Histomorphology of right versus left internal thoracic artery and risk factors for intimal hyperplasia

We compared the histological and morphometric properties of the right and left internal thoracic arteries and examined risk factors for intimal hyperplasia.

Paired segments of the right and left internal thoracic arteries obtained from 72 patients were studied. The transverse sections just distal to the most distal anastomoses were microscopically examined.

No significant difference was found between the right and left internal thoracic arteries in the median value of the lumen area (1.60 vs 1.52 mm(2), P = 0.33], intimal area (0.07 vs 0.05 mm(2), P = 0.80), width of intima (23 vs 21 μm, P = 0.88], width of media (149 vs 148 μm, P = 0.49), intima-to-media ratio (0.19 vs 0.17, P = 0.96) or percentage of luminal narrowing (3.6 vs 3.6, P = 0.86). No atherosclerotic lesion or medial calcification was seen in either artery. Intimal hyperplasia was identified in 72 segments from 50 patients. In a multivariate logistic regression model, estimated glomerular filtration rate (GRF) was significantly associated with intimal hyperplasia (odds ratio 1.35 per 10-ml/min/1.73 m(2) increase, 95% confidence interval 1.16-1.56, P < 0.01). In multivariate linear regression models, estimated GRF was significantly associated with the intima-to-media ratio (β-coefficient -0.009, 95% confidence interval -0.013 to -0.005, P < 0.01) and percentage of luminal narrowing (β-coefficient -0.011, 95% confidence interval -0.014 to -0.008, P < 0.01).

The right and left internal thoracic arteries have equivalent histological and morphometric properties. Lower estimated GRF is significantly associated with intimal hyperplasia.