Angina and Low Blood Pressure

What is Angina?

Angina, also known as angina pectoris, is a condition defined by chest pain ¹ Restricted blood flow to the heart can lead to heart disease and heart failure. When a patient with angina continues to live ordinarily without a diagnosis or correct treatment, the patient is at risk of myocardial infarction (also known as a heart attack). There are 3 different types of angina: stable angina, unstable angina and microvascular angina. Stable angina occurs when the heart is working harder than usual due to restricted blood flow and therefore the signs of angina appear when the patient is undergoing physical stress. Unstable angina, instead, does not follow a pattern and can happen without physical exertion, therefore making this angina the most dangerous kind. Microvascular angina, is caused by blockage in the small arteries which bring oxygenated blood to the heart. 

Signs and Symptoms

Signs of angina may include:

• Squeezing of the chest
• Pressure on the chest
• Heaviness of the chest, like a heavy weight has been placed on your chest
• Tightness of the chest
• Pain in the chest

Women may also experience a sharp stabbing pain in the chest which may spread to your arms, neck, jaw or back. 

This type of pain can result from physical exertion, extreme weather or stress but will stop after a few minutes of resting. ²

Causes and Risk Factors

The main lifestyle risk factors that increase the probability of developing angina include:

• An unhealthy diet with high cholesterol 
• Lack of exercise 
• Smoking 
• Alcohol consumption
• Stress

Other risk factors include increase in age, family history of coronary heart disease or atherosclerosis, a condition in which fatty plaque accumulates in the main arteries leading to the heart.

Angina can be caused by two types of coronary heart diseases: coronary artery disease (CAD) and coronary microvascular disease (CMD). 

CAD occurs when plaque (a substance made from cholesterol, fat, calcium and other substances) builds up in the main arteries that feed oxygenated blood to the heart and therefore makes the arteries narrower and can end up blocking them completely. By making the arteries narrower, plaque buildup restricts the blood supply to the heart and puts the heart muscles under heavy stress.  Additionally, the plaque can break open and cause a blood clot to form in the artery, therefore blocking the coronary arteries partially or even completely. 

CMD affects the smaller arteries that branch off the main coronary arteries; blockage of these smaller arteries can cause microvascular angina. 

Diagnosis

In order to be diagnosed with angina, an electrocardiogram (ECG) can be used. An ECG is a test which tests the heart rhythm and electrical activity by measuring the electrical impulses created by your heart each time it beats. If the test shows any irregularities in the electrical signals of the heart, it could be a sign of coronary heart disease which indicates thatthe coronary arteries are blocked due to plaque buildup. ECGs can also be used to diagnose a heart attack,  which is when the heart’s blood supply is completely cut off. ² For angina it is common to use a stress/exercise ECG as this ECG will be carried out whilst the patient conducts some form of physical exercise (normally on an exercise bike) since angina can be triggered by physical exertion or stress. 

Angina can also be diagnosed by using a coronary angiography which is another type of scan where X-rays are used to see the heart’s blood vessels; the blood vessels can be seen because a dye marking out the arteries and veins is injected before using the X rays. This procedure can be used in order to observe whether there is any restriction to the blood flow in the main coronary blood vessels³ . 

Management and Treatment

Angina treatment is used to reduce the frequency of angina attacks and the chance of heart attacks. Glyceryl trinitrate (GTN) is given to patients with stable angina to stop angina attacks; the patients must stop doing what they were doing before the attack, rest and take GTN - if after the first 5 minutes the medicine hasn’t had an effect, the patient may take a second dose. GTN can also be used in a preventive way by taking a dose before taking part in exercise. As well, patients suffering from angina must take another medicine which could be beta blockers or calcium channel blockers. Beta blockers make the heart beat slower and with less force whereas calcium channel blockers relax the arteries and therefore enable more blood to reach the heart. On the other hand, to avoid heart attacks (as opposed to angina), patients may be given statins to reduce the cholesterol level or a low doses of aspirin to prevent blood clots². 

Prevention

In order to prevent the development of angina, it is necessary to reduce the heart disease risk factors which have been mentioned above. Some ways of reducing angina include:

• Quit smoking
• Maintain a healthy diet low in cholesterol, fat and salt
• Maintain a healthy weight 
• Live an active lifestyle, by incorporating some form of daily physical activity 
• Reduce stress
• Consume omega-3 fatty acid-rich foods like salmon

It is also important to see the doctor frequently if you have a family history of coronary heart disease or atherosclerosis. 

Complications

If stable angina remains untreated, it can lead to more complicated conditions including heart attacks, heart failure, sudden death caused by abnormal heart rhythms, and unstable angina. Therefore, it is essential to contact your doctor if you have any symptoms of stable angina as these are life threatening conditions⁴.

The survival rate of angina patients depends on when the treatment is administered and the type of angina the patient suffers from, as well as the the number of ischaemic blood vessels in a patient. The 12-year survival rate of patients with normal coronary arteries was 91%, compared with 74% for those with one-vessel disease⁵ . 

Low Blood Pressure

Causes of Low Blood Pressure 

Low blood pressure, or hypotension, can be as a result of multiple conditions. These include (6):

• Pregnancy
• Heart or valve conditions
• Endocrine disorders
• Dehydration
• Blood loss
• Lack of nutrients in the diet 
• Diabetes

Effects of Low Blood Pressure on the Body

Signs and symptoms of low blood pressure may include blurred vision, lightheadedness, rapid shallow breathing, fading of the skin’s coloration, weak and rapid pulse⁶. 

Effect of Low Diastolic Blood Pressure on Angina and Heart Disease Risk

Low diastolic blood pressure is associated with angina in patients with chronic Coronary Artery Disease because CAD patients with low blood pressure have an increased risk of myocardial infarction (heart attack)⁷ . The study⁷ showed that because blood pressure treatment like ACE inhibitors can sometimes be used to treat angina (as hypertension makes angina more dangerous). Clinicians should ensure the CAD patients are not given medication to lower their blood pressure as this could increase the risk of heart attack. 

When to See a Doctor

Seek advice from a doctor if the low blood pressure causes symptoms like loss of consciousness, mental confusion, weak and rapid pulse, rapid breathing patterns. 

Summary

Angina is the body’s warning that something is severely wrong with circulation to the heart, and can also act as a warning sign for more severe conditions like heart attacks, heart failure or even death due to arrythmia. As a result, it is essential to understand the symptoms of the disease and to seek help if one experiences any of these symptoms, as well as ensuring we maintain a healthy diet and lifestyle. Additionally, if a patient with chronic CAD has low blood pressure, they should ensure to monitor their health more as they may be more at risk of developing angina or having a heart attack.