RU2631559C1 - Method for selection of operative intervention in case of internal carotid arteries damage - Google Patents

Abstract

FIELD: medicine.

SUBSTANCE: prior to operation, ultrasound examination of atherosclerotic plaques is performed. The examination is carried out by a linear transducer in a cross section with emission frequency of 11 MHz in B mode. The intensity of acoustic ultrasound signal reflected from the zones of interest - heterogeneous components located under the cover of an atherosclerotic plaque - is recorded. In the presence of intensity of acoustic ultrasonic signals from non-uniform components of carotid plaques of 20 dB or less, operative intervention in the form of carotid endarterectomy is performed. In the presence of intensity of 28 dB or more - in the form of angioplasty with stenting.

EFFECT: high reliability and accuracy of surgical intervention to prevent postoperative embolic brain damage.

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Description

The invention relates to medicine, in particular to neurology, and can be used in the choice of surgical intervention, in particular, carotid endarterectomy (CEE) or angioplasty with stenting (CAS) for lesions of the internal carotid arteries (ICA) in patients with acute embolic foci of ischemia in substance of the brain.

Angioreconstructive operations on the carotid arteries are associated with a risk of ischemic damage to brain matter (both symptomatic and asymptomatic).

The study of postoperative asymptomatic ischemic changes in the brain detected during MRI is the subject of a number of studies. In particular, Ajay Gupta et al. in their systematic review showed that the presence of asymptomatic brain damage according to MRI in patients without a history of history of stroke was associated with a twofold increase in the likelihood of progression of existing cognitive dysfunction and the development of stroke in the future [Ajay G., Ashley E., Gino G et al. Silent Brain Infarction and Risk of Future Stroke. A systematic Review and Meta-Analysis. Stroke. 2016; 47: 719-725]. In addition, the epidemiological data obtained by various authors also indicate that the presence of asymptomatic brain damage can contribute to the development of cognitive dysfunction, dementia, increased overall mortality and the main potential complication - stroke [Bokura N., Kobayashi S., Yamaguchi S. et al. Silent brain infarction and subcortical white matter lesions increase the risk of stroke and mortality: a prospective cohort study. J Stroke Cerebrovasc Dis. 2006; 15: 57-63].

Studying the mechanisms of formation of acute foci of ischemia is a complex task. The small size of the foci of ischemia, their localization and chronic ischemic preconditioning of the brain are factors that can explain why some cerebrovascular events are not clinically manifested [Fanning J.P., Wesley A.J., Wong A.A., Fraser J.F. Emerging spectra of silent brain infarction. Stroke. 2014; 45: 3461-3471]. Understanding the extent to which different angio-imaging techniques can predict the development of damage to brain matter is extremely important.

In a number of studies, the incidence of clinically asymptomatic embolic lesions of the brain substance after the stenting procedure (using a protective device) was cited, which was reduced to the fact that after CEE there were less acute foci of ischemia than after stenting.

Schaudigel et al. in their meta-analysis showed that among 2117 patients (1363 patients of the CAS group and 754 of the CEE group) the level of acute foci of ischemia (OOI) (according to the DV-MRI) was significantly higher in patients of the CAS group [Schnaudigel S., Groschel K., Pilgram SM, Kastrup A. New brain lesion after carotid stenting versus carotid endarterectomy: a systematic review of the literature. Stroke. 2008; 39: 1911-1919]. In another meta-analysis, which includes data from 20 studies that performed a comparative assessment of brain damage based on DV-MRI, it was shown that the frequency of embolic damage to the brain in CAS was higher than that in CEE [Gargiulo G., Sannino A., Stabile E. et al. . New cerebral lesion at magnetic resonance imaging after carotid artery stenting versus endarterectomy: an update meta-analysis. PloS One. 2015; 10 (5)].

Thus, the methodology for choosing the surgical intervention for lesions of the internal carotid arteries is important in terms of preventing postoperative embolic damage to the brain.

To date, there is a known method of choosing surgical intervention for lesions of the internal carotid arteries by examining a patient using the CREST protocol, including anamnestic symptomatic studies and the degree of stenosis of the carotid arteries, in the presence of transient ischemic attacks, transient blindness or minor stroke prior to the study of the carotid artery during 180 days before randomization, as well as in the presence of stenosis of 50% or more when performing angiography, or 70% or more when performing CT angiography or magnetic re onansnoy angiography, or 70% by ultrasound, which occurred during the preceding six months or who caused the need for anticoagulation therapy, and to recommend CAS was contraindication for EEF [Brott T.G., Howard R.W., Howard G. et al. Stenting versus endarterectomy for treatment of carotid-artery stenosis. N Engl J Med., 2010; 363: 11-23.]. However, this method does not have high accuracy when choosing the surgical tactics of surgical intervention for CAS or CEE in patients with damage to the internal carotid arteries.

There is also a method of selecting surgery for lesions of the internal carotid arteries using randomized clinical trials of NASCET and ECST. The severity of morphological changes was assessed using transcranial dopplerography, duplex scanning of the arteries of the neck, spiral CT angiography / MR angiography, and cerebral angiography. And the choice of surgical intervention was carried out according to the degree of ICA stenosis. Moreover, a contraindication to the CEE in "symptomatic" patients was stenosis <30% without aspirin + chronic occlusion of the ICA, and in "asymptomatic" patients - stenosis <60%; chronic occlusion of the ICA; stratification of the carotid artery; stenosis> 60% with a risk of complications> 6%. Contraindications to carotid angioplasty with stenting were asymptomatic patients older than 80 years; difficulty accessing the artery; severe neurological deficit; severe cerebral atrophy / lacunar infarction; dementia Of the local risk factors for stenting, it should be noted: pronounced concentric calcification of the plaque; total occlusion of the ICA and severe deformity of the distal segment of the carotid artery (DV Svistov Surgical treatment of atherosclerotic lesions of the arteries of the carotid pool (diagnosis, indications, contraindications, perspective). St. Petersburg, International Neurological Journal, 2005. - V. 1, No. 1 . - S. 59). The disadvantages of the method are the complexity of its use when choosing a surgical intervention for lesions of the internal carotid arteries.

The technical result consists in the simplicity of the study and the expansion of the arsenal of technical means of choosing surgical intervention in patients with damage to the internal carotid arteries with high reliability and accuracy.

The technical result is achieved by the fact that the choice of surgical intervention for lesions of the internal carotid arteries is carried out by ultrasound examination of atherosclerotic plaques on the cross section before the operation with a linear sensor with a radiation frequency of 11 MHz in B-mode, followed by recording the degree of intensity of the acoustic ultrasonic signal reflected from the zones of interest - heterogeneous components located directly under the cover of the atherosclerotic plaque, and in the presence of acoustic intensity ultrasonic signals from the heterogeneous components of the carotid artery plaques of 20 dB or less perform surgery in the form of a carotid endarterectomy, and in the presence of an intensity of 28 dB or more - in the form of angioplasty with stenting.

The method is as follows.

In the preoperative period, ultrasound is performed (for which the Philips iE 33 device was used). Ultrasound examination of atherosclerotic plaques is carried out on a cross section before surgery with a linear sensor with a radiation frequency of 11 MHz in B-mode. Then register the degree of intensity of the acoustic ultrasonic signal reflected from areas of interest, namely, heterogeneous components located directly under the tire of the studied atherosclerotic plaque. The heterogeneity of the ASB components located under its cover is estimated using computer image analysis and recording the values of the intensity of the acoustic characteristics of the signal in the zones of interest using the ROI (Region of interest) program. Moreover, in the presence of the intensity of acoustic ultrasonic signals from the heterogeneous components of the carotid artery plaques located directly under the ASB cover, 20 dB or less, surgery is performed in the form of a carotid endarterectomy, and in the presence of an intensity of 28 dB or more - in the form of angioplasty with stenting.

All patients included in the study were divided into 2 groups depending on the type of surgical intervention. The first group consisted of 42 patients who underwent CEE from the ICA, the second group consisted of 36 patients who underwent CAS (using a filter-type protective device).

Based on the anamnesis and the results of a neurological examination, it was found that in both studied groups (with CEE and CAS), patients with the asymptomatic course of the disease were most often encountered (86% and 75%, respectively).

The main characteristics of the examined patients depending on the type of surgical intervention are presented in table 1.

The vast majority of patients in the CEE and CAS groups (95% and 94%, respectively) were diagnosed with arterial hypertension, and every second patient had two or more risk factors for the development of vascular disease (see table 1).

In the preoperative period, all patients underwent ultrasound examination (for which the Philips iE 33 device with a linear sensor with a radiation frequency of 11 MHz was used). The degree of heterogeneity of the ASB was estimated using computer analysis of the image and recording the values of the intensity of the acoustic characteristics of the signal in the zones of interest (heterogeneous components located directly under the cover of the atherosclerotic plaque) using the ROI program (Region of interest).

In all cases, a neurological examination was carried out 24 hours after an open surgical or endovascular intervention, taking into account the assessment of the deficit on the NIH stroke scale (J. Biller et. Al., 1990, T. Brott et. Al., 1989).

The state of the brain substance before and 24 hours after surgical and endovascular treatment was evaluated by the results of DV-MRI (Magnetom Verio, Siemens, 3 Tesla). Due to the predominance of foci of small sizes, the assessment of damage to the brain substance was carried out on diffusion-weighted images with a diffusion weighting coefficient of b = 1000.

For the intensity of the ultrasonic signal, the difference in the average values (in different groups) was evaluated (by checking the proximity of the distributions to normal) by Student's criterion, and the threshold values were determined by ROC analysis. The balance of the compared groups (by the intensity of the ultrasonic signal) of the groups according to characteristics significantly prognostically unfavorable (according to the literature) for the formation of acute foci of ischemia was checked by univariate analysis. The results were considered statistically significant at p≤0.05. For calculations, the statistical package SAS 9.3 (SAS Institute, Inc, Cary, NC) was used.

Research results

In all patients, the procedures for angioreconstruction were successful; no clinical signs of the development of acute NMC in the postoperative period were observed. However, in a neuroimaging DV-MRI study 24 hours after surgery, the appearance of acute foci of ischemia (OOI) was observed in 25 (32%) patients in the absence of negative neurological dynamics. An analysis of brain DV-MRI data showed that after CEE foci of ischemia on the intervention side were found in 9 (21%) patients, with OOI in both cerebral hemispheres immediately in only one case. In patients with CAS, foci of ischemia were detected in 16 (43%) cases, in 7 cases they were located bilaterally. Thus, during ICA operations, the development of OOI in the substance of the brain (including cases of localization of foci in both hemispheres) was statistically significantly more often (p = 0.05) in patients after CAS compared with CEE.

A comparison of the history and results of a neurological examination of patients of two groups with identified changes in DV-MRI are presented in table 2.

Analysis of changes in brain matter after interventions showed that in most (78%) clinically symptomatic patients after stenting there is an increased tendency to form OOI. Differences in the number of foci of ischemia in clinically asymptomatic and symptomatic patients undergoing CEE surgery were not observed (see table 2).

In patients of the CEE group, new foci of ischemic damage to the substance of the brain were observed in 9 (21%) cases, and all of them had an ultrasonic signal intensity (in the preoperative study) of 28 dB or higher. In patients without postoperative damage to the substance of the brain 33 (79%), a shift in the intensity of the ultrasonic signal (in the preoperative study) was observed towards lower values (less than 28 dB). This difference in the intensity of the ultrasonic signal was also statistically significant (p = 0.05).

According to our data, in patients with a CAS group with postoperative verified new foci of ischemia in the brain substance, the ultrasound signal during preoperative examination was low-intensity and ranged from 20 dB or lower, in the absence of postoperative foci of ischemia, the ultrasound signal during preoperative examination was statistically significant (p = 0.01 ) other, high-intensity, and reached more than 20 dB (see table 3).

The occurrence of postoperative foci of ischemia was associated with the intensity of the ultrasound signal (measured during preoperative examination), and the nature of this relationship in the CEE and CAS groups was different: in the CEE group, postoperative foci of ischemia were associated with high-intensity ultrasound signals, and in the CAS group, on the contrary, with low-intensity (see Fig. 1). In FIG. Figure 1 shows the intensity of the ultrasound signal reflected from a carotid plaque (during preoperative ultrasound examination) in patients with postoperatively identified foci of ischemia (•) and without them (o) in groups undergoing carotid angioplasty with stenting (CAS) and carotid endarterectomy (CEE) . It can be seen in the drawing that plaques with predominantly low-intensity preoperative ultrasound signals (less than 20 dB) were embologous with CAS, and high-intensity (more than 28 dB) with CEE.

Low- and high-intensity ultrasonic signals separated by cut-off points (classification thresholds) differed (median) statistically significantly (p = 0.05): 10.1 versus 36.9 (for the CEE group) and 16.1 versus 26.4 (for the CAS group).

The cut-off point of low- and high-intensity ultrasonic signals (associated with the presence or absence of postoperative foci of ischemia) for the CEE group was visually determined (since the subgroups of low- and high-intensity signals in this group do not intersect) and is equal to 28 dB, the cut-off point for the CAS group was determined using ROC analysis (see Fig. 2) (since the low- and high-intensity signals in this group partially overlap) and is equal to 20 dB (AUC = 87%, p = 0.05). In FIG. Figure 2 shows the characteristic (ROC) information curve of the preoperative ultrasound method for predicting embolic brain damage in carotid angioplasty with stenting: the sensitivity of the method is 75%, specificity is 100% (at the cut-off point of low and high-intensity ultrasonic signals equal to 20 dB).

Therefore, for the case of CEE, the sensitivity and specificity of the preoperative ultrasound method for predicting postoperative embolic brain injuries are equal and make up 100% (at the cut-off point of low and high-intensity signals equal to 28 dB), and for the case of CAS, the sensitivity of the method is 75%, and the specificity is 100 % (at a cut-off point of 20 dB).

Examples of the method

Example 1

Patient S., 58 years old.

Clinical diagnosis: Dyscirculatory encephalopathy, decompensation stage. Arterial hypertension 3 tbsp., 2 tbsp. Atherosclerosis. Stenosis of the right internal carotid artery 75-80%. Chronic smoker's bronchitis. Chronic gastritis, remission.

Complaints at admission to the Research Center of Neurology Federal State Budgetary Institution for a decrease in memory and concentration during the last two weeks. From the anamnesis of the disease it is known that for a long time suffers from arterial hypertension with an increase in blood pressure to 170/100 mm Hg. I did not take antihypertensive drugs regularly, I did not control blood pressure.

In the neurological status at admission, the intention was determined when performing coordinating tests, staggering in the Romberg position.

When conducting a duplex scan of the main arteries of the head, atherosclerotic stenosis of the right internal carotid artery of 75-80% was revealed due to the heterogeneous structure with a predominance of the hypoechogenic component of the atherosclerotic plaque.

When conducting ultrasound with the subsequent determination of the degree of intensity of the ultrasonic signal reflected from the areas located under the cover of the atherosclerotic plaque, a value of 5.57 dB is obtained (see Fig. 3).

According to the MRI of the brain before surgery, there are changes in both hemispheres of the cerebrum of vascular origin.

The presence of atherosclerotic stenosis of the right internal carotid artery is 75-80%, with the aim of primary prevention of the development of cerebrovascular accident, a decision was made to conduct carotid endarterectomy from the right internal carotid artery.

The appearance of acute focal neurological symptoms after the intervention is not fixed.

When conducting DV-MRI of the brain 24 hours after the intervention of foci of increased intensity of the MR signal in the substance of the brain was not detected.

Example 2

Patient P., 74 years old.

Clinical diagnosis: Atherosclerosis. Stenosis of the left internal carotid artery 80-85%. Arterial hypertension 1 tbsp. Chronic smoker's bronchitis.

Upon admission to the Scientific Center of Neurology Federal State Budgetary Scientific Institution, the patient complained about the instability of blood pressure figures with a maximum increase of up to 190/100 mm Hg. Duplex scanning revealed stenosis of the left internal carotid artery of 80-85%. The patient was consulted by an angiosurgeon; surgical treatment is recommended.

In the neurological status upon receipt of focal neurological symptoms was not determined.

When conducting duplex scanning of the main arteries of the head, atherosclerotic stenosis of the left internal carotid artery of 80-85% was confirmed due to the heterogeneous structure with a predominance of the hyperechoic component of the atherosclerotic plaque.

When conducting an ultrasound examination with subsequent determination of the degree of intensity of the ultrasonic signal reflected from the areas located under the atherosclerotic plaque, a value of 32.39 dB is obtained (see Fig. 4).

According to the MRI of the brain before surgery, vascular lesions were detected in both hemispheres of the large brain.

The presence of atherosclerotic stenosis of the left internal carotid artery 80-85%, with the aim of primary prevention of the development of cerebrovascular accident, it was decided to conduct carotid angioplasty with stenting of the left internal carotid artery.

The appearance of acute focal neurological symptoms after the intervention is not fixed.

When performing DV-MRI of the brain 24 hours after the intervention, changes in the substance of the brain were not detected.

Thus, the claimed method has high reliability and accuracy of the choice of surgical intervention for lesions of the internal carotid arteries and in addition it is easy to use and available in almost any medical institution.

Claims (1)

A method for selecting surgical intervention for lesions of the internal carotid arteries by ultrasound examination of atherosclerotic plaques, characterized in that their ultrasound examination is carried out in cross section before surgery with a linear sensor with a radiation frequency of 11 MHz in B-mode, followed by recording the intensity of the acoustic ultrasonic signal reflected from the zones interest - heterogeneous components located under the cover of an atherosclerotic plaque, and in the presence of intensity of acoustic Ultrasound signals from heterogeneous components of carotid artery plaques of 20 dB or less are performed as a carotid endarterectomy, and in the presence of an intensity of 28 dB or more, they are performed in the form of angioplasty with stenting.

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