Mitral subvalvular plasty for chronic ischemic mitral regurgitation: a preliminary experimental model

Restrictive annuloplasty remains the most widespread technique for the correction of chronic ischemic mitral regurgitation (IMR). However, this technique only partially corrects the underlying pathophysiology and does not address the restricted leaflet motions during systole that result from progressive left ventricular (LV) remodeling.

A novel experimental model of IMR was developed using an isolated pig heart placed on a hydrodynamic test-stand. A T-shaped LV patch was sutured onto the posterior wall of the left ventricle to simulate LV dilatation secondary to post-MI remodeling.

Using this model, a novel technique of subvalvular mitral valvuloplasty was described that reduces the distance between the posterior mitral annulus and the papillary muscle base and appears to be effective in eliminating IMR. Pledgetted 2-0 non-absorbable sutures were placed at the base of one papillary muscle, then through the other papillary muscle and then brought to the posterior mitral annulus. The same sequence was repeated in the other direction. A specific formula was then used to calculate the length of the subvalvular support prior to suture tying.

Subvalvular support of the mitral apparatus in chronic IMR can be achieved using this simple method, which appears to be effective in eliminating IMR. Further data relating to the use of this technique in the clinical setting as an adjunct to mitral annuloplasty are forthcoming.