Clinical implications of ST-segment non-resolution after thrombolysis for myocardial infarction

Abstract

Failed reperfusion after thrombolytic therapy for acute myocardial infarction is common and signifies a poor prognosis. We investigated the clinical consequences of non-resolution of the ST segment after thrombolytic therapy for acute ST-elevation myocardial infarction, in 85 consecutive patients admitted to a coronary care unit lacking rapid access to angioplasty. Failed thrombolysis was defined as <50% ST-segment resolution 180 minutes after the start of thrombolytic treatment. Outcomes were measured in terms of in-hospital adverse events, length of hospital stay, and mortality at 6 weeks and 1 year. Thrombolysis was successful, in terms of ST-segment resolution, in 45 patients (53%). After adjustment for other factors, ST resolution was the only independent predictor of an uncomplicated recovery in hospital (odds ratio 6.8, 95% confidence interval 2.3 to 19.9; P<0.001). At 6 weeks and 1 year, overall mortality was lower in the ST resolution group, though these differences became non-significant on multivariate analysis. In patients who survived to hospital discharge, median length of stay was greater in successfully thrombolysed patients (9 days versus 8 days) despite their lower rate of complications. ST-segment resolution is a useful marker of successful thrombolysis and relates to clinical outcome. If assessed routinely it might assist, along with other clinical markers, in the identification of low-risk patients who can be discharged early.