Altered Aortic Properties in Elderly Orthostatic Hypertension

The present study was conducted to evaluate the validity and reproducibility of noninvasive brachial-ankle pulse wave velocity (baPWV) measurements and to examine the alteration of baPWV in patients with coronary artery disease (CAD). Simultaneous recordings of baPWV by a simple, noninvasive method and aortic pulse wave velosity (PWV) using a catheter tip with pressure manometer were performed in 41 patients with CAD, vasospastic angina, or cardiomyopathy. In 32 subjects (15 controls and 17 patients with CAD), baPWV was recorded independently by two observers in a random manner. In 55 subjects (14 controls and 41 patients with CAD), baPWV was recorded twice by a single observer on different days. baPWV were compared among 172 patients with CAD (aged 62 +/- 8 years); 655 age-matched patients without CAD but with hypertension, diabetes mellitus, or dyslipidemia; and 595 age-matched healthy subjects without these risk factors. baPWV correlated well with aortic PWV (r=0.87, p<0.01). Pearson's correlation coefficients of interobserver and intraobserver reproducibility were r=0.98 and r=0.87, respectively. The corresponding coefficients of variation were 8.4% and 10.0%. baPWV were significantly higher in CAD patients than in non-CAD patients with risk factors, for both genders (p<0.01). In addition, baPWV were higher in non-CAD patients with risk factors than in healthy subjects without risk factors. Thus, the validity and reproducibility of baPWV measurements are considerably high, and this method seems to be an acceptable marker reflecting vascular damages. baPWV measured by this simple, noninvasive method is suitable for screening vascular damages in a large population.

Arterial stiffness is an important determinant of cardiovascular risk. Augmentation index (AIx) is a measure of systemic arterial stiffness derived from the ascending aortic pressure waveform. The aim of the present study was to assess the effect of heart rate on AIx. We elected to use cardiac pacing rather than chronotropic drugs to minimize confounding effects on the systemic circulation and myocardial contractility. Twenty-two subjects (13 male) with a mean age of 63 years and permanent cardiac pacemakers in situ were studied. Pulse wave analysis was used to determine central arterial pressure waveforms, non-invasively, during incremental pacing (from 60 to 110 beats min-1), from which AIx and central blood pressure were calculated. Peripheral blood pressure was recorded non-invasively from the brachial artery. There was a significant, inverse, linear relationship between AIx and heart rate (r = -0.76; P < 0.001). For a 10 beats min-1 increment, AIx fell by around 4 %. Ejection duration and heart rate were also inversely related (r = -0. 51; P < 0.001). Peripheral systolic, diastolic and mean arterial pressure increased significantly during incremental pacing. Although central diastolic pressure increased significantly with pacing, central systolic pressure did not. There was a significant increase in the ratio of peripheral to central pulse pressure (P < 0.001), which was accounted for by the observed change in central pressure augmentation. These results demonstrate an inverse, linear relationship between AIx and heart rate. This is likely to be due to alterations in the timing of the reflected pressure wave, produced by changes in the absolute duration of systole. Consideration of wave reflection and aortic pressure augmentation may explain the lack of rise in central systolic pressure during incremental pacing despite an increase in peripheral pressure.