RADIAL ARTERY COMPLIANCE IN YOUNG, OBESE, NORMOTENSIVE SUBJECTS

Obesity is characterized by a number of cardiovascular alterations, an d whether these alterations involve arterial compliance is unknown. In 12 young, obese, normotensive subjects (age, 23.9+/-1.3 years; mean+/ -SEM) and 12 age- and sex-matched lean control subjects we measured bl ood pressure, radial artery diameter, and radial artery compliance con tinuously over the systodiastolic pressure range with a Finapres devic e and recently developed echo-tracking device. Measurements were obtai ned at baseline and after prolonged ischemia, that is, when diameter a nd compliance are increased. Blood pressure values were normal in both groups (obese subjects: 109.2+/-4.9/68.2+/-2.7 mm Hg; lean control su bjects: 108.2+/-4.1/ 60.7+/-3.5 mm Hg), but in addition to a marked in crease in body mass index (38.5+/-0.8 versus 23.1+/-0.9 kg/m(2), P<.01 ), obese subjects showed a slight and nonsignificant increase in heart rate (71.1+/-3.2 versus 66.7+/-3.3 beats per minute, P=NS), increases in left ventricular wall thickness and left ventricular mass index (1 21.5+/-4.8 versus 103.4+/-3.3 kg/m(2), P<.01), no changes in plasma re nin activity and plasma norepinephrine (compared with normal values), and a marked reduction in total body glucose uptake (glucose clamp tec hnique). Obese subjects showed radial artery diameter and compliance v alues that were greater than those seen in control subjects throughout the systodiastolic pressure range. The differences were 13% (P<.05) a nd 96% (P<.01), respectively, and both diameter and compliance remaine d higher in obese than lean subjects after forearm ischemia. In obese and lean subjects baseline radial artery diameter values correlated hi ghly with body weight, body surface area, and body mass index. Thus, r adial artery compliance is increased in young, obese, normotensive sub jects, Whether these changes are related to functional factors or intr avascular or extravascular structural changes remains to be determined . The increase, however, is similar to what has been described in mild essential hypertension, emphasizing the similarity of the cardiovascu lar alterations in these two conditions.