Just as percutaneous therapy for coronary artery disease has revolutionized the management of patients with atherosclerosis and offered an alternative to traditional surgical management, percutaneous treatments are now becoming established for valvular heart disease.  While percutaneous aortic valves are becoming increasingly common-place, treatment options for mitral regurgitant disease remain limited. One such option in development is the MitraClip (Abbot Vascular) which, via a trans-septal approach, grasps and approximates the edges of the mitral leaflets at the origin of the regurgitant jet, reducing its severity.

In the industry-sponsored EVEREST II trial 279 patients with moderately severe or severe (grade 3+ or 4+) mitral regurgitation were randomly assigned in a 2:1 ratio to undergo either percutaneous MitraClip implantation or conventional surgical repair/replacement. The primary composite end point was freedom from death, surgery for mitral-valve dysfunction, and from grade 3+ or 4+ mitral regurgitation at 12 months.  The primary safety end point was a composite of major adverse events within 30 days.

The study failed to show equipoise, with rates of the primary end point of 55% in the clip group and 73% in the surgery group (P=0.007). This difference was driven primarily by the need for mitral surgery due to clip inadequacy, while survival and grade 3+ or 4+ regurgitation at 12 months did not differ significantly between groups.  From a safety point of view, major adverse events occurred in 15% of patients in the percutaneous-repair group and 48% of patients in the surgery group at 30 days (P<0.001) although this was mainly due to an increased need for blood transfusion in the surgical group.  At 12 months, both groups had improved left ventricular size, New York Heart Association functional class, and quality-of-life measures, as compared with baseline.

Conclusions:

In this moderate-sized phase III study, percutaneous repair was less effective at reducing mitral regurgitation than traditional surgery.  However, when successful, this minimally invasive approach led to similar improvements in clinical outcomes and had a superior safety profile.  Longer-term outcomes remain to be established.

• Feldman T, Foster E, Glower DG et al. Percutaneous repair or surgery for mitral regurgitation. N Engl J Med 2011 ;364:1395-406.