Prevention of progression of coronary atherosclerosis by treatment of hyperlipidaemia: a seven year prospective angiographic study

High density lipoproteins and coronary atherosclerosis. A strong inverse relation with the largest particles is confined to normotriglyceridemic patients

The relations of high density lipoprotein (HDL) subclasses to severity and rate of progression of coronary atherosclerosis were investigated in 60 men who had survived a myocardial infarction before the age of 45 years and who had subsequently undergone two coronary angiographies, with an intervening time interval of 4-7 years between angiographies. Five HDL subclasses with different particle sizes were determined by gradient gel electrophoresis, and the major serum lipoprotein classes were separated by preparative ultracentrifugation in connection with the second angiography. Highly significant inverse correlations were found between the plasma levels of the largest HDL particles, the HDL2b subclass, and both disease severity as observed on the second coronary angiogram (r = -0.53, p less than 0.001) and progression of coronary lesions between angiographies (r = -0.38, p less than 0.01). Grouping the patients according to the presence or absence of very low density lipoprotein (VLDL) triglyceride elevation revealed striking differences in the relations of HDL subspecies to coronary atherosclerosis between normotriglyceridemic and hypertriglyceridemic subjects. There were strong inverse correlations between the plasma HDL2b concentration and both severity of lesions (r = -0.72, p less than 0.001) and rate of lesion progression (r = -0.58, p less than 0.01) in the normotriglyceridemic patients, whereas this relation was absent in subjects with hypertriglyceridemia.(ABSTRACT TRUNCATED AT 250 WORDS)

Effects of therapy with diet and simvastatin on atherosclerosis in hypercholesterolemic patients

We evaluated the effect of cholesterol reduction on atherosclerotic coronary artery lesions using diet and simvastatin, a potent HMG CoA reductase inhibitor. Fifteen subjects aged 28-69 years (mean 44), each of whom demonstrated significant (greater than 50%) narrowing of a coronary artery and a baseline cholesterol level greater than 278 mg/dl, were studied. Coronary arteriography was performed prior to and after 20 +/- 2.5 months of therapy. A 42% reduction in total serum cholesterol, a 52% reduction in LDL cholesterol, and an 87% increase in the HDL/LDL cholesterol ratio (p less than 0.01) were achieved. Pretreatment and posttreatment angiograms were reviewed by three experienced angiographers with temporal order masked. Improvement in the overall status of coronary atherosclerotic lesions was demonstrated in two patients (13%), while deterioration occurred in one patient (7%). No overall change was found in the remaining 12 patients (80%). We conclude that a cholesterol-lowering regimen using a nonatherogenic diet and simvastatin therapy may at least stabilize coronary atherosclerosis.

Guidelines for the detection of high-risk lipoprotein profiles and the treatment of dyslipoproteinemias. Canadian Lipoprotein Conference Ad Hoc Committee on Guidelines for Dyslipoproteinemias

Elevated plasma levels of cholesterol and triglycerides, low levels of high-density lipoproteins, hypertension, diabetes mellitus, smoking and abdominal obesity are risk factors for coronary heart disease (CHD) and stroke. Because of the preventable threat to life, well-being and productivity from perturbations of plasma lipoproteins (which affect about 60% of adults), we recommend a population-based strategy with public education on diet, exercise and the hazards of smoking and legislation for better food labelling. This should be combined with the medical guidelines we describe to detect and treat those at highest risk for CHD (including about 15% of adults), who merit priority for the medical, dietetic and laboratory services required. Among people aged 40 years or more this includes those with plasma total cholesterol levels greater than 7 mmol/L, fasting triglyceride levels greater than 3 mmol/L or cholesterol level greater than 6 mmol/L when associated with CHD or other risk factors for CHD. For younger people the criteria for highest risk include cholesterol levels greater than 6.5 mmol/L for those aged 30 to 39 years, greater than 6 mmol/L for those aged 20 to 29 and greater than 5 mmol/L for those under age 20.

Ten-year mortality from cardiovascular disease in relation to cholesterol level among men with and without preexisting cardiovascular disease

To determine the associations of total, low-density lipoprotein (LDL), and high-density lipoprotein (HDL) cholesterol with mortality from coronary heart disease and cardiovascular disease, we studied 2541 white men who were 40 to 69 years old at base line and followed them for an average of 10.1 years. Seventeen percent had some manifestation of cardiovascular disease at base line, whereas the others did not. Among the men who had cardiovascular disease at base line, we found, after multivariate adjustment, that those with "high" blood cholesterol levels (above 6.19 mmol per liter) had a risk of death from cardiovascular disease, including coronary heart disease, that was 3.45 times higher (95 percent confidence interval, 1.63 to 7.33) than that for men with "desirable" blood cholesterol levels (below 5.16 mmol per liter). The corresponding hazard ratios were 5.92 (95 percent confidence interval, 2.59 to 13.51) for LDL cholesterol levels above 4.13 mmol per liter as compared with those below 3.35 mmol per liter, and 6.02 (95 percent confidence interval, 2.73 to 13.28) for HDL cholesterol levels below 0.90 mmol per liter as compared with those above 1.16 mmol per liter. All three lipid levels were also significant predictors of death from coronary heart disease alone (P less than 0.005). Total cholesterol and LDL cholesterol levels were also significant predictors of death from cardiovascular and coronary heart disease in men without preexisting cardiovascular disease, although at a lower level of absolute risk of death. Thus, the 10-year risk of death from cardiovascular disease for a man with preexisting cardiovascular disease increased from 3.8 percent to almost 19.6 percent with increasing levels of total cholesterol from "desirable" to "high," whereas the corresponding risk for a man who was free of cardiovascular disease at base line increased from 1.7 percent to 4.9 percent. Our findings suggest that total, LDL, and HDL cholesterol levels predict subsequent mortality in men 40 to 69 years of age, especially those with preexisting cardiovascular disease.

International nifedipine trial on anti-atherosclerotic therapy (INTACT)--methodologic implications and results of a coronary angiographic follow-up study using computer-assisted film analysis

Animal experiments demonstrated a significant suppressive effect of various calcium channel blockers on the formation of atherosclerotic lesions. Therefore, a prospective, placebo-controlled, randomized, double blind multicenter study was performed to investigate the inhibitory influence of the calcium channel blocker nifedipine (80 mg/day) on the progression of coronary artery disease in man. Study endpoints were changes of coronary morphology documented by coronary angiography with particular respect to the formation of new coronary stenoses. In 348 out of 425 patients included in the study, coronary angiograms were repeated after three years. The angiograms were standardized by induction of a maximal coronary vasodilation with high doses of nitrates and by using absolutely identical angiographic projections. Quantitative analysis of coronary cineangiograms was performed with the computer-assisted contour detection system CAAS. Parameters were mean and minimal diameter of all segments and minimal stenosis diameter, percent diameter stenosis, length and plaque area of all stenoses. Continuous intake of study medication was registered in 282 patients, 134 on nifedipine and 148 patients on placebo. In these patients, a total of 3808 coronary segments with 893 stenoses (greater than or equal to 20% diameter reduction in at least one angiographic projection) were compared on the baseline and follow-up cineangiograms. The changes in all angiographic parameters analyzed averaged over all patients by considering all angiographic projections analyzed, indicated significant progression of the disease (p less than 0.006). The average changes in all parameters were even about three times more profound, when in the individual patients only the respective projections indicating the maximal changes were considered for the calculation (p less than 0.001). However, with neither of these two analysis modes, the differences in progression between the treatment groups were statistically significant. In the follow-up angiograms, a total of 196 new coronary lesions (185 stenoses, 11 occlusions) were found at previously normal arterial sites. In patients on nifedipine, an average of only 0.58 new lesions per patient were detected versus 0.80 lesions per patient on placebo (-27%; p = 0.031). INTACT is the first prospective angiographic trial on the progression of coronary artery disease using computer-assisted quantitative coronary angiography in such a high number of patients. All parameters analyzed indicated significant progression of coronary artery sclerosis. Nifedipine had no influence on the progression of preexisting coronary stenoses, but inhibited significantly the formation of new angiographically recognizable lesions. Further prospective coronary angiographic trials with calcium channel blockers using a comparably exact method are needed to confirm the results of this study.

A three-year evaluation of metabolic changes in Singaporean Norplant-2 rod acceptors

In this longitudinal study involving 100 Singaporean women, the effects of Norplant-2 rods on metabolic function were evaluated. With respect to liver function, the results indicate possible hepatocellular dysfunction as evidenced by a significant rise in serum bilirubin and a significant fall in total proteins and globulin during the three years of use. As regards lipid metabolism total triglycerides, cholesterol and LDL cholesterol were significantly decreased as compared to their preinsertion values at the end of three years. The HDL-cholesterol was also significantly decreased during the second and third year of use. Despite this, the HDL-cholesterol/total-cholesterol-HDL-cholesterol remained above 0.200. Thus, though speculative, it still appears to indicate that use of Norplant-2 rods is not directly contributory to cardiovascular risk. The use of Norplant-2 was not associated with any significant effect on carbohydrate metabolism after three years of use.

A new method of scoring coronary angiograms to reflect extent of coronary atherosclerosis and improve correlation with major risk factors

We developed a new angiographic score of the extent of coronary disease (extent score), which we compared with conventional stenosis and vessel scores that emphasize the severity of stenosis. Scores were determined in 132 patients (29 women, 103 men with a mean age of 55 +/- 10 years) who underwent elective coronary angiography. Risk factors were more closely related to the extent score than to either the stenosis or vessel scores (Total R2 = 0.35 versus 0.28 (p less than 0.001) and 0.25 (p less than 0.001), respectively). The extent score was more closely related to age (r = 0.30, p less than 0.05), than was either stenosis (r = 0.21 ns) or vessel score (r = 0.26, p less than 0.05). Apolipoprotein B was the strongest predictor of both extent and stenosis scores but was more closely related to the extent score (r = 0.36, p less than 0.05), even after correction for age and gender. This new angiographic score that assesses the extent of coronary disease is simple to perform and correlates better with age and lipoprotein risk factors than conventional scores do.

The effect of serum lipid regulation on the development of femoral atherosclerosis in hyperlipidaemia: a non-randomized controlled study

The development of femoral atheroma after 1 year of treatment with diet and nicotinic acid plus fenofibrate was studied in 45 asymptomatic, hyperlipidaemic, middle-aged male subjects in a non-randomized controlled study. The median serum very low density lipoprotein (VLDL) cholesterol concentration and the low density lipoprotein (LDL) cholesterol concentration were lowered by 67% and 36%, respectively, in the treatment group. The median serum high density lipoprotein (HDL) cholesterol concentration was increased by 23%. Femoral atheroma was estimated by overall atherosclerosis score (OAS). Changes in femoral atherosclerosis were estimated by intrapair comparison of angiograms. Progression was found in 24% and 40% in the treatment and control groups, respectively. Regression occurred in 29% and 0%, respectively. The OAS decrease correlated with reductions in VLDL cholesterol and systolic blood pressure.

Reduction in Q wave myocardial infarctions with gemfibrozil in the Helsinki Heart Study

The Helsinki Heart Study demonstrated a 34% (p less than 0.02) reduction in the incidence of cardiac end points (myocardial infarction and cardiac death) with the use of gemfibrozil compared with the use of a placebo in dyslipidemic middle-aged men. The major effect was confined to nonfatal myocardial infarctions. In this study we analyzed the effect of gemfibrozil therapy on the incidences of Q wave and non-Q wave infarctions, since the long-term prognoses of these two types of myocardial infarction may be different. The analyses indicated a 45% reduction (P less than 0.02, log-rank test) in the cumulative incidence of Q wave infarctions in the gemfibrozil group without a statistically significant effect on either the rate of non-Q wave infarctions or of coronary deaths. The reduction in the incidence of Q wave infarctions became evident during the second half of the 5-year study period.

A three-year evaluation of metabolic changes in Singaporean Norplant acceptors

In a longitudinal study involving 100 Singaporean women, the effect of NorplantR on metabolic function was evaluated. With respect to liver function, the results indicate possible hepatocellular dysfunction as evidenced by a significant rise in serum bilirubin and a significant fall in total proteins and globulin during the period under review. As regards lipid metabolism, total triglycerides and total cholesterol still remained significantly decreased at the end of the three years. The LDL, which was significantly decreased in the first year, increased during the subsequent two years to its preinsertion value at the end of three years. The HDL-cholesterol levels continued to decrease in the second and third year after a significant increase in the first year. Despite this, the HDL cholesterol/total cholesterol-HDL cholesterol remained above 0.200. As we have not incorporated a simultaneous non-pill treated control group, the observed changes in lipoprotein lipids could be attributed to extraneous factors such as diet, exercise, or other environmental changes. Nevertheless, the findings at the end of three years, though speculative, still appear to indicate Norplant use to be not directly contributory to cardiovascular risk. The use of Norplant was not associated with any significant effects on carbohydrate metabolism after three years of use.

Managing elevated blood lipid concentrations. Who, when and how?

Patients with elevated serum cholesterol concentrations, particularly men, should be treated to lessen their chance of subsequent morbidity from coronary heart disease. Reduction of elevated triglyceride levels is more contentious, but is justified in severely affected individuals. The levels requiring treatment can only be judged by consideration of the overall clinical setting, including patient age and sex, the presence of other risk factors and the particular lipoprotein abnormality. In general, relative youth, male sex, a low level of high density lipoprotein (HDL) cholesterol and a strong family history of coronary heart disease will favour vigorous therapy. The possibility that hyperlipoproteinaemia is secondary to some other metabolic disorder should be considered, particularly in regard to elevated triglyceride levels.

Prevalence and prognostic significance of exercise-induced silent myocardial ischemia detected by thallium scintigraphy and electrocardiography in asymptomatic volunteers

Although a silent ischemic electrocardiographic response to treadmill exercise in clinically healthy populations is associated with an increased likelihood of future coronary events (i.e., angina pectoris, myocardial infarction, or cardiac death), such a response has a low predictive value for future events because of the low prevalence of disease in asymptomatic populations. To examine whether detection of reduced regional perfusion by thallium scintigraphy improved the predictive value of exercise-induced ST segment depression, we performed maximal treadmill exercise electrocardiography (ECG) and thallium scintigraphy (201Tl) in 407 asymptomatic volunteers 40-96 years of age (mean = 60) from the Baltimore Longitudinal Study on Aging. The prevalence of exercise-induced silent ischemia, defined by concordant ST segment depression and a thallium perfusion defect, increased more than sevenfold from 2% in the fifth and sixth decades to 15% in the ninth decade. Over a mean follow-up period of 4.6 years, cardiac events developed in 9.8% of subjects and consisted of 20 cases of new angina pectoris, 13 myocardial infarctions, and seven deaths. Events occurred in 7% of individuals with both negative 201Tl and ECG, 8% of those with either test positive, and 48% of those in whom both tests were positive (p less than 0.001). By proportional hazards analysis, age, hypertension, exercise duration, and a concordant positive ECG and 201Tl result were independent predictors of coronary events. Furthermore, those with positive ECG and 201Tl had a 3.6-fold relative risk for subsequent coronary events, independent of conventional risk factors.(ABSTRACT TRUNCATED AT 250 WORDS)

Lipid metabolism in bile acid malabsorption

Malabsorption of bile acid increases cholesterol synthesis and activates hepatic LDL receptors which leads to enhanced elimination of cholesterol from the body. Interruption of enterohepatic circulation of bile acids may lead to a smaller bile acid pool, which, in turn, impairs cholesterol and fat absorption by reduced micellar solubilization. Together with reduced cholesterol absorption, the increased cholesterol loss as bile acids also reduces plasma cholesterol concentrations and the biliary cholesterol excretion, too. Diminished biliary cholesterol in bile acid malabsorption may contribute to the increased incidence of gallstones associated with ileal dysfunction. Malabsorption of bile acid leads to a fall in LDL-cholesterol concentration, and an increase of HDL-cholesterol concentration has been reported. VLDL-triglyceride concentrations are almost invariably raised. Enhanced cholesterol and bile acid synthesis in ileal dysfunction is reflected by raised concentrations of plasma cholesterol precursors, especially lathosterols, which can be used as an indicator of increased bile acid loss to faeces. Cholesterol absorption, in turn, correlates positively with plasma plant sterol concentrations levels and the ratio of lathosterols to campesterols can be used as a screening measurement for ileal dysfunction. Plasma fatty acid composition is also altered as a response to fat malabsorption associated with ileal dysfunction. The proportion of essential fatty acids is inversely correlated with faecal fat excretion and endogenous fatty acid synthesis is activated.

Preventive cardiology: a progress report

The progress to the current era of preventive cardiology covers a period of more than 40 years, beginning with epidemiological studies on coronary heart disease and other forms of atherosclerotic disease and related factors and progressing through prevention trials and community demonstration projects to the actual implementation of preventive measures by combined population and high-risk strategies. The scientists of the United States have played a leading role in the data collection which forms the scientific basis for preventive cardiology and the fruitful collaboration in the United States between the scientists and governmental, as well as nongovernmental, organizations in the implementation of preventive cardiology has served as a good example for other countries. The Section on Epidemiology and Prevention of the International Society and Federation of Cardiology and the Cardiovascular Diseases Unit of the World Health Organization, working in close liaison, have had key roles in the worldwide promotion of preventive cardiology. The rapid progress in preventive cardiology during the past 4 years, since the 1st International Conference of Preventive Cardiology, has been dominated by a "snowballing" movement toward more intensive application of cholesterol-lowering measures at both the population and the individual level. Promising progress has also been made in the field of nonpharmacological control of elevated blood pressure.

Population strategies of cardiovascular disease prevention: scientific base, rationale and public health implications

Congruence of evidence from all medical research methodologies has established the major causal influences in cardiovascular disease. Causation thus established, epidemiological observations are the best available evidence on which to base estimates of the potential of preventive strategies. From population comparisons we learn that some countries have little cardiovascular disease; therefore, prevention is a reality. From mortality surveillance we learn that the disease processes are highly dynamic. Parallels between cardiovascular disease and major non-cardiovascular disease mortality trends suggest that they have common causes and that common preventive strategies may be effective for both. From migrant studies we learn the predominant contribution to population risk of environment and culture. From population surveys we learn that risk characteristics for cardiovascular disease are mass phenomena, therefore they require mass preventive approaches. Follow-up studies in cohorts provide evidence of the risk attributable to elevated risk characteristics and the potential for preventive strategies in high risk societies with high disease rates. Clinical trials indicate the effectiveness of interventions in high risk individuals, the relative safety of such efforts and that cardiovascular disease prevention effects emerge in a very few years. Public health trials demonstrate that communities can mount and maintain effective preventive programs and what programs work best. Studies in youth indicate that risk of adult disease starts early and that an optimal prevention program would seek to prevent elevated risk in the first place.

The dynamics of progression of coronary atherosclerosis studied in 168 medically treated patients who underwent coronary arteriography three times

To study the dynamics of progression of coronary atherosclerosis we analyzed findings in 168 patients who underwent coronary arteriography three times without undergoing coronary surgery or percutaneous transluminal coronary angioplasty. Of 66 patients who had progression in interval 1 (from first to second coronary arteriogram), 32 also had progression in interval 2 (from second to third coronary arteriogram); of 102 patients who had no progression in interval 1, 37 had progression in interval 2. In only 9 of the 32 patients who had progression during both intervals was the same lesion involved, and in six of these patients other lesions were also involved. Progression correlated with the duration of the interval between catheterizations, an increase in symptoms, and the occurrence of myocardial infarction. Analysis of variance showed no significant differences in mean values for age, blood pressure, total serum cholesterol, and serum triglycerides in the four main progression groups. Progression of coronary atherosclerosis is a highly unpredictable process. It follows a nonlinear course, and information derived from sequential coronary arteriograms is of little value in predicting future progression.

Therapeutic control of hyperlipidemia in the prevention of coronary atherosclerosis: a review of results from recent clinical trials

The link between elevated plasma cholesterol levels and coronary atherosclerosis is now well established. During the past decade, results from therapeutic trials indicate that control of hypercholesterolemia does result in lower cardiovascular risk. Many of these results were obtained in hypercholesterolemic, middle-aged men. Comparable data in women are not available but it is inferred that they would also benefit from cholesterol reduction. Results from the Coronary Drug Project, extended over 15 years, indicate that lipid-lowering therapy with niacin for 5 years was associated with a decrease in total mortality as well as mortality from coronary heart disease. In the studies performed for shorter periods (5 to 7 years), therapy lowered only cardiovascular morbidity and mortality but had no beneficial effect on total mortality. A reduction in cardiovascular risk begins to appear 24 to 28 months after the initiation of therapy and continues to accrue thereafter. The relatively uniform results from recent large-scale clinical trials (Lipid Research Clinics Coronary Primary Prevention Trial, Coronary Drug Project, Helsinki Heart Study) indicate that cholesterol reduction, per se, probably explains the lower cardiovascular morbidity and mortality observed in these trials. As a result of these trials, recent redefinitions of hypercholesterolemia and more aggressive treatment programs have been recommended. These guidelines stress assessment of all cardiovascular risk factors and recommend individualized care of the patient. To control hypercholesterolemia, conservative measures with diet are recommended before therapy with medication is considered. Recent clinical trial experience indicates that the clinician can have significant impact on atherosclerosis by identifying and treating patients with plasma cholesterol levels in the high-risk range.

Treatment of lipid disorders in diabetes mellitus

One reason for premature atherosclerosis in patients with diabetes mellitus is abnormal lipid metabolism. This article discusses the plasma lipid disorders associated with diabetes mellitus, and how to apply the new guidelines from the National Cholesterol Education Program for treatment of hypercholesterolemia in patients with diabetes mellitus.

Clinical and laboratory responses to niceritrol in the treatment of hypercholesterolaemia

Twenty-five hypercholesterolaemic patients from three centres in the UK were investigated in an open study of the efficacy and side effects of niceritrol. Five patients dropped out of the study at an early stage and had insufficient data for analysis. There were 13 males and 7 females (mean age 49.2 years, range 18-69). Fourteen patients had heterozygous familial hypercholesterolaemia, and six polygenic hypercholesterolaemia. Niceritrol was started at a dose of 750 mg/day and this was increased at weekly intervals over 4 weeks to the maximum tolerated dosage up to 3 g/day. This was then maintained for a further 8 weeks. There were statistically significant decreases in total plasma cholesterol, total triglyceride, LDL cholesterol and VLDL triglyceride; HDL cholesterol remained unchanged after 12 weeks of treatment (Wilcoxon matched pairs, signed ranks test). The 14 patients with familial hypercholesterolaemia showed a 13.9% fall in total cholesterol and a 19.8% fall in LDL cholesterol. All patients reported flushing and some had gastrointestinal symptoms but 19 would have been prepared to continue with the therapy at doses up to 3 g/day. Thus niceritrol has been found to be beneficial in the treatment of both familial and polygenic hypercholesterolaemia.

Management of lipids in primary and secondary prevention of cardiovascular diseases

Although the frequency of cardiovascular disease is declining, it remains a major present and future threat to health in the United States. The deleterious effects of abnormal blood lipid concentrations have long been recognized, but the benefit of corrective intervention in this process has only recently been demonstrated. We review the major lipid abnormalities and the available clinical therapeutic interventions. In addition, we discuss data that address the premise that reducing low-density lipoprotein cholesterol or raising high-density lipoprotein cholesterol should decrease the progression of coronary atherosclerosis, and we summarize drug trials in which clofibrate, niacin, cholestyramine, and gemfibrozil decreased coronary heart disease events. Studies that used cholestyramine and the combination of colestipol and niacin resulted in decreased progression of coronary artery disease. On the basis of early experience with lovastatin, inhibitors of hydroxymethylglutaryl-coenzyme A reductase are likely to be effective in the treatment of hypercholesterolemia. The available information on the association of low cholesterol levels and cancer suggests that low total cholesterol is a consequence rather than a cause of carcinoma. Current data strongly support the concept of vigorous intervention directed at management of lipids, both with non-pharmacologic treatment and with drug therapy, for the primary and secondary prevention of coronary atherosclerosis.

Effects of CS-514 on plasma lipids and lipoprotein composition in hypercholesterolemic subjects

The effect of CS-514 (eptastatin, Sankyo Co., Tokyo), a competitive inhibitor of 3-hydroxy-3-methylglutaryl coenzyme A reductase, was investigated in 47 patients with hypercholesterolemia (WHO type IIa: 27, IIb: 20). Ten or 20 mg of CS-514 was administered daily for 3 months. In both types of patient, total cholesterol and phospholipid levels were significantly reduced by CS-514. The triglyceride, cholesterol and phospholipid content of low density lipoprotein (LDL) and the plasma levels of apolipoprotein B were also decreased in both groups. In contrast, total triglyceride, very low density lipoprotein (VLDL)-triglyceride and apolipoprotein C-II were decreased only in type IIb subjects. Also the levels of high density lipoprotein (HDL)-cholesterol and apolipoproteins A-I and A-II were increased by CS-514 in IIb but not in IIa patients. In both groups, no change occurred in either the cholesterol/triglyceride or phospholipid ratio in any lipoprotein fraction, nor in the ratio of HDL-cholesterol to apolipoprotein A-I or A-II, respectively. Therefore, CS-514 suppresses plasma levels of cholesterol in hypercholesterolemic patients without modifying lipoprotein composition. Moreover, this drug has different effects on the levels of plasma triglyceride and HDL-cholesterol of type IIa and IIb patients.

Low-fat diet and regular, supervised physical exercise in patients with symptomatic coronary artery disease: reduction of stress-induced myocardial ischemia

The effects of physical exercise and normalization of serum lipoproteins on stress-induced myocardial ischemia were studied in 18 patients with coronary artery disease, stable angina pectoris, and mild hypercholesterolemia (total serum cholesterol 242 +/- 32 mg/dl). These patients underwent a combined regimen of low-fat/low-cholesterol diet and regular, supervised physical exercise at high intensity for 12 months. At 1 year serum lipoproteins has been lowered to ideal levels (serum cholesterol 202 +/- 31 mg/dl, low-density lipoproteins 130 +/- 30 mg/dl, very low-density lipoproteins 22 +/- 15 mg/dl, serum triglycerides 105 [69 to 304] mg/dl) and physical work capacity was improved by 21% (p less than .01). No significant effect was noted on high-density lipoproteins, probably as a result of the low-fat/high-carbohydrate diet. Stress-induced myocardial ischemia, as assessed by thallium-201 scintigraphy, was decreased by 54% (p less than .05) despite higher myocardial oxygen consumption. Eighteen patients matched for age and severity of coronary artery disease served as a control group and "usual medical care" was rendered by their private physicians. No significant changes with respect to serum lipoproteins, physical work capacity, maximal rate-pressure product, or stress-induced myocardial ischemia were observed in this group. These data indicate that regular physical exercise at high intensity, lowered body weight, and normalization of serum lipoproteins may alleviate compromised myocardial perfusion during stress.

Changes in lipid and lipoprotein levels and Achilles tendon diameters and indices in familial hypercholesterolaemic patients with tendinous xanthomatosis treated by diet and bezafibrate for 2 years

Thirteen young adult patients suffering from heterozygotic familial hypercholesterolaemia with tendinous xanthomatosis, previously treated with a suitable special diet, were studied to assess the effect of bezafibrate, given for 2 years at a dose of 800 mg/day, on plasma lipid and lipoprotein levels and on changes in size of the Achilles tendon xanthomas. Measurements were made before and at intervals during treatment, the tendinous xanthomas being measured by an echographic procedure to give data on antero-posterior and lateral diameters, thus enabling an Achilles tendon index to be defined. The results confirm the hypolipidaemic activity of bezafibrate, changes in the levels of total cholesterol, triglycerides, lipids and lipoproteins (LDL, VLDL and HDL) being similar in direction and magnitude to those reported previously. A significant regression in the size of the Achilles tendon xanthomas was observed in 11 of the 13 patients, and the regression in the Achilles tendon index correlated significantly with a favourable change in the ratio HDL/LDL + VLDL. It is suggested that, as a result of this objective observation, a favourable effect of bezafibrate treatment would possibly be seen on the anatomical atheromatous lesions which are usual in this type of hyperlipidaemia.

The Cholesterol Lowering Atherosclerosis Study (CLAS): design, methods, and baseline results

The Cholesterol Lowering Atherosclerosis Study (CLAS) is a prospective, placebo-controlled, angiographic trial designed to test the hypothesis that aggressive lowering of LDL cholesterol with concomitant increase in HDL cholesterol will reverse or retard the atherosclerotic process. Specifically, CLAS was designed to determine whether combined therapy with colestipol plus niacin will produce clinically significant change in coronary, carotid, and femoral artery atherosclerosis and coronary bypass graft lesions. To this purpose, 188 subjects were randomized to diet plus drug or diet plus placebo. We report on methodological aspects of planning and evaluating this study, including the choice of the study population, procedures for recruitment, the experimental design including sample size considerations, methods for evaluating outcome, and methods for evaluating compliance to treatment. Comparison of baseline data indicated no significant differences between groups at the time of randomization. Subjects were predominantly male, Caucasian, 54 years of age, 20% above ideal weight, with normal blood pressure. The average age at bypass was 50 years. The average lipids were cholesterol (243 mg/dL), HDL (45 mg/dL), and LDL (168 mg/dL). Finally, the distribution of baseline coronary stenosis was equivalent between the two groups (average number of lesions per subject = 10.6).

The effect of exercise on lipid metabolism in men and women

Lipoprotein abnormalities constitute a major risk for development of cardiovascular disease. These substances, which are comprised of various lipids and proteins (apoproteins), are influenced by specific enzymes which effect their concentrations. It has been demonstrated that elevated total cholesterol and LDL cholesterol are directly associated with the development of coronary artery disease, whereas HDL cholesterol has an inverse relationship with coronary heart disease (CHD). Although more controversial, triglycerides may also be directly associated with coronary atherosclerosis. Favourable changes in lipid levels have been shown to reduce coronary mortality. Exercise may constitute a non-pharmacological approach to lipoprotein therapy. Many exogenous factors also influence lipoprotein concentrations. Changes in diet, body composition, age, as well as medication and alcohol usage may directly alter lipid levels. In addition, they can be artificially affected by the analytical method. The immediate effects of one to several bouts of physical activity appear to influence lipoprotein level. A reduction in triglycerides has been shown after physical exertion, especially among trained individuals and those with hypertriglyceridaemia. These acute changes may reflect the utilisation of both muscle and plasma triglycerides as fuels during exertion. After more prolonged training, changes in lipoproteins may also occur. However, since exercise is accompanied by many co-variables which also favourably alter these levels (e.g. lower percentage of body fat, dietary alterations), it is difficult to determine the direct effect of regular physical activity. Initial studies of exercise training's effects on total cholesterol did not differentiate changes in HDL and LDL cholesterol. Subsequent research has observed these specific cholesterol fractions. Consistent reduction in LDL cholesterol levels have not been convincingly demonstrated. Although HDL cholesterol has been shown to increase in certain studies, the response has been variable in other investigations. These latter responses may have been due to the fact that HDL cholesterol changes may be dependent on levels prior to conditioning. Assessment of HDL cholesterol subfractions (HDL2 and HDL3), which could additionally impact on cardiovascular risk reduction, have shown favourable increases in HDL2, but as yet these HDL moieties have not been adequately investigated. Reductions in triglyceride levels after training among those with elevated values and beneficial apoprotein changes post-training have been reported, although few studies exist.(ABSTRACT TRUNCATED AT 400 WORDS)

High-density lipoprotein: a major risk factor for coronary atherosclerosis

The high-density lipoproteins (HDL) are a polydisperse family of lipid--protein complexes whose principal functions in lipid transport are: (1) to act as a reservoir of C apoproteins required for triglyceride transport; (2) to act as a 'scavenger' of surplus cholesterol and phospholipid liberated from lipolysed triglyceride-rich lipoproteins; and (3) to transport surplus cholesterol from peripheral tissues to the liver for excretion and catabolism (reverse cholesterol transport), both directly and indirectly via other lipoproteins and the lipid transfer protein. The concentration of HDL cholesterol (mostly cholesteryl ester) has been found to be a strong risk factor for coronary atherosclerosis, and its clinical complications in most industrialized communities have been studied. The association with disease risk is independent of other lipoproteins and risk factors, has been found in both sexes, and persists following reduction of plasma lipids by diet and certain drugs. It is not yet clear whether or not certain HDL subclasses and/or apoproteins are better predictors of risk than HDL cholesterol. Indirect evidence from clinical studies and data from animal experiments suggests that certain pharmacologically induced increases in HDL cholesterol concentration are associated with a reduction of atherogenesis. However, the mechanism of the link between HDL and atherogenesis is not yet clear: although the original suggestion that it reflects the function of HDL in reverse cholesterol transport remains plausible, alternative mechanisms are possible. These include effects of HDL on platelet function and prostacyclin synthesis. Alternatively, the association might be indirect, reflecting an atherogenic effect of triglyceride-rich lipoproteins and/or their remnants, the plasma concentrations of which are correlated with HDL cholesterol.

Bezafibrate. A review of its pharmacodynamic and pharmacokinetic properties, and therapeutic use in hyperlipidaemia

Bezafibrate is a lipid-lowering drug, chemically related to clofibrate. At its recommended dosage of 200 mg 3 times daily, or alternatively 400 mg once daily as a sustained-release preparation, it produces substantial reductions in plasma triglyceride and cholesterol concentrations in patients with hypertriglyceridaemia and hypercholesterolaemia, respectively. Preliminary investigations indicate that a single daily dose of 400 mg in a sustained-release preparation is as effective as 200 mg 3 times daily. In patients with any type of hyperlipoproteinaemia bezafibrate also increases the plasma HDL-cholesterol concentration. These effects are equivalent in patients with primary hyperlipoproteinaemia or hyperlipoproteinaemia secondary to diabetes or renal disease, although dosage adjustment is important in the latter group. During long term therapy (2 to 4 years) the influence of bezafibrate on the lipid profile is sustained. The lipid-lowering effects of bezafibrate are at least equivalent to those of clofibrate, fenofibrate, colestipol, probucol or sustained release etofibrate. In addition, the increase in HDL-cholesterol tends to be at least as great as with all alternative treatments studied. Bezafibrate is rapidly eliminated, and thus does not accumulate during prolonged administration in patients with normal renal function. Experimental studies have shown bezafibrate to have a complex range of effects on lipoproteins and on the enzymes and receptors involved in lipid metabolism. However, its exact mechanism of lipid-lowering action is unclear. Bezafibrate enhances anticoagulation in hyperlipoproteinaemic patients requiring anticoagulant therapy, and preliminary investigations indicate that it reduces the plasma fibrinogen concentration, especially in patients with hyperfibrinogenaemia. These properties of bezafibrate could contribute to an antiatherogenic effect of the drug, but further investigation is required to establish the drug's potential as chronic therapy in patients with hyperfibrinogenaemic atherosclerosis. Adverse reactions to bezafibrate have largely been restricted to gastrointestinal disturbances, with some cutaneous reactions and central nervous system effects. The incidence of side effects has been no greater than with comparative lipid-lowering drugs. In patients with renal disease, a few cases of marked elevation of serum creatine phosphokinase and myoglobin, and associated muscle cramps, have been reported (diagnosed as rhabdomyolysis). Hepatic enzyme induction by bezafibrate in rats results in hepatomegaly, but there has been no case of significant hepatotoxicity in man.(ABSTRACT TRUNCATED AT 400 WORDS)

Plasma exchange and low density lipoprotein apheresis in Watanabe heritable hyperlipidemic rabbits

Comparison of the effects of plasma exchange using lipoprotein-deficient plasma with those of LDL apheresis using a dextran sulphate column was undertaken in two groups of Watanabe heritable hyperlipidemic rabbits pre-labelled with 3H-cholesterol. Total and HDL cholesterol were reduced more by plasma exchange but HDL cholesterol rebounded higher after LDL apheresis; rises in HDL cholesterol correlated with preceding decreases in both HDL and total cholesterol. An increase in the specific activity of HDL cholesterol occurred on the day after each procedure, being more marked after plasma exchange, and was accompanied by a decrease in the cholesterol/phospholipid ratio of HDL. These results suggest that an influx of extravascular HDL into plasma occurred after both procedures, resulting in mobilization of tissue cholesterol.

Effects of fenofibrate on lipids, lipoproteins, and apolipoproteins in 33 subjects with primary hypercholesterolemia

The effects of fenofibrate on lipids, lipoproteins, and apolipoproteins in 33 subjects with primary hypercholesterolemia were assessed in a 6-month parallel group study, placebo (n = 15) versus fenofibrate 300 mg/day (n = 18), followed by an open label 6-month treatment period. After stabilization on an isocaloric low fat (less than 35% total calories) diet with less than 250 mg cholesterol/day and a P/S ratio of 1, and maintenance of LDL-cholesterol (LDL-C) levels greater than or equal to 175 mg/dl, subjects received placebo for 6 weeks and were then randomized into placebo or fenofibrate groups for 6 months, followed by open label treatment for 6 months. During the 6-month double-blind period, compared to the placebo group, the treatment group had significant reductions in total cholesterol, LDL-C, total apo B, and triglyceride, and increments in HDL-cholesterol, apolipoprotein A-I and apolipoprotein A-II (P less than 0.01 for all comparisons). Compared to placebo baseline, therapy with fenofibrate resulted in a reduction of LDL-C, apo B, and the LDL-C/HDL-C ratio of 15%, 13%, and 18% respectively; HDL-C, apo A-I, and apo A-II increased respectively 12%, 13% and 30% (P less than 0.01 for all comparisons). Mean adherence during the double blind phase of the trial was 95% in the drug group and 96% in the placebo group. An additional 6 months of open label fenofibrate therapy maintained the reduced total and LDL-C as well as the elevated HDL-C, apo A-I and apo A-II in the drug-drug group.(ABSTRACT TRUNCATED AT 250 WORDS)

Medical management of hyperlipidemia and the role of probucol

Recent experimental and epidemiologic evidence has dispelled all doubts about the need to treat patients with hyperlipidemia. Therapy should focus on 3 areas: control of concomitant risk factors for atherosclerosis, reduction of lipid levels through diet and, if response to diet proves inadequate, administration of lipid-lowering agents. There are 4 categories of first-line drugs: resins, fibrates, nicotinic acid and probucol. Probucol has a sustained effect, additive to that of a lipid-lowering diet; it can reduce total serum cholesterol and cause xanthoma regression even in patients with receptor-defective homozygous familial hypercholesterolemia. It is effective when used alone and has an additive effect when combined with resins or nicotinic acid. Compared with many other lipid-lowering medications, it is well tolerated. Although the combination of probucol and clofibrate may cause a significant decrease in high density lipoproteins, there is no evidence that this decrease carries any adverse consequences for the underlying disease process.

Role of risk factor management in progression and regression of coronary and femoral artery atherosclerosis

The results of 3 recently completed studies usher in a new era in the treatment of coronary atherosclerosis and its sequelae. In aggregate, these results show that reductions in low density lipoprotein (LDL) cholesterol or reductions in the ratio of total to high density lipoprotein (HDL) cholesterol by either diet or drugs or both are effective in primary and secondary prevention of coronary artery disease (CAD). In the Lipid Research Clinics' Coronary Primary Prevention Trial, reducing levels of LDL cholesterol, regardless of whether the primary intervention was diet or drug, correlated with a reduction in CAD events. In the National Heart, Lung, and Blood Institute's Type II Coronary Intervention Study, CAD progression at 5 years was inversely related to a change in the ratio of HDL cholesterol to total cholesterol. In the Leiden Intervention Trial, cessation of coronary artery atherosclerotic lesion growth correlated with the ratio of total cholesterol to HDL cholesterol. Several trials now under way will test the effects of much more substantial reductions of LDL cholesterol (up to 50%) and increments in HDL cholesterol (up to 25%) on interrupting the progression or inducing the regression of coronary artery atherosclerosis. Even small reductions in the progression of coronary artery lesions or induction of their regression should produce major reductions in morbidity and mortality from CAD. The importance of secondary prevention also extends to patients after coronary artery bypass surgery, because the likelihood of graft occlusion is likewise related to the patient's lipid profile. Further, the importance of primary prevention of atherosclerosis through modification of lipids and lipoprotein cholesterol in the first-degree relatives of young victims of atherosclerosis cannot be overemphasized.