Department of Respiratory Medicine, National Hospital Organization, Ibarakihigashi National Hospital, 825, Terunuma. Tokai-mura, Naka-gun, Ibaraki, 319-1113, Japan.
BMC Pulm Med. 2019 Sep 2;19(1):167. doi: 10.1186/s12890-019-0932-5.
Pulmonary hypertension (PH) is traditionally defined as a resting mean pulmonary artery pressure (mPAP) of ≥25 mmHg, while mPAP in the range of 21 to 24 mmHg is recognized as "borderline PH." Interstitial lung disease (ILD) is complicated by the development of PH, which is known to be linked with exercise intolerance and a poor prognosis. Even though it has recently been recommended that PH is redefined as a mPAP of > 20 mmHg, little is known about the clinical significance of borderline PH in ILD. We evaluated whether borderline PH has an impact on the exercise capacity, risk of acute exacerbation (AE), and mortality in patients with ILD.
A total of 80 patients with ILD who underwent right heart catheterization (RHC) between November 2013 and October 2016 were included. The patients were divided into 3 groups according to the mPAP values: mPAP ≤20 mmHg (No-PH group; n = 56), 20 < mPAP < 25 mmHg (Bo-PH group; n = 18), and mPAP ≥25 mmHg (PH group; n = 6). The demographic, hemodynamic, spirometric, and 6-min walk test (6MWT) data of the patients were collected. In addition, the 1-year incidence of AEs and 1-year survival of the patients after the initial RHC were also evaluated.
There were no significant differences among the 3 groups in the mean age, pulmonary function parameters or the PaO, however, 6-min walk distance was significantly lower in both the Bo-PH and PH groups (p < 0.001 for both) as compared to the No-PH group. The results of the Kaplan-Meier analysis revealed that while there was no significant difference in the 1-year survival rate among the three groups, the 1-year incidence of AEs was significantly higher in both the Bo-PH and PH groups (p < 0.001, p = 0.023, respectively) as compared to the No-PH group.
The current study suggested that borderline PH may be associated with poorer exercise tolerance and an increased risk of AEs in patients with ILD. Therefore, the physicians should pay close attention to the presence of even mild elevation of the mPAP at the initial evaluation in patients with ILD.
肺动脉高压（PH）传统上定义为静息平均肺动脉压（mPAP）≥25mmHg，而 mPAP 在 21 至 24mmHg 范围内被认为是“临界 PH”。间质性肺疾病（ILD）并发 PH，已知 PH 与运动耐量下降和预后不良有关。尽管最近有人建议将 PH 重新定义为 mPAP>20mmHg，但对于 ILD 中的临界 PH 的临床意义知之甚少。我们评估了临界 PH 是否对 ILD 患者的运动能力、急性加重（AE）风险和死亡率有影响。
共纳入 2013 年 11 月至 2016 年 10 月间接受右心导管检查（RHC）的 80 例 ILD 患者。根据 mPAP 值将患者分为 3 组：mPAP≤20mmHg（无 PH 组；n=56）、20<mPAP<25mmHg（临界 PH 组；n=18）和 mPAP≥25mmHg（PH 组；n=6）。收集患者的人口统计学、血流动力学、肺功能和 6 分钟步行试验（6MWT）数据。此外，还评估了患者初始 RHC 后 1 年 AE 的发生率和 1 年生存率。
3 组患者的平均年龄、肺功能参数或 PaO 无显著差异，但与无 PH 组相比，临界 PH 和 PH 组的 6 分钟步行距离明显较低（均 p<0.001）。Kaplan-Meier 分析结果显示，3 组患者的 1 年生存率无显著差异，但临界 PH 和 PH 组的 1 年 AE 发生率明显高于无 PH 组（均 p<0.001，p=0.023）。
本研究表明，临界 PH 可能与 ILD 患者运动耐量下降和 AE 风险增加有关。因此，医生在对 ILD 患者进行初始评估时，应密切关注 mPAP 即使轻度升高。
