Acute Coronary Syndrome

Acute Coronary Syndrome refers to the three types of disorders related to the arteries supplying blood to the heart (coronary arteries). In these disorders, the blood flow to the heart stops due to the blockage in the coronary arteries, which can result in damage and death of the heart tissue. It can cause symptoms like chest pain, shortness of breath, nausea, vomiting, sweating, etc. The symptoms may be atypical or less evident in people with Diabetes Mellitus, women, and old age. It is a life-threatening condition that needs prompt diagnosis and treatment. 

Your heart is composed of muscles that contract to pump blood throughout the body. These muscles themselves are fed by the blood vessels called the coronary arteries. Acute coronary syndromes are caused by a partial or complete blockage of the coronary vessels due to atherosclerosis. Atherosclerosis refers to the deposition of small fatty deposits (atherosclerotic plaque) in the blood vessels causing obstruction and impedance to the blood flow.  With time, this fatty deposit causes injury in the lining of the blood vessels, attracting platelets and other coagulation factors leading to the formation of a blood clot called thrombus that can increase in size gradually until it results in complete blockage of the artery. 

Three different types of conditions come under the umbrella term of acute coronary syndrome based on the duration of symptoms, blood test results, and the presence or absence of ECG changes (ST elevation).

• Unstable angina: Unstable angina is caused by an active unstable atherosclerotic plaque, which attracts platelets, undergoes thrombosis, and increases in size day by day, ultimately causing a complete blockage. Its cardinal features are worsening, severe, or new-onset chest pain that starts to occur even at rest and is unpredictable. Its duration is usually less than 30 minutes. It does not cause cell death by itself, but it is an emergency as it can lead to a heart attack.
• Non-ST-elevation myocardial infarction: It is a heart attack (myocardial infarction) that results in the death of the heart tissue. It causes an increase in the cell death markers in the blood, which can be detected with blood tests, but it does not cause ECG (EKG) changes. The ECG may be normal or show signs of compromise but does not display the hallmark of a heart attack which is ST elevation.
• ST-elevation myocardial infarction: It is a heart attack (myocardial infarction) that results in the death of the heart tissue. It causes an increase in the cell death markers in the blood, which can be detected with blood tests and show typical ECG changes (ST elevation).

Having one or more of the following risk factors may increase your chances of developing Acute Coronary Syndrome.

• Family History: If any of your family members have a history of the early development of coronary artery disease (CAD), it predisposes you to the same.
• Smoking: Smoking tobacco increases the risk of coronary artery disease and angina.
• Diabetes Mellitus (DM): Suffering from DM predisposes you to angina.
• Hypertension: High blood pressure is an important risk factor. It can increase the resistance to blood flow and also can cause enlargement of the left ventricle of the heart.
• Abdominal Obesity: Increased waist circumference of >40 inches for men or >35 inches for women can put you at risk of developing coronary artery disease.
• High triglycerides, low HDL cholesterol: HDL cholesterol is the good cholesterol that saves you from developing CAD. Low HDL levels, along with high levels of triglycerides, can increase your chances of having CAD and Acute Coronary Syndrome.

Coronary artery disease is the most common type of heart disease prevalent in the USA. It affected 18.2 million adults and resulted in the deaths of  360,900 people in 2019.

It would be beneficial for you to be aware of the signs and symptoms of Acute Coronary Syndrome to act vigilantly and reach out for immediate care.

• Chest pain: Squeezing or heaviness in the center of the chest that can also be felt along the neck, jaw, back, and arm.
• Pain is felt during increased physical activity like climbing stairs or stress.
• You may also have nausea and vomiting.
• You may experience sudden extensive sweating, dizziness, and fainting.
• You may feel difficulty in breathing and may feel restless.

If you feel any of the above symptoms, seek immediate help by reaching out to your healthcare provider. He would take a quick history with a focused examination, and you may be advised to undergo one or more of the following tests for confirmation of acute coronary syndrome.

Electrocardiogram (EKG)

The electrical activity of the heart is measured in this fast procedure. Adhesive plugs (electrodes) are applied to the chest and the arms and legs in some cases. The electrodes are connected to a computer through wires, which shows findings. An Electrocardiogram can reveal whether the heart is beating excessively quickly, slowly, or not at all. The ECG may suggest that you've had or are experiencing a heart attack because wounded muscle tissue doesn't conduct electrical signals in a regular pattern.

Cardiac Enzymes

Increased amounts of specific proteins or enzymes found in cardiac muscle may be detected by blood testing. Injury to cardiac tissue caused by a heart attack may enable these proteins or enzymes to escape into the bloodstream over several hours.

Chest X-ray

 A chest X-ray can reveal the state of the lungs and the size of the heart and main blood channels. Lung disorders such as pneumonia or a collapsed lung can also be revealed by a chest X-ray.

Coronary catheterization

Coronary catheterization is a procedure that involves inserting a catheter into the coronary artery. This procedure allows doctors to see if there are any obstructions in the heart vessels. A catheter is a long, narrow, flexible tube placed into a blood channel and directed toward the heart, generally in the pelvis or forearm. Dye is delivered to the heart vessels via the catheter. The dye makes X-ray images and shows the arteries more effectively. This test is also known as a coronary angiogram.

The symptoms of acute coronary syndrome may mimic the symptoms caused by some other conditions;

• Myocarditis
• Esophageal spasm
• Acute Gastritis
• Panic attack
• Aortic stenosis
• Costochondritis
• Peptic Ulcer Disease

Immediate treatment of acute coronary syndrome focuses on relieving the obstruction in the artery to resrtore the blood flow and save the dying heart tissue, hence reducing the symptoms of pain and distress. Aftercare includes lifestyle changes, smoking cessation, treatment of the risk factors (like DM, and hypertension), and medications.

Medications

The following medications can be used;

Nitroglycerin: This allows blood to flow more freely through the restricted gaps as it relaxes the arteries.

Thrombolytic medications: These medications remove the clot that prevents blood from flowing to the heart muscle. Examples include Streptokinase, tPA, reteplase, etc.

Beta-blockers: They slow down the heart rate so the oxygen demand of the heart muscle is lessened. They also improve blood flow to the heart by relaxing the blood vessels. For example, Metoprolol, Propranolol.

Procedures

Angioplasty: This is the most common treatment for chest pain due to an obstruction in a heart artery. A catheter with a balloon on the tip is inserted into the blood channel, generally in the pelvis, and guided to the obstruction. The balloon is inflated to expand the vessel, then deflated and the catheter is removed. A tiny stent is frequently kept on the outside of the catheter's balloon tip. The stent expands and seals into position, keeping the artery intact.

Bypass Surgery: It is a procedure that involves the removal of a portion of a blood vessel from some other body part to establish a passage for blood to bypass the clogged artery.

The prognosis depends on how well the patient adheres to the treatment plan, the degree of obstruction, comorbid diseases, and their control.  Smoking cessation is very important. The outcome is usually good if a patient takes all his medicines regularly and adopts a healthy lifestyle. Otherwise, untreated angina will ultimately lead to a heart attack. 

Adopting the following lifestyle changes may prevent you from developing coronary heart disease and angina.

• Quit smoking
• Take a healthy balanced diet
• Perform some kind of exercise regularly
• Keep your health status in check by regularly getting assessed for Diabetes Mellitus, high blood pressure, etc.
• If you are suffering from any risk factors, keep it controlled by adhering to its treatment.
• Manage your stress by relaxation techniques.