Department of Cardiology, GIGA Cardiovascular Sciences, Heart Valve Clinic, University of Liège Hospital, CHU Sart Tilman, B - 4000, Liège, Belgium.
Quebec Heart and Lung Institute, Quebec, Canada.
Eur Heart J. 2014 Jun 21;35(24):1608-16. doi: 10.1093/eurheartj/eht345. Epub 2013 Sep 7.
There are very few data regarding the assessment and prognostic value of left ventricular contractile reserve (LVCR) in asymptomatic patients with primary mitral regurgitation (MR). We aimed to quantify LVCR and to evaluate its usefulness for risk stratification in asymptomatic patients with primary MR.
Comprehensive resting and exercise (EX) transthoracic echocardiography, including two-dimensional speckle tracking quantification, were performed in 115 consecutive asymptomatic patients with ≥ moderate degenerative MR and no LV dysfunction/dilatation. Left ventricular contractile reserve was defined as an EX-induced increase in LV ejection fraction (LVCR(LVEF)) ≥ 4% or in LV global longitudinal strain (LVCR(GLS)) ≥ 2%. LVCR(LVEF) was present in 54 patients (47%) and LVCR(GLS) in 58 (50%). The brain natriuretic peptide (BNP) level was significantly correlated with EX-induced changes in GLS (r = 0.45, P < 0.0001), but not in LVEF (r = 0.09, P = 0.31). Patients with no LVCR(GLS) had significant lower 3-year cardiac event-free survival (42 ± 8 vs. 69 ± 7%, P = 0.0008). In contrast, there was no significant difference in outcome regarding to the presence or absence of LVCR(LVEF) (60 ± 7 vs. 51 ± 8%, P = 0.40). The multivariable Cox proportional hazard model showed that the absence of LVCR(GLS) was a strong independent predictor of cardiac events (HR = 2.27, 95% CI: 1.05-4.76, P = 0.037), even after adjustment for Ex-echo variables and BNP level. The association between LVCR(GLS) and outcome remained significant (HR = 1.6, 95% CI: 1.1-2.3, P = 0.01) after further adjustment for the resting echocardiographic parameters included in the ESC Guidelines.
In asymptomatic primary MR, LVCR seems to be better assessed using EX-induced changes in LV myocardial longitudinal function rather than in LVEF. In patients with preserved LV function, the absence of LVCR is independently associated with two-fold increase in risk of cardiac events. Left ventricular contractile reserve may be useful to improve risk stratification and clinical decision-making in these patients.
在无症状的原发性二尖瓣反流（MR）患者中，关于左心室收缩储备（LVCR）的评估和预后价值的数据非常有限。我们旨在量化 LVCR，并评估其在无症状的原发性 MR 患者中的风险分层中的作用。
对 115 例连续的无症状、MR 程度≥中度退行性变且无左心室功能/扩张的患者进行了全面的静息和运动（EX）经胸超声心动图检查，包括二维斑点追踪定量检查。左心室收缩储备定义为 EX 诱导的左心室射血分数增加（LVCR[LVEF]）≥4%或左心室整体纵向应变增加（LVCR[GLS]）≥2%。54 例（47%）患者存在 LVCR[LVEF]，58 例（50%）患者存在 LVCR[GLS]。脑钠肽（BNP）水平与 GLS 的 EX 诱导变化显著相关（r=0.45，P<0.0001），但与 LVEF 无关（r=0.09，P=0.31）。无 LVCR[GLS]的患者 3 年心脏无事件生存率显著降低（42±8%比 69±7%，P=0.0008）。相比之下，LVCR[LVEF]的有无与结局之间无显著差异（60±7%比 51±8%，P=0.40）。多变量 Cox 比例风险模型显示，无 LVCR[GLS]是心脏事件的强独立预测因子（HR=2.27，95%CI：1.05-4.76，P=0.037），即使在调整 EX 超声心动图变量和 BNP 水平后也是如此。LVCR[GLS]与结局之间的关联在进一步调整 ESC 指南中包含的静息超声心动图参数后仍然显著（HR=1.6，95%CI：1.1-2.3，P=0.01）。
在无症状的原发性 MR 患者中，使用 EX 诱导的左心室心肌纵向功能变化而不是 LVEF 评估 LVCR 似乎更好。在保留左心室功能的患者中，LVCR 的缺失与心脏事件风险增加两倍独立相关。LVCR 可能有助于改善这些患者的风险分层和临床决策。
