Impact of myocardial perfusion and coronary calcium on medical management for coronary artery disease

AIMS

Single-photon emission computed tomography (SPECT) myocardial perfusion imaging (MPI) remains one of the most widely used imaging modalities for the diagnosis and prognostication of coronary artery disease (CAD). Despite the extensive prognostic information provided by MPI, little is known about how this influences the prescription of medical therapy for CAD. We evaluated the relationship between MPI with computed tomography (CT) attenuation correction and prescription of acetylsalicylic acid (ASA) and statins.

METHODS AND RESULTS

We performed a retrospective analysis of consecutive patients who underwent SPECT MPI at a single centre between 2015 and 2021. Myocardial perfusion abnormalities and coronary calcium burden were assessed, with attenuation correction imaging 77.8% of patients. Medication prescriptions before and within 180 days after the test were compared. Associations between abnormal perfusion and calcium burden with ASA and statin prescription were assessed using multivariable logistic regression. In total, 9908 patients were included, with a mean age 66.8 ± 11.7 years and 5337 (53.9%) males. The prescription of statins increased more in patients with abnormal perfusion (increase of 19.2 vs. 12.0%, P < 0.001). Similarly, the presence of extensive CAC led to a greater increase in statin prescription compared with no calcium (increase 12.1 vs. 7.8%, P < 0.001). In multivariable analyses, ischaemia and coronary artery calcium were independently associated with ASA and statin prescription.

CONCLUSION

Abnormal MPI testing was associated with significant changes in medical therapy. Both calcium burden and perfusion abnormalities were associated with increased prescriptions of medical therapy for CAD.

A treatment algorithm for ischemic cardiomyopathy

Treatment of ischemic cardiomyopathy has been the focus of increased attention by cardiologists due to recent evidence of an important outcome study comparing percutaneous coronary intervention (PCI) plus optimal medical treatment vs optimal medical treatment alone, concluding for the futility of myocardial revascularization by PCI. A relatively older trial of coronary artery bypass grafting (CABG) in the same condition, on the other hand, had concluded for some prognostic improvement at a long-term follow-up. This short manuscript addresses how to triage such patients, frequently encountered in medical practice and considering clinical presentation, imaging results, and surgical risk, to provide practical guidance to treatment.

Understanding the role of coronary artery revascularization in patients with left ventricular dysfunction and multivessel disease

Coronary artery disease (CAD) is the most common cause of heart failure with reduced ejection fraction (HFrEF). Advances and innovations in medical therapy have been shown to play a crucial role in improving the prognosis of patients with CAD and HFrEF; however, mortality rate in these patients remains high, and the role of surgical and/or percutaneous revascularization strategy is still debated. The Surgical Treatment for Ischemic Heart Failure (STICH) trial and the Revascularization for Ischemic Ventricular Dysfunction (REVIVED) trial have attempted to provide an answer to this issue. Nevertheless, the results of these two trials have generated further uncertainties. Their findings do not provide a definitive answer about the ideal clinical phenotype for surgical or percutaneous coronary revascularization and dispute the historical dogma on myocardial viability and the theory of myocardial hibernation, raising new questions about the proper selection of patients who are candidates for coronary revascularization. The aim of this review is to provide an overview on the actual available evidence of coronary artery revascularization in patients with CAD and left ventricular dysfunction and to suggest new insights on the proper selection and management strategies in this high-risk clinical setting.

Should we choose CT angiography first instead of SPECT/PET first for the diagnosis and management of coronary artery disease?

In patients presenting with chest pain, current guidelines recommend the use of coronary computed tomography angiography and single-photon emission tomography/positron emission tomography, both with equal class 1 indication and level of evidence A. There is no clear recommendation on which test should be used as a first-line test. The choice of the test should be based on individualized clinical risk assessment, patient characteristics, local expertise/availability, and patient preferences. In this context, it is fair to ask which non-invasive imaging test to choose. The debate reproduced in this article answers this question by summarizing the considerations in selecting present state-of-the-art criteria of the right test for the right patient to ensure efficient resource utilization, minimize unnecessary testing, and maximize diagnostic accuracy and therapeutic efficacy.

Deep Learning Coronary Artery Calcium Scores from SPECT/CT Attenuation Maps Improve Prediction of Major Adverse Cardiac Events

Low-dose ungated CT attenuation correction (CTAC) scans are commonly obtained with SPECT/CT myocardial perfusion imaging. Despite the characteristically low image quality of CTAC, deep learning (DL) can potentially quantify coronary artery calcium (CAC) from these scans in an automatic manner. We evaluated CAC quantification derived with a DL model, including correlation with expert annotations and associations with major adverse cardiovascular events (MACE). Methods: We trained a convolutional long short-term memory DL model to automatically quantify CAC on CTAC scans using 6,608 studies (2 centers) and evaluated the model in an external cohort of patients without known coronary artery disease (n = 2,271) obtained in a separate center. We assessed agreement between DL and expert annotated CAC scores. We also assessed associations between MACE (death, revascularization, myocardial infarction, or unstable angina) and CAC categories (0, 1-100, 101-400, or >400) for scores manually derived by experienced readers and scores obtained fully automatically by DL using multivariable Cox models (adjusted for age, sex, past medical history, perfusion, and ejection fraction) and net reclassification index. Results: In the external testing population, DL CAC was 0 in 908 patients (40.0%), 1-100 in 596 (26.2%), 100-400 in 354 (15.6%), and >400 in 413 (18.2%). Agreement in CAC category by DL CAC and expert annotation was excellent (linear weighted κ, 0.80), but DL CAC was obtained automatically in less than 2 s compared with about 2.5 min for expert CAC. DL CAC category was an independent risk factor for MACE with hazard ratios in comparison to a CAC of zero: CAC of 1-100 (2.20; 95% CI, 1.54-3.14; P < 0.001), CAC of 101-400 (4.58; 95% CI, 3.23-6.48; P < 0.001), and CAC of more than 400 (5.92; 95% CI, 4.27-8.22; P < 0.001). Overall, the net reclassification index was 0.494 for DL CAC, which was similar to expert annotated CAC (0.503). Conclusion: DL CAC from SPECT/CT attenuation maps agrees well with expert CAC annotations and provides a similar risk stratification but can be obtained automatically. DL CAC scores improved classification of a significant proportion of patients as compared with SPECT myocardial perfusion alone.

Myocardial Revascularization in Patients With Ischemic Cardiomyopathy: For Whom and How

Background Myocardial revascularization has been advocated to improve myocardial function and prognosis in ischemic cardiomyopathy (ICM). We discuss the evidence for revascularization in patients with ICM and the role of ischemia and viability detection in guiding treatment. Methods and Results We searched for randomized controlled trials evaluating the prognostic impact of revascularization in ICM and the value of viability imaging for patient management. Out of 1397 publications, 4 randomized controlled trials were included, enrolling 2480 patients. Three trials (HEART [Heart Failure Revascularisation Trial], STICH [Surgical Treatment for Ischemic Heart Failure], and REVIVED [REVascularization for Ischemic VEntricular Dysfunction]-BCIS2) randomized patients to revascularization or optimal medical therapy. HEART was stopped prematurely without showing any significant difference between treatment strategies. STICH showed a 16% lower mortality with bypass surgery compared with optimal medical therapy at a median follow-up of 9.8 years. However, neither the presence/extent of left ventricle viability nor ischemia interacted with treatment outcomes. REVIVED-BCIS2 showed no difference in the primary end point between percutaneous revascularization or optimal medical therapy. PARR-2 (Positron Emission Tomography and Recovery Following Revascularization) randomized patients to imaging-guided revascularization versus standard care, with neutral results overall. Information regarding the consistency of patient management with viability testing results was available in ≈65% of patients (n=1623). No difference in survival was revealed according to adherence or no adherence to viability imaging. Conclusions In ICM, the largest randomized controlled trial, STICH, suggests that surgical revascularization improves patients' prognosis at long-term follow-up, whereas evidence supports no benefit of percutaneous coronary intervention. Data from randomized controlled trials do not support myocardial ischemia or viability testing for treatment guidance. We propose an algorithm for the workup of patients with ICM considering clinical presentation, imaging results, and surgical risk.

Development and validation of ischemia risk scores

BACKGROUND

The likelihood of ischemia on myocardial perfusion imaging is central to physician decisions regarding test selection, but dedicated risk scores are lacking. We derived and validated two novel ischemia risk scores to support physician decision making.

METHODS

Risk scores were derived using 15,186 patients and validated with 2,995 patients from a different center. Logistic regression was used to assess associations with ischemia to derive point-based and calculated ischemia scores. Predictive performance for ischemia was assessed using area under the receiver operating characteristic curve (AUC) and compared with the CAD consortium basic and clinical models.

RESULTS

During derivation, the calculated ischemia risk score (0.801) had higher AUC compared to the point-based score (0.786, p < 0.001). During validation, the calculated ischemia score (0.716, 95% CI 0.684- 0.748) had higher AUC compared to the point-based ischemia score (0.699, 95% CI 0.666- 0.732, p = 0.016) and the clinical CAD model (AUC 0.667, 95% CI 0.633- 0.701, p = 0.002). Calibration for both ischemia scores was good in both populations (Brier score  < 0.100).

CONCLUSIONS

We developed two novel risk scores for predicting probability of ischemia on MPI which demonstrated high accuracy during model derivation and in external testing. These scores could support physician decisions regarding diagnostic testing strategies.

Direct Risk Assessment From Myocardial Perfusion Imaging Using Explainable Deep Learning

BACKGROUND

Myocardial perfusion imaging (MPI) is frequently used to provide risk stratification, but methods to improve the accuracy of these predictions are needed.

OBJECTIVES

The authors developed an explainable deep learning (DL) model (HARD MACE [major adverse cardiac events]-DL) for the prediction of death or nonfatal myocardial infarction (MI) and validated its performance in large internal and external testing groups.

METHODS

Patients undergoing single-photon emission computed tomography MPI were included, with 20,401 patients in the training and internal testing group (5 sites) and 9,019 in the external testing group (2 different sites). HARD MACE-DL uses myocardial perfusion, motion, thickening, and phase polar maps combined with age, sex, and cardiac volumes. The primary outcome was all-cause mortality or nonfatal MI. Prognostic accuracy was evaluated using area under the receiver-operating characteristic curve (AUC).

RESULTS

During internal testing, patients with normal perfusion and elevated HARD MACE-DL risk were at higher risk than patients with abnormal perfusion and low HARD MACE-DL risk (annualized event rate, 2.9% vs 1.2%; P < 0.001). Patients in the highest quartile of HARD MACE-DL score had an annual rate of death or MI (4.8%) 10-fold higher than patients in the lowest quartile (0.48% per year). In external testing, the AUC for HARD MACE-DL (0.73; 95% CI: 0.71-0.75) was higher than a logistic regression model (AUC: 0.70), stress total perfusion deficit (TPD) (AUC: 0.65), and ischemic TPD (AUC: 0.63; all P < 0.01). Calibration, a measure of how well predicted risk matches actual risk, was excellent in both groups (Brier score, 0.079 for internal and 0.070 for external).

CONCLUSIONS

The DL model predicts death or MI directly from MPI, by estimating patient-level risk with good calibration and improved accuracy compared with traditional quantitative approaches. The model incorporates mechanisms to explain to the physician which image regions contribute to the adverse event prediction.

What Is New in Risk Assessment in Nuclear Cardiology?

Nuclear cardiology techniques allow in-depth evaluation of cardiac patients. A body of literature has established the use of nuclear cardiology. The results obtained with traditional cameras have been reinforced by those obtained with a series of innovations that have revolutionized the field of nuclear cardiology. This article highlights the role of nuclear cardiology in the risk assessment of patients with cardiac disease and sheds light on advancements of nuclear imaging techniques in the cardiovascular field. Patient risk stratification has a key role in modern precision medicine. Nuclear cardiac imaging techniques may quantitatively investigate major disease mechanisms of different cardiac pathologies.

Sex-specific associations of myocardial perfusion imaging with outcomes in patients with suspected chronic coronary syndrome

BACKGROUND

Myocardial perfusion scintigraphy (MPS) is an established diagnostic technique for inducible ischemia in patients with suspected chronic coronary syndrome (CCS). Some MPS findings, most notably an ischemia extent>10% of the left ventricle (LV), hold prognostic significance and support maximization of anti-ischemic treatment. We aimed to assess sex-specific associations of MPS findings with cardiovascular (CV) events in a population at high risk of CCS.

METHODS

In a prospective cohort study, 1,229 consecutive patients (age 70 ± 9.5 years, 73.5% males) without known CCS were referred to stress-rest MPS. All patients were followed for a median of 4.6 years for CV events.

RESULTS

Men and women had comparable risk profiles and incidence rates of CV events (6.6% vs. 4.6% respectively, P = 0.186). A summed stress score (SSS) > 7 was associated with the primary endpoint, including CV death and/or nonfatal myocardial infarction (MI) (adjusted hazard ratio [HR], 3.13; 95% confidence interval [CI], 1.79-5.46; P = 0.001), all-cause mortality (HR, 3.01; 95% CI, 1.31-6.93; P = 0.01), and incidence of late revascularization (HR, 1.84; 95% CI, 1.22-2.78; P = 0.004) in men but not women. A summed difference score (SDS) > 6 was related to a higher rate of the primary endpoint only in men (adjusted HR, 1.97; 95% CI, 1.18-3.30; P = 0.009).

CONCLUSIONS

Among patients undergoing a diagnostic workup for suspected CCS, stress perfusion and reversible ischemia abnormalities may independently predict worse survival and more CV events in men. However, the obtained results indicated the need for sex-specific cutoffs to refine risk stratification and assist in clinical decisions on anti-ischemic therapy beyond coronary artery anatomy.

Long-term Survival Benefit From Revascularization Compared With Medical Therapy in Patients With or Without Diabetes Undergoing Myocardial Perfusion Single Photon Emission Computed Tomography

OBJECTIVE

To explore the long-term association of survival benefit from early revascularization with the magnitude of ischemia in patients with diabetes compared with those without diabetes using a large observational cohort of patients undergoing single photon emission computed tomography myocardial perfusion imaging (SPECT-MPI).

RESEARCH DESIGN AND METHODS

Of 41,982 patients who underwent stress and rest SPECT-MPI from 1998 to 2017, 8,328 (19.8%) had diabetes. A propensity score was used to match 8,046 patients with diabetes to 8,046 patients without diabetes. Early revascularization was defined as occurring within 90 days after SPECT-MPI. The percentage of myocardial ischemia was assessed from the magnitude of reversible myocardial perfusion defect on SPECT-MPI.

RESULTS

Over a median 10.3-year follow-up, the annualized mortality rate was higher for the patients with diabetes compared with those without diabetes (4.7 vs. 3.6%; P < 0.001). There were significant interactions between early revascularization and percent myocardial ischemia in patients with and without diabetes (all interaction P values <0.05). After adjusting for confounding variables, survival benefit from early revascularization was observed in patients with diabetes above a threshold of >8.6% ischemia and in patients without diabetes above a threshold of >12.1%. Patients with diabetes receiving insulin had a higher mortality rate (6.2 vs. 4.1%; P < 0.001), but there was no interaction between revascularization and insulin use (interaction P value = 0.405).

CONCLUSIONS

Patients with diabetes, especially those on insulin treatment, had higher mortality rate compared with patients without diabetes. Early revascularization was associated with a mortality benefit at a lower ischemic threshold in patients with diabetes compared with those without diabetes.

Benefit of Early Revascularization Based on Inducible Ischemia and Left Ventricular Ejection Fraction

BACKGROUND

The utility of performing early myocardial revascularization among patients presenting with inducible myocardial ischemia and low left ventricular ejection fraction (LVEF) is currently unknown.

OBJECTIVES

In this study, we sought to assess the relationship between stress-induced myocardial ischemia, revascularization, and all-cause mortality (ACM) among patients with normal vs low LVEF.

METHODS

We evaluated 43,443 patients undergoing stress-rest single-photon emission computed tomography myocardial perfusion imaging from 1998 to 2017. Median follow-up was 11.4 years. Myocardial ischemia was assessed for its interaction between early revascularization and mortality. A propensity score was used to adjust for nonrandomization to revascularization, followed by multivariable Cox modeling adjusted for the propensity score and clinical variables to predict ACM.

RESULTS

The frequency of myocardial ischemia varied markedly according to LVEF and angina, ranging from 6.7% among patients with LVEF ≥55% and no typical angina to 64.0% among patients with LVEF <45% and typical angina (P < 0.001). Among 39,883 patients with LVEF ≥45%, early revascularization was associated with increased mortality risk among patients without ischemia and lower mortality risk among patients with severe (≥15%) ischemia (HR: 0.70; 95% CI: 0.52-0.95). Among 3,560 patients with LVEF <45%, revascularization was not associated with mortality benefit among patients with no or mild ischemia, and was associated with decreased mortality among patients with moderate (10%-14%) (HR: 0.67; 95% CI: 0.49-0.91) and severe (≥15%) (HR: 0.55; 95% CI: 0.38-0.80) ischemia.

CONCLUSIONS

Within this cohort, early myocardial revascularization was associated with a significant reduction in mortality among both patients with normal LVEF and severe inducible myocardial ischemia and patients with low LVEF and moderate or severe inducible myocardial ischemia.

Mortality in Stable Coronary Disease in Patients With Intermediate- or High-Risk Myocardial Perfusion Imaging

The management of patients with stable coronary disease and intermediate- or high-risk features on single photon emission computed tomography myocardial perfusion imaging (SPECT MPI) continues to be controversial as to whether they should be treated with an initial invasive strategy (catheterization and revascularization when feasible) or medical therapy alone to improve mortality. We performed a retrospective observational study of 1,946 patients with intermediate- or high-risk SPECT MPI scans performed over a 6-year period (from 2014 to 2019). Each patient was followed from the time of SPECT MPI to 16 months after the last patient was enrolled. The primary end point was all-cause mortality and the secondary end point cardiovascular mortality. Of the eligible 1,697 patients, 1,144 had an intermediate-risk scan, 553 a high-risk scan, 915 had medical therapy alone, and 782 went on an initial invasive strategy. All patients were divided into the following three groups: combined SPECT MPI (both intermediate- and high-risk), high-risk SPECT MPI, and intermediate-risk SPECT MPI groups. After propensity score matching, there was a statistically significant difference in cardiovascular death (5.9% vs 2.7%; p = 0.038) in the medical therapy cohort compared with initial invasive cohort in the combined SPECT MPI group, but no difference in all-cause death (15.7% vs 13%; p = 0.318). On subgroup analysis, in intermediate-risk SPECT MPI group, there was no significant difference in either all-cause death (13.8 vs 11.7%; p = 0.583) or cardiac death (5.4% vs 2.5%; p = 0.16) in conservative cohort compared with invasive strategy cohort. In high-risk SPECT MPI group, conservative therapy cohort had higher cardiac death (11.7% vs 2.5%; p = 0.002) compared with initial invasive strategy cohort, but there was no significant difference in all-cause death (24.5% vs 15.3%; p = 0.052). In conclusion, this study supports that patients with intermediate- or high-risk SPECT MPI scans when considered together or only with high-risk features, derive a cardiovascular mortality benefit with an initial invasive strategy. Patients who had undergone intermediate-risk SPECT MPI had similar outcomes with either medical therapy alone or initial invasive evaluation.

Coronary Revascularization in Patients With Stable Coronary Artery Disease: The Role of Imaging

In the last decades, the effective management of some cardiovascular risk factors in the general population has led to a progressive decrease in the prevalence of coronary artery disease (CAD). Nevertheless, coronary heart disease remains the major cause of death in developed and developing countries and chronic coronary syndromes (CCS) are still a major target of utilization of non-invasive cardiac imaging and invasive procedures. Current guidelines recommend the use of non-invasive imaging in patients with CCS to identify subjects at higher risk to be referred for invasive coronary angiography and possible revascularization. These recommendations are challenged by two opposite lines of evidence. Recent trials have somewhat questioned the efficacy of coronary revascularization as compared with optimal medical therapy in CCS. As a consequence the role of imaging in these patients and in in patients with ischemic cardiomyopathy is under debate. On the other hand, real-life data indicate that a consistent proportion of patients undergo invasive procedure and are revascularized without any previous non-invasive imaging characterization. On top of this, the impact of COVID-19 pandemic on the sanitary systems caused a change in the current management of patients with CAD. In the present review we will discuss these conflicting data analyzing the evidence which has been recently accumulated as well as the gaps of knowledge which should still be filled.

Long-Term Prognostic Value of Stress Cardiovascular Magnetic Resonance-Related Coronary Revascularization to Predict Death: A Large Registry With >200 000 Patient-Years of Follow-Up

BACKGROUND

Although the benefit of coronary revascularization in patients with stable coronary disease is debated, data assessing the potential interest of stress cardiovascular magnetic resonance (CMR) to guide coronary revascularization are limited. We aimed to assess the long-term prognostic value of stress CMR-related coronary revascularization in consecutive patients from a large registry.

METHODS

Between 2008 and 2018, a retrospective cohort study with a median follow-up of 6.0 years (interquartile range, 5.0-8.0) included all consecutive patients referred for stress CMR. CMR-related coronary revascularization was defined by any coronary revascularization performed within 90 days after CMR. The primary outcome was all-cause death based on the National Death Registry.

RESULTS

Among the 31 762 consecutive patients (mean age 63.7±12.1 years and 65.7% males), 2679 (8.4%) died at 206 453 patient-years of follow-up. Inducible ischemia and late gadolinium enhancement by CMR were associated with death (both P<0.001). In multivariable Cox regression, inducible ischemia and late gadolinium enhancement were independent predictors of death (hazard ratio, 1.61 [99.5% CI, 1.41-1.84]; hazard ratio, 1.62 [99.5% CI, 1.41-1.86], respectively; P<0.001). In the overall population, CMR-related coronary revascularization was an independent predictor of greater survival (hazard ratio, 0.58 [99.5% CI, 0.46-0.74]; P<0.001). In 1680, 1:1 matched patients using a limited number of variables (840 revascularized, 840 nonrevascularized), CMR-related revascularization was associated with a lower incidence of death in patients with severe inducible ischemia (≥6 segments, P<0.001) but showed no benefit in patients with mild or moderate ischemia (<6 segments, P=0.109). Using multivariable analysis in the propensity-matched population, CMR-related revascularization remained an independent predictor of a lower incidence of all-cause mortality (hazard ratio, 0.66 [99.5% CI, 0.54-0.80], P<0.001).

CONCLUSIONS

In this large observational series of consecutive patients, stress perfusion CMR had important incremental long-term prognostic value to predict death over traditional risk factors. CMR-related revascularization was associated with a lower incidence of death in patients with severe ischemia.

Cardiac Surgery 2020 Reviewed

In 2020, nearly 30,000 published references appeared in the PubMed for the search term "cardiac surgery." While SARS-CoV-2 affected the number of surgical procedures, it did not affect outcomes reporting. Using the PRISMA approach, we selected relevant publications and prepared a results-oriented summary. We reviewed primarily the fields of coronary and conventional valve surgery and their overlap with interventional alternatives. The coronary field started with a discussion on trial data value and their interpretation. Registry comparisons of coronary artery bypass surgery (CABG) and percutaneous coronary intervention confirmed outcomes for severe coronary artery disease and advanced comorbidities with CABG. Multiple arterial grafting was best. In aortic valve surgery, meta-analyses of randomized trials report that transcatheter aortic valve implantation may provide a short-term advantage but long-term survival may be better with classic aortic valve replacement (AVR). Minimally invasive AVR and decellularized homografts emerged as hopeful techniques. In mitral and tricuspid valve surgery, excellent perioperative and long-term outcomes were presented for structural mitral regurgitation. For both, coronary and valve surgery, outcomes are strongly dependent on surgeon expertise. Kidney disease increases perioperative risk, but does not limit the surgical treatment effect. Finally, a cursory look is thrown on aortic, transplant, and assist-device surgery with a glimpse into the current stand of xenotransplantation. As in recent years, this article summarizes publications perceived as important by us. It does not expect to be complete and cannot be free of individual interpretation. We aimed to provide up-to-date information for decision-making and patient information.

Improving Terminology to Describe Coronary Artery Procedures: JACC Review Topic of the Week

Coronary artery disease (CAD) is treated with medical therapy with or without percutaneous coronary intervention (PCI) or coronary artery bypass grafting (CABG). The latter 2 options are commonly referred to as "myocardial revascularization" procedures. We reason that this term is inappropriate because it is suggestive of a single treatment effect of PCI and CABG (ie, the reestablishment of blood flow to ischemic myocardium) and obscures key mechanisms, such as the improvement in coronary flow capability in the absence of ongoing ischemia, the reperfusion in the presence of ischemia, and the prevention of myocardial infarction from CAD progression. We review the current evidence on the topic and suggest the use of a purely descriptive terminology ("invasive treatment by PCI or CABG") which has the potential to improve clinical decision making and guide future trial design.

Visually estimated coronary artery calcium score improves SPECT-MPI risk stratification

Aims

Computed tomographic attenuation correction (CTAC) scans for single photon emission computed tomography myocardial perfusion imaging (SPECT-MPI) may reveal coronary artery calcification. The independent prognostic value of a visually estimated coronary artery calcium score (VECACS) from these low-dose, non-gated scans is not established.

Methods & Results

VECACS was evaluated in 4,720 patients undergoing SPECT-MPI with CTAC using a 4-point scale. Major adverse cardiac events (MACE) were defined as all-cause mortality, acute coronary syndrome, or revascularization > 90 days after SPECT-MPI. Independent associations with MACE were determined with multivariable Cox proportional hazards analyses adjusted for age, sex, past medical history, perfusion findings, and left ventricular ejection fraction. During a median follow up of 2.9 years (interquartile range 1.8 - 4.2), 494 (10.5%) patients experienced MACE. Compared to absent VECACS, patients with increased VECACS were more likely to experience MACE (all log-rank p < 0.001), and findings were similar when stratified by normal or abnormal perfusion. Multivariable analysis showed an increased MACE risk associated with VECACS categories of equivocal (adjusted hazard ratio [HR] 2.54, 95% CI 1.45-4.45, p = 0.001), present (adjusted HR 2.44, 95% CI 1.74-3.42, p < 0.001) and extensive (adjusted HR 3.47, 95% CI 2.41-5.00, p < 0.001) compared to absent. Addition of VECACS to the multivariable model improved risk classification (continuous net reclassification index 0.207, 95% CI 0.131 - 0.310).

Conclusion

VECACS was an independent predictor of MACE in this large SPECT-MPI patient cohort. VECACS from CTAC can be used to improve risk stratification with SPECT-MPI without additional radiation.

[Should i treat a high risk chronic coronary syndrome invasively from the beginning? Yes, in most cases]

Chronic coronary syndrome (SCC) previously known as stable coronary disease, is the main cause of mortality in the world, and it is one of the most important in Peru. This pathology has a dynamic nature that results in different clinical scenarios that can be modified through various therapeutic options, one of which is coronary interventional treatment, mainly in patients with high ischemic risk defined as ischemia greater than 10% of the entire left ventricular mass. For this reason, we have analyzed the most relevant and current information available, concluding that the treatment of high ischemic risk´s chronic coronary syndrome, after an individual evaluation, would correspond to an invasive management from the beginning, although it would not impact on mortality or cardiovascular events, it would contribute to improve quality of life; also we should consider the incomplete availability of all the therapeutic options for the symptomatic management of this disease, the limited access to the management of acute cardiovascular events in our country, as well as the risk of adverse effects and drug interactions.

[Should I treat a high-risk chronic coronary syndrome in an invasive way from the beginning? No, in most cases]

The definition of the high-risk chronic coronary syndrome varies depending on the noninvasive test used to trigger ischemia. The triggering occurs through increased myocardial work and oxygen demand, either through exercise or drugs. The initial approach to the chronic coronary syndrome leads us to discuss in which cases to prioritize an optimal initial medical therapy or to perform an initial invasive procedure of myocardial revascularization. In this article, we analyze both approaches based on previous studies carried out to date, where the initial invasive management has not been shown to be superior to initial optimal medical therapy in outcomes such as death or major adverse cardiovascular events.