Judith Swain, MD Bio
Gary F. Mitchell, MD Bio

Pulse Wave Velocity: A Risk Factor Whose Time Has Come

Assessing cardiovascular risk is important in primary prevention. We are able to provide individualized recommendations that are adjusted to individual cardiovascular risk and lifestyle preferences. Although we counsel all patients to manage risk factors such as cholesterol, BP, weight, exercise, and smoking, we double-down on those who are young and those at elevated risk.

The calculation of cardiovascular risk started in earnest with the results from the Framingham longitudinal cohort studies, and were further refined by a joint committee of the AHA and ACC1. The AHA/ACC ASCVD Risk Calculator that we carry on our smartphones takes into account sex, race, age, total cholesterol, HDL cholesterol, systolic BP, and whether an individual is on hypertensive medications, has diabetes, or smokes.

Since adoption of the AHA/ACC ASCVD Risk Score a number of additional risk factors have been proposed to further improve the calculation of risk. But how does one decide whether a risk factor should be incorporated into the CV risk calculation? According to an AHA Expert Panel2, a proposed risk factor should differ between subjects with and without outcomes; predict future outcomes; add predictive information on top of established risk markers; reclassify patients’ predicted risk to a sufficient extent, improve outcomes, and be cost efficient.

We now have an additional risk factor, carotid femoral pulse wave velocity (cfPWV), that fulfills the above criteria. In 2015 the AHA Council on Hypertension issued a statement3 that arterial stiffness provides incremental information beyond standard CVD risk factors in the prediction of future CVD events (Class IIa; Level of Evidence A), and that arterial stiffness can be determined by measuring cfPWV (Class I; Level of Evidence A). The statement concluded that measuring cfPWV provides novel and clinically relevant information beyond that provided by standard risk factors.

Using the current AHA/ACC Risk Factor Calculator a number of individuals fall into the intermediate-risk category, where we debate the pluses and minuses of additional diagnostic studies and of instituting more rigorous control of risk factors. Data demonstrate that around 13% of these intermediate risk individuals can be reclassified by the addition of cfPWV to the risk factor calculation4. In addition, a number of low-risk individuals, including younger adults, are up-classed when incorporating PWV into their CV Risk Score. For these two groups of individuals the measurement of PWV can indeed change their goals for risk factor control.

So why don’t we routinely measure PWV in our primary care clinics and cardiology practices? At present the measurement of cfPWV, although noninvasive, requires specialized equipment and trained personnel that are often only present in a hospital or large clinic setting. But that is changing as research and newer technologies are developed that can make measuring PWV almost as easy as obtaining weight and height. As these technologies enter the medical marketplace there will be little reason not to incorporate this important physiological measurement into our calculation of cardiovascular risk.

(Full references)
1. Goff DC, Lloyd-Jones, Bennett G, et al., 2013 ACC/AHA Guideline on the Assessment of Cardiovascular Risk: A Report of the American College of Cardiology/American Heart Association Task Force on Practice Guidelines. Circulation 2014 Jun 24;129(25 Suppl 2):S49-73

2. Hlatky MA, Greenland P, Arnett DK, et al., American Heart Association Expert Panel on Subclinical Atherosclerotic Diseases and Emerging Risk Factors and the Stroke Council. Criteria for evaluation
of novel markers of cardiovascular risk: a scientific statement from the American Heart Association. Circulation 2009;119:2408–16.

3. Townsend RR, Wilkinson IB, Schiffrin EL, Avolio AP, Chirinos JA,
Cockcroft JR, Heffernan KS, Lakatta EG, McEniery CM, Mitchell GF, Najjar SS, Nichols WW, Urbina EM, Weber T; on behalf of the American Heart Association Council on Hypertension. Recommendations for improving and standardizing vascular research on arterial stiffness: a scientific statement from
the American Heart Association. Hypertension. 2015;66:698-722.

4. Ben-Shlomo Y, Spears M, Boustred C, May M, Anderson SG, Benjamin
EJ, Boutouyrie P, Cameron J, Chen CH, Cruickshank JK, Hwang SJ,
Lakatta EG, Laurent S, Maldonado J, Mitchell GF, Najjar SS, Newman
AB, Ohishi M, Pannier B, Pereira T, Vasan RS, Shokawa T, Sutton-
Tyrell K, Verbeke F, Wang KL, Webb DJ, Willum Hansen T, Zoungas S,
McEniery C(1M, Cockcroft JR, Wilkinson IB. Aortic pulse wave velocity
improves cardiovascular event prediction: an individual participant metaanalysis
of prospective observational data from 17,635 subjects. J Am Coll
Cardiol. 2014;63:636–646.