Risk Factor Analysis of Abdominal Aortic Enlargement after Thoracic Endovascular Aortic Repair Using Two-Stent Graft Implantation for Stanford Type B Aortic Dissection

  Objective  To explore the risk factors of abdominal aortic enlargement (AAE) after thoracic endovascular aortic repair using two-stent graft implantation (TEVAR-TSI) for Stanford type B aortic dissection.

  Methods  The clinical and imaging data of patients who underwent TEVAR-TSI for Stanford type B aortic dissection in the First Affiliated Hospital of Hebei North University from January 2013 through September 2020 were retrospectively collected and analyzed. CT angiography (CTA) scans were performed before the procedure. Follow-up CTA scans were scheduled and performed in 1, 3, 6, and 12 months after the procedure and annually thereafter. The primary outcome was AAE. The risk factors of AAE after TEVAR-TSI were selected and survival analysis and multivariate logistic regression were conducted accordingly.

  Results  A total of 146 patients were regularly followed up at our hospital, with the median followup time of the entire cohort being 48 months (ranging from 12 to 84 months). During the followup period after TEVAR-TSI, the incidence of AAE was 19.9% (29/146). A total of 29 patients developed AAE (the AAE group), while 117 patients did not develop AAE (the non-AAE group). There were a total of 27 deaths, including 13 in the non-AAE group versus 14 in the AAE group. Distal aortic reoperation was performed on 10 patients, including 4 in the non-AAE group versus 6 in the AAE group. The cumulative long-term survival and freedom from distal aortic reoperation of the non-AAE group were both significantly better those of the AAE group (P<0.05). Logistic multivariate regression analysis showed that independent risk factors of AAE after TEVAR-TSI included the following, partial thrombosis of the false lumen (odds ratio OR=4.090, 95% confidence interval CI: 1.539-10.867, P=0.005), the longer cumulative diameter of residual intimal tear above the level of the lowest renal arteries (OR=1.290, 95% CI: 1.164-1.429, P=0.000), and shorter cumulative diameter of residual intimal tear below the level of the lowest renal arteries (OR=0.487, 95% CI: 0.270-0.878, P=0.017).

  Conclusion  The prognosis of patients who developed AAE after TEVAR-TSI was not good. During followup visits, as precautions against the development of AAE, close attention should be paid to partial thrombosis of the false lumen, cumulative diameter of residual intimal tear above the level of the lowest renal arteries, and cumulative diameter of residual intimal tear below the level of the lowest renal arteries.