Key result
Diltiazem achieves ~70% greater vasorelaxation than magnesium in precontracted aortic rings.
Why the study?
Perioperative vasospasm during cardiovascular surgery is a challenging problem and the comparative efficacy of magnesium and diltiazem in relieving vasospasm was evaluated.
Does diltiazem or magnesium produce greater vasorelaxation in phenylephrine-precontracted rat aortic rings?
Does diltiazem or magnesium produce greater vasorelaxation in phenylephrine-precontracted rat aortic rings?
Absolute Event Rate: 90% vs 53%
p-value: p=< 0.05
Both diltiazem and magnesium produce vasorelaxation in precontracted rat aortic rings, but diltiazem is significantly more potent.
Rat aortic findings warrant caution before clinical use; leaves open relative efficacy of magnesium versus diltiazem for perioperative vasospasm.
Perioperative vasospasm during cardiovascular surgery is a challenging problem. Several vasodilator agents are frequently utilized for its prevention in surgical practice. Magnesium and diltiazem both have known potential vasorelaxant effects. We planned to compare the efficacy of diltiazem and magnesium in relieving phenylephrine-precontracted rat aortic rings. Ten young adult female Wistar albino rats weighing 230-260 g were used in this study. The aortic rings in the organ bath equilibrated and reached their baseline tension. Precontraction was induced by 0.001 mmol/l phenylephrine and cumulative concentration-relaxation curves were obtained by consecutively increasing the addition of either diltiazem (10(-6)-0.1 mmol/l) or magnesium (0.1-10 mmol/l). The mean maximal relaxation responses observed by diltiazem and magnesium on separate aortic rings were 90 ± 3 and 53 ± 2%, respectively. The calculated EC50 of diltiazem was 0.01035 mmol/l, whereas the EC50 of magnesium was 4.064 mmol/l (P < 0.05). Both magnesium and diltiazem produced vasorelaxation on phenylephrine-precontracted rat aortic rings in this study, but the potency of diltiazem regarding the EC50 value was significantly higher than that of magnesium. Magnesium could be a candidate together with diltiazem to inhibit vasospasm on arterial grafts during coronary bypass surgery.
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Dogan et al. (2012) studied Phenylephrine-precontracted rat aortic rings (vasospasm model) (n=10). Diltiazem vs. Magnesium (0.1-10 mmol/l) was evaluated on Maximal relaxation response (p=< 0.05). Diltiazem produced a significantly higher maximal relaxation response (90% vs 53%) and greater potency (EC50 0.01035 vs 4.064 mmol/l, P<0.05) than magnesium in precontracted rat aortic rings.
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