Serum Lactate and A Relative Change in Lactate as Predictors of Mortality in Patients with Cardiogenic Shock - Results from The Cardshock Study

INTRODUCTION: Cardiogenic shock complicating acute myocardial infarction has a very high mortality. Our present study focuses on serial measurement of lactate during admission due to cardiogenic shock and the prognostic effect of lactate and a relative change in lactate in patients after admission and the institution of intensive care treatment. METHODS AND RESULTS: This is a secondary analysis of the CardShock study. Data on lactate at baseline were available on 217 of 219 patients.In the study population, the median baseline lactate was 2.8 mmol/L (min-max range, 0.5-23.1 mmol/L).At admission, lactate was predictive of 30-day mortality with an adjusted Hazard ratio (HR) of 1.20 mmol/L (95% confidence interval, CI 1.14-1.27). Within the first 24 h of admission, baseline lactate remained predictive of 30-day mortality. Lactate at 6 h had a HR of 1.14 (95% CI 1.06-1.24) and corresponding values at 12 and 24 h had a HR of 1.10 (1.04-1.17), and of HR 1.19 (95% CI 1.07-1.32), respectively. A 50% reduction in lactate within 6 h resulted in a HR of 0.82 (95% CI 0.72-0.94). Corresponding hazard ratios at 12 and 24 h, were 0.87 (95% CI 0.76-0.98) and 0.74 (95% CI 0.60-0.91), respectively. CONCLUSION: The main findings of the present study are that baseline lactate is a powerful predictor of 30-day mortality, lactate at 6, 12, and 24 h after admission are predictors of 30-day mortality, and a relative change in lactate is a significant predictor of survival within the first 24 h after instituting intensive care treatment adding information beyond the information from baseline values.