Relation of high levels of high-density lipoprotein cholesterol to coronary artery disease and systemic hypertension

Low levels of high-density lipoprotein (HDL) increase the risk for coronary artery disease (CAD).(1-3) In contrast, elevated HDL is considered a negative risk factor for ischemic heart disease, and HDL levels > 75 mg/dl have been associated with the "longevity syndrome."(1,4,5) This is not universally true, however. Very high levels of HDL have been found in patients with cholesterol transport protein deficiency, who unexpectedly have an increased incidence of CAD.(6,7) Recent data suggest that HDL particle size may also play a role in its cardiovascular protective effect. High levels of large HDL are associated with a decreased risk of CAD, whereas small HDL size may increase risk.(8-10) There have been no studies that have evaluated the risk of atherosclerotic disease in persons with extreme HDL elevation and systemic hypertension, and the impact of this combination.