Transplant Reports : Open Access
Open Access

Vascular complications; Arterial bleeding; Transplant recipient; Transplant surgery; Infection; Fungal infection; Vascular injury; Graft dysfunction; Surgical complications; Imaging techniques; Angiography; Vascular intervention; Embolization; Reoperation; Immunosuppression

Introduction

Since the first kidney transplant in 1954, significant advancements in surgical techniques and immunosuppressive therapies have made kidney transplantation the primary treatment for individuals with end-stage renal disease. However, approximately 10% of kidney transplant recipients experience complications. Medical complications include acute tubular necrosis, acute or chronic allograft rejection, and nephropathy resulting from immunosuppressive medications. Urologic complications encompass ureteral obstruction, urinoma, abscess, and lymphocele formation. Vascular complications, which can lead to graft loss, include renal artery thrombosis or stenosis, renal vein thrombosis, and other less common issues such as aneurysm, hematoma, and arteriovenous fistula. Pseudo-aneurysms are rare complications following kidney transplantation, often occurring at anastomotic sites or within the renal parenchyma, typically resulting from infection or technical errors. Although mycotic aneurysms account for a small percentage of cases after kidney transplantation, rupture of an anastomotic pseudo-aneurysm can lead to severe bleeding and death, necessitating emergency intervention such as graft nephrectomy. Moreover, the treatment of mycotic pseudo-aneurysms after kidney transplantation often entails high morbidity and graft failure. Literature on this condition is limited, with few studies or isolated case reports available. There remains debate regarding the etiology, prevalence, treatment, and prognosis of mycotic pseudoaneurysms after kidney transplantation, underscoring the importance of early diagnosis for successful therapy. In our report, we describe two cases of extrarenal mycotic pseudo-aneurysm successfully treated through early intervention, leading to graft preservation, improved outcomes, and patient survival. This report aims to highlight the successful management of these cases and contribute to the existing knowledge on this rare complication [1,2].

Material and Methods

Case 1:

Case 1 was a 54-year-old man with end-stage renal disease due to sarcoidosis and scleroderma. Eight days after initiating peritoneal dialysis, he underwent deceased-donor kidney transplantation, placing the left kidney into the right iliac fossa. The surgical procedure, including an end-to-side anastomosis of the graft vessels with the recipient's external iliac artery and vein, proceeded without complications. The surgical approach involved an extraperitoneal exposure through a Gibson incision. Cold ischemia time was 16.1 hours, with warm ischemia time of 32 minutes. Immediate graft function was indicated by urine output and postoperative serum creatinine levels. Immunosuppressive therapy consisted of tacrolimus, mycophenolate mofetil, prednisone, and basiliximab. Antibiotic prophylaxis was administered for 48 hours post-transplantation (vancomycin 1 g/day, cefotaxime 2 g/day). Shortly after surgery, the patient developed fever, and blood cultures revealed Serratia marcescens infection, which was treated with intravenous meropenem [3]. On the eighth day posttransplantation, the patient experienced hemorrhagic shock due to rupture of the arterial anastomosis. Surgical intervention involved in situ reconstruction of the arterial anastomosis. The patient required hemodialysis for 20 days, with delayed but ultimately effective diuresis recovery. Sixty-two days post-transplantation, a laparotomy revealed a pseudo-aneurysm at the right external iliac artery and proximal portion of the graft artery. The pseudo-aneurysm was meticulously dissected, and vascular control was established proximally and distally. The right saphenous vein was prepared for use as a vascular graft, and a bypass was performed from the common iliac artery to the distal graft artery. Complete resection of the pseudo-aneurysm was performed, followed by end-to-end reconstruction of the external iliac artery [4].

Case 2:

Case 2 was a 48-year-old woman with hereditary nephropathy who received a deceased-donor left kidney transplant into the right iliac fossa via a Gibson incision and extraperitoneal exposure. Cold ischemia time was 22.1 hours, with warm ischemia time of 44 minutes. Immunosuppressive therapy included tacrolimus, mycophenolate mofetil, and steroids. She received antithymocyte globulin for postoperative steroid-resistant rejection, leading to improvement in her creatinine levels. Pathological examination of the graft biopsy revealed Citrobacter koseri infection, treated with systemic meropenem [5]. Five months post-transplantation, the patient developed non-disabling intermittent claudication in the right lower limb and experienced an acute rise in serum creatinine levels. No signs of systemic infection were noted. Color-coded Doppler ultrasonography revealed enlargement of the arterial anastomosis and occlusion of the right external iliac artery. CT angiography confirmed ischemia of the upper pole of the graft, thrombosis within the renal artery, a pseudo-aneurysm at the arterial anastomosis (measuring 30.9 × 18.2 mm), and occlusion of the right external iliac artery [6].

Discussion

These two cases exhibited mycotic pseudo-aneurysms following kidney transplantation, confirmed through imaging studies and culture of the resected pseudo-aneurysm. In Case 2, the claudication was not disabling, and limb revascularization was unnecessary. Vascular complications are a significant cause of kidney allograft failure, occurring in 3-15% of kidney transplants, more frequently after deceased-donor than living-donor transplantation, and with allografts featuring multiple vessels [7]. Fungal infections can affect 5-20% of all solid organ transplants and 5% of kidney transplants. These infections may stem from donor tissue or, more commonly, from exogenous sources during procurement and transplantation, such as contaminated preservation fluid. Candida species infections typically manifest within two months post-transplantation and can lead to arterial complications, major bleeding, sepsis, and mortality. Notably, fungal arteritis associated with Candida from preservation fluid has led to significant complications, including graft loss and death. Early detection of fungal contamination in preservation fluid may prompt preemptive nephrectomy, although conservative management may also be viable and compatible with patient survival [8].

Among fungal vascular complications after kidney transplantation, extrarenal mycotic pseudo-aneurysms are associated with high morbidity and mortality, but optimal therapeutic approaches are debated. Regardless of the pathogen, most mycotic pseudo-aneurysms after kidney transplantation involve the anastomosis between the recipient renal artery and the donor external iliac artery. These pseudo-aneurysms may be asymptomatic and incidentally detected during routine follow-up or present with fever, anemia, abdominal pain, pulsatile mass, or hemorrhagic shock. Imaging modalities like color-coded Doppler ultrasonography aid in diagnosis, often revealing inflow within the pseudo-aneurysm. Treatment guidelines for mycotic pseudo-aneurysms after kidney transplantation are lacking, and options are controversial [9,10].

Conclusion

In our experience, early detection and intervention are crucial for kidney allograft preservation and patient survival. Literature review indicates that many cases of post-transplantation mycotic pseudoaneurysms undergo allograft nephrectomy due to chronic rejection, graft dysfunction, and infection. Treatment options include surgical repair, endovascular intervention, and percutaneous ultrasoundguided thrombin injection. Successful treatment involves radical debridement of infected tissue, long-term antifungal therapy, and delicate vascular reconstruction using autologous or allogeneic material to prevent graft loss. In summary, the treatment of posttransplantation mycotic pseudo-aneurysms involves excision of infected tissue, arterial reconstruction with autologous tissue, and long-term antifungal therapy, resulting in successful kidney allograft preservation. Transplant nephrectomy may not always be necessary, and treatment decisions should be individualized.

Acknowledgments

None

Conflict of interest

None

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