Incidence, Etiology and Mechanisms of Mitral Regurgitation Among an Adult Population

Background:
Mitral regurgitation (MR) is a common valve disease that affects adversely patient morbidity and mortality. New therapeutic modalities are available relating to the mechanism of MR. We aim to study the incidence, etiology and mechanisms of the disease among an adult population.

Methods:
Data was obtained from consecutive patients referred to an Echo lab at a tertiary medical center for any reason for a period of 3 months (from April to July 2016). If a subject underwent > one echocardiographic study (trans-thoracic or trans-esophageal), only the first one was considered for analysis.

Results:
Data was collected from a cohort of 4113 subjects, older than 18 years, age 59 ± 13 years, 52% females. MR of any severity was found in 35% (1421 out of 4113) of the cases. The table depicts demographic characteristics of MR patients and mechanisms. Fibro-elastic deficiency was the most common etiology (39%) among primary MR, and calcification (35%), rheumatic (8%), and miscellaneous (18%) others less frequent causes. Secondary MR was more frequent, although not statistically significant among subjects with moderate/severe MR (28%) than in the whole MR group (24%). LV ejection fraction was significantly lower in subjects with secondary MR compared to those with primary MR (34.7% and 52.5%, respectively [p= 0.0023]). The most frequent mechanism responsible for secondary MR was a limited systolic excursion of at least one of the mitral leaflets (type IIIB according to Carpentier classification) (62%). The remainder of the cases were due to mitral annulus dilatation (type I).

Conclusions:
Mitral regurgitation, including the most severe degree of the disease is common among an adult population. The main reason for mitral dysfunction is an organic lesion of the mitral apparatus, some of which are suitable to be treated with the new percutaneous methods of MR repair.