Computerized tomographic angiography for renal donor evaluation leads to a higher exclusion rate

Association between donor kidney cysts and donor and recipient outcomes after living donor kidney transplantation

INTRODUCTION

Incidental kidneys cysts are typically considered benign, but the presence of cysts is more frequent in individuals with other early markers of kidney disease. We studied the association of donor kidney cysts with donor and recipient outcomes after living donor kidney transplantation.

METHODS

We retrospective identified 860 living donor transplants at our center (1/1/2011-7/31/2022) without missing data. Donor cysts were identified by review of pre-donation CT scan reports. We used linear regression to study the association between donor cysts and 6-month single-kidney estimated glomerular filtration rate (eGFR) increase, and time-to-event analyses to study the association between donor cysts and recipient death-censored graft failure.

RESULTS

Among donors, 77% donors had no kidney cysts, 13% had ≥1 cyst on the kidney not donated, and 11% only had cysts on the donated kidney. In adjusted linear regression, cysts on the donated kidney and kidney not donated were not significantly associated with 6-month single-kidney eGFR increase. Among transplants, 17% used a transplanted kidney with a cyst and 6% were from donors with cysts only on the kidney not transplanted. There was no association between donor cyst group and post-transplant death-censored graft survival. Results were similar in sensitivity analyses comparing transplants using kidneys with no cysts versus 1-2 cysts versus ≥3 cysts.

CONCLUSIONS

Kidney cysts in living kidney donors were not associated with donor kidney recovery or recipient allograft longevity, suggesting incidental kidney cysts need not be taken into account when determining living donor candidate suitability or the laterality of planned donor nephrectomy.

Clinical features and prognostic impact of asymptomatic pancreatic cancer

Pancreatic ductal adenocarcinoma (PDAC) is highly lethal, and early diagnosis is challenging. Because patients who present with symptoms generally have advanced-stage diseases, analysis of asymptomatic PDAC provides invaluable information for developing strategies for early diagnosis. Here, we reviewed 577 patients with PDAC (372 diagnosed with symptoms [symptomatic group] and 205 without symptoms [asymptomatic group]) diagnosed at our institute. Among the 205 asymptomatic PDAC patients, 109 were detected during follow-up/work-up for other diseases, 61 because of new-onset or exacerbation of diabetes mellitus, and 35 in a medical check-up. Asymptomatic PDAC is characterized by smaller tumor size, earlier disease stage, and higher resectability than those of symptomatic PDAC. In 22.7% of asymptomatic cases, indirect findings, e.g., dilatation of the main pancreatic duct, triggered PDAC detection. Although pancreatic tumors were less frequently detected, overall abnormality detection rates on imaging studies were nearly 100% in asymptomatic PDAC. Asymptomatic PDAC had a better prognosis (median survival time, 881 days) than symptomatic PDAC (342 days, P < 0.001). In conclusion, diagnosis of PDAC in the asymptomatic stage is associated with early diagnosis and a better prognosis. Incidental detection of abnormal findings during the follow-up/work-up for other diseases provides important opportunities for early diagnosis of asymptomatic PDAC.

Differences in national and international guidelines regarding use of kidney stone formers as living kidney donors

PURPOSE OF REVIEW

Traditionally, nephrolithiasis was considered a relative contraindication to kidney donation because of a risk of recurrent stones in donors and adverse stone-related outcomes in recipients. However, the scarcity of organs has driven the transplant community to re-examine and broaden selection criteria for living donors with stones. In this review, we summarize and contrast the guidelines published by various prominent national and international societies on this topic.

RECENT FINDINGS

Although recent iterations of living donor guidelines are less stringent with respect to nephrolithiasis than those published in the 1990s, there is little consensus among national and international transplant society guidelines regarding selection criteria for potential kidney donors with nephrolithiasis.

SUMMARY

The lack of evidence-based guidelines deters transplant centers from implementing selection criteria to accept donors with nephrolithiasis and discourages studies of outcomes in donors with nephrolithiasis and their recipients. In addition to drawing attention to the disparities in prevailing guidelines, we put forth several questions that must be answered before generalizable criteria for selection of donor with nephrolithiasis can be developed.

Prevalence of Incidental Findings on Multidetector Computed Tomography in Potential Nephrectomy Donors: A Prospective Observational Study

OBJECTIVES

Prospective renal donors are a select population of healthy individuals who have been thoroughly screened for significant comorbidities before they undergo multidetector computed tomography. Our aim was to determine the prevalence of incidental findings on preoperative multidetector computed tomography in a healthy cohort of potential living donors for kidney transplant.

MATERIALS AND METHODS

A prospective study was performed of prospective living kidney transplant donors at a national kidney transplant center. Study inclusion criteria were all potential kidney donors who underwent multidetector computed tomography during the living-donor assessment process over a 5-year period (January 2012 to 2017).

RESULTS

Our cohort included 375 potential living donors who had multidetector computed tomography; mean age was 44.33 years (range, 21-71.5 y). In total, there were 228 incidental findings identified in 158 individuals. Of the 375 potential donors, 193 (51%) proceeded to living donor nephrectomy. On multidetector computed tomography, 97 incidental findings were identified in the donor cohort versus 131 in the cohort that did not proceed to donation. Bosniak 1 renal cysts were the most common incidental finding (n = 46) followed by liver cysts < 1.5 cm (n = 42) and urinary tract calculi (n = 21). There was 1 incidentally detected pathologically proven malignancy.

CONCLUSIONS

A variety of incidentally detected lesions of moderate to high importance were detected in this healthy donor cohort. Individuals undergoing assessment with multidetector computed tomography for living donor nephrectomy should be counseled on medical, financial, and psychological implications of incidentally detected lesions during the kidney transplant evaluation process.

Computed tomography identified factors that preclude living kidney donation

INTRODUCTION

The purpose of this study was to determine the variety and prevalence of renal and non-renal abnormalities detected on multidetector computed tomography (MDCT) that precluded patients from donating a kidney.

METHODS

Institutional review board approval was obtained and the requirement for informed consent was waived. A retrospective, single-centre review of 701 patients (444 female, 257 male; age range 18-86 years; mean age 43.2±11.9 years) that underwent renal donor protocol MDCT was conducted. A systematic review of the CT report, records from multidisciplinary renal transplantation rounds, and electronic medical records was performed to determine which patients were approved or declined as live renal donors. If declined as a donor, CT-identified reasons were categorized as abnormalities of renal vasculature, renal parenchyma, collecting system, or extra-renal.

RESULTS

A total of 81 patients were excluded as renal donors on the basis of CT findings. Abnormalities of the collecting system accounted for the most frequent cause of exclusion (n=41), with asymptomatic renal calculi being detected in 39 patients. Complex vascular anatomy and vascular abnormalities resulted in the exclusion of 29 patients. Supernumerary arteries and early arterial branching resulted in the exclusion of 20 patients, while renal vein anomalies leading to exclusion were uncommon (n=2). Abnormalities of renal parenchyma resulted in the exclusion of nine patients. Three patients were diagnosed with autosomal dominant polycystic kidney disease, two patients had renal cell carcinoma, and two patients had areas of cortical scarring. A complex cystic lesion requiring surveillance imaging was encountered in one patient and a large area of renal infarction related to prior adrenalectomy was demonstrated in one patient. Extra-renal abnormalities leading to exclusion were limited to two patients with pulmonary nodules.

CONCLUSIONS

MDCT plays a critical role in the preoperative assessment of potential renal donors by identifying contraindications to donor nephrectomy and providing accurate vascular mapping. This study is anticipated to be informative for those involved in the workup of potential living renal donors by quantifying the incidence and reasons for donor exclusion identified on CT.

Evaluation of Deceased Kidney Donors for Renal Stone Disease: Is Computed Tomography Needed?

Objective

To investigate the clinical consequences of neglected risk of urolithiasis in deceased kidney donors in routine clinical practice, this study focused on different management options for transplanted allograft stones, and tried to find new solutions for more accurate detection of urolithiasis in deceased kidney donors prior to renal transplantation.

Methods and Results

The overall prevalence of stone disease in endemic countries is between 7 and 29%. Because of the increased risk for stone disease in epidemic countries, screening renal grafts from deceased donors necessitates more sensitive imaging tests. Despite well established procedures on preoperative living related renal donor evaluation, there is no consensus on a preoperative imaging tool in cadaveric renal donor evaluation. The most commonly used imaging modality in deceased renal donors is ultrasonography. The overall sensitivity and specificity of ultrasonography for kidney stones are 45 and 88%, respectively. Use of a computed tomography scan for renal diseases, especially for urinary stones is now almost a routine test in clinical practice. Its sensitivity for renal stones < 3 mm is 85%, whereas for renal stones > 3 mm it is 100%.

Conclusion

The use of radiological modalities i.e. computed tomography with higher sensitivity in deceased donors prior to renal transplantation seems reasonable in urinary stone epidemic countries.

Role of MDCT angiography in selection and presurgical planning of potential renal donors

OBJECTIVE

The purpose of this study was to determine the prevalence and types of renal and extrarenal abnormalities that preclude renal donation or lead to alteration of the surgical approach on the basis of abdominal CT angiography (CTA) in a large group of potential renal donors.

MATERIALS AND METHODS

In this retrospective study, 654 potential renal donors undergoing dual-phase CTA were identified from January 2005 to January 2009. The CT reports were systemically reviewed by two radiologists to determine the presence of renal and extrarenal abnormalities. The operative notes of the renal donors were reviewed by one radiologist to determine whether the presence of renal pathology had affected the surgical approach. In the candidates who did not proceed to kidney donation, the reasons that precluded kidney donation were abstracted from the transplant database.

RESULTS

Four hundred seventeen potential donors (269 men and 385 women; mean age, 44.0 years; age range, 17-79 years) proceeded to renal donation and 237 did not. The most common renal abnormalities were cysts (34%) and renal stones (4.4%). Renal artery disease was identified in 3.4% of potential donors, including renal artery stenosis, possible fibromuscular dysplasia, and renal artery aneurysm. Suspicious renal masses were incidentally found in 0.5% of potential donors. The most common extrarenal pathology was an incidental adrenal nodule (2.6%). Other significant extrarenal pathology identified included gallbladder mass (0.2%), Crohn disease (0.2%), ovarian mass (0.2%), and possible sarcoidosis (0.2%). Although renal and extrarenal abnormalities were present in 41% of potential renal donors, abnormalities seen on CT only contributed to exclusion of 27 potential donors (4.1%). The most common reason for exclusion was the presence of renal stones or scarring (1.8%). Significant CT findings also contributed to the selection of the right kidney in 29 donors, most commonly due to presence of ipsilateral vascular disease or complex left vascular anatomy.

CONCLUSION

Renal parenchymal and vascular abnormalities are common in asymptomatic potential kidney donors. Although most of these represent incidental CT findings, abnormalities can exclude potential renal donors and alter the surgical approach in a small minority of cases.

Controversies related to living kidney donors

Background

Increasing the living-donor pool by accepting donors with an isolated medical abnormality (IMA) can significantly decrease the huge gap between limited supply and rising demand for organs. There is a wide range of variation among different centres in dealing with these categories of donors. We reviewed studies discussing living kidney donors with IMA, including greater age, obesity, hypertension, microscopic haematuria and nephrolithiasis, to highlight the effect of these abnormalities on both donor and recipient sides from medical and surgical perspectives.

Methods

We systematically searched MEDLINE, ISI Science Citation Index expanded, and Google scholar, from the inception of each source to January 2011, using the terms ‘kidney transplant’, ‘renal’, ‘graft’, ‘living donor’, ‘old’, ‘obesity’, ‘nephrolithiasis’, ‘haematuria’ and ‘hypertension’. In all, 58 studies were found to be relevant and were reviewed comprehensively.

Results

Most of the reviewed studies confirmed the safety of using elderly, moderately obese and well-controlled hypertensive donors. Also, under specific circumstances, donors with nephrolithiasis can be accepted. However, persistent microscopic haematuria should be considered seriously and renal biopsy is indicated to exclude underlying renal disease.

Conclusion

Extensive examination and cautious selection with tailored immunosuppressive protocols for these groups can provide a satisfactory short- and medium-term outcome. Highly motivated elderly, obese, controlled hypertensive and the donor with a unilateral small stone (<1.5 cm, with normal metabolic evaluation) could be accepted. Donors with dysmorphic and persistent haematuria should not be accepted. A close follow-up after donation is crucial, especially for obese donors who developed microalbuminuria.

Chronic kidney disease in kidney stone formers

Recent population studies have found symptomatic kidney stone formers to be at increased risk for chronic kidney disease (CKD). Although kidney stones are not commonly identified as the primary cause of ESRD, they still may be important contributing factors. Paradoxically, CKD can be protective against forming kidney stones because of the substantial reduction in urine calcium excretion. Among stone formers, those with rare hereditary diseases (cystinuria, primary hyperoxaluria, Dent disease, and 2,8 dihydroxyadenine stones), recurrent urinary tract infections, struvite stones, hypertension, and diabetes seem to be at highest risk for CKD. The primary mechanism for CKD from kidney stones is usually attributed to an obstructive uropathy or pyelonephritis, but crystal plugs at the ducts of Bellini and parenchymal injury from shockwave lithotripsy may also contribute. The historical shift to less invasive surgical management of kidney stones has likely had a beneficial impact on the risk for CKD. Among potential kidney donors, past symptomatic kidney stones but not radiographic stones found on computed tomography scans were associated with albuminuria. Kidney stones detected by ultrasound screening have also been associated with CKD in the general population. Further studies that better classify CKD, better characterize stone formers, more thoroughly address potential confounding by comorbidities, and have active instead of passive follow-up to avoid detection bias are needed.

Prevalence of urolithiasis in asymptomatic adults: objective determination using low dose noncontrast computerized tomography

PURPOSE

The true prevalence of urolithiasis in asymptomatic adults is unknown. Unenhanced computerized tomography represents the gold standard for detection. We evaluated the prevalence and symptomatic incidence of urolithiasis in a large cohort of asymptomatic adults using noncontrast computerized tomography.

MATERIALS AND METHODS

Low dose noncontrast computerized tomography was performed in 5,047 consecutive asymptomatic adults (mean age 56.9 years, 2,747 women and 2,300 men) between 2004 and 2008. Presence, size and location of urinary calculi were recorded. Screening prevalence as well as the incidence of symptomatic stone disease during a 10-year interval (1997 to 2007) was compared against previously established clinical risk factors.

RESULTS

The screening prevalence of asymptomatic urolithiasis was 7.8% (395 of 5,047 adults) with an average of 2.1 stones per case (range 1 to 29) and a mean stone size of 3.0 mm (range 1 to 20). During a 10-year period 20.5% (81 of 395) of patients with stones (1.6% of entire screening cohort) had at least 1 symptomatic episode. Males were more likely to have urolithiasis than females (9.7% vs 6.3%, p <0.001). Diabetes (9.0% vs 7.7%, p = 0.45), obesity (7.6% vs 7.9%, p = 0.72) and age 60 years or older (8.0% vs 7.7%, p = 0.73) did not affect prevalence, but diabetes and obesity did correlate with symptom development (p <0.001 and p <0.05, respectively).

CONCLUSIONS

This objective population based assessment in a large asymptomatic cohort showed an 8% prevalence of urolithiasis. Most cases were unsuspected and remained asymptomatic. Although there was no correlation between asymptomatic urolithiasis and diabetes, obesity or older age, diabetes and obesity were associated with a higher incidence of symptoms over time.

Prevalence of renal artery and kidney abnormalities by computed tomography among healthy adults

BACKGROUND AND OBJECTIVES

Management of incidental renal artery and kidney abnormalities in patients undergoing computed tomography scans is a clinical challenge because their frequency in healthy subjects has not been precisely estimated. Therefore, the prevalence and management of these abnormalities were determined among a large cohort of potential kidney donors undergoing protocol evaluations.

DESIGN, SETTING, PARTICIPANTS, & MEASUREMENTS

All patients at the Mayo Clinic who underwent computed tomographic angiography and urography as part of their kidney donor evaluation between 2000 and 2008 were identified. Radiographic reports were abstracted for abnormalities of the renal arteries and kidneys. The prevalence of radiographic abnormalities was stratified by age and gender, and the effect on approval for kidney donation was determined.

RESULTS

Among 1957 potential kidney donors, the mean +/- SD age was 43 +/- 12 years, and 58% were women. The most common abnormalities were kidney stones (11%), focal scarring (3.6%), fibromuscular dysplasia (2.8%), and other renal artery narrowing or atherosclerosis (5.3%). Fibromuscular dysplasia, focal scarring, parenchymal atrophy, and upper tract dilation were more common in women. Renal artery narrowing, focal scarring, and indeterminate masses increased with age. Overall, 25% of potential donors had at least one abnormality. However, these incidental radiographic abnormalities contributed to exclusion from donation in only 6.7% of potential donors.

CONCLUSIONS

Incidental radiographic abnormalities of the renal arteries and kidneys are common. The majority of imaging findings are not perceived to be harmful enough to prevent kidney donation, but future studies are needed to determine their clinical relevance.

Can value for money be improved by changing the sequence of our donor work-up in the living kidney donor programme?

The aim of the study was to identify procedures of maximum importance for acceptance or rejection of kidney donation from a living donor as well as making the process more cost-effective. We identified all potential living related donors who were examined during the period between January 2002 and December 2006 at our department. The cost in euro (euro) for the programme was estimated using the Danish diagnosis-related group-system (DRG). The donor work-up programme was described. One hundred and thirty-three potential donors were identified; 66 male- and 67 female subjects, median age of 52 years (range 22-69). Sixty-four participants were rejected as donors. Abdominal CT-scan with angiography and urography ruled out 22 of the above 64 potential organ donors; thus, 48% of the volunteers for living kidney donation were unsuited for donation. Abdominal CT-scan with angiography and urography was the procedure identifying most subjects who were unsuited for kidney donation. A rearrangement of the present donor work-up programme could potentially reduce the costs from euro6911 to euro5292 per donor--saving 23% of the costs. By changing the sequence of examinations, it might be possible to cut down on time spent and number of tests needed for approving or rejecting subjects for living kidney donation.

Living renal donor allograft lithiasis: a review of stone related morbidity in donors and recipients

PURPOSE

The use of screening computerized tomography angiography has resulted in the increased detection of incidental nephrolithiasis in potential living renal donor candidates. We reviewed current acceptance guidelines for donors with stone disease as well as data on stone related outcomes in donors with stone disease and recipients who received a kidney with a stone left in situ.

MATERIALS AND METHODS

We performed a medical literature search in English using MEDLINE/PubMed that addressed renal donor allograft lithiasis. We then analyzed the literature with respect to the historical evolution of this concept, current guidelines regarding the acceptance of donors with stones and stone related morbidity in recipients and donors.

RESULTS

The prevalence of asymptomatic solitary nephrolithiasis has increased with the widespread use of screening computerized tomography angiography during renal donor evaluation. Few studies have addressed the risk of stone related morbidity in donors and recipients. Short-term studies have shown little stone related morbidity in patients who donate or receive an allograft with a stone left in situ. Consensus statements from transplant societies around the world offer guidance for determining donor eligibility.

CONCLUSIONS

The available literature on stone related morbidity in donors and recipients is extremely limited. It would appear that the risk of recurrence and subsequent morbidity in renal donors with a solitary kidney is low but not insignificant. Rare stone related adverse events are reported for recipients of an allograft with a stone left in situ. Renal donors and recipients should be educated regarding their unique risk perspectives. Long-term followup is mandatory.