ADULT ORTHOTOPIC HEART-TRANSPLANTATION USING UNDERSIZED PEDIATRIC DONOR HEARTS - TECHNIQUE AND POSTOPERATIVE MANAGEMENT

Background Because of the critical shortage of adult donor hearts, man y recipients die awaiting transplantation of an organ of appropriate s ize. Undersized hearts (donor/recipient weight ratio <0.7) have been u sed for heterotopic heart transplantation. We report on 6 moribund adu lt heart transplant candidates who were rescued with orthotopic heart transplantation of undersized pediatric hearts. Methods and Results Re cipients were hypotensive (mean blood pressure, 62.3+/-13.4 mm Hg), ha d high pulmonary artery pressures (mean pulmonary artery pressure, 42. 4+/-6.3 mm Hg), and had mean cardiac indexes of 1.7+/-0.6 L.min(-1).m( -2). Four had pretransplant intra-aortic balloon pumps, and one was on a Thoratec left ventricular assist device complicated by fungemia. Si nce conventionally sized donors were unavailable (+/-30% recipient wei ght), the patients were listed in a wider weight range (+/-60%). Donor characteristics were age, 8.7+/-1.5 years; weight, 32.8+/-7.0 kg; and donor/recipient weight ratio, 0.44+/-0.2, with average ischemic time of 236.0+/-59.3 minutes. Technical considerations during transplantati on included (1) opening the donor right atrium from the inferior vena cava to superior vena cava to facilitate size matching, (2) performing size-mismatched pulmonary artery and aortic anastomoses end to end, ( 3) infusing prostaglandin E(1) 12 ng.kg(-1).min(-1) to decrease pulmon ary and systemic vascular resistance, (4) pacing donor and recipient a tria synchronously to improve ventricular filling, (5) maintaining hig h heart rates up to 140 beats per minute (initially with isoproterenol or pacing, chronically with theophylline), (6) hyperventilating with sedation and paralysis as necessary, (7) reperfusing with triiodothyro nine, and (8) minimizing afterload. All patients were discharged from the hospital. At 1 week, hemodynamics were normal and echocardiograms demonstrated left ventricular growth. Conclusions Hence, undersized pe diatric hearts can be used successfully to salvage moribund patients a nd expand the potential donor pool for adult orthotopic heart transpla ntation.