Corresponding Author:
Eduardo de Marchena MD, FACC, FACP, FSCAI
Associate Dean for International Medicine
Professor of Medicine & Surgery
Director, Interventional Cardiology
Program Director, Eberhard Grube International Structural Heart Training
Program
University of Miami Miller School of Medicine, University of Miami
Office Phone number 305-243-9200
1400 NW 10th Avenue Dominion Tower Suite 206A Miami
Fl. 33136
Microinvasive Mitral Valve Surgery: A New Frontier to Tackle Mitral
Regurgitation
Solomon Seifu, MD; Eduardo de Marchena, MD
Mitral regurgitation can be caused by either primary mitral valve
apparatus disease process which is called primary MR/degenerative mitral
valve disease or secondary causes from ventricular remodeling which is
called functional MR. The mitral valve apparatus includes the valve
leaflets, annulus, chordae tendineae, and papillary muscles. The left
atrium and ventricle are also integrally involved with mitral valve
function. Treatment of mitral valve regurgitation therefore should
primarily focus on the specific pathophysiologic process leading to the
MR.
Treatment of mitral regurgitation has evolved from an open-heart
surgical repair to microinvasive surgical repair and transcatheter
repair. Surgical mitral valve repair techniques can involve a simple
edge-to-edge repair using an Alfieri’s stitch or use adjunctive
artificial chord replacement and ring annuloplasty. Catheter-based
mitral valve repair utilizes less invasive approaches with less
procedural morbidity and mortality. Percutaneous annuloplasty can be
achieved indirectly via the coronary sinus or directly from retrograde
left ventricular access. Catheter-based leaflet repair is accomplished
using an implantable clip to mimic the surgical edge-to-edge technique
[1].
In this issue of Journal of Cardiac surgery, D’Onofrio et al [2],
the authors review the technologies intended to treat mitral
regurgitation (MR) through transapical approach, including annuloplasty
and chordal-repair options. They reviewed the procedural steps and
clinical results of the transcatheter transapical mitral valve
annuloplasty (AMEND mitral repair implant) and transcatheter transapical
chordal repair systems (Neochord DS 1000 device and Harpoon Mitral Valve
Repair System).
The AMEND (Valcare Medical, Herzliya Pituach, Israel) is a transcatheter
device for direct mitral annuloplasty. It is a D-shaped ring with
anchoring capabilities that mimics the annuloplasty rings used in
open-heart surgery and allows for anterior-posterior reduction. The
procedure is performed under general anesthesia through transapical
approach with the guidance of transesophageal echocardiography and
fluoroscopy. Implantations performed in a mix of 14 functional and
degenerative MR patients showed reduction of MR to ≤ 2+. A 20% mean
reduction of anteroposterior diameter was achieved, no residual
pulmonary flow reversal in all cases was reported, mean reduction of the
jet area was 74%.
The transcatheter chordal repair technologies reviewed in this
manuscript are primarily intended to treat degenerative mitral
regurgitations. The Neochord DS 1000 device (Neochord Inc, St. Louis
Park, MN) is a transapical beating heart mitral valve repair system with
a neochord implantation. The procedure is performed under general
anesthesia through the left ventricular apical access with real time
transesophageal guidance. The TACT Trial (Transapical Artificial Chordae
Tendinae) showed for the first time that the NeoChord DS1000 system is
technically safe and feasible [3]. The acute procedural success was
reduction of MR to ≤ 2+ in 86.7% of patients. The second transcatheter
chordal device discussed is the Harpoon Mitral Valve Repair System
(Edwards Lifesciences, Irvine, CA). It is performed under general
anesthesia and through transapical access with real time transesophageal
echocardiography guidance. The TRACER trial (Mitral
TransApicalNeoChordal Echo-Guided Repair) demonstrated the safety and
effectiveness of this device with MR reduction to moderate or less, met
in 90% of patients [4].
The authors should be applauded for the excellent review of these three
innovative technologies of annuloplasty and chordal repair targeting the
different components of the mitral valvular apparatus. Transcatheter
mitral valve repair technologies are becoming more and more refined in
recent years demonstrating a promising clinical success for the
treatment of severe mitral regurgitation.
References:
1. Feldman T, Cilingiroglu M. Percutaneous leaflet repair and
annuloplasty for mitral regurgitation. J Am Coll Cardiol.
2011;57(5):529-537.
2. D’Onofrio, Augusto, et al. ”Transapical mitral valve repair
procedures: primetime for microinvasive mitral valve surgery.” Authorea
Preprints (2021).
3. Seeburger J, Rinaldi M, Nielsen SL, et al. Off-pump transapical
implantation of artificial neo-chordae to correct mitral regurgitation:
the TACT Trial (Transapical Artificial Chordae Tendinae) proof of
concept. J Am Coll Cardiol. 2014;63(9):914-919.
4. Gammie JS, Bartus K, Gackowski A, et al. Beating-Heart Mitral
Valve Repair Using a Novel ePTFE Cordal Implantation Device: A
Prospective Trial. J Am Coll Cardiol. 2018;71(1):25-36.