Lactate Values and Mortality in Patients With Cardiogenic Shock: Insights From the Altshock-2 Registry

Objectives: We aimed to evaluate the prognostic role of baseline and 24-hour plasma lactates in patients with cardiogenic shock (CS). Design: Multicenter, observational, prospective Altshock-2 Registry (NCT04295252) enrolling patients with CS since March 2020. Setting: Multicenter Italian Registry (12 centers). Patients: Six hundred fifty-one consecutive patients with CS and available data on lactate values. Interventions: None. Measurements and Main Results: The association of baseline and 24-hour lactates with in-hospital mortality (primary endpoint) was evaluated. The optimal lactate cutoff points for predicting outcomes were identified in the overall cohort and among patients treated with mechanical circulatory support (MCS). Among the 651 included patients with CS, the mean age was 64 ± 14 years and 76% were male. On admission, patients with lactates less than 2.0, 2.1-4.0, and greater than 4.0 mmol/L were 248 (38.1%), 172 (26.4%), and 231 (35.5%), respectively. An improvement in lactate values at 24 hours was observed in 76.5% of patients. Baseline and 24-hour lactates were both independently associated with increased mortality (adjusted odds ratios for each 1-mmol/L increase: 1.08 [95% CI, 1.02-1.14] for baseline lactate; and 1.37 [95% CI, 1.15-1.63] for 24-hr lactate), but 24-hour lactates had a higher predictive accuracy than baseline lactates (area under the curve 0.702 vs. 0.648). The optimal baseline and 24-hour lactate cutoffs for predicting mortality were 3.2 mmol/L and 1.7 mmol/L, respectively, and varied in patients treated with MCS at different time points. Conclusions: Higher baseline and 24-hour lactates were both independently associated with increased in-hospital mortality in patients with CS, although the 24-hour value had a higher predictive accuracy. Optimal lactate cutoffs for predicting mortality varied between admission and 24 hours and according to the MCS strategies.