Coronary computed tomography angiography, ECG stress test and nuclear imaging as sources of false-positive results in the detection of coronary artery disease

Prevalence of Coronary Microvascular Disease and Coronary Vasospasm in Patients With Nonobstructive Coronary Artery Disease: Systematic Review and Meta-Analysis

Background

A relevant proportion of patients with suspected coronary artery disease undergo invasive coronary angiography showing normal or nonobstructive coronary arteries. However, the prevalence of coronary microvascular disease (CMD) and coronary spasm in patients with nonobstructive coronary artery disease remains to be determined. The objective of this study was to determine the prevalence of coronary CMD and coronary vasospastic angina in patients with no obstructive coronary artery disease.

Methods and Results

A systematic review and meta‐analysis of studies assessing the prevalence of CMD and vasospastic angina in patients with no obstructive coronary artery disease was performed. Random‐effects models were used to determine the prevalence of these 2 disease entities. Fifty‐six studies comprising 14 427 patients were included. The pooled prevalence of CMD was 0.41 (95% CI, 0.36–0.47), epicardial vasospasm 0.40 (95% CI, 0.34–0.46) and microvascular spasm 24% (95% CI, 0.21–0.28). The prevalence of combined CMD and vasospastic angina was 0.23 (95% CI, 0.17–0.31). Female patients had a higher risk of presenting with CMD compared with male patients (risk ratio, 1.45 [95% CI, 1.11–1.90]). CMD prevalence was similar when assessed using noninvasive or invasive diagnostic methods.

Conclusions

In patients with no obstructive coronary artery disease, approximately half of the cases were reported to have CMD and/or coronary spasm. CMD was more prevalent among female patients. Greater awareness among physicians of ischemia with no obstructive coronary arteries is urgently needed for accurate diagnosis and patient‐tailored management.

Factors for heterogeneous outcomes of angina and myocardial ischemia without obstructive coronary atherosclerosis

BACKGROUND AND OBJECTIVES

The absence of obstructive coronary artery disease (CAD) in patients with angina is common, but its prognosis is debated. We investigated outcomes of such patients to identify predictors of cardiovascular events.

METHODS

We selected 1014 patients with angina, evidence of myocardial ischemia at the electrocardiogram (ECG) exercise test or imaging stress tests, and nonobstructive CAD (absence of lumen diameter reduction ≥50%) at coronary angiography between 1999 and 2015. Note that, 1905 age- and risk factors-matched asymptomatic subjects served as "real-world" comparators. The primary endpoint was the occurrence of all-cause death or myocardial infarction.

RESULTS

At 6-years median follow-up (interquartile range, 3-9 years), the primary endpoint occurred in 53 patients (5.5%, 0.92/100 person-years). Besides similar event rates compared with asymptomatic subjects (hazard ratio [HR] 0.85, 95% confidence interval [CI] 0.62-1.15, p = 0.28), the index population showed a very heterogeneous prognosis. Patients with nonobstructive CAD (HR 1.85, 95% CI 1.02-3.37, p = 0.04, compared with "normal" coronary arteries) and ischemia at imaging tests (HR 2.11, 95% CI 1.07-4.14, p = 0.03, compared with ischemia detected only at the ECG exercise test) were at higher risk and those with both these components showing even >10-fold event rates as compared with the absence of both. Three-hundred and twenty-five patients (34%) continued to experience angina, 69 (7.2%) underwent repeat coronary angiography, and 14 (1.5%) had consequent coronary revascularization for atherosclerosis progression.

CONCLUSION

Apart from the impaired quality of life, angina without obstructive CAD has an overall benign but very heterogeneous prognosis. Nonobstructive CAD and myocardial ischemia at imaging tests both confer a higher risk.

Diagnostic Value of Single-Photon Emission Tomography Stress Test in Patients With Suspected Coronary Artery Disease in Saudi Arabia

Background

Invasive coronary angiography (ICA) is the gold standard procedure for the diagnosis of coronary artery disease (CAD). ICA allows for clear visualization of the coronary arterial blood flow. Single-photon emission computed tomography (SPECT) is currently in widespread use to non-invasively evaluate patients known or suspected of coronary artery disease (CAD). This study aimed to examine the association between (SPECT) stress test and elective ICA in terms of diagnostic value in patients suspected of coronary artery disease at the King Faisal Cardiac Center (KFCC), Jeddah, Saudi Arabia.

Methods

This study is a retrospective diagnostic validation study using a consecutive sampling technique to select the study sample at KFCC. The study included all patients who presented with chest pain that were investigated with either exercise or pharmacologic myocardial perfusion SPECT study followed by elective ICA within six months from January 2015 to January 2020.

Results

A total of 207 patients met the inclusion criteria, where 43% (n = 90) of patients were females and 57% (n = 117) were males; 68% (n = 141) of the patients had both test results concordant (both SPECT and ICA results were in agreement). In 32% of the patients (n = 66), there was a discordant result (discrepant result between SPECT and ICA). SPECT had a sensitivity of 92.4% and a specificity of 26.3%. SPECT had a negative predictive value of 0.68 and a positive predictive value of 0.66 compared to ICA. There was a low degree of reliability between SPECT and ICA.

Conclusion

Reliability between the SPECT and ICA in exclusion of significant CAD is high. The rate of false-positive tests was high while the accuracy of SPECT in detecting CAD in patients with diabetes and hypertension was high. The overall reliability of SPECT to ICA in the Saudi population was low.