Mechanisms of nonfatal acute myocardial infarction late after stent implantation: The relative impact of disease progression, stent restenosis, and stent thrombosis

BackgroundThe impact of stent restenosis, stent thrombosis, or progression of disease at another site as responsible mechanisms of acute myocardial infarction (AMI) after stent implantation is not clear.MethodsBy searching our catheterization laboratory database for a 4-year period, 91 cases of nonfatal AMI at least 1 month after stent implantation (32.6% drug-eluting stents) were identified. By detailed comparison of post-AMI with the initial percutaneous coronary intervention angiogram, the mechanism of AMI was analyzed.ResultsAcute myocardial infarction was attributed to disease progression at another site in 42 (46.2%), stent restenosis in 35 (38.4%), and stent thrombosis in 10 (11%) cases. The AMI mechanism could be either stent related or disease progression (nonidentifiable culprit lesion) in 4 cases (4.4%). The median time from percutaneous coronary intervention to AMI was 27, 19, and 9 months for disease progression at another site, restenosis, and stent thrombosis group, respectively (P = .03). ST-elevation myocardial infarction occurred in 38.1% of the disease progression, in 20% of the restenosis, and in 60% of the stent thrombosis cases (P = .046).ConclusionsIn a “real world” population, late after stent implantation, a patient has an almost equal probability to have suffered a nonfatal AMI from either stent restenosis/thrombosis or disease progression at another site. Continuous research efforts are necessary to equally address both stent therapy and disease progression.