High-Density Lipoprotein and Cardiovascular Risk

Abstract

L ow serum levels of highdensity lipoprotein (HDL) are commonly encountered in patients with coronary artery disease (CAD). An example of this type of patient is a 42-year-old white man with a history of sudden-onset angina secondary to a 90% obstructive lesion along the proximal left anterior descending coronary artery. The family history was significant for his father, who died of a myocardial infarction (MI) at age 44 years. The patient underwent percutaneous transluminal angioplasty with stenting but developed in-stent restenosis. He underwent cutting balloon angioplasty and brachytherapy and was asymptomatic for approximately 6 months. The stent then developed a high-grade occlusion with recurrence of angina, and the patient required single-vessel bypass surgery.The patient's baseline serum lipid profile revealed low-density lipoprotein (LDL) 128 mg/dL, HDL 27 mg/dL, and triglycerides 92 mg/dL. His lipoprotein(a), C-reactive protein, and homocysteine levels were normal. He was not hypertensive, had no impairment of glycemic control, and did not smoke. With a combination of simvastatin 40 mg and niacin (Niaspan; Kos Pharmaceuticals) 1000 mg daily, the patient's lipid profile improved, with LDL 78 mg/dL, HDL 43 mg/dL, and triglycerides 60 mg/dL. Follow-up stress testing demonstrated normal myocardial perfusion, and the patient has been asymptomatic for 2 years. HDL as an Independent Risk Factor for CADWith few exceptions, low HDL is an independent risk factor for CAD in case-control and prospective observational studies. In contrast, high HDL levels are associated with longevity and are protective against the development of atherosclerotic disease. In the Framingham Study, risk for CAD increases sharply as HDL levels fall progressively below 40 mg/dL. 1 In the Quebec Cardiovascular Study, for every 10% reduction in HDL, risk for CAD increased 13%. 2 Many clinicians believe that low HDL is associated with increased CAD risk because it is a marker for hypertriglyceridemia and elevated remnant particle concentrations. The Prospective Cardiovascular Münster Study, however, demonstrated that the increased risk associated with low HDL is independent of serum triglyceride levels. 3 In the United States, low HDL is present in 35% of men and 15% of women. 4 Given the evolving epidemic of obesity, diabetes mellitus, and metabolic syndrome, the prevalence of low HDL will continue to rise. In one study, low HDL occurred in approximately 63% of patients with CAD. 5 Low HDL is associated with increased risk for MI, stroke, sudden death, restenosis after angioplasty, and severe premature atherosclerotic disease in the proximal left main coronary artery. 6 -9 In one autopsy series, the average total cholesterol:HDL ratio and HDL level in men who died suddenly during exertion were 8.2 and 36 mg/dL, respectively. 10

Effect of garlic supplement in the management of type 2 diabetes mellitus (T2DM): a meta-analysis of randomized controlled trials

“…The difference in onset time of garlic on blood liquids may be caused by the different measured time and limited sample size in the study, thus enough courses of garlic administration may be crucial for blood liquid regulation. Low level of HDL is an independent risk factor for coronary artery disease, and increased level of HDL is protective against atherosclerotic disease [30]. Together with its confirmed anti-hypertensive effects, garlic was supposed to lower the risk of macrovascular and cardiovascular events in specific T2DM patients [9].…”

Improvement in Biochemical Parameters in Patients with Type 2 Diabetes After Twenty-Four Sessions of Aerobic Exercise: A Randomized Controlled Trial

“…Although aerobic exercise did not alter the amount of HDL in the aerobic group, the lack of exercise in the control group showed significantly decreased HDL. A decrease in 10 mg HDL in the control group, according to the study of Toth, resulted in an increase of 13% in coronary heart disease (30). Constant HDL, in the exercise group, could be attributed to the normal range of the lipid profile.…”

Functionally Defective High Density Lipoprotein is Pro-Oxidant: a Deviation from Normal Atheroprotective Character

“…[17]. High-density lipoproteins are recognized for their many atheroprotective functions [4]. It has also been implicated in the inhibition or the regression of atherosclerosis in humans and experimental animals [33].…”

“…CHD has a multi-factorial etiology, with many of the risk factors being influenced by lifestyle. Several prospective epidemiological studies have found that low level of serum high-density lipoprotein-cholesterol (HDL-C) constitute a strong, independent risk factor for coronary heart disease [3][4][5]. HDL protects against atherosclerosis by regulating cholesterol efflux from tissues, modulating inflammation, providing antioxidant, vasoprotective, antithrombotic and anti-infectious properties [6].…”