Association between a novel ultrasound-based measure of plaque burden and cardiovascular risk: the P-SONAR study

Ultrasound-based assessment of subclinical atherosclerosis improves cardiovascular (CV) risk prediction, but methods to quantify plaque burden vary. We developed a novel method to measure plaque burden entitled weighted total plaque thickness (wTPT) and evaluated its association with CV risk factors and estimated CV risk.

A total of 5,180 participants (age 45-74 years; 54.2% women) from the Prospective Screening Of Non-invasive Atherosclerosis Risk study, all self-referred for a health check, underwent carotid and femoral ultrasound. Plaque burden was quantified using wTPT, maximal plaque thickness (MPT), plaque count, and number of arteries with plaque. CV risk was estimated using the standardized NORRISK-2 equation.

Prevalence of carotid, femoral, and any plaque was 90.2%, 79.7%, and 96.1%, respectively. Femoral wTPT was significantly higher than carotid wTPT (P<0.001). In multivariable analysis, all CV risk factors except abdominal obesity were independently associated with wTPT. Spearman's correlation between wTPT and CV risk was 0.66 [95% confidence interval (CI): 0.66-0.68], exceeding that of MPT [0.61 (95% CI: 0.59-0.63)], plaque count [0.62 (95% CI: 0.59-0.65)], and number of arteries with plaque [0.59 (95% CI: 0.58-0.62)]. Femoral wTPT showed a stronger correlation with CV risk [0.59 (95% CI: 0.57-0.61)] than carotid wTPT [0.55 (95% CI: 0.53-0.57)].

In this asymptomatic cohort, plaque was present in nearly all individuals, underscoring the importance of stratifying plaque burden rather than prevalence. wTPT demonstrated a stronger association with estimated CV risk than conventional plaque measures, with femoral burden more closely linked to risk than carotid burden.