Boronyak Steven M, Fredi Joseph L, Young Michael N, Dumont Douglas M, Williams Phillip E, Byram Brett C, Merryman W David
Department of Biomedical Engineering, Vanderbilt University, Room 9445D MRB IV-Langford, 2213 Garland Avenue, Nashville, TN, 37232-0493, USA.
Division of Cardiovascular Medicine, Department of Medicine, Vanderbilt University Medical Center, Nashville, TN, USA.
Ann Biomed Eng. 2016 Jul;44(7):2240-50. doi: 10.1007/s10439-015-1494-1. Epub 2015 Oct 27.
This study reports the initial in vivo use of a combined radiofrequency ablation and cryo-anchoring (RFC) catheter as an alternative to surgical mitral valve (MV) leaflet resection. Radiofrequency ablation thermally shrinks enlarged collagenous tissues, providing an alternative to leaflet resection, and cryo-anchoring provides reversible attachment of a catheter to freely mobile MV leaflets. Excised porcine MVs (n = 9) were tested in a left heart flow simulator to establish treatment efficacy criteria. Resected leaflet area was quantified by tracking markers on the leaflet surface, and leaflet length reductions were directly measured on echocardiography. Leaflet area decreased by 38 ± 2.7%, and leaflet length decreased by 9.2 ± 1.8% following RFC catheter treatment. The RFC catheter was then tested acutely in healthy pigs (n = 5) under epicardial echocardiographic guidance, open-chest without cardiopulmonary bypass, using mid-ventricular free wall access. Leaflet length was quantified using echocardiography. Quantitative assessment of MV leaflet length revealed that leaflet resection was successful in 4 of 5 pigs, with a leaflet length reduction of 13.3 ± 4.6%. Histological, mechanical, and gross pathological findings also confirmed that RFC catheter treatment was efficacious. The RFC catheter significantly reduces MV leaflet size in an acute animal model, providing a possible percutaneous alternative to surgical leaflet resection.
本研究报告了首次在体内使用联合射频消融和冷冻锚定（RFC）导管作为外科二尖瓣（MV）瓣叶切除术的替代方法。射频消融通过热收缩扩大的胶原组织，为瓣叶切除术提供了一种替代方案，而冷冻锚定则使导管能够可逆地附着于可自由移动的MV瓣叶。将切除的猪MV（n = 9）在左心血流模拟器中进行测试，以建立治疗效果标准。通过跟踪瓣叶表面的标记物来量化切除的瓣叶面积，并在超声心动图上直接测量瓣叶长度的减少量。RFC导管治疗后，瓣叶面积减少了38±2.7%，瓣叶长度减少了9.2±1.8%。然后，在健康猪（n = 5）中，在经心外膜超声心动图引导下，采用心室中部游离壁入路，在非体外循环开胸情况下对RFC导管进行急性测试。使用超声心动图对瓣叶长度进行量化。对MV瓣叶长度的定量评估显示，5头猪中有4头的瓣叶切除术成功，瓣叶长度减少了13.3±4.6%。组织学、力学和大体病理学结果也证实RFC导管治疗是有效的。在急性动物模型中，RFC导管可显著减小MV瓣叶大小，为外科瓣叶切除术提供了一种可能的经皮替代方法。
