Renal artery pseudoaneurysms post percutaneous nephrolithotomy: A case report.

Percutaneous Nephrolithotomy (PCNL) is a standard, safe and efficient method for removing large renal calculi. This pathology is associated with a risk of life-threatening Iatrogenic Renal Vascular Injuries, such as pseudoaneurysm (1%-3%). We report the case of a 49 old year male patient with Hematuria post PCNL for renal calculi. Computed tomography renal angiography was indicated which showed a pseudoaneurysm in the lower pole of the left kidney confirmed by digital subtraction angiography. Super selective endovascular embolization was successfully performed with conservation of the left-over vascularization of the kidney. No postoperative complications were seen. We aimed to report this case and to review the literature regarding endovascular management of kidney pseudoaneurysms after PCNL.

Introduction

Renal artery pseudoaneurysm (RAP) is a rare renal vascular abnormality that may occur as a complication after percutaneous nephrolithotomy. It can cause gross hematuria or even life-threatening hemorrhage, demanding efficient treatment by transarterial embolization. Super selective transarterial embolization procedure is a minimally invasive, safe, and efficient procedure in the management of arterial hemorrhage due to PCNL.

Case report

A 49-year-old male was addressed to the Department of Radiology for computed tomography of abdomen/pelvis for intermittent hematuria happening 5 days after a standard PCNL of an inferior caliceal stone in the left kidney.

It shows a cystic hyperdense lesion approximately 2 × 3 cm in size in the lower pole of the left kidney highly suggestive of pseudoaneurysm (Fig. 1). Renal angiography was performed, which revealed that the pseudoaneurysm arises from the posterior segmental branch of the left renal (Fig. 1). No arteriovenous fistula was found. All other abdominopelvic organs added to the aorta and the other arteries were normal. No abnormalities were seen in clinical examination. Her blood pressure was 110/80 mm Hg and his laboratory tests were relatively within normal.

Fig. 1

Enhanced computed tomography axial image showing the left lower renal pole pseudoaneurysm (Red arrow) at the percutaneous nephrolithotomy “track” (white arrow).

Digital subtraction angiography was indicated with Selective renal angiography, through left retrograde femoral access, using a 5F vascular sheath and a 5F cobra catheter. A coaxial microcatheter was advanced, allowing super-selective access to the feeding artery, confirming a pseudoaneurysm arising from the posterior segmental branch of the left renal artery. To perform embolization embolic agents were injected. Exclusion of the pseudoaneurysm was successfully reached with conservation of the remaining vascularization of the left kidney and no evident parenchymal loss (Fig. 2, Fig. 3). The total procedure time was 1 hour. No immediate complications were noticed and hematuria disappeared 4 days after. The patient stayed asymptomatic, and no recurrence was found at two months of CT follow-up.

Fig. 2

Digital subtraction angiography before embolization, with the 5F cobra catheter (Thin arrow) selectively positioned at the left renal artery, showing the pseudoaneurysm (Red arrow).

Fig. 3

Digital subtraction angiography after embolization, that shows Onyx (red arrow) at the distal extremity of the feeding artery.

Discussion

Renal artery pseudoaneurysm (RAP) is an unusual condition that may occur as a complication associated with percutaneous nephrolithotomy. Hematuria is the most common symptom associated with RAP [1]. It results from trauma to either the anterior or posterior segmental arteries, more than the smaller peripheral interlobular arteries, which are bordered by dense parenchyma and therefore safe to tamponade with the nephrostomy tube [2]. This is observed in our case as the lesion arises from the segmental arteries.

Noninvasive diagnostic modalities, mainly CT angiography, should be indicated in the initial examination. It has the advantage to show the entire urinary tract and it is the modality of choice for follow-up. RAP is best seen on the arterial phase, as it appears as a focal lesion with a high density similar to that of the adjacent arterial vessels. However, Digital subtraction angiography remains the gold standard when PCNL complicates with bleeding that cannot be managed with conservative treatment. It should be performed both as a diagnostic and therapeutic method [3].

The most common angiographic results associated with hemorrhage after PCNL are arterial pseudoaneurysms and/or AFV [4].

Angiographic embolization is the treatment of choice for RAP due to its minimally invasive and absence of parenchymal loss [5].

It starts with a renal angiogram through a transfemoral approach. Selective embolization of renal artery branches can be achieved by using microcatheters inserted coaxially in a guidewire minimizing loss of viable tissue. Different embolic agents are accessible to treat vascular injuries of PCNL counting coils, particulate agents, and liquid agents. They can be used either alone or combined [6]. The choice should be based on the patient's vascular anatomy and the pathologic process.

In our patient, we used liquid agents (eg, Onyx) due to their availability in our institution.

Many case series and reports have shown that coil embolization is an effective method for treating renal pseudoaneurysms post PCNL with high success rates. Therefore, Onyx can be administrated in a slower, accurate, and more commanded way than other embolic agents, reducing remarkably the risk of ischemic complications [7,8]. Nevertheless, the purpose is to ensure adequate occlusion.

In conclusion, Superselective endovascular embolization is a relevant technic that allows early diagnosis and treatment of significant post-PCNL pseudoaneurysms and should be considered as a first-line management tool.

PCNL is currently the modality of choice for removal of large renal calculi.

Renal artery pseudoaneurysm (RAP) is a rare renal vascular injury that occurs after PCNL.

Super selective endovascular embolization is an effective, minimally invasive and relatively easy technic, it should be considered as a first-line in the management of renal pseudoaneurysms post PCNL.

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