Lipid Metabolism & Cardiac Biomarkers in Cardiovascular Disease (Exam-Ready Flashcards)

. What is the primary role of HDL in lipid metabolism?

Reverse cholesterol transport — removes cholesterol from peripheral tissues and returns it to the liver.

What is the function of LDL and its main apolipoprotein?

Function: Transports cholesterol to peripheral tissues
Main apolipoprotein: Apo B100

How are triglycerides transported in the body?

• Exogenous (dietary) fats → Chylomicrons (Apo B48)

• Endogenous fats → VLDL (Apo B100)

What is atherosclerosis?

A chronic inflammatory disease where lipid-rich plaques form in arterial walls, causing narrowing and reduced blood flow (ischaemia).

What is the gold-standard biochemical marker for myocardial infarction (MI)?

Cardiac troponin (cTnI or cTnT)

Why are troponins preferred over CK-MB?

They are highly cardiac-specific and remain elevated for longer (up to ~10 days).

When do troponin levels begin to rise after myocardial injury?

Typically 3–6 hours after onset of chest pain.

What is the significance of high-sensitivity troponin (hs-cTn) assays?

They detect very low troponin levels, allowing earlier rule-in or rule-out of MI.

. What does the “99th percentile” mean in troponin testing?

It is the diagnostic cut-off; values above this indicate myocardial injury.

What are BNP and NT-proBNP used for?

Diagnosis and monitoring of heart failure; released in response to ventricular wall stretch.

What are the key clinical indicators of Acute Coronary Syndrome (ACS)?

Persistent chest pain, ECG changes (e.g. ST elevation), and raised cardiac troponin.

Which older cardiac enzyme is now considered less specific?

Creatine kinase (CK), especially CK-MB

What is the clinical significance of raised LDH in MI?

Rises late (24–48 hours) and remains elevated, but lacks cardiac specificity.

How does hypertension increase cardiovascular risk?

Causes endothelial damage and increased cardiac workload, accelerating atherosclerosis.

What is the Friedewald equation used for?

: Calculating LDL cholesterol:
LDL = Total cholesterol − HDL − (Triglycerides ÷ 2.2)
(Valid only if TG < 4.5 mmol/L)

. Style / exam-type question

Q: A patient presents with chest pain for 2 hours and a normal troponin. What should be done?

Repeat troponin testing after 3–6 hours using a high-sensitivity assay.