Acetylcholine-Induced Coronary Spasm Patterns

The ACh‐provocation test was performed as described previously in the indication and procedure of the VSA Guideline by the Japanese Circulation Society.^{22 (link)} Coronary spasm was defined as total or subtotal obstruction within the borders of 1 isolated coronary segment as defined by the American Heart Association^{23 (link)} (focal spasm) or severe diffuse vasoconstriction (90% stenosis defined by the American Heart Association^{23 (link)} [76% to 90% narrowing of the luminal diameter]) observed in ≥2 adjacent coronary segments (diffuse spasm) of epicardial coronary arteries associated with transient myocardial ischemia, as evidenced by ischemic ST‐segment changes on the ECG. In the present study, we divided the patients positive for ACh‐provocation test into 2 groups based on the pattern of coronary artery spasm on coronary angiography during ACh‐provocation test: those with focal and those with nonfocal (diffuse) spasm patterns. Figure 1 shows coronary angiographic findings of representative cases of focal and diffuse spasm patterns. Patients who developed ACh‐induced focal spasm with or without diffuse spasm in other coronary segments were included into the focal spasm group (Figure 1A through 1C), whereas patients who had only ACh‐induced diffuse spasm were included in the diffuse spasm group (Figure 1D through 1F). In this study, ischemic ST‐segment changes were defined as ST‐segment elevation (>0.1 mV), ST‐segment depression (>0.1 mV) from baseline level occurring at 60 to 80 ms after J point in at least 2 contiguous leads on the 12‐lead ECG, or appearance of a new negative U wave on the ECG. Multivessel spasm was defined as ACh‐induced spasm of ≥2 major epicardial arteries. Myocardial lactate production was evidenced by comparing serum lactate concentrations at the root of the aorta and coronary sinus, sampled during myocardial ischemia induced by ACh‐provocation.