Coronary microvascular disease in patients referred to coronary angiography following coronary computed tomography angiography

BACKGROUND: Ischaemia without obstructive epicardial coronary artery disease (CAD) is common and is often related to coronary microvascular disease (CMD). Previous studies primarily focused on functional assessment in patients with established ischaemia without obstructive epicardial CAD. AIMS: Rb-PET), and health status according to CAD classification. METHODS: Rb-PET and health status at baseline and at 3-month follow-up according to CAD classification (no disease, obstructive epicardial CAD, isolated CMD or combined obstructive epicardial CAD and CMD). RESULTS: Among 561 patients, isolated CMD was diagnosed in 131 patients (prevalence 0.23, 95% confidence interval [CI]: 0.20-0.27). Vessel territories with isolated CMD were characterised by similar perfusion characteristics to non-diseased vessels (mean difference in hyperaemic myocardial blood flow 0.03 [95% CI: -0.13 to 0.06] mL/min/g). Patients with isolated epicardial disease on both patient and vessel levels had reduced stress myocardial blood flow compared to patients without disease. The probability of being angina-free at 3 months tended to be lower for the CMD group (odds ratio [OR] 0.56, 95% CI: 0.31-1.00) and higher for the revascularised epicardial disease group (OR 1.52, 95% CI: 0.94-2.48) compared to the group classified as not diseased. CONCLUSIONS: Rb-PET. (ClinicalTrials.gov: NCT02264717 and NCT04707859).