Skip to main content

Vascular-Urinary Fistula

Vascular-urinary fistula covers two clinically distinct entities: the arterioureteral fistula (AUF / UAF) — a communication between an artery (most often the iliac) and the ureter — and the renal arteriovenous fistula (AVF) — a communication between a renal artery branch and a renal vein. AUF is the more clinically urgent: rare but potentially lethal, with rising incidence driven by chronic ureteral stents and pelvic oncologic surgery / radiation.[1][2]

See also: The Ureters, Pelvic Vascular Anatomy, Fistulas landing page.

Part 1 — Arterioureteral Fistula (AUF)​

Definition​

An arterioureteral fistula is an abnormal communication between an artery — most commonly the iliac — and the ureter. It has been described as a "wolf in sheep's clothing" because of its deceptive presentation with intermittent hematuria that can rapidly escalate to life-threatening hemorrhage.[3]

Epidemiology​

  • Estimated nationwide incidence in the Netherlands ~3.5 cases / year.[4]
  • Mean age 66 years (range 29–90).[5]
  • Female predominance ~59%, reflecting the higher prevalence of pelvic malignancies (cervical, uterine) requiring surgery and radiation in women.[5]
  • Reported cases have risen substantially over the past two decades, attributed to growing use of chronic indwelling ureteral stents and improved survival of pelvic-cancer patients.[1][2]

Classification​

ClassDescription
Primary AUFRare; direct erosion of a native (typically aneurysmal) iliac artery into the ureter without prior surgery. Most often associated with aortoiliac aneurysmal disease.[6]
Secondary AUFThe vast majority; occurs in patients with prior pelvic surgery, radiation, vascular grafting, and / or chronic ureteral stenting. The dominant form in contemporary practice.[1][6]

Etiology and Risk Factors​

Risk factorPrevalence among AUF patients
Chronic indwelling ureteral stent72–80%[1][2]
History of pelvic surgery~87%[2]
Pelvic malignancy67–70%[1][2]
Pelvic radiotherapy45–88%[1][2][3]
Prior aortoiliac vascular surgeryVariable (especially primary AUF)[4][5]
Ileal-conduit urinary diversionImportant subset[6][7]

The archetypal AUF patient has a history of pelvic cancer (cervical, colorectal, bladder), prior surgery and radiation, and a chronic indwelling ureteral stent for malignant or post-treatment ureteral obstruction.[1][2]

Pathophysiology​

The mechanism converges on the anatomic crossing of the ureter and iliac artery:[1][5][6]

  1. Anatomic proximity — the ureter crosses anterior to the common iliac bifurcation; 47.7% of AUF occur at the common iliac.[5]
  2. Loss of protective tissue planes — pelvic surgery and radiation destroy the fibrofatty layer separating ureter from artery.
  3. Chronic ureteral stent irritation — the rigid stent exerts continuous mechanical pressure at the crossing point and prevents the ureter from moving away from the artery.
  4. Radiation-induced arterial wall injury — endarteritis obliterans weakens the arterial wall and predisposes to pseudoaneurysm and fistulization.
  5. Vascular graft erosion — synthetic graft material from prior aortoiliac reconstruction can erode into the adjacent ureter.[6][9][10]

A rigid foreign body (stent) pressing against a weakened arterial wall in a scarred, devascularized tissue bed creates the conditions for fistula formation.

Location​

ArteryFrequency[5]
Common iliac47.7%
External iliac35.7%
Internal iliac10.6%
AortaRare
Other (femoral, renal)Rare

Clinical Presentation​

The hallmark is hematuria with a characteristic pattern:[1][2][3][5]

  • Hematuria in 98.7–99%
    • Massive, life-threatening in 76%, often preceded by intermittent microhematuria or self-limited gross hematuria — "herald bleeds"
    • Intermittent microhematuria as the sole presentation in 9%[4]
    • Bleeding frequently occurs at the time of stent exchange — 42% (11/26) in one series[2]
  • Hemorrhagic shock — vasopressors (46%), transfusion (92%)[2]
  • Flank pain 42%[2]
  • Bladder tamponade from clot retention

The intermittent pattern is the diagnostic clue — the fistula may be temporarily sealed by clot or by the ureteral stent, leading to a deceptive period of resolution before catastrophic rebleeding. Any "herald bleed" in an at-risk patient should raise suspicion for AUF.[1][3][11]

Diagnosis​

No single test is highly sensitive; clinical suspicion is the most important factor. The diagnosis was made only at laparotomy in 36% of patients in one series.[3]

TestSensitivityNotes
Conventional angiography58–66%Most sensitive single test; allows simultaneous treatment[1][2][3]
Provocative angiographyHigherStent / guidewire manipulation during angiography to disrupt sealing clot; demonstrated the fistula in 100% when standard angiography was negative[12][13]
CT angiography33–36%Reasonable first imaging study; shows extravasation, pseudoaneurysm, hydronephrosis[2][6]
Retrograde / antegrade pyelographyVariableMay show contrast entering the vascular system[7][8]
UreteroscopyVariableDirect visualization; may provoke bleeding at the fistula site[9]
Intraoperative diagnosis—At laparotomy in 36% of cases[3]

Recommended workflow:[1][2][5][11]

  1. High clinical suspicion in any at-risk patient with hematuria.
  2. CT angiography as the first imaging study for availability and adjunctive findings, despite its modest direct-fistula sensitivity (~33%).[5]
  3. Interventional angiography promptly when AUF is suspected — both the most sensitive test and the immediate treatment modality. CT angiography may be skipped when suspicion is high.[2]
  4. Provocative angiography when standard angiography is non-diagnostic.[12][13]

Management​

AUF is a surgical / interventional emergency requiring a coordinated urology / vascular surgery / interventional radiology response.[1][2][14]

1. Endovascular treatment (preferred initial approach)​

Covered stent-graft placement is now first-line for most AUF, particularly in unstable or high-comorbidity patients.[1][2][8][14]

  • Technical success 91–100%[2][8][15]
  • Deployment of a covered stent-graft (Viabahn, iCast) across the fistula in the iliac artery, often with internal-iliac exclusion (coil or plug) to prevent retrograde flow[8][14]
  • Avoids laparotomy in a hostile pelvis

Endovascular complications:

  • Stent-graft infection — the most significant concern; 14–50% require reintervention. Particularly high in ileal-conduit patients given chronic colonization.[7][14]
  • Recurrent hematuria — 24–36% at 1–2 years; the hematuria recurrence-free rate at 2 years was only 40.6% in one long-term series.[15]
  • Stent thrombosis with lower-limb ischemia[16][17]
  • Stent migration — rare but dramatic; bladder migration has been reported[17]
  • Lower-extremity morbidity — ulceration, ischemia, amputation in 53% of patients in one series despite anticoagulation[16]

Long-term endovascular outcomes:[8][15]

  • Freedom from recurrent massive hematuria at 3 years: 76%
  • Primary patency at 3 years: 81%; secondary patency 92%
  • Freedom from stent-graft infection at 3 years: 100% in one series, but 14.3% infection rate in ileal-conduit patients[7][8]

2. Open surgical repair​

Indicated in specific scenarios:[8][14][18]

  • Preexisting vascular reconstruction (e.g., aortobifemoral graft) — endovascular stenting within a prior graft is technically challenging and infection-prone
  • Manifest infection — abscess, sepsis, infected endograft
  • Enteric contamination — concurrent enteric fistula
  • Failed endovascular treatment — recurrent bleeding or stent-graft infection after initial endovascular repair

Techniques:

  • Arterial ligation with extra-anatomic bypass (femoral-femoral crossover graft) — classic; avoids operating in the irradiated, scarred pelvis[6][12]
  • Direct arterial repair — primary repair or interposition graft; technically challenging in a hostile pelvis[8]
  • Arterial embolization with extra-anatomic bypass — percutaneous coil embolization of the common iliac followed by surgical fem-fem bypass; avoids laparotomy[12]
  • Ureteral management — nephrectomy, ureteral ligation, or PCN as needed[8][16]

Open-repair complications:[8][16]

  • Enterocutaneous fistula in 37.5% (3/8) in one series
  • Wound infection in 25%
  • Overall complication rate: 63% open vs. 36% endovascular

3. Hybrid approaches​

Initial endovascular stent-graft for hemorrhage control followed by planned open reconstruction is increasingly used.[18]

Mortality and Prognosis​

  • AUF-specific mortality has fallen from ~19% before 2000 to ~7% after 2000, paralleling adoption of endovascular stent-grafts.[1]
  • In-hospital mortality 7.7–10% in contemporary series.[2][16]
  • Overall mortality 47% at mean 15.5-month follow-up — driven by underlying advanced malignancy.[16]
  • 5-year survival 42% vs. 93% for the general population (p < 0.05).[8]
  • Recurrent AUF in 12.5–15% regardless of treatment modality.[2]
  • Patients with ureteral complications after aortoiliac reconstruction were 4.4× more likely to develop graft complications (p < 0.05).[10]

Part 2 — Renal Arteriovenous Fistula (AVF)​

Definition​

A renal AVF is an abnormal communication between a renal artery branch and a renal vein, bypassing the capillary bed. It is distinct from AUF in that the abnormality is intrarenal rather than ureteral.[19][20]

Classification​

Congenital arteriovenous malformations (AVMs):[19][20][21][22]

  • Rare (~20% of renal vascular malformations)
  • Three subtypes: cirsoid (multiple coiled vessels with a nidus — most common congenital type), angiomatous / cavernous (small, multiple communications resembling a hemangioma), and aneurysmal (single high-flow communication with an aneurysmal draining vein)[23]

Acquired (iatrogenic / traumatic) AVFs:[19]

  • Far more common than congenital AVMs
  • Single direct artery–vein communication without a nidus
  • Causes:
    • Percutaneous renal biopsy — most common; AVF detected in 14.4% of biopsies on routine Doppler, but 95% are asymptomatic[24]
    • PCNL and other percutaneous renal procedures[25]
    • Partial nephrectomy (open or laparoscopic)[25]
    • Penetrating or blunt trauma

Clinical Presentation​

Congenital AVMs:[20][21][23]

  • Hematuria — most common (gross 67%, microscopic 67%)
  • Refractory hypertension in 50% (DBP ≥ 90 mmHg despite ≥ 3 medications)
  • Flank pain 67%
  • High-output cardiac state in 25% with large fistulae
  • Flank bruit audible in some cases

Acquired (post-biopsy) AVFs:[24]

  • 95% asymptomatic — detected only on routine Doppler
  • 80% are < 1 cm
  • 46.6% close spontaneously within 30 days (range 3–151 days); larger AVFs (1–2 cm) take a mean of 52 days to close
  • Symptomatic forms can present with persistent hematuria, hypertension, or rarely high-output heart failure[20][26]

Diagnosis​

  • Doppler ultrasound — initial screening; high-velocity, low-resistance arterial flow with arterialized venous flow at the site. Routine post-biopsy Doppler is recommended.[24][27]
  • CT angiography — feeding artery, draining vein, nidus (if present); useful for treatment planning[22]
  • DSA renal arteriography — gold standard; demonstrates early venous filling and the fistula anatomy, and allows simultaneous embolization.[20][21]
  • MR angiography — alternative; useful for complex AVMs.[19]

Management​

Asymptomatic post-biopsy AVFs:

Conservative observation, with follow-up Doppler at 6 months to detect non-resolving lesions.[24][27][28]

Symptomatic or persistent AVFs — transarterial embolization (TAE):[23][25][29]

  • Technical success 100% in multiple series
  • Clinical success 88–100%
  • Embolic agents: coils (most common), n-butylcyanoacrylate glue, Amplatzer plugs, detachable balloons, or combinations
  • Renal parenchymal loss limited to < ~10–15%
  • Recurrence rare — none at mean 55-month follow-up in one series[23]
  • Postembolization syndrome (self-limited fever, pain) in 75%; no embolic-agent migration in most series

Surgery (nephrectomy or vessel ligation):[20]

  • Reserved for large, complex AVMs not amenable to embolization, failed embolization, or AVMs with associated renal arterial disease (aneurysm). Largely supplanted by embolization.

AUF vs. Renal AVF — Key Differences​

FeatureArterioureteral Fistula (AUF)Renal Arteriovenous Fistula (AVF)
CommunicationArtery (iliac) ↔ ureterRenal artery ↔ renal vein
Most common causeChronic ureteral stent + pelvic cancer / radiationPercutaneous renal biopsy
Incidence~3.5 / year (Netherlands)14.4% post-biopsy (mostly asymptomatic)
PresentationMassive hematuria, hemorrhagic shockUsually asymptomatic; hematuria, hypertension if symptomatic
Mortality7–19% (AUF-specific)Very low (~1%)
DiagnosisAngiography (~62% sensitivity)Doppler US → angiography
TreatmentEndovascular stent-graft or open surgeryTransarterial embolization
Spontaneous resolutionNo46.6% (post-biopsy)

Special Considerations​

AUF after aortoiliac vascular surgery​

Ureteral complications occur in approximately 1.4% of patients after aortoiliac reconstruction — hydronephrosis, ureteral leak, and AUF.[10] They are markers for graft complications: patients with ureteral complications had a 55% rate of graft complications (anastomotic aneurysm, thrombosis, infection, aortoenteric fistula) vs. 12% without ureteral complications (p < 0.05).[10]

AUF in ileal-conduit patients​

Chronic bacterial colonization of the conduit raises the risk of stent-graft infection after endovascular repair (14.3%), and infection is the leading indication for reintervention. Combined endovascular and endoureteral approaches showed similar outcomes to open surgery (UAF-related mortality 7.1% vs. 13.3%; complication rates 28.6% vs. 26.7%).[7]

Prevention​

No established prevention strategies, but the following are reasonable in at-risk patients:[1][2][6]

  • Minimize the duration of chronic ureteral stenting when possible
  • Consider softer, more flexible stent materials
  • Maintain a low threshold for angiography in any at-risk patient with even minor hematuria
  • Multidisciplinary discussion before stent exchanges in high-risk patients — 42% of AUF presentations occur during stent exchange.[2]

References​

1. Kamphorst K, Lock TMTW, van den Bergh RCN, et al. "Arterio-Ureteral Fistula: Systematic Review of 445 Patients." J Urol. 2022;207(1):35–43. doi:10.1097/JU.0000000000002241

2. Heers H, Netsch C, Wilhelm K, et al. "Diagnosis, Treatment, and Outcome of Arterioureteral Fistula: The Urologist's Perspective." J Endourol. 2018;32(3):245–251. doi:10.1089/end.2017.0819

3. van den Bergh RC, Moll FL, de Vries JP, Yeung KK, Lock TM. "Arterio-Ureteral Fistula: 11 New Cases of a Wolf in Sheep's Clothing." J Urol. 2008;179(2):578–581. doi:10.1016/j.juro.2007.09.087

4. Lock TMTW, Kamphorst K, van den Bergh RCN, et al. "Arterio-Ureteral Fistula: A Nationwide Cross-Sectional Questionnaire Analysis." World J Urol. 2022;40(3):831–839. doi:10.1007/s00345-021-03910-3

5. Ebata Y, Morisaki K, Matsubara Y, et al. "A Systematic Review of Management of Ureteroarterial Fistula." J Vasc Surg. 2022;76(5):1417–1423.e5. doi:10.1016/j.jvs.2022.05.015

6. Bergqvist D, Pärsson H, Sherif A. "Arterio-Ureteral Fistula — A Systematic Review." Eur J Vasc Endovasc Surg. 2001;22(3):191–196. doi:10.1053/ejvs.2001.1432

7. Matsunaga F, Dambaeva A, Ponsky LE, Kashyap VS, Tavri S. "Systematic Review of the Management of Ureteroarterial Fistulas After Ileal Conduit Urinary Diversion." AJR Am J Roentgenol. 2021;216(6):1452–1461. doi:10.2214/AJR.20.23132

8. Malgor RD, Oderich GS, Andrews JC, et al. "Evolution From Open Surgical to Endovascular Treatment of Ureteral-Iliac Artery Fistula." J Vasc Surg. 2012;55(4):1072–1080. doi:10.1016/j.jvs.2011.11.043

9. Blasco FJ, Saladié JM. "Ureteral Obstruction and Ureteral Fistulas After Aortofemoral or Aortoiliac Bypass Surgery." J Urol. 1991;145(2):237–242. doi:10.1016/s0022-5347(17)38302-7

10. Wright DJ, Ernst CB, Evans JR, et al. "Ureteral Complications and Aortoiliac Reconstruction." J Vasc Surg. 1990;11(1):29–35; discussion 35–37.

11. Pillai AK, Anderson ME, Reddick MA, Sutphin PD, Kalva SP. "Ureteroarterial Fistula: Diagnosis and Management." AJR Am J Roentgenol. 2015;204(5):W592–W598. doi:10.2214/AJR.14.13405

12. Vandersteen DR, Saxon RR, Fuchs E, et al. "Diagnosis and Management of Ureteroiliac Artery Fistula: Value of Provocative Arteriography Followed by Common Iliac Artery Embolization and Extraanatomic Arterial Bypass Grafting." J Urol. 1997;158(3 Pt 1):754–758.

13. Quillin SP, Darcy MD, Picus D. "Angiographic Evaluation and Therapy of Ureteroarterial Fistulas." AJR Am J Roentgenol. 1994;162(4):873–878. doi:10.2214/ajr.162.4.8141010

14. Sachsamanis G, Pfister K, Kasprzak PM, et al. "Midterm Results After Open Surgical and Endovascular Management of Arterioureteral Fistula." Ann Vasc Surg. 2021;73:280–289. doi:10.1016/j.avsg.2020.11.014

15. Okada T, Yamaguchi M, Muradi A, et al. "Long-Term Results of Endovascular Stent Graft Placement of Ureteroarterial Fistula." Cardiovasc Intervent Radiol. 2013;36(4):950–956. doi:10.1007/s00270-012-0534-6

16. Fox JA, Krambeck A, McPhail EF, Lightner D. "Ureteroarterial Fistula Treatment With Open Surgery Versus Endovascular Management: Long-Term Outcomes." J Urol. 2011;185(3):945–950. doi:10.1016/j.juro.2010.10.062

17. Liang NL, Avgerinos ED, Hager ES, Singh MJ. "Endovascular Repair of an Iliac Ureteroarterial Fistula With Late Stent Thrombosis and Migration Into the Bladder." Ann Vasc Surg. 2016;35:204.e5–7. doi:10.1016/j.avsg.2016.01.026

18. Hong SY, Noh M, Ko GY, et al. "Management Strategy for Ureteral-Iliac Artery Fistula." Ann Vasc Surg. 2016;36:22–27. doi:10.1016/j.avsg.2016.02.033

19. Cura M, Elmerhi F, Suri R, Bugnone A, Dalsaso T. "Vascular Malformations and Arteriovenous Fistulas of the Kidney." Acta Radiol. 2010;51(2):144–149. doi:10.3109/02841850903463646

20. Crotty KL, Orihuela E, Warren MM. "Recent Advances in the Diagnosis and Treatment of Renal Arteriovenous Malformations and Fistulas." J Urol. 1993;150(5 Pt 1):1355–1359. doi:10.1016/s0022-5347(17)35778-6

21. Cho KJ, Stanley JC. "Non-Neoplastic Congenital and Acquired Renal Arteriovenous Malformations and Fistulas." Radiology. 1978;129(2):333–343. doi:10.1148/129.2.333

22. Cai J, Ding L, Xie Y, Wang Y. "Congenital Renal Arteriovenous Malformation With Cirsoid and Cavernosal-Type Characteristics: A Case Report." J Int Med Res. 2021;49(5):3000605211016381. doi:10.1177/03000605211016381

23. Nassiri N, Dudiy Y, Carroccio A, Rosen RJ. "Transarterial Treatment of Congenital Renal Arteriovenous Fistulas." J Vasc Surg. 2013;58(5):1310–1315. doi:10.1016/j.jvs.2013.05.010

24. Sosa-Barrios RH, Burguera V, Rodriguez-Mendiola N, et al. "Arteriovenous Fistulae After Renal Biopsy: Diagnosis and Outcomes Using Doppler Ultrasound Assessment." BMC Nephrol. 2017;18(1):365. doi:10.1186/s12882-017-0786-0

25. Guo H, Wang C, Yang M, et al. "Management of Iatrogenic Renal Arteriovenous Fistula and Renal Arterial Pseudoaneurysm by Transarterial Embolization: A Single Center Analysis and Outcomes." Medicine (Baltimore). 2017;96(40):e8187. doi:10.1097/MD.0000000000008187

26. Bilge I, Rozanes I, Acunas B, et al. "Endovascular Treatment of Arteriovenous Fistulas Complicating Percutaneous Renal Biopsy in Three Paediatric Cases." Nephrol Dial Transplant. 1999;14(11):2726–2730. doi:10.1093/ndt/14.11.2726

27. Yang CY, Lai MY, Lu CL, et al. "Timing of Doppler Examination for the Detection of Arteriovenous Fistula After Percutaneous Renal Biopsy." J Clin Ultrasound. 2008;36(6):377–380. doi:10.1002/jcu.20459

28. Floege J, Amann K. "Primary Glomerulonephritides." Lancet. 2016;387(10032):2036–2048. doi:10.1016/S0140-6736(16)00272-5

29. Peluso N, Donato F, Sposato F, et al. "Safety and Efficacy of Endovascular Treatment for Congenital Renal Arteriovenous Fistulas." Ann Vasc Surg. 2025;114:260–269. doi:10.1016/j.avsg.2025.01.045