Examination of the microcirculation damage in smokers versus nonsmokers with vasospastic angina pectoris

Endothelial dysfunction is considered one of the mechanisms underlying vasospastic angina pectoris (VSA). It is also known that smokers have abnormalities in endothelial dysfunction. Although smoking is a major risk factor for coronary artery disease, microvascular abnormalities have not been well shown. We investigated clinical characteristics and coronary reactivity with adenosine triphosphate in smokers with VSA. Twenty-two consecutive patients whose coronary spasm was documented in the left anterior descending (LAD) coronary artery with acetylcholine were enrolled. Coronary blood flow responses were also evaluated by intracoronary Doppler flow velocity recordings in the LAD coronary artery. Average peak velocities (APVs) were measured at baseline and intracoronary administration of adenosine triphosphate (50 microg) in 11 smokers (age 60+/-9 years; 8 men) and 11 nonsmokers (age 61+/-10 years, 5 men). Coronary flow reserve (CFR) was calculated by the ratio of baseline to hyperemic APV. Multivessel spasm was demonstrated in 6 smokers and only 2 nonsmokers (p<0.05). APV at rest in smokers (13.4+/-3.0 cm/s) was similar to that in nonsmokers (13.5+/-2.9 cm/s). However, CFR in smokers (2.6+/-0.7) was significantly lower than in nonsmokers (3.4+/-0.8; p<0.05). In conclusion, multivessel spasm was demonstrated in smokers in clinical settings, and microcirculation damage is prominent in smokers with VSA.