For example, the HERO-2 (Hirulog and Early Reperfusion or Occlusion) trial demonstrated that patients with new or presumed new LBBB had a lower incidence of enzymatically confirmed AMI (80.7% vs. 88.7%, p = 0.006) and lower 30-day mortality (16% vs. 22.7%, p = 0.027) than matched STEMI controls. Differences were observed, however, between LBBB patients with and without Sgarbossa ST-segment concordance criteria: those without concordance had a lower adjusted risk of 30-day mortality compared with those with STEMI (odds ratio: 0.52, 95% CI: 0.33 to 0.80), whereas those meeting concordance criteria had a similar risk (odds ratio: 1.37, 95% CI: 0.78 to 2.47) (22). Similarly, in the ASSENT (Assessment GSK 126 of the Safety and Efficacy of a New Thrombolytic) -2 and -3 trials, 37.5% of LBBB versus 15.6% of STEMI patients (p < 0.001) did not have AMI enzymatically confirmed, and mortality was found to differ between patients with and without Sgarbossa concordance. In this analysis, the adjusted relative risk of mortality at 1 year among patients with LBBB and Sgarbossa concordance (score Cell Cycle inhibitor ��3) compared with STEMI was 3.8 (95% CI: 2.17 to 6.78); however, those with LBBB but without ST-segment concordance had a similar risk of 1-year mortality compared with STEMI patients (relative risk: 0.91, 95% CI: 0.47 to 1.77) (23). It should be noted that enrollment in these trials required a high clinical suspicion for AMI, and nevertheless, a substantially higher proportion of LBBB patients did not have AMI confirmed, especially among those without concordant ECG changes. Taken together, these data suggest that (1) patients with LBBB have heterogeneous outcomes with fibrinolytic therapy in part because of the significant variability in AMI incidence among this group and (2) Sgarbossa concordance on ECG may identify a high-risk population with similar (or worse) outcomes compared with STEMI. More contemporary trials comparing the use of primary PCI with fibrinolysis have not provided much additional information regarding the benefit of urgent reperfusion strategies in patients with LBBB. Although the clinical Cyclopamine nmr superiority of primary PCI over fibrinolysis has been established, there are limited randomized trial data comparing the 2 therapies in patients with LBBB. Only 7 of the 23 trials reported in the meta-analysis by Keeley et al. (24) included patients with LBBB; efficacy or safety outcomes in patient subgroups with LBBB have not been reported from these trials, and the largest trial to date specifically excluded such patients (25). Thus, randomized clinical trial data establishing a clear benefit of urgent reperfusion therapy in patients with LBBB in the modern era are lacking.
Captcha Challenge