Pediatric En Bloc Kidney Transplants: Clinical and Immediate Postoperative US Factors Associated with Vascular Thrombosis

Purpose To evaluate clinical and immediate postoperative ultrasonographic (US) risk factors associated with vascular thrombosis of pediatric en bloc kidney grafts. Materials and Methods This institutional review board-approved HIPAA-compliant retrospective study consisted of 195 recipients of pediatric en bloc kidney grafts throughout a 10-year period. The average recipient and donor age was 45 years (range, 7-74 years) and 9 months (range, 0-84 months), respectively. Clinical factors and immediate postoperative US findings were assessed. Categorical variables were evaluated by using the Fisher exact test and linear models with generalized estimating equations. Results Seventeen patients (23 kidneys) experienced thrombotic events. In six patients (eight kidneys), thrombosis occurred intraoperatively. The remaining 11 patients (15 kidneys) received a diagnosis of thrombosis on postoperative days 1-13. Recipients more than 40 years old had a higher incidence of arterial thrombosis than did younger recipients (eight of 62 vs three of 133, respectively; P < .01). Recipients were more likely to develop thrombosis with donor weight less than 5 kg (10 of 52 vs seven of 140 with donor weight of ≥ 5 kg; P < .01), with intraoperative perfusional concern (10 of 21 vs seven of 174 without; P < .01), or with right-sided allograft placement (10 of 64 vs seven of 131 left sided; P = .03). At US of the 15 postoperative thrombotic events, the incidence of thrombosis was greater when donor arterial velocity was less than 100 cm/sec (seven of 56 vs four of 126 with velocity ≥ 100 cm/sec; P = .04). An intrarenal arterial resistive index of less than 0.6 was associated with higher incidence of arterial thrombosis (nine of 123 vs zero of 217, respectively; P = .01). A resistive index greater than 0.8 was associated with a higher incidence of venous thrombosis (four of 13 vs one of 217, respectively; P = .04). Conclusion Clinical factors and immediate US findings can help stratify patients receiving pediatric en bloc kidneys into risk categories for vascular thrombosis that, if proven in prospective studies, could affect immediate postoperative treatment. (©) RSNA, 2015.