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[Does mitral insufficiency prevent spontaneous contrast phenomenon and formation of thrombi in the left atrium?]
M C Adam1, C Tribouilloy, A Mirode
1Département de cardiologie, CHU hôpital Sud, Amiens.
Insights
Severe mitral regurgitation significantly reduces the risk of left atrial spontaneous echo contrast and thrombosis. This finding explains the lower incidence of systemic embolism in patients with severe mitral regurgitation.
Area of Science:
- Cardiology
- Echocardiography
- Thrombosis Research
Background:
- Left atrial spontaneous echo contrast and thrombosis are risk factors for systemic embolism.
- The impact of mitral regurgitation (MR) on these phenomena requires further investigation.
Purpose of the Study:
- To assess the influence of severe mitral regurgitation (grades 3-4) on the prevalence of left atrial spontaneous echo contrast and thrombosis.
- To explore the relationship between severe MR and embolic events.
Main Methods:
- Retrospective analysis of 2,180 patients undergoing echocardiography.
- Patients were grouped based on the severity of mitral regurgitation (absent vs. grades 3-4).
- Prevalence of spontaneous echo contrast, left atrial thrombosis, and embolic events were compared between groups.
Main Results:
- Severe mitral regurgitation was associated with significantly lower rates of spontaneous echo contrast (0.6% vs. 11.2%) and left atrial thrombosis (0.6% vs. 4.2%).
- Patients with severe MR had a lower incidence of ischemic cerebrovascular accidents, transient ischemic attacks, and systemic embolism.
- Higher prevalence of atrial fibrillation and enlarged left atrial dimensions were observed in patients with severe MR.
Conclusions:
- Severe mitral regurgitation is a protective factor against left atrial spontaneous echo contrast and thrombosis.
- The reduced risk of embolic events in severe MR is likely due to the diminished occurrence of these intra-atrial phenomena.
- Findings were consistent even after excluding patients with mitral stenosis or valve prosthesis.
Abstract:
The aim of this study was to assess the influence of mitral regurgitation on the prevalence of left atrial spontaneous echo contrast and thrombosis in 2,180 consecutive patients undergoing transthoracic and transoesophageal echocardiography. Two groups of patients were defined according to the absence (group I) or presence (group II) of grades 3 or 4 mitral regurgitation quantified by transoesophageal echocardiography. Group II was associated with a statistically significant lower frequency of spontaneous echo contrast (0.6 vs 11.2%; p < 0.0001), left atrial thrombosis (0.6 vs 4.2%; p < 0.03), ischaemic cerebrovascular accidents (1.2 vs 21%; p < 0.0001), transient ischaemic attacks (0 vs 12%; p < 0.0001) and systemic embolism (0 vs 4.6%; p < 0.01). Conversely, the prevalence of atrial fibrillation was higher in group II (28 vs 19%; p < 0.01) and there were more patients with left atrial dimensions > or = 5.5 cm (16 vs 6.7%; p < 0.0001). When mitral stenosis and valve prosthesis were excluded, there were no cases of spontaneous echo contrast (8.3 vs 0%; p < 0.001) or left atrial thrombosis (2.9 vs 0%; p < 0.05) in the group with grades 3 or 4 mitral regurgitation. The phenomenon of left atrial spontaneous echo contrast and/or thrombosis is rare in patients with grade 3 or 4 in native mitral valve regurgitation and explains the low incidence of systemic embolism in these cases.