Van Nooten Guido J, Taeymans Yves, Van Belleghem Yves, François Katrien, Van Overbeke Hans, Poelaert Jan, Caes Frank, De Pauw Michel
Heart Centre, University Hospital, Ghent, Belgium.
Heart Lung Circ. 2003;12(3):164-71. doi: 10.1046/j.1444-2892.2003.00205.x.
The design of the bileaflet ATS (ATS Medical Inc., Minneapolis, USA) mechanical valve incorporates an open pivot at the hinge mechanism. Total washout of the blood at the pivot area was observed using 3-D computational fluid dynamics modelling. This phenomenon could make the valve less vulnerable to clot formation in patients without major thromboembolic risk factors.
From January 1993 to June 1999, 286 consecutive patients had the ATS valve inserted in the aortic position. Patients were divided into two groups. Group 1 comprised all patients in regular sinus rhythm with good left ventricular function (144 patients). Group 2 included patients in non-sinus rhythm and/or with large hypocontractile left ventricles (142 patients). The anticoagulation regime in group 1 was used to obtain an international normalised ratio (INR) between 1.5 and 2.5. This contrasts with our regular aim to maintain the INR strictly between 2.5 and 3.5 for all mechanical valves, as achieved in group 2.
The follow-up period (99% completeness) ranged from 18 to 84 months. Survival (Kaplan-Meier) was 97 and 98% and 92 and 81% at 1 and 5 years in group 1 and group 2, respectively (P = 0.12). Log rank analysis failed to detect a statistical difference in thromboembolism or bleeding between both groups (P > 0.05). However, trends were in favour of group 1. Univariate analysis selected poor ventricular function and an 'erratic' INR value (P = 0.002) as risk factors for death. The sole independent risk factor for bleeding was the use of aspirin (P = 0.025).
The excellent group 1 data and outcome encouraged us to continue our low intensive anticoagulation regime and perhaps should be regarded as a new concept for treatment of selected mechanical valve patients.
双叶ATS（美国明尼阿波利斯市ATS医疗公司）机械瓣膜的设计在铰链机制处采用了开放式枢轴。通过三维计算流体动力学建模观察到枢轴区域血液的完全冲洗。这种现象可能使该瓣膜在没有主要血栓栓塞风险因素的患者中不易形成血栓。
1993年1月至1999年6月，286例连续患者在主动脉位置植入了ATS瓣膜。患者分为两组。第1组包括所有窦性心律正常且左心室功能良好的患者（144例）。第2组包括非窦性心律和/或左心室收缩功能严重减退的患者（142例）。第1组的抗凝方案是使国际标准化比值（INR）维持在1.5至2.5之间。这与我们通常对所有机械瓣膜将INR严格维持在2.5至3.5之间的目标形成对比，第2组就是这样实现的。
随访期（99%完整）为18至84个月。第1组和第2组在1年和5年时的生存率（Kaplan-Meier法）分别为97%和98%以及92%和81%（P = 0.12）。对数秩分析未发现两组之间在血栓栓塞或出血方面存在统计学差异（P > 0.05）。然而，趋势有利于第1组。单因素分析选择心室功能差和INR值“不稳定”（P = 0.002）作为死亡的风险因素。出血的唯一独立风险因素是使用阿司匹林（P = 0.025）。
第1组出色的数据和结果鼓励我们继续采用低强度抗凝方案，也许应将其视为治疗特定机械瓣膜患者的新概念。
