Department of Cardiology, Rigshospitalet, Copenhagen, Denmark.
Baker IDI Heart and Diabetes Research Institute, Melbourne, Australia.
Eur J Heart Fail. 2018 Apr;20(4):715-722. doi: 10.1002/ejhf.976. Epub 2017 Sep 26.
Patients with heart failure and preserved ejection fraction (HFpEF) are characterized by functional impairment and an abnormal haemodynamic response to exercise. The six-minute walk test (6MWT) serves as a standardized test for functional capacity quantification in heart failure patients, and is associated with cardiovascular outcomes. However, as the association between 6MWT and haemodynamic parameters during rest and exercise in HFpEF patients is unknown, we sought to elucidate this relationship.
Overall, 64 patients enrolled in the REDUCE LAP-HF trial completed a 6MWT at baseline. Univariate and multivariable linear regression models were used to assess the associations between 6MWT and measured or derived haemodynamic variables at baseline, during light/moderate exercise (20 W), and at peak supine exercise. The average 6MWT distance was 318 ± 106 m. At rest, in a multivariable model, only pulmonary capillary wedge pressure (PCWP) was significantly associated with 6MWT [coefficient: -5.4, 95% confidence interval (CI) -10.4, -0.5, P = 0.033]. During light/moderate exercise, mean pulmonary artery pressure was associated with 6MWT in a multivariable model (coefficient: -3.5, 95% CI -6.8, -0.3, P = 0.033). During peak exercise, central venous pressure, cardiac index (CI), and PCWP/CI correlated with 6MWT; however, workload corrected PCWP was the only variable independently associated with 6MWT (coefficient: -0.8, 95% CI -1.3, -0.4, P < 0.001). The variance in 6MWT was modestly explained by measured or derived haemodynamic variables at rest or at any stage of exercise (r = 7-17%).
Workload corrected PCWP correlated best with 6MWT performance in HFpEF patients. Baseline haemodynamic variables were modestly correlated with 6MWT, suggesting that 6MWT performance in HFpEF patients may be significantly influenced by extra-cardiac factors.
射血分数保留的心力衰竭(HFpEF)患者的特点是功能障碍和对运动的异常血液动力学反应。六分钟步行试验(6MWT)是心力衰竭患者功能能力量化的标准化测试,与心血管结局相关。然而,由于 HFpEF 患者在静息和运动期间 6MWT 与血液动力学参数之间的关系尚不清楚,我们试图阐明这种关系。
总体而言,参加 REDUCE LAP-HF 试验的 64 名患者在基线时完成了 6MWT。使用单变量和多变量线性回归模型来评估 6MWT 与基线时、轻度/中度运动期间(20 W)和仰卧位运动峰值时测量或推导的血液动力学变量之间的关系。平均 6MWT 距离为 318±106m。在静息状态下,在多变量模型中,只有肺毛细血管楔压(PCWP)与 6MWT 显著相关[系数:-5.4,95%置信区间(CI)-10.4,-0.5,P=0.033]。在轻度/中度运动期间,平均肺动脉压在多变量模型中与 6MWT 相关(系数:-3.5,95%CI-6.8,-0.3,P=0.033)。在运动峰值时,中心静脉压、心指数(CI)和 PCWP/CI 与 6MWT 相关;然而,校正后工作负荷的 PCWP 是唯一与 6MWT 独立相关的变量(系数:-0.8,95%CI-1.3,-0.4,P<0.001)。静息或任何运动阶段的测量或推导的血液动力学变量可以适度解释 6MWT 的变化(r=7-17%)。
校正后工作负荷的 PCWP 与 HFpEF 患者的 6MWT 表现相关性最好。基线血液动力学变量与 6MWT 有适度相关性,表明 HFpEF 患者的 6MWT 表现可能受到心脏外因素的显著影响。