Percutaneous Mitral Valve Repair for Mitral Regurgitation

Abstract

Mitral regurgitation (MR) associated with, ischemic, and degenerative (prolapse) disease, contributes to left ventricular (LV) dysfunction due to remodeling, and LV dilation, resulting in worsening of MR. Mitral valve (MV) surgical repair has provided improvement in survival, LV function and symptoms, especially when performed early. Surgical repair is complex, due to diverse etiologies and has significant complications. The Society for Thoracic Surgery database shows that operative mortality for a 1st repair is 2% and for re-do repair is 4 times that. Cardiopulmonary bypass and cardiac arrest are required. The attendant morbidity prolongs hospitalization and recovery. Alfieri simplified mitral repair using an edge-to-edge technique which subsequently has been shown to be effective for multiple etiologies of MR. The MV leaflers are typically brought together by a central suture producing a double orifice MV without stenosis. Umana reported that MR decreased from grade 3.6 +/- 0.5 to 0.8 +/- 0.4 (P < 0.0001) and LV ejection fraction increased from 33 +/- 13% to 45 +/- 11% (P = 0.0156). In 121 patients, Maisano reported freedom from re-operation of 95 +/- 4.8% with up to 6 year follow-up. Oz developed a MV "grasper" that is directly placed via a left ventriculotomy and coapts both leaflets which are then fastened by a graduated spiral screw. An in-vitro model using explanted human valves showed significant reduction in MR and in canine studies, animals followed by serial echo had persistent MV coaptation. At 12 weeks the device was endothelialized. These promising results have paved the way for a percutaneous or minimally invasive-off pump mitral repair. Evalve has developed catheter-based technology, which, by apposing the edges of a regurgitant MV, results in edge-to-edge repair. Release of the device is done after echo and fluoroscopic evaluation under normal loading conditions. If the desired effect is not produced the device can be repositioned or retrieved. Animal studies show excellent healing, with incorporation of the device into the leaflets at 6-10 weeks with persistent coaptation. Another percutaneous approach has been to utilize the proximity of the coronary sinus (CS) to the mitral annulus (MA). Placement of a self-compressing device in the CS along the region of the posterior MA has, in canine models, reduced MR and addresses the issues of MA dilation and its contribution to MR. Ongoing studies are underway for both techniques.

Treatment of mitral regurgitation

“…After the implant a regimen of aspirin at a dose of 325 mg daily for 6 months with clopidogrel at a dose of 75 mg daily for 1 month is suggested [2], although this therapy has not been validated.…”

“…The etiology is usually ischemic or dilatative cardiomyopathy [1]. In the former, surgical correction is effective, usually done with MV repair, rather than replacement, and has been associated with first-time operative mortality rates near 2%, and re-operative mortality rates near 8% [2]. The surgical intervention in the functional forms has a worse outcome and is often not indicated.…”

Percutaneous Transvenous Mitral Annuloplasty

“…[23][24][25][26][27]32 We have only experienced the one described event treated with circumflex stenting. No evidence of arterial impingement was observed in any of the subsequent cases in this cohort.…”

“…21 Various investigators have proposed less invasive repair techniques to interrupt the natural history of MR in ischemic heart disease and heart failure. [22][23][24] Current efforts include approaches to directly clip 25 the mitral leaflets or modify the mitral annulus via the coronary sinus 26,27 and various other novel techniques. 28 Preliminary data in both animal models and initial, temporary human studies have demonstrated the potential of the PTMA device (Viacor Inc, Wilmington, Mass) and the method to reduce the mitral annular septallateral dimension and limit MR. 29,30 This report describes initial results and procedure revisions in an intention-toimplant feasibility study.…”

Mechanical Device–Based Methods of Managing and Treating Heart Failure

“…25 Accordingly, numerous catheter-based devices are being developed to perform mitral valve repair percutaneously to reduce risk and allow it to be performed as a sole therapy to treat symptoms of heart failure. 26,27 It is proposed that availability of such devices will allow treatment of more patients, including those at high risk, with reduced procedural morbidity and mortality.…”