Strategies in Immunosuppression After Heart Transplantation

Abstract

In this issue of Circulation: Heart Failure , Baran and colleagues1 report on 150 de novo adult heart transplant patients randomized to tacrolimus monotherapy or tacrolimus and mycophenolate mofetil therapy (dual therapy). Corticosteroids were weaned and discontinued in all patients by 8 weeks posttransplantation. Intravascular ultrasound (IVUS) was performed at baseline and at follow-up. The authors find that the primary end point of a composite biopsy score at 6 months was similar for both study groups. They also report no significant difference between groups in 3-year survival and the development of cardiac allograft vasculopathy (CAV) by coronary angiography and IVUS. No patient required reinstitution of corticosteroids or a switch to another immunosuppressive drug during the follow-up period. The authors conclude that early corticosteroid weaning, tacrolimus monotherapy, or dual therapy are potential viable options for heart transplant patients. Article see p 129 For many cardiac transplant physicians, there is a pervasive unease that we have been overimmunosuppressing our patients. To this end, the authors are to be congratulated for pursuing an aggressive reduced immunosuppression regimen early after heart transplantation in the form of tacrolimus monotherapy and dual therapy with mycophenolate mofetil. However, although the basic idea of the study was well conceived, there are several concerns. The most important of these is that the study was underpowered to demonstrate true differences in the primary and secondary end points. Rejection rates were low at 5%, which is consistent with what many centers are now reporting; thus, the number of patients needed to power this study was underestimated. The primary end point of 6-month composite biopsy score is another concern. The authors used the older 1990 International Society for Heart & Lung Transplantation biopsy grading scale. This grading scale is not linear, and the biopsy grading score, although used in other publications, …