Venous lactate as a tool for the Risk-Stratification of patients with acute pulmonary embolism: A retrospective cohort study

Introduction

Prognostication in pulmonary embolism (PE) is crucial due to the broad range of clinical severity, and biomarkers such as arterial lactate are considered helpful markers for illness severity. Venous lactate is more readily accessible, but its prognostic value in acute PE has not been widely evaluated. We aimed to determine optimal cutoffs for venous lactate in predicting adverse outcomes in patients with PE.

Methods

We performed a retrospective study of normotensive (systolic blood pressure > 100 mmHg) patients presenting with imaging-confirmed PE severe enough to require Pulmonary Embolism Response Team (PERT) activation and a venous lactate measured clinically within 24 h of activation. Data were extracted from an ongoing registry of PERT patients at a single, tertiary academic medical center. The primary outcome was clinical deterioration defined by a composite of clinical events occurring within 7 days, including death, catheter-based intervention, systemic thrombolysis, extracorporeal membrane oxygenation (ECMO), or intubation. We performed a receiver operating characteristic (ROC) curve analysis, calculated the area under curve (AUC), and calculated optimal cutoff value using the least distance from (0,1).

Results

We included 145 patients in the final analysis. Mean age was 64 years and 61 (43 %) were female. 36 patients (26 %) met the composite outcome. The AUC of the ROC curve was 0.56, and the optimal cutoff for venous lactate was 1.8 mmol/L, corresponding to 58 % sensitivity and 61 % specificity.

Conclusion

In a cohort of normotensive patients with severe acute PE, venous lactate was not significantly associated with acute deterioration. Our findings do not support the use of venous lactate for prognostication of clinical deterioration in patients with PE severe enough to warrant PERT activation.