Severe Obesity Is Not a Contraindication to Veno-venous Extracorporeal Support: Outcomes in Patients with BMI ≥35

M. Platten¹, H. Rajjoub¹, P. Rothenberg¹, N. Teman², B. Jalil¹, P. McCarthy¹, P. Sappington¹, V. Badhwar¹, A. Hayanga¹, K. Quedado^1
1West Virginia University, morgantown, West Virginia ²University of Virginia, Charlottesville, Virginia

Purpose: Severe obesity classified as body mass index (BMI) ≥ 35 kg/m2 is considered a contraindication to extracorporeal support. There are, nevertheless, increasing reports to challenge this position. We sought to evaluate outcomes associated with the use of venovenous extracorporeal membrane oxygenation (VV-ECMO) in this cohort of patients.

Methods: We performed a single-institution retrospective analysis on patients who required VV- ECMO between May 2020 to December 2021. All patients were ≥ 18 years of age with a BMI ≥ 35 kg/m2 who fulfilled clinical criteria for extracorporeal support. A total of 181 patients had a BMI ≥ 35 kg/m2. Data were collected on survival, time to discharge, time to decannulation, time to tracheostomy, and time to extubation. Statistical analysis involved t-tests, chi-square tests, and Kaplan-Meier survival plots, time-to-event models, and multiple linear regressions to evaluate differences between outcomes. Exploratory analysis evaluated the distribution and variance of categorical variables such as gender, race, insurance type, and ECMO indications. Cox proportional hazards models were applied to analyze time-to-event data, adjusting for potential confounders such as age, gender, PRESERVE score, mechanical ventilation days before ECMO, and ECMO indications.

Results: A total of 181 patients were studied and 80 patients had a BMI ≥ 35 kg/m2. Mean age was 43.5 (+/-13.5) years old and most were Male (59.7%) and White (97.2). 54% had between 12 and 24 hours of mechanical ventilation prior to cannulation. Patients with a BMI ≥ 35 kg/m2 had a significantly shorter time to discharge (HR: 1.97, 95% CI: 1.16 - 3.36, p = 0.013), and exhibited a lower likelihood of death following discharge compared to those with BMI ˂ 35 kg/m2 (HR: 0.169, 95% CI: 0.036 - 0.799, p = 0.025). Patients in the higher BMI group also had higher survival rates at discharge (78.8% vs. 63.4%, p = 0.037). Time to decannulation (19.5 ± 22.4 days vs. 20 ± 22.4 days, p = 0.883) and time to extubation (14.6 ± 14.6 days vs. 5.64 ± 19.2 days, p = 0.135) did not differ significantly between cohorts.

Conclusion: Our findings suggest that patients with BMI ≥ 35 kg/m2 do not have worse outcomes from ECMO. These results challenge using BMI ≥ 35 kg/m2 as a contraindication to ECMO candidacy. Further prospective studies are, nevertheless, necessary to better characterize this relationship.

Identify the source of the funding for this research project: NIH NHLBI # 2UM1 HL088925 12