Two groups of left pulmonary-subclavian artery anastomosis were done in 26 adult mongorel dogs. For the first group, the distal end of the subclavian artery was anastomosed to the side of the left pulmonary artery, and for the second group, the subclavian end was anastomosed to the proximal end of the left lower lobe pulmonary artery.
Among them, 6 died of bleeding or anesthetic failure during the day of operation, 10 survived 1 to 106 days and the other 10 were sacrificed at various interval.
To investigate the relationship between hemodynamic stress and temporal evolution of the pulmonary vascular lesions, the pulmonary and femoral artery pressures, arteriogram and pathohistological specimens were obtained.
The following results were obtained.
1. The postoperative pulmonary artery pressures were within normal limits except 2 dogs in the first group, but in all 12 dogs of the second group, they were in moderate to maked pulmonary hypertension level.
2. After subclavian pulmonary anastomosis, both groups dogs showed increased femoral artery pulse pressure.
3. The pulmonary vascular changes were more severe and appeared earlier in the second group dogs compared with the first group.
4. The earliest vascular changes appeared in the media of the small muscular arteries and arterioles.
5. Various vascular changes were produced in 2 or 3 months. Thereafter, the charges were stationary.
6. Among the first group, two long-term servivors (No. 705 & 713) which had normal pulmonary artery pressure under the anesthesia, also showed various vascular changes as other pulmonary hypertensive dogs.
7. In the early stage m3dial hypertrophy, interruption of elastic lamellae were found in the small muscular arteries and arterioles, which were followed by intimal proliferation and thrombosis. These findings may suggest some evidences of trauma to the vessels.
8. Pulmonary arteriograms showed irregularity of the intima of the large and medium sized arteries, abrupt ending of some of the small arteries and narrowing of the anastomosis.
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