Correlation of cardiac risk factors with carotid intima-media thickness and radial intima-media thickness measurements

Abstract

Introduction Early identification of patients at risk for future cardiovascular events is essential since addressing these early stages is more effective than treating advanced atherosclerotic vascular disease. The presence of multiple risk factors increases the development of atherosclerosis significantly. Stroke is the second most common cause of mortality and the third most common cause of disability. Globally, ultrasound has been the most common method of evaluating carotid atherosclerosis due to reasonably low-cost ultrasound tests, easy access to the carotid artery, and the fact that the equipment is readily available. Carotid intima-media thickness (CIMT) is an independent predictor for stroke, and CIMT is positively associated with the risk of stroke, cardiovascular disease, and coronary artery disease. Methods A prospective, descriptive-analytical single-centre study investigated the possible relationship between CIMT, radial intima-media thickness (RIMT), and modifiable and non-modifiable cardiac risk factors. This study was conducted at a private physician practice in Bloemfontein. Patients were referred from the Free State, Northern Cape, and Lesotho. The study sample included 250 1st time-visiting patients presenting with one or more modifiable cardiac risk factors. The following data was recorded, and examinations were performed: i) Demographic and anthropometric data: age (years), sex, ethnicity, geographic location, height(cm), weight(kg), and body mass index (BMI) (kg/m²). ii) Clinical data: modifiable and non-modifiable risk factors and family history. iii) Ultrasound data: carotid and radial intimal medial thickness were recorded for each patient that consented to participate in the study. iv) Other clinical data recorded from the patient's medical file included: human immunodeficiency virus (HIV) status and rheumatoid arthritis (RA). Results As expected, most patients came from the Free State (97.2%) and only 2.8% from other provinces. Most of these patients resided in the Mangaung Metropolitan district (85.6%). The mean age of patients was 60.2 years, with a female predominance (63.6% vs 36.4%); most patients were Caucasian (76%). In the total study population, 42% (n=104) of patients presented with three or more modifiable risk factors, 39% (n=98) with two, and 48 patients (19%) with only one modifiable risk factor. Hypertension was the most common modifiable risk factor (89%), followed by obesity (66%). Diabetes Mellitus (DM) was present in 30% of patients, of which 55% presented with DM type 1 and 45% with DM type 2. The mean CIMT of the total group was 0.8±0.2 mm, and the maximum CIMT was 1.9 mm (right carotid artery) and 1.7 mm (left carotid artery). In men, the mean CIMT was 0.9±0.2 mm, and in women, 0.8±0.3 mm. Twenty-four percent of the study population presented with a stroke, and 51% of patients diagnosed with stroke or transient ischemic accident (TIA) had an abnormal CIMT. An abnormally thickened CIMT (≥0.9 mm) was observed in 107 (43%) of the study population with a mean of 1.1 mm±0.15. Discussion Age and male sex were the only non-modifiable risk factors contributing to the risk of an increase in mean CIMT: each year of age added 11% to the risk of having a thickened CIMT. Apart from demonstrating a risk for thicker CIMTs, significantly more men had an abnormal CIMT compared to the normal CIMT group indicating male sex as a significant risk factor. Our results show that individual risk factors played a role in thickened CIMT. Hypertension, DM, hypercholesterolemia, and smoking significantly contributed to a thickened CIMT, whereas only hypercholesterolemia was associated with a thickened RIMT. Risk factor combinations like DM and hypertension and hypertension and smoking significantly increase the risk of having thicker CIMT measurements. In contrast, the only combination associated with a significant contribution to a thicker mean RIMT was hypertension and obesity. The odds ratios of the combinations were markedly higher than isolated risk factors, most likely indicating the summative effects when individual risk factors occur in combination. However, it appears that having hypercholesterolemia and DM or hypercholesterolemia and obesity reduces the risk of having a thickened CIMT. The authors speculate that many of these patients were on statin treatment which may lend protection against an increased CIMT. Conclusion In conclusion, this study shows that male sex, increased age, hypertension, DM, hypercholesterolemia, and smoking significantly contributed to a thickened CIMT, whereas only hypercholesterolemia was associated with a thickened RIMT. Among all risk factors, hypertension had the most significant impact on the mean CIMT compared to the other modifiable risk factors. Risk factor combinations were also associated with a thickened CIMT and RIMT, and combinations appeared to add to the summative risk.