Significance of microvascular thrombosis in renal allografts: role of ex vivo thrombolytic therapy.

BACKGROUND: Microvascular thrombosis is an uncommon pathologic finding in cadaveric kidneys. It is associated with disseminated intravascular coagulation most frequently associated with head injuries and massive blood transfusions. The high rate of non-function published in the literature portends an ominous significance for transplanted organs, which have been discarded by many transplant centers.
METHODS: In this report, we document the effectiveness of ex vivo thrombolytic therapy with activase, a plasminogen activator, injected intra-arterially in 12 kidneys with extensive histologic intraglomerular microvascular thrombosis prior to transplantation. All cold stored cadaveric kidneys were flushed for 50 min with 50 mg of activase diluted in University of Wisconsin solution. Pre-flush and post-flush wedge biopsies were performed on the allografts.
RESULTS: All biopsies showed complete resolution of the intraglomerular microthrombi following activase flush. One kidney clotted in the third week. Three patients developed delayed graft function (25%) of which one experienced allograft thrombosis following one month after transplantation. All remaining grafts are still functioning at a mean follow up of 55.1 months (range: 23-71) with a mean serum creatinine of 1.8 mg/dL (range: 0.8-2.5).
CONCLUSIONS: Back table flush with activase rapidly lyses severe intraglomerular microthrombi making them successfully transplantable. Pre-treatment with activase seems to be an effective therapeutic intervention for kidneys with massive intraglomerular thrombosis.