Pathophysiology of unilateral high-grade carotid artery stenosis: evaluation of intracranial haemodynamics by analysis of velocity waveforms from the middle cerebral artery

1992 ◽  
Vol 83 (3) ◽  
pp. 357-366 ◽  
Author(s):  
Heinrich Fürst ◽  
Wolfgang H. Hartl ◽  
Ingrid Jansen ◽  
Barbara Fink ◽  
Axel Piepgras ◽  
...  

1. Transcranial flow velocity waves were measured via Doppler sonography of the middle cerebral artery during hypo-, hyper- and normo-capnia. Applying the principle of vascular impedance, flow velocity waves were analysed in 30 young subjects, 37 elderly subjects and 18 patients with high-grade unilateral internal carotid artery disease. 2. There was evidence that the relative peak-to-peak velocity in the middle cerebral artery could serve as an index of peripheral wave reflection and cerebral resistance (CRi). The response of CRi to changes in arterial CO2 concentration (CRi reactivity) showed a clear age-dependency. However, the absolute side-to-side asymmetry of CRi reactivity (ΔR) did not vary with age and could be used to define a normal range (0–4%CRi/vol.%CO2). 3. Selective angiography demonstrated no cerebral cross-flow through the anterior part of the circle of Willis in nine patients with carotid artery stenosis whose absolute ΔR was above the normal range and whose CRi reactivity of the affected hemisphere was lower than that of the healthy opposite hemisphere. Conversely, another group of nine patients, whose ipsilateral CRi reactivity was higher than the contralateral CRi reactivity, demonstrated cross-flow through the anterior part of the circle of Willis. 4. ΔR may be used to identify patients who have high-grade internal carotid artery stenosis and present with low cerebral vascular resistance owing to poor intracerebral collaterals.

2020 ◽  
Vol 10 (1) ◽  
Author(s):  
Olivier Bill ◽  
Dimitris Lambrou ◽  
Guillermo Toledo Sotomayor ◽  
Ivo Meyer ◽  
Patrik Michel ◽  
...  

Abstract Cervical and transcranial Doppler (TCD) are widely used as non-invasive methods in the evaluation of acute ischemic stroke (AIS) patients. High-grade carotid artery stenosis induces haemodynamic changes such as collateral flow and a so-called post-stenotic flow pattern of the middle cerebral artery (MCA), which appears flattened, with a reduction of the velocity difference between systole and diastole. We studied the influence of carotid artery stenosis and other variables on the flow pattern in the MCA using the pulsatility index (PI), a quantitative TCD parameter reflecting the flow spectrum in a large of cohort AIS patients. We performed ultrasound examinations of 1825 AIS patients at the CHUV from October 2004 to December 2014. We extracted patient characteristics from the ASTRAL registry. Carotid stenosis severity was classified as < 50%, 50–70%, 70–90% and > 90%, or occlusion, according to Doppler velocity criteria. We first determined variables associated with stenosis grade. Then we performed a multivariate analysis after adjusting for baseline differences, using MCA PI as dependent variable. Carotid stenosis > 70% (− 0.07) and carotid stenosis > 90%, or occlusion (− 0.14) and left side (− 0.02) are associated with lower MCA PI values. Age (+0.006 PI units per decade), diabetes (+0.07), acute ischemic changes on initial CT (+0.03) and severe plaque morphology (+0.18) are associated with higher MCA PI values. We found a number of clinical and radiological conditions that significantly influence the PI of the MCA, including high-grade ipsilateral carotid stenosis in AIS patients. We provide for the first time a quantitative evaluation of the effect of these influencing factors from a large cohort of AIS patients.


2014 ◽  
Vol 120 (1) ◽  
pp. 126-131 ◽  
Author(s):  
Eric J. Heyer ◽  
Joanna L. Mergeche ◽  
E. Sander Connolly

Object Transcranial Doppler (TCD) is frequently used to evaluate peripheral cerebral resistance and cerebral blood flow (CBF) in the middle cerebral artery prior to and during carotid endarterectomy (CEA). Patients with symptomatic carotid artery stenosis may have reduced peripheral cerebral resistance to compensate for inadequate CBF. The authors aim to determine whether symptomatic patients with reduced peripheral cerebral resistance prior to CEA demonstrate increased CBF and cognitive improvement as early as 1 day after CEA. Methods Fifty-three patients with symptomatic CEA were included in this observational study. All patients underwent neuropsychometric evaluation 24 hours or less preoperatively and 1 day postoperatively. The MCA was evaluated using TCD for CBF mean velocity (MV) and pulsatility index (PI). Pulsatility index ≤ 0.80 was used as a cutoff for reduced peripheral cerebral resistance. Results Significantly more patients with baseline PI ≤ 0.80 exhibited cognitive improvement 1 day after CEA than those with PI > 0.80 (35.0% vs 6.1%, p = 0.007). Patients with cognitive improvement had a significantly greater increase in CBF MV than patients without cognitive improvement (13.4 ± 17.1 cm/sec vs 4.3 ± 9.9 cm/sec, p = 0.03). In multivariate regression model, a baseline PI ≤ 0.80 was significantly associated with increased odds of cognitive improvement (OR 7.32 [1.40–59.49], p = 0.02). Conclusions Symptomatic CEA patients with reduced peripheral cerebral resistance, measured as PI ≤ 0.80, are likely to have increased CBF and improved cognitive performance as early as 1 day after CEA for symptomatic carotid artery stenosis. Revascularization in this cohort may afford benefits beyond prevention of future stroke. Clinical trial registration no: NCT00597883 (ClinicalTrials.gov).


Stroke ◽  
2001 ◽  
Vol 32 (9) ◽  
pp. 2075-2080 ◽  
Author(s):  
Christopher M. McPherson ◽  
Daniel Woo ◽  
Paul L. Cohen ◽  
Arthur M. Pancioli ◽  
Brett M. Kissela ◽  
...  

2020 ◽  
pp. 1-7
Author(s):  
Ching-I Wu ◽  
Chia-Lun Wu ◽  
Feng-Chieh Su ◽  
Shun-Wen Lin ◽  
Wen-Yi Huang

<b><i>Background:</i></b> The coincidence of coronary artery disease (CAD) and carotid artery stenosis (CAS) was observed. However, the association between pre-existing CAD and ischemic stroke (IS) outcome in patients with high-grade CAS remains unclear. We aimed to investigate the association between pre-existing CAD and outcomes of acute IS patients with high-grade CAS. <b><i>Methods:</i></b> From January 1, 2007, to April 30, 2012, we enrolled 372 acute IS patients with high-grade CAS and prospectively observed them for 5 years. Demographic features, vascular risk factors, comorbidities, and outcomes were compared between patients with and without pre-existing CAD. <b><i>Results:</i></b> Among 372 individuals, 75 (20.2%) patients had pre-existing CAD and 297 (79.8%) patients did not have pre-existing CAD. The prevalence rates of hypertension, congestive heart failure, chronic kidney disease, and gout in patients with pre-existing CAD were significantly higher than in those without pre-existing CAD (<i>p</i> = 0.017, <i>p</i> &#x3c; 0.001, <i>p</i> = 0.002, and <i>p</i> &#x3c; 0.001, respectively). The multivariate Cox proportional hazards model revealed that pre-existing CAD was a significant risk factor for a 5-year all-cause mortality in acute IS patients with high-grade CAS (hazard ratio = 2.26; 95% confidence interval = 1.35–3.79; <i>p</i> = 0.002). <b><i>Conclusion:</i></b> Pre-existing CAD was associated with an increased risk of 5-year mortality in acute IS patients with high-grade CAS. Intensive treatment for the pre-existing CAD may reduce long-term mortality in acute IS patients with high-grade CAS.


2010 ◽  
Vol 138 (7-8) ◽  
pp. 494-497
Author(s):  
Dragoslav Nenezic ◽  
Slobodan Tanaskovic ◽  
Predrag Gajin ◽  
Nenad Ilijevski ◽  
Goran Vucurevic

Introduction. Multislice CT angiography (CTA) is a noninvasive and quick technique to image carotid artery stenosis, as well as intracerebral vasculature. Modern multidetector CTA produces images with a high resolution of, not only the contrast-filled lumen, but also of the vessel wall and the surrounding soft tissues. Multiple studies have verified the ability of CTA to provide an accurate representation of the degree of carotid stenosis in comparison to digital subtraction angiography, both for moderate and high-grade stenosis. Because of its fast and accurate vessel imaging, CT angiography is increasingly used in the assessment of carotid artery stenosis. Case Outline. A 37-year-old female patient was admitted at the Vascular Surgery Clinic of the Institute for Cardiovascular Diseases 'Dedinje', Belgrade, for angiography and endovascular procedure of a high-grade stenosis of the left common carotid artery based on Multislice CT findings brought by the patient. She complained of problems which we considered to be the result of cerebral circulation ischemia. After detailed diagnostic procedures, we concluded that no pathological lesions could be verified either on the left common carotid artery or other supraaortic branches. Therefore, the patient was discharged for further neurological examinations. Conclusion. Although Multislice CTA has many advantages over classical angiography, its validity should be taken with reserve, especially in younger patients.


Radiology ◽  
2004 ◽  
Vol 230 (1) ◽  
pp. 70-76 ◽  
Author(s):  
Schila Sabeti ◽  
Martin Schillinger ◽  
Wolfgang Mlekusch ◽  
Tassilo Nachtmann ◽  
Wilfried Lang ◽  
...  

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