High incidence of provoked coronary spasm in the presence of a stent after myocardial infarction: therapeutic and prognostic implications.

Objective: Coronary spasm is implicated in the pathogenesis of acute coronary syndromes including acute myocardial infarction (AMI). Stent implantation in the primary percutaneous coronary intervention is the first choice of treatment for patients with AMI. However, the relationship between coronary spasm and stent implantation after AMI and its clinical implications remain unknown. We examined the incidence and clinical implications of provoked coronary spasm after stent implantation in patients with AMI.

Methods: Fifty-seven patients (43 men and 14 women with a mean age of 65.1±12.5 years) with ST elevation AMI who had undergone a stent implantation were the participants of this study. They underwent a provocation test for coronary spasm by intracoronary injection of acetylcholine 2-5 weeks after the attack. The patients with provoked spasms were given calcium channel blockers, and all the participants of the study were followed up for an average of 35.0±26.9 months.

Results: Coronary spasm was induced in 40 (70.2%) and multivessel spasm in 17 (29.8%) of the 57 patients. Spasms occurred in 31 (55.4%) of the infarct-related arteries (IRAs) and 33 (30.6%) of the non-IRAs. There was no significant difference (χ=1.01, P=0.314) in the major cardiac events between the spasm group and nonspasm group during the follow-up.

Conclusions: Coronary spasm was provoked with a high frequency in both the IRAs and non-IRAs after stent implantation in patients with AMI. Calcium channel blockers may be useful to improve the prognosis in patients with AMI after stent implantation by suppressing coronary spasm.