Table 2.

Baseline characteristics of included studies

Study	Year	Design	Participants	Total	Aspirin	Without aspirin	Dosage of aspirin (mg)	MACE definition	MACE	Myocardial infarction	Cardiac death	All cause death	Follow-up
Kim12	2013	Retrospective analysis	Vasospastic angina (stenosis ≤70%)	240	96	144	100	Readmission rate associated with recurrent angina, cardiac death, percutaneous coronary intervention	20 (20.8) vs 29 (20.1)	/	1 (1.0) vs 1 (0.7)	/	1 year
Ishii14	2016	Retrospective analysis, propensity score matched analysis	Vasospastic angina (stenosis ≤50%)	224	112	112	81–100	Cardiac death, non-fatal acute myocardial infarction and unstable angina	4 (3.6) vs 6 (5.4)	0 vs 0	2 (1.8) vs 0 (0)	/	1 year
Lim13	2016	Retrospective analysis, propensity score matched analysis	Coronary artery spasm (stenosis ≤50%)	721	434	287	100	Cardiac death, acute myocardial infarction, revascularisation or rehospitalisation due to recurrent angina	100 (23.0) vs 34 (11.8)	9 (2.1) vs 2 (0.7)	4 (0.9) vs 3 (1.0), p=0.5	10 (2.2) vs 9 (1.5)	5 year
Lee11	2018	Retrospective study, propensity score-matched analysis	Coronary artery spasm (stenosis ≤50%)	154	77	77	100	Chest pain recurrence, myocardial infarction and cardiac death	9 (11.7) vs 33 (42.9)	2 (3) vs 13 (17)	0 vs 0	0 vs 0	4 year
Cho15	2019	Prospective multicentre cohort	Coronary artery spasm (stenosis ≤50%)	1652	641	1011	100	All cause death, acute coronary syndrome and symptomatic arrhythmia	29 (4.5) vs 44 (4.4)	/	/	3 (0.5) vs 7 (0.7)	3 year
Mori16	2020	Retrospective study, propensity score-matched analysis	Coronary artery spasm (stenosis ≤50%)	670	335	335	Aspirin 100 and P2Y12 inhibitors.	Cardiac death, non-fatal myocardial infarction, hospitalisation due to unstable angina pectoris and appropriate ICD shock	19 (5.7) vs 12 (3.6)	1 (0.3) vs 2 (0.6)	2 (0.6) vs 0 (0.0)	2 (0.6) vs 6 (1.8)	32 months

ICD, implantable cardioverter defibrillator; MACE, major cardiovascular adverse events.