Aims: To identify, without additional investigation, a large group of myocardial infarction patients at low risk who would qualify for early discharge.
Methods: The decision rule was developed in 647 unselected patients with consecutively admitted myocardial infarction, and validated in 825 others. Daily event-rates were calculated for major (death, ventricular fibrillation, recurrent infarction, heart failure, advanced AV-block) and minor (unstable angina and rhythm-abnormalities) cardiac complications.
Results: Patients free from major complications until day 7 (44% of all patients) were found to constitute a very low risk group and thus would qualify for discharge at day 7. Of the 39% of patients with an uncomplicated infarction (low risk) in the validation group, 31% were discharged at day 7, while 8% stayed longer because of non-cardiac co-morbidity, for social reasons or logistic problems. No major adverse event occurred within 7 days after hospital discharge and only 1.8% developed complications within 1 month. The median duration of hospital stay for all in-hospital survivors was 7 days compared to 10 days in the control group.
Conclusion: Prospective application of the early discharge decision rule, based upon simple clinical variables and without the need for additional non-invasive and/or invasive tests, resulted in a significant reduction of hospital stay. The decision rule correctly classified patients into high and low risk groups and appeared feasible and safe. Its efficacy was demonstrated by its ability to identify a large group of post infarction survivors at low risk for complications during follow-up.