In vivo performance of a tri-leaflet mechanical heart valve prosthesis in an ovine model

OBJECTIVES: We present the long-term results of a trileaflet (Triflo) versus bileaflet (On-X) mechanical valve in both aortic and pulmonary positions in a sheep model. METHODS: The Triflo valve was implanted in 21 female sheep in aortic (n = 8) and pulmonary position ( n = 13). The On-X valve was implanted in 7 female sheep in aortic (n = 1) and pulmonary (n = 6) positions. No antithrombotic medication of any kind was given postoperatively. In the aortic group, survival cohorts were 3 and 5 months. In the pulmonary group, survival cohorts were 10 and 20 weeks. Valve performance was assessed using haematology, echocardiography and acoustic measurements combined with post-mortem pathology analysis of the downstream organs. RESULTS: The mean gradients were lower for the Triflo valve in both pulmonary [4.30mmHg (3.70-5.73) vs 6.80mmHg (4.63-7.96), P = 0.012] and aortic [5.1mmHg (4.2-7.7) vs 10.7mmHg (8.7-12.9), P = 0.007] positions. Peak gradients were lower for the Triflo valve in both pulmonary [8.05mmHg (6.75-10.23) vs 13.15mmHg (9.20-14.76), P = 0.005] and aortic [8.7mmHg (7.5-12.5) vs 16.5mmHg (14.2-19.6), P = 0.009] positions. In both positions, leaflets and housing surface were free from any deposits macro- and microscopically and comparable to nonimplanted control valves. Peripheral organs showed no signs of thrombo-embolic damage. Biochemical and haematological were comparable to preoperative. The closing click sound pressure level of the Triflo was significantly lower in both aortic [108.4 sound pressure level (102.0-115.7) vs 111.7 sound pressure level (105.5-117.0), P < 0.001] and pulmonary [103.6 sound pressure level (99.1-108.9) vs 118.5 sound pressure level (116.7-120.2), P < 0.001] position. CONCLUSIONS: Preliminary in vivo results of the Triflo valve are promising in both aortic and pulmonary positions in an ovine model. Excellent haemodynamics, stable long-term function, low valve noise and no thrombo-embolic events in the absence of antithrombotic medication lay the foundation to a future clinical first-in-man trial.

Automated summary

This study presents the long-term results of Triflo versus On-X mechanical valves in both aortic and pulmonary positions in a sheep model. The Triflo valve showed lower mean and peak gradients, excellent hemodynamics, stable long-term function, and low valve noise. These results lay the foundation for future clinical trials.