A retrospective comparison of survivors and non-survivors of massive pulmonary embolism receiving veno-arterial extracorporeal membrane oxygenation support.

INTRODUCTION: While the optimal care of patients with massive pulmonary embolism (PE) is unclear, the general goal of therapy is to rapidly correct the physiologic derangements propagated by obstructive clot. Extracorporeal membrane oxygenation (ECMO) in this setting is promising, however the paucity of data limits its routine use. Our institution expanded the role of ECMO as an advanced therapy option in the initial management of massive PE. The purpose of this project was to evaluate ECMO-treated patients with massive PE at an academic medical center and report shortterm mortality outcomes.

METHODS: Thirty-two patients placed on ECMO for confirmed, massive PE from January 2012 to December 2015 were retrospectively analyzed. All patients had PE confirmed by computerized tomography and/or invasive pulmonary angiography.

RESULTS: In our population of patients managed with ECMO, 21 (65.6%) patients survived to decannulation and 17 (53.1%) survived index hospitalization. Baseline characteristics and clinical variables showed no difference in age, gender, right ventricular-to-left ventricular ratios, or peak troponin-T between survivors and non-survivors. Non-survivors tended to have a previous history of malignancy. Cardiac arrest prior to ECMO cannulation was associated with worse outcomes. All 5 patients who received concomitant systemic thrombolysis died, while 11 of 15 patients who received catheter-directed thrombolysis survived. A lactic acid level ≤6mmol/L had an 82.4% sensitivity and 84.6% specificity for predicting survival to discharge.

CONCLUSION: The practical approach of utilizing ECMO for massive PE is to reserve it for those who would receive the greatest benefit. Patients with poor perfusion, for example from cardiac arrest, may gain less benefit from ECMO. Our findings indicate that a serum lactate >6mmol/L may be an indicator of worse prognosis. Finally, in our patient population, catheter-directed thrombolytics was effectively combined with ECMO.