Risk stratification using serum lactate in patients undergoing surgical pulmonary embolectomy

Surgical pulmonary embolectomy (SPE) has been around since the early days of cardiac surgery. But with the increase in thrombolytic and intervention options, indications of SPE have been limited. Literature suggests that risk stratification has been a key step in getting good results. We are analyzing serum lactate levels for risk stratification in massive and submassive pulmonary embolism (PE).

This study is a retrospective analysis of 82 cases that underwent SPE between January 1997 and January 2020. Patients were divided into two groups stratified by venous serum lactate levels on the first admission (Group I: normolactatemia <2 mmol/L, Group II: hyperlactatemia, >2 mmol/L). Primary endpoints were all-cause in-hospital mortality and secondary endpoints were cardiopulmonary bypass time, extracorporeal membrane oxygenator (ECMO) insertion, low cardiac output, blood product use, and right ventricular functions in the follow-up.

Our study had an overall follow-up of 23 years with a median of 3.18 years. Overall, the in-hospital mortality rate was 8.54%. Group II had a higher mortality rate (P = .015) and morbidity incidences like cardiopulmonary bypass time (P = .008), ECMO insertion (P = .036), and open chest after surgery (P = .015). Although 5-year survival was better in group I a compared to group II (81%, 95% CI, 69%-93% vs 65%, 95% CI, 46%-84%), the log rank test showed no statistical survival difference among both groups on long-term follow-up.

Long term survival after SPE is good and these results can further be improved by proper PE risk stratification. Alongside computed tomography and echocardiography, the importance of biomarkers like serum lactate can be explored in the PE management algorithm.