Active mitral ring for post-surgical remote correction of residual mitral regurgitation on the beating heart

作者：Tozzi Piergiorgio^*; Locca Didier; Gronchi Fabrizio; Hayoz Daniel; Ferrari Enrico; von Segesser Ludwig K; Hullin Roger

来源：European Journal of Cardio-Thoracic Surgery, 2013, 44(2): 370-374.

DOI：10.1093/ejcts/ezs710

• Mitral regurgitation
• Mitral valve repair
• Valvuloplasty
• Echocardiography

OBJECTIVES: Residual mitral regurgitation after valve repair worsens patients' clinical outcome. Postimplant adjustable mitral rings potentially address this issue, allowing the reshaping of the annulus on the beating heart under echocardiography control. We developed an original mitral ring allowing valve geometry remodelling after the implantation and designed an animal study to assess device effectiveness in correcting residual mitral regurgitation.
METHODS: The device consists of two concentric rings: one internal and flexible, sutured to the mitral annulus and a second external and rigid. A third conic element slides between the two rings, modifying the shape of the flexible ring. This sliding element is remotely activated with a rotating tool. Animal model: in adult swine, under cardio pulmonary bypass and cardiac arrest, we shortened the primary chordae of P2 segment to reproduce Type III regurgitation and implanted the active ring. We used intracardiac ultrasound to assess mitral regurgitation and the efficacy of the active ring to correct it.
RESULTS: Severe mitral regurgitation (3+ and 4+) was induced in eight animals, 54 +/- 6 kg in weight. Vena contracta width decreased from 0.8 +/- 0.2 to 0.1 cm; proximal isovelocity surface area radius decreased from 0.8 +/- 0.2 to 0.1 cm and effective regurgitant orifice area decreased from 0.50 +/- 0.1 to 0.1 +/- 0.1 cm(2). Six animals had a reversal of systolic pulmonary flow that normalized following the activation of the device. All corrections were reversible.
CONCLUSIONS: Postimplant adjustable mitral ring corrects severe mitral regurgitation through the reversible modification of the annulus geometry on the beating heart. It addresses the frequent and morbid issue of recurrent mitral valve regurgitation.

• 出版日期2013-8