Carotid Doppler Indices With Age and Body Mass Index in a Sampled Nigerian Population

Abstract

Background: Carotid Doppler studies are frequently carried out to assess for possible stenosis resulting from the presence of carotid plaques. The carotid peak systolic velocity (PSV) and end-diastolic velocity (EDV) are key indices for determining the severity of the stenosis. However, normative values of these parameters may be dependent on anthropological variables like age and body mass index (BMI) Objective: The study was aimed at assessing the variations of PSV and EDV with age and BMI in a sampled Nigerian population. Materials and Methods: A total of 204 participants (72 males and 132 non-gravid females) aged between 20 and 70 years who were normotensive with no cardiovascular diseases were selected. Their ages, BMI, PSV and the EDV were measured using standard protocols for the four segments of the carotid artery: common carotid (CC), carotid bulb (CB), internal carotid (IC) and the external carotid (EC). Data obtained were presented using tables and line graphs while the analysis of variance (ANOVA) was used to determine the significant differences in measurement across the groups. Results: The mean PSV recorded were 88.25 ± 7.43 cm/s for the CC, 73.93 ± 6.23 cm/s for the IC, 51.01 ± 4.30 cm/s for the CB and 50.41 ± 4.25 cm/s for the EC. There was a steady increase of the PSV between 20 and 46 years from 74.91 cm/s to 98.78 cm/s for the CC, from 62.76 cm/s to 82.75 cm/s for the IC, from 42.80 cm/s to 56.43 cm/s for the EC and from 43.30 cm/s to 57.10 cm/s for the CB. The maximum EDV measured for the IC was (24.75 ± 2.11 cm/s). Others were 21.12 ± 1.8 cm/s for the CC, 19.38 ± 1.65 cm/s for CB and 16.92 ± 1.44 cm/s for the EC. The EDV also increased steadily between 20 to 46 years from 17.76 cm/s to 23.68 cm/s for the CC, from 21.04 cm/s to 27.75 cm/s for the IC, from 14.38 cm/s to 18.97 cm/s for the EC and from 16.48 cm/s to 21.73 cm/s for the CB. The PSV and EDV varied significantly with age (p > 0.05). Also, the PSV and EDV increased slightly with increasing BMI from 30 – 31.9 kg/m2. For a BMI of 20 kg/m2 to 32 kg/m2, the increase in PSV were from 79.48 cm/s to 90.75 cm/s for the CC, from 66.58 cm/s to 76.03 cm/s for the IC, from 45.40 cm/s to 51.85 cm/s for the EC and from 45.94 cm/s to 52.46 cm/s for the CV. Similarly, the PSV and EDV values decreased at a BMI of 30 – 31.99 kg/m2. Thus, the BMI was significantly associated with PSV and EDV across all segments of the carotid artery (p > 0.05). Conclusion: There are significant variations in carotid PSV and EDV with age and BMI. These variations should be taken into consideration when diagnoses on alterations in carotid artery flow are to be made using PSV and EDV values.