Should Lactate Be Included in Assessing Risk for Acute Pulmonary Embolism - A Single Center Retrospective Analysis

ABSTRACT

Introduction: Pulmonary embolism (PE) is a common form of thromboembolism which has a variable and non-specific presentation that can often be fatal. The Simplified Pulmonary Embolism Severity Index (sPESI) which includes hemodynamic parameters of perfusion has been shown to correlate with 30-day mortality in patients with acute PE. The purpose of this quality improvement project was to compare how lactate and sPESI perform in predicting clinical outcomes at our institution with the hopes of developing institutional guidelines for management of patients admitted with an acute PE. Methods: We conducted a single center retrospective analysis on patients admitted to the intensive care unit with a new diagnosis of PE between the years 2016-2021. Patients were identified using ICD-9 CM codes. Exclusion criteria included current or prior positive testing for SARS-CoV-2 (COVID-19). We performed univariant, multivariant, and ROC (Receiver Operating Characteristic) analysis to assess correlations between all cause mortality, lactate elevation, and sPESI. Our covariants included age, sex, Body Mass Index, prior or current history emphysema/COPD, smoking, CKD, diabetes, cancer, atrial fibrillation, and CHF. All analysis was carried out using software R version 3.6.3. Results: Of the 161 patients who were included in the study, the mean age was 60 years (SD 17 years) and 38% (61/161) were females. 31 patients (19.3%) were deceased. Mean BMI of study participants was 29.9 kg/m2. Comorbidities included 9.9% (16/161) with emphysema/COPD, 44% (71/161) with active or prior history of smoking, 6% (10/161) with CKD, 12% (20/161) with diabetes, 15% (24/161) with diagnosis of cancer, 15% (24/161) with atrial fibrillation, 15% (24/161) with history of CHF. We found that in univariant analysis, both sPESI (p=3.4∗10∧-6, AUC = 0.74) and lactate (p=1.1∗10∧-7, AUC = 0.71) correlate with mortality. When included in the same multivariant model, both lactate (p=1.3∗10∧-5) and sPESI (p=3.2∗10∧-4) retained their statistical significance with mortality. Conclusion: As in previous studies, our analysis confirms these results (lactate p=1.1∗10∧-7;AUC = 0.71, sPESI p=3.4∗10∧-6, AUC = 0.74). However, we also demonstrate that both lactate and sPESI retain statistical significance when both are included in the same multivariant model (p-value for lactate = 1.3∗10∧-5, p-value for sPESI = 3.2∗10∧-4). Thus, both lactate and sPESI each demonstrate independent statistical significance, contributing to prediction of mortality. This finding makes a compelling case for inclusion of lactate in risk stratification models used by Pulmonary Embolism Response Teams (PERT) across institutions for triaging the management of acute pulmonary embolism in the hospital.