慢性閉塞性肺疾患における肺動脈コンプライアンスの推定

Estimation of Pulmonary Arterial Compliance in Chronic Obstructive Pulmonary Disease

　慢性閉塞性肺疾患患者26名に右心カテーテル検査を施行し，安静時と酸素吸入時の血漿ノルアドレナリン濃度と肺循環諸量を求めた．対象26名を，％FEV_1.0≦55のL群（n＝12）と，55＜％FEV_1.0≦70のH群（n＝14）に大別して比較検討したL群の安静時血漿ノルアドレナリン濃度はH群に比して有意に高く，酸素吸入後，有意に減少した．また，安静時平均肺動脈圧は，両群間で有意差を認めなかったが，両群とも酸素吸入後に有意に減少した．肺血管抵抗係数と肺動脈コンプライアンスは両群で有意差を認めなかったが，H群では酸素吸入後に肺動脈コンプライアンスの上昇を認めた．軽度の閉塞性肺疾患においては，酸素吸入により肺動脈コンプライアンスは改善するが，高度の閉塞性肺疾患では酸素吸入による血漿ノルアドレナリン濃度の減少と平均肺動脈圧の低下が認められるものの，肺動脈コンプライアンスは改善せず，この原因として肺血管のremodelingの進行が推測された．

In 26 patients with chronic obstructive pulmonary disease (COPD), mean pulmonary arterial pressure (mPA) and pulmonary vascular resistance index (PVRI) were measured at rest and during oxygen inha-lation by right cardiac catheterization. Plasma nora-drenaline (NA) concentration was measured simultane-ously. Pulmonary arterial compliance (Cp) was esti-mated from the pulmonary arterial pressure curve by Levenson' s method. 26 patients were divided into two groups; Group L (%FEV_1.0≦55, n=12) and Group H (55＜%_1.0≦70, n=14). Plasma NA level in group L was higher than that in group H (p＜0.05) at rest and decreased during oxygen inhalation significantly (p＜ 0.05). While no significant difference was seen in mPA, PVRI and Cp at rest in both groups, mPA in both groups decreased (p＜0.01) and Cp in group H increased significantly (p＜0.01) during oxygen inhalation.

It is concluded that oxygen inhalation improves Cp in mild COPD, but not in severe COPD, in spite of the fact that it decreases both NA and mPA in severe COPD. These results suggest that remodeling of pulmonary vascular structure is the cause of failure in improvement of Cp in severe COPD.