title: Treatment of nutcracker syndrome with open and endovascular interventions.
abstract: OBJECTIVE
  Nutcracker syndrome (NS) is a rare cause of hematuria, flank pain, and renal venous hypertension due to compression of the left renal vein (LRV) between the aorta and the superior mesenteric artery. To evaluate outcomes of open surgery and endovascular interventions, we reviewed our experience.
  
  
  METHODS
  A retrospective review of clinical data of all patients treated at our institution with an intervention for NS between January 1, 1994, and February 28, 2014, was performed. Primary outcomes were morbidity and mortality. Secondary outcomes included late complications, patency, freedom from reintervention, and resolution of symptoms.
  
  
  RESULTS
  Thirty-seven patients (30 female, seven male) with a mean age of 27 years (range, 14-62 years) were treated. The most frequent symptom was flank pain (97%); the most frequent sign was hematuria (68%). NS was diagnosed with duplex ultrasound scanning with measurement of LRV diameters and flow velocities (87%), with computed tomography or magnetic resonance venography (94%), and with contrast venography with measurement of pressure gradients (93%). Initial treatment was open surgery in 36 patients, endovascular in 1. Distal transposition of the LRV into the inferior vena cava (IVC) was performed in 31 patients. Adjunctive procedures to optimize venous outflow included great saphenous vein cuff in six patients, great saphenous vein patch in four, and both cuff and patch in four. Three patients had patch alone; two had transposition of the left gonadal vein into the IVC. Two patients had anterior reimplantation of retroaortic LRV into the IVC. There were no major early complications, renal failure, or mortality. Three patients underwent early reinterventions within 30 days (stent, two; open revision, one). All LRVs and left gonadal veins were patent at discharge. Follow-up was 36.8 ± 52.6 months (range, 1-216 months). Reinterventions after 30 days were performed in eight patients because of LRV stenosis (n = 7) or LRV occlusion (n = 1). One stent migrated into the IVC and required endovascular removal with repeated stenting. Six patients required stenting. Primary, primary assisted, and secondary patencies at 24 months were 74%, 97%, and 100%, respectively. Freedom from reintervention at 12 and 24 months was 76% and 68%, respectively. Resolution of symptoms occurred in 33 patients (87%).
  
  
  CONCLUSIONS
  Open surgery, mostly LRV transposition, remains a safe and effective treatment of patients with NS. However, one of three patients after open repair required reintervention, most frequently LRV stenting. Open reconstruction should be tailored to the patient's anatomy, and placement of vein cuff or patch may reduce restenosis. Although renal vein stents improved patency, the safety and durability of currently available stents need to be established.
authors.affiliation: Division of Vascular and Endovascular Surgery, Mayo Clinic, Rochester, Minn.
authors.forename: Young
authors.initials: Y
authors.lastname: Erben
authors.affiliation: Division of Vascular and Endovascular Surgery, Mayo Clinic, Rochester, Minn. Electronic address: gloviczki.peter@mayo.edu.
authors.forename: Peter
authors.initials: P
authors.lastname: Gloviczki
authors.affiliation: Division of Vascular and Endovascular Surgery, Mayo Clinic, Rochester, Minn.
authors.forename: Manju
authors.initials: M
authors.lastname: Kalra
authors.affiliation: Division of Vascular and Interventional Radiology, Mayo Clinic, Rochester, Minn.
authors.forename: Haraldur
authors.initials: H
authors.lastname: Bjarnason
authors.affiliation: Division of Vascular and Endovascular Surgery, Mayo Clinic, Rochester, Minn.
authors.forename: Nanette R
authors.initials: NR
authors.lastname: Reed
authors.affiliation: Division of Vascular and Endovascular Surgery, Mayo Clinic, Rochester, Minn.
authors.forename: Audra A
authors.initials: AA
authors.lastname: Duncan
authors.affiliation: Division of Vascular and Endovascular Surgery, Mayo Clinic, Rochester, Minn.
authors.forename: Gustavo S
authors.initials: GS
authors.lastname: Oderich
authors.affiliation: Division of Vascular and Endovascular Surgery, Mayo Clinic, Rochester, Minn.
authors.forename: Thomas C
authors.initials: TC
authors.lastname: Bower
mesh_terms: D000293:Adolescent; D000328:Adult; D057510:Endovascular Procedures; D005260:Female; D006801:Humans; D008297:Male; D017538:Mesenteric Artery, Superior; D008875:Middle Aged; D010690:Phlebography; D059228:Renal Nutcracker Syndrome / Q000628:therapy*; D012082:Renal Veins; D012189:Retrospective Studies; D055815:Young Adult