1. Olivier Bill 1,2, Guillermo Toledo Sotomayor 1, Ivo Meyer 2, Patrik Michel 2, Tiago Moreira 3 Julien Niederhauser 1, Lorenz Hirt 2. 1 Stroke Unit, GHOL, Site de Nyon, Nyon, Switzerland 2 Neurology Service, Stroke Center, CHUV, Lausanne Switzerland 3 Department of Neurology, Karolinska Stroke Research Unit, Karolinska University Hospital- Solna, Stockholm, Sweden Olivier Bill 1,2, Guillermo Toledo Sotomayor 1, Ivo Meyer 2, Patrik Michel 2, Tiago Moreira 3 Julien Niederhauser 1, Lorenz Hirt 2. 1 Stroke Unit, GHOL, Site de Nyon, Nyon, Switzerland 2 Neurology Service, Stroke Center, CHUV, Lausanne Switzerland 3 Department of Neurology, Karolinska Stroke Research Unit, Karolinska University Hospital- Solna, Stockholm, Sweden Stroke Unit Precerebral stenoses influence pulsatility index values in acute ischemic strokes 2. Methods We conducted a retrospective analysis of ultrasound examinations on 2159 AIS at the CHUV (Lausanne University Hospital) from October 14, 2004, to December 31, 2014. We extracted degrees of stenosis and PI values on the main pre- and intracerebral arteries, and clinical characteristics from the ASTRAL registry. All patients had an exam within 7 days of onset. We excluded pre-existing intracranial stenosis and bilateral carotid stenosis. Carotid stenosis severity was divided into 90% according to established Doppler criteria. The variance of stenosis grade and MCA PI were analyzed first. Linear regression analyses were then performed adjusting for baseline differences using MCA PI as dependent variable. We retained as as significance level at p<0.05. 2. Methods We conducted a retrospective analysis of ultrasound examinations on 2159 AIS at the CHUV (Lausanne University Hospital) from October 14, 2004, to December 31, 2014. We extracted degrees of stenosis and PI values on the main pre- and intracerebral arteries, and clinical characteristics from the ASTRAL registry. All patients had an exam within 7 days of onset. We excluded pre-existing intracranial stenosis and bilateral carotid stenosis. Carotid stenosis severity was divided into 90% according to established Doppler criteria. The variance of stenosis grade and MCA PI were analyzed first. Linear regression analyses were then performed adjusting for baseline differences using MCA PI as dependent variable. We retained as as significance level at p<0.05. 4. Conclusions PI of the MCA is significantly reduced in patients with severe ipsilateral carotid stenosis, and increased in aged, hypertensive and alcohol- consuming patients, advising careful assessment of the PI in these stroke patients. Further studies are required to understand the clinical implications of these findings on intracranial hypertension, cerebral autoregulation and vessel recanalization. 4. Conclusions PI of the MCA is significantly reduced in patients with severe ipsilateral carotid stenosis, and increased in aged, hypertensive and alcohol- consuming patients, advising careful assessment of the PI in these stroke patients. Further studies are required to understand the clinical implications of these findings on intracranial hypertension, cerebral autoregulation and vessel recanalization. Table 2: Histograms of PI distribution against Gaussian curve Table 3: Multivariate Analysis 3. Results Mean MCA PI was 0.87 in the 112 AIS with ≥90% stenosis, and 1.06 in 2047 AIS <90% ICA stenosis (p<0.0001)*. (Table 1 & Table 2) In the multivariate analysis, age (Beta 0.36), pre-existing hypertension (Beta 0.07), and chronic alcohol consumption (Beta 0.05) increase and carotid stenosis significantly decreases (Beta -0.09) MCA PI (r 2 : 0.15) (Table 3 & Table 4). 3. Results Mean MCA PI was 0.87 in the 112 AIS with ≥90% stenosis, and 1.06 in 2047 AIS <90% ICA stenosis (p<0.0001)*. (Table 1 & Table 2) In the multivariate analysis, age (Beta 0.36), pre-existing hypertension (Beta 0.07), and chronic alcohol consumption (Beta 0.05) increase and carotid stenosis significantly decreases (Beta -0.09) MCA PI (r 2 : 0.15) (Table 3 & Table 4). 50-70% Acute STroke Registry & Analysis of Lausanne 5. References 1) Demchuck et al, Thrombolysis in Brain Ischemia (TIBI) Transcranial Doppler Flow Grades Predict Clinical Severity, Early Recovery, and Mortality in Patients Treated With Intravenous Tissue Plasminogen Activator, Stroke.2001; 32: 89-93 2) Tsivgoulis et al, Real-Time Validation of Thrombolysis in Brain Ischemia (TIBI) Flow Grading of Recanalization during Intra-Arterial Rescue for Acute Ischemic Stroke, Stroke 2008; 39:591. 3) Alexandrov et al, Ultrasound Enhancement of Fibrinolysis, Stroke.2009; 40: S107-S110 4) Baumgartner et al, Assessment of ≥50% and <50% Intracranial Stenoses by Transcranial Color-Coded Duplex Sonography, Stroke.1999; 30: 87-92 5) Burgin et al, Transcranial Doppler Ultrasound Criteria for Recanalization After Thrombolysis for Middle Cerebral Artery Stroke, Stroke.2000; 31: 1128-1132 5. References 1) Demchuck et al, Thrombolysis in Brain Ischemia (TIBI) Transcranial Doppler Flow Grades Predict Clinical Severity, Early Recovery, and Mortality in Patients Treated With Intravenous Tissue Plasminogen Activator, Stroke.2001; 32: 89-93 2) Tsivgoulis et al, Real-Time Validation of Thrombolysis in Brain Ischemia (TIBI) Flow Grading of Recanalization during Intra-Arterial Rescue for Acute Ischemic Stroke, Stroke 2008; 39:591. 3) Alexandrov et al, Ultrasound Enhancement of Fibrinolysis, Stroke.2009; 40: S107-S110 4) Baumgartner et al, Assessment of ≥50% and <50% Intracranial Stenoses by Transcranial Color-Coded Duplex Sonography, Stroke.1999; 30: 87-92 5) Burgin et al, Transcranial Doppler Ultrasound Criteria for Recanalization After Thrombolysis for Middle Cerebral Artery Stroke, Stroke.2000; 31: 1128-1132 1.Objectives Transcranial doppler (TCD) is widely used in acute ischemic stroke (AIS) patients. Pulsatility index (PI) is a rheological TCD parameter used in clinical assessment of intracranial hypertension and vascular recanalization. We studied the influence of precerebral stenoses and other variables on middle cerebral artery (MCA) PI in anterior circulation AIS. 1.Objectives Transcranial doppler (TCD) is widely used in acute ischemic stroke (AIS) patients. Pulsatility index (PI) is a rheological TCD parameter used in clinical assessment of intracranial hypertension and vascular recanalization. We studied the influence of precerebral stenoses and other variables on middle cerebral artery (MCA) PI in anterior circulation AIS. ICA Stenosis degree Mean MCA PI SD 0-50%1.060.24 50-70%1.120.21 70-90%1.080.25 >90% or occlusion 0.87*0.29 SEPBeta Age0.000 0.359 Chronic hypertension0.0090.0020.065 Chronic alcohol consumption 0.0110.0220.045 High degree precerebral stenosis 0.0050.000-0.090 0-50%50-70% 70-90% >90% or occlusion Table 1: mean MCA PI values Table 4