Sutureless robot-assisted mitral valve repair: an animal model

Robotic mitral valve repair with the da Vinci robotic surgical system has been performed in more than 70 patients at our institution. This procedure reduces the need for blood transfusions, shortens hospital stay, and hastens return to normal activities. However, the robot-assisted repair also requires longer cardiopulmonary bypass and arrested-heart times than conventional open repairs. Because of increased risk of myocardial damage, arrhythmia, and other significant morbidities associated with longer arrested-heart time, a more efficient tissue approximation and adherence technique was evaluated to reduce operating time.

Twelve Dorset sheep were divided equally into 2 groups. In the control group Cosgrove-Edwards annuloplasty bands were secured to the posterior annulus with conventional 2-0 Ticron mattress sutures placed with robotic assistance. In the experimental group, the band was secured with double-armed nitinol U-clips placed with robotic assistance. Postoperative echocardiography was used to assess mitral valve function, and the animals were sacrificed at 3 or 6 months for histological evaluation.

Total U-clip placement time was significantly decreased at 2.6 +/- 0.2 (mean +/- SEM) minutes versus total suture placement time at 4.9 +/- 0.4 minutes (P =.001). The main difference in time occurred between clip deployment at 0.75 +/- 0.1 minutes and suture tying at 2.78 +/- 0.2 minutes (P =.000003). Pathologic review showed excellent band incorporation at 3 and 6 months. Echocardiographic imaging showed no discernible mitral valve stenosis or regurgitation.

With more cardiac procedures progressing toward minimally invasive approaches, novel technology to improve existing techniques must be evaluated. Nitinol U-clips help to reduce arrested-heart time and may improve outcome by decreasing morbidity. U-clip placement is intuitive, easily learned, and effective in securing the annuloplasty band to the mitral annulus.