Relation of Serum Total Cholesterol and Other Risk Factors to Risk of Coronary Events in Middle-Aged and Elderly Japanese Men With Hypercholesterolemia-The Kyushu Lipid Intervention Study-

Hypercholesterolaemia and risk of coronary heart disease in the elderly: impact of age: the Copenhagen City Heart Study

BACKGROUND

Population and interventional studies have shown that high plasma-cholesterol is a risk factor of coronary heart disease (CHD). However, in most of the studies elderly people were excluded.

AIM

This paper assesses whether the effect of total plasma-cholesterol on the risk of incident CHD decreases with age in a healthy population.

METHODS

Within the Copenhagen City Heart Study in 1981-1983, 4647 men and 5829 women, aged 40-93 years, underwent a cardiovascular health examination including measurement of plasma-cholesterol. The cohort was followed with respect to incident CHD until 1994, i.e. before statins were introduced in Denmark.

RESULTS

In people below 60 years of age plasma-cholesterol levels on 5-6; 6-8; and >8 mmol/L were associated with relative risks of CHD on 2.0 (95% confidence interval (CI) 1.2-3.2, P=0.004); 3.1 (CI 2.0-5.0, P<0.001); and 5.1 (CI 2.8-9.3, P<0.001), respectively (reference group: plasma-cholesterol <5 mmol/L). In people aged 60-70 years a plasma-cholesterol level on 5-6 mmol/L was not associated with increased risk, whereas plasma-cholesterol on 6-8 mmol/L and >8 mmol/L was associated with relative risks on 1.3 (CI 1.0-1.8, P=0.03), and 2.3 (CI 1.6-3.4, P<0.001), respectively. In people aged 70-80 years only plasma-cholesterol >8 mmol/L conferred increased relative risk on 1.6 (CI 1.2-2.4, P=0.007). In people above 80 years of age increased plasma-cholesterol was not associated with increased risk of incident CHD.

CONCLUSION

The risk of incident CHD associated with high plasma-cholesterol declines with age. This finding should be considered in future recommendations of plasma-cholesterol levels in elderly people without atherosclerotic cardiovascular disease.

Gender difference in coronary events in relation to risk factors in Japanese hypercholesterolemic patients treated with low-dose simvastatin

BACKGROUND

Gender differences between the risk factors for coronary heart disease and coronary events were examined in the Japan Lipid Intervention Trial, a 6-year observational study.

METHODS AND RESULTS

Men (12,575) and women (27,013) were analyzed for risk of coronary events (acute myocardial infarction and sudden cardiac death). Simvastatin reduced serum low-density lipoprotein cholesterol (LDL-C) by 27% in both genders, and increased serum high-density lipoprotein cholesterol (HDL-C) in men (5%) and women (4%). The incidence of coronary events was lower in women (0.64/1,000 patient-years) than in men (1.57/1,000 patient-years). The risk of coronary events increased by 18% in men and 21% in women with each 10 mg/dl elevation of LDL-C, and decreased by 39% in men and 33% in women with each 10 mg/dl elevation of HDL-C. The risk increased proportionally with aging in women, but not in men. Diabetes mellitus (DM) was more strongly related to the risk of coronary events for women (relative risk 3.07) than for men (relative risk 1.58).

CONCLUSIONS

The incidence of coronary events is lower in women. Serum LDL-C is related to an increased risk of coronary events to the same extent in both genders. DM seems to be a more important risk factor in women, trading off the lower risk of coronary events among them.

Treatment of Hyperlipidemia from Japanese Evidence

The treatment of hyperlipidemia is aimed at preventing cardiovascular disease (CVD) and coronary heart disease (CHD). As the incidence of CHD in Japan is about one-third lower and that of stroke is two-fold higher compared to Western countries, and the doses of lipid-lowering drugs used in foreign randomized controlled clinical trials (RCTs) are much higher than in general use in Japan, it remains unclear whether the results of RCTs conducted in Western countries could be extrapolated to Japanese patients. Recently, two major large-scale, prospective, RCTs in Japanese hypercholesterolmic patients, the Management of Elevated Cholesterol in the Primary Prevention of Adult Japanese (MEGA) study and the Japan EPA Lipid Intervention Study (JELIS), have been reported. Japanese epidemiological studies and Japanese clinical studies are reviewed. The evidence suggests that hypercholesterolemia, hypertriglyceridemia, and low HDL-cholesterol are strongly associated with increased CHD risk. Lipid-lowering medication shows beneficial effects even in low-risk populations; however, the data did not support that lower cholesterol is better. The safety and efficacy of hyperlipidemia treatment in Japanese patients are discussed.

Cigarette Smoking Induced Oxidative Stress may Impair Endothelial Function and Coronary Blood Flow in Angiographically Normal Coronary Arteries

BACKGROUND

Smoking contributes to the progression of atherosclerotic heart disease by causing endothelial dysfunction. In the present study the effect of smoking on endothelial functions and coronary flow was investigated, as well as the relationship of these factors with oxidative stress parameters, in subjects with normal coronary arteries.

MATERIALS AND RESULTS

The study group comprised 87 patients with angiographically normal coronary arteries (36 smokers, 51 nonsmokers). Coronary flow patterns were determined by the Thrombolysis In Myocardial Infarction (TIMI) frame count method. Endothelial function was evaluated by high-frequency ultrasound imaging of the brachial artery. Superoxide dismutase (SOD) and reduced glutathione (GSH) and reduction of oxidative material in the body and the endproduct of lipid peroxidation, malondialdehyde (MDA), were measured as oxidative stress markers. Mean TIMI frame count was significantly higher in smokers than nonsmokers (42.2 +/- 16 vs 29.5 +/- 9.5, p = 0.0001). Endothelium-dependent flow-mediated dilatation was 6.81+/-1.95% in nonsmokers and 5.7 +/- 2.2% in smokers (p = 0.0001). The smokers had dramatically higher levels of SOD and MDA and lower levels of GSH than the nonsmoker group.

CONCLUSION

Smoking induced oxidative stress deteriorates coronary blood flow by disturbing endothelial function.

Relation of serum total cholesterol and other factors to risk of cerebral infarction in Japanese men with hypercholesterolemia

BACKGROUND

Risk factors for cerebral infarction have not been well clarified, except for hypertension (HT), and few studies have examined the risk factors in the elderly.

METHODS AND RESULTS

Clinical and behavioral risk factors for cerebral infarction were examined in 4,349 Japanese men aged 45-74 years with a serum total cholesterol (TC) concentration of 220 mg/dl or greater who participated in the Kyushu Lipid Intervention Study. A total of 81 men developed definite cerebral infarction in a 5-year follow-up period. The Cox proportional hazards model was used with serum TC at baseline and during the follow-up, serum high-density lipoprotein-cholesterol (HDL-C), HT, diabetes mellitus (DM), and other factors as covariates. Serum TC during the follow-up, not at baseline, was positively associated with cerebral infarction, showing a stronger association in the elderly (>or=65 years old) than in the middle-aged (<65 years old). Statin use was related to a moderate decrease in the risk of cerebral infarction when follow-up TC was not considered, but the decrease was almost nullified after adjustment for follow-up TC. A low concentration of serum HDL-C, diabetes mellitus, hypertension, and angina pectoris were each related to an increased risk. No clear association was observed for body mass index, smoking or alcohol use.

CONCLUSIONS

Lowering cholesterol is important in the prevention of cerebral infarction in men with moderate hypercholesterolemia. A low concentration of HDL-C, DM, and HT are independent predictors of cerebral infarction.

Clinical and angiographic predictors of luminal changes beyond 6 months after implantation of thicker strut coronary stents

BACKGROUND

Late luminal changes beyond 6 months after thicker strut stent implantation have not been fully elucidated. The purpose of this study was to clarify the clinical and angiographic predictors of late changes in minimal lumen diameter (MLD) after 6-month follow-up of stenting.

METHODS AND RESULTS

Fifty-one lesions from 44 patients who underwent successfully S670/660 stent (Medtronic Vascular, Santa Rosa, CA, USA) implantations without target lesion revascularization were studied at 6-month follow-up and coronary angiography was repeated after the follow-up. Late luminal loss beyond 6 months after stenting significantly correlated with late loss (r=-0.42, p=0.0025) and MLD (r=0.28, p=0.047) at 6-month follow-up. On multivariate analysis, age (p=0.005), diabetes mellitus (p=0.002), hyperlipidemia (p=0.023), smoking (p=0.015), bifurcation lesion (p=0.018), small stent diameter (p=0.001) and MLD at 6-month follow-up (p<0.001) were identified as independent predictors of late luminal loss.

CONCLUSIONS

This study demonstrated that older age, diabetes mellitus, hyperlipidemia, smoking and small stent diameter (<3.0 mm) were associated with late luminal loss beyond 6 months after stenting, and that a bifurcation lesion and small lumen diameter at 6 months were associated with late luminal recovery.

Three-Year Follow-up Results of Angiographic Intervention Trial Using an HMG-CoA Reductase Inhibitor to Evaluate Retardation of Obstructive Multiple Atheroma (ATHEROMA) Study

BACKGROUND

The cardiovascular event rate in Japanese populations is strikingly lower than that in Caucasian populations and it has been postulated that this difference might be because of variations in atherosclerosis progression in patients with coronary artery disease (CAD). However, the rate of angiographically assessed progression and its response to statins has not been well described in Japanese patients.

METHODS AND RESULTS

The angiographic intervention trial using an HMG-CoA reductase inhibitor to evaluate the retardation of obstructive multiple atheroma (ATHEROMA) study was a multicenter, randomized, controlled clinical trial investigating the effects of pravastatin on coronary atherosclerosis in Japanese patients with CAD using quantitative coronary angiography. In total, 361 patients with mild to moderate elevated serum total cholesterol concentrations (195-265 mg/dl) received diet only (n = 179) or diet plus pravastatin 10-20 mg/dl (n = 182). Over 3 years, low-density lipoprotein-cholesterol in the pravastatin group decreased by 19.5% (p < 0.0001). A per-patient analysis showed that minimum lumen diameter increased by 0.034+/-0.17 mm in the pravastatin group, but decreased by 0.006+/-0.16 mm in the diet only group (p = 0.04). The mean difference between the treatment groups was 0.040 mm (95% confidence interval 0.020, 0.070 mm).

CONCLUSION

The ATHEROMA study indicates that pravastatin 10-20 mg/day for 3 years improves hyperlipidemia, then suppresses progression and induces regression of focal coronary atherosclerosis in Japanese CAD patients with elevated serum cholesterol.

Effect of Smoking on Endothelial Function and Wall Thickness of Brachial Artery

BACKGROUND

Impaired flow mediated dilatation (FMD) and increased wall thickness (WT) of the brachial artery have been associated with atherosclerosis and its risk factors. In this study we sought to determine brachial artery wall thickness in chronic smokers and the instantaneous effect of smoking on brachial artery endothelium dependent vasodilator function in smokers and non-smokers.

METHOD AND RESULTS

Using a high-resolution ultrasound, WT of posterior brachial artery wall, the diameter of brachial artery at rest and during reactive hyperemia (FMD %), as well as after sublingual administration of nitroglycerine (nitroglycerine mediated dilatation (NMD) %) was measured in 20 smokers and 20 non-smokers. Wall thickness (WT) of the posterior brachial artery wall and the wall index (WI) were greater in smokers than non-smokers. The baseline brachial artery diameter was comparable in smokers and non-smokers. Flow mediated dilation (FMD) was found to be less in smokers than non-smokers. The NMD in smokers also did not differ significantly from that in non-smokers. Flow mediated dilation significantly reduced after smoking compared to baseline in both groups. However, NMD remained unchanged after smoking in both groups.

CONCLUSIONS

Increased WT and impaired endothelium-dependent dilatation of brachial artery suggests that cigarette smoking disrupts vessel wall morphology long before atherosclerosis is manifest.