Abstract 15745: Antibody-Mediated Rejection is Associated with Microvasculopathy after Heart Transplantation
Purpose. Antibody-mediated rejection (AMR) and microvasculopathy are associated with poor survival after heart transplantation (HTx). Following the new guidelines of the ISHLT we tested the effect of AMR on the development of microvasculopathy (MVP) in biopsy.
Methods. We prospectively studied 134 pts (117 men, mean age 50 yrs) who underwent endomyocardial biopsy at 4 weeks (n=134), 1 yr (n=107) and 3 yrs (n=61) after HTx. Acute cellular rejection (ACR; ISHLT), MVP (ratio of luminal radius to diameter of vessel wall) and endothelial swelling were evaluated in H&E stainings. AMR was assessed by immunohistochemistry (CD31-positive capillaries to CD68, IgG, IgA, IgM, C1q and C3c; all x200).
Results. At 4 weeks, 1 yr and 3 yrs, MVP affected 36%, 48% and 43% of pts, and AMR was present in 37%, 8% and 10% of pts, respectively. Pts with AMR more frequently presented with MVP at 4 weeks (47% vs. 22%; p=0.010), 1 yr (74% vs. 46%; p=0.006) and 3 yrs after HTx (81% vs. 45%; p=0.013). AMR was significantly correlated to ACR, e.g. at 4 weeks 43% (p<0.001) and at 1 yr 50% (p=0.006) of pts presented with concurrent ACR. However, only pts with MVP at 3 yrs post-transplant presented more often preceding ACR of any grade at 4 weeks after HTx (29% vs. 5%; p=0.025). Otherwise ACR was not correlated to MVP. Endothelial swelling was significantly correlated to concurrent MVP at 4 weeks (74% vs. 33%; p<0.001) and 1 yr (61% vs. 32%; p=0.001) and also to future development of MVP at 3 yrs post-transplant (62% vs. 32%; p=0.009; 52% vs. 32%; p=0.066). Only at 1 yr post-transplant was endothelial swelling correlated to AMR (100% vs. 45%; p=0.002).
Conclusions. AMR is associated with microvasculopathy after HTx in the early, mid- and long-term follow-up. Microvasculopathy in biopsy should trigger screening for AMR and additional biopsy follow-up to identify high risk patients.
- © 2012 by American Heart Association, Inc.