Normothermic ex vivo allograft blood perfusion in clinical heart transplantation.
BACKGROUND
Cold ischemia associated with cold static storage is an independent risk factor for primary allograft failure and survival of patients after orthotopic heart transplantation. The effects of normothermic ex vivo allograft blood perfusion on outcomes after orthotopic heart transplantation compared to cold static storage have been studied.


METHODS
In this prospective, nonrandomized, single-institutional clinical study, normothermic ex vivo allograft blood perfusion has been performed using an organ care system (OCS) (TransMedics, Andover, MA, USA). Included were consecutive adult transplantation patients who received an orthotopic heart transplantation (oHTx) without a history of any organ transplantation, in the absence of a congenital heart disorder as an underlying disease and not being in need of a combined heart-lung transplantation. Furthermore, patients with fixed pulmonary hypertension, ventilator dependency, chronic renal failure, or panel reactive antibodies >20% and positive T-cell cross-matching were excluded. Inclusion criteria for donor hearts was age of <55 years, systolic blood pressure >85 mmHg at the time of final heart assessment under moderate inotropic support, heart rate of <120 bpm at the time of explantation, and left ventricular ejection fraction >40% assessed by an transcutaneous echo/Doppler study with the absence of gross wall motion abnormalities, absence of left ventricular hypertrophy, and absence of valve abnormalities. Donor hearts which were conventionally cold stored with histidine-tryptophan-ketoglutarate solution (Custodiol; Koehler Chemie, Ansbach, Germany) constituted the control group. The primary end point was the recipients' survival at 30 days and 1 and 2 years after their heart transplantation. Secondary end points were primary and chronic allograft failure, noncardiac complications, and length of hospital stay.


RESULTS
Over a 2-year period (January 2006 to July 2008), 159 adult cardiac allografts were transplanted. Twenty-nine were assigned for normothermic ex vivo allograft blood perfusion and 130 for cold static storage with HTK solution. Cumulative survival rates at 30 days and 1 and 2 years were 96%, 89%, and 89%, respectively, whereas in the cold static storage group survival after oHTx was 95%, 81%, and 79%. Primary graft failure was less frequent in the recipients of an oHTx who received a donor heart which had been preserved with normothermic ex vivo allograft blood perfusion using an OCS (6.89% versus 15.3%; P = .20). Episodes of severe acute rejection (23% versus 17.2%; P = .73), as well as, cases of acute renal failure requiring haemodialysis (25.3% versus 10%; P = .05) were more frequent diagnosed among recipients of a donor heart which had been preserved using the cold static storage. The length of hospital stay did not differ (26 days versus 28 days; P = .80) in both groups.


CONCLUSIONS
Normothermic ex vivo allograft blood perfusion in adult clinical orthotopic heart transplantation contributes to better outcomes after transplantation in regard to recipient survival, incidence of primary graft dysfunction, and incidence of acute rejection.