Coronary atherosclerosis among Hong Kong Chinese--a histological and morphometric study using electronic digitizer

Prevalence of extracranial carotid and vertebral artery disease in Chinese patients with coronary artery disease

BACKGROUND AND PURPOSE

Chinese have been reported to have an extremely low prevalence rate of carotid and vertebral artery disease in comparison with whites. Previous studies, however, have been limited to general hospital stroke admission or postmortem series and were prone to selection bias. Extracranial cerebrovascular disease (ECCVD) is associated with coronary artery disease (CAD) in whites. Data associating ECCVD with CAD in Chinese patients are not available.

METHODS

We studied 153 consecutive Chinese patients with angiographically documented CAD. Duplex ultrasonography was performed to identify any underlying extracranial carotid and vertebral artery disease. Patient demographics; vascular risk factors; history of myocardial infarction, transient ischemic attack (TIA) or stroke; concomitant peripheral vascular disease (PVD); degree of left ventricular dysfunction; and extent and severity of CAD were also noted and analyzed.

RESULTS

Significant (> or = 50%) stenosis of one or more of the extracranial cerebral arteries was found in 32 patients (21%). The internal and external carotid arteries were involved in 17 of 153 patients (11%) and 19 of 153 patients (12%), respectively. The vertebral artery was involved in 9 of 153 patients (6%) and the common carotid artery in 3 of 153 (2%). Diabetes mellitus, hypertension, a history of TIA or stroke, and PVD were significantly associated with the presence of ECCVD.

CONCLUSIONS

Significant ECCVD is not uncommon in Chinese patients with CAD, and the prevalence is comparable with that reported in white populations. Patients with a history of diabetes, hypertension, TIA, stroke, and PVD are more likely to have concomitant ECCVD.

The effect of age on cardiovascular risk factors in Chinese women

Chinese women traditionally have a low incidence of coronary heart disease. However, information on cardiovascular risk factors in this population are relatively scarce. We examined these risk factors in 601 Hong Kong Chinese women (age+/-SEM, 38.5+/-0.4 years; range, 18-66 years) stratified into four age groups (group 1, < or =30 years; group 2, 31-40 years; group 3, 41-50 years; group 4, > or =51 years). Increasing age in Chinese women was associated with increased body mass index, waist-to-hip ratio, systolic and diastolic blood pressure, fasting plasma total cholesterol, triglyceride, low-density lipoprotein, apolipoprotein B, fasting and 2-h plasma glucose, glycated haemoglobin, fasting plasma insulin and urate concentrations. After adjustment for body mass index, waist-to-hip ratio and smoking, all these age-related associations remained statistically significant except for fasting plasma insulin concentration. There was a progressive increase with age in the prevalence of glucose intolerance, hypertension, dyslipidaemia and obesity. These prevalence rates further increased in subjects aged 51 years (the mean menopausal age in Asian women) or above. These findings suggest that age had an important and independent effect on cardiovascular risk in Chinese women and that, as in Caucasians, the onset of menopause might further increase this risk.

Pattern of cerebral atherosclerosis in Hong Kong Chinese. Severity in intracranial and extracranial vessels

BACKGROUND AND PURPOSE

The clinical pattern of stroke and the angiographic distribution of cerebral atherosclerosis in Chinese are different from those in Caucasians. Pathological data from autopsy studies are lacking.

METHODS

The intracranial and extracranial arteries supplying the brains of 114 consecutive Chinese patients undergoing autopsy in a regional general hospital were examined by computer-assisted morphometric analysis under a microscope as well as by macroscopic grading for atherosclerotic narrowing. The severity was correlated with various atherosclerosis-related factors.

RESULTS

Atherosclerosis of the intracranial cerebral vessels was more severe than that of the extracranial vessels. The distal branches of the intracranial vessels were also commonly involved. Hypertension and diabetes mellitus were identified as factors associated only with intracranial atherosclerosis (p < 0.001), whereas ischemic heart disease was associated with atherosclerosis in both the intracranial (p < 0.001) and extracranial (p = 0.012) vessels. Smoking was associated with narrowing of the extracranial vessels only (p = 0.0054).

CONCLUSIONS

Compared with figures from Caucasian and Japanese populations, the extent of intracranial atherosclerosis is much more severe in Hong Kong Chinese, whereas atherosclerotic narrowing of the extracranial carotid artery is less severe in Hong Kong Chinese than in Caucasians.

Coronary artery stenosis in an Australian population

The purpose of this study was to examine the extent and severity of coronary stenosis in an Australian population. The subjects were autopsy cases among people aged 20-69 yrs dying in and out of hospital in the Newcastle area of New South Wales in 1985-86. Three groups were compared: coronary deaths, deaths from other natural causes and deaths due to external causes. Cross-sectional luminal narrowing in each major subepicardial artery was measured by stereological point counting. Stenosis was found, as expected, to be more severe in males than in females, increased with age and was greatest in those who died from coronary disease. Even in non-coronary deaths mean percentage luminal narrowing in the narrowest segments ranged from about 40% in people aged 20-29 yrs to over 60% in those aged 60-69 yrs. Narrowing was more pronounced in the left anterior descending artery and least in the left circumflex artery. To the extent that results from this autopsy study can be generalized to the whole population, these findings illustrate that, despite declining mortality from ischemic heart disease in Australia, coronary atherosclerosis remains a widespread problem.

Morphometric analysis of coronary artery stenosis: an accuracy and reliability study

Luminal narrowing was assessed in 238 transverse segments obtained from coronary arteries removed at postmortem. In each segment, narrowing was assessed by gross visual estimation before and after fixation, and on histological sections by stereological point counting and computer-assisted planimetry. Computer-assisted planimetry was found to be accurate and reliable but the equipment needed is expensive, and requires specialized software and an experienced user. Morphometric measurement by stereologic point counting was accurate, rapid, simple, and inexpensive. In comparison with computer-assisted planimetry visual estimation was found to be neither accurate nor reliable. Our results indicate point counting as the method of choice for assessment of coronary artery luminal narrowing by atherosclerosis.

Coronary arterial dimensions and cell populations in ageing man

A combined computerised morphometric and immunocytochemical study on the ageing human coronary arterial wall shows that dilatation of the vessel is related to age but is less related to the degree of atherosclerosis. Loss of medial smooth muscle is not related to either atherosclerosis or dilatation of the artery. Occasional cases with severe medial and adventitial infiltrates of inflammatory cells (mainly T-cells and macrophages) do develop marked ectasia, but this arteritis is rather rare and, thus, an infrequent cause of dilatation.