Coronary
spasm is an established cause for
angina pectoris. Ethnic differences have been suggested among Asian compared to Caucasian patients regarding prevalence, gender distribution, and angiographic patterns of coronary
spasm. The aim of this study was to compare contemporary German and Japanese patients with coronary
spasm. Between 2011 and 2015, 149 patients with resting angina and unobstructed coronary arteries with
acetylcholine-induced epicardial
spasm were enrolled in Stuttgart, Germany (n = 69) and Sendai, Japan (n = 80). All patients underwent intracoronary
acetylcholine testing according to a standardized protocol. Comprehensive analysis included type of
spasm (focal/diffuse), dose of
acetylcholine leading to
spasm, and frequency of multivessel
spasm. Patients in this study were 61 ± 11 years old, predominantly female (54%), and had normal left ventricular ejection fraction (73 ± 9%). Diffuse
spasm was the most prevalent type of
spasm (85%) whereas focal
spasm was found in the remaining 15% of patients. 31% of patients had multivessel
spasm. Comparing the German with the Japanese patients, distribution of
spasm type (focal/diffuse, p = 0.19) and frequency of multivessel
spasm (p = 0.22) were comparable. Moreover, when Japanese patients were compared with German patients and diffuse
spasm with focal
spasm patients, respectively, no significant differences were observed regarding the
acetylcholine dose required to induce
spasm (p = 0.078 and p = 0.46, respectively). In conclusion, diffuse epicardial coronary
spasm is the most frequent finding among German and Japanese patients with resting angina, unobstructed coronary arteries, and epicardial
spasm on
acetylcholine testing. Japanese and German patients share several similarities including comparable types of
spasm and frequency of multivessel
spasm.