Selection of conduit

Selection of conduit

• Venous grafts The long saphenous vein is the most commonly used venous conduit as it is straightforward to harvest, provides good length and is easy to handle. Historical studies showed a limited long - term patency rate for long saphenous vein grafts (50–60% at 10 - years). However, recent studies suggest that early postoperative use of lipid-low ering agents and antiplatelet agents such as low-dose aspirin can improve vein graft long-term patency . In - assessing the patient preoperatively , the legs should be checked for varicose veins. Alternative vein conduits include the short - saphenous vein or upper limb veins such as the cephalic vein; however, these grafts are associated with poorer long-term patency rates. Arterial grafts The left internal mammary artery (LIMA), or internal thoracic - artery , has become the conduit of choice for LAD grafting. Evidence from the mid-1980s to the present day suggests a 10-year patency rate of >95%, with a lower reoperation rate. As this arterial conduit avoids the late complication of vein graft atherosclerosis, interest has focused on the use of bilateral internal mammary artery grafts although there is currently no supporting evidence for this. The use of the radial artery as an alternative arterial bypass graft has undergone a recent revival. This has been driv en by the belief that total arterial revascularisation (avoiding venous conduits) might improve long-term results of coronary surgery . Di ff erent studies have demonstrated excellent patency rates at 1 and 5 years with this strategy . When assessing a patient in - whom a radial artery harvest is planned, an Allen’s test should be performed. The alternative would be vascular assessment of the radial and ulnar arteries with ultrasound. Allen’s test /uni25CF /uni25CF /uni25CF

Figure 59.4 Open long saphenous vein harvesting is performed through an incision starting anteriorly to the medial malleolus of the ankle, extending to the groin if necessary. Figure 59.5 A pedicled left internal mammary artery is dissected off the chest wall and divided distally after systemic heparinisation. It is left attached to the subclavian artery proximally. The patient repeatedly clenches and unclenches the /f_i st while the surgeon compresses both radial and ulnar arteries digitally at the wrist; this empties blood from the hand The hand is then relaxed and compression of the ulnar artery is released; the speed of returning colour to the hand is assessed If colour returns in 5–7 seconds, patency and collateral /f_l ow from the ulnar artery are con /f_i rmed and it is safe to harvest the radial artery