Operative Interventions
Off-pump coronary artery bypass operations for both cohorts were
followed the standard care and processes of Hua Shan Hospital. In brief,
after general anesthesia and well prepared mechanical circulatory
support (both intra-aortic balloon pumps and extra-corporal circulation
units), patients were performed conventional median sternotomy incision
with harvesting of the left internal thoracic artery. Right internal
mammary artery and/or radial artery and saphenous vein graft was
performed as needed. Heparin was given at a low dose of 1 mg/kg to
achieve a target activated clotting time (ACT) of at least 280s before
ligation of the distal internal thoracic artery. The strategy of grafts
was decided after the pericardium opened and the size of target vessels
and heart assessed. Temporary stabilization of the target vessel
achieved by an Octopus tissue stabilizer (Medtronic, Inc., Minneapolis,
MN, USA) and if necessary supported with a deep pericardial traction
suture. Intraluminal shunts (ClearView Intracoronary Shunt; Medtronic)
and a blower mister (Guidant, Indianapolis, IN, USA) with carbon dioxide
and warm isotonic sodium chloride were used to remove blood from the
sites of arteriotomy and obtain a clear surgical field. An appropriately
sized intra-coronary shunt was placed to maintain perfusion of the
dependent myocardium and distal anastomosis performed using 7-0
polypropylene. Proximal anastomosis was done, if needed, using a partial
occluding vascular clamp on the ascending aorta, an aortomoy punch and
5-0 polypropylene. Ultrasounds were
routinely used to measure the patency and the flow of anastomosed
grafts.