C. M. Png1, R. O. Tadros1, P. L. Faries1, S. Kim1, W. Beckerman1, M. R. Torres1, Z. M. Feldman1, M. L. Marin1 1Mount Sinai School Of Medicine,New York, NY, USA
Introduction: Follow up computed tomography angiography (CTA) scans add considerable post implantation costs to endovascular aneurysm repairs (EVAR) of abdominal aortic aneurysms (AAA). By building a risk model, we hope to identify patients at low risk for postoperative complications in order to minimize unnecessary CT scans.
Methods: 557 consecutive patients were reviewed. Probit models were created for four outcomes: aneurysm sac enlargement, reintervention, type I/III endoleaks and type II endoleaks, using preoperative aneurysm morphology, patient demographics and operative details as covariates. Patients with an abnormal 30 day post operative CT scan were excluded. Time points chosen for analysis were 1-year, 2-year, 3-years and 10-year post EVAR. A combined model including three outcomes was also created.
Results: Individual models that showed most significance were aneurysm sac enlargement at 1-year post EVAR (n=411; Sensitivity=1; Specificity=0.47; Accuracy 0.48) and reintervention at 2-year post EVAR (n=494; Sensitivity=1; Specificity=0.42; Accuracy=0.45). Notably, our models reported that increasing iliac artery diameter and increasing aortic neck angle increased the risk for a reintervention, while increasing iliac artery tortuosity increased the risk for a type I/III endoleak. Similarly, almost all statistically significant covariates were qualitatively supported by prior literature. Our final combined model would prevent the need for post-EVAR CTA in 59 patients (16%) at 1 year, 26 (7%) patients at 2 years and 6 (2%) patients at 3 years with 100% sensitivity. (Table 1)
Conclusion: Our model is a robust predictor of patients at low risk for post AAA EVAR complications. With additional validation and refinement, it could be applied to practices to cut down on the overall need for post-implantation CTA. Reducing the number of CT scans will reduce post-implantation cost and radiation exposure.
