Pharmacoepidemiology of Bleeding Events after Use of R-Alteplase or Streptokinase in Acute Myocardial Infarction

Abstract

OBJECTIVE: To determine in nonresearch, general medical practice conditions the comparative incidence and types of bleeding complications after the use of streptokinase (SK) and r-alteplase (recombinant tissue plasminogen activator, rt-PA) to treat acute myocardial infarction (AMI). DESIGN: Retrospective medical record review of concurrently treated patients (96-hour observation posttreatment) in 32 participating hospitals in the US. MAIN OUTCOME MEASURES: The medical record description of all bleeding events regarding the body site affected, changes in hemoglobin concentrations, blood products administered, and clinical outcome (permanent sequelae or death). Bleeding severity was determined by defined criteria. CONTROL DATA: Comorbidity and concomitant medications (e.g., aspirin, heparin, warfarin) likely to predispose or contribute to bleeding events were analyzed. DATA ANALYSIS: Logistic regression analysis. RESULTS: Data from 419 patients who received rt-PA and 207 who received SK were evaluated. In the 96-hour period after initiation of thrombolytic therapy, 30.5 and 31.9 percent of rt-PA and SK patients, respectively, experienced one or more bleeding events (crude risk ratio [CRR] = 1.04; 95 percent confidence interval [CI] 0.91–1.14; p=0.73). In the first 24-hour period, 21.5 percent of rt-PA and 15.9 percent of SK patients experienced bleeding events (CRR = 0.74; 95 percent CI 0.42–1.15; p=0.08). The leading types of bleeding and percents of all patients affected were: Perivascular access site (18.4 percent), gastrointestinal (6.4 percent), skin/soft tissue/muscle (5.0 percent), urinary (3.4 percent), pulmonary (2.2 percent), systemic (1.9 percent), and oral (1.4 percent). Intracranial bleeding occurred in 4 rt-PA and 2 SK patients; 4 of these patients died. Events deemed clinically significant occurred in 15 rt-PA and 9 SK patients (3.8 percent of all patients). Ten patients likely died from these events, 6 within the first 24 hours. Three rt-PA patients and 1 who received SK (0.6 percent) died of cerebrovascular events within the first 24 hours. After controlling for demographic factors and therapeutic variables, using logistic regression analyses, no thrombolytic-related differences were found in the incidence or severity of bleeding following use of the two thrombolytics. CONCLUSIONS: These clinical data do not support a theoretical advantage of rt-PA to cause less bleeding propensity than SK.