血管內治療在腎臟移植病患併發感染性假性動脈瘤：個案報告

黎赫^1,2、江佩璋¹、周孟翰¹、丁慧恭¹、卓育慶¹、陳進利¹、楊明昕¹、高建璋¹、

曹智惟¹、蒙恩¹、吳勝堂¹、查岱龍¹、孫光煥¹、于大雄¹

¹國防醫學院三軍總醫院外科部泌尿外科；²國軍高雄總醫院岡山分院外科部泌尿外科

Endovascular treatment for mycotic pseudoaneurysm in a renal transplant patient: A case report

Ho Li^1,2, Pei-Jhang Chiang¹, Meng-Han Chou¹, Hui-Kung Ting¹, Yu-Chin Jhuo¹,

Chin-Li Chen¹, Ming-Hsin Yang¹, Chien-Chang Kao¹, Chih-Wei Tsao¹, En Meng¹,

Sheng‐Tang Wu¹, Tai-Lung Cha¹, Guang-Huan Sun¹, Dah-Shyong Yu¹

¹Division of Urology, Department of Surgery, Tri‐Service General Hospital, National Defense Medical Center, Taipei, Taiwan

²Division of Urology, Department of Surgery, Gangshan Branch of Kaohsiung Armed Forces General Hospital, Kaohsiung, Taiwan

Introduction: Approximately 6% to 30% of patients experience vascular complications following kidney transplantation, which may include renal artery stenosis, arteriovenous thrombosis, arteriovenous fistula, and pseudoaneurysm. Mycotic pseudoaneurysms occur in fewer than 1% of kidney transplant recipients but can pose a significant risk to both the transplanted kidney and the patient's life. Clinical symptoms of mycotic pseudoaneurysms can range from asymptomatic presentations to fever, pain in the iliac fossa, renal function impairment, and shock. Common pathogens associated with these infections include Candida albicans, Pseudomonas aeruginosa, and Klebsiella pneumoniae. Diagnostic methods include blood cultures, ultrasound, and computed tomography. Antibiotic treatment is essential in cases of infection. Furthermore, therapeutic options for managing pseudoaneurysms include aneurysmectomy, proximal and distal ligation of the arterial trunk, medical management, and percutaneous embolization. Here, we reported a case of pseudoaneurysm after kidney transplantation, who successfully preserved allograft after received femoral-femoral bypass and percutaneous transluminal angioplasty (PTA) with stenting, and coil embolization of the pseudoaneurysm.

Case presentation: A 56-year-old male patient with end-stage renal disease began hemodialysis in 2020 and underwent cadaveric kidney transplantation (right kidney to left iliac fossa) on December 5, 2023. Post-surgery, the patient was hospitalized multiple times due to urinary tract infections and bacteremia. Urine cultures revealed the presence of Enterococcus faecium, Proteus mirabilis, and coagulase-negative Staphylococcus, while blood cultures consistently showed Pseudomonas aeruginosa. Antibiotic treatments, including ceftazidime, piperacillin/tazobactam, and fosfomycin, were administered at various time points. In April, 2024, a renal ultrasound detected a suspected pseudoaneurysm in the left iliac artery, which was subsequently confirmed by angiography. Cardiovascular surgeon then performed femoral-femoral bypass using an 8 mm Geotex polytetrafluoroethylene (PTFE) graft, percutaneous transluminal angioplasty (PTA) with stenting of the renal artery of the graft kidney and the left external iliac artery, and coil embolization of the left pseudoaneurysm and left common iliac artery. Color Doppler ultrasonography performed after surgery revealed minimal residual flow within the aneurysm. For the transplanted kidney, the interlobular artery exhibited a resistive index of 0.63 and a peak systolic velocity of 23.6 cm/second. The renal artery showed a resistive index of 0.72 and a peak systolic velocity of 57.1 cm/second. Both arteries displayed normal waveforms.

Discussion: Pseudoaneurysms can be classified as either intrarenal or extrarenal. Extrarenal pseudoaneurysms may arise from infectious or non-infectious causes. Infectious causes include fungal infections, with Candida albicans being the most common organism responsible for mycotic pseudoaneurysms. Other fungal species, such as Aspergillus, can also contribute to this condition. Bacterial infections, particularly those caused by Pseudomonas aeruginosa and Enterococcus faecalis, can lead to infectious pseudoaneurysms. Kidney transplant patients are particularly vulnerable to opportunistic infections due to the use of immunosuppressive medications. Extrarenal pseudoaneurysms with a diameter greater than 2.5 cm are at a high risk of rupture and typically require surgical intervention, while those smaller than 2 cm are usually monitored. Therapeutic options for large or high-risk extrarenal pseudoaneurysms include allograft nephrectomy, conventional open repair (which involves allograft removal, creation of new vascular anastomoses, and repair of the previous site with patch angioplasty), endovascular stenting or coiling, and/or ultrasound-guided percutaneous thrombin injection. In our case, endovascular stenting and coiling were employed to treat a pseudoaneurysm, and a femoral-femoral bypass was established to ensure adequate blood supply to the left lower extremity. Post-operative color Doppler ultrasonography revealed minimal residual flow in the aneurysm. The transplanted kidney exhibited good intrarenal perfusion, and there was no evidence of renal artery stenosis.

Conclusion: For kidney transplant patients who develop urinary tract infections and bacteremia, it is essential to closely monitor for mycotic pseudoaneurysms and to intervene promptly in order to reduce the risk of transplant failure and potentially life-threatening complications.