Objective:To investigate the changes of angiotensinⅡtype 1 receptor-activating antibody(AT1-AA)in patients with essential hypertension complicated with myocardial infarction and to explore the effect of AT1-A on rat coronary blood vessels. Methods:A total of 47 patients with essential hypertension complicated with myocardial infarction from June 2014 to July 2015 in our hospital were enrolled(hypertension and myocardial infarction group);96 patients with high blood pressure were taken as hypertension group

53 patients with myocardial infarction as myocardial infarction group and 65 healthy controls as healthy control group. AT1-AA titer level

positive rate and coronary vascular index under different concentrations of AT1-AA of four groups were compared. Results:AT1-AA titer level and positive rate were higher in hypertension and myocardial infarction group than in hypertension group and myocardial infarction group;AT1-AA titer level and positive rate were lower in healthy control group than in the other three groups

with statistically significant difference(P<0.05). Under 0

10-8

10-7

10-6 mol/L concentration

rat coronary vascular rings resting tension was(0.15±0.09)m N

(0.27±0.15)m N

(0.69±0.18)m N

(1.14±0.23)m N;coronary atherosclerotic plaque area was(2.45±0.47)%

(11.78±2.78)%

(19.16±2.52)%

(26.79±4.91)%

with statistics significances(P<0.05). And with the change of AT1-AA concentration

the trend was more significant(P<0.05). Rat coronary vascular rings resting tension(r=0.792

P=0.026)

coronary atherosclerotic plaque area(r=0.720

P=0.031)and AT1-AA were positively correlated. Conclusion:AT1-AA levels significantly are increased in patients with essential hypertension complicated with myocardial infarction. AT1-AA can lead to enhanced coronary vasoconstriction and expand the area of atherosclerotic plaque.