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Year : 2021  |  Volume : 8  |  Issue : 4  |  Page : 378-380

Thrombosed abdominal aortic aneurysm with horseshoe kidney presenting with acute limb ischemia

1 Department of General Surgery, Selayang Hospital, Selangor, Malaysia
2 Department of Surgery, Vascular Unit, Hospital Kuala Lumpur, Kuala Lumpur, Malaysia

Date of Submission26-Feb-2021
Date of Acceptance18-May-2021
Date of Web Publication9-Dec-2021

Correspondence Address:
Muhammad Aizat Tamlikha
Department of General Surgery, Selayang Hospital, Selangor
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Source of Support: None, Conflict of Interest: None

DOI: 10.4103/ijves.ijves_22_21

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Acute thrombosis of an abdominal aortic aneurysm with a horseshoe kidney (HSK) is a very rare phenomenon. This anatomical anomaly poses a challenge for the surgeon which requires prompt treatment. We present a case report of an elderly man who presented with a threatened acute left leg ischemia and a pulsatile abdominal mass. Computed tomography revealed a huge fusiform infrarenal aortic aneurysm extending to the left iliac artery with thrombotic occlusion and a HSK. He underwent emergency transabdominal laparotomy and aneurysectomy with inlay bifurcated graft repair. The renal isthmus was preserved and left accessory renal artery was reimplanted onto the graft. Postoperatively, bilateral lower limb was viable and kidney function was normal. He was discharged well. Open surgery remains the gold standard in treating such a complex case promptly.

Keywords: Abdominal aortic aneurysm, acute limb ischemia, horseshoe kidney

How to cite this article:
Tamlikha MA, Pathamanathan SS, Hussein H. Thrombosed abdominal aortic aneurysm with horseshoe kidney presenting with acute limb ischemia. Indian J Vasc Endovasc Surg 2021;8:378-80

How to cite this URL:
Tamlikha MA, Pathamanathan SS, Hussein H. Thrombosed abdominal aortic aneurysm with horseshoe kidney presenting with acute limb ischemia. Indian J Vasc Endovasc Surg [serial online] 2021 [cited 2022 Aug 15];8:378-80. Available from:

  Introduction Top

The combined presence of abdominal aortic aneurysm (AAA) and horseshoe kidney (HSK) is uncommon, whereas this phenomenon presenting with acute thrombosis and acute limb ischemia (ALI) is rare. Management requires urgent intervention and thoughtful consideration to preserve both limb and renal functions. We report such a case that was successfully managed in our center and review the technical challenges.

  Case Report Top

A 71-year-old man presented with sudden onset of numbness over his left leg. He was a smoker and had hypertension and diabetes mellitus. There was a nontender pulsatile central abdominal mass felt and his left lower limb was pulseless and had reduced sensation (Rutherford 2A). Computed tomography (CT) angiogram [Figure 1] showed a huge saccular infrarenal aortic aneurysm extending to the left external iliac artery with thrombosis of the left iliac aneurysm causing total occlusion. There was also an incidental HSK anterosuperior to the aneurysm. Emergency surgery was scheduled. Preoperative retrograde pyelogram for stenting showed a right partial duplex system [Figure 2]. A transperitoneal approach was performed and the aneurysm was exposed. The isthmus of the HSK, inferior mesenteric artery, and aneurysm neck were identified by careful dissection [Figure 3]. There was an accessory left renal artery (RA) arising from the aneurysm above the isthmus, requiring division which resulted in a significant change of color of the isthmus. Proximal and distal controls of vessels were secured with clamps prior to aneurysectomy. The thrombus was evacuated and retrograde flow was established from both external iliac arteries. Hemostasis was secured and a bifurcated graft was inserted passing through posteriorly to the renal isthmus without isthmectomy [Figure 4]. The accessory RA was reimplanted onto the graft and a return of color to the isthmus was appreciated. Postoperatively, his left lower limb was viable with a return of pulses and kidney function was monitored by serum urea–creatinine, urine output, blood pressure, and serial renal duplex sonography. He was discharged well after a week. After a year, he remains well and renal function is normal.
Figure 1: Computed tomography angiography showed infrarenal abdominal aortic aneurysm extending into the left common iliac and external iliac artery with intraluminal filling defects. There is also presence of horseshoe kidney with anterosuperior facing hila

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Figure 2: Preoperative retrograde pyelogram for stenting showed right partial duplex kidney

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Figure 3: Exposed infrarenal abdominal aortic aneurysm with horseshoe kidney. 1; Left renal vein, 2; Aneusrysmal neck, 3; Accessory left renal vein, 4; Horseshoe kidney, 5; Infrarenal aneurysm sac

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Figure 4: Post aneurysectomy with inlay bifurcated graft repair and left accessory renal artery reimplantation. 1: Proximal anastomosis, 2: Left accessory renal reimplantation, 3: Distal bifurcation anastomosis

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  Discussion Top

HSK is a congenital anomaly of bilaterally fused renal ectopia associated with vascular and urinary tract malformations. It is the most common type of fusion renal anomaly, though is only prevalent in 0.25% of the population. AAA repair with a HSK, though uncommon, has been reported before. Literature review revealed 176 cases reported between 1956 and 1999.[1] On the other hand, the incidence of acute thrombosis of an AAA is <3%,[2] and the combination of both these phenomenon raises several challenges with respect to the abnormal anatomy of the kidney itself, renal vessels, collecting system, and inferior vena cava (IVC). There is a higher incidence of anomalous IVC (5.7%) in HSK which may be double, left, or preisthmic. Due to these factors, the surgeon needs to consider the approach for repair, whether transperitoneal or retroperitoneal. Both have their merits, though transperitoneal approach is more familiar and provides better access to the contralateral iliac vessels, which is more pertinent in an emergency presenting with iliac thrombosis. Endovascular repair for AAA with HSK is an option in elective settings if the anatomy is suitable, with 32 cases having been reported.[3] However, preservation of major accessory RA and endoleak from RA that were covered remain a challenge. Furthermore, its role in a patient presenting with ALI is limited.

Renal vascular anomaly occurs in most HSKs. The two most common classifications for these variations were proposed by Eisendrath[4] and Graves.[5] In general, most HSKs have more than 3 RAs and most have accessory RA that originate below the isthmus, from either the aorta or iliac arteries.[6] This highlights the importance of preoperative imaging and intraoperative exposure. Most authors recommend preservation of RAs with a significant diameter (usually >2 mm) because their ligation may possibly lead to ischemia of the renal isthmus and renal infarcts.[6] Reimplantation of accessory RAs can be performed directly to the body of the prosthetic graft through Carrel patch.

The anatomy of the collecting system in a HSK is invariably abnormal. This is due to failure to rotate during development. The ureters may lie more medially and anterior to the isthmus with variations in number and origin,[6] posing a risk of injury during AAA repair. Ureters have been reported with bilateral duplication, crossed single ureter, ectopic draining from the isthmus, retrocaval, and three ureters. Recognizing these variations may alert the surgeon to avoid injury which may otherwise lead to catastrophic graft infection. A preoperative retrograde pyelogram and ureteric stenting aided us in preserving the ureters and alerting us to the partial duplex system on the right. In our patient, the technical difficulty in stenting both ureters of a duplex system is apparent, thus attempt should be to stent the more medial of the ureters.

When dealing with the isthmus (renal symphysis), it is tempting to divide it, as it lays anterior to the repair segment. However, injury to the isthmus increases the risk of urinary leak if it contains parenchyma and a collecting system within. This may be determined preoperatively with a CT scan that may distinguish between a functional and a fibrous isthmus. In our patient, the CT revealed a perfused isthmus, and intraoperatively, we noticed the whole isthmus supplied by the left accessory artery. Mid isthmus division would invariably have resulted in the distal segment undergoing necrosis and posing a risk of urinary leak and graft infection. Most reported cases have a parenchymal isthmus[1], and most authors agree that isthmectomy should be avoided and performed only when it hinders aortic reconstruction.[3] If the isthmus is preserved, the aortic graft should lay posterior to it, as this reduces graft length, improves linear flow, and avoids potential compression of the collecting system.

  Conclusion Top

Acute thrombosis of an AAA with coexisting HSK poses a challenge in management, with an aim to preserve kidney function and avoid injury to the surrounding structures which have a higher incidence of variation. Intervention should be prompt to return perfusion to the ischemic limb and prevent reperfusion injury that may threaten renal function which is already at risk of ischemia during accessory RA division. Open surgery remains the gold standard in such a complex case.

Declaration of patient consent

The authors certify that they have obtained all appropriate patient consent forms. In the form the patient(s) has/have given his/her/their consent for his/her/their images and other clinical information to be reported in the journal. The patients understand that their names and initials will not be published and due efforts will be made to conceal their identity, but anonymity cannot be guaranteed.

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Conflicts of interest

There are no conflicts of interest.

  References Top

Stroosma OB, Kootstra G, Schurink GW. Management of aortic aneurysm in the presence of a horseshoe kidney. Br J Surg 2001;88:500-9.  Back to cited text no. 1
Vasdekis SN, Mastoraki S, Lazaris A, Moulakakis KG. An unusual case of acute thrombosis of abdominal aortic aneurysm without acute limb ischemia. Aorta (Stamford) 2018;6:31-3.  Back to cited text no. 2
Sachsamanis G, Charisis N, Maltezos K, Galyfos G, Papapetrou A, Tsiliggiris V, et al. Management and therapeutic options for abdominal aortic aneurysm coexistent with horseshoe kidney. J Vasc Surg 2019;69:1257-67.  Back to cited text no. 3
Eisendrath DN, Phifer FM, Culver HB. Horseshoe kidney. Ann Surg 1925;82:735-64.  Back to cited text no. 4
Graves FT. The arterial anatomy of the congenitally abnormal kidney. Br J Surg 1969;56:533-41.  Back to cited text no. 5
Natsis K, Piagkou M, Skotsimara A, Protogerou V, Tsitouridis I, Skandalakis P. Horseshoe kidney: A review of anatomy and pathology. Surg Radiol Anat 2014;36:517-26.  Back to cited text no. 6


  [Figure 1], [Figure 2], [Figure 3], [Figure 4]


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