Division of Cardiology, University of Ottawa Heart Institute, University of Ottawa, Ottawa, Ontario, Canada.
Division of Cardiac Surgery, University of Ottawa Heart Institute, University of Ottawa, Ottawa, Ontario, Canada.
PLoS One. 2018 Apr 26;13(4):e0195641. doi: 10.1371/journal.pone.0195641. eCollection 2018.
Transcatheter aortic valve replacement (TAVR) reduces left ventricular (LV) afterload and improves prognosis in aortic stenosis (AS) patients. However, LV afterload consists of both valvular and arterial loads, and the benefits of TAVR may be attenuated if the arterial load dominates. We proposed a new hemodynamic index, the Relative Valve Load (RVL), a ratio of mean gradient (MG) and valvuloarterial impedance (Zva), to describe the relative contribution of the valvular load to the global LV load, and examined whether RVL predicted patient outcome following TAVR.
A total of 258 patients with symptomatic severe AS (indexed aortic valve area (AVA)<0.6cm2/m2, AR≤2+) underwent successful TAVR at the University of Ottawa Heart Institute and had clinical follow-up to 1-year post-TAVR. Pre-TAVR MG, AVA, percent stroke work loss (%SWL), Zva and RVL were measured by echocardiography. The primary endpoint was all cause mortality at 1-year post TAVR.
There were 53 deaths (20.5%) at 1-year. RVL≤7.95ml/m2 had a sensitivity of 60.4% and specificity of 75.1% for identifying all cause mortality at 1-year post-TAVR and provided better specificity than MG<40 mmHg, AVA>0.75cm2, %SWL≤25% and Zva>5mmHg/ml/m2 despite equivalent or better sensitivity. In multivariable Cox analysis, RVL≤7.95ml/m2 was an independent predictor of all cause mortality (HR 3.2, CI 1.8-5.9; p<0.0001). RVL≤7.95ml/m2 was predictive of all cause mortality in both low flow and normal flow severe AS.
RVL is a strong predictor of all-cause mortality in severe AS patients undergoing TAVR. A pre-procedural RVL≤7.95ml/m2 identifies AS patients at increased risk of death despite TAVR and may assist with decision making on the benefits of TAVR.
经导管主动脉瓣置换术（TAVR）可降低主动脉瓣狭窄（AS）患者的左心室（LV）后负荷并改善预后。然而，LV 后负荷包括瓣膜负荷和动脉负荷，如果动脉负荷占主导地位，TAVR 的益处可能会减弱。我们提出了一种新的血流动力学指数，即相对瓣膜负荷（RVL），它是平均梯度（MG）与瓣膜-动脉阻抗（Zva）的比值，用于描述瓣膜负荷对整体 LV 负荷的相对贡献，并探讨 RVL 是否可以预测 TAVR 后患者的预后。
共有 258 名症状性严重 AS 患者（指数化主动脉瓣口面积（AVA）<0.6cm2/m2，AR≤2+）在渥太华大学心脏研究所成功接受 TAVR 治疗，并在 TAVR 后 1 年进行临床随访。术前通过超声心动图测量 MG、AVA、卒中功损失百分比（%SWL）、Zva 和 RVL。主要终点是 TAVR 后 1 年的全因死亡率。
1 年内有 53 例死亡（20.5%）。RVL≤7.95ml/m2 对 TAVR 后 1 年全因死亡的敏感性为 60.4%，特异性为 75.1%，特异性优于 MG<40mmHg、AVA>0.75cm2、%SWL≤25%和 Zva>5mmHg/ml/m2，尽管敏感性相当或更好。多变量 Cox 分析显示，RVL≤7.95ml/m2 是全因死亡的独立预测因素（HR 3.2，95%CI 1.8-5.9；p<0.0001）。RVL≤7.95ml/m2 在低流量和正常流量严重 AS 患者中均能预测全因死亡率。
RVL 是 TAVR 治疗严重 AS 患者全因死亡率的有力预测指标。术前 RVL≤7.95ml/m2 可识别出 TAVR 后死亡风险增加的 AS 患者，可能有助于决策 TAVR 的获益。
