LAUSR

Circulation. 2019;140:e940–e941. DOI: 10.1161/CIRCULATIONAHA.119.042541 e940 Nirvik Pal, MD Aaron Lim, MD Mark Nelson, MD To the Editor: We read the article by Truby et al1 with great interest. The expert authors once again demonstrate that given the risk factors (propensity-matched), bridge to transplantation with a left ventricular assist device (LVAD) confers significantly higher risk of early posttransplantation mortality. Although the findings are not new and have been shown before (body mass index,2 glomerular filtration rate3), they are in contrast to the conclusions from another recent review by another expert in the field, Dardas.4 Although LVAD improves wait-list survival (primary reason for implantation), complications of LVAD and certain patient profiles are associated with poor outcomes after heart transplantation. First, in our opinion, patients receiving LVAD as a bridge to transplantation after failing medical optimization are physiologically an entirely different entity compared with those who never needed an LVAD before heart transplantation. This is alluded to in the Discussion by the authors that any cross-sectional assessment of organ function at 1 point in time may not capture the natural history of the device therapy. In other words, registrybased variables are treated as discrete, whereas in the clinical course, they may be more continuous in nature. Second, we would like to caution the reader that the United Network for Organ Sharing database over time incorporates and reflects ever-modifying changes in evolving technology (in this case, axial flow to centrifugal flow to hydrodynamic to magnetic levitation), selection strategy, donor criteria, and organ allocation, depending on the sample time period. This may be a reason that the same United Network for Organ Sharing database has resulted in several studies with contradictory results in the present context. Third, with increasingly clinically efficient LVAD pumps, it is probably time to refocus our perspective and to start emphasizing prospective trials for medical optimization with LVAD therapy before heart transplantation (pulmonary hypertension, renal function, etc) for improved posttransplantation outcomes (bridge to candidacy), rather than investing more in comparative studies between 2 incongruous groups. Last, more future trials for optimal timing5 for both LVAD implantation and heart transplantation need to be determined so that the maximal benefits of device optimization can be achieved before complications of the device take precedence.