Congenital bilateral iliac vein anomalies in a Nigerian pediatric kidney transplant recipient: A case report and literature review.

The finding of bilateral congenital common iliac vein anomalies is indeed uncommon. This article presents the case of an 11-year-old boy with end-stage renal disease who had kidney transplantation (KT). At presentation, he was found to have a large superficial vein running from the left groin over the suprapubic area. The arterial pulsation of both lower limbs was preserved, and there was no pedal edema. Contrast-enhanced computed tomography scan revealed aplasia of the right common iliac vein, stenosis of the left common iliac vein, and marked dilatation of the left external and internal iliac veins. There were also varicosity of numerous pelvic veins and a collateral vein draining the right lower limb. This preoperative diagnosis was key to planning for surgery. On KT surgery, the renal allograft vein was anastomosed in an end-to-side fashion to the inferior vena cava and artery to the common iliac artery. The patient had a smooth postoperative recovery and continues to enjoy a normal renal function.

INTRODUCTION

Congenital vascular abnormalities are not uncommon in the general populace. They are however mostly assymptomatic and rarely encountered in the work-up for kidney transplantation. Among the major venous congenital anormalies, transposition of the inferior vena cava (IVC), duplication of the IVC, circum-aortic renal collar and retro-aortic renal veins are the most frequently encountered.[1]

The right and left postcardinal veins are responsible for the drainage of the lower limbs and pelvis in intra-uterine life. The inter-postcardinal anastomosis forms a definitive part of the common iliac veins and links both veins across the midline running in an oblique transverse fashion.[23] The congenital unilateral absence of the external iliac vein as seen in the index case is among the rarest of vascular abnormalities known to man as shown by Shabaan et al.[4] Aplasia of the common iliac veins have however been reported in a turkish boy.[5]

Renal transplantation is the mainstay in treatment of end-stage renal disease (ESRD) . The right iliac fossa is usually preferred as the site of allograft placement and the renal allograft vein and artery are anastomosed with the right external iliac vein and external/internal iliac artery respectively. A thorough knowledge of the vascular anatomy and awareness of any vascular anormaly are crucial to avoiding diagnostic pitfalls and surgical mishaps in kidney transplant surgery.[6] Absence of iliac veins in the recipient could create a dilemma intra-operatively for the kidney transplant surgeon and would require high level of expertise in order to use alternative veins. Such circumstances buttress the role of a thorough pre-operative radiological evaluation of the abdominal and lower limb vasculature to forestall surprise intra-operative findings. This case report described the surgical management of a male paediatric ESRD patient with congenital absence of the right common, external and internal iliac veins who underwent kidney transplantation in our facility.

CASE REPORT

An 11-year-old boy presented to our clinic with symptoms of end-stage renal disease diagnosed to be secondary to bilateral renal artery stenosis. He was subsequently placed on twice-weekly hemodialysis and had right internal jugular venous catheterization for vascular access. He had no symptoms suggestive of lower limb venous insufficiency such as limb edema or venous thrombosis. However, he had a prominently dilated vein running over the lower abdomen from the right inguinal region. He was subsequently put on the renal transplant list, and evaluation for transplant was commenced.

A computed tomography (CT) angiogram demonstrated an aplastic right common iliac vein with absence of the ipsilateral external and internal iliac veins in their anatomical positions [Figure 1A]. There was associated tapering and obliteration of the right inferior conus of the inferior vena cava (IVC) [Figure 1A]. Multiple vascular channels suggestive of collateral circulation were demonstrated in the deep and superficial pelvic region, more on the left side [Figure 1C].

Figure 1

An 11-year-old boy with aplastic right common iliac vein and stenotic left common iliac vein. Findings: Three-dimensional volume-rendered coronal reconstructed contrast-enhanced computed tomography angiogram of the abdomen in the venous phase showing: (A) Aplastic/stenotic right common iliac vein. (B) Stenotic short left common iliac vein with dilatation of the external and internal iliac vein. (C) Multiple collateral venous channels. (D) Anomalous suprapubic collateral vein. (E) Collateral venous drainage of the right lower limb to the left common iliac vein. Technique: Three-dimensional volume rendered (VR) Computer tomography angiogram 0.9 s, 120 kV, 10 mm slice thickness, and 60 mL of iohexol contrast (370 mg/mL)

An anomalous curved suprapubic vein was seen connecting the superficial dilated veins to the left external iliac vein [Figure 1D]. There was a short stenotic left common iliac vein draining into the IVC from the left side with marked dilatation of the distal external and internal iliac tributaries [Figure 1B]. There was also varicosity of the sacral, hypogastric, and psoas plexus of veins. There was also a collateral venous channel draining from the right inguinal region into the left stenotic common iliac vein [Figure 1E].

There was also an avid simultaneous contrast opacification of both the aorta and IVC in the arterial phase, with a subtle connection demonstrated between the left common femoral artery and vein at the level of the groin, suggestive of an arteriovenous fistula [Figure 2].

Figure 2

An 11-year-old boy with aplastic right common iliac vein and stenotic left common iliac vein. Findings: Coronal reconstructed computed tomography angiogram osf the abdomen and pelvis (arterial phase) showing: (A) Arteriovenous fistula between the left femoral artery and vein. (B) Left femoral artery. (C) Left femoral vein. Technique: Coronal computed tomography angio 0.9 s, 120 kV, 10 mm slice thickness, and 60 mL of iohexol contrast (370 mg/mL)

The abdominal aorta and iliac arteries were, however, essentially normal [Figure 3].

Figure 3

An 11-year-old boy with aplastic right common iliac vein and stenotic left common iliac vein. Findings: Three-dimensional VR coronal reconstructed computed tomography angiogram showing (A) right external iliac artery with absence of iliac veins (B) left external and internal iliac vessels. Technique: Three-dimensional VR coronal computed tomography angio 0.9 s, 120 kV, 10 mm slice thickness, and 60 mL of iohexol contrast (370 mg/mL)

On physical examination, the femoral arterial and dorsalis pedis pulsations on both lower limbs were normal.

He subsequently had a living blood-related renal transplantation done, with the anastomosis performed between the allograft renal vein and the IVC, whereas the allograft renal artery was anastomosed with the external iliac artery both in an end-to-side fashion. The decision was made preoperatively, hence saving time intraoperatively. He made a smooth postoperative recovery with good function of the renal allograft. He is currently at 1-year posttransplantation and is being seen in the outpatient clinic with good renal function.

DISCUSSION

A thorough preoperative evaluation of patients for KT is important in diagnosing asymptomatic vascular malformations, which could determine the success of the transplant surgery. Aplasia of unilateral common and external iliac veins has been reported in literature as a very rare anomaly.[57] It may occur in isolation but more commonly as part of a syndrome of multiple congenital vascular abnormalities as in Klippel–Trenaunay syndrome and phakomatosis pigmentovascularis.[78] Differentials such as Crockett's syndrome, also known as May–Thurner syndrome, where there is an external compression of the left iliac vein by the right iliac artery, should also be excluded. Presence of such congenital anomalies in a KT recipient could affect the choice of the site for allograft implantation and the vessels used for anastomosis, as described by Al Midani et al.[9]

Chronic venous insufficiency as a result of absent deep lower limb veins can present with venous hypertension, venous thrombosis, and eventually venous ulcers.[10] Except for the suprapubic varicose vein, these were however absent in the index patient, perhaps due to the patent collateral drainage to the contralateral iliac vein.

The CT angiography enabled the diagnosis to be made in this instance and hence prepared the transplant surgeon for the procedure. The findings of other congenital vascular problems such as bilateral renal stenosis, multiple common iliac veins on the left, and abnormal collaterals suggest that such abnormalities may run a syndromic course and hence require a high index of suspicion to look out for others.

Remarkably, the index patient had an uneventful recovery and has maintained a good renal function 1-year posttransplant.

Teaching point

Although rare, congenital vascular abnormalities of the iliac vessels may occur in patients who undergo KT. A thorough preoperative evaluation of the recipient by physical examination and radiological vascular imaging is necessary in order to appropriately plan for surgery. The choice of site of allograft implantation and vessels for anastomosis can be influenced by these findings. These factors contribute enormously to the success of KT surgery.

Declaration of patient consent

The authors certify that they have obtained all appropriate patient consent forms. In the form, the parents have given their consent for the child's images and other clinical information to be reported in the journal. The parents understand that the child's name and initial will not be published, and due efforts will be made to conceal identity, but anonymity cannot be guaranteed.

Financial support and sponsorship

Nil.

Conflicts of interest

There are no conflicts of interest.