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    The Evaluation of In Vitro Effects of Dipyridamole on Coronary Artery Bypass Grafts
    (Galenos Publ House, 2011) Ege, Turan; Karaca, Okay Guven; Gur, Ozcan; Karadag, Hakan; Gurkan, Selami; Duran, Enver
    Objective: The aim of this study is to evaluate the efficacy of dipyridamole in relieving the vasospasm of coronary artery bypass grafts. Material and Methods: Twenty two patients who underwent elective coronary artery bypass grafting (CABG) were admitted to the study (Men/Women:14/8, mean age: 62.4 +/- 8.8 years). Ten samples from left internal mammary(LIMA), radial arterial (RA) and saphenous vein (SV) grafts were collected for each. The samples were transported to the vascular laboratory in 4 C Krebs solution. Submaximal smooth muscle contraction was achieved first by 10-7M of phenylephrine solution. Dipyridamole was then added, starting from a concentration of 10-9M to a concentration of 10-3.5M in two minutes intervals and half logarithmic dose increments. The concentration-response curves were obtained of the vasodilatation response relative to the begining. Results: In the LIMA graft samples, the vasodilation response to dipyridamole was 43.2 +/- 1.6% and 97.6 +/- 4.1% at concentrations of 10-6M and 10-3.5M respectively. In RA graft samples, the vasodilation response to dipyridamole was 36.3 +/- 1.8% and 95.3 +/- 2.7% at concentrations of 10-6M and 10-3.5M respectively. In SV graft samples, however, the vasodilation response to dipyridamole was 43.2 +/- 1.4% and 96.6 +/- 2.2% at concentrations of 10-6M and 10-3.5M respectively. Conclusions: The amplitude of relaxation response to dipyridamole of all grafts samples were similar, without statistically significant difference among the IMA, RA and SV grafts in the in vitro tissue bath system. These results prove that dipyridamole has a potential use as a vasodilatatory drug in all graft types.
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    In vitro effects of amiodarone on coronary artery bypass grafts
    (Baycinar Medical Publ-Baycinar Tibbi Yayincilik, 2015) Karaca, Okay Guven; Ege, Turan; Canbaz, Suat; Gur, Ozcan; Karadag, Cetin Hakan; Ecevit, Ata Niyazi; Kalender, Mehmet
    Background: This study aims to investigate the effects of amiodarone on the most commonly used grafts, internal thoracic artery (ITA), saphenous vein (SV), and radial artery (RA) in organ bath. Methods: Twenty patients (16 males, 4 females; mean ages 58.4 +/- 9.9 years; range 38 to 80 years) who underwent isolated coronary artery bypass graft (CABG) surgery between May 2008 and October 2008 were included in this study. Internal thoracic artery, saphenous vein, and radial artery grafts were harvested. Specimens were taken to laboratory in +4 degrees C Krebs solution. Specimens were suspended in 10 ml organ bath containing Krebs solution. Results: Amiodarone caused relaxation in all grafts (ITA, RA, SV) between 10(-9)-10(-3,5) M concentration in a dose dependent manner (p<0.01). Maximum relaxation rates (mean) induced by amiodarone were 78.9%, 74.9% and 66.5% for ITA, RA and SV, respectively. Conclusion: Although we did not evaluate the endothelium-independent relaxation response in this study, higher rates of relaxation response were observed with ITA grafts comparing to other grafts, and these results were compatible with literature. According to the results of this study, amiodarone-class III antiarrhythmic agent- caused vasodilation in all three grafts in vitro. Vasodilator effect of amiodarone on grafts may help to increase patency rates.