarcoidosis frequently undergo fluorodeoxyglucose (FDG)–positron emission tomography (PET)/computed tomography (CT) imaging to assess disease activity at baseline and after treatment initiation.ObjectivesThis study investigated the effect of immunosuppressive therapy and biopsy status to achieve complete treatment response (CTR), partial treatment response (PTR), or no response (NR) on myocardial FDG-PET/CT.MethodsThis study analyzed 83 patients with suspected cardiac sarcoidosis (aged 53 ± 1.8 years, 71% were male, 69% were White, 61% had a history of biopsy-confirmed sarcoidosis) who were treatment naive, had evidence of myocardial FDG at baseline, and underwent repeat PET imaging after treatment initiation. CTR was graded visually, and PTR/NR were measured both visually and quantitatively using the total glycolytic activity. Patients were also evaluated for the occurrence of death, sustained ventricular arrhythmias, and heart failure admissions.ResultsOverall, 59 patients (71%) achieved CTR/PTR (30%/41%) at follow-up scan (P = 0.04). Total glycolytic activity and visual estimate of PTR/NR had excellent agreement (κ = 0.86 [95% CI: 0.72-0.99]; P < 0.0001). In patients receiving prednisone only, the highest rates of CTR/PTR were observed in patients initiated on moderate or high dose (P < 0.01). In a regression model, moderate prednisone start dose (P = 0.03) was more strongly associated with achieving CTR/PTR than was high prednisone start dose. However, the latter patients were tapered faster between start dose and follow-up scan (P < 0.01). After a median follow-up of 4.7 (IQR: 3.1-7.8) years, patients who were biopsy-proven (vs non-biopsy-proven; P = 0.029) and with preserved left ventricular function (P = 002) were less likely to experience major adverse cardiac events. Outcomes based on treatment response status (CTR vs PTR vs NR; P = 0.23) were not significantly different.ConclusionsAmong patients with suspected sarcoidosis and evidence of myocardial inflammation, treatment response by serial FDG-PET was variable, but a favorable response was more common when using moderate-to-high intensity prednisone dose. Biopsy-proven individuals and those with preserved systolic function were less likely to experience adverse outcomes during follow-up.     

Early Diagnosis of Myocardial Infarction With Point-of-Care High-Sensitivity Cardiac Troponin I

BackgroundUntil now, high-sensitivity cardiac troponin (hs-cTn) assays were mainly developed for large central laboratory platforms.ObjectivesThis study aimed to assess the clinical performance of a point-of-care (POC)-hs-cTnI assay in patients with suspected myocardial infarction (MI).MethodsThis study enrolled patients presenting to the emergency department with symptoms suggestive of MI. Two cardiologists centrally adjudicated the final diagnosis using all clinical data including cardiac imaging. The primary objective was to directly compare diagnostic accuracy of POC-hs-cTnI-TriageTrue versus best-validated central laboratory assays. Secondary objectives included the derivation and validation of a POC-hs-cTnI-TriageTrue–specific 0/1-h algorithm.ResultsMI was the adjudicated final diagnosis in 178 of 1,261 patients (14%). The area under the curve (AUC) for POC-hs-cTnI-TriageTrue at presentation was 0.95 (95% confidence interval [CI]: 0.93 to 0.96) and was at least comparable to hs-cTnT-Elecsys (AUC: 0.94; 95% CI: 0.93 to 0.96; p = 0.213) and hs-cTnI-Architect (AUC: 0.92; 95% CI: 0.90 to 0.93; p < 0.001). A single cutoff concentration <3 ng/l at presentation identified 45% of patients at low risk with a negative predictive value (NPV) of 100% (95% CI: 99.4% to 100%). A single cutoff concentration >60 ng/l identified patients at high risk with a positive predictive value (PPV) of 76.8% (95% CI: 68.9% to 83.6%). The 0/1-h algorithm ruled out 55% of patients (NPV: 100%; 95% CI: 98.8% to 100%), and ruled in 18% of patients (PPV: 76.8%; 95% CI: 67.2% to 84.7%). Ruled-out patients had cumulative event rates of 0% at 30 days and 1.6% at 2 years. This study confirmed these findings in a secondary analysis including hs-cTnI-Architect for central adjudication.ConclusionsThe POC-hs-cTnI-TriageTrue assay provides high diagnostic accuracy in patients with suspected MI with a clinical performance that is at least comparable to that of best-validated central laboratory assays. (Advantageous Predictors of Acute Coronary Syndromes Evaluation Study [APACE]; NCT00470587)     

Native T1 Mapping,Extracellular Volume Mapping,and Late Gadolinium Enhancement in Cardiac Amyloidosis: A Meta-Analysis

ObjectivesThis study aimed to compare the diagnostic and prognostic performance of native T1 mapping (T1), extracellular volume (ECV) mapping, and late gadolinium enhancement (LGE) imaging for evaluating cardiac amyloidosis (CA).BackgroundCA is a progressive infiltrative process in the extracellular space that is often underdiagnosed and holds a poor prognosis. Cardiac magnetic resonance (CMR) offers novel techniques for detecting and quantifying the disease burden of CA.MethodsWe searched PubMed for published studies using native T1, ECV, or LGE to diagnose and prognosticate CA. A total of 18 diagnostic (n = 2,015) and 13 prognostic studies (n = 1,483) were included for analysis. Pooled sensitivities, specificities, diagnostic odds ratios (DORs) of all diagnostic tests were assessed by bivariate analysis. Pooled hazard ratios (HRs) for mortality for the 3 techniques were determined.ResultsBivariate comparison showed that ECV (DOR: 84.6; 95% confidence interval [CI]: 30.3 to 236.2) had a significantly higher DOR for CA than LGE (DOR: 20.1; 95% CI: 9.1 to 44.1; p = 0.03 vs. ECV). There was no significant difference between LGE and native T1 for sensitivity, specificity, and DOR. HR was significantly higher for ECV (HR: 4.27; 95% CI: 2.87 to 6.37) compared with LGE (HR: 2.60; 95% CI: 1.90 to 3.56; p = 0.03 vs. ECV) and native T1 (HR: 2.04; 95% CI: 1.24 to 3.37; p = 0.01 vs. ECV).ConclusionsECV demonstrates a higher diagnostic OR for assessing cardiac amyloid than LGE and a higher HR for adverse events compared with LGE and native T1. In addition, native T1 showed similar sensitivity and specificity as ECV and LGE without requiring contrast material. Although limited by study heterogeneity, this meta-analysis suggests that ECV provides high diagnostic and prognostic utility for the assessment of cardiac amyloidosis.     

Incidence,Predictors, and Outcomes of Endocarditis After Transcatheter Aortic Valve Replacement in the United States

ObjectivesThis study sought to evaluate the incidence and outcomes of endocarditis after transcatheter aortic valve replacement (TAVR).BackgroundData about endocarditis after TAVR are limited.MethodsThe study investigated Medicare patients who underwent TAVR from 2012 to 2017 and identified patients admitted with endocarditis during follow-up using a validated algorithm. The main study outcome was all-cause mortality.ResultsOf 134,717 patients who underwent TAVR, 1868 patients developed endocarditis during follow-up (incidence 0.87%/year), with majority of infections (65.0%) occurring within 1 year. Incidence of endocarditis declined in recent years. The most common organisms were Staphylococcus (22.0%), Streptococcus (20.0%), and Enterococcus (15.5%). Important predictors for endocarditis were younger age at TAVR, male sex, prior endocarditis, end-stage renal disease, repeat TAVR procedures, liver and lung disease, and post-TAVR acute kidney injury. Thirty-day and 1-year mortality were 18.5% and 45.6%, respectively. After adjusting for comorbidities and procedural complications, endocarditis after TAVR was associated with 3-fold higher risk of mortality (44.9 vs. 16.2 deaths per 100 person-years; adjusted hazard ratio [aHR]: 2.94; 95% confidence interval [CI]: 2.77 to 3.12; p < 0.0001). End-stage renal disease (aHR: 2.12; 95% CI: 1.72 to 2.60), endocarditis complicated by cardiogenic shock (aHR: 2.50, 95% CI: 1.56 to 4.02), ischemic stroke (aHR: 1.56; 95% CI: 1.07 to 2.28), intracerebral hemorrhage (aHR: 1.67; 95% CI: 1.01 to 2.76), acute kidney injury (aHR: 1.44; 95% CI: 1.27 to 1.63), blood transfusion (aHR: 1.28; 95% CI: 1.09 to 1.50), staphylococcal (aHR: 1.71; 95% CI: 1.49 to 1.97), and fungal endocarditis (aHR: 1.72; 95% CI: 1.23 to 2.39) (p < 0.05 for all) portended higher mortality following endocarditis.ConclusionsThe incidence of endocarditis after TAVR is low and declining. However, it is associated with poor prognosis with one-half the patients dying within 1 year.     

Age-Related Outcomes After Transcatheter Aortic Valve Replacement: Insights From the SwissTAVI Registry

ObjectivesThe aim of this study was to investigate age-related outcomes of patients undergoing transcatheter aortic valve replacement (TAVR) as assessed in a nationwide, prospective, multicenter cohort study.BackgroundTAVR is the preferred treatment for elderly patients with severe aortic stenosis and is expanding into lower age groups.MethodsData from the SwissTAVI Registry were analyzed. Clinical outcomes were compared between patients 70 years of age or younger (n = 324), 70 to 79 years of age (n = 1,913), 80 to 89 years of age (n = 4,353), and older than 90 years of age (n = 507). Observed deaths were correlated with expected deaths in the general Swiss population using standardized mortality ratios.ResultsBetween February 2011 and June 2018, 7,097 patients (mean age 82.0 ± 6.4 years, 49.6% women) underwent TAVR at 15 hospitals in Switzerland. Procedural characteristics were similar; however, older patients more often had discharge to the referring hospital or a rehabilitation facility after TAVR. Using adjusted analyses, a linear trend for mortality (30-day adjusted hazard ratio [HR_adj]: 1.45; 95% confidence interval [CI]: 1.18 to 1.77; 1-year HR_adj: 1.12; 95% CI: 1.01 to 1.24), cerebrovascular accidents (30-day HR_adj: 1.35; 95% CI: 1.09 to 1.66; 1-year HR_adj: 1.21; 95% CI: 1.02 to 1.45), and pacemaker implantation (30-day HR_adj: 1.23; 95% CI: 1.12 to 1.34; 1-year HR_adj: 1.19; 95% CI: 1.09 to 1.30) was observed with increasing age. Furthermore, standardized mortality ratios were 12.63 (95% CI: 9.06 to 17.58), 4.09 (95% CI: 3.56 to 4.74), 1.63 (95% CI: 1.50 to 1.78), and 0.93 (95% CI: 0.76 to 1.14) for TAVR patients in relation to the Swiss population <70, 70 to 79, 80 to 89 and ≥90 years of age, respectively.ConclusionsIncreasing age is associated with a linear trend for mortality, stroke, and pacemaker implantation during early and longer-term follow-up after TAVR. Standardized mortality ratios were higher for TAVR patients younger than 90 years of age compared with expected rates of mortality in an age- and sex-matched Swiss population. (SWISS TAVI Registry; NCT01368250)