Ultrasonic backscatter of the carotid wall in young and older athletes.

OBJECTIVES The aim of this study was to evaluate the effects of habitual exercise on the age-related changes of carotid wall composition defining its acoustic reflectivity by the quantitative approach of integrated backscatter (IBS) analysis. DESIGN Cross-sectional study. SETTING University Hospital. SUBJECTS Fifty-four competitive long-distance runners (males, age range 22-72 years) and 50 healthy sedentary controls. MAIN OUTCOME MEASURES All the subjects underwent both 2-D conventional ultrasonography and IBS analysis. IBS values were sampled from a region of interest (ROI) placed within five consecutive regions of the common carotid intima-media, and then corrected (C-IBS) for the IBS value of the adventitia. RESULTS Athletes showed a lower C-IBS (-27.07 +/- 2.9 dB vs. -24.57 +/- 4 dB, P < 0.0001) and a smaller intima-media thickness (IMT: 0.64 +/- 0.16 mm vs. 0.78 +/- 0.21 mm, P < 0.001) respect to sedentary controls. By selecting the lowest (<30 years of age) and the highest (>60 years of age) tertile of age, we assess the influence of age on IMT and IBS. Sedentary older individuals exhibited an IMT higher respect to young controls and to the both trained subgroups (P < 0.0001). C-IBS was lower in both subgroups of athletes, independently of age, and lower in sedentary young people respect to sedentary older subgroup (P < 0.0001). Endurance chronic exercise blunted the difference of C-IBS observed between young and older sedentary individuals. Moreover, C-IBS was positively related to age (r = 0.77, P < 0.0001) and IMT (r = 0.52, P < 0.0001). CONCLUSIONS The age-related changes of the arterial wall are attenuated by physical training. These modifications can be quantitatively discriminated by ultrasonic backscatter method.