Does an open chest predict hospital mortality in adult venoarterial ecmo?

Introduction: Delayed sternal closure (open-chest) with veno-arterial extracorporeal membrane oxygenation (VA-ECMO) may occur due to central cannulation, bleeding, or intolerance to cardiac compression. An open-chest may be a risk factor for VA-ECMO in-hospital mortality; we tested this hypothesis using our hospital’s ECMO registry. Methods: This is a single-center study of VA-ECMO patients treated between 2011-2021. Pediatric patients, hospital transfers, and perfusion failures were excluded. Univariate comparisons and hierarchical logistic regression were performed. Confounders were entered on regression step one. Results: Death occurred in 94 (67.6%) of 139 patients. Indications included cardiogenic shock (82), post-cardiotomy (29), and rescue (28). Open-chest occurred in 24 patients, 22 of whom were post-cardiotomy. Central cannulation occurred in 19 patients; all were open-chest. Mortality for open-chest was 85.2% (23) vs 63.4% (71) for closed-chest (p=.03). Logistic regression identified blood utilization (p=.001 [OR 1.065]), body mass index (p=.003 [OR 1.129]), renal replacement therapy (p=.038 [OR 2.613]), and ECMO days (p=.029 [OR .864]) as independent predictors of mortality, but not open-chest, central cannulation, or post-cardiotomy (p=.311, .569, and .838 respectively). C-statistic was .776 (p<.001). Blood utilization (29 vs 11 units [p <.001]), and ECMO days (5.69 vs 3.71 days [p=.011]) differed significantly between open and closed-chest. BMI and RRT were not significant (p=.309 and p=.964). Conclusions: While an open chest does not independently predict in-hospital mortality for patients on VA-ECMO, it is a surrogate marker for blood utilization and longer ECMO perfusions. Open-chest may enhance the opportunity for bleeding and prolonged perfusion, but blood utilization and longer time on ECMO are independent predictors of in-hospital mortality.