Wallace H. Coulter Department of Biomedical Engineering, Georgia Institute of Technology and Emory University, Suite 200, 387 Technology Circle, Atlanta, GA 30313-2412, USA.
Department of Biomedical Engineering, University of Massachusetts Lowell, Lowell, MA, USA.
Eur Heart J Cardiovasc Imaging. 2022 Apr 18;23(5):650-662. doi: 10.1093/ehjci/jeab074.
To characterize the dynamic nature of the left ventricular outflow tract (LVOT) geometry and flow rate in patients following transcatheter mitral valve replacement (TMVR) with anterior leaflet laceration (LAMPOON) and derive insights to help guide future patient selection.
Time-resolved LVOT geometry and haemodynamics were analysed with post-procedure computed tomography and echocardiography in subjects (N = 19) from the LAMPOON investigational device exemption trial. A novel post hoc definition for LVOT obstruction was employed to account for systolic flow rate and quality of life improvement [obstruction was defined as LVOT gradient >30 mmHg or LVOT effective orifice area (EOA) ≤1.15 cm2]. The neo-LVOT and skirt neo-LVOT were observed to vary substantially in area throughout systole (64 ± 27% and 25 ± 14% change in area, respectively). The peak systolic flow rate occurred most commonly just prior to mid-systole, while minimum neo-LVOT (and skirt neo-LVOT) area occurred most commonly in early-diastole. Subjects with LVOT obstruction (n = 5) had smaller skirt neo-LVOT values across systole. Optimal thresholds for skirt neo-LVOT area were phase-specific (260, 210, 200, and 180 mm2 for early-systole, peak flow, mid-systole, and end-systole, respectively).
The LVOT geometry and flow rate exhibit dynamic characteristics following TMVR with LAMPOON. Subjects with LVOT obstruction had smaller skirt neo-LVOT areas across systole. The authors recommend the use of phase-specific threshold values for skirt neo-LVOT area to guide future patient selection for this procedure. LVOT EOA is a 'flow-independent' metric which has the potential to aid in characterizing LVOT obstruction severity.
通过对经导管二尖瓣置换术（TMVR）后前叶撕裂（LAMPOON）患者的左心室流出道（LVOT）几何形状和流量进行时相分析，描述其动态变化特征，并为指导未来患者选择提供参考依据。
本研究利用术后 CT 和超声心动图对 LAMPOON 器械临床试验（N=19）患者的 LVOT 几何形状和血流动力学进行了时相分析。采用新的术后定义方法来评估 LVOT 阻塞，以评估LVOT 阻塞与收缩期血流速率和生活质量改善之间的关系[LVOT 阻塞定义为 LVOT 梯度>30mmHg 或 LVOT 有效开口面积（EOA）≤1.15cm2]。研究发现，新的 LVOT 和裙边新 LVOT 在整个收缩期的面积变化很大（分别为 64±27%和 25±14%）。收缩期峰值血流速度通常发生在中收缩期之前，而最小的新 LVOT（和裙边新 LVOT）面积通常发生在舒张早期。LVOT 阻塞（n=5）患者的裙边新 LVOT 面积在整个收缩期均较小。裙边新 LVOT 面积的最佳阈值与时相有关（早期收缩期、峰值流量、中期收缩期和晚期收缩期分别为 260、210、200 和 180mm2）。
TMVR 术后 LAMPOON 患者的 LVOT 几何形状和流量呈现动态特征。LVOT 阻塞患者的裙边新 LVOT 面积在整个收缩期均较小。建议使用特定相位的裙边新 LVOT 面积阈值来指导该手术的未来患者选择。LVOT EOA 是一种“流量独立”的指标，有可能帮助评估 LVOT 阻塞的严重程度。
