Unstable angina treatment
Treatment of unstable angina focuses on deciding the degree of aggressiveness that the therapy should be according to the condition’s risk. The decision to admit to the ICU is guided by several indications that either point towards or ascertain the presence of myocardial infarction as:
- ECG changes as elevation or depression of ST-segment or evidence of ventricular arrhythmia due to bundle block. All these signs indicate myocardial ischemia that is enough to cause electrical abnormality, which is potentially fatal.
- Any sign of heart failure in development or potentially fatal.
- Elevated cardiac enzymes.
Unlike stable angina, the role of medical therapy in unstable angina is limited to decreasing the number of complications and temporarily controlling the condition’s progression. The invasive interventions remain the definitive therapy for unstable angina.
Medical therapy includes:
- Aspirin: Aspirin remains one of the most important and useful first measures in unstable angina. It prevents further aggregation of platelets, which is the main mechanism by which unstable angina occurs. It also prevents the formation of new clots. With that said, special care should be taken regarding patients who have any bleeding tendencies.
- Other antiplatelet drugs: as Clopidogrel and Ticagrelor may be used instead of aspirin.
- Anticoagulants: A blood clot is formed of platelets and fibrin. Fibrin is formed through a coagulation cascade that starts with the activation of coagulation factors, and while antiplatelets function on platelets alone, anticoagulants act on the coagulation cascade itself. Examples include drugs taken parenterally by injection as heparin and low molecular weight heparin, the latter being the more widely used, and those taken orally as Warfarin. Injectable preparations have a short duration of action, and therefore are used in emergency settings, while oral drugs are primarily used for long-term follow-up therapy.
- Lipid-lowering drugs: Although the main event is the formation of a blood clot, the condition overall is related to atherosclerosis and lipid deposition into the arterial walls. Therefore, the lowering of blood cholesterol levels is paramount in the long-term management of the condition. The most commonly used family of lipid-lowering drugs are called statins, and they act mainly by inhibiting the formation of cholesterol in the body -which is the main source of cholesterol-. In recent studies, it was also proven that they reverse atherosclerosis.
- Beta-blockers: The list of beta-blockers’ uses has expanded recently to include coronary artery diseases from stable angina to myocardial infarction. Doctors widely use such a family because they have multiple effects, most of which are beneficial for cases of supply-demand mismatch in angina. They lower the heart rate and blood pressure and are antiarrhythmics. All the previous effects counteract the sympathetic system overactivity seen in angina or coronary artery disease cases in general, which is one of the leading causes of heart failure in coronary artery diseases. They also lower the demand for oxygen by decreasing the heart’s overall activity, thereby evening the equation of supply and demand. They have relatively few side effects and aren’t contraindicated except in some cases of heart failure.
- Nitrates: Nitrates are a family of drugs whose main action is vasodilation. In angina, they have a dramatic effect on the stable type and can relieve the attack in a matter of minutes. However, they are less effective in unstable angina, but this doesn’t mean that they are useless. They can still increase the caliber of the heart’s blood vessels, improving blood flow to the cardiac muscle to an extent, and lower blood pressure, decreasing the workload on the heart.
