Precannulation International Normalized Ratio is Independently Associated With Mortality in Veno-Arterial Extracorporeal Membrane Oxygenation

Abstract

Objectives: To explore whether precannulation international normalized ratio (INR) is associated with in-hospital mortality in venoarterial extracorporeal membrane oxygenation (VA-ECMO) patients.

Design: A retrospective, observational cohort study.

Setting: A quaternary care academic medical center.

Participants: Patients with cardiogenic shock on VA-ECMO for >24 hours.

Interventions: None, observational study.

Measurements and main results: A total of 188 patients who were on VA-ECMO were included over three years. Patients were stratified into three groups based on their pre-ECMO INR: INR <1.5, INR 1.5 to 1.8, and INR >1.8. For all patients, demographics, comorbidities, and ECMO details were recorded. The study's primary outcome was in-hospital mortality and secondary outcomes included major bleeding, minor bleeding, allogeneic transfusion, ischemic stroke, intracranial hemorrhage, acute renal failure, acute liver failure, gastrointestinal bleeding, intensive care unit and hospital lengths of stay. A multivariate logistic regression was used to determine whether precannulation INR was associated independently with in-hospital mortality. In-hospital mortality differed significantly by INR group (51.6% INR >1.8 v 42.3% INR 1.5-1.8 v 24.3% INR <1.5; p = 0.004). In a multivariate logistic regression model, precannulation INR >1.8 was associated independently with an increased odds of mortality (odds ratio, 2.48; 95% confidence interval, 1.05-6.04) after controlling for sex, Survival after VA- ECMO score, and ECMO indication. An INR within 1.5 to 1.8 did not confer an increased mortality risk.

Conclusions: An INR >1.8 before VA-ECMO cannulation is associated independently with in-hospital mortality. Precannulation INR should be considered by clinicians so that ECMO resources can be better allocated and risks of organ failure and intracranial hemorrhage can be better understood.

Keywords: ECMO; INR; cardiogenic shock; coagulation.