Bifurcated (“Y”) internal thoracic-coronary artery grafts

Coronary Artery Bypass Grafting Using a Bifurcated Internal Thoracic Artery

Coronary artery bypass grafting was performed successfully on a patient by anastomosing the left internal thoracic artery and its pericardiacophrenic branch to the obtuse marginal and the posterior descending coronary artery, respectively, to form a Y graft. Preoperative angiography of the internal thoracic artery had revealed the presence of an unusually large pericardiacophrenic branch almost the size of the main trunk, which allowed us to plan for bifurcated artery grafting.

Myocardial revascularization using branches of the left internal mammary artery

To increase the number of arterial grafts in patients with multivessel coronary disease, we have used branches of the left internal mammary artery (LIMA) as bypass grafts. From March 1990 to June 1993, 15 patients (13 males and 2 females) aged 38 to 65 years (mean 57 +/- 8), received a total of 30 LIMA branch anastomoses. The two terminal branches were used to perform a "Y" graft to the left anterior descending coronary artery territory in 13 patients. A pericardiophrenic branch was used in four cases. Five patients (33.3%) had complete myocardial revascularization using IMA only. There were neither early nor late deaths and all patients are free from angina at a mean follow-up of 20 months (6 to 45 months). However, early postoperative cardiac catheterization, performed in 12 patients (80%), revealed a 20% occlusion rate for each terminal branch and a 50% occlusion rate for the pericardiophrenic branch. Technically challenging due to the small diameter of the grafts, the terminal LIMA branches should be limited to selected patients when more conventional arterial or vein conduits are not available. More proximal branches have a higher occlusion rate and their use is not recommended.

Greater contractility of internal mammary artery bifurcation: possible cause of low patency rates

Coronary artery bypass grafting using bifurcation of the internal mammary artery (IMA) has been reported to have a poor patency rate. To test the hypothesis that the contractility (tendency for spasm) is greater at the bifurcation than at the main IMA, segments of the bifurcation and the distal section of IMA taken from patients with coronary artery bypass grafts were studied in organ baths. The IMA rings were set up at a physiologic pressure. Concentration-response curves were established for norepinephrine, endothelin-1, U46619, potassium, and glyceryl trinitrate (precontracted with 10 nmol/L U46619). Contraction forces were standardized (gram per mm circumference) at a pressure of 100 mm Hg. The diameter was 1.50 +/- 0.08 mm (n = 38) for the bifurcation and 2.03 +/- 0.07 (n = 42) for the main IMA (p < 0.0001). The standardized contraction force was greater in the bifurcation than in the main IMA for norepinephrine (0.82 +/- 0.06 versus 0.54 +/- 0.1; p = 0.02) and endothelin-1 (1.07 +/- 0.11 versus 0.69 +/- 0.07; p = 0.02). No differences were seen for potassium, U46619, or glyceryl trinitrate, whereas the effective concentration that induced 50% of maximal effect for U46619 was 6.17-fold lower in the bifurcation than in the main IMA (9.14 +/- 0.28 versus 8.35 +/- 0.09 -log M; p = 0.003), indicating higher sensitivity in the bifurcation.(ABSTRACT TRUNCATED AT 250 WORDS)