Serum Lactate, an Independent Prognostic Marker in Normotensive Patients With Acute Pulmonary Thromboembolism

Objective Serum lactate, a marker of tissue hypoxia, is an important prognostic factor in sepsis, trauma, and cardiogenic shock. Data on the direct correlation of serum lactate and in-hospital mortality in normotensive acute pulmonary thromboembolism (APE) patients, however, remains scarce. Material and methods We analyzed normotensive APE patients admitted to our clinic from January 1, 2014, to December 31, 2021. Serum lactate was collected from arterial blood at admission. Results The study sample included 161 patients with an average age of 68.61 ± 11.54 years. 54.94% were female. In-hospital mortality was 19.88%. In ROC analysis, serum lactate was a predictor of in-hospital mortality with an AUC of 0.662 (95%CI 0.584 – 0.735, p = 0.005). The cut-off level identified by the Youden index-associated criterion was > 38 mg/dL (34.38% sensitivity, 94.57% specificity). In multivariable analysis for in-hospital mortality alongside the biomarkers proposed by the 2019 ESC guidelines for severity assessment, lactate > 38 mg/dL was an independent predictor of mortality (OR 10.92, 95%CI 3.04 – 39.29, p < 0.001). The prediction model including PESI score, right ventricular dysfunction, troponin I, and lactate > 38 mg/dL had the best predictive performance for in-hospital mortality (AUC 0.807, p < 0.001). Conclusions Elevated serum lactate is an independent predictor of all-cause in-hospital mortality of normotensive APE patients, with the optimal cut-off > 38 mg/dL. Adding the lactate level for mortality prediction outperformed the 2019 ESC guidelines algorithm for severity assessment of normotensive APE patients.