Renal artery pseudoaneurysm after partial nephrectomy

Dear Editor,

Nephron-sparing surgery has emerged as an excellent option for the management of small renal cortical tumors. Renal artery pseudoaneurysm is a rare complication of partial nephrectomy and a limited number of reports describing the presentation and management of this situation have been published so far¹. We report two cases of renal artery pseudoaneurysm occurred after elective nephron-sparing surgery.

The first one is refered to a 35-year-old woman who underwent an open left partial nephrectomy. Complete intraoperative hemostasis was achieved using interrupted figure-of-eight 4-0 chromic sutures at sites of parenchymal bleeding. Twelve days postoperatively, the patient reported gross hematuria and intermittent left flank pain. Renal arteriography was performed and revealed a left renal artery pseudoaneurysm with active extravasation. Coil embolization was performed with complete resolution of her hematuria.

The second case to a 59-year-old man underwent retroperitoneal laparoscopic partial nephrectomy. The defect was closed with 0 glycolide/lactide suture in a horizontal mattress fashion over an oxidized cellulose bolster. On postoperative day 3, the patient reported left flank discomfort and gross hematuria. CT scan revealed multiple pseudoaneurysms and the patient underwent selective arteriography confirming the diagnosis. Percutaneous selective coil angioembolization was successfully performed.

Hemorrhage is the most common complication of partial nephrectomy. However, less commonly, hemorrhage can also occur in the context of a pseudoaneurysm with reported rates of 0.4%-1.4%^2,3. Currently, only 25 reported cases are available in the partial nephrectomy literature, with 11 reported after laparoscopic partial nephrectomy and the first one being described in 1973¹.

A pseudoaneurysm during partial nephrectomy procedure is thought to be formed from inadvertent vessel injury or from a suture placed through a vessel during the approximation of the renal parenchyma. After the initial renal injury, hypotension, coagulation and pressure from the surrounding tissue (vascular adventitia, renal parenchyma and Gerota’s fascia) results in temporary cessation of the bleeding. Degradation of the clot and surrounding necrotic tissue results in recanalization between the intravascular and extravascular space and, subsequently, the formation of a pseudoaneurysm. With restoration of normal blood flow, this pseudoaneurysm can grow and eventually become unstable with erosion into the surrounding pelvicaliceal system or the surrounding perinephric tissue⁴. Angiography has been shown to be the gold standard for the diagnosis of renal artery pseudoaneurysm. However, if the patient is hemodynamically stable, non-invasive tests such as contrast medium-enhanced CT and magnetic resonance angiography should be performed. Percutaneous selective coil angioembolization is a safe and efficient technique for the management of the patients with this delayed form of hemorrhage, providing excellent results with maximal renal preservation.

In our opinion, post-partial nephrectomy rates of pseudoaneurysm should be well analyzed by large series studies, since the rarity of this serious and insidious complication is debated.