Background: Coronary spasm is known to have two morphologic types on coronary angiography: focal and diffuse spasms. Several reports have demonstrated these coronary vasospasm subtypes to be associated with the severity or prognosis of coronary spasm in patients with vasospastic angina (VSA). It is unclear whether the intra-coronary pressure varies according to these two subtypes during a coronary spasm.
Purpose: Therefore, we investigated this relationship using a pressure wire during spasm provocation test (SPT) in patients with VSA.
Methods: Eighty-seven patients with VSA (mean age 67 years; 50 male and 37 female) underwent an acetylcholine (ACh)-induced SPT, wherein a pressure wire was advanced into the distal portion of the right coronary artery (RCA) and the left anterior descending coronary artery (LAD), respectively, and the ratio of intra-coronary pressure to aortic pressure (Pd/Pa) was continuously monitored. Coronary spasm was defined as >90% narrowing of coronary artery in response to an ACh infusion, accompanied by usual chest symptoms and/or ischaemic changes on ECG. Focal spasm was defined as total or subtotal spasm within one segment of the American Heart Association (AHA) classification, and diffuse spasm was defined as >90% spasm with two or more segments of the AHA classification.
Results: Among 87 patients, coronary spasm was induced in 58 RCA vessels and 74 LAD vessels. In these 132 spastic segments, diffuse or focal spasm was detected in 102 (77%) and 30 (23%) vessels, respectively. The baseline Pd/Pa was similar in both groups (diffuse: 0.96±0.05, focal: 0.95±0.05, NS); however, the minimal Pd/Pa during coronary spasm was lower in vessels with focal spasm (0.67±0.03) than in those with diffuse spasm (0.76±0.01, p<0.01).
Conclusions: These findings suggest that focal spasm may be more severe than diffuse spasm, judging from intra-coronary pressure during a coronary spasm. If a focal spasm is present, stronger medical interventions may be necessary.