Cholesterol confusion in primary prevention of coronary artery disease

Summary Despite the impressive relation between an increased blood cholesterol and increased mortality from coronary artery disease and despite the persuasive results of cholesterol-lowering trials in secondary prevention, there are increasing reservations about the wisdom of lowering moderately raised blood cholesterol levels in patients who have no symptoms of coronary artery disease. In particular, there are important differences between total mortality and cardiovascular mortality, and between relative and absolute risks. A policy that may be practiced by clinical cardiologists is proposed. In essence, each patient should be assessed for all the chief cardiovascular risk factors in that particular individual. Primary prevention by cholesterol reduction in the absence of symptoms of coronary artery disease requires very careful judgement and should only be undertaken when there is good evidence that the risk of coronary artery disease can be reduced in absolute terms. For primary prevention to be effective requires that the whole gamut of coronary risk factors should be addressed.     

Exercise in the primary prevention of coronary artery disease

Since the 1950s there has been a steady accumulation of data from observational studies and clinical trials identifying a lack of physical activity, either in the industrial or leisure setting, as an independent major risk factor for coronary artery disease, with a similar relative risk as smoking, hypercholesterolemia and hypertension. More recently, poor cardiorespiratory fitness has also been shown to increase the risk of cardiovascular mortality significantly. Regular exercise is now known to have beneficial effects on peripheral and central circulation, skeletal muscle and myocardium, as well as lipid and carbohydrate metabolism. Individuals who become active in later life, for example, by way of a moderate intensity walking program, and who make only modest gains in fitness, nevertheless share in many of these health benefits and reduce their coronary artery disease risk. It is estimated that 60% of Canadians are physically inactive, a higher prevalence than for the other major risk factors. Consequently, efforts to encourage a more active lifestyle can have a significant impact on cardiovascular morbidity and mortality, with a marked reduction in costs to the health care system.     

Screening coronary arteriography in the primary prevention of coronary artery disease

Recent studies indicate an expansion of the population eligible for primary prevention of coronary artery disease with lipid-lowering therapy. This change has led to the unnecessary treatment of many individuals and an overall decreased effectiveness of medication with potentially significant side effects. If instead, the asymptomatic population is screened for the presence of early coronary artery disease (CAD), lipid lowering can be targeted to those who can truly benefit. The prevalence of asymptomatic CAD in men older than 50 years of age approaches 20% and arteriography is currently the best available test to identify these men. The approximate complication rate of arteriography in such a population (1 or 2 per 10,000) approaches that of other screening tests. Although insufficient data exists for formal cost analysis, approximations indicate significant savings for arteriographically targeted treatment of at-risk asymptomatic individuals. The authors show that coronary arteriography is a potentially safe and cost-effective method of screening an asymptomatic adult population for presence of early CAD, allowing for the targeting of lipid lowering to those who can benefit most from this therapy.     

The secondary prevention of coronary artery disease in older persons

Coronary artery disease (CAD) is the leading cause of morbidity and mortality in older persons and has considerable health care costs. Older persons are a unique socioeconomic group that is underrepresented in clinical trials. They have atypical clinical presentations and vary in response to medications. This review discusses the risk factors of CAD and the secondary prevention of CAD, with a specific focus on the older age group. This article briefly reviews the paradox of care and the quality of care in the older population.     

Nonlipid primary and secondary prevention strategies for coronary heart disease

Widespread application of proven primary and secondary preventive strategies for coronary heart disease would result in substantial savings of life and health care dollars. Proven strategies (excluding lipid therapy) include quitting smoking, treating hypertension, physical activity, aspirin therapy, and appropriate use of anticoagulants, beta blockers, and angiotensin-converting enzyme inhibitors in survivors of myocardial infarction. Estrogen replacement therapy is currently under clinical investigation. Avoidance of obesity and tight control of diabetes are prudent interventions as yet unproved by clinical trials. Unfortunately, preventive strategies are frequently underutilized. The greatest challenge for preventive cardiology is to put into practice what we already know to prevent the development and progression of atherosclerosis.     

150例冠心病患者二级预防的效果

目的:调查分析本院冠心病人二级预防的效果。方法:对明确诊断为冠心病,并曾住院治疗的150例患者,进行门诊随访,以问卷的方式,对其冠心病二级预防的情况进行调查。所有患者均进行病史询问,汇总分析了解戒烟、控制血压、血糖,调脂治疗等的效果。结果:150例患者与住院前比较,住院后门诊随访的戒烟率(38%:58%),血压达标率(26.7%:68.7%)、血脂达标率(20.7%:54.0%)、血糖达标率(51.3%:72.7%)、运动达标率(7.3%:22.7%),以及使用阿司匹林、氯吡格雷、他汀类药物、β受体阻滞剂、血管紧张素转换酶抑制剂类有显著增加(P均0.05),说明二级预防的效果及依从性均有显著提高。结论:冠心病二级预防的效果甚好,应推广,普及。     

Monotherapy with hMG-CoA reductase inhibitors and secondary prevention in coronary artery disease

Although thrombolytic drugs, percutaneous transluminal coronary angioplasty, and coronary artery bypass grafting have provided major advances in the treatment of coronary artery disease, the use of lipid-lowering drugs for secondary prevention has significantly reduced cardiovascular events in the population with coronary artery disease. Secondary prevention trials using HMG-CoA reductase inhibitors include the Familial Atherosclerosis Treatment Study (FATS), the Monitored Atherosclerosis Regression Study (MARS), the Canadian Coronary Atherosclerosis Intervention Trial (CCAIT), the Asymptomatic Carotid Artery Progression Study (ACAPS), the Multi Anti-Atheroma Study (MAAS), the Scandinavian Simvastatin Survival Study (4S), the Pravastatin Limitation of Atherosclerosis in Coronary Arteries (PLAC I), the Regression Growth Evaluation Statin Study (REGRESS), the Pravastatin Multinational Study, and the Pravastatin, Lipids, and Atherosclerosis in Carotids (PLAC II). Mean changes from baseline of lipid fractions in these trials included: total cholesterol 18 to 35% reduction low-density lipoprotein (LDL) cholesterol 26 to 46% reduction high-density lipoprotein (HDL) cholesterol 5 to 15% increase and triglyceride 7 to 22% reduction. Angiographic regression or lack of progression was statistically demonstrated in the FATS, MARS, CCAIT, MAAS, PLAC I, and REGRESS trials. Cardiovascular events decreased 25 to 92% in all trials, and there was a significant reduction in both cardiovascular and total mortality in the 4S. The greater reduction in cardiovascular events than in anatomic changes suggests that the HMG-CoA reductase inhibitors stabilized the surface of plaques. Monotherapy with HMG-CoA reductase inhibitors provides the clinical opportunity to modify the natural history of coronary artery disease.