Role of Dual-Acquisition Noninvasive Cardiac CT Imaging for the Detection of Vasospastic Angina

Background: Vasospastic angina (VSA) is characterized by chest pain at rest with transient ischemic electrocardiographic changes in the ST segment, and a prompt response to nitrates. Vasospastic angina is among the most frequent of the coronary artery diseases in Asia, and coronary computed tomography angiography (CCTA) may become available as a non-invasive diagnosis method. Methods: We prospectively enrolled 100 patients with suspected vasospastic angina at two centers from 2018 to 2020. All patients underwent baseline CCTA without a vasodilator in the early morning followed by catheterized coronary angiography and spasm testing. CCTA with intravenous infusion of nitrate (IV) was repeated within 2 weeks of baseline CCTA. Vasospastic angina as detected by CCTA was defined as significant stenosis (≥50%) with negative remodeling without definite plaques or diffuse small diameter (<2 mm) of a major coronary artery with a beaded appearance on baseline CT that completely dilated on IV nitrate CT. We analyzed diagnostic performance of dual-acquisition CCTA for the detection of vasospastic angina. Results: The patients were categorized into three groups according to their provocation test result (negative, n = 36; probable positive, n = 18; positive, n = 31). The diagnostic accuracy in terms of CCTA per patient had a sensitivity of 55% (95% CI, 40–69), specificity of 89% (95% CI, 74–97), positive predictive value (PPV) of 87% (95% CI, 72–95), and negative predictive value (NPV) of 59% (95% CI, 51–67). Conclusions: Dual-acquisition CCTA can support the non-invasive detection of vasospastic angina with relatively good specificity and PPV. CCTA was helpful for non-invasive screening of variant angina.