Intercostal artery: histomorphometric study to assess its suitability as a coronary bypass graft.

To assess potential suitability of the intercostal artery as a conduit in myocardial revascularization a histomorphometric study of the fifth intercostal artery (n = 11) and intercostal arteries other than the fifth (n = 9) was conducted. All arteries were harvested at autopsy in 11 individuals (mean age, 75 years). The length of the intercostal arteries varied from 22 to 35 cm (mean, 29.4 cm). Three combinations of histologic patterns were seen along the course of the intercostal artery: a proximal elastic segment followed by subsequent elastomuscular and muscular segments (n = 3), a proximal elastomuscular segment with the remainder of the artery being muscular (n = 6), and a completely muscular pattern (n = 2). The mean luminal diameter of the fifth intercostal arteries varied from 1.4 +/- 0.3 mm at the origin to 0.9 +/- 0.2 mm at 30 cm (30% to 40% decrease in diameter due to the flaccid state and rigor mortis). The mean intimal thickness at these locations was 54 +/- 38 microns and 25 +/- 16 microns and the mean thickness of the media was 205 +/- 38 microns and 70 +/- 45 microns. The histologic findings, mean luminal diameter, and mean diameter of the intima and the media were similar in the intercostal arteries other than the fifth. Our study demonstrates that the intercostal artery has a relatively thin intima and media, the latter being elastic or elastomuscular in the proximal segment in the majority of the investigated arteries, which are favorable properties with regard to its potential suitability as a coronary bypass conduit.