Short-term clinical outcome of normotensive patients with acute PE and high plasma lactate.

BACKGROUND

Strategies for identifying normotensive patients with acute symptomatic PE at high risk of PE-related complications remain to be defined.

METHODS

This prospective cohort study aimed to determine the role of plasma lactate levels in the risk assessment of normotensive patients with acute PE. Outcomes assessed over the 7 days after the diagnosis of PE included PE-related mortality and haemodynamic collapse, defined as need for cardiopulmonary resuscitation, systolic blood pressure <90 mm Hg for at least 15 min, need for catecholamine administration, or need for mechanical ventilation.

RESULTS

Between December 2012 and January 2014, the study enrolled 496 normotensive outpatients with acute symptomatic PE. PE-related complications occurred in 20 (4.0%; 95% CI 2.5% to 6.2%) of the 496 patients. These patients had higher baseline lactate levels (median 2.66 mmol/L; IQR 1.56-5.96 mmol/L) than patients without complications (1.20 mmol/L; IQR 1.20-2.00 mmol/L) (p<0.001). Overall, 135 patients (27.2%) had plasma lactate ≥2 mmol/L. Fourteen (10.4%) of them had PE-related complications versus 6 of 361 patients with low lactate (negative predictive value 98.3%; p<0.001). Patients with elevated plasma lactate had an increased rate of PE-related complications (adjusted OR 5.3; 95% CI 1.9 to 14.4; p=0.001) compared with those with low lactate. The combination of elevated plasma lactate with markers of right ventricular dysfunction (by echocardiogram) and myocardial injury (by cardiac troponin) was a particularly useful prognostic indicator (positive predictive value 17.9%; 95% CI 6.1% to 36.9%).

CONCLUSIONS

Plasma lactate represents a powerful predictor of short-term PE-related complications and may provide guidance for decision-making in PE care.