Increased carotid intima-media thickness in hypertensive patients is caused by increased medial thickness / 대한내과학회지

BACKGROUNDS/AIMS: It has been suggested that there is a differential response of the vasculature to systemic risk factors for atherosclerosis. We sought to evaluate the impact of hypertension on the carotid arterial wall using new methods that can measure each arterial wall layer. METHODS: The study subjects consisted of 163 patients who underwent carotid arterial scanning using high-resolution ultrasound that could measure the left carotid intima-media, intima, and media separately. The individual carotid arterial wall thickness was measured off-line by a new method using the Canny edge-detection algorithm. RESULTS: Hypertensive patients (n=79, mean age 61.8 years) had a higher prevalence of diabetes (31.6% vs 11.9%, p=0.004) and a lower level of HDL-cholesterol than did normotensive patients (41.8+/-11.0 mg/dL vs 45.7+/-10.0 mg/dL, p=0.019). Hypertensive patients had higher carotid intima-media thickness (CIMT, 0.81+/-0.21 mm vs 0.74+/-0.18 mm, p=0.003) and carotid medial thickness (CMT, 0.46+/-0.12 mm vs 0.42+/-0.09 mm, p=0.007) than did normotensive patients, whereas carotid intimal thickness (CIT) was not significantly different (0.34+/-0.04 mm vs 0.34+/-0.04 mm, p=0.196). Multivariate analysis revealed that the independent factors of CIMT were CMT (beta=0.915, p<0.001), hypertension (beta=0.076, p=0.008), age (beta=0.074, p=0.010), and sex (beta=-0.079, p=0.005). Pearson correlation coefficient between CIMT and CMT was higher (r=0.932, p<0.001 vs r=0.445, p<0.001) than that between CIMT and CIT. The correlation between CIMT and CMT was higher (r=0.940, p<0.001 vs r=0.910, p<0.001) in hypertensive patients than in normotensive patients, whereas that between CIMT and CIT was lower (r=0.344, p=0.002 vs r=0.583, p<0.001) in hypertensive patients. CONCLUSIONS: The increased CIMT is caused by increased CMT in hypertensive patients, and this finding is compatible with the medial hypertrophy seen in hypertension. The carotid medial layer should be the focus of attention in future studies looking at hypertensive patients.

The Serum Lipid Level is Associated with Intimal Thickness of the Carotid Artery for Patients with Coronary Atherosclerosis

BACKGROUND AND OBJECTIVES: It's not clear whether the serum lipid level is associated with the individual carotid arterial wall thickness for patients suffering with coronary atherosclerosis, although hypercholesterolemia is associated with an increased carotid IMT. We sought to evaluate the association between the serum lipid level and the individual carotid arterial wall thickness (intimal thickness (IT) and medial thickness (MT)) as well as the carotid intima-media thickness (IMT) for patients with coronary atherosclerosis. SUBJECTS AND METHODS: The carotid arterial wall thickness was measured using high-resolution B-mode ultrasound in 139 consecutive patients (58+/-11 years old, 75 males) with coronary atherosclerosis by performing coronary angiography. RESULTS: Measurement of the individual arterial wall thickness was possible in 126 patients (90.6%) out of all the study subjects. The carotid IMT was correlated with the total cholesterol (r=0.207, p=0.015) and low-density lipoprotein (LDL) cholesterol (r=0.237, p=0.006). The carotid IT was correlated with the total cholesterol (r=0.210, p=0.020), triglyceride (r=0.212, p=0.018), and LDL-cholesterol (r=0.246, p=0.006), whereas the MT did not show any significant correlation with the serum lipid level. Multivariate analysis disclosed that the serum LDL cholesterol level was associated with the carotid IMT and IT for the patients with coronary atherosclerosis, but it was not correlated with the MT. CONCLUSION: This study suggests that the serum LDL cholesterol level is more closely associated with the carotid IT than the IMT for patients with coronary atherosclerosis, and each carotid arterial wall has a different response to the serum lipid level.

Carotid Intima Media Thickness is Associated with the Framingham Risk Score in Korean Patients with Coronary Arteriosclerosis: Association between IMT and Framingham Risk Score

BACKGROUND AND OBJECTIVES: Carotid intima media thickness (IMT) is associated with an increased risk of cardiovascular events whereas the Framingham risk score (FRS) is globally used to evaluate cardiovascular risk. We sought to evaluate the relationship between carotid IMT and FRS in Korean patients with coronary arteriosclerosis. SUBJECTS AND METHODS: The study population consisted of angiographically proven 267 consecutive patients with coronary arteriosclerosis (mean age 59 years, 141 males). Carotid IMT was measured by high-resolution ultrasound and semiautomatic methods. The FRS was derived from the algorithm published in the National Cholesterol Education Program Adult Treatment Panel III guidelines (NCEP-ATP III) using age, gender, smoking, systolic blood pressure level, use of antihypertensive treatment and total and high-density lipoprotein cholesterol levels. RESULTS: Carotid IMT correlated with the FRS in men (r=0.307, p<0.001) and in women (r=0.429, p<0.001). The severity of CAD, which was graded on the number of stenosed major coronary arteries more than 50%, showed a significant positive correlation with the FRS (r=0.266, p<0.001) and carotid IMT (r=0.166, p=0.007). The mean value of the FRS in patients with carotid plaque was higher than in patients without carotid plaque (15.0+/-3.9 and 12.0+/-4.4, p<0.001). The FRS was independently associated with carotid IMT in men and women (beta=6.433, p=0.001 and beta=11.271, p<0.001, respectively). CONCLUSION: The FRS for primary prevention was significantly associated with carotid IMT even in patients with CAD and also a correlation with the severity of CAD. The FRS may be helpful to predict the prognosis in patients with coronary arteriosclerosis such as carotid IMT and a prospective cohort study may be required to certify the usefulness of the FRS.

Measurements of Carotid Intima, Media, and Intima-media Thickness and Their Clinical Importance / 의학물리

The severity of carotid intima-media thickness (IMT) is an independent predictor of atherosclerosis which causes transient cerebral ischemia, stroke, and coronary events such as myocardial infarction. The IMT consists of intima thickness (IT) and media thickness (MT). However, the Individual clinical significance of IT and MT has not been well studied. We devised a method of measuring IT, MT, and IMT using B-mode ultrasound image processing technique for the diagnosis of atherosclerosis. To inspect the clinical significance of IT, MT, and IMT, one hundred forty-four consecutive patients (mean age; 57 years old, 72 males) were underwent common carotid artery scanning using high-resolution ultrasound. Results showed that, the IT (p<0.05), MT (p<0.05) as well as IMT (p<0.01) of patients with atherosclerotic disease were significantly thicker than that of the patients without atherosclerotic disease. Patients with hypertension showed significantly thicker IT (p<0.01), MT (p<0.001), and IMT (p<0.001). However, only IT was thicker in patients with smoking (p<0.01). The IT (r=0.374, p=0.001), MT (r=0.433, p=0.000), and IMT (r=0.479, p=0.000) showed positive correlation with age. The coefficients of determination (r(2)) were estimated to be 92.4% for IMT and MT, 49.1% for IMT and IT, and 27.4% for IT and MT. This result suggests that the intima layer of the carotid artery has a different physiology with the media layer.

Measurement of the Carotid Intima, Media and Intima-Media Thickness with Ultrasound and New Software

BACKGROUND AND OBJECTIVES: We performed this study to evaluate the feasibility and accuracy of the newly developed Korean software (KS) for measurement of the carotid intima-media thickness (IMT), which was compared with the commercial software. SUBJECTS AND METHODS: The study population consisted of 60 consecutive patients (mean of 59 years old, 27 males) undergoing transthoracic echocardiography. We measured the carotid IMT using both software packages, and also measured the intima thickness (IT) and media thickness (MT), separately, using the KS package. RESULTS: Measurement of the IMT was possible in all the study subjects with both software packages, but the separate measurements of the IT and MT was possible in only 24 patients using the KS package. The mean IMT using the commercial and KS packages were 0.727+/-0.157 and 0.733+/-0.156 mm, respectively, which were found to correlate (r=0.985, p=0.000). The mean IMT, IT and MT of the 24 patients were 0.841+/-0.138, 0.340+/-0.033 and 0.505+/-0.124 mm, respectively. The carotid IMT was correlated with the IT and MT and also with the IT/IMT, MT/IMT and IT/MT ratios (r=0.562, p=0.004; r=0.934, p=0.000; r=-0.809, p=0.000; r=0.591, p=0.002; r=-0.754, p=0.000, respectively). The IT was found not to correlate with the MT (r=0.369, p=0.076). Age was found to correlate with the IMT using both the commercial and KS packages (r=0.616, p=0.000; r=0.583, p=0.000, respectively), and with the MT and IT/IMT and IT/MT ratios (r=0.504, p=0.012; r=-0.538, p=0.007; r=-0.428, p=0.037), but not with the IT (r=0.300, p=0.154). CONCLUSION: The newly developed KS was feasible and accurate in measuring the carotid IMT, which can also be used to separately measure the IT and MT.