[Ultrasonografic monitoring of hemodynamic parameters in symptomatic and asymptomatic patients with high-grade carotid stenosis prior and following carotid endarterectomy].
ABSTRACT Doppler ultrasonography is now a reliable diagnostic tool for noninvasive examination of the morphology and hemodynamic parameters of extracranial segments of blood vessels that participate in the brain vascularisation. This diagnostic modality in recent years become the only diagnostic tool prior to surgery. The aim of the study was to determine hemodynamic status in symptomatic and asymtomatic patients with severe carotid stenosis prior to and after carotid endarterectomy (CEA).
A total of 124 symptomatic and 94 asymptomatic patients who had underwent CEA at the Clinic for Cardiovasculare Disease "Dedinje" in Belgrade were included in this study. Doppler ultrasonography examinations were performed one day before CEA and seven days after it. The peak systolic velocity (PSV), end-dyastolic velocity (EDV), time-averaged maximum blood flow velocity (MV), resistance index (RI) and the blood flow volume (BFV) of the ipsilateral and the contralateral internal carotid artery (ICA) were measured.
Diabetes was the only risk factor found significantly more frequent in symptomatic patients. There were significantly more occluded contralateral ICAs in the group of symptomatic patients. There was a significant increase in PSV, EDV, MV and BFV of the ipsilateral ICA after CEA and a significant decrease in PSV, EDV, MV and BFV of the contralateral ICA after CEA. RI is the only hemodynamic parameter without significant changes after CEA in both groups of patients. Comparing the values of hemodynamic parameters after CEA between the group of symptomatic and the group of asymptomatic patients no significant differences were found.
The occlusion of the contralateral ICA is an important factor differentiating between symptomatic and asymptomatic patients with severe carotid stenosis. Successful surgery provides good recovery of cerebral hemodynamics in both symtomatic and asymptomatic patients.
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ABSTRACT: To investigate the association between diameter and flow velocity of the carotid arteries and ischemic stroke. Peak systolic velocity, end diastolic velocity, Pourcelot resistance index, blood flow volume, luminal diameter, and carotid plaque burden were measured and compared in 240 ischemic stroke (IS) patients without history of stroke, 163 chronic stable IS patients, and 236 nonstroke controls (age, >or=40 years). Data were also compared between stroke subtypes (large artery atherosclerosis, lacunar, cardioembolic, or undetermined origin). Acute as well as chronic stable IS patients had significantly lower flow velocities and flow volume, higher resistance index than nonstroke controls in the common carotid artery (CCA), internal carotid artery and external carotid artery, and larger common carotid artery diameter. The differences were found across all IS subtypes and in stroke patients with as well as without carotid plaque. Comparisons between these subgroups showed significant differences in end diastolic velocity, resistance index, flow velocity, and diameter that were more prominent in the CCA. After adjusting for carotid plaque and cardiovascular risk factors, the associations between the above-mentioned parameter and stroke remained significant. Stroke patients in acute as well as chronic stable phase appeared to have larger CCA diameters, lower carotid flow velocities and volume, and higher resistance index than nonstroke patients independently of extracranial carotid atherosclerosis. These findings need to be confirmed by a prospective study.Journal of Clinical Ultrasound 01/2007; 35(6):322-30. · 0.80 Impact Factor
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ABSTRACT: We wanted to characterize the immediate effect of endarterectomy on flow of the arteries composing the extracranial carotid artery system. Transit time ultrasound probes were used to measure flow through the carotid bifurcation in 48 patients undergoing endarterectomy. Maximum single-diameter stenosis affecting the internal carotid artery (ICA) was determined by angiography. The significance of differences between means were determined by t tests and analysis of variance; linear and nonparametric correlation analyses were also applied to analyze the relation between stenosis and several flow-derived parameters. Common carotid artery flow significantly increased (p = 0.0043) from a mean value of 264 +/- 99 ml/min to 314 +/- 98 ml/min, corresponding to an average percent increase of 34.3% +/- 71.3%. ICA flow increased from 128 +/- 69 ml/min to 173 +/- 66 ml/min (p < 0.0001), with an average percent increase of 74.9% +/- 114.9%. External carotid artery (ECA) flow decreased from 129 +/- 61 ml/min to 106 +/- 49 ml/min (p = 0.0098), representing an average percent decrease of -5.2% +/- 48.2%. The difference between ECA and ICA mean flow changes is highly significant (p < 0.001). The percent change in ECA flow did not correlate with preoperative stenosis. We noted, however, a positive correlation between stenosis and the ECA/ICA flow ratio before endarterectomy (Spearman r = 0.31, p = 0.032), indicating that more severe stenosis led to a greater distribution of blood into the ECA. The ECA/ICA flow ratio fell from an initial value (ECFbef/ICFbef) of 1.52 +/- 1.74 before endarterectomy to 0.69 +/- 0.37 (ECFaft/ICFaft) after endarterectomy (p = 0.0006). The data are consistent, with the ECA being an important collateral path for cerebral perfusion when ICA stenosis exists. When endarterectomy relieves bifurcation stenosis, common carotid artery blood flow is redistributed preferentially to the ICA at the expense of ECA flow, consistent with a change in the relative resistances of the two vessels resulting from operative reconstruction.Journal of Vascular Surgery 10/1995; 22(4):349-58; discussion 358-60. · 2.98 Impact Factor
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ABSTRACT: Antithrombotic therapy for intracranial arterial stenosis was recently evaluated in the Warfarin versus Aspirin for Symptomatic Intracranial Disease (WASID) trial. A prespecified aim of WASID was to identify patients at highest risk for stroke in the territory of the stenotic artery who would be the target group for a subsequent trial comparing intracranial stenting with medical therapy. WASID was a randomized, double-blinded, multicenter trial involving 569 patients with transient ischemic attack or ischemic stroke due to 50% to 99% stenosis of a major intracranial artery. Median time from qualifying event to randomization was 17 days, and mean follow-up was 1.8 years. Multivariable Cox proportional hazards models were used to identify factors associated with subsequent ischemic stroke in the territory of the stenotic artery. Subsequent ischemic stroke occurred in 106 patients (19.0%); 77 (73%) of these strokes were in the territory of the stenotic artery. Risk of stroke in the territory of the stenotic artery was highest with severe stenosis > or =70% (hazard ratio 2.03; 95% confidence interval 1.29 to 3.22; P=0.0025) and in patients enrolled early (< or =17 days) after the qualifying event (hazard ratio 1.69; 95% confidence interval 1.06 to 2.72; P=0.028). Women were also at increased risk, although this was of borderline significance (hazard ratio 1.59; 95% confidence interval 1.00 to 2.55; P=0.051). Location of stenosis, type of qualifying event, and prior use of antithrombotic medications were not associated with increased risk. Among patients with symptomatic intracranial stenosis, the risk of subsequent stroke in the territory of the stenotic artery is greatest with stenosis > or =70%, after recent symptoms, and in women.Circulation 01/2006; 113(4):555-63. · 14.95 Impact Factor