EXPERIMENTAL AND CLINICAL TRANSPLANTATION

Implantation of kidneys with multiple renal arteries increases rewarming time and is associated with higher delayed graft function and poorer outcomes. Polar arteries originating from the aorta are found in up to 10% of donors and are small in diameter (1.5-3 mm). Traditionally, lower polar arteries are revascularized with the inferior epigastric artery to avoid ureteric ischemia, and upper polar arteries are ligated based on the assumption that long-term graft function is not affected. The revascularization and reconstruction of these small polar arteries are difficult and increase ischemic times along with a significant risk of arterial complications. Separate implantation of upper polar arteries and the main renal artery to the external iliac artery is only possible with “clamps on” and would increase rewarming time. On the other hand, connecting an upper polar artery to the main renal artery or one of its branches could jeopardize the patency of the main artery. We describe a simple revascularization technique for upper polar arteries deemed >2 mm using the inferior epigastric artery, without increase in rewarming time.

Key words : Arterial anastomosis, Kidney transplant, Perfusion, Polar arteries, Upside-down implantation

Implantation of kidneys with multiple renal arteries increases rewarming time (RWT) and is associated with higher delayed graft function and ureteric complications.^1-3 Polar arteries originating from the aorta are found in up to 10% of donors and are small in diameter (1.5-3 mm).⁴ Traditionally lower polar arteries (LPA) are revascularized with the inferior epigastric artery (IEA) to avoid ureteric ischemia, and upper polar arteries (UPA) are ligated^3,5 based on the assumption that long-term graft function is not affected.⁶ Ligation has been suggested for polar arteries that are less than 2 mm or supply less than 10% of renal parenchyma.⁵ Both revascularization and reconstruction of these small polar arteries are difficult and increase ischemic times along with a significant risk of arterial complications.^1,5,7,8 Separate implantation of UPAs and the main renal artery to the external iliac artery (EIA) is only possible with a “clamps-on” method and would increase RWT. On the other hand, connecting the UPA to the main renal artery or to a branch of the renal artery could jeopardize the patency of the main artery.^7-9 We describe a simple revascularization technique for UPAs deemed >2 mm using the IEA, without an increase in RWT.

Surgical technique
Donor kidneys are placed retroperitoneally in the right iliac fossa for end-to-side anastomosis of the main renal vessels to the external iliac vessels with running 6/0 polypropylene sutures. The IEA is dissected to gain extra length in anticipation of revascularizing the UPA (Figure 1), which is also prepared for this anastomosis. The UPA is deemed implantable only if its lumen admits an 18-gauge green intravenous cannula that can demonstrate successful hydrodilation (Figure 2). The implantation strategy is to place the kidney upside down with the ureter cephalad so that the upper pole becomes the lower pole, to lie near the IEA. Clamps are removed after the end-to-side vascular anastomosis to the external iliac vessels is completed, which allows perfusion of the bulk of the graft, except for the area supplied by the UPA. Next, the UPA is anastomosed end-to-end to the IEA with interrupted 7/0 polypropylene sutures to achieve global perfusion (Figure 3). The ureter is then implanted using the extravesical technique and stented.
Case patients
Patient 1, a 41-year-old male kidney transplant recipient, received a right kidney from his spouse via open donor nephrectomy. This graft had 2 renal arteries, a main hilar renal artery, and a smaller UPA for which the IEA was prepared (Figure 4, A and B). This right kidney was implanted upside down with the ureter up, on the right side of the recipient. Clamps were removed after the vascular anastomoses, and the kidney demonstrated satisfactory perfusion except for the area supplied by the UPA with immediate graft function. The UPA was then revascularized with the IEA to achieveglobal perfusion (Figure 4C), which was confirmed by postoperative Doppler ultrasonography.
Patient 2, a 43-year-old male recipient, received a left kidney from his 28-year-old spouse. This donor left kidney had a single hilar artery and a small UPA (Figure 5A) for which the IEA was prepared. This kidney was implanted upside down in the right iliac fossa, and clamps were removed after the vascular anastomoses, with successful perfusion of the bulk of the kidney, with brisk diuresis. The UPA was then revascularized end-to-end with the IEA to achieve global perfusion (Figure 5B), which was confirmed by postoperative Doppler ultrasonography.
Patient 3, a 27-year-old male recipient, received a kidney from his 29-year-old brother via a left open donor nephrectomy. This left kidney had 3 renal arteries, 2 hilar arteries, and 1 UPA (Figure 6, A and B). A single lumen was created for the 2 larger hilar arteries, and the UPA was planned for end-to-end anastomosis to IEA. The kidney was implanted upside down, with the ureter up; perfusion after completion of the vascular anastomosis demonst-rated immediate graft function. The UPA was then anastomosed to the IEA to achieve global perfusion (Figure 6C), which was confirmed by postoperative Doppler ultrasonography.

Transplant of allografts with multiple renal arteries is technically more demanding because of increased risk of vascular and ureteral complications.⁹ A recent meta-analysis has shown an increased risk of delayed graft function and a decreased 1-year graft survival compared with single renal artery allografts.¹⁰ There is consensus on using the IEA for revascularization of LPAs, primarily to preserve ureteric blood supply, but ligation of UPAs and loss of ±10% parenchyma has been traditionally acceptable.^5,9,11 The use of the IEA for revascularization of LPAs is convenient because of the natural anatomic proximity. The same proximity can be achieved for UPAs by upside-down placement of the kidney, with the ureter cephalad, which converts a UPA into an LPA. With the UPA in this position, it can be anastomosed easily to the IEA without clamps on the EIA. This so-called “off-clamp” UPA revascularization does not increase the RWT and therefore does not hinder initial graft function, and all of our cases presented here have demonstrated this success. We used a simple and practical method to choose the proper size of polar artery for revascularization; that is, all arteries that admit an 18-gauge green intravenous cannula are revascularized (Figure 2).
Upside-down implantation of kidneys has been shown to be safe. Simforoosh and colleagues described their success with inverted right-to-right transplants in kidneys with short veins.¹² Emmanoulidis and colleagues unintentionally implanted inverted kidneys that did well, and they have since added this uncon-ventional technique to their armamentarium for cases with complex vascular situations; in fact, they have considered using this approach for all ipsila-teral transplants.¹³ We also have found this upside-down technique to be useful in ipsilateral transplants and in recipients with redundant EIAs, for which this method was found to be ergonomically more con-venient to site the arterial anastomosis on the distal EIA, irrespective of kidney laterality (unpublished data). In preparation for this method, we dissect and skeletonize the IEA to gain length in all cases with polar arteries, in anticipation of revascularization. Sequential anastomosis of the LPA to the IEA after removal of clamps allows perfusion of the bulk of the kidney, leaving the small area of the renal parenchyma to be revascularized, “off clamp”, a few minutes later.³ This method, which does not involve any type of reconstruction of the main renal artery, appears to be an ideal solution that does not increase RWT and protects the main artery.^7-9 In our practice, we aim to preserve the greatest possible mass of renal parenchyma by connecting all polar arteries. Here, we present a simple solution for revascularization of UPAs by inversion of the kidney followed by anastomosis to the IEA after perfusion of the graft via its main artery.
The use of IEA for anastomosis to LPAs is an established technique; herein, we have presented the first case series of sequential anastomosis of IEA to UPAs by implanting the graft upside down. Preservation of all implantable UPAs is important, because revascularization of UPAs facilitates salvage of up to 10% of upper polar nephrons that would otherwise be lost.

Volume: 23 Issue: 11 November 2025

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