Interim Data Analysis-—Heparin vs. Bivalirudin and ECMO Oxygenator Performance

D. P.. Vakil¹, J. Magloire¹, E. August², J. Parreco³, T. Song¹, J. Garcia¹, I. Wang^1
1Memorial Healthcare System, Hollywood, Florida ²Memorial Regional Hospital, Hollywood, Florida ³Memorial Healthcare System, Wellington, Florida

Purpose: Extracorporeal membrane oxygenation (ECMO) oxygenator exchanges contribute to the overall cost of an ECMO unit. There are no studies that have examined the relationship between heparin vs. bivalirudin and ECMO oxygenator performance. The study aims to examine and compare ECMO oxygenator performance between patients who were on heparin and bivalirudin.

Methods: A retrospective cohort study was conducted of 92 ECMO patients who were admitted to a single institution from January 1, 2014 to January 30, 2024. Patients were included if they were at least 18 years of age and were placed on anticoagulation from the time of ECMO initiation. Patients were excluded if they were not on anticoagulation and if they changed anticoagulants during the ECMO run. Patient and ECMO characteristics were examined. Patients were split into cohorts based on the anticoagulation (heparin vs bivalirudin). The following are the primary outcomes- at least one oxygenator exchange, multiple oxygenator exchanges, and time to first oxygenator exchange. Chi-squared univariable analysis and multivariable logistic regression were used to compare the outcomes between the groups. The Student’s t-test was used to compare the time to the first oxygenator exchange. The two cohorts were later divided into sub-groups- venoarterial ECMO (VA-ECMO) and venous-venous ECMO (VV- ECMO).

Results: A total of 92 ECMO patients were included in this study: 41 ECMO patients were on heparin (30 VA-ECMO and 11 VV-ECMO) with an average age of 52 years, 66% male, and 53% minorities. 51 ECMO patients were on bivalirudin (VA-ECMO 32 and VV-ECMO 19) with an average age of 49 years, 71% male, and 69% minorities. Patient and ECMO characteristics are displayed in Table 1. There was no statistically significant difference in ECMO duration between the heparin cohort (16 days) versus the bivalirudin cohort (17 days). In the heparin cohort, 17% required at least one oxygenator exchange. In the bivalirudin cohort, 18% required at least one oxygenator. This difference was not significant- bivalirudin had an odds ratio of 2.39 (95% confidence interval [0.32, 18.08]. p-value= 0.398). There are non-significant differences between the two cohorts for requiring multiple oxygenator exchanges. The average time to first oxygenator exchange for the heparin cohort is 17.4 days and for the bivalirudin group it is 13.3 days. There was no significant difference. These findings are displayed in figure 1A. Stratification by ECMO type is displayed in figure 1B (VA-ECMO) and figure 1C (VV-ECMO).

Conclusion: The interim data analysis suggests there are no significant differences in ECMO oxygenator performance based on anticoagulation with heparin versus bivalirudin. However, stratification by VA- ECMO vs. VV-ECMO suggests there could be differences. Further studies to determine the relationship between ECMO anticoagulant and oxygenator performance may optimize ECMO costs and efficiency.

Identify the source of the funding for this research project: No funding was used for this project.