SAFETY AND EFFICACY OF ENDOVASCULAR TREATMENT FOR CONGENITAL RENAL ARTERIOVENOUS FISTULAS.

Introduction: Congenital renal arteriovenous fistulas (AVF) represent an uncommon and varied group of diseases, with a reported prevalence of 0.04%. Despite rare they are clinically relevant as burdened with risk of right heart failure or aneurysmal evolution with possible rupture.

Material And Methods: Patients undergone treatment for a congenital renal AVF at our Institution over the last 10 years were identified on a prospectively maintained electronic database and treatment strategies and related outcomes were investigated according to the STROBE guidelines. A comprehensive literature review was also performed using Google Scholar and PubMed database between 1, January 2010 and December 2023, 31 with the aim to investigate the results of endovascular strategies in this setting.

Results: Among 163 embolization procedures for vascular lesions of the renal vessels performed during the study period six cases (4 women; median age 53 years, range 41-75 years) of congenital renal AVF were identified at the computed angiotomography (CTA). All cases were unilateral type 2 AVFs and diagnosed on a computed angiotomography . Two (33.3%) patients were asymptomatic but presented with a growing lesion, three (50%) suffered from abdominal/lumbar pain, and one (16.6%) had gross haematuria. All patients underwent embolization of feeding vessels (n=4, 66.7%) or segmental arteries (n=2, 33.3%) with either one or more embolic agent (coils, N-Butyl CyanoAcrylate, or BioTrombina®). Clinical success rate was 100% with the evidence of complete exclusion of the vascular lesion at the imaging. No systemic nor renal complications were detected, and no further interventions were required. Mean postoperative creatinine and haemoglobin were 1.10 mg/dL (range: 0,86 mg/dL - 1.33 mg/dL) and 11.05 g/dL (range: 9.9 g/dL - 12.2 mg/dL) respectively versus 0.86 mg/dL (range: 0.67 mg/dL - 1.10 mg/dL) and 11.9 g/dL (range: 10,8 g/dL - 13 mg/dL) respectively preoperatively. The 6-months follow-up CTA showed obliteration of the renal AVF in all cases. A comprehensive literature review identified 72 relevant cases (n=51, 70.8% symptomatic) from 6 retrospective case series with a population ranging between 6 and 24 patients. Coils (n=25, 34.6%) or an association of several embolic agents (n=30, 41.6%) were the most used followed by Gelatin sponge particle, polyvinyl alcohol, N-Butyl CyanoAcrylate, Onyx or Amplatzer in the remaining cases. Immediate clinical success ranged between 65% and 100% with an overall clinical success rate between 88% and 100%. No migration of the embolic agent no recurrences were reported in most of series and no impact on renal function was described in any case.

Conclusion: Despite surgical approaches may be required in selected cases, endovascular embolization represent a valid option in treatment of renal arteriovenous fistulas with low risk of complications and satisfactory mid-term results.