Early versus late acute coronary syndrome risk patterns of coronary atherosclerotic plaque

AIMS

The temporal instability of coronary atherosclerotic plaque preceding an incident acute coronary syndrome (ACS) is not well defined. We sought to examine differences in the volume and composition of coronary atherosclerosis between patients experiencing an early (≤90 days) versus late ACS (>90 days) after baseline coronary computed tomography angiography (CCTA).

METHODS AND RESULTS

From a multicenter study, we enrolled patients who underwent a clinically indicated baseline CCTA and experienced ACS during follow-up. Separate core laboratories performed blinded adjudication of ACS events and quantification of CCTA including compositional plaque volumes by Hounsfield units (HU): calcified plaque >350 HU, fibrous plaque 131-350 HU, fibrofatty plaque 31-130 HU and necrotic core <30 HU. In 234 patients (mean age 62 ± 12 years, 36% women), early and late ACS occurred in 129 and 105 patients after a mean of 395 ± 622 days, respectively. Patients with early ACS had a greater maximal diameter stenosis and maximal cross-sectional plaque burden as compared to patients with late ACS (P < 0.05). Larger total, fibrous, fibrofatty, and necrotic core volumes were observed in the early ACS group (P < 0.05). Findings for total, fibrous, fibrofatty, and necrotic core volumes were reproduced in an external validation cohort (P < 0.05).

CONCLUSIONS

Volumetric differences in composition of coronary atherosclerosis exist between ACS patients according to their timing antecedent to the acute event. These data support that a large burden of non-calcified plaque on CCTA is strongly associated with near-term plaque instability and ACS risk.

Prognostic Interplay Between Coronary Artery Calcium Scoring and Cardiorespiratory FItness: The CAC-FIT Study

OBJECTIVE

To assess the incremental prognostic role of coronary artery calcium score (CACS) and exercise capacity (EC), two independent prognostic tests in the assessment of patients with coronary artery disease.

METHODS

The cohort consisted of patients who had clinically indicated exercise stress testing and CACS assessment from January 1, 2015, to September 30, 2021, with a median of 27 days between each other. Exercise capacity was defined by peak metabolic equivalents of task (METs) achieved during exercise stress test. The CACS was determined by the Agatston method. Patients were observed from the latest test date to incident major adverse cardiac events (inclusive of all-cause death, nonfatal myocardial infarction, late revascularization, and admission for heart failure).

RESULTS

There were a` total of 1932 patients in the study population (mean age, 56±12 years; 42% female, 48% hypertension, 21% diabetes, 48% dyslipidemia). Peak METs below 6 was achieved in 8% of patients, and the median (interquartile range) CACS was 9 (0-203). In multivariable Cox regression models, both CACS (1 unit increase in log CACS: hazard ratio, 1.19; 95% CI, 1.06 to 1.34; P=.003;) and EC (1 unit increase in peak METs: hazard ratio, 0.89; 95% CI, 0.81 to 0.97; P=.01) were independently associated with outcomes. Using CACS+EC added incremental prognostic value over clinical and fitness models (C index increase from 0.68 to 0.75; P=.015). Incident event rates increased across categories of CACS and EC.

CONCLUSION

Our analysis found that CACS and EC have complementary risk-stratifying roles in coronary artery disease.

Diagnostic accuracy of FDG PET for the identification of Vascular Graft Infection

BACKGROUND

Fluorodeoxyglucose (FDG) positron emission tomography (FDG PET/CT) can be used to identify and localize infection in patients with vascular graft infections (VGI). We aimed to evaluate the diagnostic accuracy of 18F-FDG PET/CT by defining thresholds for standardized uptake value (SUV) and tissue-to-background ratio (TBR) that would accurately identify the presence of vascular graft infection.

METHODS

Patients with suspected VGI were prospectively recruited and underwent 18F-FDG PET/CT scans. Diagnosis was based on clinical, laboratory and radiologic findings, and blinded to the results of the PET/CT scan. Receiver operator characteristics (ROC) curve analysis was done to determine optimal thresholds for SUV and TBR.

RESULTS

Our final cohort consisted of 28 patients with suspected VGI (mean±SD age 67±10 years, 61% men), of which 15 patients (54%) had definitive VGI. The cohort included 61% prosthetics grafts and 39% stent-grafts. The type of graft included in this study were biologic (4%), Dacron (64%) and Polytetrafluoroethylene (32%). The location of the implanted grafts were aortic (54%) and peripheral arterial reconstruction (46%). The location of the peripheral graft was 77% in lower extremity and 23% in the upper extremity (arterio-venous grafts for dialysis access). Using ROC analysis, SUV max of 4.5, SUV mean of 3.7, and a TBR of 1.6 gave the best balance between sensitivity and specificity (93%/92%, 100%/92% and 93%/92% respectively). All thresholds had an area under the curve ≥0.93 and correct reclassification rate ≥93%.

CONCLUSION

Our data suggests that FDG PET/CT can be used to reliably and accurately diagnose VGI. The dual anatomic-physiologic information from FDG PET/CT can complement clinical diagnosis particularly in uncertain cases.

Outcomes of patients with moderate-to-severe Ischemia excluded from the ischemia trial

BACKGROUND

The International Study of Comparative Health Effectiveness with Medical and Invasive Approaches (ISCHEMIA) trial showed no difference in outcomes between medical therapy vs coronary revascularization in the management of patients with stable coronary artery disease. We aimed to determine the percentage of patients with at least moderate ischemia that would have been eligible for enrollment and evaluate the outcomes of those who would not.

METHODS

Consecutive patients who underwent cardiac single-photon emission computed tomography (SPECT) between April 2016 and September 2019 were identified and all-cause mortality was determined.

RESULTS

There were a total of 1508 patients (mean age 67 ± 11.6 years, 69.5% males) with any perfusion defect on SPECT. Patients had a high prevalence of cardiac risk factors (73.4% with hypertension and 54.4% with diabetes mellitus.) Nearly half (709, 47%) had moderate-to-severe ischemia but over two-thirds (479/709, 66.3%) had at least one ISCHEMIA trial exclusion criteria. Patients meeting ISCHEMIA enrollment criteria had a significantly lower all-cause mortality than those who would have been excluded (3.91% vs. 11.3%, respectively, P < .001).

CONCLUSION

Our results show that ISCHEMIA selected a relatively small subset of lower risk patients among the larger higher risk group of patients with moderate-to-severe ischemia typical to most cardiology centers.

Added Prognostic Value of Plaque Burden to Computed Tomography Angiography and Myocardial Perfusion Imaging in Patients with Diabetes

BACKGROUND

We aimed to compare the added prognostic value of plaque burden to cardiac computed tomographic angiography (CCTA) anatomic assessment and single-photon emission computed tomography (SPECT) physiologic assessment in patients with diabetes undergoing both tests.

METHODS

Consecutive patients with diabetes who underwent clinically indicated CCTA and SPECT myocardial imaging for suspected coronary artery disease were included. Stenosis severity and segment involvement score (SIS) were determined from CCTA, and presence of ischemia was determined from SPECT. Patients were followed from date of imaging for major adverse cardiovascular events (MACE).

RESULTS

A total of 778 patients were included (mean age 60.6 ± 14.4 years, 55% males). After a median follow-up of 31 months, 87 (11%) patients experienced a MACE. In multivariable Cox regression models, SIS significantly predicted outcomes in models including obstructive stenosis and ischemia (hazard ratio 1.17, 95% confidence interval 1.10-1.24, P < .001; hazard ratio 1.16, 95% confidence interval 1.10-1.23, P < .001, respectively), and improved discrimination (Harrel's C 0.75, P = .006; 0.76, P = .006 in models with CCTA obstructive stenosis and SPECT ischemia, respectively). Results were consistent using subgroups of summed scores by composition of plaque (calcified vs noncalcified) and alternate definitions of obstructive stenosis.

CONCLUSION

Our results suggest that in high-risk patients with diabetes and suspected coronary disease, SIS has incremental prognostic value over ischemia by SPECT or stenosis by CCTA in predicting incident cardiovascular outcomes.

Aspirin and Statin Therapy for Nonobstructive Coronary Artery Disease: Five-year Outcomes from the CONFIRM Registry

Purpose

In this cohort study, 5-year data from the Coronary CT Angiography Evaluation for Clinical Outcomes: An International Multicenter Registry (ie, CONFIRM) were examined to identify associations of baseline aspirin and statin use with mortality, major adverse cardiovascular events (MACE), and myocardial infarction (MI) in individuals without substantial (≥50%) stenosis.

Materials and Methods

In this prospective cohort study, all participants in the registry underwent coronary CT angiography and were classified as having no detectable coronary plaque or having nonobstructive coronary artery disease (CAD) (1%-49% stenosis). Participants with obstructive (≥50%) stenosis were excluded from analysis. The study commenced in June 2003 and was completed in March 2016. All unadjusted and risk-adjusted analyses utilized the Cox proportional hazard model with hospital sites modeled using shared frailty.

Results

A total of 6386 participants with no detectable plaque or with nonobstructive CAD were included (mean age, 56.0 years ± 13.3 [SD], 52% men). The mean follow-up period was 5.66 years ± 1.10. Nonobstructive CAD (n = 2815, 44% of all participants included in the study) was associated with a greater risk of all-cause mortality (10.6% [298 of 2815] vs 4.8% [170 of 3571], P < .001) compared to those without CAD (n = 3571, 56%). Baseline aspirin and statin use was documented for 1415 and 1429 participants, respectively, with nonobstructive CAD, and for 1560 and 1565 participants without detectable plaque, respectively. In individuals with nonobstructive CAD, baseline aspirin use was not associated with a reduction in MACE (10.9% [102 of 936] vs 14.7% [52 of 355], P = .06), all-cause mortality (9.6% [95 of 991] vs 10.9% [46 of 424], P = .468), or MI (4.4% [41 of 936] vs 6.2% [22 of 355], P = .18). On multivariate risk-adjusted analysis, baseline statin use was associated with a lower rate of MACE (hazard ratio, 0.59; 95% CI: 0.40, 0.87; P = .007). Neither therapy improved clinical outcomes for participants with no detectable plaque.

Conclusion

In participants with nonobstructive CAD, baseline use of statins, but not of aspirin, was associated with improved clinical outcomes. Neither therapy was associated with benefit in participants without plaque.Keywords: Aspirin, Statin, Coronary Artery Disease, CT Angiography, Nonobstructive Coronary Artery DiseaseClinical trial registration no. NCT01443637 Supplemental material is available for this article. © RSNA, 2022See also the commentary by Canan and Navar in this issue.

It Takes a Village: Multimodality Imaging of Cardiac Amyloidosis

Cardiac amyloidosis (CA) is the buildup and infiltration of amyloid plaque in cardiac muscle. An underdiagnosed form of restrictive cardiomyopathy, CA can rapidly progress into heart failure. CA is evaluated using a multimodality approach that includes echocardiography, cardiac magnetic imaging, and nuclear imaging. Echocardiography remains an essential first-line modality that raises suspicion for CA and establishes functional baselines. Cardiac magnetic imaging provides additional incremental value via high-resolution imaging, robust functional assessment, and superior tissue characterization, all of which enable a more comprehensive investigation of CA. Cardiac scintigraphy has eliminated the need for invasive diagnostic approaches and helps differentiate CA subtypes. Positron emission tomography is the first modality introducing targeted amyloid binding tracers that allow for precise burden quantification, early detection, and disease monitoring. In this review, we highlight the role of several cardiac imaging techniques in the evaluation of CA.

Cardiovascular magnetic resonance for suspected cardiac amyloidosis: where are we now?

Cardiac amyloidosis (CA) is an underdiagnosed form of restrictive cardiomyopathy leading to a rapid progression into heart failure. Evaluation of CA requires a multimodality approach making use of echocardiography, cardiac magnetic imaging (CMR), and nuclear imaging. With superior tissue characterization, high-resolution imaging, and precise cardiac assessment, CMR has emerged as a versatile tool in the workup of cardiac amyloidosis with a wide array of parameters both visual and quantitative. This includes late gadolinium enhancement patterns, T1/T2 mapping, and extracellular volume (ECV) measurement providing robust diagnostic accuracies, patient stratification, and prognostication. Recent advancements have introduced new measures able to identify early disease, track disease progression, and response to therapy positioning CMR as an instrumental imaging modality in the era of rising interest in CA screening and emerging effective therapies.

Cardiovascular risk profile of Middle Eastern immigrants living in the United States-the National Health Interview Survey

BACKGROUND

Middle Eastern (ME) immigrants are one of the fastest-growing groups in the US. Although ME countries have a high burden of atherosclerotic cardiovascular disease (ASCVD), the cardiovascular health status among ME immigrants in the US has not been studied in detail. This study aims to characterize the cardiovascular health status (CVD risk factors and ASCVD burden) among ME immigrants in the US.

METHODS

We used 2012-2018 data from the National Health Interview Survey, a US nationally representative survey. ME origin, CVD risk factors, and ASCVD status were self-reported. We compared these to US-born non-Hispanic white (NHW) individuals in the US.

RESULTS

Among 139,778 adults included, 886 (representing 1.3 million individuals, mean age 46.8) were of ME origin, and 138,892 were US-born NHWs (representing 150 million US adults, mean age 49.3). ME participants were more likely to have higher education, lower income and be uninsured. The age-adjusted prevalence of hypertension (22.4% vs 27.4%) and obesity (21.4% vs 31.4%) were significantly lower in ME vs NHW participants, respectively. There were no significant differences between the groups in the age-adjusted prevalence of ASCVD, diabetes, hyperlipidemia, and smoking. Only insufficient physical activity was higher among ME individuals. ME immigrants living in the US for 10 years or more reported higher age-adjusted prevalence of hypertension, hyperlipidemia, and ASCVD.

CONCLUSIONS

ME immigrants in the US have lower odds of hypertension and obesity, and of having a suboptimal CRF profile compared to US-born NHWs. Further studies are needed to determine whether these findings are related to lower risk, selection of a healthier ME subgroup in NHIS, or possible under-detection of cardiovascular risk factors in ME immigrants living in the US.

Association of Plaque Location and Vessel Geometry Determined by Coronary Computed Tomographic Angiography With Future Acute Coronary Syndrome-Causing Culprit Lesions

IMPORTANCE

Distinct plaque locations and vessel geometric features predispose to altered coronary flow hemodynamics. The association between these lesion-level characteristics assessed by coronary computed tomographic angiography (CCTA) and risk of future acute coronary syndrome (ACS) is unknown.

OBJECTIVE

To examine whether CCTA-derived adverse geometric characteristics (AGCs) of coronary lesions describing location and vessel geometry add to plaque morphology and burden for identifying culprit lesion precursors associated with future ACS.

DESIGN, SETTING, AND PARTICIPANTS

This substudy of ICONIC (Incident Coronary Syndromes Identified by Computed Tomography), a multicenter nested case-control cohort study, included patients with ACS and a culprit lesion precursor identified on baseline CCTA (n = 116) and propensity score-matched non-ACS controls (n = 116). Data were collected from July 20, 2012, to April 30, 2017, and analyzed from October 1, 2020, to October 31, 2021.

EXPOSURES

Coronary lesions were evaluated for the following 3 AGCs: (1) distance from the coronary ostium to lesion; (2) location at vessel bifurcations; and (3) vessel tortuosity, defined as the presence of 1 bend of greater than 90° or 3 curves of 45° to 90° using a 3-point angle within the lesion.

MAIN OUTCOMES AND MEASURES

Association between lesion-level AGCs and risk of future ACS-causing culprit lesions.

RESULTS

Of 548 lesions, 116 culprit lesion precursors were identified in 116 patients (80 [69.0%] men; mean [SD], age 62.7 [11.5] years). Compared with nonculprit lesions, culprit lesion precursors had a shorter distance from the ostium (median, 35.1 [IQR, 23.6-48.4] mm vs 44.5 [IQR, 28.2-70.8] mm), more frequently localized to bifurcations (85 [73.3%] vs 168 [38.9%]), and had more tortuous vessel segments (5 [4.3%] vs 6 [1.4%]; all P < .05). In multivariable Cox regression analysis, an increasing number of AGCs was associated with a greater risk of future culprit lesions (hazard ratio [HR] for 1 AGC, 2.90 [95% CI, 1.38-6.08]; P = .005; HR for ≥2 AGCs, 6.84 [95% CI, 3.33-14.04]; P < .001). Adverse geometric characteristics provided incremental discriminatory value for culprit lesion precursors when added to a model containing stenosis severity, adverse morphological plaque characteristics, and quantitative plaque characteristics (area under the curve, 0.766 [95% CI, 0.718-0.814] vs 0.733 [95% CI, 0.685-0.782]). In per-patient comparison, patients with ACS had a higher frequency of lesions with adverse plaque characteristics, AGCs, or both compared with control patients (≥2 adverse plaque characteristics, 70 [60.3%] vs 50 [43.1%]; ≥2 AGCs, 92 [79.3%] vs 60 [51.7%]; ≥2 of both, 37 [31.9%] vs 20 [17.2%]; all P < .05).

CONCLUSIONS AND RELEVANCE

These findings support the concept that CCTA-derived AGCs capturing lesion location and vessel geometry are associated with risk of future ACS-causing culprit lesions. Adverse geometric characteristics may provide additive prognostic information beyond plaque assessment in CCTA.

Interoperator reliability of an on-site machine learning-based prototype to estimate CT angiography-derived fractional flow reserve

BACKGROUND

Advances in CT and machine learning have enabled on-site non-invasive assessment of fractional flow reserve (FFR_CT).

PURPOSE

To assess the interoperator and intraoperator variability of coronary CT angiography-derived FFR_CT using a machine learning-based postprocessing prototype.

MATERIALS AND METHODS

We included 60 symptomatic patients who underwent coronary CT angiography. FFR_CT was calculated by two independent operators after training using a machine learning-based on-site prototype. FFR_CT was measured 1 cm distal to the coronary plaque or in the middle of the segments if no coronary lesions were present. Intraclass correlation coefficient (ICC) and Bland-Altman analysis were used to evaluate interoperator variability effect in FFR_CT estimates. Sensitivity analysis was done by cardiac risk factors, degree of stenosis and image quality.

RESULTS

A total of 535 coronary segments in 60 patients were assessed. The overall ICC was 0.986 per patient (95% CI 0.977 to 0.992) and 0.972 per segment (95% CI 0.967 to 0.977). The absolute mean difference in FFR_CT estimates was 0.012 per patient (95% CI for limits of agreement: -0.035 to 0.039) and 0.02 per segment (95% CI for limits of agreement: -0.077 to 0.080). Tight limits of agreement were seen on Bland-Altman analysis. Distal segments had greater variability compared with proximal/mid segments (absolute mean difference 0.011 vs 0.025, p<0.001). Results were similar on sensitivity analysis.

CONCLUSION

A high degree of interoperator and intraoperator reproducibility can be achieved by on-site machine learning-based FFR_CT assessment. Future research is required to evaluate the physiological relevance and prognostic value of FFR_CT.