Aim To investigate the relationship of plasma Apelin with left ventricular hypertrophy and carotid artery disease,and to observe the change of plasma Apelin levels in patients with hypertension.Methods 125 essential hypertensive patients and 31 healthy controls were selected.All patients with hypertension were divided into left ventricular hypertrophy group,intima-media thickeness group,carotid artery plaque group and simple hypertension group according to the measuring results by ultrasonography.The levels of plasma Apelin were determined by enzyme immunoassay.Results The plasma Apelin levels were significantly lower in left ventricular hypertrophy group(616±112 ng/L)than in control group(757±176 ng/L)and simple hypertension group(715±170 ng/L,P<0.01 or 0.05).The plasma Apelin levels were decreased in intima-media thickness group(613±133 ng/L)and carotid artery plaque group(592±146 ng/L)compared with control group and simple hypertension group(P<0.001 or 0.05).There were negative correlation between left ventricular mass index,intima-media thickness,carotid artery plaque index and plasma Apelin(respectively r=-0.253,r=-0.255 and r=-0.246,P<0.05).Conclusion Apelin may participate in the pathophysiological process of myocardial hypertrophy and atherosclerosis.