Endothelial dysfunction: implications for therapy of cardiovascular diseases.

OBJECTIVE: To review current literature regarding endothelial dysfunction in cardiovascular diseases and examine implications of these findings for the treatment of various cardiovascular disorders. DATA SOURCE: A MEDLINE search of basic science articles pertinent to understanding the role of the endothelium in the atherosclerotic process and of clinical trials examining the presence and treatment of impaired endothelium-dependent vascular relaxation was conducted. STUDY SELECTION: Selected basic science articles and reviews were included to explain the foundation for subsequent clinical trials. All clinical trials examining the treatment of impaired endothelium-dependent vascular relaxation were reviewed. DATA SYNTHESIS: Endothelial dysfunction characterized by impaired endothelium-dependent vascular relaxation is an early physiologic event in atherogenesis. Endothelial dysfunction in peripheral vasculature serves as a marker for impairment in coronary arteries. Techniques for measuring endothelium-dependent vascular relaxation are specific and have a high positive predictive value for coronary artery disease, but low sensitivity. Various pharmacologic agents have been used in an attempt to improve endothelial function, but only lipid-lowering agents and estrogen supplementation have been shown to improve endothelium-dependent vascular relaxation consistently. Treatments used in patients with heart failure or hypertension fail to demonstrate consistent improvement. CONCLUSIONS: Endothelial dysfunction serves as a marker for cardiovascular disease, but pharmacologic treatment does not consistently restore normal endothelial function. Nevertheless, some of these agents are known to have positive clinical outcomes. Future research using these techniques will provide greater insight into the effects of many commonly used therapies for cardiovascular disease on the pathobiology of endothelial dysfunction.

Bisoprolol: is this just another beta-blocker for hypertension or angina?

OBJECTIVE: To review the pharmacology, pharmacokinetics, and clinical experience with bisoprolol and make recommendations regarding its potential clinical usefulness, as well as considerations for formulary inclusion. DATA SOURCES: Reference citations were sought from Index Medicus and Science Citation Index. Data were collected from abstracts and articles describing experimental studies or blind clinical trials. STUDY SELECTION: Studies designed in a randomized, blind, and placebo-controlled manner were emphasized. Studies also were included if bisoprolol was evaluated comparatively with other agents in a randomized, blind fashion. DATA EXTRACTION: Data from human studies published in English were evaluated. Studies were assessed by sample size and the clarity of descriptions of methods and results. DATA SYNTHESIS: Bisoprolol reduces systolic and diastolic blood pressures in patients with hypertension for a 24-hour dosing interval and is associated with beneficial hemodynamic effects in patients with myocardial ischemia. It is devoid of intrinsic sympathomimetic activity and membrane-stabilizing effects at therapeutic dosages. In patients with hypertension, bisoprolol diminishes plasma renin activity, platelet aggregation, effective renal plasma flow, and creatinine clearance. Bisoprolol has minimal effects on glucose tolerance and plasma lipid profiles. Monotherapy with bisoprolol is as effective as with atenolol, nitrendipine, or nifedipine. Low-dose combination therapy with hydrochlorothiazide is at least as effective as either bisoprolol or hydrochlorothiazide alone. Preliminary experience in the management of angina pectoris suggests that bisoprolol is at least as efficacious as atenolol or verapamil. Thus far, reported adverse effects are similar to those of other beta-blockers. No clinically important drug interactions have been reported at this time.