Evaluation of the cardiovascular function of older adult Rhesus monkeys by ultrasonography

OBJECTIVE: To evaluate the cardiovascular structure and function of older adult Rhesus monkey by utrasonography. METHODS: Sixteen monkeys aged from 17 to 20 years and weighing from 8.2 to 15.3 kg, six adults aged 7-8 years and weighing from 8.1 to 9.2 kg. All monkeys were determined to be free from hypertension, hyperglycaemia and cardiac disease. The normal values of index related to heart and blood vessels including structure, haemodynamics and systolic or diastolic function were detected by 2D, M-mode, pulsed Doppler and tissue Doppler echocardiography respectively under ketamine hydrochloride sedation. Meanwhile, blood pressures were also measured by electronic sphygmomanometer. Each monkey underwent repeated detections in 2 weeks and all data were analysed with statistical methods. RESULTS: Compared with young adult monkeys, the older's heart rate (HR), the left ventricular diastolic function and the compliance of big artery including right and left common carotid artery, bulbus caroticus, internal carotid artery and abdominal aorta were decreased and the associated indexes changed significantly (P < 0.05 or P < 0.01). Meanwhile, older monkeys exhibited significant increase in the aorta diameter (AO), amplitude of aortic wall (AAO), left atrial diameter (LAD), end diastolic volume of left ventricle (EDV), stroke volume (SV), left ventricular mass (LVM) (P < 0.05 vs. young adult monkeys); however, cardiac output (CO) only slightly increased but the difference did not reach the statistical significance (P = 0.418, P = 0.644 respectively). CONCLUSIONS: The present results demonstrated the profiles of cardiovascular function and structure in the older Rhesus monkeys. Older monkey is accompanied by diminished left ventricular diastolic function and big artery compliance. Ultrasonography provides a means to non-invasively evaluate the anatomy and function of the heart and blood vessel, and plays an increasingly important role in the drug evaluation against cardiovascular dysfunction.