Selecting Ideal VAD Candidates in Patients on Venoarterial Membrane Oxygenation: Can We Identify the “Point of No Return”?

Objectives: The implantation of permanent ventricular assist devices (VADs) in patients on veno-arterial membrane oxygenation (VA-ECMO) is controversial due to the expected devastating outcome in these patients. The aim of this multicenter study was to identify survival predictors in this cohort of patients.

Methods: Data of patients undergoing continuous flow VAD support at four European institutions between 01.2010 and 09.2017 were retrospectively reviewed. Inclusion criteria were patients with prior VA-ECMO support. Several parameters including patient's characteristics, risk factors, results of blood gas analysis, blood chemistry and catecholamine doses prior to the VAD implantation surgery were analyzed. Uni and multivariate logistic regression analysis was performed to identify survival predictors.

Results: A total of 99 patients with continuous flow VADs met the inclusion criteria. The VA-ECMO cannulation was peripheral in 92% of patients. The 30 day and long-term mortality was 19 and 46% respectively. The mean VA-ECMO duration prior to VAD implantation was 6.3 ± 5.1 days in non-survivors versus 6.8 ± 6.3 days in survivors (p = 0.70). Cardiopulmonary bypass was used in 67% of the patients at the time of VAD implantation. Univariate regression analysis identified pre-LVAD Model for End-stage Liver Disease (MELD) score (OR: 1,173, 95% CI: 1,084–1,270; p < 0.001), lactate level (OR: 2,055, 95% CI: 1,302–3,201, p = 0.001) and leucocyte value (OR: 1,101, 95% CI: 1,000–1,220; p = 0.05) as potential predictors of 30-day mortality. However, MELD score was the only significant parameter in multivariate regression analysis (p = 0.01). Preoperative MELD score >30 predicted 100% mortality. Postoperative complications included right heart failure requiring right VAD in 43 patients (44%), bleeding requiring resternotomy in 22 patients (22%), respiratory failure in 55 patients (57%), renal failure in 55 patients (56%), hepatic failure in 40 patients (41%).

Conclusion: In this largest reported series of VAD patients with prior VA-ECMO support, pre VAD-MELD score seems to be the most important factor predicting outcome after VAD implantation. A high MELD score reveals worsening end-organ function on VA-ECMO and identifies patients who would not benefit from permanent VAD implantation. Survival in VAD patients with prior VA-ECMO remains limited and associated with significantly higher postoperative complications compared with VAD patients without prior VA-ECMO support.