Mechanical principles. Arterial stiffness and wave reflection.
Arterial (and predominantly aortic) stiffening with age is now acknowledged as the cause of isolated systolic hypertension, and the predominant cause of cardiac failure in the elderly. Aortic stiffening is gauged clinically from increase in brachial pulse pressure, but this underestimates change with age, since aortic pulse pressure increases far more than brachial (on account of substantial amplification of the peripheral arterial pressure pulse in young adults). Aortic stiffness can be measured as pulse wave velocity, but this too underestimates ill effects on the heart and central vessels, since the direct effect is amplified by early return of wave reflection. Ill effects of arterial stiffening can best be assessed through analysis of pressure wave contour from the carotid or radial site. Exploitation of relatively constant brachial transfer function enables the central aortic pressure wave to be synthesised from the radial pulse. This new clinical approach links traditional sphygmography (originally introduced in France) with conventional cuff sphygmomanometry, and is being evaluated in clinical and epidemiological studies.
O'Rourke
M F
MF
Medical Professorial Unit, St Vincent's Hospital, Darlinghurst NSW, Australia.
D000328:Adult; D000368:Aged; D000375:Aging; D001011:Aorta / Q000503:physiopathology; D001158:Arteries / Q000503:physiopathology*; D001696:Biomechanical Phenomena; D001916:Brachial Artery / Q000503:physiopathology; D002318:Cardiovascular Diseases / Q000209:etiology; D004548:Elasticity; D006801:Humans; D006973:Hypertension / Q000209:etiology; D008875:Middle Aged; D014652:Vascular Diseases / Q000150:complications / Q000503:physiopathology* / Q000628:therapy