How Does Coronary Heart Disease Affect The Body?

Introduction

Coronary Heart Disease (CHD) is a disease that affects coronary arteries (a type of blood vessel) in the heart. Coronary arteries provide blood to the heart muscle (myocardium), which is important in maintaining cardiovascular health.¹

CHD can be a progressive disease that takes years to develop due to several modifiable and non-modifiable risk factors. Initially, the inner lining of coronary arteries starts to develop fatty deposits and cholesterol, which eventually build up to form plaque, a condition known as atherosclerosis. Once this happens, the arteries narrow, reducing blood flow, oxygen, and nutrients to the heart.

There are several symptoms associated with this and other complications may result, including a heart attack that can be fatal. This condition can impact the heart and other areas of the body significantly. Therefore, understanding the severity of CHD is crucial to avoiding it through diagnosis and treatment, which will all be explained in more detail in this article.¹

Symptoms of CHD

There are a wide range of symptoms experienced by patients with CHD, depending on how severe their disease is. A lack of oxygenated blood in the heart can lead to the following symptoms:

• Angina (chest pain)
• Shortness of breath
• Fatigue

It is possible, however, to suffer a heart attack when oxygenated blood is completely cut off to the heart. In addition to those listed above, there are other symptoms associated with a heart attack:

• Weakness
• Pain or discomfort across the body (in the shoulders, arms, neck, jaw or back)
• Heartburn 
• Nausea 
• Cold sweats
• Lightheadedness
• Sudden dizziness^, 

Although, in some patients, CHD symptoms may remain silent until a heart attack or other complications arise.

Effects of CHD on the heart

CHD may also cause other complications in the heart, which should be considered. Following are examples of cardiovascular complications:

Angina

Angina is already a symptom of CHD, but as it worsens it can become a complication in patients. It is experienced as a result of the narrow coronary arteries, reducing the oxygenated blood to the heart. This form of chest pain causes tightness and pressure, but symptoms can differ between men and women.

There are two main types of angina - stable and unstable.

• Stable angina - Pain that occurs in a pattern and lasts for a few minutes while exercising or stressed, can be relieved by rest or medication
• Unstable angina - Pain that is longer lasting and stronger, and requires immediate medical attention 

Heart attack (myocardial infarction)

Plaque can build up from atherosclerosis, as previously described, or blood clots can form. The plaque and blood clot can rupture once the coronary artery has been completely blocked. As a result, oxygenated blood flow to the myocardium is reduced, resulting in myocardial death which ultimately results in a heart attack. 

Heart failure

Another complication is heart failure, which is caused by narrowed coronary arteries and high blood pressure which makes the myocardium weak and stiff. The heart is unable to pump blood effectively because of this difficulty.

Arrhythmias (irregular heartbeats)

Arrhythmias are irregular heartbeats caused by a change in heart signalling when the heart does not receive enough blood. 

The main types of arrhythmias include:

• Tachycardia - fast heartbeat 
• Bradycardia - slow heartbeat 
• Atrial fibrillation - rapid irregular heartbeats

Systemic effects of CHD on the body

As well as causing heart complications, CHD can have multiple effects on the body in other ways too. CHD affects the following:

Impact on the lungs

In heart failure, the blood backs up because it is not properly pumped around the heart, resulting in fluid buildup in the lungs. Shortness of breath and breathing difficulties result from this.² Research indicates that lung dysfunction increases cardiovascular risk, although the reasons for this are unclear.³

Impact on the kidneys

In CHD patients chronic kidney disease is common as reduced blood flow through the coronary arteries affects the kidneys’ function. This can worsen the symptoms of heart failure in patients from this.²

Impact on the brain

Reduced blood flow and clot formation can increase the risk of a stroke. From this brain function is impacted such as memory loss due to the reduced oxygen the brain is receiving.

Research studies have found that it’s important to prevent CHD and its complications to delay the risk of cognitive decline and memory, further studies need to be conducted to confirm this.⁴

Risk factors of CHD

CHD can occur due to several factors that are either modifiable or non-modifiable.¹ Patients are more likely to develop CHD with an increased number and more serious risk factors.

Modifiable risk factors include: 

• Smoking 
• Hypertension (high blood pressure)
• High cholesterol
• Diabetes
• Poor diet 
• Lack of physical activity
• Obesity
• Stress
• Alcohol
• Lack of sleep

Since these factors are in the patient's control, if they are at risk of CHD, it is necessary to manage them to prevent further complications in the heart, body, and death.

Non-Modifiable Risk Factors include: 

• Age
• Gender
• Family history
• Genetics

However, these factors are out of a patient's control which contributes to increasing the likelihood of developing CHD. 

The presence of inflammatory markers also contributes to CHD development. A high level of C-reactive protein (CRP), an inflammatory molecule, is linked to coronary heart disease and other cardiovascular diseases, according to research.⁵

Through the American Heart Association portal, patients can predict their risk for developing CHD, allowing them to make lifestyle changes where necessary and know their health status.¹

Diagnosis of CHD 

To diagnose CHD, healthcare professionals will ask patients about their medical history and any symptoms they have been experiencing. Various tests will be required to determine whether the patient has or is at risk of developing CHD if they experience any of the symptoms previously described above.

The following methods can be used to diagnose CHD: 

• Electrocardiogram (ECG) - Monitors the electrical activity of the heart to detect abnormal heart rhythms (arrhythmias) and muscle damage
• Stress tests (Exercise ECG) - Shows how well the heart performs when walking on a treadmill and being monitored by an ECG
• Coronary angiography - Involves inserting a catheter (a long tube) through which a dye is passed to detect blockages or narrowings of coronary arteries
• Echocardiogram - An ultrasound of the heart showing blood flow, the condition of its structures such as its valves, and how well it pumps
• Blood tests - For blood glucose, cholesterol, and CRP levels
• CT scan
• MRI scan 
• PET scan 

The purpose of these methods is to identify CHD early, so that treatment strategies tailored to a patient's condition can be implemented before the condition progresses and puts the patient at risk for complications or death. 

Treatment of CHD

In the early stages of CHD treatment, modifiable risk factors must be controlled. Patients have shown improvement in this aspect of their care.¹

They can make these changes by: 

• Eating a healthier diet
• Exercising more often 
• Getting enough sleep
• Managing stress
• Controlling blood pressure, cholesterol, and blood glucose levels
• Stopping smoking

In combination with these lifestyle changes patients are given medications. These medications can reduce the symptoms of CHD and the risk of other issues occurring. Different medicines can be used for CHD with different functions depending on what's best for the patients.

The following are medications CHD patients may be given: 

• Statins (help to lower cholesterol)
• Anticoagulants (blood thinning prevent blood clots) 
• Beta-blockers (lower blood pressure)
• Nitrates (widen blood vessels)
• Angiotensin-converting enzyme (ACE) inhibitors/Angiotensin-2 receptor blockers (ARBs) (lowers blood pressure and prevent blood vessels narrowing)
• Calcium channel blockers (reduce blood pressure and widen arteries) 

These medications can have side effects, so it’s important for healthcare professionals to give the right one to suit the patient.

In severe cases, CHD may have progressed to a point where even medications won’t work, so surgeries may be carried out to fix a blocked artery and improve blood flow.

Surgical procedures that can be carried out:

• Coronary angioplasty/stenting (also known as Percutaneous Coronary Intervention) - It involves a catheter with a balloon attached to improve blood flow through narrowed or blocked coronary arteries. A wired mesh will then be inserted to keep the artery widened
• Coronary artery bypass grafting (CABG) - This type of surgery involves taking healthy arteries/veins from elsewhere in the body to replace the blocked artery with a new pathway to the heart

CHD patients should undergo these surgeries when their condition worsens as they prevent the risk of complications. Whenever these surgeries are performed, these patients must be monitored, assessed for recovery, and detected for complications if they arise.

Summary

Coronary artery disease is a condition that causes the coronary arteries to narrow or become completely blocked. This reduces oxygenated blood flow to the myocardium resulting in complications affecting the heart and other parts of the body. It is a multifactorial disease with non-modifiable and modifiable factors. Therefore, patients should be aware that controlling certain factors can reduce the risk of CHD and its complications on the body. Through early diagnosis, treatment, and prevention, patients could avoid long-term issues and death.