Rapid Screening for Subclinical Atherosclerosis by Carotid Ultrasound Examination: The HAPPY (Heart Attack Prevention Program for You) Substudy.

BACKGROUND

Cardiovascular disease (CVD)-related death rates have been escalating in emerging economies such as India. A strategy to initiate prophylactic medical intervention by direct identification of subclinical atherosclerotic burden may be appropriate in rural populations where assessment based on traditional risk factors is not available.

OBJECTIVES

This study sought to investigate the feasibility of performing rapid automated carotid ultrasound studies in a rural setting and to measure the prevalence of carotid plaques and age-specific distribution of carotid intima-media thickness (IMT) as an index of subclinical atherosclerosis.

METHODS

Screening of the extracranial carotid system with automated B-mode ultrasound was performed along with health questionnaire assessments in 771 asymptomatic volunteers (ages 40 ± 14 years; 626 men and 145 women) with no known CVD. Measurements of IMT were recorded as the mean of 24 spatial measurements performed over a 1-cm region in the far wall of the common carotid artery at end diastole; the prevalence of the plaque (focal IMT >1.5 mm) was determined.

RESULTS

A total of 69 (8.9%) subjects had atherosclerotic plaques. Of these, 16 (2.1%) exhibited bilateral plaques, 28 (3.6%) left carotid plaque only, and 25 (3.2%) had right carotid plaques. Patients even under 50 years showed a high prevalence of carotid plaques (7%), which increased with age (25% and 35% for 51 to 70 and >70 years, respectively). Only 3 (4.3%) participants with plaques were former smokers. Global mean IMT was 0.55 ± 0.13 mm and correlated with age for both left and right carotid arteries (r = 0.61 and 0.60, p < 0.001 for both) in male as well as female subjects (r = 0.70 and 0.67, p < 0.001 for both), respectively.

CONCLUSIONS

Rapid community screening for subclinical atherosclerosis is feasible with automated carotid ultrasound examination and may be beneficial in rural communities of industrializing nations where traditional CVD risk factor data are not yet readily available.