title: Effect of contralateral occlusion on long-term efficacy of endarterectomy in the asymptomatic carotid atherosclerosis study (ACAS). ACAS Investigators.
abstract: OBJECTIVE
  The Asymptomatic Carotid Atherosclerosis Study (ACAS) established the effectiveness of prophylactic carotid endarterectomy, for patients in good health who had stenosis >/=60%, if conducted by surgeons with a surgical morbidity and mortality of <3%. This secondary analysis was performed to determine whether the presence of contralateral cervical carotid occlusion alters the efficacy of asymptomatic ipsilateral carotid endarterectomy.
  
  
  METHODS
  One hundred sixty-three participants who had a baseline contralateral occlusion documented by Doppler ultrasound (77 medical, 86 surgical) were compared with 1485 participants with a patent contralateral carotid artery (748 medical, 737 surgical) for the risk of a combined end point of perioperative (30-day) death or stroke or long-term (5-year) ipsilateral stroke.
  
  
  RESULTS
  For those without contralateral occlusion, surgery was associated with a 6.7% absolute reduction in the 5-year risk (95% CI, 2.1% to 11.4%), while for those with a contralateral occlusion, surgery was associated with a 2.0% absolute increase in risk (95% CI, -9.3% to 5.2%), which was a statistically significant difference in the effect of surgery (P:=0.047). This difference is primarily attributable to low long-term risk for medically managed patients with contralateral occlusion.
  
  
  CONCLUSIONS
  While this post hoc analysis should be interpreted with caution, the findings suggest that endarterectomy in asymptomatic subjects with contralateral occlusion provides no long-term benefit (and may be harmful) in preventing stroke and death. These findings were a result of the benign course of medically treated subjects.
authors.affiliation: Department of Surgery, Division of Peripheral Vascular Surgery, Loyola University Medical Center, Stritch School of Medicine, Maywood, Ill, USA.
authors.forename: W H
authors.initials: WH
authors.lastname: Baker
authors.forename: V J
authors.initials: VJ
authors.lastname: Howard
authors.forename: G
authors.initials: G
authors.lastname: Howard
authors.forename: J F
authors.initials: JF
authors.lastname: Toole
mesh_terms: D000368:Aged; D001161:Arteriosclerosis / Q000150:complications*; D001241:Aspirin / Q000627:therapeutic use; D016893:Carotid Stenosis / Q000150:complications* / Q000000981:diagnostic imaging / Q000601:surgery*; D018572:Disease-Free Survival; D016894:Endarterectomy, Carotid; D005260:Female; D006801:Humans; D008297:Male; D011237:Predictive Value of Tests; D018570:Risk Assessment; D020521:Stroke / Q000209:etiology* / Q000401:mortality / Q000517:prevention & control; D015996:Survival Rate; D013995:Time; D016896:Treatment Outcome; D014463:Ultrasonography
chemical_list: D001241:Aspirin