Prognostic value of plasma lactate in acute pulmonary embolism: the multicentre Thrombo-Embolism Lactate Outcome study

Abstract

Purpose: To investigate the prognostic value of plasma lactate in patients with acute pulmonary embolism (PE). In particular, we tested if high plasma lactate at presentation (> 2 mmol/L) was associated with high incidence (>10%) of death or hemodynamic collapse duo to PE in the short-term. Methods: We studied adult outpatients with symptomatic, objectively confirmed PE presenting to five emergency departments, four in Italy and one in Spain Plasma lactate and troponin-I levels were measured at presentation. We considered lactate values >2mmol/L and troponin-I values >0.10 ng/ml to be abnormal Right ventricular dysfunction (RVD) was assessed by echocardiography. The primary endpoint was a composite of PE-related mortality or haemodynamic collapse within 7 days after diagnosis of PE. Haemodynamic collapse was defined as progression to shock, need for mechanical ventilation, or need for cardiopulmonary resuscitation. We tested the association between lactate >2mmol/L and the study endpoints using Cox-proportional-hazards regression analysis. Secondary outcomes were 30-day all-cause mortality or recurrent fatal and nonfatal PE. We scheduled to include 330 patients. Results: For the first 180 patients enrolled in the study, the mean age was 69.9±16.3 years and 97 (53.9%) were women. Fourteen patients (7.8%) showed shock or hypotension (systolic arterial pressure<100 mmHg) at presentation, 80 (40%) had RVD, 45 (25%) showed high troponin-I and 43 (23.9%) showed high lactate values. Seven patients (3.8%) died and 4 (2.2%) patients had nonfatal haemodynamic collapse within 7 days after diagnosis of PE. All-cause mortality was 7.8% at 30 days. Primary endpoint incidence was higher in the lactate-positive group compared to the lactate-negative group (16.3%, [95% CI 8.3-22.4%] vs. 2.9% [95% CI 0.08-7.3%]). After adjusting for shock, hypotension, RVD and troponin I, elevated plasma lactate was associated with a significant increase inthe risk for the primary endpoint (HR 3.9, 95% CI 1.08-14.55) Conclusions: Patients with PE and elevated plasma lactate are at high risk (>10%) of death or haemodynamic collapse in the short-term, independent of shock/hypotension or RVD/injury markers. Plasma lactate could be useful to guide early management of PE patients in the emergency department.