Division of Pulmonary and Critical Care Medicine, Department of Medicine, WakeMed Health and Hospitals, 3000 New Bern Ave, Raleigh, NC, USA.
Division of Pulmonary and Critical Care Medicine, Department of Medicine, University of North Carolina, Chapel Hill, USA.
Lung. 2018 Jun;196(3):315-319. doi: 10.1007/s00408-018-0111-0. Epub 2018 Mar 21.
Plasma pro-BNP (brain natriuretic peptide) levels are often elevated in response to right ventricular (RV) volume and pressure overload, parameters potentially affected by exercise. Plasma pro-BNP levels change in association with long-term changes in pulmonary hemodynamics, thereby serving as a potential biomarker in pulmonary arterial hypertension (PAH). The 6-min Walk Test (6MWT) and pro-BNP level are often checked in a single office visit. There is no universal standard for measuring Pro-BNP levels relative to the timing of the 6MWT. Based on the studies in normal subjects indicating that pro-BNP levels changes after exercise, we hypothesized that the pro-BNP might rise after the 6MWT in PAH patients, potentially impacting clinical decisions.
Patients at our center with WHO Group 1 PAH on active therapy at a stable dose for 30 days or more were enrolled. After resting the patient for 30 min, blood was drawn for baseline pro-BNP and a 6MWT was performed. Pro-BNP levels were drawn immediately after the 6MWT and 1 and 2 h later. Pro-BNP was measured using a commercially available ELISA kit. The levels before exercise and after exercise were compared using student's paired t tests.
There were 17 females and 3 male subjects. The mean age was 53 ± 11 years. Seven patients had systemic lupus erythematosus-related PAH, six had idiopathic PAH, three had scleroderma, three had portopulmonary hypertension, and one had HIV-related PAH. The mean PA pressure was 50 ± 15 mmHg with a mean pulmonary vascular resistance of 10 ± 4 Wood units. The majority of the patients were on multimodality PAH therapy, including parenteral prostacyclins. Mean 6MWT distance was 377 ± 140 m. In 14/20 patients, the pro-BNP level increased immediately after the 6MWT; in 12/20 patients, the pro-BNP level was elevated at 1 h post exercise. In the majority of the patients, the pro-BNP fell to baseline 2 h post 6MWT.
There appears to be a trend of pro-BNP level increasing immediately after exercise and continuing to be elevated at 1 h. Pro-BNP levels then return to baseline at 2 h post 6MWT.
血浆脑钠肽前体（brain natriuretic peptide）水平通常会因右心室（RV）容量和压力超负荷而升高，而这些参数可能会受到运动的影响。血浆脑钠肽前体水平的变化与长期肺血流动力学变化相关，因此可作为肺动脉高压（PAH）的潜在生物标志物。6 分钟步行试验（6MWT）和脑钠肽前体水平通常在一次就诊时进行检查。目前尚无将脑钠肽前体水平与 6MWT 时间相关联的通用标准。基于正常受试者的研究表明，运动后脑钠肽前体水平会发生变化，我们假设 PAH 患者在 6MWT 后脑钠肽前体可能会升高，这可能会影响临床决策。
我们招募了在本中心接受治疗且病情稳定的 1 型肺动脉高压患者（WHO 组），他们正在接受稳定剂量的治疗，时间超过 30 天。让患者休息 30 分钟后，抽取血液进行基线脑钠肽前体检测，并进行 6MWT。在 6MWT 后立即、1 小时和 2 小时后抽取脑钠肽前体水平。使用商业上可获得的 ELISA 试剂盒测量脑钠肽前体。使用学生配对 t 检验比较运动前后的水平。
共有 17 名女性和 3 名男性受试者。平均年龄为 53 ± 11 岁。7 名患者为系统性红斑狼疮相关肺动脉高压，6 名患者为特发性肺动脉高压，3 名患者为硬皮病，3 名患者为门脉高压相关肺动脉高压，1 名患者为 HIV 相关肺动脉高压。平均肺动脉压为 50 ± 15mmHg，平均肺血管阻力为 10 ± 4 伍德单位。大多数患者接受多模式肺动脉高压治疗，包括肠外前列腺素。平均 6MWT 距离为 377 ± 140m。在 20 名患者中，有 14 名患者在 6MWT 后即刻脑钠肽前体水平升高；有 12 名患者在运动后 1 小时脑钠肽前体水平升高。在大多数患者中，6MWT 后 2 小时脑钠肽前体水平降至基线。
脑钠肽前体水平似乎有在运动后即刻升高并持续升高至 1 小时的趋势。然后，在 6MWT 后 2 小时，脑钠肽前体水平恢复到基线。
