Comparison of guidelines for diagnosing suspected stable angina and the additional value of the calcium score.

Background The performance of current diagnostic algorithms of the American College of Cardiology/American Heart Association (ACC/AHA), National Institute for Health and Care Excellence (NICE) and European Society of Cardiology (ESC) in patients with stable chest pain and coronary artery calcium (CAC) remains a matter of debate. We compared their merits in patients with CAC and investigated the additional value of the CAC score to improve diagnostic accuracy and risk stratification. Methods and results Patient data were obtained from a prospective registry of 642 consecutive patients. Mean age 63 (SD 11) years, 50% male. According to the guidelines, low and intermediate/high pre-test probability groups were constructed. Patients were reclassified based on their CAC score. Obstructive coronary artery disease (CAD) was observed in 14%. All models performed modestly in accurately predicting CAD (c-statistic <0.65). After addition of the CAC score, the c-statistic of the NICE model increased to 0.75 (95% confidence interval (CI) 0.73-0.78) which was just non-significant compared to the ESC model (0.71 95% CI 0.67-0.74) and performed significantly better than ACC/AHA (0.68 (95% CI 0.64-0.72)). After reclassification more than 50% of patients were classified low risk in NICE and ESC, while the prevalence of obstructive CAD (4.8% and 5.2% respectively) did not increase. Conclusions Addition of the CAC score to the studied models improved the ability to safely rule-out obstructive CAD and identified other patients at high risk for future coronary artery events. These results suggest that incorporating CAC score will lead to substantially less downstream testing and lower costs.

Stress-Only Adenosine CMR Improves Diagnostic Yield in Stable Symptomatic Patients With Coronary Artery Calcium.

OBJECTIVES: This study assessed whether adenosine stress-only perfusion cardiac magnetic resonance (CMR) following a positive coronary artery calcium (CAC) score improved the diagnostic yield of invasive coronary angiography (CAG) in patients with stable chest pain. The study also established the association between positive CAC scores and stress-induced myocardial ischemia. BACKGROUND: The diagnostic yield of catheterization among patients with suspected coronary artery disease (CAD) is low. Improved patient selection and diagnostic testing are necessary. The CAC score can minimize unnecessary diagnostic testing, and in low-risk patients, normal CMR results have a high negative predictive value. Less comprehensive protocols may be sufficient to guide further work-up. METHODS: A total of 642 consecutive patients (mean age: 63 years; 50% women) with stable chest pain and CAC scores of >0 who were referred for CMR were enrolled. Patients with a perfusion defect were subsequently examined by CAG. Patients were followed up for 1 year. Outcome was obstructive CAD. RESULTS: Obstructive CAD was present in 12% of patients. For CAD diagnosis, the sensitivity of adenosine CMR was 90.9% (95% confidence interval [CI]: 88.7 to 93.1), specificity was 98.7% (95% CI: 97.9 to 99.6), positive predictive value was 92.0% (95% CI: 89.8 to 94.1), and negative predictive value was 98.6% (95% CI: 97.6 to 99.5). A CAC score between 0.1 and 100 without typical angina was associated with obstructive CAD in only 3% of patients. Patients with nonanginal chest pain and a CAC score ≥400 had obstructive CAD (16%). CONCLUSIONS: Stress-only adenosine CMR had high diagnostic accuracy and served as an efficient gatekeeper to CAG in stable patients with a CAC score >0. Patients with CAC scores between 0.1 and 100 could be deferred from further testing in the absence of clinical features that suggested high risk. However, in patients with CAC score ≥400, functional testing should be indicated, regardless of the type of chest pain.

Prognostic value of coronary artery calcium score in symptomatic individuals: A meta-analysis of 34,000 subjects.

BACKGROUND: Coronary artery calcium (CAC) scanning has evolved into an important subclinical prediction method for cardiovascular diseases in asymptomatic subjects. However, the prognostic implication of CAC scanning in symptomatic individuals is less clear. OBJECTIVES: To assess the prognostic utility of CAC in predicting risk of major adverse cardiac events (MACE) in stable patients with suspected CAD. METHODS: We did a systematic electronic literature search for studies presenting original data in CAC score, and reporting cardiovascular events in stable, symptomatic patients as primary outcome. Primary outcome of the meta-analysis was the occurrence of MACE, a composite of late coronary revascularization, hospitalization for unstable angina or heart failure, nonfatal myocardial infarction, and cardiac death or all-cause mortality. Using random effects models, we pooled relative risk ratios of CAC for MACE, and adjusted hazard ratios (HR) of the associations between different CAC strata (CAC 0-100,100-400, and ≥ 400, versus CAC = 0) and incident MACE. RESULTS: We included 19 observational studies (n = 34,041). In total, 1601 events were analyzed, of which 158 in patients with CAC = 0. The pooled relative risk ratio was 5.71 (95%-CI: 3.98;8.19) for subjects with CAC > 0. The pooled estimate of adjusted HRs demonstrated increasing, positive associations, with the strongest association for CAC > 400 (HR: 4.88; 95%-CI: 2.44;9.27). CONCLUSIONS: This meta-analysis demonstrated that increased levels of CAC are strongly and independently associated with increased risk for MACE in stable, symptomatic patients with suspected CAD, showing increasing risk with greater CAC scores. Application of CAC scanning as a prediction method could be useful for a considerable number of such patients.

Performance of adenosine "stress-only" perfusion MRI in patients without a history of myocardial infarction: a clinical outcome study.

To assess the diagnostic value of adenosine "stress-only" myocardial perfusion MR for ischemia detection as an indicator for coronary angiography in patients without a prior myocardial infarction and a necessity to exclude ischemia. Adenosine perfusion MRI was performed at 1.5 T in 139 patients with a suspicion of ischemia and no prior myocardial infarction. After 3 min of adenosine infusion a perfusion sequence was started. Patients with a perfusion defect were referred to coronary angiography (CAG). Patients with a normal perfusion were enrolled in follow-up. Fourteen out of 139 patients (10.1%) had a perfusion defect indicative of ischemia. These patients underwent a coronary angiogram, which showed complete agreement with the perfusion images. 125 patients with a normal myocardial perfusion entered follow-up (median 672 days, range 333-1287 days). In the first year of follow-up one Major Adverse Coronary Event (MACE) occurred and one patient had new onset chest pain with a confirmed coronary stenosis. Reaching a negative predictive value for MACE of 99.2% and for any coronary event of 98.4%. At 2 year follow-up no additional MACE occurred. Sensitivity of adenosine perfusion MR for MACE is 93.3% and specificity and positive predictive value are 100%. Adenosine myocardial perfusion MR for the detection of myocardial ischemia in a "stress-only" protocol in patients without prior myocardial infarctions, has a high diagnostic accuracy. This fast examination can play an important role in the evaluation of patients without prior myocardial infarctions and a necessity to exclude ischemia.