Ahead of the curve: waveform analysis of blood pressure, reflection magnitude, and outcomes.

The history of blood pressure (BP) waveform analysis is almost as undulatory as the waveform itself. The development of the sphygmograph in the mid-19th century led to a relatively brief, albeit intense, interest in the interpretation of the BP waveform. This was perhaps more an art than a science, and interest in the sphygmograph and the waveform declined after the introduction of the cuff-based sphygmomanometer. More recently, interest in pulse waveform analysis has reemerged, and the relative merits of estimated aortic (central) as opposed to brachial systolic and pulse pressure have been widely discussed. Although some issues remain unresolved, evidence from systematic reviews suggests that central pulse pressure may be a better predictor of cardiovascular events and that central BP can be differentially modified by antihypertensive therapy, with β-blockers being comparatively less effective on central than peripheral BP. However, whatever the merits of measurement of central systolic or pulse pressure, a single number is unlikely to be an adequate descriptor of the morphology of a waveform, and the waveform may contain additional valuable and quantifiable information. In this issue, Zamani et al report the results from ≈6000 participants in the Multi-Ethnic Study of Atherosclerosis (MESA). BP waveforms were recorded using a noninvasive radial tonometric device and analyzed using a technique that separates them into forward (P f ) and backward (P b ) components. Reflection magnitude (RM) was calculated as the ratio of peak P b /peak P f . RM and P b were found to predict all-cause mortality, cardiovascular mortality, and noncardiovascular mortality in unadjusted models. Notably, the association with all-cause mortality was independent of conventional risk factors. It is also of interest, in terms of mechanisms, that this association was independent of a wide range of measures of subclinical atherosclerosis. These findings extend previous data from MESA where RM predicted cardiovascular end points and was strongly predictive of new-onset chronic heart failure. Associations between