Mechanism and severity of mitral regurgitation by transesophageal echocardiography in patients referred for percutaneous valve repair.

Percutaneous mitral valve repair with the MitraClip has been shown to decrease mitral regurgitation (MR) severity, left ventricular volumes, and functional class in patients with severe (3+ or 4+) MR. Determination of which patients are optimal candidates for MitraClip therapy versus surgery has not been rigorously evaluated. Transesophageal echocardiography was prospectively performed in 113 consecutive patients referred for potential MitraClip therapy under the REALISM continued access registry. MR severity was assessed quantitatively in all patients. Mitral valve anatomy and feasibility of MitraClip placement were assessed by transesophageal echocardiography and clinical parameters. MR was degenerative (mitral valve prolapse) in 60 patients (53%), functional (anatomically normal) in 44 (39%), and thickened with restricted motion (Carpentier IIIB classification) in 9 (8%). MR was mild in 19 patients (17%), moderate in 27 (24%), and severe (3 to 4+) in 67 (59%) by Transesophageal echocardiography. MitraClip placement was performed in only 17 of 113 patients (15%); all were successful. Surgical mitral valve repair was performed in 25 patients (22%), mitral valve replacement in 12 (11%). Most patients (59 of 113, 52%) were treated medically, usually because MR was not severe enough to warrant intervention. In conclusion, most patients referred for MitraClip therapy do not have severe enough MR to warrant intervention. Of those with clinical need for intervention, surgery is more often recommended for anatomic or clinical reasons. Three-dimensional transesophageal echocardiography with quantitative assessment of MR severity is helpful in evaluating these patients.