Analysis of Functional Connectivity When using Complementary

Methods of Treatment in Patients with Asymptomatic Carotid

Stenosis

A. S. Lepekhina

, M. L. Pospelova

, G. E. Trufanov

, T. M. Alekseeva

, D. N. Iskhakov

T. A. Bukkieva

, D. S. Chegina

, N. N. Semibratov

, B. S. Litvincev

and Y. N. Tsarevskaya

MRI Department, Almazov National Medical Research Centre, Akkuratova Str., 2, Saint-Petersburg, Russia

Neurology Department, Almazov National Medical Research Centre, Akkuratova Str., 2, Saint-Petersburg, Russia

Clinical Depertment, Institution of Toxicology, FMBA of Russia, Bekhtereva Str., 1, Saint-Petersburg, Russia

Keywords: Asymptomatic Carotid Stenosis, Leeching, Leech Therapy, Functional MRI, Connectome.

Abstract: Investigation of the mechanisms of neuroplasticity and detection of changes in the connectome in patients

with asymptomatic carotid stenosis is relevant for the development of new preventive, therapeutic strategies

and prediction of disease outcomes. Leech therapy (hirudotherapy, leeching) is one of the most well-known

and studied methods of complementary medicine, with proven pathogenetic mechanisms, widely and

justifiably used in patients with vascular diseases. Patients received a leech therapy course (10 sessions). All

patients underwent resting state functional MRI, complaints and neurological status were evaluated before

and after the course of leeching. After a leech therapy course, patients with asymptomatic carotid stenosis

noted a significant improvement in their condition (reduction of headaches, dizziness, noise in the head and

ears, optical and vestibular disorders, visual impairment). The connectivity of the main structures of the brain

increased, which is an important morphofunctional indicator of improved brain function. The connectome

study provides new approaches to understand the integrative brain function in health and disease, and to assess

the effectiveness of the treatment.

ABBREVIATIONS

TIA – transient ischemic attack

ACAS – asymptomatic carotid stenosis

FC – functional connectivity

ICA – internal carotid artery

1 INTRODUCTION

Stenosis of the internal carotid artery without

transient ischemic attack (TIA) or acute

cerebrovascular accident is asymptomatic. Cognitive

impairment has been described in patients with

clinically asymptomatic stenosis (Wang, 2017; Lin,

2012; Lin, 2014; Cheng, 2012). The pathogenetic

mechanism of the occurrence of these disorders in

patients with asymptomatic carotid stenosis (ACAS)

has not been fully studied. Patients with

asymptomatic carotid stenosis are at an increased risk

of developing acute vascular episodes, so the

frequency of stroke and TIA in patients with stenosis

of more than 70% reaches 40% over the next 2 years

NASCET (Streffer, 1992).

The proven fact is that the disorders in functional

connectivity (FC) are the basis of the most common

cerebral pathology. Currently, in the development of

pathophysiological models of cerebral pathology, not

only the pathology of specific parts of the brain is

evaluated, but also the characteristics of disorders of

neural networks (Seung, 2014; Fornito, 2015). The

basis of compensation of impaired functions of the

nervous system are the mechanisms of neuroplasticity

- the ability of nervous tissue to structural and

functional restructuring after its damage. Several

mechanisms of the functional connectivity

reconstruction, which underlie neuroplasticity, are

described: changes in the proportion of the

connections, recombination, reconnection, and

regeneration.

The use of multimodal neuroimaging techniques

makes it possible to identify structural and functional

disorders in patients with ACAS (Fornito 2015,

Lepekhina, A., Pospelova, M., Trufanov, G., Alekseeva, T., Iskhakov, D., Bukkieva, T., Chegina, D., Semibratov, N., Litvincev, B. and Tsarevskaya, Y.

Analysis of Functional Connectivity When using Complementary Methods of Treatment in Patients with Asymptomatic Carotid Stenosis.

DOI: 10.5220/0008953603730378

In Proceedings of the 13th International Joint Conference on Biomedical Engineering Systems and Technologies (BIOSTEC 2020) - Volume 1: BIODEVICES, pages 373-378

ISBN: 978-989-758-398-8; ISSN: 2184-4305

373

Efimtsev A.Yu. et al. 2016). It is known that changes

in the connections between neurons occur within

three minutes after the onset of a stroke. Disruption

of the functional connectivity may be associated with

the loss of neurons or indirect effects in remote areas

of the brain. Therefore, structural and interregional

neuroimaging of the FC can demonstrate high clinical

potential for ischemic brain damage (Gulyaeva,

2016).

The study of the mechanisms of neuroplasticity in

patients with ACAS, the detection of changes of the

FC in cerebrovascular diseases and during treatment

is relevant for the development of new preventive and

therapeutic strategies, as well as predicting the

outcome (Bukkieva, 2015). As a result of the work, a

high potential for the restoration of the disturbed

connectome due to the activation of neuroplasticity

processes was noted (Kublanov 2018, Kublanov

2018, Petrenko, 2019).

There is a decrease in the severity or termination

of headaches, dizziness, noise in the head, flickering

flies before the eyes in more than 70% of cases in

patients with chronic cerebral ischemia and with

ACAS during leech therapy (Konyrtayeva, 2015;

Chernetsky 2003, Pospelova 2008

2 PURPOSE

Сonnectome study in patients with asymptomatic

carotid stenosis of more than 65% during leech

therapy course for develop therapeutic and preventive

strategies.

3 MATERIALS AND METHODS

3.1 Study Population

The study was conducted in accordance with the

principles of the Helsinki Declaration. Under our

supervision, there were 16 patients (10 women and 6

men, aged 61 to 81 years, average age 72.4 ± 3.4

years) with ACAS of one or both of the internal

carotid artery (ICA) 60-75%. 3 patients underwent

carotid enderectomy surgery from one internal

carotid artery, with persistent stenosis of more than

65% of the contralateral ICA. All patients suffered

from hypertension (disease duration from 3 to 20

years). 2 patients had diabetes (type II). The diagnosis

of ACAS was made on the basis of anamnesis,

complaints, and instrumental examination data.

All patients underwent ultrasound triplex

examination of the brachiocephalic arteries on a

Logiq Q7 Expert General Electric apparatus using B-

mode, color and energy Doppler mapping, and pulse-

wave Doppler. The study used a linear sensor with a

frequency of 8.5-10.0 mHZ, a standard protocol with

an assessment of the degree of stenosis of the lumen

of the common and internal carotid arteries by area

and diameter (European Carotid Surgery Trialists).

The study was approved by the ethics committee

of the Federal State Budgetary Institution «National

Medical Research Center V.A. Almazova» of the

Ministry of Health of Russia (extract from the

protocol No. 41 of 02/12/2018).

Criteria for exclusion of patients from the study

were: 1. The presence of a history of psycho-organic

pathology, epilepsy, brain tumors, injuries of the

brain and spinal cord. 2. The presence of severe

concomitant pathology (exacerbation of rheumatism,

acute infections, cirrhosis, alcoholism, drug

addiction, cardiomyopathy with thromboembolism in

the arteries of the brain, acute myocardial infarction,

heart failure 3-4 severity, blood diseases). 3. The

simultaneous administration of drugs that can distort

the results of treatment (anxiolytics, antidepressants,

barbiturates, lithium preparations, narcotic

analgesics, reserpine).

Patients complained of paroxysmal and / or

persistent headaches of one- or two-sided

localization, aching, pulsating; unsystematic and / or

systemic instant, short-term or prolonged dizziness;

noise in the head and / or in the ears; hearing loss; the

inability to look at moving objects; flashing flies

before the eyes.

In neurological status, the main symptoms were

manifested by lethargy of pupil reactions - in 6

patients, convergence failure - in 4 patients,

nystagmus with extreme leads - in 5, asymmetry of

tendon reflexes - in 7, vegetative instability - in 8,

tremor of fingers of extended arms - in 5, dynamic

elements in 6 patients and static-locomotor ataxia in

5 patients.

Patients underwent a leech therapy course

consisting of 10 sessions (2,5 months) according to

their own patent of the Russian Federation No.

2327494 (Pospelova M.L., 2008). Leech therapy was

carried out 1-2 times a week, once 2-6 leeches were

placed. The most common points of the prefix: the

occipital zone (along the edge of hair growth), the

cervical spine (paravertebral), mastoid processes,

lumbar, sacral spine (paravertebral), coccyx (in the

gluteal fold), the region of the liver, spleen, heart,

around the navel. Against the background of leech

NDNSNT 2020 - Special Session on Non-invasive Diagnosis and Neuro-stimulation in Neurorehabilitation Tasks

374

therapy, patients continued to take antihypertensive,

antiplatelet, and lipid-lowering drugs.

Complaints (scale: yes/no) of subjective

sensations and neurological status were evaluated

before the start of leech therapy and after the end of

the course of treatment (after 2-2.5 months).

Patients were instructed to lie with their eyes open

(do not sleep), without fixing the gaze. Thus, for

everyone there were identical conditions of a state of

rest, and this had a minimal effect on the visual and

auditory working networks of the brain.

3.2 MR Imaging Protocol

All patients underwent structural MRI with obtaining

T1 and T2 weighted images and FLAIR (Fluid

attenuated inversion) to exclude brain tumors, strokes

and other pronounced pathological changes. All

patients underwent functional resting state MRI at 2

time points - before and after the course of leech

therapy. Pulse sequence data of a T1-weighted

gradient echo (MP-RAGE – Magnetization Prepared

Rapid Acquired Gradient Echoes) was collected to

combine fMRI data with anatomical structures of the

brain, slice thickness – 4.5 mm, number of slices – 29,

the number of repetitions – 120, scan time – 6

minutes. The main feature of this sequence is its high

resolution and 0.8 mm isotropic voxel. BOLD (Blood

Oxygenation Level Dependent) were using with

repetition time (TR) = 3000 ms, echo time (TE) = 50

ms, field of view (FOV) = 230 mm and matrix size

128*128, slice thickness – 4.0 mm, the number of

repetitions – 120, scan time – 6 minutes.

3.3 Image Analyses

Analyzing the data of functional MRI, when

performing an intergroup statistical analysis (two-

sample t-test, comparing the resting state before

treatment and after a course of leech therapy) with the

choice of the medial prefrontal cortex (MPFC) as the

region of interest.

3.4 Statistical Analyses

For statistical analysis, the non-parametric McNemar

test for dependent binary indicators was used.

Statistical processing and evaluation of the results of

neuroimaging studies of each patient individually, as

well as their group totality (resting state fMRI data)

were carried out using the CONN v.18 software

package (Functional connectivity toolbox), designed

to determine the relationships between different parts

of the brain, statistical mapping of activation zones,

determining the structure of various resting state

networks and functional networks of the brain.

3.5 Results

Against the background of the course of leech therapy

in patients with asymptomatic carotid stenosis, a

significant improvement was noted in the assessment

of complaints. There was no deterioration in the

condition of patients, adverse and allergic reactions

during treatment. The improvement ranged from

16.67% to 100%, on average - 58.35%. Statistically

significant changes in the state were observed

according to the following indicators - aching,

paroxysmal and aching, unilateral, bilateral, and

overall headache; unsystematic, instantaneous, short-

term, and generally dizziness; opto-vestibular

syndrome and transient visual disturbances.

Improvement in 100% of cases was achieved by the

following indicators: throbbing, persistent headache;

systemic, systemic in combination with non-

systemic, prolonged dizziness.

Similar positive dynamics in evaluating

complaints of headaches and dizziness, noise in the

head and in the ears was noted by us and a number of

other authors in patients with chronic vertebral-

basilar insufficiency, hypertensive

angioencephalopathy, posthypoxic encephalopathy

(Portik O.A., Efimtsev A.Yu. et al, 2019; Pospelova

M.L, 2010; Frolov 2006).

Analyzing the functional MRI data, when

performing an intergroup statistical analysis (two-

sample t-test, comparing the state of rest before

treatment and after a course of leech therapy) with the

choice of the medial prefrontal cortex (MPFC) as the

ROI, we determined the enhancement of the positive

functional connections of MPFC with zone 10, right

cerebellum, with cerebellar vermis. Such changes of

connectom correlate with clinical data on a decrease

in the severity of vestibular disorders in this group of

patients.

Region of interest - cerebellar area. Demonstrated

positive FC with right and left hemisphere of the

cerebellum (8 area), the vermis cerebellum, the

precuneus, angular gyri and posterior divisions of the

cingulate gyrus (part of the default mode network)

(Figure 1).

When performing an analysis based on graph

theory with global efficiency assessment after a

course of leech therapy, stable functional

relationships between the middle temporal gyrus

(posterior, right), upper temporal gyrus (anterior,

right) and lower temporal gyrus were determined

comparing to the results of the study before the start

Analysis of Functional Connectivity When using Complementary Methods of Treatment in Patients with Asymptomatic Carotid Stenosis

375

Figure 1: Cerebellar network. Intergroup comparison.

of treatment (temporal-occipital departments, left),

lingual network, visual network, cerebellar vermi,

zone 6 of the right hemisphere of the cerebellum, pole

of the occipital lobe. At the same time, the degree of

severity of activation of the lingual network (upper

and lower frontal gyrus on the right) was decreased

(Figure 2, Table 1).

Figure 2: Maps of functional connectivity. Graph theory

results.

There was an increase of the negative functional

connections of MPFC with the left middle frontal

gyrus and a weakening of the negative functional

connections of MPFC with the right parahippocampal

gyrus p<0.001 (Figure 3).

Table 1: The degree of activations severity.

ROI beta T

-unc

-FDR

Networ

0.00 -0.98 0.822939 0.931425

MTG r 0.05 2.95 0.008122 0.931425

aSTG

0.07 2.48 0.017570 0.931425

Visual

Occi

ital

0.05 2.24 0.026075 0.931425

OP l 0.03 2.19 0.028042 0.931425

mis 6 0.04 2.03 0.036683 0.931425

toITG l 0.06 1.98 0.039213 0.931425

Cereb6

0.05 1.85 0.048780 0.931425

Figure 3: Intragroup comparison of the subjects before and

after a course of treatment. The changes that occur after

treatment are shown. Activation sites combined with

anatomical images of the head — brain regions positively

functionally associated with MPFC are mapped in red, and

negatively functionally associated with MPFC are mapped

in blue (p<0,001).

The analysis of functional MRI showed that after

the course of leech therapy, the activation of the main

structures of the salience network and the executive

control network was noted. The functional

connections of MPFC — the area of the brain

responsible for controlling and making decisions with

the cerebellum — increased, which was clinically

manifested in a decrease in vestibular disorders, and

the functional connections with the left middle frontal

gyrus decreased, which may indirectly indicate a

decrease in the inhibitory component of the network.

In patients with chronic cerebrovascular accident,

cerebral microangiopathy, there is a gradual loss of

inter- and intrahemispheric functional connections

between the structures of the salience network and the

executive control network, which is the functional

NDNSNT 2020 - Special Session on Non-invasive Diagnosis and Neuro-stimulation in Neurorehabilitation Tasks

376

MRI equivalent of the disconnection phenomenon

(Dobrynina, 2018). After a course of leech therapy,

the connectivity of the leading structures of the brain

significantly increased, which is a morphological and

functional indicator of improving brain functioning

and improving cognitive, emotional and behavioral

disorders in patients with asymptomatic carotid

stenosis.

When assessing the colorability and safety of the

therapy, no hemorrhagic events during the treatment

(hemorrhagic stroke, retinal hemorrhage,

gastrointestinal bleeding, hemorrhoids, nose, uterine

bleeding) were noted.

As a result, we can talk about a significant positive

effect of the leech therapy course on the complex of

complaints and indicators of brain connectivity in

patients with asymptomatic carotid stenosis.

4 CONCLUSIONS

The study of connectome provides new approaches to

the analysis of integrative brain function, and to

assessment of the treatment effectiveness. A course

of leech therapy significantly altered the functional

connectivity of the brain in patients with

asymptomatic carotid stenosis.

CONFLICT OF INTERESTS

The authors declare no conflict of interest.

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