|Budget Amount *help
¥2,200,000 (Direct Cost : ¥2,200,000)
Fiscal Year 1991 : ¥800,000 (Direct Cost : ¥800,000)
Fiscal Year 1990 : ¥1,400,000 (Direct Cost : ¥1,400,000)
The growth of the free internal mammary arty (IMA) graft pigs was examined. The animals were divided into 2 groups : Group I the free, pedicled IMA graft)and Group II (the free IMA was stripped). Operation were carried out under general anesthesia. The following results were obtained.
Using a 7-0 prolene suture, the free-IMA was anastomosed to the ascending aorta. The left anterior descending coronary artery (LAD) was incised by applying two threads at an interval of 1 cm. A tube was inserted via the incised LAD to enable coronary supply from the subclavian artery. The segment of the coronary artery between the two threads was incised vertically, followed by anastomosis of the IMA to the coronary artery using a 8-0 prolene with the beating heart. After anastomosis, the proximal coronary artery was ligated. 5 of the 12 animals were alive in Group I. Of these 5 animals, 3 died of bleeding or infarction -on day 1, 3 and 4 after surgery, respectively. _ In I of these 3 animals, the IMA show
ed thrombotic occlusion. In the remaining 2 animals, the IMA was patent. The other 2 animals died of malnutrition on day 31 and 40 after surgery. The IMA in these 2 animals were patent when examined by angiography. Weight gain in these 2 animals was poor (31->32, 30->31 kg). The length of IMA changed from 8.3 to 8.5 cm and from 8.6 to 8.7 cm in these animals. The diameter of the IMA (the mean of the diameter at 3 points) hardly changed (2.3->2.4, 2.2->2. lmm). Histological examination of the IMA revealed only mild hypertrophy of the intima and no injury. When Group II animals were subjected to a similar experiment, 2 of the 6 animals were alive after the operation. These 2 animals died of malnutrition on day 20 and 26 after surgery. The course of their weight was increases of 29.5 ->30 and 29 ->30 kg, respectively. One showed occlusion of the IMA. The other animal showed a reduction in IMA length from 8.0 to 7.9 cm and a decrease also in IMA diameter from 2.2 to 0.8 mm. The wall of IMA in this animal was irregular. Histologically, these 2 animals showed hypertrophy of the intima, thrombosis and fibrous hypertrophy of the adventitia. Thus, the early results were better in Group I (the IMA with a pedicle) than in Group II, although we cannot make a definite conclusion as to the superiority of one method over the other because none of the animals survived the long-term. Less