Beating-heart patch closure of muscular ventricular septal defects under real-time three-dimensional echocardiographic guidance: a preclinical study.

OBJECTIVES: Safe and effective device closure of ventricular septal defects remains a challenge. We have developed a transcardiac approach to close ventricular septal defects using a patch delivery and fixation system that can be secured under real-time three-dimensional echocardiographic guidance.

METHODS: In Yorkshire pigs (n = 8) a coring device was introduced into the left ventricle through a purse-string suture placed on the left ventricular apex, and a muscular ventricular septal defect was created. The patch deployment device containing a 20-mm polyester patch was advanced toward the ventricular septal defect through another purse-string suture on the left ventricular apex, and the patch was deployed under real-time three-dimensional echocardiographic guidance. The anchor delivery device was then introduced into the left ventricle through the first purse-string suture. Nitinol anchors to attach the patch around the ventricular septal defect were deployed under real-time three-dimensional echocardiographic guidance. After patch attachment, residual shunts were sought by means of two-dimensional and three-dimensional color Doppler echocardiography. The heart was then excised, and the septum with the patch was inspected.

RESULTS: A ventricular septal defect was created in the midventricular (n = 4), anterior (n = 2), and apical (n = 2) septum. The mean size was 9.8 mm (8.2-12.0 mm), as determined by means of two-dimensional color Doppler scanning. The ventricular septal defects were completely closed in 7 animals. In one a 2.4-mm residual shunt was identified. No anatomic structures were compromised.

CONCLUSIONS: Beating-heart perventricular muscular ventricular septal defect closure without cardiopulmonary bypass can be successfully achieved by using a catheter-based patch delivery and fixation system under real-time three-dimensional echocardiographic guidance. This approach might be a better alternative to cardiac surgery or transcatheter device closure.