Brachial-ankle pulse wave velocity as a marker of adverse events following non-ST-elevation myocardial infarction: a new standard in risk stratification?
The prognostic value of arterial stiffness has been of recent interest as a risk predictor of cardiovascular disease 7,8. Arterial stiffness of the vascular wall progresses with aging 9 as well as comorbidities such as diabetes and hypertension 10. This in turn is a major determinant of systolic blood pressure, left ventricular load, and myocardial oxygen requirements 10. Although surrogate measurements of arterial wall stiffness have been developed 11, many have not been integrated into clinical practice because of the inconvenience associated with the measuring devices 12, thus relegating them to research purposes alone.
However, in 2000, the brachial-ankle pulse wave velocity (baPWV) measurement was introduced, developed by scientists in Japan 13,14. baPWV is measured using a volume-plethysmographic apparatus that estimates the pulse wave of the brachial artery and the ankle through the use of blood pressure cuffs on all four limbs. The distance between the upper arm and the ankle is then calculated using linear regression of body height, with increasing values representing increasing lower limb arterial stiffness. baPWV assesses the systemic arterial stiffness index through a device that has improved usability, thus enabling easier adoption and incorporation into routine practice 12. In fact, more than 10 000 devices are currently used in clinical practice in Japan alone 14.
Since development, greater than 850 scientific papers have been published assessing the clinical significance of elevated baPWV, primarily within the Eastern Asian countries of Japan, China, and Korea 12,14. Increasing baPWV has been correlative with conditions ranging from hypertension to decreased renal function and the use of baPWV as an assessment of subclinical target organ damage is currently included in Japanese guidelines for the management of hypertension 14.
Some of the strongest data on baPWV have involved its association with future cardiovascular events 15,16. For instance, in an analysis of Japanese individuals with untreated hypertension, patients with elevated baPWV were found to have a 2.8-fold increased risk of subsequent cardiovascular events 17. In addition, a meta-analysis of 18 studies involving 8169 participants showed that an increase in baPWV measurements by 1 m/s corresponded with an increase of 12%, 13%, and 6% in total cardiovascular events, cardiovascular mortality, and all-cause mortality, respectively 16.
In the current analysis by Park et al. 18, the authors assessed whether an association between baPWV and adverse cardiovascular events exists among a less commonly studied population – patients presenting with non-ST-elevation myocardial infarction (NSTEMI). As the authors reference, to date, there have been surprisingly few studies evaluating the prognostic value of elevated baPWV in patients with acute coronary syndromes 19. As such, the authors leveraged a unique population of 411 patients who presented with NSTEMI and received a percutaneous coronary intervention at a single center in Korea to investigate this relationship. The authors found that patients with a baseline baPWV measurement of more than 1708 cm/s experienced greater major adverse cardiovascular events and cardiac mortality at 350 days compared with those with lesser values. In addition, after adjustment for potential confounders, elevated baPWV corresponded with a 3.