The Relationship Between Absence Coronary Artery Calcification and Myocardial Perfusion Single Photon Emission Computed Tomography

Diagnostic Accuracy of Computed Tomography Coronary Angiography in Patients Presenting with Heart Failure of Unknown Etiology in the Middle East

Objectives:

The purpose of this study is to assess the diagnostic performance of coronary artery calcium score (CACS), computed tomography coronary angiography (CTCA), and the prevalence of coronary artery disease (CAD) as etiology of heart failure (HF) in the Middle Eastern population.

Background:

CTCA has several advantages compared to invasive coronary angiography (ICA). However, studies on the diagnostic accuracy of CTCA and CACS in detecting the prevalence of CAD in patients with newly diagnosed HF are lacking in the Middle East.

Methods:

This study included 204 patients with symptoms of HF and ejection fraction (EF) of <50% by echocardiography who underwent CTCA for diagnosis of CAD within 3 months. The exclusion criteria were defined as patients with a history of CAD, percutaneous coronary intervention, or coronary artery bypass grafting. All patients with obstructive CAD based on CTCA were referred for ICA. In addition, 30 patients with normal CTCA also underwent ICA for verification.

Results:

The mean age was 48 ± 13 years, 69% (n = 141) were male and 31% (n = 73) were female, mean left ventricular EF was 31% ± 9%, and mean CACS was 58 ± 120. Based on the CTCA results, 169 patients had normal or nonobstructive CAD, whereas 35 patients had obstructive CAD. ICA was performed in all 35 patients with obstructive CAD; 30 of them were confirmed as having abnormal ICA, and only 5 had nonobstructive CAD. In addition, 30 patients with normal CTCA underwent ICA testing and were confirmed as having normal ICA. The CTCA had 100% sensitivity, 84% specificity, 86% positive predictive value, and 100% negative predictive value. Of the total population, 30 (15%) who were documented as having obstructive CAD were classified as CAD HF based on ICA. The remaining 174 (85%) patients were classified as having no CAD HF based on normal CTCA and/or ICA. The prevalence of CAD HF based on ICA was 15%. There was a strong correlation between CACS and both CTCA and ICA, with P = 0.001 and 0.0048, respectively.

Conclusion:

In patients with newly diagnosed HF, CACS and CTCA had a 100% sensitivity and negative value as well as overall excellent diagnostic accuracy. CACS = 0 excluded CAD as the etiology of HF with correlation between CACS groups and both CTCA and ICA. The prevalence of CAD as etiology of HF in the study population was 15%.

Benefits of adding coronary calcium score scan to stress myocardial perfusion positron emission tomography imaging

There have been little and conflicting data regarding the relationship between coronary artery calcification score (CACS) and myocardial ischemia on positron emission tomography myocardial perfusion imaging (PET MPI). The aims of this study were to investigate the relationship between myocardial ischemia on PET MPI and CACS, the frequency and severity of CACS in patients with normal PET MPI, and to determine the optimal CACS cutoff point for abnormal PET. This retrospective study included 363 patients who underwent same-setting stress PET perfusion imaging and CACS scan because of clinically suspected coronary artery disease (CAD). Fifty-five (55%) of the 363 patients had abnormal PET perfusion. There was an association between sex, diabetes mellitus (DM), smoking, and CACS and PET perfusion abnormities with P = 0.003, 0.05, 0.005, and 0.001, respectively. However, there was no association between PET perfusion abnormalities with age, body mass index, hypertension, and hypercholesterolemia. There was association between CACS and age, sex, and DM with P = 0.000, 0.014, and 0.052, respectively, and stepwise increase in the frequency of myocardial ischemia and CACS groups. Receiver-operating characteristic analysis showed that a CACS ≥304 is the optimal cutoff for predicting perfusion abnormalities with sensitivity of 64% and specificity of 69%. In conclusion, the frequency of CAC in patients with normal PET MPI is 49%, it is highly recommended to combine CACS with PET MPI in patients without a history of CAD. PET MPI identifies myocardial ischemia and defines the need for coronary revascularization, but CAC reflects the anatomic burden of coronary atherosclerosis. Combining CACS to PET MPI allows better risk stratification and identifies high-risk patients with PET, and it may change future follow-up recommendations. CACS scan is readily available and easily acquired with modern PET-computed tomography (CT) and single-photon emission CT (SPECT)-CT with modest radiation exposure.