Zugck C, Krüger C, Dürr S, Gerber S H, Haunstetter A, Hornig K, Kübler W, Haass M
Department of Cardiology, University of Heidelberg, Germany.
Eur Heart J. 2000 Apr;21(7):540-9. doi: 10.1053/euhj.1999.1861.
The 6-min walk test may serve as a more simple clinical tool to assess functional capacity in congestive heart failure than determination of peak oxygen uptake by cardiopulmonary exercise testing. The purpose of the study was to prospectively examine whether the distance ambulated during a 6-min walk test (i) correlates with peak oxygen uptake, (ii) allows peak oxygen uptake to be predicted, and (iii) provides prognostic information similar to peak oxygen uptake in patients with dilated cardiomyopathy and left ventricular ejection fraction < or = 35%.
In 113 patients (age: 54+/-12 years, NYHA: 2.2+/-0.8) with dilated cardiomyopathy (left ventricular ejection fraction 19+/-7%) a 6-min walk test and cardiopulmonary exercise testing were performed. The 6-min walk test and peak oxygen uptake were closely correlated at the initial visit (r=0.68, n=113), as well as after 263+/-114 (r=0.71, n=28) and 381+/-170 days (r=0.74, n=14). During serial exercise testing the 6-min walk test allowed peak oxygen uptake to be reliably predicted (r=0.76 between calculated and real peak oxygen uptake). After 528+/-234 days, 42 patients were hospitalized due to worsening heart failure and/or died from cardiovascular causes. Compared to clinically stable patients, these 42 patients walked a shorter distance (423+/-104 vs 501+/-95 m, P<0.001) and had a lower peak oxygen uptake (12.7+/-4.0 vs 17.4 + 5.6 ml x min(-1) x kg(-1), P<0.001). By univariate analysis the 6-min walk test outperformed other prognostic parameters such as left ventricular ejection fraction, cardiac index and plasma norepinephrine concentration and conferred a prognostic power similar to peak oxygen uptake. This predictive value could be further improved in a multivariate model, by combining the 6-min walk test with independent variables, such as left ventricular ejection fraction or cardiac index.
The 6-min walk test correlated with peak oxygen uptake when tested serially over the course of the disease. Although both tests define two distinct domains of functional capacity, the 6-min walk test provides prognostic information very similar to peak oxygen uptake in congestive heart failure patients with dilated cardiomyopathy.
与通过心肺运动试验测定峰值摄氧量相比，6分钟步行试验可能是评估充血性心力衰竭患者功能能力的一种更简单的临床工具。本研究的目的是前瞻性地研究6分钟步行试验期间行走的距离是否：（i）与峰值摄氧量相关；（ii）能够预测峰值摄氧量；（iii）在扩张型心肌病且左心室射血分数≤35%的患者中提供与峰值摄氧量相似的预后信息。
对113例扩张型心肌病患者（年龄：54±12岁，纽约心脏协会心功能分级：2.2±0.8）进行了6分钟步行试验和心肺运动试验，这些患者的左心室射血分数为19±7%。在初次就诊时，6分钟步行试验与峰值摄氧量密切相关（r = 0.68，n = 113），在263±114天（r = 0.71，n = 28）和381±170天（r = 0.74，n = 14）后同样密切相关。在系列运动试验中，6分钟步行试验能够可靠地预测峰值摄氧量（计算所得的峰值摄氧量与实际峰值摄氧量之间的r = 0.76）。在528±234天后，42例患者因心力衰竭恶化住院和/或死于心血管原因。与临床稳定的患者相比，这42例患者行走的距离较短（423±104 vs 501±95米，P < 0.001），峰值摄氧量较低（12.7±4.0 vs 17.4 + 5.6毫升·分钟⁻¹·千克⁻¹，P < 0.001）。单因素分析显示，6分钟步行试验优于其他预后参数，如左心室射血分数、心脏指数和血浆去甲肾上腺素浓度，其预后能力与峰值摄氧量相似。通过将6分钟步行试验与左心室射血分数或心脏指数等自变量相结合，在多变量模型中可进一步提高这种预测价值。
在疾病过程中进行系列检测时，6分钟步行试验与峰值摄氧量相关。虽然这两种检测方法定义了两个不同的功能能力领域，但6分钟步行试验在扩张型心肌病充血性心力衰竭患者中提供的预后信息与峰值摄氧量非常相似。
