Safety and efficacy of radial artery conduits for coronary artery bypass surgery

Deposited with permission of the author. © 2001 Dr. Permyos Ruengsakulrach.Coronary artery bypass grafting (CABG) is the most common cardiac surgical operation performed in western countries, and is also increasingly being performed in developing countries. However the long-term results of CABG using the saphenous vein graft have not been satisfactory. Surgeons have therefore been seeking a better conduit. The radial artery (RA) is a potentially suitable alternative conduit and has to date provided good early results. This thesis investigates the utility of the RA as a coronary artery bypass graft from a number of perspectives. It demonstrates the safety of RA harvesting by examining hand collateral circulation using anatomical dissection, physical examination using the modified Allen test, measuring digital blood pressure, and examining the flow velocity in the digital artery using Doppler ultrasound. Anatomical examinations revealed consistent continuity between the RA and ulnar artery in the hand through either superficial or deep palmar arches. The modified Allen test was found to be useful as a screening test compared with the Doppler dynamic test and digital blood pressure index. A histological comparison was made between pre-existing intimal disease in the RA compared with that in the standard conduit the internal thoracic artery (ITA). The RA showed a higher prevalence and degree of intimal disease than ITA. Risk factors for intimal hyperplasia in the RA were age, diabetes, smoking and peripheral vascular disease. The only predictor for medial calcification was age. (For complete abstract open document