Open AccessImpact of mechanical circulatory support on donor heart allocation: past, present, and future
Author(s) -
Robert Tatum,
H. Todd Massey,
Vakhtang Tchantchaleishvili
Publication year - 2021
Publication title -
reviews in cardiovascular medicine
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.555
H-Index - 39
eISSN - 2153-8174
pISSN - 1530-6550
DOI - 10.31083/j.rcm.2021.01.230
Subject(s) - medicine , incentive , extracorporeal membrane oxygenation , united network for organ sharing , intensive care medicine , destination therapy , clinical trial , medical emergency , heart transplantation , heart failure , surgery , cardiology , transplantation , economics , liver transplantation , microeconomics
The United Network for Organ Sharing (UNOS) recently revised its heart allocation policy to address numerous shortcomings of the previous system. Implemented in 2018, the changes sought to reduce waiting list mortality, clearly define urgency status based on objective physiologic variables, decrease exemption requests, and introduce geographic modifications to ensure organ distribution favors the highest urgency candidates. In large part, UNOS policy revisions were driven by the growing use of continuous flow left ventricular assist devices (CF-LVADs) and the relevant device complications that led to an unacceptably high number of status exemptions. The new 6-tiered system assigns a comparatively lower urgency status to patients supported on CF-LVADs and higher urgency to patients supported on short-term mechanical circulatory assist (MCA) such as extracorporeal membrane oxygenation (ECMO) and intraaortic balloon pump (IABP) counterpulsation. LVAD use as bridge to transplant (BTT) therapy increased steadily throughout the preceding decade due to technological improvements and increased physician familiarity, but the recent policy changes introduce incentives for physicians to withhold this life-saving therapy in order to achieve higher urgency status for their patients. This paper will explore the technological evolution of MCA and the pertinent clinical trials that have led to their FDA approval as BTT and destination therapy. A review of the inception and development of the donor allocation system will be provided before examining available post-policy outcome data. Finally, we will highlight successes and shortcomings of the implemented changes before commenting on areas to potentially expand upon the existing policy.