Nonstenotic internal carotid arteries: Effects of age and blood pressure at the time of scanning on Doppler US velocity measurements

PURPOSE: To assess the effects of age and blood pressure at the time of sca nning on internal carotid artery velocities and cross-sectional diameter at Doppler ultrasonography(US). MATERIALS AND METHODS: During 12 months, 1,020 consecutive patients underwe nt internal carotid artery Doppler US. No or minimal arterial disease was f ound in 142 patients (67 women, 75 men). Blood pressure was recorded prior to examination. The angle-corrected internal carotid artery peak systolic a nd end-diastolic velocities were obtained. The effects of systolic blood pr essure, diastolic blood pressure, pulse pressure, age, chronic hypertension , and medications for hypertension on velocities were evaluated by using li near regression analysis. RESULTS: Peak systolic velocity was influenced by age (P = .008), systolic blood pressure (P = .009), diastolic blood pressure (P = .003), and pulse p ressure (P = .017) but not history of hypertension (P = .53) or antihyperte nsive medication use (P = .77). Increasing age decreased peak systolic velo city by 0.34 cm/sec/y. End-diastolic velocity was influenced by age (P < .0 01) but not by systolic, diastolic, or pulse pressure (all P values were > .13). CONCLUSION: Internal carotid artery peak systolic velocities decrease with advancing age and increase with increasing pulse pressure. The effects of b lood pressure at the time of scanning are small, but isolated systolic hype rtension could cause increases in spurious velocity.