慢性肺性心症例の肺循環動態に及ぼすnifedipineの影響

Effects of nifedipine on pulmonary circulation in patients with chronic cor pulmonale

　慢性呼吸器疾患に由来する肺高血圧症は右室肥大を引き起こし，ついには右心不全を呈するに至る^1,2）。最近，各禰血管拡張剤が肺高血圧を低上下させ，右心機能を改善させるとの報告が多くみられる^3〜6）。しかしながら，血管拡張剤がいつも有効であるとは限らず，いくつかの問題点も指摘されている^7〜10）。Ca^＋＋拮抗剤であるnifedi—pineは低酸素下における肺動脈収縮の軽減に有効であるとの報告が多い反面^11〜13），逆にnifedipine投与後に肺動脈圧の上昇を認め，右心不全症状が発現したとの報告も認められる^7）。今回我々は，慢性安定期にある肺性心症例にnifedipfneを投与し，肺循環動態に与える影響につき検討したので報告する。

The effects of sublingual nifedipine (10 mg) on right ventricular performance were studied in 13 patients with pulmonary hypertension secondary to chronic lung disease.

Total pulmonary vascular resistance (TPVR) dec-reased from 8.3±7.0 to 6.6±5.2 unit (mmHg×min/l) after nifedipine administration (p <0. 05). Cardiac index (CI) increased 3.7±1.2 to 4.5±1.6 l/min/m² (p<0.01). There was no significant fall in pulmo-nary arterial mean pressure (PAMP), exacerbations of pulmonary hypertension were observed in two patients. Mean arterial pressure decreased from 94.6±11.0 to 86.2±823 mmHg (p<0.01), in associa-tion with a reflex increase in heart rate from 86.5± 19.2 to 95.7±23.3 beats/min (p <0.01). There was no significant fall in Pa_O2, and Pv_O2,while O₂-trans-port increased significantly (p<0.01).

In conclusion, nifesipine induced a significant inc-rease in CI and O₂-transport, however no change in PAMP. Nifedipine has not always been success-ful and possible harmful side effects have been demonstrated. The administration of active vasodi-lator agents in patients with pulmonary hypertension secondary to chronic lung disease clearly requires careful monitoring of intravascular pressure and right ventricular performance in order to detect unsuspected untoward effects.