Autopericardial Mitral Valve Reconstruction: How I Do It

2020-04-21T21:03:01Z (GMT) by Prasanna Simha Mohan Rao

In this video, the authors describe their method of autopericardial reconstruction. They had previously done a series of autopericardial mitral reconstruction in 2008-2009 based on the method described by Radu Deac et al and, surprisingly, on follow-up none of the patients had developed structural degeneration over the course of a decade, despite most of them being younger rheumatics. The authors did however find the method required significant attention to detail to prevent valve torsion and had a lower predicted orifice area as it is based geometrically on the frustum of a cone. They decided to do mitral reconstruction based on the normal mitral valve anatomy and use artificial chordae to mimic the normal mitral valve as far as possible.

The authors perform autopericardial mitral valve reconstruction (MVRc) for irreparable and calcified valves. This video shows MVRc done for one such case.

Preoperative transesophageal echocardiography confirmed inoperability. On sternotomy, a large portion of pericardium was harvested from the patient and was cleaned and spread on a plastic sheet and treated with 0.5% glutaraldehyde for eight minutes. Brief tanning with a low glutaraldehyde concentration prevented late calcific degeneration.

The patient was placed on conventional cardiopulmonary bypass, the heart was arrested, and the authors’ standard approach was through the transseptal route. The irreparability of the valve was reconfirmed, and the calcified portion of the valve was excised, preserving as many natural chordae as possible. If chordal apparatus requires excision, the authors create artificial neochordae with 2/0 braided polyester sutures and create a knot tower of 14 knots. This is fixed to the mitral annulus to re-establish annulopapillary continuity and also to prevent excessive stress on the newly reconstructed valve.

After valve excision, the appropriate sizer that passes through the mitral orifice was selected. The authors have made templates with polycarbonate sheets. The templates are based on the normal mitral leaflet dimensions as described by Ranganathan and Lam and Henry Gray. The appropriate template is selected, and this is used to mark the valve on the treated pericardium. The template has slots to mark the chordal insertion points, and these are also marked. Typically, the authors have four chordal insertion points on the anterior and posterior leaflets respectively. The pericardium was cut, and the two free ends were sutured together using 4/0 polyester braided sutures using an interlocking technique to prevent crumpling. Two rows are typically done. This forms the mitral veil. Now using three tacking sutures, the leaflets were tacked on to the ring. The authors then sutured the ring to the leaflets, using a running 4/0 polypropylene suture and it is tied down. The valve preparation is typically done by another operator/assistant at another bench while the valve sutures are being placed.

While the valve was being prepared, annular sutures were taken using 2/0 braided polyester sutures in an everting horizontal mattress technique, including all portions of nonexcised valve. The valve sutures were then passed through the sewing rim of the ring, and the valve was lowered down. Sutures were cut, and the leaflets were checked for free mobility by saline insufflation and manipulation. The valve sutures are now tied down

Now subvalvar reconstruction commenced by placing at each papillary muscle two Goretex CV5 sutures and two 4/0 braided polyester sutures to create eight artificial chordae. The artificial chordae were serially inserted into the chordal insertion points that have been marked on the leaflets with a 5 mm gap between the two arms of the suture. The authors start with the posterior leaflet first and place the GoreTex sutures centrally, and the braided polyester sutures laterally. Small hemoclips were placed on the chordae such that the posterior leaflet chordae length was at the height of the inner rim of the sewing rim. The hemoclips are placed subtending the outer rim in case of the anterior leaflet. Saline insufflation was done to check the valve, and the clips can be adjusted if required. The authors have noted that the clip placement needs to be shorter than what they would estimate for a regular mitral valve repair. After this, the chordae were tied down

Left atrial appendage exclusion, electro-cautery maze, left atrial plication (in case of giant left atria) were done as required. The incisions were closed, heart deaired, and the patient was weaned off of cardiopulmonary bypass in the conventional manner. Control peroperative post-CPB transesophageal echocardiography confirmed the normal functioning of the valve.

Postoperatively, the authors noted that some of the patients had a transient drop in platelet counts but had a normal thromboelastogram curve, normal bleeding time, and no clinical bleeding. The authors observe these patients and typically the platelet count normalizes by the end of the first week.

The authors believe that this offers a good anticoagulation-free alternative to mechanical valve replacement, especially in young rheumatics and is advantageous to other patients also.

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