Clinical and pathological features of thrombotic microangiopathy influencing long-term kidney transplant outcomes
Cínthia Montenegro Teixeira, Hélio Tedesco‐Silva, Luiz A. Moura, Henrique Proença, Renato de Marco, Maria Gerbase de Lima, Marina Pontello Cristelli, Laila Almeida Viana, Cláudia Rosso Felipe, José Osmar Medina Pestana
Abstract
INTRODUCTION: Thrombotic microangiopathy (TMA) in post-transplant setting has heterogeneous clinical manifestations. METHODS: We retrospectively studied data of 89 patients with post-transplant TMA, which was characterized by thrombi in at least one glomerulus and/or arteriole. Systemic TMA was defined by thrombocytopenia and microangiopathic anemia and early onset TMA, when occurred less than 90 days post transplant. RESULTS: The cumulative incidence was 0.93%. The majority of the recipients were young (mean age 39 years), female (52%) and Caucasian (48%) with primary kidney disease of unknown etiology (37%). Early TMA occurred in 51% of the patients and systemic TMA, in 25%. Underlying precipitating factors were: infection (54%), acute rejection (34%), calcineurin inhibitor toxicity (13%) and pregnancy (3%). 18% of the patients had several triggers. Glomerular TMA was observed in 50% of the biopsies and endothelial cell activation, in 61%. The 1-year patient survival was 97% and corresponding graft survival, 66%. Allograft survival was inferior when acute antibody mediated rejection (ABMR) occurred (with 41%; without 70%, p = 0.01), however no differences were determined by hemolysis, time of onset, thrombi location or endothelial cell activation. CONCLUSIONS: Our results suggest that post-transplant TMA is a rare but severe condition, regardless of its clinical and histological presentation, mainly when associated to ABMR.