Abstract 14206: Right Ventricle Anterior Papillary Muscle Approximation Toward Septum Reduces Functional Tricuspid Regurgitation and Improves Annular and Ventricular Dimensions in a Swine Model
Functional tricuspid regurgitation (TR) is typically repaired by annuloplasty, but long term results are imperfect due to leaflet tethering from dislocated papillary muscles. Also, use of a prosthetic ring for annuloplasty in growing children is a limitation. We have developed an alternative technique with right ventricular papillary muscle approximation (RV-PMA) and assessed its effectiveness to treat functional TR. Swine (n=5, 50.8±2.1 kg), at 4-5 weeks after beating-heart TR creation by annular incisions using the cardioport video-assisted imaging system through right thoracotomy, underwent RV-PMA on cardiopulmonary bypass via midsternal incision by approximating the anterior PM of RV and ventricular septum with sutures, followed by euthanasia after 4 weeks. Color-Doppler and three-dimensional epicardial echocardiography were obtained before TR creation, before and after RV-PMA, and at euthanasia. TR volume per beat was calculated from effective regurgitant orifice area (flow convergence method) and velocity-time integral of TR. As a result, RV-PMA reduced TR grade from moderate-severe to mild. TR volume, vena contracta area of tricuspid valve, septal-lateral diameter and area of tricuspid annulus, tricuspid valve tethering height and RV sphericity index decreased after RV-PMA. There was no suture detachment or tricuspid stenosis. The effects of RV-PMA remained after 4 weeks although tricuspid annulus was slightly dilated. In conclusion, RV-PMA alleviates functional TR by reducing both tricuspid annular dimension and valve tethering in a chronic TR model. This technique can replace tricuspid annuloplasty to treat TR, especially in growing children.
- © 2011 by American Heart Association, Inc.