Outcomes of left renal vein stenting in patients with nutcracker syndrome

Background: Nutcracker syndrome (NCS) is a rare condition that can be manifested with hematuria, flank pain, pelvic varicosities, or chronic pelvic congestion related to left renal vein (LRV) compression. Open surgery, specifically LRV transposition, has been the mainstay of treatment, but in the past few years, LRV stenting has emerged as a less invasive alternative without sufficient evidence to support it. This study aimed to assess outcomes of renal vein stenting in the treatment of NCS. Methods: A retrospective chart review of patients with NCS who underwent LRV stenting between 2010 and 2018 was performed. End points were perioperative adverse outcomes, symptom relief, and stent patency. Symptom resolution was classified as complete, partial, and none on the basis of the interpretation of medical records on clinical follow-up. Standard descriptive statistics and survival analysis were used. Results: Eighteen patients (17 female; mean age, 38.1 ± 16.9 years) diagnosed with NCS and treated with LRV stenting were identified. Five of these had a prior LRV transposition that had failed within a mean of 7.0 ± 4.9 months, manifested by symptom recurrence (or no improvement) along with imaging evidence of persistently severe renal vein stenosis. Twelve patients had coexisting pelvic congestion syndrome treated with gonadal vein embolization. The most frequent sign and symptom were hematuria (10/18 patients) and flank pain (15/18 patients), respectively. All patients received self-expanding stents (mean diameter, 12.8 ± 1.6 mm), the smaller ones typically placed in the previously transposed LRVs. No perioperative complications occurred. Nine patients were discharged on the same day; the remaining patients stayed longer for pain control (mean hospital stay, 1.0 ± 1.3 days). At an average follow-up of 41.4 ± 26.6 months, 13 (72.2%) patients had symptoms resolved or improved (9 complete, 4 partial). Three of the five patients whose symptoms remained unchanged had previous LRV transposition surgery, and two of these three patients eventually required renal autotransplantation. Six of 10 patients who presented with hematuria had it resolved. Three patients underwent a stent reintervention at 5.8 months, 16.8 months, and 51.7 months because of symptom recurrence or stent restenosis. The two early ones required balloon venoplasty and the third one restenting. Two-year primary and primary assisted patency was 85.2% and 100%, respectively. No stent migration occurred. Conclusions: Endovascular treatment with renal vein stenting is safe, providing encouraging results with good midterm patency rates and symptom relief. Minimally invasive approaches may have a potential role in the treatment of NCS. Larger series and longer follow-up are needed to better assess the comparative performance against LRV transposition.