Kadikar A, Maurer J, Kesten S
Toronto Hospital, University of Toronto, Ontario, Canada.
J Heart Lung Transplant. 1997 Mar;16(3):313-9.
A window of opportunity exists with regard to optimal timing for lung transplantation. Performance of a transplantation too early may rob the patient of months to years of survival, whereas waiting too long increases the risk of death before transplantation. Several studies have examined specific lung function tests as predictors of death, but none have been shown to be useful across the various disorders leading to end-stage lung disease. We therefore sought to examine the usefulness of the 6-minute walk test as a guide to assessment for transplantation.
We conducted a retrospective chart review of patients who were assessed and either were accepted or died waiting acceptance by the Toronto Lung Transplant Program between January 1991 and June 1995. One hundred forty-five patients with the following lung diseases were included: emphysema (n = 38), alpha-1-antitrypsin deficiency (n = 20), idiopathic pulmonary fibrosis (n = 26), primary pulmonary hypertension (n = 10), Eisenmenger's syndrome (n = 9), and cystic fibrosis (n = 41). The sensitivity, specificity, and positive and negative predicted values for a 6-minute walk distance of 300 and 400 m as a predictor of death were calculated.
Mortality rates were as follows: emphysema (7.9%), alpha-1-antitrypsin deficiency (15%), idiopathic pulmonary fibrosis (42.3%), primary pulmonary hypertension (50%), Eisenmenger's syndrome (11%), and cystic fibrosis (24.4%). A 6-minute walk distance of less than 400 m had the following characteristics for prediction of death: sensitivity 0.80, specificity 0.27, positive predictive value 0.27, and negative predictive value 0.91. Similar findings for a 6-minute walk distance of less than 300 m were as follows: 0.52, 0.80, 0.38, and 0.88, respectively.
The 6-minute walk test is a useful tool in the assessment of when to list patients for transplantation. A 6-minute walk test result of less than 400 meters appears to be a reasonable marker with regard to when a patient should be listed for transplantation.
肺移植的最佳时机存在一个机会窗口。移植进行得过早可能会使患者失去数月至数年的生存期，而等待时间过长则会增加移植前死亡的风险。几项研究已对特定的肺功能测试作为死亡预测指标进行了检验，但尚无一项被证明在导致终末期肺病的各种疾病中都有用。因此，我们试图检验6分钟步行试验作为移植评估指南的有用性。
我们对1991年1月至1995年6月期间接受多伦多肺移植项目评估且要么被接受要么在等待接受期间死亡的患者进行了回顾性病历审查。纳入了145例患有以下肺部疾病的患者：肺气肿（n = 38）、α-1抗胰蛋白酶缺乏症（n = 20）、特发性肺纤维化（n = 26）、原发性肺动脉高压（n = 10）、艾森曼格综合征（n = 9）和囊性纤维化（n = 41）。计算了6分钟步行距离为300米和400米作为死亡预测指标的敏感性、特异性以及阳性和阴性预测值。
死亡率如下：肺气肿（7.9%）、α-1抗胰蛋白酶缺乏症（15%）、特发性肺纤维化（42.3%）、原发性肺动脉高压（50%）、艾森曼格综合征（11%）和囊性纤维化（24.4%）。6分钟步行距离小于400米对死亡预测具有以下特征：敏感性0.80、特异性0.27、阳性预测值0.27和阴性预测值0.91。6分钟步行距离小于300米的类似结果分别为：0.52、0.80、0.38和0.88。
6分钟步行试验是评估何时将患者列入移植名单的有用工具。6分钟步行试验结果小于400米似乎是关于患者何时应列入移植名单的一个合理指标。
