Aortic pulse wave velocity and HeartSCORE: improving cardiovascular risk stratification. a sub-analysis of the EDIVA (Estudo de DIstensibilidade VAscular) project

HeartSCORE is a tool for assessing cardiovascular risk, basing its estimates on the relative weight of conventional cardiovascular risk factors. However, new markers of cardiovascular risk have been identified, such as aortic pulse wave velocity (PWV). The purpose of this study was to evaluate to what extent the incorporation of PWV in HeartSCORE increases its discriminative power of major cardiovascular events (MACE).

This study is a sub-analysis of the EDIVA project, which is a prospective cohort, multicenter and observational study involving 2200 individuals of Portuguese nationality (1290 men and 910 women) aged between 18 and 91 years (mean 46.33 ± 13.76 years), with annual measurements of PWV (Complior). Only participants above 35 years old were included in the present re-analysis, resulting in a population of 1709 participants. All MACE - death, cerebrovascular accident, coronary accidents (coronary heart disease), peripheral arterial disease and renal failure - were recorded. During a mean follow-up period of 21.42 ± 10.76 months, there were 47 non-fatal MACE (2.1% of the sample). Cardiovascular risk was estimated in all patients based on the HeartSCORE risk factors. For the analysis, the refitted HeartSCORE and PWV were divided into three risk categories. The event-free survival at 2 years was 98.6%, 98.0% and 96.1%, respectively in the low-, intermediate- and high-risk categories of HeartSCORE (log-rank p < 0.001). The multi-adjusted hazard ratio (HR) per 1 - standard deviation (SD) of MACE was 1.86 (95% CI 1.37-2.53, p < 0.001) for PWV. The risk of MACE by tertiles of PWV and risk categories of the HeartSCORE increased linearly, and the risk was particularly more pronounced in the highest tertile of PWV for any category of the HeartSCORE, demonstrating an improvement in the prediction of cardiovascular risk. It was clearly depicted a high discriminative capacity of PWV even in groups of apparent intermediate cardiovascular risk. Measures of model fit, discrimination and calibration revealed an improvement in risk classification when PWV was added to the risk-factor model. The C statistics improved from 0.69 to 0.78 (adding PWV, p = 0.005). The net reclassification improvement (NRI) and integrated discrimination improvement (IDI) were also determined, and indicated further evidence of improvements in discrimination of the outcome when including PWV in the risk-factor model (NRI = 0.265; IDI = 0.012).

The results clearly illustrate the benefits of integrating PWV in the risk assessment strategies, as advocated by HeartSCORE, insofar as it contributes to a better discriminative capacity of global cardiovascular risk, particularly in individuals with low or moderate cardiovascular risk.