The Prognostic Value of Prehospital Blood Lactate Levels to Predict Early Mortality in Acute Cardiovascular Disease.

Introduction: The knowledge of the prognostic value of prehospital lactate (PLA) is limited. Our objective was to evaluate the predictive capacity of PLA to predict early mortality (within 48 h) from the index event in acute cardiovascular disease (ACVD). Methods: Prospective, longitudinal, multicenter, observational study in patients, attended by advanced life support units, transferred to the emergency department of their reference hospital and diagnosed with ACVD. We collected demographic, physiological, clinical, analytical variables, main cardiological diagnosis, and data on hospital admission and early mortality. The main outcome variable was mortality from any cause within 2 days. Results: Between March 1, 2018 and January 31, 2019, a total of 492 patients were included in our study. Early mortality after the index event within the first 48 h affected 27 patients (5.5%). The most frequent cause of care demand was chest pain with 223 cases (45.3%). The predictive power of PLA to discriminate mortality at 2 days obtained an area under the curve of 0.911 (95% confidence interval [CI]: 0.83-0.98,P < 0.001). A value equal or superior to 4.3 mmol/L globally attained a sensitivity of 92.6% (95% CI, 76.6-97.9) with a specificity of 82.8% (95% CI, 79.1-86.0), with a positive predictive value of 23.8 (16.7-32.8) and a negative predictive value of 99.5 (98.1-99.9). Conclusion: PLA represents a prognostic biomarker with excellent predictive capacity for ACVD. Prehospital Emergency Services (PhEMS) should incorporate this test routinely in their usual procedures.