Sublingual, intravenous, and oral nitrate preparations are used in the management of acute coronary syndromes. Most of the published data come from patients with myocardial infarction (MI), but the conclusions would apply to patients with unstable angina.
Benefits of nitroglycerin therapy include:
●Dilatation of large coronary arteries and arterioles (>100 millimicrons in diameter), which may lead to increased perfusion of ischemic zones.
●Dilatation of the venous system with decreased preload, reduction in ventricular volume, and a fall in pulmonary capillary wedge pressure. This effect is useful in patients with pulmonary congestion.
●Systemic arterial dilatation, which decreases afterload, also occurs but to a lesser degree. These changes lower wall stress and oxygen consumption and can reverse a restrictive filling pattern .