MitraClip less effective than Mitral Valve Surgery: “Heart Team” approach recommended

The results of the first randomised controlled trial comparing percutaneous mitral valve repair against conventional mitral valve surgery was presented recently at the American College of Cardiology Foundation Annual Meeting and published in the New England Journal of Medicine.
The EVEREST II Trial randomised 279 patients with grade 3+ or 4+ mitral regurgitation (MR) to receive either a MitraClip (Abbott Vascular) (184 patients) or conventional mitral valve surgery (95 patients). Following randomisation, 3% of those randomised to receive a MitraClip and 16% of those randomised to surgery withdrew consent for treatment and did not receive any treatment. Of those treated with surgery, 14% underwent mitral valve replacement and 86% mitral valve repair. The MR was of degenerative aetiology in 73% and functional in 27%. The primary composite end point for efficacy was freedom from death, from surgery for mitral valve dysfunction, and from grade 3+ or 4+ MR at 12 months. This was better in the surgical group in the intention‐to‐treat analysis (73% vs 55%, p=0.007) despite the higher proportion of patients in the surgical group who did not receive any treatment. There were similar deaths in both groups (6%).
20% of patients in the MitraClip group subsequently required surgery compared to 2% in the surgical group requiring repeat surgery. At one year, the surgical group had greater reduction in MR severity (p<0.001) and greater reduction in LV volumes (p=0.004). 76% of patients in the surgical group (including those who did not have any treatment) had none or mild MR compared to only 43% in the MitraClip group. The surgical group also had less recurrent 3+ or 4+ MR at 12 months (4% vs 19%). Both groups showed improved NYHA functional class and quality of life measures compared to baseline.  Major adverse events at 30 days were higher in the surgical group (48% vs 15%, p<0.001) due mainly to an increased need for blood transfusions (53.2% vs 8.8%, p< 0.001) and mechanical ventilation greater than 48 hours (4% vs 0%, p=0.02). Excluding the need for blood transfusions, the rate of major adverse events at 30 days was 5% in the MitraClip group and 10% in the surgical group (p=0.23). An accompanying editorial commented that the “modest reduction in regurgitant severity (in the MitraClip group) might be associated with favourable short‐term and mid‐term outcomes, but surgical series suggest that residual mitral regurgitation predicts adverse long‐term clinical outcomes.” The editorial further commented that “we need to be sure that we do not sacrifice proven long‐term effectiveness for short term issues, such as convenience, invasiveness, or reversible procedural complications. The goal is to make the patient feel better and live longer.”   The editorial also called for a multidisciplinary team consisting of a non‐procedural valve disease specialist, an interventional cardiologist and a cardiac surgeon to review each patient being considered for MitraClip therapy, with the panel’s recommendation being based on documentation of severe valve dysfunction and indications for intervention, a patient‐specific procedural risk assessment, expected anatomical and functional results, expected improvement in clinical symptoms and quality of life, potential medication changes (including anticoagulation), long‐term outcome data on survival and repeat procedures, and preferences of the patient. This “heart team” concept has recently been recommended by the ESC and EACTS for myocardial revascularisation. A recent joint report from the STS and the ACC recommended extension of this “heart team” concept to patients with structural heart disease. The report also recommended the establishment of regional centres of excellence for heart valve diseases with only centres meeting certain criteria performing transcatheter valve interventions, the establishment of a national registry of valvular heart disease to perform long term outcome measurements and comparative effectiveness, establishment of training and credentialing criteria for practitioners in this field, and interpretation of the current evidence by expert consensus documents. The report stated that at present, it is inappropriate to use transcatheter interventions in populations beyond those studied in the randomised trials but that the conduct of further randomised trials in other patient groups is strongly encouraged. The results of the EVEREST II trial are promising but experience with the MitraClip is still early and limited. Longer term results are awaited. Source: K.M. John Chan FRCS CTh, John R. Pepper FRCS 9 July 2011

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