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[Pathological changes of radial artery used for coronary artery bypass grafting and its related risk factors for intimal hyperplasia].

OBJECTIVE
To examine the degree of intimal hyperplasia and the prevalence of atherosclerosis in radial arteries taken from the patients undergoing coronary artery bypass grafting (CABG), and to analyze the risk factors to obtain some helpful information for choosing arterial conduits.


METHODS
Forty-one radial arteries and 11 internal mammary arteries samples were collected. The average age of patients was 48.5 years, and they all were male. Intimal hyperplasia, atherosclerosis, medial calcification were evaluated by routine histological methods, and the severity of diseases was measured on the percentage of luminal narrowing and the intima-to-media ratio (the intima area/media area). The risk factors for coronary heart disease were also analyzed.


RESULTS
Ninety-three percent (38 of 41) of radial arteries showed mild intimal hyperplasia, which was not regarded to influence blood flowing after CABG. As a part of them, 54% (22/41) of radial arteries had a lower than 25% of luminal narrowing, meanwhile 39% (16/41) of radial arteries had the percentage of luminal narrowing between 25% and 50%. Only 7% (3 of 41) of radial arteries were found to have occlusive lesions, which made arterial lumen decreased more than 75%. The 3 patients including 2 with severe atherosclerosis and another 1 aged 17 years was involved by fibromuscular dysplasia. The later vessel was discarded after harvesting. The percentage of luminal narrowing and the intima-to-media ratio were higher in radial artery than that in internal mammary artery (t = 3.00, 2.49, P < 0.05). The two parameters were positively correlated with age (r = 0.398, 0.310, P < 0.05), but this study failed to show any relationship between intimal hyperplasia of radial artery and coronary lesions and other risk factors. Medial calcification was not found by routine histological method in all cases.


CONCLUSION
Only mild intimal hyperplasia and no medial calcification are found in radial arteries used for CABG in the patients. Because the risk factors could not yet predict the severity of radial arterial lesions, this study strongly suggests that the Doppler ultrasonography and pre-operation clinical consideration should be emphasized to screen out some arteries with occlusive lesions.