Application of a Novel CT-Based Iliac Artery Calcification Scoring System for Predicting Renal Transplant Outcomes

Objective: The objective of our study was to assess whether the degree and distribution of iliac artery calcifications as determined by a CT-based calcium scoring system correlates with outcomes after renal transplant.

Materials and methods: A retrospective review of renal transplant recipients who underwent CT of the pelvis within 2 years before surgery yielded 131 patients: 75 men and 56 women with a mean age of 52 years. Three radiologists assigned a separate semiquantitative score for calcification length, circumferential involvement, and morphology for the common iliac arteries and for the external iliac arteries. The operative and clinical notes were reviewed to determine which iliac arterial segment was used for anastomosis, the complexity of the operation, and whether delayed graft function (DGF) occurred. Renal allograft survival and patient survival were calculated using the Kaplan-Meier technique.

Results: Excellent interobserver agreement was noted for each calcification score category. The common iliac arteries showed significantly higher average calcification scores than the external iliac arteries for all categories. Advanced age and diabetes mellitus were independently predictive of higher scores in each category, whereas hypertension, cigarette smoking, hyperlipidemia, and sex were not. Based on multivariate analysis, only the calcification morphology score of the arterial segment used for anastomosis was independently predictive of a higher rate of surgical complexity and of DGF. None of the scores was predictive of graft or patient survival. However, patients with CT evidence of iliac arterial calcification had a lower 1-year survival after transplant than those who did not (92% vs 98%, respectively; p = 0.05).

Conclusion: Only the calcification morphology score of the arterial segment used for anastomosis was significantly predictive of surgical complexity and of DGF. Routine pretransplant CT for calcification scoring in patients of advanced age or those with diabetes mellitus may enable selection of the optimal artery for anastomosis to optimize outcomes.