Noninvasive detection of coronary vasospastic angina using a double-acquisition coronary CT angiography protocol in the presence and absence of an intravenous nitrate: a pilot study

To evaluate the feasibility of a double-acquisition coronary CT angiography (CCTA) protocol in the presence and absence of an intravenous (IV) vasodilator infusion for detecting vasospastic angina. Twenty patients with a high clinical probability of vasospastic angina were enrolled. All subjects underwent baseline CCTA without a vasodilator in the early morning followed by a catheterized coronary angiography with ergonovine provocation test. Within 3 days, all subjects underwent repeat CCTA during a continuous IV infusion of nitrate. Vasospastic angina as detected by CCTA was defined as significant stenosis (≥50 %) with negative remodelling 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. The CCTA results were compared to the catheterized ergonovine provocation test as the reference standard. Among 20 patients, the catheterized ergonovine provocation test detected vasospasm in 15 patients. The sensitivity, specificity, positive predictive value and negative predictive value of CCTA in a per-patient-based analysis were 73, 100, 100 and 56 %, respectively. Double-acquisition CCTA in the presence and absence of IV infusion of nitrate allows noninvasive detection of vasospastic angina with moderate sensitivity and high specificity. (orig.)