Background: Renal allograft thrombosis is a serious complication of kidney transplantation that ultimately leads to graft loss. Its association with acute and hyperacute rejection is well documented; however, in a large proportion of patients the precise cause remains obscure. The exact incidence and the associated risk factors for those episodes of graft thrombosis lacking evidence of rejection have not yet been clearly established.
Methods: All reported episodes of graft thrombosis in 558 consecutive cadaveric kidney transplants performed in a single centre were examined to identify those without histopathological evidence of rejection, i.e. primary renal graft thrombosis. Univariate and multivariate types of analysis were applied to study the possibly related risk factors and any associated morbid event(s) of those episodes. Recipients without reported episodes of primary renal graft thrombosis (n = 493) represented the control group for the 34 identified cases.
Results: The calculated incidence of primary renal graft thrombosis was 6% (1.9% arterial, 3.4% venous and 0.7% both), comprising 45% of early (90 days) and 37% of 1-year graft losses in our centre. The multivariate analysis identified five independent risk factors for primary renal graft thrombosis: donor's right kidney P < 0.007, past history of venous thrombosis (renal or extrarenal) P = 0.000, and diabetic nephropathy P = 0.000 of the recipient, technical surgical problems P = 0.000, and recipient's haemodynamic status peri and early postoperatively P < 0.001. Primary renal graft thrombosis was related to the presentation with delayed graft function (DGF) P < 0.0005 and was significantly associated with extrarenal thromboembolic manifestations P < 0.0005. There was no association between primary renal graft thrombosis and recipient's age, sex, number of previous transplants, type of dialysis, pretransplant treatment with erythropoietin, antiplatelet agents, or oral anticoagulants, donor's age, sex, number or graft vessels, warm and cold ischaemia times, site of transplant (R/L iliac fossa) and type of immunosuppressive agent used for induction whether cyclosporin A (CsA) or OKT3.
Conclusions: Primary renal graft thrombosis is an important cause of graft loss that may be accompanied by thrombosis of extrarenal sites and effective, safe prophylactic regimens are needed, especially for those at high risk.