Decision support and the appropriate use of fibrinolysis in myocardial infarction

For patients with suspected acute myocardial infarction, decisions about fibrinolytic therapy must account for trade-offs between risks and benefits, which vary according to the clinical characteristics of the patient.

To assess whether use of a decision-support computer program (DSCP) improves the selection of appropriate candidates for fibrinolytic therapy among patients with suspected acute myocardial infarction.

Before-and-after trial at a small rural hospital in Ireland.

DSCP based on a previously published decision-analysis model. With input of patient characteristics (e.g., age, sex, duration of symptoms, findings on electrocardiography) at initial evaluation, the DSCP predicts the likelihood of different outcomes (e.g., mortality, stroke) and life expectancy with and without fibrinolysis.

894 consecutive patients (262 before DSCP was introduced, 632 after) admitted to the coronary care unit with suspected acute myocardial infarction between January 1993 and July 1999.

Proportion of appropriate candidates (ST-segment elevation > 2 mm on electrocardiogram, symptom duration < or = 6 hours) receiving fibrinolysis before and after implementation of DSCP.

In general, patients admitted before and after DSCP implementation had similar clinical characteristics. The preintervention group presented somewhat earlier after the onset of symptoms (5.4 hours for preintervention vs. 7.2 hours for postintervention; P < 0.01) but had fewer confirmed acute myocardial infarctions (32% vs. 38%; P = 0.13). The proportion of appropriate patients receiving fibrinolysis before and after DSCP was nearly identical (66.7% vs. 68.9%; P > 0.2). Patients who received fibrinolysis after implementation of DSCP tended to be older (66.7 years vs. 63.8 years; P = 0.11) and were more likely to be female (36% vs. 26%; P > 0.2) than those who received fibrinolysis before DSCP implementation. The door-to-needle time decreased significantly from 88 minutes to 67 minutes after implementation of DSCP (P < 0.01).

Although overall rates of fibrinolysis did not change after implementation of DSCP, fibrinolytics may have been more appropriately directed toward higher risk patients who may be more likely to benefit from them.