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Acute myocardial infarction treated with intravenous streptokinase: 6-year follow-up
J C Nicolau1, S A Garzon, M A Pinto
1Instituto de Moléstias Cardiovasculares, São José do Rio Preto, Brazil.
Insights
This study identified key factors influencing survival after myocardial infarction. Key predictors for reduced survival include reinfarction, anterior infarct location, lower ejection fraction, and previous heart attacks.
Area of Science:
- Cardiology
- Clinical Medicine
- Public Health
Background:
- Myocardial infarction (MI) poses significant short- and long-term mortality risks.
- Identifying prognostic factors in the acute phase is crucial for optimizing patient management and survival.
- Previous studies have explored various predictors, but a comprehensive analysis of factors influencing both 1-year and 6-year survival post-MI is warranted.
Purpose of the Study:
- To investigate variables present during the acute phase of myocardial infarction that impact medium-term (1st year) and long-term (6th year) patient survival.
- To analyze the influence of factors such as left ventricle ejection fraction, reinfarction, previous MI, and treatment strategies on survival outcomes.
- To provide data that can inform clinical decision-making and improve post-MI patient care.
Main Methods:
- Prospective cohort study of 305 patients surviving the acute phase after intravenous streptokinase treatment for MI.
- Analysis of clinical variables including left ventricle ejection fraction, hypotension, CK-MB peak, previous MI, coronary obstruction, reinfarction, sex, treatment, age, and infarct location.
- Survival analysis using the log-rank test to compare survival rates between different patient groups at 1 and 6 years post-MI.
Main Results:
- Overall 1-year survival was 93.8% and 6-year survival was 83.7%.
- Significantly lower 1-year survival was observed in patients with reinfarction (82.6%), anterior infarct location (91.4%), ejection fraction ≤50% (90.6%), and previous MI (80.6%).
- Significantly lower 6-year survival was associated with ejection fraction ≤50% (73.9%), age >65 years (66.4%), and previous MI (60.7%).
Conclusions:
- Reinfarction, anterior infarct location, reduced ejection fraction, and a history of previous MI are critical predictors of decreased short- and long-term survival after acute myocardial infarction.
- Aggressive treatment strategies and maintaining a higher ejection fraction appear to improve long-term survival.
- Early identification and management of these risk factors are essential for improving outcomes in post-MI patients.
Abstract:
Our objective was to investigate variables which, although occurring during the acute period, could influence the medium (1st year) and long-term (6th year) survival of infarcted patients. Of a total of 332 patients treated consecutively and prospectively according to the same protocol which included intravenous streptokinase, 305 survived the hospital phase and represent the study population. Mean patient age was 55.6 +/- 10 years and mean follow-up time was 3.33 years, with 1008.59 patient-years. The clinical course of the group was analyzed according to the following variables: left ventricle ejection fraction, hypotension per/peri streptokinase infusion, CK-MB peak, previous myocardial infarction, number of obstructed coronaries, reinfarction, sex, 'definitive' treatment, residual obstruction, age, pain/streptokinase infusion interval, patency of the 'culprit' coronary and infarct location. Overall, patient survival was 93.8 +/- 1.4% during the 1st year and 83.7 +/- 2.6% at the 6th. The following groups showed significantly different (log-rank) survivals: (a) 1st year: 94.6% for absence and 82.6% for presence of reinfarction (P = 0.0451); 97.9% for inferior and 91.4% for anterior infarct location (P = 0.044); 96.4% for ejection fraction > 50% and 90.6% for ejection fraction < or = 50% (P = 0.0187); 96.5% for angioplasty/surgery and 90.1% for clinical treatment (P = 0.0028); 95.5% for absence and 80.6% for presence of previous infarct (P = 0.0001). (b) 6th year: 88.3% for ejection fraction > 50% and 73.9% for ejection fraction < or = 50% (P = 0.028); 87.4% for < or = 65 and 66.4% for > 65 years (P = 0.0114); 89.6% for aggressive and 76.8% for conservative treatment (P = 0.013); 86.6% for absence and 60.7% for presence of previous infarct (P = 0.0009).