Transplantation of Reconstructed Renal Allografts Following Ex-Vivo Partial Nephrectomy

Inclusion criteria

For Donors:

• Adults > 50 years
• Willing and able to understand and sign informed consent
• Must have high-quality pre-operative cross-sectional imaging (CT or MRI) to determine tumor characteristics and perform parenchymal volume analysis for split renal function
• Patient who is a candidate for partial nephrectomy for cT1a mass who understands that partial nephrectomy is standard of care for such mass but wishes to be an altruistic kidney donor (primary incentive is altruism) via radical nephrectomy with loss of the entire kidney.
• Functional considerations:

o Normal baseline renal function, with eGFR > 80 ml/min/1.73 m2

• No proteinuria on urine dipstick (negative/trace considered negative)
• Predicted new baseline GFR (NBGFR) following radical nephrectomy would be ≥ 45
• NBGFR would be calculated using previously described equation based on split renal function (SFR) and renal functional compensation (RFC)
• NBGFR = global GFR x (SRFcontralateral from PVA) x 1.25 (average amount of RFC)2
• Tumor characteristics on pre-operative cross-sectional imaging:

• Tumor appears well-encapsulated
• Tumor appears amenable to ex-vivo partial nephrectomy with reconstruction that will leave ≥75% of the functioning parenchyma intact and well vascularized
• Low risk of complications for the recipient after ex-vivo PN based on surgeon judgment
• Tumor is cT1a which is defined as ≤ 4cm and confined
• Reconstructed kidney is likely to provide NBGFR for the recipient of >30 ml/min/1.73 m2. This can be estimated as (global GFR)(SRFipsilateral) x 0.75(estimate that at least 75% of the function will be saved during ex vivo tumor excision and reconstruction). Of note most such kidneys will experience some positive functional compensation but this might be mitigated by a small amount of functional loss related to ischemia. Most studies suggest that this will really be an underestimate of the final GFR in the recipient.

For Recipients:

• Age >60
• Able to understand and willing to sign informed consent
• Presence of ESRD or CKD5 with likely progression to ESRD
• Does not have potential living donor
• Not likely to receive a more "ideal" donor kidney due to significant comorbidities and/or age

Exclusion criteria

For Donors:

• Known familial RCC syndrome
• Functional considerations:

o < 50 years of age

• Preoperative GFR < 80 ml/min/1.73 m2
• Proteinuria on urine dipstick or urinalysis (≥1+ considered positive)
• Predicted new baseline GFR (NBGFR) following radical nephrectomy would be < 45
• NBGFR would be calculated using previously described equation based on split renal function (SFR) and renal functional compensation (RFC)
• NBGFR = global GFR x (SRFcontralateral from PVA) x 1.25 (average amount of RFC)2
• Comorbidities with risk of deteriorating renal function:

• Hypertension requiring three or more anti-hypertensives
• Diabetes mellitus requiring insulin or with end organ damage
• Morbid obesity
• History of nephrolithiasis or other
• Tumor characteristics on pre-operative cross-sectional imaging:

o Tumor has infiltrative features

• Tumor is > 4cm (does not meet criteria for cT1a stage)
• Regional lymphadenopathy, branch or main renal vein invasion, or other imaging findings suggestive of locally advanced disease
• Kidney characteristics on pre-operative cross-sectional imaging:

• More than one renal artery unless can be readily and safely reconstructed
• More than one renal vein unless can be readily and safely reconstructed
• Duplicated collecting system unless can be readily and safely reconstructed
• High-risk features on renal mass biopsy (if obtained) or intraoperative pathology

o Malignant non-RCC pathology

o Rhabdoid or sarcomatoid differentiation

o Grade 4

o Positive or concerning margins during tumor excision

• Must be deemed appropriate living donor candidate per the standard living donor selection process at the Cleveland Clinic o All altruistic living donors undergo a complete evaluation by medical providers and social workers ensuring that they are appropriate candidates to undergo this procedure. This evaluation includes direct query into any history of psychiatric comorbidities and/or substance abuse. If present, this prompts a formal evaluation by psychiatry prior to confirmation of donor candidacy.

For Recipients:

• Traditional contraindications to kidney transplantation at the Cleveland Clinic would apply, including the following directly from the Transplant Care Pathway:

• Active, untreated bacterial, fungal, or viral infections. Once treated, patients may be reconsidered. Patients with human immunodeficiency virus (HIV)14 or chronic hepatitis15 infections will be evaluated on an individual basis.
• Active malignancy, except non-melanoma skin cancer and other selected low-grade, low-stage cancers (e.g., bladder, kidney, prostate). The American Society of Transplant (AST) clinical practice guidelines published in 2001 are dated. Improved methods of cancer prognostication are available on a cancer-specific basis.16 An acceptable disease-free waiting period may be needed prior to transplantation depending on the cancer type (stage/grade) and treatment modality. Expert opinion from an oncological specialist may be needed to facilitate decisions about wait-listing or performance of a transplant.
• Medical non-adherence, substance abuse or behaviors leading to a failure to achieve a therapeutic physician/transplant team-patient alliance.
• Life expectancy of less than five years independent of renal disease.
• Advanced circulatory disease (cardiac, cerebral, peripheral), pulmonary disease or other non-renal conditions such that transplantation would pose a significant risk for morbidity/mortality.
• Obesity with body mass index (BMI) > 38, or an abdominal wall configuration that in the judgment of the evaluating surgeon poses undue complication risk.
• Active nicotine abuse (in any form).
• Poor functional status independent of renal disease.
• Considering the average waiting times for a deceased donor kidney is more than 3 years, only transplant candidates 72 years or younger will be accepted for evaluation. Suitable candidates may remain on the waiting list up to the age of 75-year-old. They will be delisted if no transplantation has occurred.
• Cumulative burden of disease defined as multiple medical conditions that on their own may not preclude listing but that in combination are deemed not suitable by the transplant selection committee.