The Arterial Anastomosis Between Deep Inferior Epigastric Artery and Small Polar Renal Artery in Kidney Transplantation: A Case Report

The presence of multiple renal arteries is the most common form of vascular anomalies found in donor kidneys. In rare cases, small renal polar arteries may be found. They can be anastomosed with deep inferior epigastric arteries, resulting in vascular augmentation of transplanted kidneys and contributing to better graft function. Renal perfusion may be increased via 2 types of vascular reconstruction known as “turbocharging” and “supercharging”. Turbocharging uses vascular sources within the same organ area, whereas supercharging uses distant vascular sources. Using additional vessels can either complicate the surgery or, contradictorily, ease the way of procedure. This case study presents a kidney transplant during which arterial anastomosis between deep inferior epigastric artery and small polar renal artery was performed.     

Upside-down kidney placement: An alternative in pediatric renal transplantation

Purpose“Upside-down” kidney placement has been reported as an acceptable alternative in cases of technical difficulty in kidney transplantation but there are few reports in the pediatric population.The aim of our study is to analyze whether the placement of the upside-down kidney could affect graft outcome or produce more complications.Materials and methodsA retrospective study was conducted of pediatric kidney transplants performed in our center between 2005 and 2017 with at least 6 months' follow-up.Epidemiological and anthropometric data, type of donor (deceased/living), graft position (normal/upside-down), reason for the upside-down placement, early, medium and long-term complications and renal function were analyzed and compared with patients transplanted in the same period with a normal graft placement.ResultsFrom 181 transplants, 167 grafts were placed in a normal position (mean age: 10 y and mean weight: 30 kg) and 14 were placed upside-down (10 y, 37 kg) mainly because of vessel shortness after laparoscopic nephrectomy. Male predominance was observed in both groups.57% of grafts from the control group and 64% of those from study group came from a living donor.Four vascular and two ureteral re-anastomoses were recorded in the control group and two vascular and one ureteral re-anastomosis in the study group (p > 0.05). In the latter group, no grafts have been lost due to vascular or urological causes and no patients have required dialysis.ConclusionsWhen necessary, an upside-down placement for the renal graft is a safe alternative in the pediatric population.Level of evidenceLevel III.     

Advanced abdominal arterial calcification sparing kidney allograft—case report

Abstract

Excess and progressing arterial calcification is a frequent finding in patients with chronic kidney disease and in diabetics. Vascular calcification present in patients on dialysis, usually continues to progress (although possibly with slower rate) in patients after kidney transplantation. These observations are limited mostly to aorta and coronary arteries; virtually no data exist on progression in vascular calcification within the vasculature of transplanted kidney. The case report presents the patient with diabetes and non-functioning renal transplant back on dialysis with extremely severe intra-abdominal artery calcification, sparing renal artery of transplanted kidney. Calcification did not develop within transplanted kidney despite 10 years of exposition to diabetic environment and a few years of chronic kidney disease after transplantation, including CKD-T stage 5 for at least one year after re-starting of dialysis. To the best of our knowledge, this is the second report ever describing sparing of kidney graft from calcification despite disseminated calcification in other vascular beds. It is tempting to speculate that some “intrinsic” factors exist within the transplanted kidney that protects it from calcification despite exposure to procalcifying milieu of diabetes and uremia.     

The “oldest and coldest” shipped living donor kidneys transplanted through kidney paired donation

To date, thousands of living donor kidneys have been shipped through kidney paired donation (KPD). To expand on this growing segment of living donor transplantation, we evaluated the effect of advanced age donation (“oldest kidneys”) and prolonged cold ischemia time (“coldest kidneys”) on graft function and survival using the National Kidney Registry database from February 2008 to May 2018. Donors were stratified by age at time of donation (<65 or ≥65 years) and kidneys were stratified by cold ischemia time (<16 or ≥16 hours). We evaluated delayed graft function and death‐censored graft failure (DCGF) for up to seven posttransplant years. Of the 2363 shipped living donor kidney transplants, 4.1% of donors were ≥65 years and 6.0% of transplanted kidneys had cold ischemia times ≥16 hours. Delayed graft function and DCGF occurred in 5.2% and 4.7% of cases. There were no significant associations between delayed graft function and donor age (P = .947) or cold ischemia (P = .532). Donor age and cold ischemia time were not predictive of delayed graft function (OR = 0.86,1.20; P = .8, .6) or DCGF (HR = 1.38,0.35, P = .5, .1). These findings may alleviate concerns surrounding the utilization of kidneys from older donors or those originating from distant transplant centers.     

Use of spiral vein graft in living donor renal transplantation

Prosthetic material or vascular homografts have been used for vascular reconstruction in organ transplants. An alternative procedure using the spiral saphenous vein graft to lengthen 19 short-living donor kidney vessels is described.     

Pre-emptive kidney transplantation: the attractive alternative

Background: Dialysis can be life-saving for patients with end-stage renal failure. However, not only is it associated with significant morbidity and a greater mortality than transplantation, but it is also expensive. Therefore renal transplantation is generally regarded as the treatment of choice for patients in whom this form of renal replacement therapy is appropriate. Transplantation usually takes place after a variable period of dialytic therapy, but pre-emptive kidney transplantation (PKT) has established itself as an attractive alternative. Materials and methods: 1463 consecutive first kidney transplants performed between January 1980 and December 1995 in a single centre were analysed. The 161 patients (11%) transplanted without prior dialysis were compared with the 1302 patients who had been dialysed prior to being transplanted. The pre-emptive group did not differ from the dialysis group in respect of donor age, donor and recipient gender, HLA mismatch, or cold ischaemic time, although there were more live donor transplants within the pre-emptive group. Results: Delayed graft function occurred more frequently in the dialysis group (25% vs 16%) but more patients experienced an acute rejection episode in the pre-emptive group (67 vs 55%). The actuarial graft survival in the pre-emptive group at 1, 5, and 10 years (84, 76 and 67%) was significantly higher than the respective values in the dialysis group (83, 69, and 56%). Within the live donor recipient cohort the survival advantage for the pre-emptive group was even more striking. Conclusion: Pre-emptive kidney transplantation not only avoids the risks, cost, and inconvenience of dialysis, but is also associated with better graft survival than transplantation after a period of dialysis, particularly within the live donor cohort.     

Effect of increased arterial resistance index on long‐term outcome of well‐functioning kidney grafts

Abstract An abnormal vascular status is present in the transplanted kidney. To define whether vascular factors might influence kidney function of the graft, the renal volume, blood flow and vascular resistance of a group of healthy subjects were compared with those of a group of well functioning renal transplants by color Doppler ultrasonography. Sixty healthy subjects and 75 well functioning cadaver renal transplant recipients were compared by color Doppler ultrasonography. Subsequently, 15 couples of donors and recipients of a living related renal graft were compared to observe the differences between the two organs of the same subject in a different environment. The variables studied were: the diameters and the volume of the kindey, renal blood flow and renal resistance index (RI). The group of cadaver renal transplant patients showed higher mean blood pressure (P = 0.009), higher serum creatinine levels (P = 0.0001) and lower endogenous creatinine clearance (P < 0.0001) than healthy controls. The length (P < 0.00001) and volume (P < 0.001) of the kidneys of cadaver transplanted patients were significantly greater than those of healthy subjects, while the length and volume of the living donors kidneys were identical to those of the recipients. RI, measured on renal vessels, showed lower values in healthy subjects and in kidney donors than in transplantated patients (P < 0.00001). Well functioning transplanted kidneys showed increased renal arterial RI. This non‐immunologic factor did not appear to be detrimental with renal function in time, at least until 50 months after successful grafting.     

Left versus right deceased donor renal allograft outcome

It has been suggested that the left kidney is easier to transplant than the right kidney because of the longer length of the left renal vein, facilitating the formation of the venous anastomosis. There are conflicting reports of differing renal allograft outcomes based on the side of donor kidney transplanted (left or right).We sought to determine the effect of side of donor kidney on early and late allograft outcome in our renal transplant population. We performed a retrospective analysis of transplanted left–right deceased donor kidney pairs in Ireland between January 1, 1998 and December 31, 2008. We used a time to death-censored graft failure approach for long-term allograft survival and also examined serum creatinine at different time points post-transplantation. All outcomes were included from day of transplant onwards. A total of 646 transplants were performed from 323 donors. The incidence of delayed graft function was 16.1% in both groups and there was no significant difference in acute rejection episodes or serum creatinine from 1 month to 8 years post-transplantation. There were 47 death-censored allograft failures in the left-sided group compared to 57 in the right-sided group ( P  = 0.24). These observations show no difference in renal transplant outcome between the recipients of left- and right-sided deceased donor kidneys.     

活体肾移植供肾多支血管处理的体会

目的探讨活体肾移植供肾多支血管的处理及重建方法。方法 49例供体,供肾有多支动脉变异45例,有多支静脉变异7例,其中3例为肾动脉、静脉同时多支血管变异。供肾切取术中,对于供血面积直径小于3cm且影响操作的分支动脉,术中即予结扎、离断;多支静脉,如直径为主干的1/3以下且试夹闭该静脉未发现明显淤血等血液回流障碍者,给予结扎、离断。5例采用体外血管重建。受体肾移植术中根据分支动脉管径、长度及位置及受者髂动脉和腹壁下动脉的情况等综合条件来选择受者相应的动脉吻合。结果 48例动脉分支吻合者在开放血流后搏动良好、吻合口通畅,术后1～7d内肾功能恢复正常、术后1～2周彩色多普勒超声检查,提示该分支动脉供血区域丰富。肾静脉分支结扎者未发现淤血现象。1例高龄供肾者发生肾功能延迟恢复。术后无出血、肾动脉栓塞、尿瘘、输尿管坏死和新发高血压等并发症。结论正确处理移植肾多支血管变异,可获得良好移植效果。     

Adverse effect of donor arteriolosclerosis on graft outcome after renal transplantation.

INTRODUCTION: In recent years less strict criteria for renal graft donors have been applied. Our study was designed to investigate whether the histological picture, with special reference to vascular changes of the donor kidney, has an effect on the development and level of graft function, and on 48-month graft survival. METHODS: Three morphologically distinct groups were formed from 150 consecutive cadaveric kidneys donors transplanted into 290 recipients. A control group (C) consisted of kidneys with a completely normal histological picture. Group M1 included kidneys with mild arteriolosclerosis and group M2 (n=122) was comprised of kidneys showing significant arteriolosclerosis. The onset of graft function was assessed by the need for dialysis treatment post-transplantation and the levels of serum creatinine and creatinine clearance at 6, 12, 24 and 36 months post transplant. RESULTS: The proportion of sclerotic glomeruli (P<0.001) and the incidence and severity of interstitial fibrosis was greater in groups M1 and M2 than in the control group (M1, P<0.01; M2, P<0.001). The incidence of vascular fibrinoid necrosis in M2 was greater than in controls (P<0.001). The onset of graft function did not differ significantly between the groups. Group M2 showed a significantly lower level of graft function (P<0.001). The 4-year graft survival rate of group M2 was 74.2%, significantly lower than in the combined group C+M1 (P=0.03). CONCLUSION: Significant vascular lesions in the donor kidney should be taken into account when predicting graft function and survival.     

Fifteen-year follow-up of transplantation of a cadaveric polycystic kidney: a case report

INTRODUCTION: Kidneys from donors affected by autosomal-dominant polycystic kidney disease (ADPKD) are in general considered unsuitable for transplantation. To the best of our knowledge, only 12 cases of ADPKD transplanted renal units have been reported in the English literature; most have only short-term follow-up. METHODS: We provide a review of these patients and share our experience with an ADPKD patient who received a 21-year-old deceased donor ADPKD-affected renal transplant and has been closely followed for 15 years. Based on the current literature, this report is the longest follow-up of a ADPKD donor transplant. RESULTS: Over the 15-year follow-up period, there have been no complications related to the ADPKD-affected donor kidney, including three kidney transplant biopsies. The graft continues to function well with the serum creatinine currently 1.2 mg/dL. Serial axial imaging has demonstrated that the cystic disease has slowly progressed in the donor renal unit, with the largest cyst having only increasing from 1.2 to 2.9 cm in diameter. Metachronous, bilateral laparoscopic nephrectomies of the native kidneys were performed owing to intractable pain from cystic enlargement. CONCLUSIONS: Normal functioning deceased donor kidneys that show signs of early ADPKD should be considered acceptable for donation in select cases. These organs provide the recipient a safe, reasonable period of graft survival and have not been shown to cause adverse effects.     

Hypertension is an independent predictor of delayed graft function and worse renal function only in kidneys with chronic pathological lesions

BACKGROUND: Delayed graft function (DGF) has been identified as one of the principal correlates of poor graft survival in cadaveric renal transplantation. However, its risk factors and clinical predictors have been poorly elucidated. METHODS: We analyzed the risk factors of DGF with a specific emphasis on the role of histological damage of donor kidney. Then, we also studied the impact of DGF, and donor factors affecting DGF, on kidney graft function over the first year after engraftment in 100 consecutive cadaveric renal transplant (Tx) recipients. RESULTS: The organs displaying DGF (n=48) had a significantly higher degree of glomerular sclerosis and tubular atrophy (P<0.01), as well as of interstitial fibrosis and vascular damage (P<0.02) in time-zero biopsies. In patients who received an "ideal" organ for Tx (total histological score < or = 4), DGF showed a strong relationship with Deltaage D-R (70% increase of risk for donors 10 years older than recipients), and with the histological score (odds ratio 1.34). In contrast, donor hypertension was the most relevant variable independently associated with DGF (odds ratio 19.4) in patients receiving a suboptimal organ (histological score >4). Moreover, DGF and donor hypertension adversely affected graft function at 1 year, but only in Tx patients with a histological score >4 in time-zero biopsy. Of note, both patients with and those without DGF showed a very low incidence of biopsy-proven acute rejection (8.5 and 6.8%, respectively) and a rather short cold ischemia time (<16 hr). CONCLUSION: Our findings suggest that the quality of the transplanted organ and the occurrence of DGF are strictly related to each other and can influence graft function through apparently nonimmune mechanisms. In addition, long-standing donor hypertension is a strong independent variable affecting both DGF and graft function of suboptimal cadaveric kidneys, at least up to 1 year.     

Hypertension in solid organ transplant recipients

Hypertension (HT) is one of the most frequent complications of solid organ transplantation; about 70-90% of this population have high blood pressure or require antihypertensive therapy. Abnormal blood pressure is a potent non-immunological risk factor directly related to patient and graft survival. The etiology of hypertension after orthotopic heart transplantation is multifactorial and varies depending on the time following transplantation. In the early period after transplantation, hypertension is generally related to intravascular volume expansion and persistently increased systemic vascular resistance. Other factors predominant in kidney allograft recipients include: donor age, donor familial history of hypertension, transplant renal artery stenosis, graft function, the recurrence or de novo appearance of glomerulonephritis in transplanted kidney, and post-biopsy arteriovenous fistula. In liver and heart transplantation, hypertension is mainly due to impaired kidney function, with all its consequences. Another contributing factor is immunosuppressive regimen based on calcineurin inhibitors and steroids. The management of post-transplant hypertension usually requests non-pharmacological and pharmacological treatment. In this review, the pathogenesis and treatment of post-transplant hypertension in solid organ transplantation is presented.     

Proportion of glomerulosclerosis in procurement wedge renal biopsy cannot alone discriminate for acceptance of marginal donors

BACKGROUND: The shortage of available kidneys for renal transplantation could be addressed, to some extent, by expanding the criteria for acceptance of marginal donors. The study of these criteria is limited by the selection of grafts actually retrieved and transplanted, therefore reduced to a study of risk factors. We have evaluated the potential of procurement renal biopies as an instrument for acceptance or refusal of donor kidneys for transplantation. METHODS: This was a prospective study of a consecutive series of 200 donors. Biopsies were performed by wedge technique at the donor operation and were evaluated for proportion of glomerulosclerosis, vascular and tubular changes, and interstitial fibrosis. The study included 387 renal grafts with a representative biopsy, transplanted, and followed-up for survival and functional evaluation; 24 hr creatinine clearance at 1 and 3 weeks, and 3, 6, 12, 18, and 24 months. RESULTS: Factors associated with initial graft function included cold ischemia time, number of DR mismatches, tubular changes, although donor age showed the strongest correlation with short- and long-term level of graft function. DR mismatches and retransplantation appeared to be the only significant risk factors for graft loss. The proportion of glomerulosclerosis (mean 8%, range 0-48%) correlated with graft function in the simple regression analysis. However, when age was taken into account glomerulosclerosis did not correlate significantly with graft function. Furthermore, glomerulosclerosis as high as 25% or more had an acceptable 3-year graft survival rate of 74.7%. CONCLUSION: Procurement biopsy provides only limited information for the decision whether or not to accept a kidney donor.     

Partial Bladder Transplantation with En Bloc Kidney Transplant—The First Case Report of a 'Bladder Patch Technique' in a Human

Transplantation of the urinary bladder has not been reported in humans. We transplanted a portion of the donor bladder with an en bloc kidney graft in a 12-month-old girl. The child had a congenital hypoplastic single kidney with an ectopic ureteral opening into the vagina. Her native bladder was extremely small. Bilateral kidneys were transplanted en bloc with their ureters connected to a patch of the donor bladder, which encompassed the bilateral ureterovesical junctions (UVJs) (bladder patch technique). Approximately one-third of the donor bladder wall was used. The bladder patch reperfused well via blood supply from the ureters. Posttransplant cystoscopy with retrograde cystogram revealed a viable transplanted bladder with normal emptying of transplanted ureters. No reflux across the donor UVJs was seen in a voiding cystourethrogram. The child is doing well with normal renal function at 18-month follow-up.     

Effect of histological damage on long-term kidney transplant outcome

BACKGROUND: Chronic renal allograft failure remains a major challenge to overcome. Factors such as donor quality, delayed graft function (DGF), acute rejection, and immunosuppression are known to affect long-term outcome, but their relationship to histological damage to graft outcome is unclear. METHODS: Protocol kidney biopsies (n=112) obtained at 3 months after transplantation yielded 102 with adequate tissue. Histology was scored by the Banff schema, and compared with implantation biopsies (n=91), repeat 12-month histology (n=39), decline in serum creatinine and serial isotopic glomerular filtration rate, onset of chronic allograft nephropathy (CAN), and actuarial graft survival censored for death with a functioning graft. RESULTS: At a median follow-up of 9.3 years, 20 patients had graft failure and 26 died with a functioning graft. Banff chronic nephropathy was present in 24% of 3-month biopsies, and was predicted by microvascular disease in the donor, cold ischemia, DGF, and acute vascular rejection (P<0.001). Acute glomerulitis at 3 months correlated with segmental glomerulosclerosis at 12 months, subsequent recurrent glomerulonephritis, and graft failure (P<0.01). Subclinical rejection at 3 months occurred in 29% of biopsies, correlated with prior acute rejection and HLA mismatch, and led to chronic histological damage by 12 months (r=0.25-0.67, P<0.05-0.001). Subclinical rejection, arteriolar hyalinosis, and tubulitis present at 3 months had resolved by 12 months. The 10-year survival rates for Banff chronic nephropathy were 90.4% for grade 0, 81.0% grade 1, and 57.9% for grades 2 or greater (P<0.01). Early tubulointerstitial damage at 3 months profoundly influenced graft survival beyond 10 years. CAN was predicted by kidney ischemia, 3-month chronic intimal vascular thickening, tubular injury, proteinuria, and late rejection. Chronic fibrointimal thickening of the small arteries and chronic interstitial fibrosis at 3 months independently predicted graft loss and decline in renal function (P<0.05-0.001). CONCLUSIONS: Early transplant damage occurs in the tubulointerstitial compartment from preexisting donor kidney injury and discrete events such as vascular rejection and DGF. Subsequent chronic damage and graft failure reflect accumulated previous injury and chronic interstitial fibrosis, vascular impairment, subclinical rejection, and injury from late rejection. CAN may be conceptualized as the sequelae of incremental and cumulative damage to the transplanted kidney. The duration of graft survival is dependent and predicted by the quality of the transplanted donor kidney combined with the intensity, frequency, and irreversibility of these damaging insults.     

Deceased donor renal transplantation--does side matter?

BACKGROUND: The aim of the present study was to determine whether the deceased donor kidney side (left or right kidney) was predictive of subsequent kidney transplant outcomes. METHODS: A retrospective analysis was undertaken of the left-right deceased donor kidney pairs transplanted into recipients with end-stage renal failure in Queensland between 1 April 1994 and 31 March 2004. RESULTS: A total of 201 left-right deceased donor kidney pairs were transplanted into 402 patients. The baseline characteristics of the recipients in the two groups were comparable, except that the patients receiving right kidneys had lower body mass indices and shorter cold ischaemic times. No differences were seen between the left and right kidney recipient groups with respect to operative duration (3.02 +/- 0.67 vs 3.12 +/- 0.72 h, P = 0.16), warm ischaemic time (0.62 +/- 0.18 vs 0.65 +/- 0.21, P = 0.09), delayed graft function (4 vs 6%, respectively, P = 0.26) or a composite vascular, haemorrhagic, ureteric and infective post-operative complication end-point (22 vs 22%, P = 0.90). Estimated glomerular filtration rates were almost identical at 1 month (52.7 +/- 39.6 vs 51.0 +/- 24.0 ml/min/1.73 m(2), P = 0.34) and remained comparable thereafter. Respective death-censored graft survival rates for left and right kidney recipients were 100 and 100% at 1 year, 99.4 and 96.4% at 3 years and 96.3 and 95.5% at 5 years, respectively (P = 0.67). CONCLUSIONS: Although left and right deceased donor kidneys present different operative challenges, the present results suggest that the probability of early post-operative complications, delayed graft function, impaired early and medium-term renal allograft function or death-censored graft failure is comparable between left and right kidney recipients.     

Should we use kidneys from donors with acute kidney injury for renal transplantation?

The scarcity of donor organs for transplant results in long waiting times for kidney transplantation and low transplant rate worldwide. Utilization of kidneys from donors with acute kidney injury (AKI) is one of the strategies that has attracted attention recently. This article reviewed the outcomes of transplanted renal allografts from donors with acute kidney injury. Key findings about the transplant outcomes included a higher incidence of delayed graft function and primary non function, but respectable outcomes in the context of similar acute rejection rates, and graft function and graft survival. Against this background and with evidence of high mortality for patients remaining on waiting list of transplant, we advocate consideration of AKI donors for kidney transplantation.     

Allograft and patient survival after sequential HSCT and kidney transplantation from the same donor—A multicenter analysis

Tolerance induction through simultaneous hematopoietic stem cell and renal transplantation has shown promising results, but it is hampered by the toxicity of preconditioning therapies and graft‐versus‐host disease (GVHD). Moreover, renal function has never been compared to conventionally transplanted patients, thus, whether donor‐specific tolerance results in improved outcomes remains unanswered. We collected follow‐up data of published cases of renal transplantations after hematopoietic stem cell transplantation from the same donor and compared patient and transplant kidney survival as well as function with caliper‐matched living‐donor renal transplantations from the Austrian dialysis and transplant registry. Overall, 22 tolerant and 20 control patients were included (median observation period 10 years [range 11 months to 26 years]). In the tolerant group, no renal allograft loss was reported, whereas 3 were lost in the control group. Median creatinine levels were 85 μmol/l (interquartile range [IQR] 72‐99) in the tolerant cohort and 118 μmol/l (IQR 99‐143) in the control group. Mixed linear‐model showed around 29% lower average creatinine levels throughout follow‐up in the tolerant group (P < .01). Our data clearly show stable renal graft function without long‐term immunosuppression for many years, suggesting permanent donor‐specific tolerance. Thus sequential transplantation might be an alternative approach for future studies targeting tolerance induction in renal allograft recipients.     

Trasplante renal mediante reconstrucción de conducto vascular en riñones de donantes fallecidos con arterias renales múltiples y venas renales cortas

BackgroundTransplantation of kidneys with vascular anatomical variants remains a challenge. Due to its varying success in regard to graft function after transplantation, these organs have been frequently discarded assuming in advance an unaffordable rate of vascular complications.Patients and methodsWe performed three kidney transplants using organs from deceased donors harboring vascular variants (multiple arteries and short veins), including an unsplittable horseshoe kidney. Different grafts harvested from the same donor aorta, common iliac artery, and inferior vena cava, were used to reconstruct the initial vascular configuration by creating single arterial and venous conduits aimed to simplify the vascular anastomoses in the recipient.ResultsNo post-operative complications were recorded. Warm ischemia times remained comparable to single artery renal allografts. No delayed graft function was noted in any case, and every patient regained normal renal function after transplantation.ConclusionsVascular reconstruction using arterial and venous grafts harvested from the same deceased donor may result a helpful tool to simplify vascular anastomoses during transplantation surgery, thus avoiding their discard in advance, minimizing perioperative complications, and enabling normal graft function rates in the long-term follow-up. The successful outcome obtained by using this approach would help to expand the donor criteria for the inclusion of organs containing vascular anatomical variants.