Abstract

Cardiogenic shock is a serious complication of a ST-segment elevation myocardial infarction (STEMI). We compared short- and long-term mortality among (1) STEMI patients with and without cardiogenic shock and (2) STEMI patients with cardiogenic shock with and without the use of an intra-aortic balloon pump (IABP). From January 1, 2002 to December 31, 2010, all patients presenting with STEMI and treated with primary percutaneous coronary intervention (PCI) were identified. The hazard ratio (HR) for death was estimated using a Cox regression model, controlling for potential confounding. The study cohort consisted of 4293 STEMI patients: 286 (6.7%) with and 4007 (93.3%) without cardiogenic shock. Compared with patients without cardiogenic shock, patients with cardiogenic shock were older, and more likely to have diabetes mellitus, multi-vessel disease, anterior myocardial infarction (MI) or bundle-branch block MI and a reduced creatinine clearance. Among patients with cardiogenic shock vs. without shock, 30-day cumulative mortality was 57.3% vs. 4.5% (p < 0.001), one-year cumulative mortality was 60.7% vs. 8.2% (p < 0.001) and five-year mortality was 65.0% vs. 18.9% (p < 0.001). STEMI with cardiogenic shock was associated with higher 30-day mortality (adjusted HR = 12.89 [95% CI: 9.72–16.66]), 1-year mortality (adjusted HR = 8.83 [95% CI: 7.06–11.05]) and five-year mortality (adjusted HR = 6.39 [95% CI: 5.22–7.80]). IABP was used in 71 (25%) patients with cardiogenic shock and was associated with improved 30-day outcome (adjusted HR = 0.48 [95% CI: 0.28–0.83]). Patients with STEMI and cardiogenic shock had substantial short- and long-term mortality that may be improved with IABP implantation. More studies on use of IABP in such patients are warranted.

Abstract

Reperfusion of ischemic myocardium is crucial for salvaging myocardial cells from ischemic cell death. However, reperfusion itself induces various deleterious effects on the ischemic myocardium. These effects, known collectively as reperfusion injury, comprise stunned myocardium, reperfusion-induced arrhythmia, microvascular reperfusion injury, and lethal reperfusion injury. No approach has proven successful in preventing any of these injuries in the clinical setting. My colleagues and I recently proposed a new postconditioning protocol, postconditioning with lactate-enriched blood (PCLeB), for the prevention of reperfusion injury. This new approach consists of intermittent reperfusion and timely coronary injections of lactated Ringers solution, aiming to achieve controlled reperfusion with cellular oxygenation and minimal lactate washout from the cells. This approach appeared to be effective in preventing all types of reperfusion injury in patients with ST-segment elevation myocardial infarction (STEMI), and we have already reported excellent in-hospital outcomes of patients with STEMI treated using PCLeB. In this review article, I discuss a possible mechanism of reperfusion injury, which we believe to be valid and which we targeted using this new approach, and I report how the approach worked in preventing each type of reperfusion injury.

Abstract

Accessibility of primary percutaneous coronary intervention (PCI) in patients with ST-segment elevation myocardial infarction (STEMI) in primary care settings is limited. Referring patients to PCI-capable hospitals might increase cardiac events. Hence, fibrinolytic injection before referring patients to PCI-capable settings decreases cardiac events, however, the effect of fibrinolytic injection before the referral has not been systematically evaluated. This study aimed to systematically review the effect of fibrinolytic injection before referring patients with STEMI to PCI-capable settings. A systematic search with Embase, Cochrane CENTRAL, Google scholar, and PubMed was conducted. Studies conducted in patients with STEMI presented to non PCI-capable settings and compared fibrinolytic injection with no injection before referring patients to PCI-capable settings were included. The primary outcome was the composite outcomes of major adverse cardiac events (MACEs) at 30 days. Meta-analyses were performed using random-effect model. Of 912 articles, three RCTs and three non-RCTs were included. Based on RCTs, fibrinolytic injection before the referral has failed to decrease MACEs compared to non-fibrinolytic injection [relative risk (RR) 1.18, 95% confidence interval (CI), 0.89–1.57, p = 0.237]. Fibrinolytic injection has also failed to decrease mortality, re-infarction, and ischemic stroke. On the other hand, fibrinolytic injection was associated with a higher risk of major bleeding. In non PCI-capable settings, fibrinolytic injection before referring patients with STEMI to PCI-capable settings has no clinical benefit but could increase risk of major bleeding. Clinicians might more carefully consider whether fibrinolytic injection should be used in patients with STEMI before the referral.