When blood and oxygen flow to your heart is compromised, you develop chest pain. We term it unstable angina. It may precede a myocardial infarction (heart attack). Unlike other types of angina, this is an emergency: any delay in management may be fatal.
The principal cause of unstable angina is a narrowed coronary artery. Usually, an atheroma builds up in one of the branches of the coronary artery over time. The atheroma disrupts the vessel wall (endothelial injury). When this occurs, a blood clot forms over this plaque, cutting off blood and oxygen supply to the myocardium (heart muscle) supplied by this artery. A series of biochemical changes occur as the cardiac muscle respires in the absence of oxygen. Chest pain occurs. If this goes untreated, there may be total occlusion of the vessel and irreversible death of the myocardium culminating in a fatal myocardial infarction. On rare occasions, coronary arteries develop spasms that cause a transient impediment in blood and oxygen flow.
Unstable angina is a devastating heart disease you can prevent. Why? It is responsible for more than 33% of deaths among people 35 years or older, occurring more in men than women till after 75 years when the gap narrows. Besides a male predilection, family history, and autoimmune diseases, all the risk factors associated with unstable angina are modifiable. They include diabetes, hypertension, obesity, smoking, alcohol abuse, HIV, drug abuse, chronic kidney disease, and anaemia.
You may have narrowed coronary arteries with no symptoms until you suddenly increase the heart’s oxygen demand. These factors may increase the demand: cardiac arrhythmias, fever, high blood pressure, cocaine use: aortic stenosis, arteriovenous shunts, thyrotoxicosis, anaemia, congestive heart failure, and pheochromocytoma.
Classically, you will develop chest pain and shortness of breath. Such pain may be perceived as chest heaviness, tightness, burning that radiates to the neck, jaw, or left arm. You may feel dizzy, nauseated, sweaty, and experience palpitations. Important to note, this pain will worsen with exertion but with slight relief upon resting. Nitroglycerin or aspirin may alleviate it but won’t resolve it completely. It may not be the sentinel episode; however, it may be worse than the previous ones.
Upon arrival at the hospital, the clinician will take your history and examine you. Don’t be surprised that they may find nothing in their exam except that you may be experiencing laboured breathing and have an increased heart rate. In a few cases, you may have abnormal breath sounds (rales) due to fluid collection within the lungs (pulmonary oedema).
Unstable angina may put you in a dire situation if the clinicians find the following features upon examining you: distended neck vessels, abnormal heart sounds (S3, S4, new murmurs), and low blood pressures (hypotension).
Electrocardiography is the most important investigative tool in unstable angina. It guides clinicians on the next step of management. If it confirms unstable angina, you will need drugs to disintegrate the clot within the coronary arteries or a percutaneous coronary intervention (PCI) as clinicians avail a catheterisation lab for further evaluation.
You will have a complete blood count to rule out anaemia and abnormal platelet levels: serum electrolytes, cardiac enzymes, clotting studies, and chest x-ray with or without a chest CT scan.
Restoring blood flow to the myocardium is the main objective in this situation. You will receive a comparative aspirin dose, nitroglycerin, clopidogrel, oxygen, and low molecular weight heparin. You may also get a beta-blocker drug to decrease the heart’s energy demand through blood pressure control. You may need a cholesterol-lowering drug (statin).
It is imperative to note that you can take aspirin on your way to the hospital as it may save your life. Upon stabilisation, you may need an operation to open the coronary arteries. They may include coronary artery bypass graft (CABG), stenting, or balloon angioplasty.
Treating unstable angina is a costly venture. Prevention is free. Choose wisely. You should lose weight, exercise regularly: quit smoking, don’t abuse alcohol, and if you are at risk, know when to visit a clinician for a medical check-up. Seek medical attention for any chest pain that is (not) relieved by nitroglycerin.
For more information, read this article.