Afterload mismatch-related problems after "domino" heart transplantation

The heart transplants with domino technique, which uses donor hearts from heart-lung recipients, increases the pool of donors, provides the advantage of shortening the ischemic time and makes suitable hearts for patients with pulmonary hypertension. The present study aimed to characterise the pre- and post-transplant clinical and hemodynamic profiles of patients that underwent domino transplant in Pavia.

Between 1991 and 1992, 9 heart transplants were performed with the domino procedure at I.R.C.C.S. Policlinico S. Matteo of Pavia. Domino donors (6 with primary pulmonary hypertension, 2 with Eisenmenger's syndrome due to atrial septal defect, 1 with cystic fibrosis) underwent electrocardiographic, echocardiographic, chest roentgenogram studies, and right heart catheterization and coronary angiography (for donor older than 40). Domino recipients, 6 males and 3 females with a mean age of 44 years, had dilated cardiomyopathy (4 cases), coronary artery disease (4 cases) and valvular heart disease (1 case) (group 1). Seven of the 9 cases entered the study; 2 were excluded: one because had undergone heterotopic transplantation, the other had received the heart from another country and therefore the graft had suffered from a very long ischemic time. Controls group consisted of 12 patients who had consecutively undergone cardiac transplantation with non-domino donors during the same period (group 2). Immunosuppression was similar in both groups, and consisted of a combination of cyclosporin A, azathioprine and corticosteroids, plus a 7-day-course of antithymocyte globulin. Hemodynamic and echocardiographic controls were performed at 2, 3 and 4 weeks (short-term control) and at 2 and 6 months (mid-term control) after surgery.

Domino donors (39 +/- 12.5 years) had significantly higher mean right ventricular end-diastolic diameter and lower left ventricular diameter than normal mean values. Domino recipients had significantly higher mean pulmonary arteriolar resistances than controls; mean ischemic time was also significantly lower in group 1 than in group 2. Short- and mid-term controls after surgery in group 1 showed persistently higher systemic vascular resistances and pulmonary vascular resistances and lower cardiac output than in group 1. Two patients developed an early and unexpected increase in pulmonary wedge pressure accompanied by severe paroxysmal nocturnal dyspnea and mitral regurgitation. In all cases, the left ventricles were relatively inadequate; the combination of low cardiac output and of high systemic vascular resistances favoured the occurrence of an afterload mismatch condition that was worsened by chronic hypoxia. This condition must be known and expected in these patients after transplantation in order to provide timely and effective treatment to potentially life-threatening left ventricular failure episodes. IN CONCLUSION, the subset of transplanted patients that receives domino donors may develop left-side afterload mismatch which, combined with low cardiac output, with high systemic vascular resistances and with the effects of chronic hypoxia originally suffered by the heart, may cause sudden and unexpected left-side heart failure which has to be timely recognised and managed. Although hemodynamic adaptation of this patients is highly problematic, it does not limit the value of the domino procedure.