Vascular graft thrombosis after pancreatic transplantation: univariate and multivariate operative and nonoperative risk factor analysis.

Background: Vascular thrombosis is still the leading cause of nonimmunologic, technical pancreatic transplant graft failures. The paucity of published data--coupled with our large institutional experience with pancreatic transplantation in all recipient and transplant categories, using a wide spectrum of surgical techniques--provided the impetus for a retrospective study of graft thrombosis risk factors.
Study Design: Four hundred thirty-eight patients with pancreatic transplants (45 percent simultaneous pancreas-kidney [SPK], 23 percent pancreas-after-kidney [PAK], and 32 percent pancreatic transplants alone [PTA] and with Type I insulin-dependent diabetes mellitus were studied retrospectively. Of 438 pancreatic transplants, 90 percent were bladder-drained and 10 percent were enteric-drained. Ninety-three percent were from cadaver donors, 90 percent were whole-organ grafts, and 20 percent were retransplantations. Quadruple immunosuppression was given. For bladder-drained, whole-organ transplantations (n=378), we performed Cox regression analyses to study the impact on pancreatic graft thrombosis of donor, recipient, mode of preservation, and surgical variables.
Results: The overall thrombosis rate was 12 percent (5 percent arterial, 7 percent venous). For cadaver, bladder-drained, whole-organ pancreatic transplants, the thrombosis incidence was highest in PAK recipients (20 percent). The PAK category was also found to be an independent risk factor for thrombosis by stepwise Cox regression analysis. In separate stepwise Cox regression analyses for each category, other identified risk factors for thrombosis included the following: donor age (PAK, PTA); cardiocerebrovascular cause of donor death (SPK, PAK); the use of an aortic Carrel patch (SPK); arterial pancreatic graft reconstruction using a splenic artery to superior mesenteric artery anastomosis (SPK, PTA) or an interposition graft between the splenic artery and the superior mesenteric artery (PTA); portal vein extension graft (PAK); left-sided implantation into the recipient (PAK); and graft pancreatitis (defined as hyperamylasemia exceeding five days post-transplant [PAK, PTA]).
Conclusions: Older donors or those who died of cardiocerebrovascular disease should not be considered for any recipient category. Preservation time needs to be minimized and strategies need to be developed to decrease graft pancreatitis. Surgically, left-sided implantation and arterial reconstructions other than the Y-graft also increase risk, as do portal vein extensions. Renal transplants alone in prospective PAK recipients with Type I diabetes mellitus should, therefore, always be implanted left-sided to allow for right-sided pancreatic graft placement.