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[Silent myocardial ischemia in myocardial infarction patients: its prognostic significance]
T Saito1, H Kishida, Y Yamazaki
1First Department of Internal Medicine, Nippon Medical School, Tokyo.
Insights
Silent myocardial ischemia (SMI) significantly predicts adverse cardiac events in patients with prior myocardial infarction. Early revascularization is recommended for SMI patients, regardless of symptoms, to improve outcomes.
Area of Science:
- Cardiology
- Clinical Medicine
- Preventive Cardiology
Background:
- Silent myocardial ischemia (SMI) is a critical concern in patients with established coronary artery disease.
- Understanding the prognostic implications of SMI is vital for guiding patient management.
Purpose of the Study:
- To assess the prognostic and clinical significance of silent myocardial ischemia (SMI) in patients with old myocardial infarction.
- To identify predictors of cardiac events in this patient cohort.
Main Methods:
- 160 patients with old myocardial infarction underwent Holter monitoring, treadmill exercise testing, and coronary angiography.
- Cox's proportional hazard regression and Kaplan-Meier survival analysis were used to identify event predictors.
- A 44-month follow-up period was employed to track cardiac events.
Main Results:
- The overall incidence of cardiac events was 18% over 44 months.
- Silent myocardial ischemia (SMI) was present in 38% of patients and was a significant predictor of unfavorable outcomes.
- Patients with SMI had a higher cardiac event rate (32% vs. 9%, p < 0.05), with reinfarction being the most common event.
Conclusions:
- Silent myocardial ischemia (SMI) is a significant independent predictor of adverse outcomes in patients with old myocardial infarction.
- Lower ejection fraction and maximum ST depression on Holter monitoring predicted cardiac events in SMI patients.
- Early revascularization (percutaneous coronary angioplasty/coronary artery bypass grafting) is recommended for SMI patients, irrespective of anginal symptoms.
Abstract:
To evaluate the prognostic and clinical significance of silent myocardial ischemia (SMI), we examined cardiac events in 160 patients with old myocardial infarction who underwent ambulatory Holter monitoring, treadmill exercise testing and coronary angiography. Using the Cox's proportional hazard regression model and the survival curves with the Kaplan-Meier method, we identified the predictors of cardiac events. The incidence of cardiac events for all the patients during the 44-month follow-up period was 18%. The significant predictors of unfavorable outcomes were severe coronary lesions and SMI. The incidence of SMI was 38%. The cardiac event rate in patients with SMI was higher than in those without SMI (32 vs 9%, p < 0.05). The most frequent cardiac event in patients with SMI was reinfarction, and the significant predictors of cardiac events for these SMI patients were lower ejection fraction and maximum ST depression on Holter monitoring. In conclusion, SMI proved to be a significant predictor of unfavorable outcome in patients with old myocardial infarction. It was, therefore, suggested that revascularization (PTCA/CABG) should be used as early as possible in patients with SMI whether anginal symptoms are present or not.