The second peak of the radial artery pressure wave represents aortic systolic pressure in hypertensive and elderly patients.

BACKGROUND: Simultaneous measurement of ascending aorta and radial artery pressure shows that mean and diastolic pressures (DP) are in close agreement in normotensive adults, while systolic pressures (SP) are not. However, in the aortic pressure wave, a second systolic peak appears with increasing age and increases to represent the SP by age 32 yr, while in the radial artery, a second systolic deflection appears by age 40 yr. We suggest that the second radial systolic wave, sometimes seen during radial arterial pressure monitoring in older hypertensives, represents the aortic SP. We set out to evaluate whether the aortic and radial second systolic peaks agree, and since doubts exist about the agreement between aortic and radial DP in elderly hypertensive patients, we also assessed that relationship.
METHODS: We compared simultaneously recorded radial and aortic pressures from 21 anaesthetized adult patients using identical fluid-filled pressure measuring systems.
CONCLUSIONS: The second radial pressure peak agreed with that in the aorta within a mean of 0.6 (SD 1.5) mm Hg. The difference between DP in the aorta and radial artery was -1.4 (2) mm Hg. The radial-aortic SP and pulse pressure differences were 5.9 (7.6) and 7.3 (7.6) mm Hg, respectively. These results confirm that when the radial artery pressure wave shows a first and second, or only a second systolic shoulder/peak (on the right side of the pressure wave), the second represents the maximal ascending aortic SP, and that the radial and aortic DP are equivalent, even in older hypertensive patients.