Quest for the Vulnerable Atheroma: Carotid Stenosis and Diametric Strain--A Feasibility Study

Ophthalmic artery reversal predicts contralateral body weakness symptoms better than carotid Doppler velocity-preliminary results

Background

The measurement of blood velocity in the carotid artery has been the most popular noninvasive method of identifying and classifying carotid stenosis for half a century. Carotid stenosis is an indicator of elevated risk of stroke; anatomic revascularization reduces the chance of stroke by more than half. Controversy persists on how patients with severe carotid stenosis should be selected for anatomic revascularization. Patients with a connected circle of Willis (coW) might not benefit from anatomic revascularization; patients with two segments missing in the coW are most likely to benefit from revascularization.

Methods

Based on this analysis of data from carotid duplex examinations and transcranial Doppler examinations including ophthalmic artery (OA) direction in 28 patients, a refined carotid examination protocol is proposed. This refinement includes Doppler measurement of OA flow direction and documentation of internal carotid artery (ICA) bruit in addition to the adoption of an ICA peak systolic velocity (PSV) criterion exceeding 350 cm/s for identification of the patient most likely to benefit from carotid stenosis treatment.

Results

Sensitivity and specificity of OA direction or carotid bruit are 84.6%±5.4%, 71.4%±2.1% and for PSV >350 cm/s are 84.6%±5.4%, 59.5%±2.3% for predicting contralateral body weakness.

Conclusions

The proposed examination can be performed with the same duplex scanner and scan head currently used for carotid examinations with little additional time.

Hypothesis of "stroke-stop" formula: a tool for risk index determination in development of acute cerebrovascular disease in asymptomatic individuals with carotid stenosis

Background

Extracranial carotid artery disease is considered a risk factor for developing acute cerebrovascular diseases. The paper suggests the “Stroke-Stop” formula as hypothesis for the determination of the risk of developing stroke in asymptomatic individuals with carotid stenosis. The formula is based on a mathematical calculation of the major risk factors for stroke: the degree of ICA (internal carotid artery) stenosis, the morphological structure of the atherosclerotic plaque and the level of lipoprotein-associated phospholipase A2 (Lp-PLA2) concentration.

Methods

The cross sectional study included 70 patients with atherosclerotic ICA stenosis. Among vascular inflammatory markers, Lp-PLA2 was determined with concentration 252.7–328.6 mg/l. The obtained results were evaluated using descriptive statistics (the frequency, percentage ratio) as well as the one-way analysis of variance (ANOVA) and chi-square test.

Results

The risk of stroke development is eminently increasing with the progression of ICA stenosis and elevation of Lp-PLA2 levels. In patients with echolucent plaque, the risk of stroke development was significantly higher in correlation with patients with echogenic plaque. Based on calculations using “Stroke-Stop” formula, three main groups were generated: low (< 70 points), medium (70–100 points) and high (> 100 points) risk of stroke development.

Conclusions

Hypothesis of “Stroke-Stop” formula is proposed for better selection of patients who should be indicated for surgical treatment and will be evaluated in prospective study. In order to verify this hypothesis, we plan to do prospective study using “Stroke-Stop” formula for ipsilateral annual stroke rate in asymptomatic individuals with carotid stenosis who receive conservative therapy.

Stenosis, ulceration of the atherosclerotic plaque and Lp-PLA2 concentration are calculated

3 groups of stroke risk development were set (low, medium and high)

Proposed formula form personalized approach to the diagnosis and prevention of stroke

Dynamic carotid plaque imaging using ultrasonography

OBJECTIVE

Dynamic image analysis of carotid plaques has demonstrated that during systole and early diastole, all plaque components will move in the same direction (concordant motion) in some plaques. However, in others, different parts of the plaque will move in different directions (discordant motion). The aim of our study was (1) to determine the prevalence of discordant motion in symptomatic and asymptomatic plaques, (2) to develop a measurement of the severity of discordant motion, and (3) to determine the correlation between the severity of discordant motion and symptom prevalence.

METHODS

A total of 200 patients with 204 plaques resulting in 50% to 99% stenosis (112 asymptomatic and 92 symptomatic plaques) had video recordings available of the plaque motion during 10 cardiac cycles. Video tracking was performed using Farneback's method, which relies on frame comparisons. In our study, these were performed at 0.1-second intervals. The maximum angular spread (MAS) of the motion vectors at 10-pixel intervals in the plaque area was measured in degrees. Plaques were classified as concordant (MAS, <70°), moderately discordant (MAS, 70°-120°), and discordant (MAS, >120°).

RESULTS

Motion was discordant in 89.1% of the symptomatic plaques but only in 17.9% of asymptomatic plaques (P < .001). The prevalence of symptoms increased with increasing MAS. For a MAS >120°, the hazard ratio for the presence of symptoms was 47.7 (95% confidence interval, 18.1-125.6) compared with the rest of the plaques after adjustment for the degree of stenosis and mean pixel motion. The area under the receiver operating characteristic curve for the prediction of the presence of symptoms using the MAS was 0.876 (95% confidence interval, 0.823-0.929). The use of the median MAS (120°) as a cutoff point classified 86% of the plaques correctly (sensitivity, 81.4%; specificity, 91.2%; positive predictive value, 90.2%; and negative predictive value, 83.0%).

CONCLUSIONS

The use of the MAS value to identify asymptomatic plaques at increased risk of developing symptoms and, in particular, stroke should be tested in prospective studies.