Considerations For Use of Propensity Score Matching in Specific Patient Populations—Reply

Abstract

culated MEAF score on this subset of 70 patients is consistent with early allograft dysfunction analysis, indicating that preservation using OCS liver resulted in significantly lower MEAF scores within the overall subset (mean [SD], 3.45 [1.71] vs 4.90 [2.02]; P = .002) as well as for donation after circulatory death donors (mean [SD], 2.87 [1.96] vs 5.94 [1.40]; P = .009) when compared with the control group.That the OCS group contained a higher number of donation after circulatory death donors was the result of a higher number of organ declines in the control arm. We agree with Romero and Kalashnikov that this makes the findings of superiority when using the OCS liver all the more remarkable.Regarding concerns the authors raise about the potential for NMP to widen disparities, it is important to note that the costs of OCS liver are already fully reimbursed through the US Centers for Medicare & Medicaid Services under the organ acquisition cost report for all Medicare patients. In addition, following US Food and Drug Administration approval, a national program has been established to provide support services, consisting of surgical and perfusionist expertise, to any transplant program anywhere in the country wishing to use normothermic machine perfusion (NMP). This infrastructure diminishes workload barriers that might prevent a transplant center from using NMP to support and preserve a donor liver. The future impact of this NMP service on access and outcomes for liver transplant recipients in general, as well as specific populations, will require additional study.PROTECT results indicate that NMP is advantageous for the preservation of donor livers and offer the opportunity for organ assessment not afforded by oxygenated cold perfusion. 4 The widespread integration of NMP in donor procurement practices is ongoing and leading to a paradigm shift in our field with the potential to further enhance organ management during NMP to reap even greater benefits in the future.