Changes in the derived central pressure waveform and pulse pressure in response to angiotensin II and noradrenaline in man

1. Peripheral pulse pressure provides a surrogate measure of arterial stiff ness. Analysis of the central pressure waveform allows assessment of centra l pulse pressure and arterial stiffness. The aim of the present study was t o assess the effect of vasoconstrictor drugs on pulse pressure amplificatio n and arterial stiffness in vivo. 2. Eight healthy male subjects (mean age 30 years) received an infusion of angiotensin II (1, 3, 6 and 10 ng kg(-1) min(-1)), noradrenaline (10, 30, 6 0 and 100 ng kg(-1) min(-1)) and matching placebo, in random order, on sepa rate occasions. Peripheral blood pressure and cardiac index were recorded n on-invasively. Pulse wave analysis was used to determine augmentation index (AIx), which provides a measure of systemic arterial stiffness, aortic sti ffness and central arterial pressure. 3. Infusion of both active drugs resulted in a significant increase in peri pheral mean arterial pressure (PMAP), peripheral vascular resistance, AIx, aortic stiffness and central pulse pressure, but only angiotensin II reduce d cardiac index. 4. Peripheral pulse pressure was unaffected by infusion of angiotensin II b ut increased with noradrenaline, which also produced a greater reduction in pulse pressure amplification than angiotensin II. However, the linear rela tionship of PMAP with both AIx and aortic stiffness did not differ signific antly between drugs. 5. These results demonstrate that intravenous infusion of angiotensin II an d noradrenaline increase aortic and systemic arterial stiffness. Despite a similar effect on both parameters, for a given change in PMAP, the two drug s had divergent effects on peripheral pulse pressure and pulse pressure amp lification. These data reveal that assessment of peripheral pulse pressure does not always reliably predict changes in central pulse pressure or arter ial stiffness.