P-310: Capillary density and blood pressure in healthy elderly compared with healthy young subjects

Capillary rarefaction occurs in association with the development of high blood pressure in younger subjects as well as in established cardiovascular disease. Blood pressure usually increases with age in acculturated populations. Previous studies have suggested a reduction in capillary density with increasing age. We assessed capillary density and blood pressure in young subjects vs. older subjects matched for build and with normal blood pressure. We studied 39 healthy normotensive older Caucasian subjects, (23 female, mean age 66 years (range 57-79 years); height 1.69±0.01(SEM)m, weight 71±1kg) and 36 younger subjects (30 female, mean age 31 years (range 20-55); height 1.69±0.01m, weight 68±2 kg). We used intra-vital video-microscopy to examine the skin of the dorsum of the left middle phalanx before and after maximization of perfused capillaries with venous congestion at 60mmHg for 2 minutes. Blood pressure (Omron HEM 705CP) was significantly raised in older (132/77±3/1mmHg) vs. younger subjects 111/71± 2/1mmHg (P