Open repair of infrarenal abdominal aortic aneurysm in a renal transplant recipient using extra-anatomic bypass: a case report

Abstract

Introduction and Importance:

Abdominal aortic aneurysm (AAA) is a common vascular pathology in elderly males and carries a substantial risk of rupture when large or symptomatic. The management of AAA in renal transplant recipients is particularly challenging due to the vulnerability of the transplanted kidney to ischemic injury during aortic cross-clamping and the frequent presence of multiple comorbidities.

Presentation of Case:

We report the case of a 67-year-old male who presented with chronic low back pain radiating to the hips for 3 months, accompanied by weight loss and intermittent constipation. His medical history was significant for hypertension, chronic kidney disease, a previous cerebrovascular accident, coronary artery disease treated with stent placement, and a left renal transplant performed 6 years earlier. Laboratory investigations were largely unremarkable, except for elevated creatinine and prolonged prothrombin time. Contrast-enhanced magnetic resonance imaging revealed a large 7-cm infrarenal abdominal aortic aneurysm, with the transplanted kidney supplied by the left external iliac artery. Given the aneurysm size, symptoms, and anatomical considerations, surgical intervention was indicated.

Clinical Discussion:

AAA repair in renal transplant recipients requires meticulous preoperative planning to prevent allograft ischemia and postoperative renal dysfunction. Although endovascular aneurysm repair may be considered in selected cases, anatomical constraints and concerns regarding contrast exposure may limit its applicability.

Conclusion:

This case demonstrates that open AAA repair with extra-anatomic bypass can be successfully performed in renal transplant recipients, providing effective aneurysm treatment while preserving allograft function. A multidisciplinary, individualized approach remains essential for optimizing outcomes in this high-risk population.

Introduction

Abdominal aortic aneurysm (AAA) is one of the most common forms of arterial aneurysms^[1,2^]. The management of AAA in kidney transplant recipients poses a rare yet critical vascular challenge, accounting for only about 1% of AAA repair cases in some series^[1^]. The significance of this condition is amplified by improved long-term graft survival and the high prevalence of cardiovascular diseases in this patient population, thereby increasing the likelihood of encountering this complex comorbidity^[1–3^].

HIGHLIGHTS

• The management of an abdominal aortic aneurysm in kidney transplant recipients is a rare clinical scenario; yet, it presents a critical challenge.

• While endovascular repair offers the advantage of shorter ischemia time, it is often complicated by anatomical and physiological factors common in transplant patients, such as challenging iliac artery anatomy, contrast allergies, and the risk of further kidney damage from contrast dye.

• To overcome the key risk of kidney ischemia, surgeons can employ temporary extra-anatomic shunts during the procedure to maintain continuous blood flow to the transplanted organ.

The surgical necessity is evident but fraught with difficulties. The viability of the transplanted kidney depends on a solitary, distal arterial supply from the iliac system, which lacks robust collateral networks^[1,3,4^]. This anatomical reality renders the transplanted kidney highly susceptible to ischemic injury during surgery. Compounding this risk is evidence suggesting that AAA behavior may be more aggressive in transplant recipients, with potentially accelerated expansion rates linked to immunomodulatory therapy^[1^].

The choice of repair strategy requires careful and meticulous consideration. While endovascular aortic repair (EVAR) reduces the duration of ischemia, it may be contraindicated or considered high-risk due to factors common in this cohort: iliac artery tortuosity and calcification preventing device delivery^[1,3^], a history of severe iodinated contrast allergy^[1,2^], or ongoing concerns about contrast-induced nephropathy in a kidney with pre-existing impaired function. When pursuing EVAR, it necessitates precise adjunctive techniques – such as the use of low-profile sheaths, accurate stent-graft length measurement, and CO₂ angiography – to protect the transplanted kidney^[2,4^].

Consequently, open surgical repair remains a vital option. Techniques such as temporary extra-anatomic shunts (axillo-iliac or brachiofemoral) have been successfully employed to maintain renal perfusion during surgery, demonstrating effectiveness in preserving renal function with satisfactory postoperative outcomes^[1,3,4^].

In this context, we present a case report of open AAA repair in a kidney transplant recipient, utilizing a temporary axillofemoral shunt. This report aims to detail this surgical experience and contribute to the ongoing discussion regarding optimal strategies for managing AAA in this high-risk patient population, where preserving the function of the transplanted kidney is of paramount importance.

Case presentation

A 67-year-old male patient was admitted to the hospital with complaints of low back pain radiating to the hips for 3 months, accompanied by a history of weight loss and intermittent constipation. His medical history includes a left-sided cerebrovascular accident 13 years ago, hypertension, and chronic kidney disease for the past 3 years. His surgical history includes an exploratory laparotomy due to a gunshot wound and a pseudoaneurysm of the right femoral artery 3 years ago following a cardiac catheterization with the placement of three stents, as well as a left kidney transplant 6 years ago.

The patient is on antihypertensive medications, anticoagulants, and lipid-lowering agents. All laboratory tests were normal except for creatinine, which was 2.1, and prothrombin time, which was 61.

Magnetic resonance imaging (MRI) with contrast revealed an AAA measuring 7 cm in maximum diameter, located infrarenally, with a transplanted kidney situated on the left external iliac artery (Figs. 1, 2, and 3).

Figure 1.

Aortic aneurysm and transplanted kidney on the left external iliac artery in three-dimensional view.

Figure 2.

Aortic aneurysm and transplanted kidney on the left external iliac artery.

Figure 3.

Aortic aneurysm and transplanted kidney on the left external iliac artery.

Surgical repair of the AAA was performed using a Dacron tube graft with proximal and distal end-to-end anastomoses (Fig. 4). The transplanted kidney was preserved by using a temporary extra-anatomic vascular bypass from the left axillary artery to the left femoral artery. Following the aortic aneurysm repair and removal of this temporary axillofemoral bypass, both the axillary and femoral arteries were closed using a vein patch harvested from the great saphenous vein. The ultrasound showed triphasic signals along the entire arterial axis of the lower extremities after surgery, and the laboratory tests for the kidneys were normal after surgery.

Figure 4.

An abdominal aortic aneurysm was repaired via interposition of a Dacron tube graft, utilizing end-to-end anastomoses proximally and distally.

Discussion

AAA is a relatively common vascular condition in older adults, with a well-documented predilection for elderly males. Population-based studies estimate the prevalence of AAA to range between 4% and 8% in men over the age of 65 years, compared with less than 2% in women, reflecting a strong sex disparity. Age, male sex, hypertension, smoking, and atherosclerotic cardiovascular disease are established risk factors, many of which were present in this patient^[4,5^]. Although smoking is considered the most significant modifiable risk factor, hypertension and underlying vascular disease also contribute substantially to aneurysm development and progression^[5,6^].

AAA most commonly occurs in the infrarenal segment of the abdominal aorta, accounting for approximately 85–90% of cases. The risk of rupture increases markedly with aneurysm diameter, particularly when exceeding 5.5 cm, making timely surgical intervention critical. Large aneurysms, such as the 7-cm aneurysm observed in this case, carry a significantly elevated annual rupture risk, estimated to exceed 20%, underscoring the urgency of repair regardless of symptom severity^[3,6,7^].

The coexistence of AAA in renal transplant recipients is uncommon but clinically significant. The increasing longevity of transplant recipients and the high prevalence of cardiovascular risk factors in this population may predispose them to accelerated atherosclerosis and aneurysm formation. However, the exact incidence of AAA in renal transplant patients remains poorly defined, with available data limited to case reports and small case series^[6,8^].

AAA is often clinically silent and frequently detected incidentally; however, symptomatic presentations may occur, particularly in large or expanding aneurysms. Chronic low back pain radiating to the hips, as observed in this patient, is a recognized but nonspecific manifestation of infrarenal AAA and may result from aneurysmal expansion with pressure on adjacent retroperitoneal structures. Associated constitutional symptoms, such as weight loss and gastrointestinal complaints, including constipation, have been reported in large aneurysms due to mass effect on surrounding organs^[7,8^].

The diagnosis of AAA relies primarily on imaging studies. Ultrasound is widely accepted as the first-line modality for screening and surveillance due to its high sensitivity and specificity, cost-effectiveness, and lack of radiation exposure. However, cross-sectional imaging is essential for preoperative planning^[8–10^]. Computed tomography angiography is considered the gold standard for detailed anatomical assessment, including aneurysm size, extent, involvement of branch vessels, and suitability for endovascular or open repair. In this case, contrast-enhanced MRI provided comprehensive anatomical detail while avoiding iodinated contrast, which is particularly relevant in patients with chronic kidney disease and renal transplantation^[5,9^].

Current clinical guidelines recommend elective repair of infrarenal AAA in symptomatic patients or when the aneurysm diameter exceeds 5.5 cm in men, provided that the operative risk is acceptable. Both open surgical repair and EVAR are established treatment options, with selection guided by anatomical suitability, patient comorbidities, and institutional expertise^[8,10,11^].

In renal transplant recipients, AAA repair presents unique technical challenges. Aortic cross-clamping during open repair can compromise perfusion to the transplanted kidney, which typically lacks collateral circulation and is particularly vulnerable to ischemic injury. Although EVAR may theoretically reduce ischemic risk by avoiding prolonged aortic clamping, its feasibility is often limited by unfavorable anatomy, prior surgical interventions, or the proximity of the transplant renal artery to the iliac landing zones. Additionally, the need for iodinated contrast during EVAR raises concerns regarding contrast-induced nephropathy in patients with impaired renal function^[3,5,7^].

Open surgical repair with renal protection strategies remains a widely reported and effective approach in complex cases. Various methods have been described in the literature to preserve allograft perfusion, including temporary intraluminal shunts, cold renal perfusion, extracorporeal circulation, and extra-anatomic bypass techniques. The axillofemoral bypass employed in this case represents a well-established renal protection strategy that allows continuous perfusion of the transplanted kidney during aortic reconstruction while minimizing ischemic time^[2,4,6,7^].

The favorable postoperative outcome observed – evidenced by preserved renal function and triphasic distal arterial flow – supports the effectiveness of this approach. Careful perioperative anticoagulation management, vigilant monitoring of renal parameters, and postoperative vascular assessment are essential components of successful outcomes in this high-risk population^[1,4,5^].

Overall, this case illustrates that open AAA repair with extra-anatomic bypass remains a safe and viable option in renal transplant recipients with complex anatomy or contraindications to EVAR. Individualized treatment planning and a multidisciplinary approach are paramount to balancing aneurysm-related mortality risk against the preservation of allograft function^[1,8–10^].

Conclusion

This case highlights the complexity of managing AAA in patients with a functioning renal transplant and multiple comorbidities. Large infrarenal AAAs may present with nonspecific symptoms, emphasizing the importance of a high index of suspicion and appropriate imaging for timely diagnosis. In renal transplant recipients, careful preoperative assessment and individualized surgical planning are essential to minimize the risk of graft ischemia and postoperative renal dysfunction. Open surgical repair with an extra-anatomic axillofemoral bypass provided effective aneurysm exclusion while preserving renal allograft perfusion, resulting in a favorable clinical and functional outcome. As the population of elderly transplant recipients continues to grow, this case underscores the need for multidisciplinary management and tailored vascular strategies to achieve optimal patient and graft survival.

Ethical approval

Ethical approval is not required for case reports deemed not to constitute research at our institution (Damascus University).

Consent

Written informed consent was obtained from the patient.

Sources of funding

None declared.

Author contributions

G.A., M.A., M.S., H.H., and A.A. wrote a part of the manuscript. All authors approved the final manuscript.

Conflicts of interest disclosure

The authors declare no conflicts of interest.

Research registration unique identification number (UIN)

Not applicable.

Guarantor

Mouhammed Sleiay.

Provenance and peer review

This work was not commissioned and has been externally peer-reviewed.

Data availability statement

Not applicable.

Methods

The work has been reported as per the SCARE criteria^[12^].