title: Extrinsic compression of the left innominate vein in hemodialysis patients.
abstract: OBJECTIVE
  Central venous stenosis is a common problem in hemodialysis patients. The most well known cause is intrinsic stenosis, usually a result of subclavian vein catheterization. A lesser-known cause is extrinsic compression of the left innominate vein. This study investigates the prevalence of this phenomenon in a series of patients undergoing diagnostic fistulography.
  
  
  METHODS
  One hundred six fistulograms of 48 patients were reviewed retrospectively. In reviewing the fistulograms, attention was paid to the central veins, which were graded for extrinsic compression of the left innominate vein. Presence of collaterals was noted, as well as the presence of any intrinsic stenosis of the left innominate or subclavian veins. Medical records were reviewed for a history of catheterization of the left-side venous system for hemodialysis or any other reason. The type of vascular access (native fistula, synthetic graft) and indication for the fistulogram were recorded.
  
  
  RESULTS
  Some degree of extrinsic compression was observed in 21 of 48 of patients (44%). Twelve of 48 patients (25%) had mild, six of 48 patients (13%) had moderate and three of 48 patients had (6%) severe compression. Among patients with any degree of extrinsic compression only four of 21 patients (19%) had previous left subclavian or jugular catheterization. Intrinsic stenosis was observed in 11 of 48 patients (23%). All but two of them had undergone previous left subclavian or jugular catheterization and two had concomitant extrinsic compression. Collaterals were seen in 21 of 48 patients (44%). Eleven of 21 patients (52%) with extrinsic compression showed collateral veins. Ten of 11 patients (91%) with intrinsic stenosis had collateral veins. All three patients with severe extrinsic compression were symptomatic and were treated with stent placement after angioplasty failed because of elastic recoil.
  
  
  CONCLUSIONS
  Extrinsic compression is a common finding on diagnostic hemodialysis fistulography and may be hemodynamically significant. Unlike intrinsic stenosis, it is unrelated to previous central catheterization. Angioplasty alone may not be adequate for treatment and stent placement may be required.
authors.affiliation: Department of Radiology, University of Pennsylvania Medical Center, Philadelphia, Pennsylvania 19104, USA.
authors.forename: Maxim
authors.initials: M
authors.lastname: Itkin
authors.forename: Michael J
authors.initials: MJ
authors.lastname: Kraus
authors.forename: Scott O
authors.initials: SO
authors.lastname: Trerotola
mesh_terms: D001166:Arteriovenous Shunt, Surgical; D016121:Brachiocephalic Veins / Q000000981:diagnostic imaging; D002405:Catheterization, Central Venous / Q000009:adverse effects*; D003251:Constriction, Pathologic / Q000209:etiology / Q000628:therapy; D005260:Female; D006801:Humans; D008297:Male; D011859:Radiography; D006435:Renal Dialysis; D012189:Retrospective Studies; D034941:Upper Extremity / Q000098:blood supply*