Acute Cellular Rejection Early after Heart Transplantation Does Not Reduce Exercise Capacity in the First Year

Abstract

BackgroundEarly graft dysfunction after orthotopic heart transplantation is associated with worse survival and functional outcomes. However, the prognostic implication of acute cellular rejection (ACR) early after transplant is less well defined. Here, we analyzed the association between early ACR and post-transplant exercise capacity.MethodsWe performed a retrospective analysis of all heart transplant patients who underwent cardiopulmonary exercise testing (CPET) within a year of transplant at a single large academic center between 2000 and 2011. Early ACR was defined as cellular grade 2R or 3R histopathology seen on biopsy within 3 months of transplant. Exercise capacity was assessed during CPET by 1) peak VO2 and 2) total exercise time. CPET performed prior to diagnosis of rejection were excluded. The association between early ACR or grade of ACR and exercise parameters was analyzed using linear regression.ResultsA total of 230 patients (median age 55 [IQR 45-61], 79.6% male) who received a heart transplantation at our institution between 2000 and 2011 underwent CPET during the 1st year. Of these, 12% (n=40) developed early grade 2R rejection and 5% (n=12) developed early grade 3R rejection. No antibody mediated rejection (including hyperacute) was seen in this timeframe among patients who later underwent CPET. Neither peak VO2 (p=0.95) nor total exercise time (p=0.54) were predicted by early ACR of any grade.ConclusionsEarly cellular rejection does not predict worse exercise capacity in the first year after heart transplant. This inference is limited to patients who are able to undergo CPET. Early graft dysfunction after orthotopic heart transplantation is associated with worse survival and functional outcomes. However, the prognostic implication of acute cellular rejection (ACR) early after transplant is less well defined. Here, we analyzed the association between early ACR and post-transplant exercise capacity. We performed a retrospective analysis of all heart transplant patients who underwent cardiopulmonary exercise testing (CPET) within a year of transplant at a single large academic center between 2000 and 2011. Early ACR was defined as cellular grade 2R or 3R histopathology seen on biopsy within 3 months of transplant. Exercise capacity was assessed during CPET by 1) peak VO2 and 2) total exercise time. CPET performed prior to diagnosis of rejection were excluded. The association between early ACR or grade of ACR and exercise parameters was analyzed using linear regression. A total of 230 patients (median age 55 [IQR 45-61], 79.6% male) who received a heart transplantation at our institution between 2000 and 2011 underwent CPET during the 1st year. Of these, 12% (n=40) developed early grade 2R rejection and 5% (n=12) developed early grade 3R rejection. No antibody mediated rejection (including hyperacute) was seen in this timeframe among patients who later underwent CPET. Neither peak VO2 (p=0.95) nor total exercise time (p=0.54) were predicted by early ACR of any grade. Early cellular rejection does not predict worse exercise capacity in the first year after heart transplant. This inference is limited to patients who are able to undergo CPET.