title: Low prevalence of collateral cerebral circulation in the circle of Willis in patients with severe carotid artery stenosis and recent ischemic stroke.
abstract: BACKGROUND
  The circle of Willis is thought to play a key role in development of collateral flow in patients with internal carotid artery stenosis (ICAS).
  
  
  OBJECTIVE
  To assess flow in the circle of Willis in patients with recent ischemic stroke (IS).
  
  
  METHODS
  The study included 371 patients, 102 symptomatic with severe ICAS and recent IS (within the last 3 months) (group I) and 269 asymptomatic with severe ICAS (group II). Flow in the middle (MCA), anterior (ACA) and posterior (PCA) cerebral arteries and pattern of the cross-flow through anterior (ACoA) and posterior (PCoA) communicating arteries were assessed with transcranial color-coded Doppler ultrasonography (TCCD).
  
  
  RESULTS
  The ACoA or PCoA was less prevalent in group I than in group II (54% vs. 78%, p < 0.001 and 20% vs. 42%, p < 0.001, respectively), resulting in lower peak-systolic velocity (PSV) in the MCA in group I vs. group II (p = 0.015). Any collateral pathway was present in 67% of patients in group I, compared to 86% in group II (p < 0.001). Both PSV and end-diastolic (EDV) flow velocity in the ACA were lower in patients with recent IS, compared to asymptomatic subjects (71 ±24 cm/s vs. 86 ±34 cm/s, p < 0.001 and 32 ±12 cm/s vs. 37 ±17 cm/s, p = 0.038, respectively). Presence of ACoA or PCoA and higher PSV in the MCA and ACA were associated with significant risk reduction of IS (RR = 0.28 (95% CI = 0.16-0.49, p < 0.001), RR = 0.28 (95% CI = 0.15-0.52, p < 0.001), RR = 0.97 (95% CI = 0.96-0.99, p < 0.001), RR = 0.99 (95% CI = 0.98-0.99, p < 0.032), respectively). However, ROC curves failed to show reliable MCA or ACA PSV cut-offs for IS risk assessment.
  
  
  CONCLUSIONS
  The ACoA and PCoA seem to play a key role in the evaluation of IS risk in subjects with severe ICAS.
authors.affiliation: Department of Interventional Cardiology, Institute of Cardiology, Jagiellonian University School of Medicine, John Paul II Hospital, Krakow, Poland.
authors.forename: Rafał
authors.initials: R
authors.lastname: Badacz
authors.affiliation: Department of Interventional Cardiology, Institute of Cardiology, Jagiellonian University School of Medicine, John Paul II Hospital, Krakow, Poland ; Department of Cardiac and Vascular Diseases, Institute of Cardiology, Jagiellonian University School of Medicine, John Paul II Hospital, Krakow, Poland.
authors.forename: Tadeusz
authors.initials: T
authors.lastname: Przewłocki
authors.affiliation: Department of Interventional Cardiology, Institute of Cardiology, Jagiellonian University School of Medicine, John Paul II Hospital, Krakow, Poland.
authors.forename: Izabela
authors.initials: I
authors.lastname: Karch
authors.affiliation: Department of Interventional Cardiology, Institute of Cardiology, Jagiellonian University School of Medicine, John Paul II Hospital, Krakow, Poland ; Department of Cardiac and Vascular Diseases, Institute of Cardiology, Jagiellonian University School of Medicine, John Paul II Hospital, Krakow, Poland.
authors.forename: Piotr
authors.initials: P
authors.lastname: Pieniążek
authors.affiliation: Department of Interventional Cardiology, Institute of Cardiology, Jagiellonian University School of Medicine, John Paul II Hospital, Krakow, Poland.
authors.forename: Agnieszka
authors.initials: A
authors.lastname: Rosławiecka
authors.affiliation: Department of Interventional Cardiology, Institute of Cardiology, Jagiellonian University School of Medicine, John Paul II Hospital, Krakow, Poland.
authors.forename: Szymon
authors.initials: S
authors.lastname: Mleczko
authors.affiliation: Department of Vascular and Endovascular Surgery, John Paul II Hospital, Krakow, Poland.
authors.forename: Andrzej
authors.initials: A
authors.lastname: Brzychczy
authors.affiliation: Department of Vascular and Endovascular Surgery, John Paul II Hospital, Krakow, Poland.
authors.forename: Mariusz
authors.initials: M
authors.lastname: Trystuła
authors.affiliation: Department of Interventional Cardiology, Institute of Cardiology, Jagiellonian University School of Medicine, John Paul II Hospital, Krakow, Poland.
authors.forename: Krzysztof
authors.initials: K
authors.lastname: Żmudka
authors.affiliation: Department of Interventional Cardiology, Institute of Cardiology, Jagiellonian University School of Medicine, John Paul II Hospital, Krakow, Poland.
authors.forename: Anna
authors.initials: A
authors.lastname: Kabłak-Ziembicka
keywords: carotid artery stenosis; circle of Willis; collateral circulation; stroke; transcranial Doppler