Management of deceased and living kidney donor with lithiasis: a multicenter retrospective study on behalf of the renal transplant group of the Spanish urological association.

BACKGROUND: To maximize the availability of suitable grafts and ensure effective management, several reports have demonstrated successful outcomes when using kidney grafts with urolithiasis. This multicenter study reports on the management and long-term outcomes of kidney transplantation using renal grafts with lithiasis. METHODS: Retrospective data from three Spanish hospitals were analyzed for kidney transplants involving grafts with nephrolithiasis performed between December 2009 and August 2023. The study included adult patients, excluding those with incomplete records. It evaluated stone characteristics, complications, and outcomes in recipients and in living kidney donors. RESULTS: Out of 38 analyzed kidney transplants, 57.9% were cadaveric and 42.1% were from living kidney donors. Most diagnoses were incidental during donor evaluation, with an average stone size of 7.06 mm. After follow-up (median 26 months), all recipients but one had functioning grafts, and there were no stone recurrences in both recipients and living kidney donors. Conservative management was adopted in 28 cases, while 10 cases required ex-vivo flexible ureterorenoscopy for stone removal. Following conservative management, 5 patients needed additional treatments for stone-related events. CONCLUSIONS: Kidneys with lithiasis can be considered for transplantation in selected cases, resulting in good functional outcomes with no stone recurrence in recipients or living donors.

Living donor-gifted allograft lithiasis: surgical experience after bench surgery stone removal and follow-up.

This study presents the surgical experience and long-term outcomes of living donor kidney transplantations involving asymptomatic kidney stones, using ex vivo flexible ureterorenoscopy (f-URS) during bench surgery for stone removal. Out of 1743 living kidney donors assessed between January 2012 and October 2022, 18 (1%) were diagnosed with urolithiasis. Among them, 12 donors were rejected, and 6 were accepted for kidney donation. Stone removal was successfully performed using f-URS during bench surgery, with no immediate complications or acute rejections observed. The study analyzed six living kidney transplants, of which 4 (67%) donors and three recipients were female, and 4 (67%) donors were blood-related to the recipient. The median age for donors and recipients was 57.5 and 51.5 years, respectively. The stones, primarily located in the lower calyx, had a median size of 6 mm. The median cold ischemia time during surgery was 41.6 min, and ex vivo f-URS ensured complete stone removal in all cases. After a median follow-up of 120 months, the remaining grafts were functioning well, and no urinary stone recurrence was observed in either the recipients or living donors. The findings suggest that bench f-URS is a safe approach for managing urinary stones in kidney grafts, providing good functional outcomes without stone recurrence in selected cases.

The evolution of CT diagnosed papillae tip microcalcifications: can we predict the development of stones?

OBJECTIVES: To determine the incidence of computed tomography (CT) identifiable Randall plaques in a CT explored population; to determine the clinical relevance of this radiological finding by a 7-year follow-up; to determine a cut point to identify a population with high risk of developing calcium stone disease (SD). MATERIALS AND METHODS: Retrospective study of all patients explored by abdominal CT in our center between January and March 2005. INCLUSION CRITERIA: age 30-60 years and no SD. Papillae attenuation was measured on nonenhanced CT in Hounsfield units (HU) and the mean of all papillae was calculated. Patients were re-evaluated after 7 years to identify calcium stone formers. Anamnesis and already available CT, ultrasound, kidney, ureter, and bladder radiograph (KUB) or intravenous urography (IVU) images performed as part of their follow-up were used. In patients with no follow-up, ultrasound and KUB were to be performed. Pearson correlation, Student t-test, and the receiver operator curve were used for statistical analysis. RESULTS: A total of 362 patients fulfilled the inclusion criteria and were analyzed; 12 developed calcium SD after 7 years. A significant difference was encountered between the papillae attenuation of stone formers (SF) versus non-SF (47.2HU vs. 35.5HU, p=0.001). There was good correlation between papillae attenuation and the possibility of developing SD (R=0.87). An optimal cut point of 43HU with a sensitivity of 81% and specificity of 97%, area under the curve 0.91, separated SF and non-SF. CONCLUSION: Patients with high papillae density have a higher risk of developing SD. A cut point of 43HU could accurately be used to identify a high-risk population.

Abdominal computed tomography--a new tool for predicting recurrent stone disease.

PURPOSE: To evaluate whether CT-identified Randall plaques can be used to foresee the recurrence of stone disease (SD); to define a cut point that could identify a high-risk population. MATERIALS AND METHODS: A retrospective study of patients attended for SD from January 2004 to December 2009 was conducted. Study population was patients with a first episode of calcium SD that was diagnosed by abdominal CT. Papillae tip attenuation was measured in Hounsfield units (HU) on unenhanced abdominal CT images. Patients with recurrent SD were identified; t test, Pearson correlation, and receiver operating characteristic (ROC) curve analysis were used. RESULTS: A total of 543 patients were evaluated; 187 fulfilled the criteria and were included, and 49 (26.2%) had recurrent SD. Mean follow-up: 5 years (3-7 years). Papillae tip attenuation was significantly higher in the recurrent group (46.2 HU vs 40.1 HU, P=0.01) and correlated well with the possibility of developing SD (R=0.83). Attenuation >43 HU showed a ROC curve area under the curve=0.87 with sensitivity=77% and specificity=84% separating patients with a RR=8.7 of development of recurrent SD. The number of papillae >43 HU correlated with recurrent SD (RR=11.2 for ≥3 papillae vs <3 papillae with density >43 HU). CONCLUSIONS: The presence of the Randall plaques can be used as a marker for predicting SD recurrence. A cut point of 43 HU could be used to identify a high-risk population.