Drug Treatment of Coronary Artery Disease
(See also Overview of Coronary Artery Disease.)
The heart muscle needs a constant supply of oxygen-rich blood. The coronary arteries, which branch off the aorta just after it leaves the heart, deliver this blood. Coronary artery disease that narrows one or more of these arteries can block blood flow, causing chest pain (angina) or an acute coronary syndrome. In an acute coronary syndrome, sudden blockage in a coronary artery greatly reduces or cuts off the blood supply to an area of the heart muscle (myocardium). The lack of blood supply to any tissue is termed ischemia. If the supply is greatly reduced or cut off for more than a few minutes, heart tissue dies. A heart attack, also termed myocardial infarction (MI), is death of heart tissue due to ischemia.
There are many different reasons doctors give drugs to people with coronary artery disease:
To relieve chest pain by reducing the heart's workload and widening arteries (nitrates, morphine)
To prevent angina and acute coronary symptoms from occurring (beta-blockers, calcium channel blockers, sometimes a newer drug, ranolazine)
To prevent and reverse coronary artery narrowing from atherosclerosis (angiotensin-converting enzyme [ACE] inhibitors, angiotensin II receptor blockers, statins, and antiplatelet drugs)
To open a blocked artery (clot-dissolving drugs, anticoagulants)
Calcium channel blockers prevent blood vessels from narrowing (constricting) and can counter coronary artery spasm. All calcium channel blockers reduce blood pressure. Some of these drugs, such as verapamil and diltiazem, may also reduce the heart rate. This effect can be useful to many people, especially those who cannot take beta-blockers or who do not get enough relief from nitrates.
Statins have long been used to help prevent coronary artery disease, but doctors have recently found that they also have short-term benefit for people with an acute coronary syndrome. Doctors give a statin to people who are not already taking one.
People who think they may be having a heart attack should chew an aspirin tablet immediately after calling an ambulance. If aspirin is not taken at home or given by emergency personnel, it is immediately given at the hospital. This therapy improves the chances of survival by reducing the size of the clot (if present) in the coronary artery. People may also be given other types of antiplatelet drugs such as clopidogrel or glycoprotein IIb/IIIa inhibitors. Some people are given both aspirin and clopidogrel.
Clot-dissolving drugs (thrombolytic drugs) are given by vein (intravenously) to open the arteries if percutaneous coronary interventions cannot be done within 90 minutes after the person arrives at the hospital.
Most people are also given an anticoagulant drug, such as heparin, to help prevent the formation of additional blood clots.
Often, oxygen is given through nasal prongs or a face mask. Providing more oxygen to the heart helps keep heart tissue damage to a minimum.