Download NWCA Linear Regression Analysis Exam and more Exams Technology in PDF only on Docsity!
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 from the intestinal lumen to the circulation for delivery to adipose and muscle tissue. Question 2. Which apolipoprotein serves as a cofactor for lipoprotein lipase (LPL) activation? A) Apo A‑I B) Apo B‑ 100 C) Apo C‑II D) Apo E Answer: C Explanation: Apo C‑II, found on VLDL and chylomicrons, is essential for activating LPL, which hydrolyzes triglycerides in these particles. Question 3. In the reverse cholesterol transport pathway, which enzyme esterifies free cholesterol on nascent HDL particles? A) LCAT B) CETP C) Hepatic lipase D) ACAT Answer: A
Explanation: Lecithin‑cholesterol acyltransferase (LCAT) transfers a fatty acid from phosphatidylcholine to free cholesterol, forming cholesteryl esters that migrate to the core of HDL. Question 4. Which of the following best describes the “response‑to‑injury” hypothesis of atherosclerosis? A) Lipid accumulation occurs only after plaque rupture. B) Endothelial dysfunction initiates a cascade of inflammatory events. C) Smooth muscle cells proliferate first, then lipids deposit. D) Calcification is the primary initiating event. Answer: B Explanation: The response‑to‑injury hypothesis posits that endothelial injury leads to increased permeability, leukocyte adhesion, and inflammation, setting the stage for plaque formation. Question 5. A patient’s lipid panel shows elevated LDL‑C, normal triglycerides, and low HDL‑C. Which secondary cause should be evaluated first? A) Hypothyroidism B) Nephrotic syndrome C) Excessive alcohol intake D) Chronic glucocorticoid therapy Answer: A Explanation: Primary hypothyroidism commonly raises LDL‑C while having minimal effect on triglycerides; it is a frequent reversible cause of isolated LDL elevation. Question 6. Which laboratory measurement is considered a more accurate marker of atherogenic particle burden in patients with high triglycerides? A) Non‑HDL‑C B) Apo B
Question 9. In patients with very high triglycerides (>1000 mg/dL), which complication is most worrisome? A) Myocardial infarction B) Acute pancreatitis C) Stroke D) Deep‑vein thrombosis Answer: B Explanation: Severe hypertriglyceridemia can cause pancreatic lipase activation within the pancreas, leading to acute pancreatitis, a medical emergency. Question 10. Which of the following lifestyle modifications has the greatest impact on raising HDL‑C levels? A) Reducing saturated fat intake B) Adding soluble fiber to the diet C) Regular aerobic exercise D) Increasing dietary cholesterol Answer: C Explanation: Aerobic exercise stimulates the activity of lipoprotein lipase and enhances reverse cholesterol transport, resulting in modest increases in HDL‑C. Question 11. Which of the following is a characteristic feature of the LDL particle in patients with small, dense LDL phenotype? A) Increased buoyancy on ultracentrifugation B) Higher affinity for LDL receptors C) Greater susceptibility to oxidation D) Lower triglyceride content
Answer: C Explanation: Small, dense LDL particles are more prone to oxidative modification, making them highly atherogenic. Question 12. Which of the following is a primary indication for PCSK9 inhibitor therapy according to current ACC/AHA guidelines? A) Primary prevention in patients with LDL‑C <70 mg/dL B) Secondary prevention in patients with ASCVD and LDL‑C ≥70 mg/dL despite maximally tolerated statin therapy C) Treatment of hypertriglyceridemia >500 mg/dL D) Management of familial combined hyperlipidemia with normal LDL‑C Answer: B Explanation: PCSK9 inhibitors are recommended for patients with established ASCVD who remain above LDL‑C targets despite high‑intensity statin plus ezetimibe. Question 13. Which enzyme transfers cholesteryl esters from HDL to apo B–containing lipoproteins in exchange for triglycerides? A) LCAT B) CETP C) Hepatic lipase D) PLTP Answer: B Explanation: Cholesteryl‑ester transfer protein (CETP) mediates the exchange of cholesteryl esters from HDL to VLDL/LDL and triglycerides in the opposite direction. Question 14. Which of the following is the most appropriate initial lipid‑screening age for a child with a first‑degree relative having premature ASCVD?
Explanation: By binding bile acids in the intestine, sequestrants force the liver to synthesize more bile acids, up‑regulating LDL receptors and lowering LDL‑C. Question 17. Which apolipoprotein is most strongly associated with the formation of foam cells within the arterial intima? A) Apo A‑I B) Apo B‑ 100 C) Apo C‑III D) Apo E Answer: B Explanation: Apo B‑100 is present on LDL particles; when LDL is retained and oxidized in the intima, macrophages ingest it via scavenger receptors, becoming foam cells. Question 18. Which of the following clinical scenarios most likely represents familial combined hyperlipidemia (FCHL)? A) Elevated LDL‑C only in all family members B) Variable lipid phenotypes (high LDL, high TG, or both) among relatives C) Extremely high triglycerides (>2000 mg/dL) with low LDL‑C D) Isolated low HDL‑C with normal LDL‑C and TG Answer: B Explanation: FCHL is characterized by heterogeneous lipid patterns within a family, reflecting overproduction of apo B–containing lipoproteins. Question 19. Which of the following statements about statin‑associated muscle symptoms (SAMS) is correct? A) CK levels are always markedly elevated in SAMS. B) SAMS occur in >20% of patients on high‑intensity statins.
C) Switching to a different statin can often resolve symptoms. D) SAMS are a contraindication to any lipid‑lowering therapy. Answer: C Explanation: Many patients with SAMS tolerate a different statin or a lower dose, indicating a possible no‑cebo effect or variable muscle tolerance. Question 20. Which lipid parameter is most strongly predictive of cardiovascular risk in patients with chronic kidney disease (CKD) stage 3–4? A) Triglycerides B) LDL‑C C) Non‑HDL‑C D) HDL‑C Answer: C Explanation: In CKD, non‑HDL‑C captures the atherogenic burden of LDL, VLDL, and IDL particles, providing better risk prediction than LDL‑C alone. Question 21. Which of the following dietary components is known to lower LDL‑C by inhibiting hepatic cholesterol synthesis? A) Soluble fiber B) Plant sterols/stanols C) Omega‑3 fatty acids D) Trans fats Answer: B Explanation: Plant sterols and stanols compete with cholesterol for incorporation into micelles, reducing absorption and modestly lowering LDL‑C.
Explanation: CAC scoring provides a reproducible, radiation‑based measure of calcified plaque and is strongly correlated with future ASCVD events. Question 25. Which of the following statements about omega‑3 fatty acid therapy is correct? A) EPA‑only formulations have no effect on triglycerides. B) High‑dose EPA/DHA reduce LDL‑C but increase HDL‑C. C) Prescription omega‑3 ethyl esters lower triglycerides and may reduce cardiovascular events. D) Omega‑3s are contraindicated in patients on statins. Answer: C Explanation: Prescription omega‑3 ethyl esters (e.g., icosapent ethyl) significantly lower triglycerides and have shown cardiovascular benefit in REDUCE‑IT. Question 26. Which genetic disorder is characterized by a deficiency of lipoprotein lipase leading to chylomicronemia? A) Familial hypercholesterolemia B) Familial combined hyperlipidemia C) Familial chylomicronemia syndrome (FCS) D) Sitosterolemia Answer: C Explanation: FCS results from autosomal recessive loss‑of‑function mutations in LPL or its cofactors, causing severe hypertriglyceridemia and chylomicron accumulation. Question 27. Which of the following risk enhancers would most likely prompt the use of a higher‑intensity statin in a 45‑year‑old patient with borderline LDL‑C? A) Chronic hepatitis C infection B) Female sex
C) Family history of premature ASCVD D) Low‑dose aspirin use Answer: C Explanation: A first‑degree relative with ASCVD before age 55 (men) or 65 (women) is a strong risk enhancer, supporting more aggressive LDL‑C lowering. Question 28. Which of the following is the primary mechanism by which fibrates lower triglyceride levels? A) Inhibit HMG‑CoA reductase B) Activate PPAR‑α, increasing LPL expression C) Block NPC1L1-mediated cholesterol absorption D) Increase bile acid excretion Answer: B Explanation: Fibrates are PPAR‑α agonists; activation up‑regulates LPL and reduces hepatic VLDL synthesis, leading to lower triglycerides. Question 29. In patients with homozygous familial hypercholesterolemia, which therapeutic option is most effective at dramatically reducing LDL‑C? A) High‑dose niacin B) LDL apheresis C) Low‑dose statin monotherapy D) Fish oil supplementation Answer: B Explanation: LDL apheresis physically removes LDL particles from the circulation and can achieve >50 % LDL‑C reduction in HoFH, where pharmacologic options are limited.
Explanation: Statins and PCSK9 inhibitors are contraindicated in pregnancy; bile‑acid sequestrants may impair fat‑soluble vitamin absorption. Lifestyle modification is preferred. Question 33. In patients with metabolic syndrome, which lipid abnormality is most commonly observed? A) Isolated high LDL‑C B) Low HDL‑C and elevated triglycerides C) Elevated Lp(a) D) High total cholesterol with normal fractions Answer: B Explanation: Metabolic syndrome is typified by atherogenic dyslipidemia: low HDL‑C, high triglycerides, and small dense LDL particles. Question 34. Which of the following best explains why the Friedewald equation may be inaccurate when triglycerides exceed 400 mg/dL? A) It assumes a fixed ratio of VLDL‑C to triglycerides. B) It overestimates LDL‑C due to cholesterol esterification. C) It does not account for HDL subfractions. D) It uses LDL‑C to calculate triglycerides. Answer: A Explanation: The Friedewald formula estimates VLDL‑C as triglycerides/5; this ratio becomes unreliable when triglyceride levels are markedly elevated. Question 35. Which of the following mechanisms underlies the LDL‑C lowering effect of bempedoic acid? A) Direct inhibition of HMG‑CoA reductase in the liver B) Activation of LDL‑R transcription via SREBP‑ 2
C) Inhibition of ATP‑citrate lyase upstream of HMG‑CoA reductase D) Blocking intestinal cholesterol absorption Answer: C Explanation: Bempedoic acid inhibits ATP‑citrate lyase, reducing hepatic cholesterol synthesis and up‑regulating LDL receptors, thereby lowering LDL‑C. Question 36. Which of the following clinical findings would most strongly suggest a secondary cause of hypertriglyceridemia? A) Serum triglycerides of 250 mg/dL without other abnormalities B) Triglycerides >1000 mg/dL after a binge of alcohol C) Persistent triglycerides >500 mg/dL despite diet and weight loss D) Triglycerides of 150 mg/dL with normal LDL‑C Answer: B Explanation: Acute excessive alcohol intake can dramatically raise triglycerides; identifying this trigger points to a secondary cause. Question 37. Which of the following statements regarding lipoprotein(a) [Lp(a)] is correct? A) Lp(a) levels are significantly reduced by statins. B) Lp(a) is composed of an LDL particle attached to apolipoprotein(a). C) Lifestyle modifications markedly lower Lp(a). D) Lp(a) measurement is unnecessary in ASCVD risk assessment. Answer: B Explanation: Lp(a) consists of an LDL‑like particle covalently bound to apolipoprotein(a); its concentration is largely genetically determined and not markedly altered by most therapies. Question 38. Which of the following best describes the effect of PCSK9 on LDL receptors?
Explanation: ACE inhibitors can modestly raise HDL‑C, whereas non‑vasodilating beta‑blockers and thiazides may lower HDL‑C. Question 41. Which of the following is the most appropriate next step for a patient on high‑intensity statin therapy who develops CK levels 5‑times the upper limit of normal but no symptoms? A) Continue statin and monitor CK weekly B) Discontinue statin immediately C) Reduce statin dose and re‑check CK in 2 weeks D) Switch to a fibrate Answer: B Explanation: CK elevations >10× ULN or ≥5× ULN with pain warrant statin discontinuation; asymptomatic CK 5× ULN still requires stopping the drug and evaluating. Question 42. Which of the following best explains why women generally have higher HDL‑C levels than men? A) Higher hepatic lipase activity in women B) Estrogen‑mediated up‑regulation of apo A‑I synthesis C) Greater intake of saturated fat D) Lower physical activity levels Answer: B Explanation: Estrogen enhances hepatic production of apo A‑I and decreases hepatic lipase activity, contributing to higher HDL‑C in premenopausal women. Question 43. Which of the following statements regarding the relationship between LDL particle size and cardiovascular risk is accurate? A) Large, buoyant LDL particles are more atherogenic.
B) Small, dense LDL particles are associated with higher risk. C) LDL particle size does not affect risk. D) Only LDL‑C concentration matters, not size. Answer: B Explanation: Small, dense LDL particles penetrate the arterial wall more readily and are more prone to oxidation, conferring greater atherogenic potential. Question 44. Which of the following is a primary benefit of using PCSK9 siRNA (inclisiran) over monoclonal antibodies? A) Oral administration B) Once‑yearly dosing C) No need for LDL‑C monitoring D) Lower cost Answer: B Explanation: Inclisiran utilizes RNA interference and is administered subcutaneously twice yearly after the initial loading doses, offering a convenient dosing schedule. Question 45. Which of the following is the most common cause of secondary hypercholesterolemia in patients receiving chronic glucocorticoid therapy? A) Increased LDL receptor degradation B) Up‑regulation of HMG‑CoA reductase C) Enhanced intestinal cholesterol absorption D) Decreased bile acid synthesis Answer: B Explanation: Glucocorticoids stimulate hepatic HMG‑CoA reductase activity, raising endogenous cholesterol synthesis and LDL‑C levels.
Answer: D Explanation: Remnant cholesterol includes cholesterol carried in triglyceride‑rich particles such as VLDL and chylomicron remnants, which are highly atherogenic. Question 49. Which of the following statements about the effect of niacin on cardiovascular outcomes is correct?** A) Niacin significantly reduces ASCVD events when added to statin therapy. B) Niacin raises HDL‑C but does not improve outcomes and may increase adverse events. C) Niacin is the first‑line therapy for hypertriglyceridemia. D) Niacin markedly lowers Lp(a) levels. Answer: B Explanation: While niacin increases HDL‑C, large trials (e.g., AIM‑HIGH, HPS2‑THRIVE) showed no cardiovascular benefit and higher rates of flushing and hepatotoxicity. Question 50. Which of the following is the most appropriate management for a patient with severe hypertriglyceridemia (TG > 1000 mg/dL) who is also on a high‑dose omega‑3 prescription?** A) Add a fibrate B) Increase the omega‑3 dose further C) Initiate insulin infusion D) Discontinue statin therapy Answer: A Explanation: Adding a fibrate (gemfibrozil or fenofibrate) synergistically lowers triglycerides and reduces pancreatitis risk in severe hypertriglyceridemia. Question 51. Which of the following best explains why LDL‑C targets are lower for patients with diabetes?** A) Diabetics have higher HDL‑C, requiring lower LDL‑C to balance risk.
B) Diabetes accelerates atherosclerosis, warranting more aggressive LDL‑C reduction. C) Statins are less effective in diabetics, so lower targets compensate. D) LDL‑C measurement is less accurate in diabetics. Answer: B Explanation: Hyperglycemia promotes endothelial dysfunction and inflammation, increasing ASCVD risk; therefore, guideline‑recommended LDL‑C targets are more stringent. Question 52. Which of the following is the primary pharmacologic effect of bile‑acid sequestrants on LDL‑C?** A) Inhibition of intestinal cholesterol absorption B) Up‑regulation of hepatic LDL receptors via decreased intracellular cholesterol C) Direct inhibition of HMG‑CoA reductase D) Activation of PPAR‑α Answer: B Explanation: By binding bile acids, sequestrants force the liver to convert more cholesterol into bile acids, depleting intracellular cholesterol and up‑regulating LDL receptors, thus lowering LDL‑C. Question 53. Which of the following best characterizes the lipid profile typically seen in patients with nephrotic syndrome?** A) Low LDL‑C, high HDL‑C, normal TG B) Elevated LDL‑C, low HDL‑C, elevated TG C) Isolated high Lp(a) D) Normal lipid panel Answer: B Explanation: Nephrotic syndrome leads to hepatic up‑regulation of lipoprotein synthesis, causing high LDL‑C, high TG, and reduced HDL‑C.
