Presented by: Luigi Candela MD
Division of Experimental Oncology/Unit of Urology, URI, IRCCS Ospedale San Raffaele, Milan, Italy. Università Vita-Salute San Raffaele, Milan, Italy

Introduction

Patients suffering from cystinuria experience high stone recurrence rate which results in a considerable number of surgical interventions during lifetime. These patients are at higher risk of developing early chronic kidney disease compared to other urinary stone formers and general population. To improve renal prognosis, non-invasive urological interventions should be preferred to manage stone recurrences. We sought to evaluate long-term renal function modification of cystinuric patients exclusively treated with retrograde ureteroscopy (URS) and Holmium:YAG or Thulium fiber laser lithotripsy. 

Materials

Data from 112 cystinuric patients treated for ureteral/renal stones from 2001 to 2021 at a single academic referral centre were retrospectively analysed. Stone analysis confirmed the diagnosis of cystinuria. Estimated Glomerular Filtration Rate (eGFR) was calculated using the first and the last available serum creatinine level according to the Modification of Diet in Renal Disease (MDRD) formula. Chronic Kidney Disease (CKD) stage was assessed according to the National Kidney Foundation (NKF) classification. Severe CKD was defined as CKD stage ≥3 (i.e. eGFR < 60 ml/min). Regular nephrological management (NM) was defined as 1 nephrological consultation every 12-18 months, according to our internal protocol. Descriptive statistics were used to analyse the cohort data. 

Results

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Complete data including serum creatinine levels of 46 cystinuric patients exclusively treated with URS were available. Median (IQR) age at diagnosis and at first URS in our centre were 18 (10-26) and 32 (22-46) years, respectively. Twenty-eight (60.8%) patients were male, and 13 (28%) patients had a CCI ≥ 1. Median (IQR) follow-up was 101 (70—146) months. Median (IQR) interval between the first and the last available creatinine level was 64 (45-78) months. Median (IQR) number of fURS and recurrences during FU were 6 (3.75-10.25) and 2.5 (1-4), respectively. At the end of follow-up, 18 (39%) patients were stone-free. Thirty-nine (85%) patients had at least 1 nephrological consultation in our center and 19 (43%) had regular NM during follow-up. Median (IQR) first and last eGFR were 72 (57-97.5) and 74 (66-88) mL/min, respectively. Eight (17%) and 5 (10.8%) patients had severe CKD at the beginning and the end of the follow-up, respectively. Overall, 40 (87%) patients had stable or improved renal function within the follow-up.

Conclusion

Severe CKD is a not neglectable complication that occurs in more than 1 out 6 cystinuric patients at an early stage of life. However, most of patients treated conservatively with URS in a referral center have stable or improved renal function within a long-term follow-up. Current findings should be considered for the surgical management of cystinuric patients.

Funding

none

Co-Authors

Eugenio Ventimiglia, MD
Università Vita-Salute San Raffaele, Milan, Italy

Marie Chicaud, MD
Urology Unit, Tenon Hospital, Paris, France

Catalina Solano, MD
Urology Unit, Tenon Hospital, Paris, France

Stessy Kutchukian, MD
Urology Unit, Tenon Hospital, Paris, France

Mariela Corrales, MD
Urology Unit, Tenon Hospital, Paris, France

Luca Villa, MD
Università Vita-Salute San Raffaele, Milan, Italy

Frederic Panthier, MD
Urology Unit, Tenon Hospital, Paris, France

Steeve Doizi, MD
Urology Unit, Tenon Hospital, Paris, France

Emmanuel Letavernier, MD
Nephrology Unit, Tenon Hospital, Paris, France

Jean Philippe Haymann, MD
Nephrology Unit, Tenon Hospital, Paris, France

Michel Daudon, MD
Nephrology Unit, Tenon Hospital, Paris, France

Francesco Montorsi, MD
Università Vita-Salute San Raffaele, Milan, Italy

Salonia Andrea, MD
Università Vita-Salute San Raffaele, Milan, Italy

Olivier Traxer, MD
Urology Unit, Tenon Hospital, Paris, France