Intrapatient Variability in Tacrolimus Exposure Does Not Predict The Development of Cardiac Allograft Vasculopathy After Heart Transplant.

Abstract

A high intrapatient variability in tacrolimus exposure is associated with poor long-term outcomes after kidney transplant. We hypothesized that a high intrapatient variability of tacrolimus exposure after heart transplant may be associated with cardiac allograft vasculopathy as a determinant of long-term survival of heart transplant recipients. Eighty-six heart transplant recipients were included. Patients underwent coronary angiography at years 1 and 4 after transplant and were divided according to low and high intrapatient variability of tacrolimus exposure, with the median variability as cut-off. The primary outcome was the association between tacrolimus intrapatient variability and the progression of cardiac allograft vasculopathy score between years 1 and 4. Secondary outcome was this association with acute cellular rejection. There was no significant difference in the proportion of patients with high tacrolimus intrapatient variability in the group that progressed to higher grades of cardiac allograft vasculopathy (n = 15) versus the group without progression (n = 71) at 4-year follow-up (60.0% vs 47.9%; P = .57). There was no significant difference in the proportion of patients with high tacrolimus intrapatient variability between the 58 patients with 1 or more acute cellular rejection episodes and the 28 patients without rejection (51.7% vs 46.4%; P = .82). A high intrapatient variability in tacrolimus exposure does not appear to influence heart transplant outcomes, unlike its influence on kidney transplant function. A higher immunosuppression exposure after heart transplant, including the use of prednisone often in a combination of 3 immunosuppressive drugs, may protect against the effects of high intrapatient tacrolimus variability.