Yun K L, Sintek C F, Fletcher A D, Pfeffer T A, Kochamba G S, Hyde M R, Torpoco J O, Khonsari S
Department of Cardiac Surgery, Kaiser Permanente Medical Center, Los Angeles, CA 90027, USA.
Circulation. 1999 Nov 9;100(19 Suppl):II17-23. doi: 10.1161/01.cir.100.suppl_2.ii-17.
Stentless aortic valves were designed to provide a more physiological flow pattern and lower transvalvular gradient, which may have an important bearing on postoperative left ventricular function and remodeling. In this study, we prospectively analyzed the 5-year clinical results with the Freestyle valve (Medtronic, Inc) and its hemodynamic performance by serial echocardiography.
Between January 1993 and August 1997, 95 patients with a mean age of 75 years underwent aortic valve replacement with the Freestyle prosthesis. Sixty-four percent of patients received valves </=23 mm, and 37% had concomitant coronary artery bypass grafting. Average follow-up was 44+/-18 months (mean+/-SD), and echocardiography was performed preoperatively, at discharge, at 3 to 6 months, and annually thereafter. The 30-day operative mortality rate was 3%, with an overall actuarial survival rate of 80+/-6% (mean+/-SEM) at 5 years. Of the 10 late deaths, only 2 were cardiac related, thereby yielding a freedom from cardiac mortality of 94+/-3% after 5 years. No patient required reoperation on the aortic valve for any reason, including structural degeneration, nonstructural dysfunction, or prosthetic valve endocarditis. There were 9 thromboembolic and 3 anticoagulant-related bleeding events, none of which was fatal. The actuarial freedom from valve-related morbidity and mortality was 79+/-4% at 5 years. Hemodynamically, the mean transvalvular gradient significantly decreased after valve replacement and was reduced further by 41% by 6 months with a corresponding increase in effective orifice area. Left ventricular mass index fell to 75% of the preoperative value by 2 years.
The Freestyle stentless valve can be implanted safely in the elderly with excellent midterm clinical results. It has superb hemodynamics in terms of residual transvalvular gradient, effective orifice area, and regression of left ventricular hypertrophy.
无支架主动脉瓣旨在提供更符合生理的血流模式和更低的跨瓣压差，这可能对术后左心室功能和重塑具有重要影响。在本研究中，我们通过系列超声心动图前瞻性分析了Freestyle瓣膜（美敦力公司）的5年临床结果及其血流动力学性能。
1993年1月至1997年8月，95例平均年龄75岁的患者接受了Freestyle人工瓣膜主动脉瓣置换术。64%的患者接受的瓣膜尺寸≤23 mm，37%的患者同时进行了冠状动脉旁路移植术。平均随访时间为44±18个月（均值±标准差），术前、出院时、3至6个月时以及此后每年进行超声心动图检查。30天手术死亡率为3%，5年时总体精算生存率为80±6%（均值±标准误）。10例晚期死亡中，仅2例与心脏相关，因此5年后心脏死亡率的自由度为94±3%。没有患者因任何原因需要对主动脉瓣进行再次手术，包括结构退变、非结构功能障碍或人工瓣膜心内膜炎。有9例血栓栓塞事件和3例抗凝相关出血事件，均无致命性。5年时与瓣膜相关的发病率和死亡率的精算自由度为79±4%。在血流动力学方面，瓣膜置换术后平均跨瓣压差显著降低，6个月时进一步降低41%，有效瓣口面积相应增加。左心室质量指数在2年时降至术前值的75%。
Freestyle无支架瓣膜可安全植入老年患者，中期临床结果良好。在残余跨瓣压差、有效瓣口面积和左心室肥厚消退方面具有出色的血流动力学表现。
