The in vitro Effects of Iloprost with Other Vasodilators on the Human Internal Thoracic Artery

Purpose: We aimed (a) to analyze the effects of iloprost as a vasodilator on the human internal thoracic artery (ITA) and (b) to compare these effects with the effects of other vasodilators now being used in the clinic. Methods: Following transfer into only Krebs solution or into Krebs solution containing papaverine or iloprost, human ITA strips were then incubated only in Krebs or in Krebs with vasodilators that are generally used in clinical practice, such as diltiazem or glyceryl trinitrate. Cumulative concentration-contraction curves for noradrenaline (NA) and KCl were then established for these strips. Student's t-test and one-way analysis of variance followed by Tukey-Kramer tests were used to compare differences between groups. A p <0.05 was used to indicate significance. Results: Among the transfer solutions, papaverine (6.50 +/- 0.20) and iloprost (7.33 +/- 0.13) were significantly more potent than Krebs (8.46 +/- 0.75, p <0.001 and p <0.05) with regard to preventive effect on precontracted ITA with NA. Iloprost significantly relaxed the NA-induced precontracted ITA strips in the Krebs, papaverine, and iloprost groups. Diltiazem significantly relaxed the precontracted ITA with KCl in all storage groups. Conclusion: Iloprost may also prevent perioperative ITA spasm, but should be tested in the clinical setting. (Ann Thorac Cardiovasc Surg 2010; 16: 78-84)