Holverda S, Rietema H, Westerhof N, Marcus J T, Gan C T-J, Postmus P E, Vonk-Noordegraaf A
Department of Pulmonary Diseases, Institute for Cardiovascular Research, VU University Medical Center, Amsterdam, The Netherlands.
Heart. 2009 Feb;95(2):137-41. doi: 10.1136/hrt.2007.138172. Epub 2008 May 12.
This study was designed to investigate the mechanisms by which the right ventricle is able to increase stroke volume (SV) during exercise in chronic obstructive pulmonary disease (COPD). A second aim was to determine whether resting pulmonary artery pressure (Ppa) is predictive of exercise SV.
16 COPD patients (GOLD stages II-IV) underwent right heart catheterisation at rest and during exercise. In this group and eight age-matched controls resting and exercise right ventricular SV, end-diastolic volume (RVEDV) and end-systolic volume (RVESV) were assessed by magnetic resonance imaging (MRI). The exercise protocol during both measurements consisted of 3 minutes of cycling in supine position at 40% of maximal workload.
In all patients mean Ppa increased significantly in response to exercise (21 (8) vs 33 (11) mm Hg, p<0.01), whereas pulmonary vascular resistance did not change. In the patient group, RVEDV (129 (42) vs 135 (42) ml, p<0.05) and SV (63 (13) vs 69 (14) ml, p<0.05) increased significantly from rest to exercise, but RVESV and RV ejection fraction remained unaltered. In contrast, in healthy controls SV is augmented (81 (22) vs 101 (28) ml, p<0.05) by both increased RVEDV (123 (33) vs 134 134) ml, p<0.05) and reduced RVESV (37 (9) vs 27 (10) ml, p<0.05). Resting mean Ppa was related to SV during exercise (r = -0.59, p<0.02).
As a consequence of unaltered pulmonary vascular resistance to exercise in COPD patients, Ppa increases and SV response to exercise is limited and results from an increased preload only. Ppa at rest predicts exercise SV.
本研究旨在探讨慢性阻塞性肺疾病（COPD）患者运动时右心室增加每搏输出量（SV）的机制。第二个目的是确定静息肺动脉压（Ppa）是否可预测运动时的SV。
16例COPD患者（GOLD II-IV级）在静息和运动时接受了右心导管检查。在该组患者以及8名年龄匹配的对照组中，通过磁共振成像（MRI）评估静息和运动时右心室的SV、舒张末期容积（RVEDV）和收缩末期容积（RVESV）。两次测量期间的运动方案均包括在仰卧位以最大负荷的40%进行3分钟的骑行。
所有患者运动时平均Ppa显著升高（21（8）对33（11）mmHg，p<0.01），而肺血管阻力未改变。在患者组中，RVEDV（129（42）对135（42）ml，p<0.05）和SV（63（13）对69（14）ml，p<0.05）从静息到运动时显著增加，但RVESV和右心室射血分数保持不变。相比之下，在健康对照组中，SV通过增加RVEDV（123（33）对134（34）ml，p<0.05）和降低RVESV（37（9）对27（10）ml，p<0.05）而增加（81（22）对101（28）ml，p<0.05）。静息平均Ppa与运动时的SV相关（r = -0.59，p<0.02）。
由于COPD患者运动时肺血管阻力未改变，Ppa升高，运动时SV反应受限且仅由前负荷增加导致。静息时的Ppa可预测运动时的SV。
