Antegrade treatment approaches may yield the highest stone-free rates for patients with de novo nephrolithiasis in kidney grafts, according to new study findings.
In a systematic review of 37 retrospective studies, investigators identified 553 patients with de novo stones in the transplanted kidney. Of the 612 procedures, 20 were antegrade ureteroscopy, 154 retrograde ureteroscopy, 118 percutaneous nephrolithotomy (PCNL), 25 open surgery, 155 extracorporeal shock wave lithotripsy (ESWL), and 140 surveillance/medical treatment. The stone-free rate at 3 months was 96% with open surgery, 95% with antegrade ureteroscopy, 86% with PCNL, 81% with retrograde ureteroscopy, and 75% with ESWL, Alberto Breda, MD, of University Autonoma of Barcelona in Spain, and colleagues reported in European Urology Focus.
“As opposed to the management of nephrolithiasis in native kidney, an antegrade approach should be considered more in renal transplant patients,” according to the investigators.
Dr Breda’s team noted that de novo nephrolithiasis in the kidney graft can be detrimental when it affects structure and function. Graft placement on iliac vessels, immunosuppressive treatments, and comorbidities can all complicate treatment.
The investigators found a 1% prevalence of de novo nephrolithiasis in kidney grafts. The mean stone size on diagnosis was 11 mm. Mean stone size was larger in PCNL (25 mm) and open surgery (17 mm). The recurrence rate was 11% within a median 16 months. Drainage of the renal cavities on diagnosis was required for 41%.
As in the general population, the most frequent stone compositions were oxalate monohydrate (44%), followed by calcium-phosphate (19%), uric acid (17%), and struvite (11%). Less than half of patients had a metabolic disorder, most commonly hyperparathyroidism (25%), followed by hyperuricemia (16%), and to a lesser extent recurrent urinary tract infection (UTI)/stenosis/stasis (2%).
Only 6.0% of patients had a history of kidney stones in their native kidneys prior to transplantation, the investigators pointed out. New stones in the denervated kidney graft caused symptoms in three-quarters of patients, such as gross hematuria (10%), acute renal failure (17%), UTI (9%), or pain (3%).
According to Dr Breda’s team, these study findings support a minimum of annual imaging of the renal graft.
Boissier R, Rodriguez-Faba O, Zakri RH, et al. Evaluation of the effectiveness of interventions on nephrolithiasis in transplanted kidney. Eur Urol Focus. Published online December 23, 2022. doi:10.1016/j.euf.2022.11.019