title: Stent migration after endovascular stenting in patients with nutcracker syndrome.
abstract: OBJECTIVE
  In this study, we sought to investigate the incidence of stent migration after endovascular stenting (EVS) in patients with nutcracker syndrome (NCS) and to discuss the related factors.
  
  
  METHODS
  We retrospectively evaluated the data of all patients with NCS who were treated by EVS at our single center between January 2004 and October 2014. Data collection included details on clinical findings, radiologic evaluation, laboratory values, EVS procedure, stent size, and morbidity of stent migration. Sex, size of stents, interval (between EVS and stent migration), and preoperative parameters of the left renal vein (LRV) on duplex ultrasound (anteroposterior diameter in aortomesenteric portion and renal hilum of LRV, peak velocity in aortomesenteric portion and renal hilum of LRV) were analyzed.
  
  
  RESULTS
  A total of 75 patients (49 men) with a median age of 27 years (range, 16-43 years) underwent EVS for NCS. During a mean 55 months (range, 6-126 months) of follow-up, stent migration occurred in five patients (6.7%), and all of them were male. The stent migrated into the right ventricle in one patient, right atrium in one patient, inferior vena cava in two patients, and left side of the LRV in one patient. There were no significant differences in preoperative anteroposterior diameter and peak velocity of the aortomesenteric portion and renal hilum of the LRV on duplex ultrasound between patients with and without stent migration. There were also no significant differences in these parameters between patients with deployment of 12-mm and 14-mm-diameter stents.
  
  
  CONCLUSIONS
  Stent migration after EVS in patients with NCS is not as rare as we originally thought. Preoperative anatomic parameters of the LRV need to be more accurately measured. Stent choice for the individual patient and accurate stent deployment are important to avoid stent migration. Closer follow-up and early detection and treatment can reduce the number of stent migrations into the heart.
authors.affiliation: Department of Vascular Surgery, The First Affiliated Hospital, School of Medicine, Zhejiang University, Hangzhou, China.
authors.forename: Ziheng
authors.initials: Z
authors.lastname: Wu
authors.affiliation: Department of Vascular Surgery, The First Affiliated Hospital of Wenzhou Medical University, Wenzhou, China.
authors.forename: Xiangtao
authors.initials: X
authors.lastname: Zheng
authors.affiliation: Department of Vascular Surgery, The First Affiliated Hospital, School of Medicine, Zhejiang University, Hangzhou, China.
authors.forename: Yangyan
authors.initials: Y
authors.lastname: He
authors.affiliation: Department of Vascular Surgery, Hangzhou First People's Hospital, Hangzhou, China.
authors.forename: Xin
authors.initials: X
authors.lastname: Fang
authors.affiliation: Department of Vascular Surgery, The First Affiliated Hospital, School of Medicine, Zhejiang University, Hangzhou, China.
authors.forename: Donglin
authors.initials: D
authors.lastname: Li
authors.affiliation: Department of Vascular Surgery, The First Affiliated Hospital, School of Medicine, Zhejiang University, Hangzhou, China.
authors.forename: Lu
authors.initials: L
authors.lastname: Tian
authors.affiliation: Department of Vascular Surgery, The First Affiliated Hospital, School of Medicine, Zhejiang University, Hangzhou, China. Electronic address: doczhk@163.com.
authors.forename: Hongkun
authors.initials: H
authors.lastname: Zhang
mesh_terms: D000293:Adolescent; D000328:Adult; D057510:Endovascular Procedures / Q000009:adverse effects; D005260:Female; D005500:Follow-Up Studies; D005548:Foreign-Body Migration; D006801:Humans; D008297:Male; D059228:Renal Nutcracker Syndrome / Q000628:therapy*; D012082:Renal Veins; D012189:Retrospective Studies; D015607:Stents / Q000009:adverse effects*; D013577:Syndrome; D016896:Treatment Outcome; D055815:Young Adult