Bertrand Philippe B, Verbrugge Frederik H, Verhaert David, Smeets Christophe J P, Grieten Lars, Mullens Wilfried, Gutermann Herbert, Dion Robert A, Levine Robert A, Vandervoort Pieter M
Department of Cardiology, Ziekenhuis Oost-Limburg, Genk, Belgium; Faculty of Medicine and Life Sciences, Hasselt University, Diepenbeek, Belgium.
Department of Cardiology, Ziekenhuis Oost-Limburg, Genk, Belgium.
J Am Coll Cardiol. 2015 Feb 10;65(5):452-61. doi: 10.1016/j.jacc.2014.11.037.
Restrictive mitral valve annuloplasty (RMA) for secondary mitral regurgitation might cause functional mitral stenosis, yet its clinical impact and underlying pathophysiological mechanisms remain debated.
The purpose of our study was to assess the hemodynamic and clinical impact of effective orifice area (EOA) after RMA and its relationship with diastolic anterior leaflet (AL) tethering at rest and during exercise.
Consecutive RMA patients (n = 39) underwent a symptom-limited supine bicycle exercise test with Doppler echocardiography and respiratory gas analysis. EOA, transmitral flow rate, mean transmitral gradient, and systolic pulmonary arterial pressure were assessed at different stages of exercise. AL opening angles were measured at rest and peak exercise. Mortality and heart failure readmission data were collected for at least 20 months after surgery.
EOA and AL opening angle were 1.5 ± 0.4 cm(2) and 68 ± 10°, respectively, at rest (r = 0.4; p = 0.014). EOA increased significantly to 2.0 ± 0.5 cm(2) at peak exercise (p < 0.001), showing an improved correlation with AL opening angle (r = 0.6; p < 0.001). Indexed EOA (EOAi) at peak exercise was an independent predictor of exercise capacity (maximal oxygen uptake, p = 0.004) and was independently associated with freedom from all-cause mortality or hospital admission for heart failure (p = 0.034). Patients with exercise EOAi <0.9 cm(2)/m(2) (n = 14) compared with ≥0.9 cm(2)/m(2) (n = 25) had a significantly worse outcome (p = 0.048). In multivariate analysis, AL opening angle at peak exercise (p = 0.037) was the strongest predictor of exercise EOAi.
In RMA patients, EOA increases during exercise despite fixed annular size. Diastolic AL tethering plays a key role in this dynamic process, with increasing AL opening during exercise being associated with higher exercise EOA. EOAi at peak exercise is a strong and independent predictor of exercise capacity and is associated with clinical outcome. Our findings stress the importance of maximizing AL opening by targeting the subvalvular apparatus in future repair algorithms for secondary mitral regurgitation.
用于继发性二尖瓣反流的限制性二尖瓣环成形术（RMA）可能导致功能性二尖瓣狭窄，但其临床影响和潜在的病理生理机制仍存在争议。
我们研究的目的是评估RMA后有效瓣口面积（EOA）的血流动力学和临床影响及其与静息和运动时舒张期前叶（AL）牵拉的关系。
连续的RMA患者（n = 39）接受了症状限制的仰卧位自行车运动试验，同时进行多普勒超声心动图和呼吸气体分析。在运动的不同阶段评估EOA、二尖瓣跨瓣血流速度、平均二尖瓣压差和收缩期肺动脉压。在静息和运动峰值时测量AL开放角度。收集术后至少20个月的死亡率和心力衰竭再入院数据。
静息时EOA和AL开放角度分别为1.5±0.4 cm²和68±10°（r = 0.4；p = 0.014）。运动峰值时EOA显著增加至2.0±0.5 cm²（p < 0.001），与AL开放角度的相关性改善（r = 0.6；p < 0.001）。运动峰值时的标准化EOA（EOAi）是运动能力（最大摄氧量，p = 0.004）的独立预测因素，并且与全因死亡率或心力衰竭住院的无事件生存率独立相关（p = 0.034）。运动EOAi <0.9 cm²/m²的患者（n = 14）与≥0.9 cm²/m²的患者（n = 25）相比，结局明显更差（p = 0.048）。在多变量分析中，运动峰值时的AL开放角度（p = 0.037）是运动EOAi的最强预测因素。
在RMA患者中，尽管瓣环大小固定，但运动期间EOA增加。舒张期AL牵拉在这一动态过程中起关键作用，运动期间AL开放增加与更高的运动EOA相关。运动峰值时的EOAi是运动能力的强大且独立的预测因素，并与临床结局相关。我们的研究结果强调了在未来继发性二尖瓣反流修复算法中通过靶向瓣下装置最大化AL开放的重要性。
