Low intracellular magnesium levels promote platelet-dependent thrombosis in patients with coronary artery disease

Background Although reduced intracellular levels of magnesium have been described in patients with acute myocardial infarction, its significance as a regulator of thrombosis remains unknown. Methods and Results To determine whether reduced intracellular levels of magnesium enhance platelet-dependent thrombosis, we evaluated 42 patients with coronary artery disease (CAD) by exposing porcine aortic media to their flowing unanticoagulated venous blood for 5 minutes by using an ex vivo perfusion (Badimon) chamber. Baseline analysis demonstrated significant associations between intracellular levels of magnesium, platelet-dependent thrombosis (P = .02), and platelet P-selectin (CD62P) expression (P < .05). Patients were divided into 2 groups: below (n = 22) and above (n = 20) the median intracellular levels of magnesium (1.12 μg/mg protein). There were no significant differences in age, body mass index, serum lipids, fibrinogen, platelet count, or serum magnesium levels between the two groups. Platelet-dependent thrombosis was significantly higher in patients with intracellular levels of magnesium below compared with above median (150 ± 128 vs 45 ± 28 μm2/mm, P < .004). Neither platelet aggregation nor CD62P expression was significantly different between the two groups. Conclusions Platelet-dependent thrombosis was significantly increased in patients with stable CAD with low intracellular levels of magnesium, suggesting a potential role for magnesium supplementation in CAD. (Am Heart J 2000;140:212-8.)