Trends in cardiogenic shock: report from the SHOCK Study

AIMS: We analysed time trends in patient characteristics, management, and outcomes of cardiogenic shock complicating acute myocardial infarction in the international, prospective SHOCK Trial Registry and pre-study Registry. BACKGROUND: Despite therapeutic advances in its management, the incidence and high mortality of this complication has remained unchanged for decades. However, in recent years mortality was reported to decrease in one community concomitant with increasing use of revascularization. METHODS: Thirty-six centres registered 1380 patients with suspected cardiogenic shock complicating acute myocardial infarction from January 1992 to August 1997. Patient and myocardial infarction characteristics, haemodynamics, medications, procedure use, and vital status at discharge were recorded. RESULTS: In all, 79% of patients had shock due to predominant pump failure (non-mechanical aetiology). The aetiology, patient profile, and clinical characteristics of cardiogenic shock did not differ over time, except for increases in the incidence of prior bypass surgery (P=0.054) and transfers to tertiary centres (P=0.008). In all, 44% underwent revascularization (n=485), with angioplasty performed more often than bypass surgery (69% vs 31%). The revascularization rate increased over time (P=0.006) with a significant decrease in the time to revascularization (P=0.033). The use of Swan-Ganz catheterization decreased over time (P=0.018), as did the mean length of hospitalization (P=0.034). Overall in-hospital mortality was high (63%) but decreased over time in all patients (P=0.004) and those with pump failure (P=0.018). Mortality was lower for patients who underwent revascularization compared to those who were not revascularized (41% vs 79%, P<0.001). CONCLUSIONS: Cardiogenic shock complicating acute myocardial infarction is associated with a high mortality rate, but mortality decreased significantly from 1992 to 1997. This partly reflects the greater use of revascularization, which was associated with better outcomes. The reported international trend towards shorter admissions for myocardial infarction was also observed in this cohort.