Performance and healing of an expanded polytetrafluoroethylene multichordal device at 6 months after repair of mitral leaflet flail in swine.

OBJECTIVE

Repairing a prolapsed mitral valve that involves multiple cusps is procedurally complicated and carries a higher risk of failure when performed with individual neochordae. Inserting multiple neochordae into the papillary muscle, sizing, and aligning them in a manner that can restore coaptation is challenging. A multichordal mitral valve apparatus (MitraPatch) with a single neopapillary muscle section, 4 neochordae with each chord ending in a neoleaflet section, was developed. In this study, the 6-month outcomes of using this apparatus to repair mitral prolapse in swine is reported.

METHODS

Seven pigs (n = 7) with prolapse from mitral chordal transection were repaired with the device. One pig was used to develop the procedure, and 6 swine received the implant and were survived to 150 days (n = 4) and 180 days (n = 2), with monthly echocardiographic examinations. All hearts were explanted for gross necropsy and detailed histopathology.

RESULTS

Severe mitral regurgitation (MR) was observed after chordal transection in all pigs. Repairing the valve with the device reduced MR to none-or-trace levels in 3 swine, grade 1 in 3 swine, and 1 to 2+ in 1 swine immediately after surgery. In the pigs with none/trace/grade 1 MR, the device was intact and coaptation was fully restored as observed on serial echocardiograms. The device was intact, without dehiscence, stretching, or fibrosis at termination. The neoleaflet and neopapillary sections of the device elicited a host response, which is on track to produce living valve replacement tissue, but we cannot tell how controlled this might be several years later. In the pig with grade 1 to 2+ MR, accidental transection of both marginal and strut chordae in that region was observed at death, with dehiscence of the device at the site of its insertion into the leaflet.

CONCLUSIONS

The anatomic principles that guide this multichordal design appear to be valid, with good hemodynamic performance and a controlled host response at 6 months.