Ascending aortic pressure wave indices and cardiovascular disease.

T he study by Jankowski et al (p 641) confirms that in yet another country (Poland) the indices of the aortic pressure waveform are related to clinical cardiovascular disease. Other data come from both direct and indirect measures of aortic or central (carotid) pressure, from healthy subjects, patients with coronary artery disease, hypertension, and renal failure, and from populations in China, Japan, France, Austria, Germany, and Australia (Table 1). These results are in accordance with some large studies on brachial pulse pressure, but not other studies. Those large studies, which show a poor relationship between brachial pulse pressure and cardiovascular events, have been criticized on the basis of systematic errors in pressure measurement, which are magnified in a measure (pulse pressure) that includes errors from measurement of cuff systolic pressure and of cuff diastolic pressure. In the study by Jankowski et al and other studies (Table 1), relatively small numbers of patients showed a relationship between cardiovascular disease and pressure measurements in the aorta but not pressure measurements in the brachial artery. This indicates that measures of central pressure are more directly related to cardiovascular events in central arteries than measures of pressure in a peripheral artery. This is what one would expect from general principles. Reasons for greater importance of central compared to peripheral pressure have been emphasized by Safar et al, and include the errors inherent in measurements of cuff pressure as described by Jankowski et al (their reference 8). Many of those involved in this work have successfully avoided sphygmomanometric cuff errors by relating events to measures such as aortic pressure augmentation index, aortic pulse wave velocity, and amplification of the pulse waveform between the central aorta and brachial artery (Table 1). All of these can be determined from noninvasive measurement of the central pressure waveform by applanation tonometry, as well as invasive measurements at cardiac catheterization. They are independent of cuff calibration.