Purpose. We evaluated if different clinical characteristics are associated to different responses at intracoronary provocative test. In particular, we compared clinical features of patients developing epicardial spasm or microvascular spasm.
Methods. We prospectively enrolled patients undergoing invasive coronary angiography with evidence of non-obstructive coronary arteries and receiving a provocative test with ACh or ergonovine for suspected vasomotor abnormalities. Only patients with a positive response at provocative test were included in the final analysis. Both patients with stable angina and patients presenting with acute coronary syndromes (ACS) were enrolled in our study.
Results. We included 119 patients [mean age 62.7±12.4 years, 57 (47.9%) male] presenting with non-obstructive coronary artery disease and with a positive response at invasive provocative test (68 patients with stable angina and 51 patients with ACS). Of note, patients with epicardial spasm compared with patients with microvascular spasm were more frequently smokers [24 (31.2%) vs 3 (7.1%), p=0.003)], had diffuse coronary atherosclerosis rather than normal coronary arteries [60 (77.9%) vs 20 (47.6%), p=0.003)], and had an ACS as clinical presentation [39 (50.6%) vs 12 (28.6%), p=0.03)]. On the other hand, patients with microvascular spasm presented more frequently diastolic dysfunction compared with patients with epicardial spasm [23 (54.7%) vs 32 (41.6%), p=0.045)].
Conclusions. Coronary vasomotor abnormalities represent an important cause of myocardial ischemia both in patients presenting with stable angina and in patients presenting with ACS. Of importance, our study demonstrated that specific clinical features are associated to different responses to intracoronary provocative test. In particular, epicardial spasm is more frequent in ACS patients, whereas microvascular spasm is more frequent in patients with stable angina and is associated with diastolic dysfunction.