Left atrial thrombus in Echocardiography

Thrombus,left atrial, echo, pathology

1. Ok LA THROMBUS Ms.Afrin , department of Cct

2. Definition

3. DETERMINANTS

4. DETERMINANTS

5. EPIDEMIOLOGY Patients with severe symptomatic MS, 50% or more have chronic AF. The incidence of thromboembolic complications is higher in patients with rheumatic mitral stenosis and is a major cause of morbidity and mortality. The left atrium and left atrial appendage are well recognised sites of clot formation in these patients . Patients with a clot in the left atrium and left atrial appendage had a higher incidence of systemic embolization.

6. EPIDEMIOLOGY LA thrombi are reported to occur in 26-33% of patients with severe mitral stenosis . LA thrombi were found in 20% of patients who underwent surgery for mitral stenosis . The presence of LA thrombi was associated with a threefold increase in embolic events. Fifty percent of LA thrombi in patients with rheumatic valvular disease, and nearly 90% of LA thrombi in patients with non-valvular AF are limited to the LA appendage

7. CLASSIFICATION

8. CLASSIFICATION

9. TYPES( Based on morphology )

10. Pathophysiology Rudolf Virchow postulated that the pathophysiology of thrombus formation forms a triad which includes abnormalities of the vessel wall, blood stasis, and a hypercoaguable state. This triad can be applied to thrombus formation in atrial fibrillation, where the structural change occurs at the left atrial appendage , undergoing a resultant hypercoaguable trans formation due to increased blood stasis and an inflammatory milieu

11. Pathophysiology

12. ECHOCARDIOGRAPHIC EVALUATION Transesophageal Echocardiography and Intracardiac Echocardiography. TOE is considered the gold standard modality for diagnosis of LAA thrombi with a sensitivity and specificity of 95%–100%

13. The LAA is a small, pyramidal structure, which is situated on the lateral aspect of the left atrium (LA), extending between the pulmonary artery above and the left ventricle (LV) below. It is usually a mul - tilobed structure.. Although the LAA can be visualized on transthoracic echocardiography also, in most patients a detailed assessment is not possible due to the posterior location of the LAA. In contrast, TEE, with the close proximity of the transducer to the LAA, allows excellent imaging of the LAA and is therefore mandatory whenever an as- sessment of LAA is sought. ECHOCARDIOGRAPHIC EVALUATION

14. TEE VIEWS On TEE, the LAA is best visualized in the mid- esophageal two-chamber view (80-100°) and the mid- esophageal aortic valve short-axis view (30-60°). In most pa- tients , these two views allow satisfactory imaging of the LAA and are therefore the recommended views for this purpose

15. The echo assessment of a cardiac thrombus should include a description of its:
size (measure its dimensions)
location
shape (e.g. Flat, protruding, spherical)
surface appearance (e.g. Regular, irregular)texture (e.g. Solid, layered, calcified) mobility (mobile or fixed)
associated features (e.g. Dilated LA, LV aneurysm). ECHOCARDIOGRAPHIC EVALUATION

16. LEFT ATRIUM DIMENSION LA diameter is measured at end-systole in the parasternal long axis view, using either 2D or M-mode imaging

17. LEFT ATRIUM DIMENSION

18. ECHOCARDIOGRAPHIC EVALUATION Compared with a myxoma , a thrombus usually has a more irregular shape. Thrombus usually attaches to the endocardium via a broad base rather than a pedicle, and is consequently less mobile. A large proportion of LA thrombi are within the LA appendage, which can be difficult to inspect fully on TTE. The appendage is, however, clearly seen on TOE. It is important to try to distinguish between thrombus and the pectinate muscles, the normal muscle ridges found on the walls of both atria and the appendage. Pectinate muscles are immobile and run in bands; thrombus is usually more rounded and mobile.

19. Stasis of blood within the heart (and sometimes even the aorta) can be evident as ‘spontaneous echo contrast. This has the appearance of a swirling ‘cloud’ of tiny particles, hence it is sometimes referred to as ‘smoke’. Although it is most often (and mostly clearly) seen during TOE studies, it can also be observed during TTE. Spontaneous contrast is caused by echo reflections from aggregations of red blood cells moving at low velocity, and it is most often observed in the LA in patients in AF, particularly if they also have mitral stenosis. It indicates an increased risk of thrombus formation. SPONTANEOUS ECHO CONTRAST

20. THROMBUS IN OTHER CHAMBERS Thrombus in the LV normally occurs in association with an area of wall motion abnormality and/or aneurysm formation, commonly the apex The echo texture of the thrombus is usually distinct from the adjacent myocardium. With the passage of time, the thrombus may become organized and layered, and there may be associated calcification. TTE is better than TOE for the detection of ventricular thrombus, as the ventricle is closer to the probe on TTE imaging

21. Thrombus in the right heart is less commonly found, and may represent a thromboembolism that has arisen in the peripheral veins and is ‘in transit’ to becoming a pulmonary embolism. Another cause of right heart thrombi is the presence of devices such as pacing/defibrillator leads or intravascular catheters, which can act as a focus for thrombus formation. THROMBUS IN OTHER CHAMBERS