title: Prevalence of venous anatomic variants and occlusion among patients undergoing implantation of transvenous leads.
abstract: BACKGROUND
  The implantation of transvenous leads may be prohibited by venous occlusion or anatomical variants. The prevalence of these conditions among patients undergoing transvenous pacing or implantable cardioverter defibrillator (ICD) leads implantation has not been systematically studied. This study examined the prevalence of venous anatomic variants and/or venous occlusion, and related risk factors, prior to lead implantation.
  
  
  METHODS
  The study included 273 consecutive patients scheduled for implantation of transvenous pacing or ICD leads. Before the procedure, the venous network of arms, neck, and thorax was evaluated by bilateral intravenous digital subtraction angiography (DSA).
  
  
  RESULTS
  Complete venous occlusion associated with developed collateral circulation was observed in 12 patients (4.4%); at the site of the left innominate vein in 9, left subclavian vein in 2, and right subclavian vein in 1 patient. Of 12 patients with venous occlusion, 7 patients had a history of prior surgical procedure. A persistent left superior vena cava was observed in 1 patient (0.4%). The presence of abnormal findings on DSA was significantly higher on the left than the right side (P < 0.001). The cardio-thoracic ratio (CTR) was significantly greater in patients with venous occlusions than patients with normal circulation (P = 0.012).
  
  
  CONCLUSIONS
  Asymptomatic venous abnormalities are not rare among patients requiring transvenous pacing lead implantation. Careful attention should be paid when implanting pacing or ICD leads from the left side, especially in patients with an increased CTR or history of prior insertion for central venous catheter.
authors.affiliation: Second Department of Internal Medicine, University of Occupational and Environmental Health, Yahatan-ishi, Kitakyushu, Japan.
authors.forename: Yasushi
authors.initials: Y
authors.lastname: Oginosawa
authors.forename: Haruhiko
authors.initials: H
authors.lastname: Abe
authors.forename: Yasuhide
authors.initials: Y
authors.lastname: Nakashima
mesh_terms: D000368:Aged; D015901:Angiography, Digital Subtraction; D001145:Arrhythmias, Cardiac; D016121:Brachiocephalic Veins / Q000033:anatomy & histology; D003097:Collateral Circulation; D017147:Defibrillators, Implantable; D005260:Female; D007839:Functional Laterality; D006801:Humans; D008297:Male; D015995:Prevalence; D012307:Risk Factors; D013350:Subclavian Vein / Q000033:anatomy & histology; D014680:Veins / Q000033:anatomy & histology*; D014689:Venous Insufficiency / Q000209:etiology