Intravenously and topically applied magnesium in the prevention of arterial thrombosis

Magnesium (Mg) has been shown to reduce platelet aggregation both in vitro and ex vivo, and this antiplatelet effect may be advantageous in the preven tion of arterial thrombosis. Previous animal studies have shown an antithro mbotic effect of Mg also in vivo, but mainly with higher Mg concentrations (similar to 3.0-4.0 mM). The objectives of the present study were to evalua te the antithrombotic effect of (1) intravenous Mg at a lower and clinicall y more relevant concentration and (2) topically applied Mg. The study compr ised 30 male rats, randomly assigned into 3 groups: (1) placebo group, (2) intravenous Mg group, and (3) topical Mg group. A thrombogenic lesion was e stablished by making a standardised arteriotomy in the right femoral artery . The vessel was transilluminated and thrombus formation was visualised dyn amically by in vivo microscopy and recorded on videotapes. Thrombus area wa s measured after ended experiment by computer-assisted image analysis. Intr avenously administered Mg, elevating the S-Mg level to 2.2 mmol/L, signific antly reduced the mean thrombus area (p<0.05) compared to the control group . Topically applied Mg significantly decreased the maximum thrombus area, w ithout any increase in S-Mg level (p<0.05), The Mg-treated groups showed no increase in bleeding complications. A transient fall in blood pressure was seen in the systemic Mg group, but blood pressures were not significantly different between any of the groups at the end of the experiment. In conclu sion, topically as well as intravenously infused Mg reduce arterial thrombu s formation in this in vivo rat model without compromising haemostasis, (C) 2000 Elsevier Science Ltd. All rights reserved.