Abstract： To the Editor:Hypertension and coronary heart disease are commonly seen in the elderly population.The pathophysiology of their development is closely related to the mechanism of hemostasis and thrombosis,where the involvement of platelets is pivotal.Platelet microparticle (PMP) is an ultra-microvesicle released in the process of platelet activation,and holds important function in hemostasis and thrombosis.1 We measured concentration of PMP in peripheral blood among patients with elderly essential hypertension (EH) complicating with coronary heart disease (n=22,ages range from 68 to 84 years),and elderly healthy volunteers (n=20,ages range from 63 to 82 years).The results showed that PMP in patients with EH complicating with CAD was greater that that in healthy volunteers (Table 1).