Renal Artery Orientation Influences the Renal Outcome in Endovascular Thoraco-abdominal Aortic Aneurysm Repair

Objective: To evaluate the impact of renal artery (RA) anatomy on the renal outcome of fenestrated-branched endografts (FB-EVAR) for thoraco-abdominal aortic aneurysms (TAAA). Methods: Between 2010 and 2016, all patients undergoing FB-EVAR for TAAA were prospectively collected. Anatomical, procedural, and post-operative data were retrospectively analysed. RA anatomy was assessed on volume rendering, multi planar and centre line reconstructions by dedicated software (3Mensio). RA diameter, length, ostial stenosis/calcification, orientation and aortic angles of the para-visceral aorta were evaluated. RA orientation was classified in four types: A (horizontal), B (upward), C (downward), D (downward + upward). RA revascularisation by fenestrations or branches was considered. Inability to cannulate and stent RA (RA loss), early RA occlusion (within three months), and composite RA events (one among RA loss, intra-operative RA lesion, RA related re-interventions, RA occlusion) were assessed. Results: Seventy-three patients (male 77%; age 73 ± 6 years) with 39 (53%) type I, II, III and 34 (47%) type IV TAAA, underwent FB-EVAR, for a total of 128 RAs. The mean RA diameter and length were 6 ± 1 mm and 43 ± 12 mm, respectively. Type A, B, C, and D orientations were 51 (40%), 18 (14%), 48 (36%), and 11 (10%) RAs, respectively. Angulation of para-visceral aorta >45° was present in 14 cases (19%). Ostial stenosis and calcifications were detected in 20 (16%) and 16 (13%) RAs, respectively. Branches and fenestrations were used in 43 (34%) and 85 (66%) RAs, respectively. There were four (3%) intra-operative RA lesions (2 ruptures, 2 dissections). Ten (8%) RAs were lost intra-operatively because of the inability to cannulating and stenting. On univariable analysis, type B RA orientation (p =.001; OR 13.2; 95% CI 3.2–53.6), para-visceral aortic angle > 45° (p =.02; OR 4.9; 95% CI 1.3–18.5) and branches (p =.003; OR 9.0; 95% CI 1.9–46.9) were risk factors for intra-operative RA loss; type C RA orientation was a protective factor (p =.02; OR 0.1; 95% CI 0.01–0.9). On multivariable analysis, type B RA orientation (p =.03; OR 5.9; 95% CI 1.1–31.1) and branches (p =.03; OR 7.3; 95% CI 1.1–47.9) were independent risk factors for intra-operative RA loss. Fourteen patients suffered post-operative renal function worsening (> 30% of the baseline). The mean follow up was 19 ± 12 months. Four (3%) early RA occlusions occurred in three patients (2 single kidney patients required permanent haemodialysis). Type D RA orientation (p =.00; RR 17.8; 8.6–37.0) and branches (p =.004; RR 3.2; 2.4–4.1) were risk factors for early RA occlusion on univariable analysis. Five patients (7%) required early RA related re-interventions (recanalisation + relining 3; stent graft extension 1; parenchymal embolisation 1). No late RA occlusion or re-interventions were reported during follow up. Composite RA events occurred in 17 (13%) cases. Type B (p =.05; OR 3.9; 95% CI 1.1–15.7) or D (p =.006; OR 10.9; 95% CI 2.3–50.8) RA orientations and branches (p =.006; OR 5.7; 95% CI 1.6–20.3) were independent predictors of composite RA events on multivariable analysis. Conclusion: Renal artery orientation significantly affects the early RA outcome of FB-EVAR for TAAA. Intra-operative RA loss is predicted by type B RA orientation and branches, while early RA occlusion is predicted by type D orientation and branches. The present data suggest that in TAAA, fenestrations should be the first choice for renal revascularisation in type B and D RA orientations.