The prognostic value of serum myoglobin in patients with non–ST-segment elevation acute coronary syndromes Results from the TIMI 11B and TACTICS-TIMI 18 studies

AbstractObjectivesThe goal of this study was to define the prognostic value of serum myoglobin in patients with non–ST-elevation acute coronary syndromes (ACS).BackgroundWhile myoglobin is useful for the early diagnosis of myocardial infarction (MI), its role in the early risk-stratification of patients with ACS has not been established.MethodsMyoglobin, creatine kinase-MB subfraction (CK-MB) and troponin I (cTnI) were measured at randomization in 616 patients from the Thrombolysis In Myocardial Ischemia/Infarction (TIMI) 11B study and 1,841 patients from the Treat Angina with Aggrastat and Determine Cost of Therapy with an Invasive or Conservative Therapy-Thrombolysis In Myocardial Ischemia/Infarction (TACTICS-TIMI) 18 study. The risks for death and nonfatal MI through six months of follow-up were compared between patients with and without myoglobin elevation (>110 μg/l) in each study and in a dataset combining all eligible patients from both studies (n = 2,457).ResultsIn a multivariate model adjusting for baseline characteristics, ST changes and CK-MB and cTnI levels, an elevated baseline myoglobin was associated with increased six-month mortality in TIMI 11B (adjusted odds ratio [OR] 2.9 [95% confidence interval {CI} 1.2 to 7.1]), TACTICS-TIMI 18 (adjusted OR 3.0 [95% CI 1.5 to 5.9]) and the combined dataset (adjusted OR 3.0 [95% CI 1.8 to 5.0]). In contrast, there was no significant association between myoglobin elevation and nonfatal MI (combined dataset adjusted OR 1.55, 95% CI 0.9 to 2.6). In TACTICS-TIMI 18, patients with versus those without myoglobin elevation were more likely to have an occluded culprit artery (28% vs. 10%; p < 0.0001) and visible thrombus (49% vs. 34%; p = 0.006) and less likely to have TIMI 3 flow (53% vs. 68%; p = 0.009).ConclusionsA serum concentration of myoglobin above the MI detection threshold (>110 μg/l) is associated with an increased risk of six-month mortality, independent of baseline clinical characteristics, electrocardiographic changes and elevation in CK-MB and cTnI. These findings suggest that myoglobin may be a useful addition to cardiac biomarker panels for early risk-stratification in ACS

Comparison of front-loaded recombinant tissue-type plasminogen activator, anistreplase and combination thrombolytic therapy for acute myocardial infarction: Results of the thrombolysis in myocardial infarction (TIMI) 4 trial

AbstractObjectives. The aim of our study was to determine a superior tbrombolytic regimen from three: anistreplase (APSAC), frontloaded recombinant tissue-type plasminogen activator (rt-PA) or combination thrombolytic therapy.Background. Although thrombolytic therapy has been shown to reduce mortality and morbidity after acute myocardial infarction, it has not been clear whether more aggressive thrombolyticantithrombotic regimens could improve the outcome achieved with standard regimens.Methods. To address this issue, 382 patients with acute myocardial infection were randomized to receive in a double-blind fashion (along with intravenous heparin and aspirin) APSAC, front-loaded rt-PA or a combination of both agents. The primary end point “unsatisfactory outcome” was a composite clinical end point assessed through hospital discharge.Results. Patency of the infarct-related artery (Thrombolysis in Myocardial Infarction [TIMI] grade 2 or 3 flow) at 60 min after the start of thrombolysis was significantly higher in rt-PA-treated patients (77.8% vs. 59.5% for APSAC-treated patients and 59.3% for combination-treated patients [rt-PA vs. APSAC, p = 0.02; rt-PA vs. combination, p = 0.03]). At 90 min, the incidence of both infarct-related artery patency and TIMI grade 3 flow was significantly higher in rt-PA-treated patients (60.2% had TIMI grade 3 flow vs. 42.9% and 44.8% of APSAC- and combination-treated patients, respectively [rt-PA vs. APSAC, p < 0.01; rt-PA vs. combination, p = 0.02]). The incidence of unsatisfactory outcome was 41.3% for rt-PA compared with 49% for APSAC and 53.6% for the combination (rt-PA vs. APSAC, p = 0.19; rt-PA vs. combination, p = 0.06). The mortality rate at 6 weeks was lowest in the rt-PA-treated patients (2.2% vs. 8.8% for APSAC and 7.2% for combination thrombolytic therapy [rt-PA vs. APSAC, p = 0.02; rt-PA vs. combination, p = 0.06]).Conclusions. Front-loaded rt-PA achieved significantly higher rates of early reperfusion and was associated with trends toward better overall clinical benefit and survival than those achieved with a standard thrombolytic agent or combination thrombolytic therapy. These findings support the concept that more rapid reperfusion of the infarct-related artery is associated with improved clinical outcome