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Acute myocardial infarction--a late complication of intracoronary stent placement
H D Danenberg1, C Lotan, Y Hasin
1Department of Cardiology, Hadassah University Hospital, Jerusalem, Israel.
Insights
Myocardial infarction (MI) rarely occurs after coronary stent implantation, but when it does, it is often due to stent occlusion. Hypertension and strenuous exercise may increase the risk of this serious complication.
Area of Science:
- Cardiology
- Interventional Cardiology
- Biomedical Engineering
Background:
- Myocardial infarction (MI) as an initial presentation of postangioplasty restenosis is rare.
- Fibroproliferative restenotic lesions are considered less prone to plaque rupture than native atherosclerotic lesions.
Purpose of the Study:
- To investigate if intracoronary stent implantation influences the occurrence of MI as a complication.
- To evaluate the incidence and characteristics of MI following coronary stenting.
Main Methods:
- Retrospective review of 994 patients undergoing angioplasty with intracoronary stent implantation.
- Analysis of MI occurrence, timing, and associated factors post-stenting.
Main Results:
- Eight patients (0.8%) experienced MI due to stent occlusion more than 30 days post-stenting (range: 35-398 days).
- MI occurred in hypertensive males aged 33-83; two cases followed strenuous exercise.
- Angiography showed stent occlusion/stenosis with intimal dissection in six patients.
Conclusions:
- MI is a rare late complication of successful stent implantation, occurring in 0.8% of patients.
- The interface between the stent and the artery may be vulnerable to stress, leading to rupture and dissection.
- Hypertension and strenuous exercise might elevate stress, increasing the risk of intimal rupture and MI.
Background:
Myocardial infarction (MI) as the first indication of postangioplasty restenosis is extremely rare, and it has been speculated that the fibroproliferative restenotic lesion is less likely to undergo plaque rupture than the lipid-laden native atherosclerotic lesion.
Hypothesis:
The present study was designed to examine whether intracoronary stent implantation affects this course.
Methods:
In all, 994 consecutive patients who underwent angioplasty and intracoronary stent implantation in our hospital were reviewed retrospectively for the occurrence of MI.
Results:
Eight patients (0.8%), all male and hypertensive, aged 33-83 years, presented with an MI due to stent occlusion more than 30 days following stenting (range: 35-398 days). In two patients, MI occurred 3 and 5 h, respectively, following completion of a maximal high-level exercise test that was negative for ischemia. Angiography revealed complete occlusion or significant stenosis of the stent in all eight patients, with an obvious intimal dissection in either edge of the stent in six patients. Except for gender and hypertension, no correlation was found with other risk factors, vessel involved, initial angiographic results, or with stent design, diameter, or length.
Conclusions:
Myocardial infarction as a late complication of successful stent implantation occurred in 0.8% of our patients. This is only the lower bound of the estimated frequency for such an event. We hypothesize that the transition point between the relatively fixed stent and the normal artery is exposed to high deformation stress which makes it vulnerable to rupture and dissection. Strenuous exercise and hypertension may increase the deformation stress and the risk of intimal rupture.