BACKGROUND: The clover technique for reducing tricuspid regurgitation (TR) has been shown to provide acceptable long-term outcomes. This technique may be especially useful in microinvasive procedures. This study evaluated a novel procedure for approximating tricuspid leaflets using automated technology for suture placement and securing in an ex vivo porcine heart model.
METHODS: Five porcine hearts with a mean weight of 437.2±21.4 g were attached to a passive beating-heart simulator. Connectors attached to the right atrium and the pulmonary artery were used for in- and outflow of working fluid (0.9% saline solution). Flow was provided by a pulsatile pump (ViVitro Labs Inc., Victoria, BC, Canada), which was coupled to the right ventricle. To induce functional TR, the annulus was mechanically dilated to 43 mm for 10 minutes and the position of the pump cannula was directed towards the tricuspid valve. Stroke volume of the pump was set to 76 mL/stroke. Backflow of working fluid was assessed using ultrasonic transit time measurement (SONOTEC GmbH, Halle, Sachsen-Anhalt, Germany). An automated suturing device (LSI SOLUTIONS, NY, USA) was used to place sutures through the middle of the free edges of the anterior, posterior, and septal leaflets. Sutures were secured in the center of the valve with two automated titanium fasteners (LSI SOLUTIONS, NY, USA). The study's primary endpoint was the regurgitant volume, measured in mL at the inflow site (2-3 cm upstream of the atrial connector).
RESULTS: In the experimental hearts, the mean regurgitant volume after inducing TR was 19.95±5.65 mL. Clover repair was successfully performed in all specimens. Regurgitation was reduced in all samples: mean regurgitant volume decreased to 1.77±2.42 mL (p=0.002). In 2 hearts, TR was completely eliminated.
CONCLUSIONS: This new clover technique procedure was demonstrated to successfully reduce TR in an ex vivo porcine heart model. Automated technology for suture placement and securing offers a promising approach, which may reduce the technical difficulty of performing the clover technique.
LEGEND: A - Quantification of regurgitant volume before and after clover repair.
B - Tricuspid valve with coaptation defect.
C - Repaired tricuspid valve in diastole.
D - Repaired tricuspid valve in systole.
