The effects on blood flows of coronary artery by-pass grafts during intra-aortic balloon pumping.

The internal thoracic artery (ITA), as well as aorto-coronary by-pass grafts, has been used for widely coronary artery by-pass grafting. Intra-aortic balloon pumping (IABP) is the first choice for left ventricular support when low output syndrome occurs during coronary artery by-pass surgery. However, the effect of diastolic augmentation by IABP may vary to the type of grafts. Graft flow with and without IABP support were measured in six patients undergoing elective coronary artery bypass surgery requiring IABP at Kanazawa National Hospital. The patients ranged in age from 59 to 67 years, with a mean age of 63 years, and included one woman and five men. In all cases, the left ITA was dissected from the thoracic wall as pedicle, and anastomosed in situ to the left anterior descending artery. Saphenous vein grafts (SVGs) were used for aortocoronary by-pass to the obtuse marginal branches, the first diagonal branches, the left circumflex branches, and/or the right coronary artery. Blood flow in 6 ITAs, 11 SVGs to the left coronary artery systems, and three SVGs to the right coronary artery was measured by ultrasound transit-time flowmeter simultaneously with the electrocardiogram. Blood flows in ITA grafts and SVGs were measured during IABP assist and unassisting under hemodynamically stable conditions after discontinuing cardiopulmonary by-pass. The systolic and diastolic flows of each graft were measured using the peak of the R wave and the end of T wave on the electrocardiogram as the references for systole. Systolic flow during IABP were similar to unassisted flow in both ITA and SVGs.(ABSTRACT TRUNCATED AT 250 WORDS)