No abstract

Grafting an internal thoracic artery to a coronary artery with moderate stenosis remains controversial. Competitive flow from the native coronary artery has been proposed as the cause of distal narrowing and ultimate failure of the internal thoracic artery graft. We investigated intraoperative phasic blood flow in internal thoracic arteries grafted to coronary arteries with various degrees of stenosis and the influence of stenosis on postoperative angiographic findings. One hundred patients who underwent coronary artery bypass grafting of an internal thoracic artery to the left anterior descending coronary artery were divided into three groups according to degree of coronary stenosis. Group 1 included 39 patients who had 75% or less stenosis, group 2 included 34 patients with stenosis from 76% to 90%, and group 3 included 27 patients with stenosis greater than 90%. Mean flow and peak systolic flow of internal thoracic artery graft in group 1 were lower than those in group 2 (p < 0.01, p < 0.05). Peak diastolic flow in group 1 showed no difference from flows in groups 2 and 3. In eight patients in group 1, internal thoracic artery flow showed a predominant diastolic peak with characteristic systolic reversal as a result of competitive flow from the native coronary artery. Angiography at 1 month showed that the internal thoracic artery graft was patent in every case. Relative contributions of native coronary artery and internal thoracic artery flow to distal perfusion differed among the three groups (p < 0.001). In group 1, 15% of patients showed native-dominant flow, 62% showed balanced flow, and 23% showed internal thoracic artery-dependent flow. In group 2, 9% of patients showed native-dominant flow, 29% showed balanced flow, and 62% showed internal thoracic artery-dependent flow. In group 3, 96% of patients showed internal thoracic artery-dependent flow. String sign of the internal thoracic artery graft developed in only three patients; in two of these patients internal thoracic arteries were grafted to coronary arteries with stenosis of 50% or less and in the other patient there was competitive flow from a diagonal vein graft. Eleven of 13 internal thoracic arteries grafted to coronary arteries with stenosis of 50% or less did not show string sign. Competitive flow from a moderately stenotic coronary artery did not predispose the patient toward string sign of the internal thoracic artery graft in the presence of substantial diastolic internal thoracic artery flow. We conclude that internal thoracic artery grafting is acceptable for a moderately stenotic coronary artery.

Objective The continuous suture technique has numerous advantages as simple, quick, and effective for aortic valve replacement; however, it is technically difficult. We have modified the continuous suture technique and evaluated our new technique in patients with aortic stenosis. Methods Between July 2007 and May 2010, 86 patients with aortic valve stenosis underwent aortic valve replacement alone or with other concomitant cardiac procedures including mitral valve surgery in our hospital. The patients were randomly divided into two groups: group A (n = 43) in which the continuous suture technique with some modifications was used and group B (n = 43) in which the conventional interrupted suture technique was used. There were no statistical differences between two groups in age, sex, body surface area, concomitant cardiac procedures, blood loss, and postoperative extubation time. Results The aortic cross-clamp time, cardiopulmonary bypass time, operation time, and hospital stay were significantly shorter in group A than that in group B, and the valve size was significantly larger in group A. No perivalvular leak was detected in postoperative echocardiograms. All patients recovered satisfactorily without complications associated with suture technique or prosthesis. During follow-up of 4 to 38 months, there were no clinically significant complications in group A, while one patient in group B developed perivalvular leakage requiring reoperation 3 months after surgery. Conclusions Our modified continuous suture method is useful for aortic valve replacement in patients with aortic stenosis and beneficial for the patients because the procedure is less invasive and a larger valve can be implanted.