OUTPATIENT INOTROPIC THERAPY IN HEART-TRANSPLANT CANDIDATES - SHOULD ITS USE INFLUENCE WAITING LIST PRIORITY STATUS

Background: The use of outpatient intravenous inotropic therapy in hea rt transplant candidates is contentious. In addition to concerns about morbidity and mortality rates, the current United Network for Organ S haring (UNOS) heart allocation system presently grants no waiting list priority status benefit to candidates who receive intravenous inotrop ic therapy in the outpatient setting (UNOS status 2), whereas identica l therapy given in an intensive care unit setting does increase priori ty status (UNOS status I). The goal of this study was to determine whe ther an increase in UNOS waiting list priority status is justified in heart transplant candidates receiving outpatient intravenous inotropic therapy by comparing the waiting list mortality of UNOS status 2 cand idates on such therapy with that of UNOS status 2 candidates maintaine d on oral heart failure agents alone. Methods: This is a retrospective analysis of the pretransplantation outcomes of heart transplant candi dates initially listed as UNOS status 2, comparing 29 candidates recei ving intravenous outpatient inotropic therapy (group 1)to 109 candidat es maintained on oral heart failure agents alone (group 2). Results: T he waiting list mortality was not significantly different between the two groups (group 1 = 7% vs group 2 = 20%, p.18); however, group 1 pat ients had greater morbidity rates while awaiting transplantation than group 2 patients. A greater percentage of group 1 than group 2 patient s clinically deteriorated to UNOS status 1 while awaiting transplantat ion (45% vs 11%), resulting in more group I patients undergoing transp lantation overall, (59% vs 33%, p =.01) and more group I than group 2 patients undergoing transplantation at a higher priority status, UNOS status 1 (76% vs 33%, p.003). Group 1 patients had more pretransplanta tion heart failure admissions (1.2 vs 0.6 admissions/total waiting per iod, p.02) and longer hospital stays (26 +/- 39 vs 8.8 +/- 16 days, p =.03), spent a greater percentage of their total waiting time hospital ized (7% vs 2%, p.003), and were more likely than group 2 patients to receive intravenous inotropic therapy during hospitalization (70% vs 2 5%, p =.001). Conclusion: This study suggests that heart transplant ca ndidates who require maintenance outpatient intravenous inotropic ther apy represent a subgroup of UNOS status 2 candidates with greater wait ing list morbidity, but no greater waiting list mortality than candida tes who can be maintained on oral heart failure agents alone. However, the current UNOS heart allocation system provides for this increased illness acuity by assigning a higher priority status when necessary. A larger, prospective study is necessary to determine whether a true di fference in waiting list mortality rates exists and if an increase in priority status is justified for UNOS status 2 candidates requiring ma intenance inotropic therapy.