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Role of coronary interventional procedures in improved postinfarction survival in the 1990s
1Department of Medicine, University of Western Australia, Western Perth, Australia.
Insights
Improved survival for acute myocardial infarction (AMI) patients occurred between 1990-1998. However, this progress in hospital survival was not linked to increased use of percutaneous coronary interventions.
Area of Science:
- Cardiology
- Clinical Medicine
- Public Health
Background:
- Acute myocardial infarction (AMI) survival rates have seen improvements.
- The role of percutaneous coronary interventions (PCI) in these improvements is debated.
Purpose of the Study:
- To investigate the contribution of increased PCI use to improved hospital survival in AMI patients.
- To analyze trends in patient risk, procedural interventions, and outcomes over a 9-year period.
Main Methods:
- Retrospective analysis of 2,628 patients with AMI (ICD code 410) admitted between 1990 and 1998.
- Comparison of outcomes across three 3-year periods (triennia) within the study timeframe.
- Analysis of risk factors, PCI utilization, and in-hospital mortality rates.
Main Results:
- Hospital mortality for AMI decreased by 33% from 8.7% in earlier triennia to 5.8% in the third triennium (1996-1998).
- This reduction in mortality was not attributable to shorter hospital stays or treatment of lower-risk patients, as risk scores increased.
- Despite a doubling of PCI use in the third triennium, most procedures were performed on low-risk patients (1% mortality risk).
Conclusions:
- Significant improvements in early case fatality for AMI patients were observed between 1990 and 1998.
- The increased utilization of in-hospital PCI did not drive these survival improvements.
- PCI was predominantly used in low-risk AMI patients, suggesting other factors contributed to the observed survival gains.
Abstract:
The contribution of increased use of same-admission percutaneous coronary interventional procedures to recent improvements in hospital survival of patients with acute myocardial infarction (AMI) remains unclear. Patients with International Classification of Diseases codes for AMI (code 410), who were admitted to the emergency coronary care unit and underwent an initial episode of treatment, were studied over the 9-year period 1990 to 1998 (n = 2,628). Three triennia between 1990 and 1998 were compared. Trends in risk, the use of procedures, and hospital outcomes were analyzed. Hospital mortality was 33% lower (p <0.02) in the third triennium (5.8%) than in the earlier 2 triennia (8.7%), equivalent to an absolute reduction of 29 hospital deaths/1,000 patients treated. The lower hospital mortality was not due to: (1) shorter hospital stays (reduction in mortality was primarily in the first 3 hospital days), (2) treatment of lower risk subjects (a risk score based on age, gender, and presence of diabetes increased between the first and third triennia), or (3) use of in-hospital interventional procedures (although the use of percutaneous coronary intervention more than doubled in the third triennium, most procedures were performed in patients with a 1% risk of hospital death). We conclude from this study that there has been a substantial improvement over a 9-year period in early case fatality after AMI, but that this cannot be attributed to the increased use of in-hospital coronary interventions, which were largely performed on low-risk patients.