PROGNOSTIC IMPACT OF JUXTA-RENAL INNER VESSEL DIAMETER AND VERTICAL DISTANCE IN RENAL ARTERY OUTCOMES AFTER FENESTRATED ENDOVASCULAR REPAIR.

Aim: The aim of this retrospective multicenter study is to evaluate the impact of juxta-renal inner vessel diameter (JR-IVD) and vertical distance between renal arteries (RA-VerDi) on renal artery instability (RAI) and associated complications in patients undergoing fenestrated endovascular aortic repair (FEVAR) for complex aortic pathology.

Methods: Patients undergoing FEVAR with custom-made stent grafts at six referral hospitals between 2017 and 2023 were included. Data on patient demographics, anatomical characteristics, stent configurations, and outcomes were collected. Patients were divided into tertiles and categorized into three groups: JR-IVD <20mm, JR-IVD 20-24mm, and JR-IVD >24mm. RA-VerDi was determined by measuring the distance between the center of the lowest renal artery and the highest renal artery, based on the planning specifications for each custom-made graft. The primary outcome was freedom from RAI, with secondary outcomes including renal artery stenosis/occlusion, endoleak, and reintervention. Statistical analyses were performed using MedCalc software, with logistic regression and Kaplan-Meier survival curves employed to assess outcomes.

Results: In total, 520 RAs among 260 patients were analyzed. The technical success rate was 98.7%, with a 30-day mortality rate of 2.3%. After a mean follow-up of 26.9 months (±28.1, range 1-154), RAI was observed in 5.6% of cases, including stenosis/occlusion (3.2%) and endoleak (2.2%). Freedom from RAI at 12, 24, and 48 months was 95.8% (SE 0.01), 93.5% (SE 0.01), and 90.7% (SE 0.01), respectively. JR-IVD <20 mm was identified as a significant risk factor for renal artery stenosis/occlusion (p=0.01), though it did not increase the risk of RAI or reintervention compared to larger JR-IVDs. A correlation was found between RA-VerDi and RAI, with smaller vertical distances associated with higher RAI risk (OR: 0.89, 95% CI: 0.82-0.99, p=0.05), but no significant cutoff was determined. Severe renal artery stenosis was an independent predictor of RAI (OR: 13.28, 95% CI: 3.1-55.86, p=0.004).

Conclusions: The use of fenestrated custom-made grafts in patients with JR-IVD <20 mm may increase the risk of renal artery complications, particularly stenosis/occlusion. Although a correlation between RA-VerDi and RAI was observed, a definitive predictive cutoff could not be established. Attention should be given to patients with severe renal artery stenosis, as this condition seems to be an independent predictor of RAI.