Click Valvar #713 - Conceito de proporcionalidade da regurgitação mitral
·4 min
The episode begins by questioning the importance of the left atrium in mitral regurgitation and the relationship between regurgitation and atrial volume. It introduces the concept of proportionality in mitral insufficiency, developed from the COAPT and MITREFAR trials, which studied patients with mitral regurgitation and cardiac insufficiency. These trials provided information about mortality outcomes following mitral clipping based on this proportionality concept. The core idea involves comparing mitral regurgitation volume to ventricular volume to determine if regurgitation is disproportionate. Cases with regurgitation too large relative to ventricle size are considered disproportionate, and mitral clipping after therapeutic optimization showed mortality benefits. This concept has spread within clinical cardiology, particularly for symptomatic heart failure cases with mitral regurgitation. A key unresolved point is understanding the left atrium's behavior in this pathophysiology. While the atrium accommodates regurgitation to prevent retrograde filling pressure rise, different cases show varied evolution and clinical manifestations. The reading about mitral clipping differs from ventricular findings despite the same volume overload. Mitral insufficiency causes volume overload leading to left cavity dilation, which is initially adaptive but becomes irreversible when surpassing physiological limits. Ultimately, the ventricle loses contractile power and the atrium dilates, potentially evolving into atrial fibrillation. The COAPT trial indicated that small ventricles with large regurgitations deserve intervention attempts. However, the atrium's relationship shows it serves as a prognostic marker rather than an intervention indicator. Patients with very large atria and mitral regurgitation who underwent mitral clipping had higher heart failure incidence. The relationship between these variables predicts outcomes more accurately than either variable alone. Patients with more dilated atria generally have worse evolutions. The study cohort was similar to COAPT but included mixed functional etiology cases with atrial dilation and mitral ring changes, pointing to worse evolution patients. Some cases with mitral-far profile inclusion may have influenced findings by representing more advanced pathology. These data reinforce that functional impact of valvopathies is more important than anatomical readings.
