Human gastroepiploic artery has greater chymase activity than the internal thoracic artery

Objective: Recent reports have demonstrated that long-term patency of the gastroepiploic artery (GEA) in coronary artery bypass grafting (CABG) is less satisfactory compared with the internal thoracic artery (ITA). However, the reason has not been fully elucidated. Angiotensin II is known to play an important role in the development of intimal hyperplasia, we hypothesized that the GEA is different from the ITA with respect to angiotensin II-forming ability. Accordingly, we measured activities of angiotensin II-forming enzymes, angiotensin-converting enzyme (ACE) and chymase, in human GEA and ITA. Methods: Remnant of the GEAs and ITAs were obtained from 24 patients who underwent CABG in which both conduits were used simultaneously. Activities of ACE and chymase were measured by using the extract form the GEA or ITA. Sections of the GEA or ITA were immunohistochemically stained with anti-human chymase antibody. Results: The ACE activity of the GEA (0.28 ± 0.16 mU/mg protein) was greater than that of the ITA (0.18 ± 0.11, p < 0.001). The chymase activity of the GEA (11.11 ± 7.15 mU/mg protein) was also greater than that in the ITA (7.13 ± 4.89, p < 0.001). The density of chymase-positive cells in the GEA (3.8 ± 4.2 cells/mm²) was greater than that in the ITA (1.1 ± 1.2, p < 0.01). Conclusion: Activities of both ACE and chymase were significantly greater in the GEA compared with the ITA. The GEA may be different from the ITA with respect to potential ability of angiotensin II-formation.     

Kinking of skeletonized internal thoracic artery graft

A 66-year-old woman underwent coronary artery bypass grafting (CABG). Postoperative angiography on postoperative day (POD) 11 revealed that right internal thoracic artery (RITA) anastomosed to left anterior descending artery (LAD) had a kinking. The angiography performed 30 months after operation revealed no specific changes in the kinking of RITA and in the left ventricular function. Another case was a 74-year-old man with chronic renal failure under hemodialysis. He underwent CABG with left internal thoracic artery (LITA) to LAD. Post-operatively he had chest pain during hemodialysis. On POD 10, angiography revealed that LITA had a kinking with moderate stenosis and normal left ventricular function. The angiography performed 10 months after operation revealed no specific changes in the kinking of LITA. However, left ventriculography revealed akinesis in the antero-apical region. It suggested that the viability was lost due to the graft kinking of LITA and steal phenomenon on hemodialysis.     

Arteriosclerosis of the gastroepiploic and internal thoracic arteries

Arteriosclerosis of the right gastroepiploic artery (GEA) and the internal thoracic artery (ITA) were compared by pathological observation. Specimens were obtained from 35 patients who underwent coronary artery bypass grafting with simultaneous use of these two kinds of arterial grafts. Degree of arteriosclerosis was classified in five categories: 0, normal; 1, luminal narrowing less than 25%; 2, luminal narrowing between 25% and 50%; 3, luminal narrowing greater than 50%; and 4, overt atherosclerosis with ulceration or calcification. The number of arteries with degree 0, 1, 2, 3, and 4 was 16 (46%), 15 (43%), 3 (9%), 0, and 1 (3%) in GEA and 27 (77%), 8 (23%), 0, 0, and 0 in ITA, respectively. Incidence of degree 0 was higher in ITA, but differences were not significant. The mean wall thickness was 0.30 +/- 0.13 mm in GEA and 0.21 +/- 0.07 mm in ITA (p less than 0.05). In 23 patients who underwent postoperative angiography, all 46 arterial grafts were patent without focal stenosis. We conclude that GEA has slightly more intimal thickening than ITA, but significant luminal narrowing caused by arteriosclerosis is rare. Gastroepiploic artery can be expected to be a suitable conduit for coronary artery bypass grafting.     

Pleuropulmonary morbidity: internal thoracic artery versus saphenous vein graft

Although use of the internal thoracic artery (ITA) for coronary artery bypass grafting results in superior graft patency and improved patient survival, our initial clinical observations suggested an increased incidence of pleuropulmonary morbidity with its use. One hundred consecutive patients with left ITA grafts were studied prospectively and compared with a consecutive retrospective group of 100 patients undergoing coronary artery bypass grafting with saphenous vein grafts only. Preoperative, postoperative day (POD) 2, POD 6, and postoperative week 8 chest roentgenograms were analyzed for atelectasis and effusion. Postoperative left lower lobe atelectasis was common in both groups on both POD 2 (saphenous vein, 43%, versus ITA, 53%; not significant) and POD 6 (saphenous vein, 40%, versus ITA, 41%; not significant). There was a significantly higher incidence of pleural effusion on POD 6 in the ITA group (84% versus 47%; p less than 0.05) but most of these were small. There was more chest tube drainage (1,413 versus 1,028 mL; p less than 0.01) and a greater need for secondary thoracostomy or thoracentesis (4% versus 0%) in the ITA group. The left pleural space was opened in 67 of the 100 ITA patients but pleurotomy did not appear to influence postoperative morbidity. We conclude that use of the internal thoracic artery for coronary artery bypass grafting results in a small but significant increase in pleuropulmonary morbidity.     

Pharmacological response of internal mammary artery and gastroepiploic artery

Pharmacological response of coronary artery bypass conduit is of great importance. This study was designed to clarify the contractile properties of internal mammary artery and gastroepiploic artery obtained from coronary revascularization. The response to ergonovine, serotonin, and phenylephrine was examined by isometric contraction recording apparatus. The concentration-response relation of both internal mammary artery and gastroepiploic artery to ergonovine, serotonin, and phenylephrine showed similar sigmoid curves. There were no significant differences in developed tension between internal mammary artery and gastroepiploic artery at any concentration for any agent. There were no significant differences in the 50% effective dose value for any agent between internal mammary artery and gastroepiploic artery. Internal mammary artery and gastroepiploic artery are reported to be similar in terms of size, flow capacity, and freedom from atherosclerosis. This study shows their equivalence from a pharmacological viewpoint.     

In situ right internal thoracic artery graft for revascularization of circumflex artery

In 285 patients, the right internal thoracic artery, routed through the transverse sinus, was in most cases anastomosed to the circumflex branches. In 278 cases, the left internal thoracic artery was simultaneously used for revascularization of the left anterior descending artery. Two patients died (mortality rate 0.7%). Postoperative early angiography on 278 patients revealed a high graft patency of 97.8% for the right internal thoracic artery and 96.9% for the left internal thoracic artery. A long-term follow-up study was performed on the first consecutive 115 patients who survived the operation. Seven patients died, 2 due to cardiac causes. Angiographic assessment was performed in 73 patients (67%) at an interval of 28.8 to 93.1 months (mean 58.9 months). Five right internal thoracic arteries were occluded and sledlike right internal thoracic artery grafts were present in 2 patients. Two of them had been confirmed in the previous early study to be not patent. Insufficient data was obtained in 4 patients. The perfect patency rate of the right internal thoracic artery was 89.9% (62/69). Five left internal thoracic arteries were occluded, providing a perfect patency rate of 92.3%. There was no significant difference between the success rate using the right internal thoracic artery and that resulting from using the left internal thoracic artery. We conclude that coronary revascularization using this technique provides good clinical results and excellent early and late patency of the right internal thoracic artery.     

Long-term follow-up of total arterial myocardial revascularization using exclusively pedicle bilateral internal thoracic artery and right gastroepiploic artery

Objective: In order to reduce remote cardiac events associated with graft occlusions, arterial conduits are being increasingly utilized in coronary artery bypass grafting (CABG). While the internal thoracic artery (ITA) is the graft of choice for CABG, it is sometimes difficult or impossible to obtain a complete arterial revascularization only with ITAs in three-vessel diseases. We present our experience with total arterial myocardial revascularization with bilateral internal thoracic artery (BITA) and right gastroepiploic artery (rGEA). Methods: From April 1994 to January 2004, 174 patients (165 male, mean age 55.9±7.4) underwent coronary artery bypass procedure with exclusive use of BITA and rGEA. Left ventricular ejection fraction ranged from 20 to 68% (mean 55.9±6.8%). Seven patients (4%) had poor ejection fraction (<0.30), 23 (13, 2%) had acute myocardial infarction, 14 (8%) had left main disease. The mean CPB time was 96.9±15.7 min and the mean cross clamping time was 70±14.2 min. The mean number of distal anastomoses was 3.3±0.5 per patient. Results: Early mortality was 1.7%. The patients were followed for up to 9 years (mean follow-up time 6.3±2.6 years). Actuarial freedom from cardiac death (including hospital death) was 97.6%, at 9 years after the operation. Actuarial freedom from angina and cardiac events at 9 years was 79, 5% and 77, 6%, respectively. No perioperative myocardial infarction occurred. None of the patients needed a redo-CABG after leaving the hospital. Conclusions: This study indicates that the myocardial revascularization in young patients with three-vessel disease using exclusively pedicle BITA and rGEA provides excellent 9-year patient survival and improvement in terms of freedom from return of angina pectoris and freedom from any cardiac-related event. These results encourage the more extensive use of BITA and rGEA in selected patients with three-vessel coronary disease.     

Coronary artery bypass grafting with gastroepiploic artery composite graft

BACKGROUND: To achieve better results after coronary artery bypass grafting (CABG), arterial conduits are the first choice in multiple CABG for younger patients. We present here the early results of CABG with gastroepiploic artery (GEA) composite graft with free radial artery (RA) to revascularize right coronary artery or left circumflex artery in addition to internal thoracic artery to left anterior descending artery. METHODS: Between July 1997 and June 1998, 13 patients received CABG with GEA (larger caliber than 2.0 mm) composite graft. We have assessed the early results. RESULTS: There was no postoperative death or major morbidity. Postoperative angiogram was performed in 11 patients and all conduits were patent. Postoperative exercise stress test was done in 13 cases and showed no ischemia. CONCLUSIONS: Multiple CABG with arterial conduit can be performed by this procedure. The free RA functioned from secondary branches derived from proximal GEA. In conclusion, this procedure seems to be safe and effective, and both long-term patency and better quality of life may be expected.     

A new technique for the old arterial graft: internal thoracic artery

The internal thoracic artery (ITA) is the gold-standard conduit for coronary artery bypass surgery. It stays patent well in the long-term period, and this evidence is directly related to the superior later outcome in terms of longevity. Coronary artery bypass grafting with multiarterial grafts can be performed safely, and better long-term result can be expected with the use of arterial conduits, especially ITA. We describe a simple and practical technique for the left ITA grafting by dividing the ITA graft and using its proximal and distal parts in situ for the distal left anterior descending (LAD) artery and the obtuse marginal artery grafting.     

Complete myocardial revascularization with bilateral internal thoracic artery T graft

BACKGROUND: The internal thoracic artery is widely recognized as the ideal graft for coronary artery bypass procedures. However, because of the inadequate length of the conduit, use of bilateral internal thoracic artery grafting was not suitable for complete revascularization. To overcome this limitation, the T graft was introduced in the 1990s. We decided to prospectively assess the safety of this technique. METHODS: One hundred six patients with a mean age of 51.5 years underwent complete revascularization with an internal thoracic artery T graft. Mean left ventricular ejection fraction was 0.60 (range, 0.22 to 0.85). RESULTS: No patient required reexploration for bleeding, and no patient died within 30 days after operation. On the basis of electrocardiographic changes, 3 patients sustained a perioperative myocardial infarction. One patient had a sternal wound infection. Mean follow-up was 35 months (range, 15 to 61 months). The actuarial survival rate was 99% +/- 1% at 5 years. No myocardial infarctions were reported during the follow-up. Seven patients had recurrent angina. Eighty patients (76%) underwent postoperative stress tests, and 90% had negative results. CONCLUSIONS: Complete myocardial revascularization with the T graft is a safe and reliable technique with excellent midterm results.     

Effects of ultrasonic skeletonization on internal thoracic and gastroepiploic arteries for coronary artery bypass grafting.

OBJECTIVE: There are few data available on the effect of ultrasonic skeletonization with the harmonic scalpel on internal thoracic artery (ITA) and gastroepiploic artery (GEA) vessel function. METHODS: Rings of segments of the skeletonized ITA, pedicled ITA, skeletonized GEA, and pedicled GEA were studied. Arterial segments were treated with high KCl and norepinephrine (NE) to obtain smooth muscle contractions. Endothelium-dependent and independent vasorelaxant potencies in 10(-6)mol/l NE-pre-constricted arteries were assessed by acetylcholine (ACh), and isosorbide dinitrate (ISDN) and diltiazem, respectively. RESULTS: There were no differences in contractile potencies induced by high KCl and NE between the rings cut from skeletonized and pedicled grafts. The rings from skeletonized and pedicled vessels also showed equal sensitivity to ISDN and diltiazem. However, the rings from pedicled grafts showed greater relaxation responses to ACh than rings from skeletonized grafts. CONCLUSION: Ultrasonic complete skeletonization with the harmonic scalpel may retain smooth muscle function of skeletonized grafts, whereas endothelial function of ultrasonic skeletonized grafts may be significantly compromised.     

Healing of the intimal dissection of the internal thoracic artery graft

We report healing of the intimal dissection of an internal thoracic artery graft. Triple coronary artery bypass grafting was performed using left internal thoracic artery and saphenous vein grafts. One month after operation, the intimal dissection of the internal thoracic artery graft was clearly visible by coronary angiography; however, after 1 year of only medical treatment consisting of warfarin, ticlopidine, and nitrate, the intimal dissection was undetectable by coronary angiography.     

Spontaneous recanalization of functionally occluded bilateral internal thoracic artery T graft

Functional occlusion of the left internal thoracic artery T graft is reported. The patient underwent triple coronary artery bypass grafting with bilateral internal thoracic artery, anastomosing in situ to the left internal thoracic artery to the left anterior descending artery, free right internal thoracic artery to the obtuse marginal and posterolateral branch of the left circumflex artery. Early angiography showed occlusion of the in situ left internal thoracic artery to the moderately stenosed left anterior descending artery and patent side arm to circumflex. However, mid-term angiography revealed restoration of the left internal thoracic artery flow. A negative exercise stress test was noted throughout the postoperative period. Flow competition with a native coronary artery may be responsible for functional occlusion of the left internal thoracic artery.