title: Impact of practice patterns in shunt use during carotid endarterectomy with contralateral carotid occlusion.
abstract: OBJECTIVE
  This study investigated the association between surgeon practice pattern in shunt placement and 30-day stroke/death in patients undergoing carotid endarterectomy (CEA) with contralateral carotid occlusion (CCO).
  
  
  METHODS
  Among 6379 CEAs performed in the Vascular Study Group of New England (VSGNE) between 2002 and 2009, we identified 353 patients who underwent CEA with CCO and compared the 30-day stroke/death rate with 5279 patients who underwent primary, isolated CEA with a patent contralateral carotid artery. Within patients with CCO, we examined the 30-day stroke/death rate across the reason for shunt placement and two distinct surgeon practice patterns in shunt placement: surgeons who selectively used a shunt (≤95% of CEAs) or routinely used a shunt (>95% of CEAs). We used observed/expected (O/E) ratios to provide risk-adjusted comparisons across groups.
  
  
  RESULTS
  Of 353 patients with CCO, 118 (33%) underwent CEA without a shunt, 173 (49%) underwent CEA using a shunt placed routinely, and 62 (18%) had a shunt placed for a neurologic indication. Rates of 30-day stroke/death across categories of reason for shunt use were no shunt, 3.4%; routine shunt, 4.0%; and shunt for indication, 4.8% (P = .891). The risk of 30-day stroke/death was higher for surgeons who selectively placed shunts (5.6%) in all their CEAs and lower for surgeons who routinely placed shunts (1.5%, P = .05). The risk of 30-day stroke/death was >1 in patients undergoing selective shunting (O/E ratio, 1.4; 95% confidence interval [CI], 1.1-1.7) and <1 for surgeons who placed shunts routinely (O/E ratio, 0.4; 95% CI, 0.2-0.9). Stroke/death rates were lowest when individual surgeons' intraoperative decisions reflected their usual pattern of practice: 1.5% stroke/death rate when "routine" surgeons placed a shunt, 3.4% when "selective" surgeons did not place a shunt, and 7.6% stroke/death rate for "selective" surgeons who placed a shunt (P = .05 for trend).
  
  
  CONCLUSIONS
  The risk of 30-day stroke/death is higher in CEA in patients with CCO than with a patent contralateral carotid artery. Surgeons who place shunts selectively during CEA have higher rates of stroke/death in patients with CCO. This suggests that shunt use for CCO during CEA is associated with fewer complications, but only if the surgeon uses a shunt as part of his or her routine practice in CEA. Surgeons should preoperatively consider their own practice pattern in shunt use when faced with a patient who may require shunt placement.
authors: Section of Vascular Surgery, Dartmouth-Hitchcock Medical Center, Lebanon, NH; Dartmouth-Hitchcock Medical Center, The Dartmouth Institute for Health Policy and Clinical Practice, Hanover, NH, USA. philip.goodney@hitchcock.org
authors: Philip P
authors: PP
authors: Goodney
authors: Jessica B
authors: JB
authors: Wallaert
authors: Salvatore T
authors: ST
authors: Scali
authors: David H
authors: DH
authors: Stone
authors: Virendra
authors: V
authors: Patel
authors: Palma
authors: P
authors: Shaw
authors: Brian W
authors: BW
authors: Nolan
authors: Jack L
authors: JL
authors: Cronenwett
mesh_terms: D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D016893:Carotid Stenosis / Q000175:diagnosis / Q000401:mortality / Q000503:physiopathology / Q000601:surgery*; D002560:Cerebrovascular Circulation; D016894:Endarterectomy, Carotid / Q000009:adverse effects / Q000401:mortality; D005260:Female; D017052:Hospital Mortality; D006801:Humans; D008297:Male; D008875:Middle Aged; D009511:New England; D018579:Patient Selection; D010818:Practice Patterns, Physicians' / Q000706:statistics & numerical data; D011446:Prospective Studies; D012039:Regional Blood Flow; D012042:Registries; D018570:Risk Assessment; D012307:Risk Factors; D012720:Severity of Illness Index; D020521:Stroke / Q000209:etiology; D013997:Time Factors; D016896:Treatment Outcome