Aortic stiffness: an old concept for new insights into the pathophysiology of functional mitral regurgitation.

Functional mitral regurgitation (FMR) is thought to be linked with ventricular afterload. However, the relation between aortic stiffness, which is a main determinant of ventricular afterload, and quantitatively assessed mitral regurgitation is unknown. A total of 175 patients (age 61 ± 13; 85 \% male) with left ventricular (LV) systolic dysfunction were studied consecutively. Left ventricular volumes, ejection fraction, and LV outflow tract stroke volume were measured. Aortic pulse wave velocity (PWV), a known marker of aortic stiffness, was determined using Doppler flow recordings as the distance (d) traveled by the pulse wave, measured over the body surface as the distance between the two recording sites, divided by the time (t) taken by the pulse wave to travel from the descending aorta to the abdominal aorta. Mitral effective regurgitant orifice (ERO), regurgitant volume (RV), and fraction (RF) were measured using the proximal isovelocity surface area method. The mean PWV was 6.0 ± 3.5 m/s (range 2.6-25). PWV was significantly associated with ERO (r = 0.35; p < 0.0001), RV (r = 0.36; p < 0.0001) RF (p = 0.41; p < 0.0001). The association of PWV with each variable of mitral regurgitation was independent of LV volume, cardiac output, and systemic vascular resistance. Aortic stiffness is an important determinant of the severity of FMR. Aortic stiffness should be considered an important therapeutic target in patients with LV dysfunction in order to ameliorate both LV systolic and diastolic function and mitral regurgitation.