Coronary Heart Disease Overview

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Questions and Answers

What primarily characterizes atherosclerosis in relation to its impact on arteries?

Decreased endothelial cell function leading to increased blood flow.

Congenital malformation of coronary arteries.

Inflammatory process causing lipid and fibrous tissue buildup. (correct)

Transient angina due to oxygen surplus in blood.

Which condition is most commonly associated with the highest incidence of coronary thrombosis?

Microvascular angina.

Acute Myocardial Infarction. (correct)

Coronary artery spasm.

Stable angina.

Which of these clinical manifestations is directly indicative of coronary artery obstruction?

Stable angina. (correct)

Coronary microvascular dysfunction.

Sudden cardiac death.

Variant angina.

What is a key underlying cause of microvascular angina?

Endothelial dysfunction in small coronary blood vessels. Signup and view all the answers

Which process is indicative of the final consequence of coronary artery disease leading to myocardial infarction?

Complete and permanent occlusion of a coronary artery. Signup and view all the answers

What is the impact of endothelial injury in coronary artery spasm?

Increased sensitivity to vasoconstrictors. Signup and view all the answers

Which of the following is a common outcome of a ruptured atheroma in relation to coronary thrombosis?

Immediate activation of the coagulation cascade and thrombus formation. Signup and view all the answers

Which of the following is NOT a major obstructive process associated with coronary heart disease (CHD)?

Myocardial hypertrophy Signup and view all the answers

Which of the following correctly describes myocardial ischemia?

A condition resulting from decreased blood flow to the heart muscle Signup and view all the answers

What is one of the primary clinical manifestations of coronary heart disease?

Angina pectoris Signup and view all the answers

Which therapeutic approach is commonly utilized in the management of coronary artery disease?

Administration of antiplatelet agents Signup and view all the answers

Which of the following processes contributes to coronary microvascular dysfunction?

Endothelial dysfunction Signup and view all the answers

What is the primary cause of myocardial ischaemia?

Imbalance between myocardial oxygen demand and supply Signup and view all the answers

Which of the following is NOT a characteristic of coronary heart disease?

Increased regional blood flow Signup and view all the answers

What is a sign of reversible tissue damage due to reduced blood flow?

Restoration of normal function upon improved blood flow Signup and view all the answers

Which statistic highlights the seriousness of coronary heart disease in the UK?

It accounts for over 68,000 deaths a year Signup and view all the answers

Aetiology of myocardial ischaemia includes which of the following?

Imbalance between oxygen demand and supply during exertion Signup and view all the answers

What is the primary determinant of myocardial oxygen demand?

Heart rate and contractility Signup and view all the answers

Which condition is often a precursor to developing coronary heart disease?

Atherosclerosis Signup and view all the answers

What is a common clinical manifestation of myocardial ischaemia?

Chest pain or angina Signup and view all the answers

What is one of the key social implications of coronary heart disease?

High morbidity and social costs Signup and view all the answers

Which factor contributes most to the progression of coronary artery disease?

Persistent endothelial damage Signup and view all the answers

Coronary microvascular dysfunction is not a recognized factor in the pathogenesis of Ischaemic Heart Disease.

False Signup and view all the answers

The understanding of the physiology and functional anatomy of the heart is essential for comprehending coronary heart disease.

True Signup and view all the answers

The clinical management of coronary heart disease excludes the consideration of atherosclerosis as an obstructive process.

False Signup and view all the answers

Ischaemic heart disease and coronary heart disease are interchangeable terms with identical definitions.

False Signup and view all the answers

Myocardial ischaemia can occur without the presence of cardiovascular diseases.

False Signup and view all the answers

What are the primary factors contributing to the pathogenesis of coronary heart disease?

Atherosclerosis, coronary thrombosis, coronary artery spasm, and coronary microvascular dysfunction. Signup and view all the answers

Describe the consequences of myocardial ischaemia on heart function.

Myocardial ischaemia can result in angina, reduced contractility, and can potentially lead to myocardial infarction. Signup and view all the answers

Identify two major clinical manifestations that arise from coronary heart disease.

Angina pectoris and myocardial infarction. Signup and view all the answers

How does coronary artery spasm contribute to myocardial ischaemia?

Coronary artery spasm narrows the arteries temporarily, reducing blood flow to the heart muscle and causing ischaemia. Signup and view all the answers

What role does a better understanding of cardiac physiology play in managing coronary heart disease?

A thorough understanding of cardiac physiology aids in identifying risk factors, diagnosis, and appropriate therapeutic strategies. Signup and view all the answers

Study Notes

Coronary Heart Disease (CHD) Overview

CHD is the leading cause of death worldwide.
CHD accounts for approximately 1 in 8 deaths in men and 1 in 14 deaths in women.
Approximately 2.3 million people are living with CHD in the UK, with 1.5 million men and 830,000 women affected.
Over 1.3 million people in the UK suffer from angina.
Approximately 1.4 million people have survived a heart attack, with 1 million being men and 400,000 women.
Over 100,000 people are admitted to hospital each year due to heart attacks.
Approximately 290 people are admitted to the hospital each day with a heart attack, or one person every 5 minutes.
Approximately 30% of people who suffer a heart attack do not survive.
One person dies from CHD in the UK every 8 minutes.

CHD in UK Economy

In 2018, CHD cost the UK economy approximately £12.7 billion.

CHD Pathophysiology

CHD occurs when there is a reduced blood flow to the heart due to obstruction or constriction of the coronary arteries.
The main cause of coronary artery obstruction is atherosclerosis, an inflammatory process that causes the buildup of plaque on the inner wall of the arteries.
Atherosclerosis usually begins developing in early life as a "fatty streak".
Other factors contributing to CHD include coronary thrombosis, coronary artery spasm, and coronary microvascular dysfunction.

Clinical Manifestations of CHD

Angina pectoris: chest pain that occurs when the heart muscle isn't receiving enough oxygen. There are different types of angina, including stable, variant, and microvascular angina.
Immediate or sudden cardiac death: this occurs when the heart suddenly stops beating due to a blockage in a coronary artery.
Acute coronary syndromes (ACS): this term encompasses unstable angina, which occurs when the heart muscle isn't getting enough oxygen, and acute myocardial infarction (AMI), or heart attack, caused by a complete blockage of a coronary artery.
AMI can be further categorized into two types: ST-segment elevation myocardial infarction (STEMI), which is caused by a complete blockage of a coronary artery; and non-ST-segment elevation myocardial infarction (NSTEMI) which is caused by a partial blockage of a coronary artery.

Atherosclerosis

Definition: A progressive, degenerative arterial disease characterized by the asymmetric deposition of lipids and fibrous tissue on the inside wall of arteries.
Cause: The most common cause of CHD, accounting for over 90% of cases.
Disease Process: Atherosclerosis begins as a "fatty streak" and progresses as:
- Low-density lipoprotein (LDL) deposits in the sub-endothelial space.
- LDL oxidation and monocyte recruitment into the sub-endothelial space occurs.
- Macrophages differentiate and take up oxidized LDL, forming foam cells.
- Smooth muscle cells (SMCs) migrate, proliferate, and de-differentiate, leading to the formation of a fibrous plaque or atheroma.

Consequences of Atherosclerosis

Impact on Coronary Function:
- Partial Coronary Occlusion: Can lead to stable angina.
- Endothelial/Vascular Dysfunction: Can lead to Coronary Artery Spasm.
- Ulceration/Rupture: Can lead to Coronary Thrombosis.

Coronary Thrombosis

Definition: The unwanted formation of a blood clot within a coronary artery.
Prevalence: Occurs in approximately 30-90% of ACS (unstable angina and evolving acute myocardial infarction, AMI).
Disease Process: Usually occurs on top of ruptured atheroma and involves platelet aggregation and the coagulation cascade.
Steps:
- Rupture or ulceration of an atherosclerotic plaque.
- Contact of blood elements with collagen and tissue factor.
- Platelet adhesion and activation.
- Activation of the coagulation cascade.
- Platelet aggregation and fibrin formation & deposition.
- Formation of a thrombus or blood clot.

Consequences of Coronary Thrombosis

Impact on Coronary Function:
- Complete and Permanent Occlusion: Can lead to ACS (STEMI).
- Subtotal or Intermittent Occlusion: Can lead to ACS (UA/NSTEMI).
- Thromboembolism: Can block blood flow in a distal artery.

Coronary Artery Spasm

Definition: A transient, spontaneous coronary vasoconstriction.
Causes: Can occur in normal coronary arteries, at mildly atherosclerotic sites, or during ongoing coronary thrombosis.
Underlying Cause of Variant Angina:
Disease Mechanisms:
- Local endothelial injury can increase reactivity to vasoconstrictors.
- Abnormal release of vasoconstrictors or an imbalance in local release of vasodilators and constrictors.
- Smooth muscle cell hypercontraction/hyper-reactivity.
Impact on Coronary Function:
- Subtotal or intermittent occlusion of a coronary artery.
- Complete focal occlusion of a coronary artery.

Coronary Microvascular Dysfunction

Definition: Damage to the inner walls of the small coronary blood vessels (coronary microvasculature), leading to microvascular spasms, decreased blood flow, and reduced coronary flow reserve.
Causes: The underlying cause of microvascular angina.
Disease Mechanisms:
- Microvascular Remodeling: Luminal narrowing of intramural arterioles and capillaries, leading to microvascular obstruction.
- Endothelial Dysfunction: Impaired vasodilator response and reduced coronary blood flow during exercise or stress.
- Functional abnormalities of the smooth muscle cells that regulate arteriolar tone.
Impact on Coronary Function:
- Reduced coronary flow reserve and increased risk of myocardial ischemia.
- INOCA (Inadequate Coronary Flow Reserve): This leads to a lack of oxygen and nutrient supply to the tissue, and a lack of removal of metabolic waste.
- Reversible and irreversible tissue damage may occur.
- The extent of tissue damage is determined by the duration and severity of the ischemia.

Myocardial Ischemia

Myocardial ischemia describes a decrease in regional blood flow to the heart muscle.
Myocardial ischemia defines an imbalance between myocardial supply and demand.
This can be caused by an increase in myocardial oxygen demand (exertional demand ischemia) or a decrease in myocardial oxygen supply (non-exertional supply ischemia).

Determinants of Myocardial Oxygen Demand and Supply

The factors that affect myocardial oxygen demand include:
- Heart rate
- Contractility
- Pre-load (volume of blood in the ventricle at the end of diastole)
- After-load (resistance that the heart must overcome to pump blood out of the ventricle)
The factors that affect myocardial oxygen supply include:
- Coronary artery blood flow
- Coronary artery blood oxygen content
- Oxygen extraction by the myocardium

CHD Overview

Coronary Heart Disease (CHD) is a major public health concern, being the single leading cause of death worldwide and one of the leading causes of death in the UK.
CHD refers to pathological conditions characterized by reduced or inadequate blood flow to the heart, usually due to an obstructive or constrictive disease of the coronary arteries.
Myocardial Ischaemia is reduced regional blood flow to the heart. This imbalance between myocardial oxygen demand and supply can be due to exertional demand ischaemia or non-exertional supply ischaemia.
The prevalence of CHD is high, with over 2.3 million people currently living with CHD in the UK, contributing to significant morbidity and social cost.
The BHF HeartStats Report reveals that CHD accounts for over 68,000 UK deaths a year.
CHD costs the UK economy around £12.7 billion annually.
Atherosclerosis: This is the most common cause of CHD (over 90%), and it involves the deposition of lipids and fibrous tissue on the inside wall of arteries.
The disease process of atherosclerosis: It is an inflammatory process that begins early in life as a "fatty streak".
Coronary thrombosis: This is the formation of a blood clot within coronary arteries, and it's often seen in unstable angina and evolving acute myocardial infarction (AMI).
The disease process of coronary thrombosis: It usually occurs on top of ruptured atheroma, involving platelet aggregation and the coagulation cascade.
Coronary artery spasm: This is a transient, spontaneous coronary vasoconstriction, which may occur in normal coronary arteries or during ongoing coronary thrombosis.
Coronary microvascular dysfunction: This involves damage to the inner walls of the small coronary blood vessels, leading to microvascular spasms, decreased blood flow, and reduced coronary flow reserve.
The disease process of coronary microvascular dysfunction: It can involve structural or functional abnormalities of the microvasculature.
The clinical manifestations of CHD include:
- Angina Pectoris: Stable, Variant, or Microvascular
- Immediate or Sudden Cardiac Death
- Acute Coronary Syndromes (ACS): Unstable Angina, Acute Myocardial Infarction (NSTEMI, STEMI)

CHD - Key Processes

Major factors contributing to CHD can be summarized as follows:
- Atherosclerosis: This is the most prevalent, involving inflammation and plaque buildup in the arteries.
- Coronary thrombosis: This occurs when clots form in the coronary arteries, usually on top of ruptured atheroma.
- Coronary artery spasm: This is a sudden narrowing of the coronary arteries, which impedes blood flow.
- Coronary microvascular dysfunction: This involves problems in the small coronary blood vessels, leading to reduced blood flow.

CHD - Impact on Coronary Function

These processes impact coronary function in several ways:
- Partial coronary occlusion (atherosclerosis): Leads to stable angina.
- Endothelial dysfunction (atherosclerosis): Can trigger coronary artery spasm.
- Ulceration/rupture of plaque (atherosclerosis): Can lead to coronary thrombosis.
- Complete occlusion of coronary artery (coronary thrombosis): Leads to ACS (STEMI).
- Subtotal or intermittent occlusion of coronary artery (coronary thrombosis): Leads to ACS (UA/NSTEMI).
- Thromboembolism in a distal artery (coronary thrombosis): Can cause complications.
- Subtotal or intermittent occlusion of coronary artery (coronary artery spasm): Leads to chest pain.
- Complete focal occlusion of coronary artery (coronary artery spasm): Can lead to ischaemia.
- Reduced coronary flow reserve (coronary microvascular dysfunction): Increases the risk of myocardial ischaemia.
These various consequences highlight the complexity of CHD and the significance of early diagnosis and management.