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Question 1. Which lipoprotein is primarily responsible for the transport of dietary triglycerides from the intestine to peripheral tissues? A) VLDL B) LDL C) Chylomicron D) HDL Answer: C Explanation: Chylomicrons are assembled in enterocytes and carry dietary triglycerides and cholesterol through the lymphatic system to the circulation, delivering triglycerides to peripheral tissues. Question 2. The apolipoprotein that serves as the essential cofactor for lipoprotein lipase (LPL) activity is: A) Apo A-I B) Apo B- 100 C) Apo C-II D) Apo E Answer: C Explanation: Apo C-II activates LPL, which hydrolyzes triglycerides in chylomicrons and VLDL, facilitating fatty acid uptake. Question 3. In the endogenous pathway of lipoprotein metabolism, which organ synthesizes VLDL particles? A) Small intestine B) Liver C) Adipose tissue D) Skeletal muscle Answer: B Explanation: The liver assembles VLDL particles containing newly synthesized triglycerides and cholesterol for secretion into the bloodstream.
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Question 4. Which enzyme converts free cholesterol on HDL into cholesteryl ester, thus promoting reverse cholesterol transport? A) LCAT B) CETP C) HMG-CoA reductase D) ACAT Answer: A Explanation: Lecithin-cholesterol acyltransferase (LCAT) esterifies free cholesterol on HDL, allowing HDL to mature and transport cholesterol to the liver. Question 5. The “response-to-injury” hypothesis of atherosclerosis emphasizes the role of which vascular layer? A) Tunica media B) Tunica adventitia C) Endothelium D) Vasa vasorum Answer: C Explanation: Endothelial dysfunction is the initiating event, leading to permeability, leukocyte adhesion, and subsequent plaque formation. Question 6. Foam cells in atherosclerotic plaques are derived primarily from: A) Endothelial cells B) Smooth-muscle cells C) Macrophages that have ingested oxidized LDL D) Platelets Answer: C Explanation: Macrophages take up oxidized LDL via scavenger receptors, become lipid-laden foam cells, and contribute to plaque growth.
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Question 10. According to current ACC/AHA guidelines, when is a non-fasting lipid panel acceptable for routine screening? A) Never; fasting is mandatory B) Only in patients with known diabetes C) In all adults when triglycerides are expected to be <400 mg/dL D) Only for research purposes Answer: C Explanation: Non-fasting panels are acceptable for routine screening because total cholesterol, LDL-C (calculated or direct), and HDL-C are minimally affected; only very high triglycerides require fasting. Question 11. The pooled cohort equations (PCE) for ASCVD risk estimation incorporate which of the following variables? A) Lipoprotein(a) level B) Family history of premature CAD C) Race (White or African-American) D) Carotid intima-media thickness Answer: C Explanation: The PCE includes age, sex, race (White or African-American), total cholesterol, HDL-C, systolic BP, treatment for hypertension, diabetes, and smoking status. Question 12. Which imaging modality provides a quantitative score that directly correlates with coronary atherosclerotic burden? A) Carotid duplex ultrasound B) Coronary artery calcium (CAC) scoring by CT C) Stress echocardiography D) MRI of the aorta Answer: B Explanation: CAC scoring quantifies calcified plaque in coronary arteries and predicts future cardiovascular events.
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Question 13. The Dutch Lipid Clinic Network (DLCN) scoring system is primarily used to diagnose which condition? A) Familial combined hyperlipidemia B) Familial hypercholesterolemia C) Familial chylomicronemia syndrome D) Sitosterolemia Answer: B Explanation: DLCN assigns points for family history, clinical signs, LDL-C levels, and genetic testing to diagnose heterozygous or homozygous FH. Question 14. In familial combined hyperlipidemia (FCHL), which pattern of lipid abnormalities is most typical? A) Isolated elevated LDL-C only B) Isolated elevated triglycerides only C) Variable phenotypes (elevated LDL-C, triglycerides, or both) within the same family D) Low HDL-C with normal LDL-C and TG Answer: C Explanation: FCHL shows heterogeneous lipid profiles that can shift over time, reflecting overproduction of apo B-containing lipoproteins. Question 15. Which genetic defect underlies familial chylomicronemia syndrome (FCS)? A) LDL-R loss-of-function mutation B) Apo E2/E2 genotype C) Lipoprotein lipase (LPL) deficiency D) PCSK9 gain-of-function mutation Answer: C Explanation: FCS results from autosomal recessive loss of LPL activity (or its cofactors), causing severe hypertriglyceridemia and pancreatitis risk.
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Question 19. Which of the following statements about high-intensity statin therapy is correct? A) It reduces LDL-C by ~30 % on average B) It is defined as a ≥50 % reduction in LDL-C C) It is contraindicated in patients >75 years old D) It is only used in secondary prevention Answer: B Explanation: High-intensity statins (e.g., atorvastatin 40– 80 mg, rosuvastatin 20 – 40 mg) achieve ≥ 50 % LDL-C reduction. Question 20. A patient on statin therapy develops muscle pain without CK elevation. The best initial step is: A) Immediate discontinuation of the statin B) Switch to a higher-dose statin C) Perform a trial of a different statin at a lower dose or alternate-day dosing D) Add niacin to reduce symptoms Answer: C Explanation: Statin-associated muscle symptoms (SAMS) are often managed by trying a different statin, lower dose, or alternate-day regimen before stopping therapy. Question 21. Ezetimibe lowers LDL-C by inhibiting: A) HMG-CoA reductase in the liver B) NPC1L1 transporter in the intestinal brush border C) ACAT in the enterocyte D) CETP activity in plasma Answer: B Explanation: Ezetimibe blocks the Niemann-Pick C1-like 1 (NPC1L1) protein, decreasing intestinal absorption of dietary and biliary cholesterol.
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Question 22. PCSK9 inhibitors lower LDL-C by: A) Increasing hepatic bile acid synthesis B) Blocking the degradation of LDL-R, thereby increasing receptor density C) Inhibiting intestinal cholesterol absorption D) Enhancing LPL activity Answer: B Explanation: Monoclonal antibodies (evolocumab, alirocumab) bind PCSK9, preventing it from targeting LDL-R for lysosomal degradation, thus increasing LDL clearance. Question 23. Inclisiran, a small interfering RNA (siRNA) therapy, reduces LDL-C by targeting which hepatic protein? A) HMG-CoA reductase B) PCSK9 mRNA C) Apo B-100 synthesis D) CETP production Answer: B Explanation: Inclisiran silences PCSK9 mRNA, leading to sustained reductions in circulating PCSK9 and LDL-C. Question 24. Bile-acid sequestrants lower LDL-C primarily through: A) Decreasing hepatic cholesterol synthesis B) Increasing fecal excretion of bile acids, prompting up-regulation of LDL-R C) Directly inhibiting HMG-CoA reductase D) Enhancing HDL-C synthesis Answer: B Explanation: By binding bile acids in the gut, sequestrants prevent reabsorption, leading the liver to convert more cholesterol to bile acids and up-regulate LDL-R.
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Question 28. ANGPTL3 inhibition (e.g., evinacumab) primarily reduces which lipid parameters? A) LDL-C only B) Triglycerides and LDL-C C) HDL-C only D) Lp(a) exclusively Answer: B Explanation: ANGPTL3 inhibition increases LPL activity and reduces VLDL production, lowering triglycerides and LDL-C. Question 29. In patients with diabetes mellitus, the preferred first-line lipid-lowering therapy for ASCVD risk reduction is: A) Fibrate B) High-intensity statin C) Niacin D) Bile-acid sequestrant Answer: B Explanation: Statins reduce major cardiovascular events in diabetics and are recommended regardless of baseline LDL-C. Question 30. For children aged 9-11 years, universal lipid screening is recommended because: A) Early detection of FH allows timely lifestyle and pharmacologic interventions B) All children have high triglycerides at this age C) Statins are approved for use in all children over 9 years D) Lipid levels are stable and not influenced by puberty before age 12 Answer: A Explanation: Universal screening can identify heterozygous FH early, allowing diet, exercise, and possibly statin therapy to prevent premature ASCVD.
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Question 31. During pregnancy, which lipid-lowering medication is considered safest if pharmacologic therapy is absolutely required? A) Statins B) Ezetimibe C) Bile-acid sequestrants (e.g., cholestyramine) D) PCSK9 inhibitors Answer: C Explanation: Statins are contraindicated due to teratogenicity; bile-acid sequestrants are not absorbed systemically and are considered relatively safe. Question 32. Post-menopausal women often experience an increase in LDL-C due to: A) Increased hepatic LDL-R expression B) Decreased estrogen-mediated up-regulation of LDL-R C) Increased intestinal cholesterol absorption D) Enhanced LPL activity Answer: B Explanation: Estrogen up-regulates LDL-R; its decline after menopause reduces LDL clearance, raising LDL-C. Question 33. South Asian individuals have a higher ASCVD risk partly because they tend to have: A) Higher HDL-C levels B) Lower triglycerides C) Elevated Lp(a) and small dense LDL particles D) Higher Apo A-I concentrations Answer: C Explanation: South Asians often have higher Lp(a) and a preponderance of atherogenic small dense LDL, contributing to increased risk.
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Question 37. The FOURIER trial evaluated which class of drugs in high-risk patients on statin therapy? A) Bempedoic acid B) PCSK9 inhibitors (evolocumab) C) CETP inhibitors D) Fibrates Answer: B Explanation: Evolocumab significantly reduced LDL-C and cardiovascular events in patients already receiving statins. Question 38. Which lifestyle modification has the greatest impact on raising HDL-C levels? A) Reducing saturated fat intake B) Increasing soluble fiber consumption C) Regular aerobic exercise D) Low-salt diet Answer: C Explanation: Aerobic exercise modestly raises HDL-C; diet changes have less consistent effects. Question 39. Soluble fiber such as psyllium lowers LDL-C primarily by: A) Binding bile acids in the intestine and increasing fecal excretion B) Inhibiting HMG-CoA reductase C) Up-regulating LDL-R transcription directly D) Enhancing intestinal cholesterol absorption Answer: A Explanation: Soluble fiber forms a viscous gel that binds bile acids, prompting hepatic conversion of cholesterol to bile acids, lowering LDL-C. Question 40. Plant sterols/stanols lower LDL-C by:
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A) Inhibiting hepatic cholesterol synthesis B) Competing with dietary cholesterol for incorporation into micelles, reducing absorption C) Up-regulating LDL-R expression D) Increasing LPL activity Answer: B Explanation: Plant sterols/stanols resemble cholesterol and displace it from micelles, decreasing intestinal absorption and LDL-C. Question 41. Which of the following is a recognized risk enhancer that would justify intensifying lipid-lowering therapy in a patient with a 10-year ASCVD risk of 5 %? A) Age 45 B) Family history of premature CAD C) LDL-C 90 mg/dL D) Normal blood pressure Answer: B Explanation: A family history of premature ASCVD is a risk enhancer that can shift treatment thresholds upward. Question 42. In chronic kidney disease (stage 3–4), which lipid abnormality is most common? A) Isolated low HDL-C B) Elevated LDL-C only C) High triglycerides with normal LDL-C D) Low Lp(a) Answer: A Explanation: CKD frequently leads to reduced HDL-C and qualitative HDL dysfunction, contributing to increased cardiovascular risk.
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Question 46. CETP inhibitors (e.g., anacetrapib) primarily increase which lipoprotein fraction? A) LDL-C B) HDL-C C) VLDL-TG D) Lp(a) Answer: B Explanation: CETP inhibition reduces transfer of cholesteryl esters from HDL to VLDL/LDL, raising HDL-C levels. Question 47. Which of the following statements about LDL-C calculation by the Friedewald formula is correct? A) It is accurate when triglycerides >400 mg/dL B) It requires a fasting sample for reliable results C) It directly measures LDL-C by chromatography D) It is unaffected by the presence of chylomicrons Answer: B Explanation: The Friedewald equation assumes fasting triglycerides; high TG levels (>400 mg/dL) make the estimate unreliable. Question 48. In the context of lipidology, “non-HDL-C” is calculated by: A) Total cholesterol minus HDL-C B) LDL-C plus VLDL-C C) Direct measurement of all atherogenic particles D) LDL-C divided by HDL-C Answer: A Explanation: Non-HDL-C = Total cholesterol – HDL-C; it encompasses all atherogenic lipoproteins (VLDL, IDL, LDL, Lp(a)).
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Question 49. Which of the following is a hallmark histologic feature of a vulnerable atherosclerotic plaque? A) Thick fibrous cap with abundant smooth-muscle cells B) Large necrotic core with thin fibrous cap and abundant macrophages C) Predominant calcification without inflammation D) Uniformly dense collagen matrix Answer: B Explanation: Vulnerable plaques have a thin fibrous cap, large lipid-rich necrotic core, and numerous inflammatory cells, predisposing to rupture. Question 50. A 55-year-old woman with rheumatoid arthritis has an LDL-C of 100 mg/dL but an hs-CRP of 5 mg/L. According to ACC/AHA risk enhancers, how should her management be adjusted? A) No change; LDL-C is already optimal B) Intensify statin therapy to achieve LDL-C <70 mg/dL C) Add ezetimibe without changing statin dose D) Initiate fibrate therapy Answer: B Explanation: Chronic inflammatory conditions with elevated hs-CRP are risk enhancers; intensifying statin therapy is recommended. Question 51. Which lipid parameter is most strongly associated with coronary artery calcium progression in asymptomatic adults? A) HDL-C B) Non-HDL-C C) Triglycerides D) Apo A-I Answer: B Explanation: Non-HDL-C captures all atherogenic particles and correlates best with CAC progression.
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Question 55. Which of the following is the most appropriate lipid-lowering strategy for a patient with severe hypertriglyceridemia (TG > 1000 mg/dL) and a history of pancreatitis? A) High-intensity statin alone B) Fibrate plus omega-3 fatty acids C) PCSK9 inhibitor monotherapy D) Niacin monotherapy Answer: B Explanation: Fibrates and high-dose omega-3s effectively lower triglycerides and reduce pancreatitis risk. Question 56. Which of the following best describes the mechanism by which glucocorticoids raise LDL-C? A) Up-regulating hepatic LDL-R expression B) Increasing VLDL production and decreasing LDL-R activity C) Enhancing intestinal cholesterol absorption D) Inhibiting HMG-CoA reductase Answer: B Explanation: Glucocorticoids stimulate hepatic VLDL synthesis and impair LDL-R mediated clearance, raising LDL-C. Question 57. In the context of lipoprotein metabolism, “remnant cholesterol” refers to cholesterol carried in: A) LDL particles only B) HDL particles only C) VLDL, IDL, and chylomicron remnants D) Lp(a) particles exclusively Answer: C Explanation: Remnant cholesterol is the cholesterol content of partially metabolized triglyceride-rich lipoproteins.
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Question 58. Which clinical condition is most commonly associated with elevated Lp(a) levels? A) Familial hypercholesterolemia B) Type 1 diabetes mellitus C) Chronic kidney disease D) Familial combined hyperlipidemia Answer: A Explanation: FH patients often have elevated Lp(a), which adds to their cardiovascular risk independent of LDL-C. Question 59. Which of the following is a major limitation of using LDL-C as the sole therapeutic target in patients with high triglycerides? A) LDL-C underestimates atherogenic particle number when TG are elevated B) LDL-C is unaffected by diet C) LDL-C directly reflects HDL functionality D) LDL-C is not influenced by statin therapy Answer: A Explanation: In hypertriglyceridemia, LDL-C may be low while atherogenic remnant particles are abundant; particle number is a better risk marker. Question 60. The primary benefit of adding a high-dose omega-3 EPA formulation (icosapent ethyl) to statin therapy in high-risk patients is: A) Further LDL-C reduction beyond statins B) Significant reduction in major adverse cardiovascular events (MACE) independent of TG lowering C) Increase in HDL-C to >70 mg/dL D) Decrease in Lp(a) by >50 % Answer: B Explanation: REDUCE-IT demonstrated that EPA reduced MACE even when triglyceride reduction was modest, suggesting pleiotropic benefits.
