Single versus multiple renal arteries in living donor kidney transplantation: A systematic review and patient-level meta-analysis

INTRODUCTION

Grafts with multiple renal arteries (MRAs) were historically considered a relative contraindication to transplantation due to the higher risk of vascular and urologic complications. This study aimed to evaluate graft and patient survival between single renal artery (SRA) and MRA living-donor kidney transplants.

METHODS

An electronic literature search was conducted on PubMed, EMBASE, and Scopus for prospective or retrospective studies comparing SRA versus MRA in living donor renal transplantation, with the provision of Kaplan-Meier curves for recipient overall survival (OS) or graft survival (GS). A graphical reconstructive algorithm was used to obtain OS and GS of individual patients, which was then pooled under random-effects individual patient data (IPD) meta-analysis using Cox-models to determine hazard ratios (HRs) and 95% confidence intervals (CIs). Meta-regression of baseline covariates versus HRs of OS and GS was performed for variables reported in 10 or more studies.

RESULTS

Fourteen studies were retrieved, of which 13 (8400 patients) reported OS and 9 (6912 patients) reported GS. There were no significant differences in OS (shared-frailty HR = .94, 95%CI = .85-1.03, p = .172) or GS (shared-frailty HR = .95, 95%CI = .83-1.08, p = .419) between SRA and MRA. This comparison remained non-significant even when restricted to open- or laparoscopic-only studies. Meta-regression yielded no significant associations of GS with donor age, recipient age, and percentage of double renal arteries within the MRA arm.

CONCLUSIONS

The similar rates of GS and OS between MRA and SRA grafts suggest that there is no need for discrimination between the two when evaluating donors for nephrectomy.

Pediatric kidney transplants with multiple renal arteries show no increased risk of complications compared to single renal artery grafts

Background

Kidney allografts with multiple renal arteries (MRA) are not infrequent and have been historically associated with a higher risk of developing vascular and urologic complications. Reports of kidney transplantation using MRA allografts in the pediatric population remain scarce. The aim of this study was to evaluate if transplantation of allografts with MRA with a surgical intent of creating a single arterial inflow using vascular reconstruction techniques when required, and without the routine use of surgical drains or ureteral stents, is associated with an increased risk of complications when compared to single renal artery (SRA) grafts.

Methods

We retrospectively analyzed all pediatric renal transplant recipients performed by a single surgeon at our center between January 2015 and June 2022. Donor and recipient demographics, intraoperative data, and recipient outcomes were included. Recipients were divided into two groups based on SRA vs. MRA. Baseline variables were described using frequency distributions for categorical variables and means and standard errors for continuous variables. Comparisons of those distributions between the two groups were performed using standard chi-squared and t-tests. Time-to-event distributions were compared using the log-rank test.

Results

Forty-nine pediatric transplant recipients were analyzed. Of these, 9 had donors with MRA (Group 1) and 40 had donors with SRA (Group 2). Native kidney and liver mobilization was performed in 44.4% (4/9) of Group 1 vs. 60.0% (24/40) of Group 2 cases (p = 0.39). There were no cases of delayed graft function or graft primary nonfunction. No surgical drainage or ureteral stents were used in any of the cases. One patient in Group 2 developed a distal ureter stricture. The geometric mean serum creatinine at 6- and 12-months posttransplant was 0.7 */ 1.2 and 0.9 */ 1.2 mg/dl in Group 1 and 0.7 */ 1.1 and 0.7 */ 1.1 mg/dl in Group 2. Two death-censored graft failures were observed in Group 2, with no significant difference observed between the two groups (p = 0.48).

Conclusions

Our study demonstrates that pediatric renal transplantation with MRA grafts, using a surgical approach to achieve a single renal artery ostium, can be safely performed while achieving similar outcomes as SRA grafts and with a low complication rate.

Current practice with grafts with multiple renal arteries in kidney transplantation: role of the methylene blue in the lower pole

Kidneys with multiple renal arteries (MRAs) from different patches, may provide to the surgeon additional technical difficulties that make kidney transplants very challenging. MRAs have been largely debated over the years whether to be anastomosed or not due to the disappointing outcomes when it comes to inappropriate ligation or anastomosis.  Some authors empirically reassure that smaller branches can be safely ligated and dissected without intraoperative and postoperative complications or compromising the functional recovery of the graft. Literature is poor about the possible differences in the management of superior and inferior polar arteries. Inferior polar arteries represent a topic of great interest as they may also supply the proximal ureter. The aim of this article is to merge the current knowledge about the management of inferior polar arteries and to highlight if there is any role of the methylene blue dye (MB) in the study of the ureteral vascularization in kidney transplantation. MB can be considered a safe and simple tool of vascular perfusion assessment in kidney transplantation. By injecting the dye-solution into the inferior MRA hidden ureteral branches can be unmasked and guide the surgeon to preserve important vessels. In view of their fundamental role in the vascularization of the ureter, the lower polar arteries of the graft, should be invariably studied by MB. It provides an objective, simple and fast tool for the evaluation of the ureteral vascularization when injected through the inferior MRA of the graft.

Hypertension and renal outcomes in normotensive kidney donors with multiple renal arteries

Having multiple renal arteries (MRA) has been linked to hypertension development. Whether kidney donors who are left with MRA in the nondonated kidney incur a higher risk of hypertension has not been studied. We compared the development of hypertension, reduced estimated glomerular filtration rate (eGFR), cardiovascular disease, and mortality in 2624 normotensive kidney donors with MRA in the nondonated kidney and to 2624 propensity score matched normotensive donor controls with a single renal artery. In total, 35% of donors had MRA. Donors with MRA were less likely to have undergone a left nephrectomy (51% vs. 83%). Postdonation hypertension was associated with age, male gender, non-White ethnicity, obesity, and family history of hypertension. Having MRA was not associated with risk of hypertension; aHR 0.92 (95% CI 0.82-1.03), P = 0.16. After 17 ± 11 years from donation, a similar proportion of donors with and without MRA developed cardiovascular disease, proteinuria and eGFR <30, <45 and <60 mL/min/1.73 m² and the multivariable risks of developing these outcomes were similar in the two groups. Our study did not show increased risk for hypertension, reduced eGFR, proteinuria or cardiovascular disease in donors with MRA in the remaining kidney and without hypertension at donation.

Methylene blue usage for determining accessory artery ligation in donor kidneys

Objectives. We present a technique for determining whether to ligate or preserve accessory arteries in donor kidneys before implantation. Methods. Forty-three living-related donor kidneys in patients from January 2014 to February 2018 at our institution were included, all of which had dual arteries without the same stem. Among them, 19 cases of accessory arterial blood supply were evaluated using methylene blue (MB) perfusion, and accessory arteries supplying less than 10% of the total MB perfusion volume were ligated. The other 24 cases were assessed using a conventional method in which arteries with diameters less than 2 mm were ligated. The back-table surgical time, Doppler ultrasonography index, renal function and complications were compared between the 2 groups. Results. All patients underwent successful kidney transplantation. The back-table surgical time in the MB group was longer than that in the conventional group (42.70 ± 4.70 min vs 34.64 ± 5.30 min, P < .05). The serum creatinine level in the MB group was significantly lower than that in the conventional group 1 month after the operation (103.15 ± 19.26 μmol/L vs 119.17 ± 28.32 μmol/L, P < .05). No differences in the Doppler ultrasonography index or postoperative complications were noted. Conclusions. MB perfusion provides an easy and effective method to make decisions regarding arterial ligation and helps preserve renal function without increasing the number of complications after transplantation.

A case of solitary kidney with duplex collecting systems and renal vascular variants in an adult male cadaver

We describe a unique solitary kidney with duplex collecting system and vascular variation observed in an 86-year-old white male formaldehyde- and phenol-fixed cadaver during routine academic dissection. The left renal fossa was empty with an intact adrenal gland, and the right renal fossa contained a fused renal mass with apparent polarity between the superior and inferior regions and two renal pelves converging into a single ureter. There were three right renal arteries supplying the renal mass; the superior and middle arteries were noted to be postcaval and the inferior artery was precaval. There were also two right renal veins draining into the inferior vena cava and following a regional distribution with the superior vein draining the inferior portion of the renal mass. Despite generally being asymptomatic, the detection of renal anatomical variants is clinically important for appropriate patient management and surgical interventions.

Bilateral inferior renal polar arteries with a high origin from the abdominal aorta

Bilateral multiple renal arteries are not-so-rare variations. However, inferior renal polar arteries with a high origin from the abdominal aorta have rarely been reported. We found bilateral inferior renal polar arteries with a high origin from the abdominal aorta in an 84-year-old Korean female cadaver. Two right and three left renal arteries were seen with the lowest as the main renal artery bilaterally. The highest artery crossed the main renal artery and penetrated into the inferior pole of the kidney, respectively. After dissection, each inferior polar artery could be classified as the inferior segmental branch. A further understanding on its embryogenesis might be important since variations in renal arteries are of particular interest to clinicians as well as anatomists.

Diameters of Arteries Supplying Horseshoe Kidneys and the Level They Branch off Their Parental Vessels: A CT-Angiographic Study

Background: The most common renal fusion anomaly is horseshoe kidney (HSK), a condition associated with variable arterial blood supply. The aim of this study was to determine whether the height of origin of the renal artery determines its diameter and whether it differs from the mean diameter of the renal arteries of normal kidneys (NK). Methods: Computer tomography angiography (CTA) studies of 336 patients (88 HSK and 248 NK) were obtained in a search of renal arteries; these were than classified into four groups according to height of its origin: Group I, branching from the aorta superior to the inferior mesenteric artery (IMA); Group II, branching from the aorta below the IMA; Group III, branching from the iliac artery; and Group IV, originating from the internal and external iliac artery. Results: The HSK group included 398 arteries (mean diameter 4.30 mm) and the NK group 598 (5.52 mm) (p < 0.0001). In the HSK group, the mean diameters according to groups were: Group I, 4.54 mm; Group II, 4.28 mm; Group III, 3.41 mm; and Group IV, 3.43 mm. Statistically significant differences were found between arteries originating from the aorta and arteries branching from the iliac arteries (p < 0.0001). In the NK group, the corresponding values were: Group I, 5.53 mm; and Group II, 4.45 mm. The number of arteries supplying the HSK wider than 3.0 mm were: Group I, 83.0%; Group II, 82.4%; Group III, 68.4%; and Group IV, 66.6%. Conclusions: The renal arteries of the HSK branch from their parental vessels at lower levels and have smaller diameters than those of NK.

When one becomes more: minimum renal artery length in laparoscopic live donor nephrectomy

BACKGROUND

Laparoscopic donor nephrectomy may convert short main arteries into multiple arteries, increasing the technical challenge of implantation. We evaluated our experience to identify factors predictive of multiple arteries after laparoscopic nephrectomy.

METHODS

All laparoscopic nephrectomies from the start of our program in November 2002 until June 2013 were studied, and preoperative imaging reviewed for donor artery length and multiplicity together with operative findings.

RESULTS

A total of 287 consecutive laparoscopic live donor nephrectomies (64 right and 223 left nephrectomies) were studied. Renal artery length was measured from preoperative donor magnetic resonance or computed tomography angiogram and nephrectomy performed using a laparoscopic stapling device. Nine left kidneys with a single artery (6, 7, 9, 10, 11, 12, 13, 14, and 16 mm in length) and five right kidneys with a single artery (5, 13, 15, 20, and 26 mm) on imaging resulted in multiple renal arteries at implantation. Complex renal vein anatomy was associated with multiple arteries following retrieval.

CONCLUSION

A main renal artery length of more than 16 mm on the left and 26 mm on the right is unlikely to result in multiple arteries to implant. The possibility of multiple arteries should be borne in mind when the donor renal artery is short.

A right ectopic kidney with bilateral multiple anomalies of the renal vasculature - a case report

The renal anatomy and its development is complex. This complexity is associated with numerous variations. Each renal variation has its own clinical and surgical importance. There is a good correlation between the ascent of the kidney, the level of its origin and number of the renal arteries. Any anomaly in the renal artery development may be due to a delay in the kidney ascension and it can lead to an ectopic kidney. Ectopic kidneys are more frequent in males and they are observed commonly on the left side. In the present study, we came across a rare case of a unilateral right renal ectopia and bilateral multiple renal arteries, with 5 renal arteries on the right side and 2 on the left side. The renal veins were 3 on the right side and two on the left side, with the retro aortic left renal vein, which were observed during the routine dissection of a male cadaver. This observation would be of immense importance for surgeons, interventional radiologists, nephrologists and vascular surgeons.

Outcomes of laparoscopic donor nephrectomy in the presence of multiple renal arteries

Purpose:

Data of laparoscopic donor nephrectomy (LDN) with multiple renal arteries for donor and recipient outcomes were reviewed, with the aim of clarifying whether the laparoscopic approach is safe in the presence of multiple renal arteries.

Materials and Methods:

All donor nephrectomies performed at our institution from 2004 to 2008 were reviewed retrospectively. Results were compared between LDN kidneys with multiple arteries and those with a single renal artery.

Results:

Out of 171 donor nephrectomies, 21 (12%) were performed for kidneys with multiple renal arteries. All of the 150 (88%) donor nephrectomies in the single vessel group were performed laparoscopically. In the multiple artery group, 9 (43%) underwent an open procedure while 12 (57%) underwent a laparoscopic procedure. The warm ischemia time was longer in the multiple artery group than the single artery group, but the difference was not statistically significant (4.25±0.87 min vs. 4.12±0.95 min, respectively). Regarding transplant recipients, the vascular anastomosis time was similar in both groups (30±4.6 min vs. 29.5±3.7 min). The operative blood loss in the transplant recipients was significantly more in the multiple artery group compared to the single artery group (339±292 ml and 130.7±44.8 ml, respectively; P=0.03). The recipient renal function was similar for both the groups at postoperative day 7, 1 month, and at 1 year.

Conclusion:

The data support the fact that the laparoscopic approach to donor nephrectomy in the presence of multiple renal arteries can be performed safely with adequate laparoscopic experience.