A.V. VASILYEVA^1, 2, YU.E. TEREGULOV^1–3, M.M. MANGUSHEVA³, F.N. MUHAMETSHINA^1–3, M.S. MAKSIMOVA¹, P.A. KASHKIN²

 ¹KSMA — branch campus of the FSBEI FPE RMACPE MOH Russia, Kazan

²Republic Clinical Hospital, Kazan

³Kazan State Medical University, Kazan

Contact details:

Vasilyeva A.V. — Assistant Lecturer of the Department of Functional Diagnostics, doctor of functional diagnostics

Address: 49 Butlerov St., 420012 Kazan, Russian Federation, tel.: +7-927-249-16-36, e-mail: ann1443@mail.ru

Atrial fibrillation (AF) increases the risk of ischemic stroke by an average of 0.2 to 20% per year. Both AF and brachiocephalic arteries (BCA) stenosis can be sources of microemboli in the cerebral vessels.

The purpose is to evaluate the relationship between microembolic signals (MES) and intracardiac hemodynamic parameters in patients with AF.

Material and methods. The study included 57 patients with atrial fibrillation (AF) aged 41–77 years (mean age 61 ± 11 years), including 39 men (68%) and 18 women (32%). All patients underwent transthoracic echocardiography, transesophageal echocardiography, duplex scanning of the brachiocephalic arteries, and transcranial Doppler monitoring in embolodetection mode.

Results. A relationship was found between the number of microemboli and the left atrium (LA) volume, the velocity in the aorta and the left ventricular (LV) outflow tract, the severity of spontaneous echo contrast (SEC) in the left atrial appendage (LAA), and the rate of its emptying (ER). A significant relationship was found between the LA volume and the amount of «soft» microemboli. The greatest embologenicity was observed in patients with grades 3–4 SEC, as well as in patients with a thrombus in the LAA. A correlation was determined between «dense» emboli and blood flow velocity in the LV outflow tract.

Conclusions. The amount of «soft» microemboli in patients with AF is directly related to LA volume and the SEC severity, and is inversely related to LAA emptying velocity. The detection of «dense» microemboli is associated with the atherosclerotic plaque burden (APB) according to Plaque RADS and was observed only in RADS III. It is also directly related to left ventricular outflow tract blood flow velocity.

Key words: atrial fibrillation, spontaneous contrast phenomenon, cerebral microembolism, transcranial Doppler monitoring with microembolodetection, Plaque RADS

REFERENCES

1. Arakelyan M.G., Bokeriya L.A., Vasil′yeva E.Yu. et al. Atrial fibrillation and flutter. Clinical guidelines-2020. Rossiyskiy kardiologicheskiy zhurnal, 2021, vol. 26, no. 7, p. 4594 (in Russ.). DOI: 10.15829/1560 4071-2021-4594
2. De Fritas G.R., Boguslavskiy Dzh. Primary prevention of stroke. Zhurnal nevrologii i psikhiatrii im. S.S. Korsakova, 2001, no. 1 / Insul′t: prilozheniye k zhurnalu, pp. 7–31 (in Russ.).
3. Kushakovskiy M.S. Fibrillyatsiya predserdiy (prichiny, mekhanizmy, klinicheskiye formy, lecheniye i profilaktika) [Atrial fibrillation (causes, mechanisms, clinical forms, treatment and prevention)]. Saint Petersburg: IKF «Foliant», 1999. 176 p.
4. Sumin A.N. et al. The phenomenon of spontaneous echo contrast in the left atrium in persistent atrial fibrillation: what influences its severity? Kardiologiya, 1999, no. 2, pp. 60–65 (in Russ.).
5. Al-Saady N.M., Obel O.A., Camm A.J. Left atrial appendage: structure, function, and role in thromboembolism. Heart, 1999, vol. 82, pp. 547–554.
6. Shirani J., Alaeddini J. Structural remodeling of the left atrial appendage in patients with chronic non-valvular atrial fibrillation: Implications for thrombus formation, systemic embolism, and assessment by transesophageal echocardiography. Cardiovasc. Pathol, 2000, vol. 9 (2), pp. 95–101.
7. Khan LA. Atrial stunning: basics and clinical considerations. Int. J. Cardiol, 2003, vol. 92, pp. 113–128.
8. Mukharlyamov N.M. et al. Klinicheskaya ul′trazvukovaya diagnostika: rukovodstvo dlya vrachey [Clinical ultrasound diagnostics: a guide for physicians]. Moscow: Meditsina, 1987. Vol. 1. Pp. 7–179.
9. Fatkin D. et al. Relations between LAA blood flow velocity, spontaneous echocardiographic contrast (SEC) and thromboembolic risk in vivo. J. Am. Coll. Cardiol, 1994, vol. 23, pp. 961–969.
10. Saba L., Cau R., Murgia A., Nicolaides A.N. et al. Carotid Plaque-RADS: a novel stroke risk classification system. JACC Cardiovasc Imaging, 2024, vol. 17 (1), rr. 62–75.
11. Georgiadis D. et al. Intracranial microembolic signals in 500 patients with potential cardiac or carotid embolic source and in normal controls. Stroke, 1997, vol. 28, pp. 1203–1207.
12. Grosset D.G. et al. Doppler emboli signals vary according to stroke subtype. Stroke, 1994, vol. 25, pp. 382–384.
13. Sliwka U. et al. Occurrence of transcranial doppler high-intensity transient signals in patients with potential cardiac sources of embolism. A prospective study. Stroke, 1995, vol. 26, pp. 2067–2070.
14. Abbott A., Chambers B.R., Stork L. et al. Embolic signals and prediction of ipsilateral stroke or transient ischemic attact in asymptomatic carotid stenosis. A multicenter prospective cohort study. Stroke, 2005, vol. 36, pp. 1128–1133.
15. Vasil′yeva A.V., Teregulov Yu.E. Mangusheva M.M. et al. Biophysical characteristics of microemboli in patients with acute cerebrovascular accidents. Prakticheskaya meditsina, 2014, vol. 3, no. 14 (in Russ.).
16. Consensus Committee of the Ninth International Cerebral Hemodynamics Symposium. Basic identification criteria of Doppler microembolic signal. Stroke, 1995, vol. 26, p. 1123.
17. Erbel R. et al. Detection of spontaneous echocardiographic contrast within the left atrium by transesophageal echocardiography: spontaneous echocardiographic contrast. Clin. Cardiol, 1986, vol. 9 (6), pp. 245–252.
18. Fatkin D. et al. Relations between LAA blood flow velocity, spontaneous echocardiographic contrast (SEC) and thromboembolic risk in vivo. J. Am. Coll. Cardiol, 1994, vol. 23, pp. 961–969.
19. Chimowitz M.I. et al. Left atrial spontaneous echo contrast is highly associated with previous stroke in patients with atrial fibrillation or mitral stenosis. Stroke, 1993, vol. 24, pp. 1015–1019.
20. Pollick C., Taylor D. Assessment of left atrial appendage function by transesophageal echocardiography. Implications for the development of thrombus. Circulation, 1991, vol. 84, pp. 223–231.
21. The Stroke Prevention in Atrial Fibrillation Investigators Committee on echocardiography. Transesophageal echocardiographic correlates of thromboembolism in high-risk patients with nonvalvular atrial fibrillation. Ann. Intern. Med, 1998, vol. 128, pp. 639–647.
22. Vasil′yeva A.V. Risk of cerebral microembolism depending on the type of atherosclerotic plaques in the carotid arteries according to the RADS classification. Meditsinskiy alfavit, 2025, no. 24, pp. 36–41 (in Russ.). DOI: 10.33667/2078563120252436–41
23. Shlyk E.V. Mikroemboliya v tserebral′nyye arterii v ostreyshem periode ishemicheskogo insul′ta: dis. …kand. med. nauk [Microembolism in cerebral arteries in the acute period of ischemic stroke. Dis of PhD med. sciences]. Moscow: NII tserebrovaskulyarnoy patologii, 2012.