Human cadaveric coronary artery vasoreactivity is dependent on anatomic location and postmortem interval

Background: Clinical observations suggest that the right coronary artery (RCA) has a different vasoreactivity when compared with the left anterior descending artery (LAD) and the left circumflex artery (LCx). Methods: The proximal segment of 31 coronary vessels (11 RCA, 11 LAD, nine LCx) were harvested from 11 donors. Rings from these vessels were suspended in organ baths containing physiologic solution at 37°C. Isometric tension studies using cumulative dose response curves were performed with norepinephrine, serotonin, histamine, and acetylcholine. Following these studies, each ring was histologically assessed for morphometric changes and signs of atherosclerosis. Results: Eleven of 31 vessels reacted to 60 mmol/L of KCl. The probability that a vessel would respond depended on the postmortem interval; 88% of vessels harvested within 4 hours reacted. The RCA generated a greater maximum tension than either of the left coronaries, irrespective of the postmortem interval. Dose response curves and median effective dose (ED₅₀) values for each agonist from the RCA, LAD, and LCx were similar. There was no correlation between functional studies and either morphology or morphometric measures. Conclusions: This study supports the view that the RCA has a different vasomotor profile than its left-sided counterparts.