Cardiogenic shock: do we need a paradigm shift?

In current international guidelines, intraaortic balloon counterpulsation is considered to be a class I treatment for cardiogenic shock complicating acute myocardial infarction. However, evidence is based mainly on registry data, and there is a paucity of randomized clinical trials. In this randomized, prospective, open-label, multicenter trial, we randomly assigned 600 patients with cardiogenic shock complicating acute myocardial infarction to intraaortic balloon counterpulsation (IABP group, 301 patients) or no intraaortic balloon counterpulsation (control group, 299 patients). All patients were expected to undergo early revascularization (by means of percutaneous coronary intervention or bypass surgery) and to receive the best available medical therapy. The primary efficacy end point was 30-day all-cause mortality. Safety assessments included major bleeding, peripheral ischemic complications, sepsis, and stroke. A total of 300 patients in the IABP group and 298 in the control group were included in the analysis of the primary end point. At 30 days, 119 patients in the IABP group (39.7%) and 123 patients in the control group (41.3%) had died (relative risk with IABP, 0.96; 95% confidence interval, 0.79 to 1.17; P=0.69). There were no significant differences in secondary end points or in process-of-care measures, including the time to hemodynamic stabilization, the length of stay in the intensive care unit, serum lactate levels, the dose and duration of catecholamine therapy, and renal function. The IABP group and the control group did not differ significantly with respect to the rates of major bleeding (3.3% and 4.4%, respectively; P=0.51), peripheral ischemic complications (4.3% and 3.4%, P=0.53), sepsis (15.7% and 20.5%, P=0.15), and stroke (0.7% and 1.7%, P=0.28). The use of intraaortic balloon counterpulsation did not significantly reduce 30-day mortality in patients with cardiogenic shock complicating acute myocardial infarction for whom an early revascularization strategy was planned. (Funded by the German Research Foundation and others; IABP-SHOCK II ClinicalTrials.gov number, NCT00491036.).

In patients who have acute myocardial infarction with cardiogenic shock, early revascularization of the culprit artery by means of percutaneous coronary intervention (PCI) improves outcomes. However, the majority of patients with cardiogenic shock have multivessel disease, and whether PCI should be performed immediately for stenoses in nonculprit arteries is controversial.

Cardiogenic shock remains the major cause of death for patients hospitalized with acute myocardial infarction (MI). Although survival in patients with cardiogenic shock complicating acute MI has been shown to be significantly higher at 1 year in those receiving early revascularization vs initial medical stabilization, data demonstrating long-term survival are lacking. To determine if early revascularization affects long-term survival of patients with cardiogenic shock complicating acute MI. The Should We Emergently Revascularize Occluded Coronaries for Cardiogenic Shock (SHOCK) trial, an international randomized clinical trial enrolling 302 patients from April 1993 through November 1998 with acute myocardial infarction complicated by cardiogenic shock (mean [SD] age at randomization, 66 [11] years); long-term follow-up of vital status, conducted annually until 2005, ranged from 1 to 11 years (median for survivors, 6 years). All-cause mortality during long-term follow-up. The group difference in survival of 13 absolute percentage points at 1 year favoring those assigned to early revascularization remained stable at 3 and 6 years (13.1% and 13.2%, respectively; hazard ratio [HR], 0.74; 95% confidence interval [CI], 0.57-0.97; log-rank P = .03). At 6 years, overall survival rates were 32.8% and 19.6% in the early revascularization and initial medical stabilization groups, respectively. Among the 143 hospital survivors, a group difference in survival also was observed (HR, 0.59; 95% CI, 0.36-0.95; P = .03). The 6-year survival rates for the hospital survivors were 62.4% vs 44.4% for the early revascularization and initial medical stabilization groups, respectively, with annualized death rates of 8.3% vs 14.3% and, for the 1-year survivors, 8.0% vs 10.7%. There was no significant interaction between any subgroup and treatment effect. In this randomized trial, almost two thirds of hospital survivors with cardiogenic shock who were treated with early revascularization were alive 6 years later. A strategy of early revascularization resulted in a 13.2% absolute and a 67% relative improvement in 6-year survival compared with initial medical stabilization. Early revascularization should be used for patients with acute MI complicated by cardiogenic shock due to left ventricular failure. clinicaltrials.gov Identifier: NCT00000552.