Chapter 35: Agents Used in Dyslipidemia — Study Notes (Katzung Basic & Clinical Pharmacology, 16th Ed)

CASE STUDY SUMMARY

  • 52-year-old woman with history of lifelong hyperlipidemia symptoms and metabolic syndrome features: BMI 30, abdominal obesity, A1c 6.4% (prediabetes/diabetes risk), ALT ~2× normal, direct LDL 155 mg/dL, triglycerides 458 mg/dL, HDL 40 mg/dL, Lp(a) not elevated, coronary calcium score > 0, no symptoms of coronary disease at baseline.
  • Family history: mother with T2D and overweight; father had MI at 47; both parents on a statin. Patient advised diet/exercise; started on rosuvastatin 20 mg daily and marine omega-3 fatty acids.
  • 3-month follow-up: weight loss 6 lb, LDL 97 mg/dL, TG 340 mg/dL, HDL 45 mg/dL, A1c 5.8%, ALT unchanged. Management question: how to optimize therapy? Consider dual goals of lowering LDL and triglycerides with consideration of hepatic enzyme changes and metabolic syndrome.
  • Final management approach (per case solution): diagnose familial combined hyperlipoproteinemia (FCH) with elevations in both LDL and VLDL remnants contributing to ASCVD risk;abolic syndrome features; target LDL ~ ext{LDL}
    ightarrow ext{about }50 ext{ mg/dL} due to early coronary disease signals (calcium score elevated, family history).
  • Therapeutic steps chosen: add ezetimibe to statin therapy to further reduce LDL; subsequently add fenofibrate to address hypertriglyceridemia and remnant lipoproteins; continue lifestyle measures. Outcome after combined therapy: TG ↓ to 95 mg/dL; LDL ~54 mg/dL; HDL 49 mg/dL; A1c improved to 5.6%; ALT normalized. Plan to pause fibrate if TG stabilize; monitor; consider metformin if A1c rises.
  • Considerations if A1c rises: metformin as needed. Emphasize ongoing diet/exercise/weight reduction. Long-term plan includes maintaining LDL < 100 mg/dL (preferably ~50 mg/dL in high-risk patients) and TG < 150 mg/dL when possible.

OVERVIEW: WHAT IS DYSLIPIDEMIA AND WHY IT MATTERS?

  • Plasma lipids are transported in lipoprotein complexes; disorders of lipoprotein metabolism create hyperlipoproteinemia or hyperlipidemia; hyperlipemia denotes elevated triglycerides.
  • Major clinical consequences: acute pancreatitis (especially with marked hypertriglyceridemia) and atherosclerotic cardiovascular disease (ASCVD).
  • Lipoproteins containing apolipoprotein B-100 deliver lipids into the arterial wall; include LDL, IDL, VLDL, and Lp(a). Chylomicron remnants (apoB-48) also contribute to atherogenesis. HDL has antiatherogenic roles.
  • Atheroma composition: foam cells (transformed macrophages), smooth muscle cells with cholesteryl esters; plaque growth via accumulation of foam cells, collagen, fibrin, calcium. Plaque rupture triggers platelet activation and thrombus formation.
  • Reduction of atherogenic lipoproteins and their oxidation improves endothelial function; benefits appear within 2–3 months of lipid-lowering therapy.

PATHOPHYSIOLOGY AND LIPOPROTEIN METABOLISM (NORMAL)

  • Structure: lipoproteins have a hydrophobic core (cholesteryl esters, triglycerides) surrounded by phospholipids, unesterified cholesterol, and apolipoproteins. Key apo forms:
    • ApoB-48: in chylomicrons and remnants (intestinally derived).
    • ApoB-100: in VLDL, IDL, LDL, Lp(a); liver-derived.
  • HDL species: >20 molecular species with apoA-I; HDL participates in reverse cholesterol transport and antioxidant/anti-inflammatory roles; transfers cholesteryl esters to other lipoproteins via CETP.
  • Key processes:
    • Chylomicrons (A) are formed in the intestine; transport dietary TG and cholesterol; triglycerides are hydrolyzed by LPL; remnants are taken up by liver.
    • VLDL (B) from liver; delivers TG to tissues; after LPL action, VLDL remnants (IDL) form;IDL may be endocytosed or converted to LDL by further triglyceride removal.
    • LDL (C) primarily cleared by receptor-mediated endocytosis; apoB-100 is the ligand for LDL receptor; cholesterol in cells is synthesized de novo via HMG-CoA reductase pathway; majority of LDL is removed by hepatocytes (~70%).
    • Lp(a) (D): LDL-like particle with apo(a); contributes to thrombogenesis inhibition and atherosclerosis; levels are genetically determined and variably elevated.
    • HDL (E): Accepts cholesterol from peripheral tissues via ABCA1 to form prebeta-1 HDL, then via LCAT esterification to mature HDL; CETP mediates transfer of cholesteryl esters to VLDL/LDL remnants; HDL can deliver cholesteryl esters to liver via HDL-SR-BI without endocytosis.
  • Population-level risk: HDL-C inversely correlates with atherosclerosis risk; HDL functionality (cholesterol efflux capacity) varies between individuals.

ATHEROGENESIS AND RISK FACTORS

  • Atherogenesis is multifactorial: inflammation, oxidative stress, endothelial dysfunction, and lipid deposition contribute to plaque formation and instability.
  • Risk factors include cigarette smoking, diabetes, and hypertension; they interact with lipoprotein abnormalities to worsen ASCVD risk.
  • Endothelial nitric oxide (NO) release is diminished by atherogenic lipoproteins, worsening ischemia; reduction in atherogenic lipoproteins and their oxidation improves endothelial function.
  • Modifiable risk management: aggressively target LDL, VLDL/IDL, and HDL functionality; address smoking, diabetes, and hypertension.

DIAGNOSTICS AND TARGET LEVELS

  • Diagnostic approach: fasting lipid panel; differentiate familial from secondary hyperlipoproteinemias via clinical phenotype, genetics, and secondary etiologies (e.g., diabetes, hypothyroidism, nephrosis, cholestasis).
  • Primary goals (general guidance):
    • LDL-C: target often < 100 mg/dL, with high-risk patients aiming for ~50 mg/dL or lower depending on guidelines and comorbidity. In the case study, target ~50 mg/dL due to established ASCVD risk and calcium score elevation.
    • TG: aim < 150 mg/dL; in high-risk hypertriglyceridemia, reduce to sub-phenotypic ranges.
    • HDL-C: higher is generally better, but functional HDL (cholesterol efflux capacity) matters; HDL-C does not directly predict risk in all individuals.
  • Notable numeric references from case:
    • Initial LDL = 155\,\text{mg/dL}; TG = 458\,\text{mg/dL}; HDL = 40\,\text{mg/dL}.
    • Post-treatment LDL = 97\,\text{mg/dL}; TG = 340\,\text{mg/dL}; HDL = 45\,\text{mg/dL}.
    • Case ultimate targets: LDL ~ 50\,\text{mg/dL}; TG < 100–150 mg/dL when possible.

PRIMARY HYPERLIPIDEMIAS: PROFILES AND TREATMENT PRINCIPLES (TABLE 35–1 SUMMARY)

  • Primary chylomicronemia (familial LPL deficiency, Apo C-II deficiency, etc.)
    • Lipoproteins: ↑ Chylomicrons and VLDL; TG often >1000 mg/dL with dietary intake.
    • Management: dietary fat restriction; omega-3 fatty acids; fibrates or niacin; Apo C-III antisense therapy (volanesorsen) is an adjunct; plasmapheresis for acute TG lowering may be used.
  • Familial hypertriglyceridemia
    • Lipoproteins: ↑ VLDL; chylomicrons may be increased or normal.
    • Management: diet; omega-3; fibrates; niacin; statins in cases with elevated LDL; combination therapy often needed.
  • Familial combined hyperlipoproteinemia (FCH)
    • Lipoproteins: ↑ VLDL and/or LDL; Apo B-100 often elevated; pattern may change over time.
    • Management: statin ± ezetimibe ± fibrate ± omega-3; lifestyle modifications; diet; omega-3 may help TG and remnants.
  • Familial dysbetalipoproteinemia
    • Lipoproteins: remnants (VLDL and chylomicron remnants) accumulate; LDL may be normal or reduced; high cholesterol due to remnant buildup; often presents with tuberous xanthomas; associated with hypothyroidism and obesity.
    • Management: statins to upregulate LDL receptors; fibrates may be needed for remnants.
  • Primary hypercholesterolemias (LDL receptor defects; FH)
    • Heterozygous FH: LDL markedly elevated; response to statins and ezetimibe; PCSK9 inhibitors can be beneficial.
    • Homozygous FH: extremely high LDL; combinations required (statins, ezetimibe, lomitapide, PCSK9 inhibitors, ANGPTL3 inhibitors like evinacumab); LDL apheresis may be needed.
    • Lp(a) hyperlipoproteinemia and ApoB-100 variants: Niacin and PCSK9 inhibitors can reduce Lp(a) levels; antisense therapies in development.
  • Lp(a) hyperlipoproteinemia
    • LDL-like particle with apo(a); risk is genetically determined; management includes niacin and PCSK9 MABs; reduction of LDL-C below 100 mg/dL helps mitigate Lp(a)-associated risk.
  • Angiopoietin-like-3 (ANGPTL3) deficiency and therapy
    • ANGPTL3 inhibition (evinacumab) reduces LDL-C in homozygous FH and other hyperlipidemias; mechanism independent of LDL receptor function.
  • Other rare conditions
    • Cholesteryl ester storage disease (LAL deficiency): enzyme replacement therapy sebelipase alfa.
    • Phytosterolemia (ABCG5/ABCG8): eps to reduce phytosterol absorption; ezetimibe effective.
    • HDL deficiencies (Tangier disease, LCAT deficiency): Niacin and other agents modulate LDL/VLDL; aggressive LDL/VLDL reduction remains central.

SECONDARY HYPERLIPOPROTEINEMIA AND DIETARY MODIFIERS

  • Secondary causes (Table 35–2): diabetes mellitus, hypothyroidism, alcohol use, nephrosis (early/severe), cholestasis, estrogens, HIV, myxedema, drugs (protease inhibitors, tacrolimus, sirolimus), etc.
  • Secondary lipoprotein abnormalities can mimic primary disorders; the phenotype often improves with treatment of the underlying condition.
  • Dietary management is foundational and can obviate drug needs or reduce required drug dosages.

DIETARY MANAGEMENT OF HYPERLIPIDEMIA

  • General principles: reduce total fat to 20–25% of calories; saturated fat < 7%; cholesterol < 200 mg/d; limit simple sugars and refined carbohydrates; emphasize complex carbohydrates and fiber; cis-monounsaturated fats preferred.
  • Weight management and caloric balance: weight loss reduces LDL and VLDL; sustained caloric balance is crucial for maintaining lipid improvements.
  • Omega-3 fatty acids (EPA/DHA): reduce triglycerides; EPA-only formulations (icosapent ethyl, Vascepa) also reduce cardiovascular risk beyond triglyceride lowering and can lower apoC-III, an LPL inhibitor.
  • Special dietary needs for severe hypertriglyceridemia or chylomicronemia: very low-fat diet (10–20 g/day; 5 g of essential fatty acids) with fat-soluble vitamin supplementation; manage homocysteine with B vitamins and betaine as indicated; limit red meat to reduce TMAO production.

PHARMACOLOGY OF DRUGS USED IN HYPERLIPIDEMIA

  • Decision framework: choose therapy based on defect and ASCVD/pancreatitis risk; start with diet; use drug combinations for multiple lipid targets; monitor for adverse effects and interactions.
  • General notes on pregnancy and anticoagulants: most lipid-lowering drugs are avoided in pregnancy; adjust anticoagulant dosing when lipids are altered significantly.
  • Pediatric considerations: homozygous FH or severe conditions require early treatment; heterozygous FH may begin in childhood after risk assessment.

STATINS (REDUCTASE INHIBITORS)

  • Examples: Lovastatin, atorvastatin, fluvastatin, pravastatin, simvastatin, rosuvastatin, pitavastatin.
  • Primary effect: ↓ LDL-C; pleiotropic effects include ↓ oxidative stress and vascular inflammation, plaque stabilization; potential antiviral/NAFLD benefits; may retard cancer cell replication in hepatocellular carcinoma.
  • Clinical practice: high-dose statin therapy after acute coronary syndromes is standard irrespective of lipid levels.
  • Chemistry & pharmacokinetics: lactone prodrugs for some (activated in GI tract); pravastatin is active; hepatic first-pass extraction; most excreted in bile; half-lives range ~1–3 h (longer for atorvastatin 14 h, rosuvastatin 19 h, etc.).
  • Mechanism: statins inhibit HMG-CoA reductase, reducing mevalonate and isoprenoid synthesis; this reduces cholesterol synthesis and increases hepatic LDL receptor expression, boosting LDL clearance.
  • Dosing guidelines and potency (typical):
    • Lovastatin: 10–80 mg; Pravastatin: up to 80 mg; Simvastatin: 5–80 mg; Atorvastatin: 10–80 mg; Rosuvastatin: 5–40 mg; Fluvastatin: 20–80 mg; Pitavastatin: 1–4 mg.
  • Adverse effects and monitoring: AST/ALT elevations up to 3× ULN; rare hepatotoxicity; myopathy and potential rhabdomyolysis, especially with drug interactions; CK monitoring if muscle symptoms; risk factors include CYP3A4 inhibitors (e.g., macrolides, cyclosporine, ketoconazole), CYP2C9 interactions (fluvastatin/rosuvastatin with certain inhibitors), grapefruit juice; SLCO1B1 variants increase myopathy risk; CK should be checked if symptoms arise; monitor liver enzymes baseline and periodically; diabetes risk modestly increased; some patients experience cognitive issues (controversial).
  • Dosing considerations: most statins should be given at night due to hepatic cholesterol synthesis timing; atorvastatin and rosuvastatin can be taken any time; pravastatin and rosuvastatin may be preferred with certain drug interactions.
  • Drug interactions and cautions: avoid with strong CYP3A4 inhibitors; fenofibrate preferred with statins to reduce myopathy risk; dose adjustments needed with CK elevations or hepatic dysfunction; avoid red yeast rice products due to variable statin activity and potential nephrotoxin contamination.

FIBRATES (PPAR-α AGONISTS)

  • Examples: Gemfibrozil, fenofibrate; bezafibrate (not available in the USA).
  • Primary effect: ↓ VLDL production and TG; modest effects on LDL; ↑ HDL moderately; upregulate LPL and apolipoproteins A-I/II; enhance fatty acid oxidation.
  • PK/PK: Gemfibrozil: short half-life ~1.5 h; fenofibrate prodrug with 20 h half-life; interactions with anticoagulants; careful in hepatic/renal impairment; avoid in biliary disease due to gallstone risk.
  • Clinical use: particularly helpful in severe hypertriglyceridemia and dysbetalipoproteinemia; can be used with statins but monitor for myopathy; fenofibrate preferred in combination with statin.
  • Toxicity: GI upset, rash, myopathy, hepatotoxicity, gallstones risk; dose adjustments required in liver/renal disease; monitor CK if symptoms of myopathy; fenofibrate better with statin use due to lower myopathy risk.

NIACIN (NICOTINIC ACID)

  • Mechanism: inhibits VLDL secretion, reduces hepatic VLDL production, decreases apoB-containing lipoproteins; increases HDL clearance; reduces Lp(a) in many patients; lowers fibrinogen and may increase tissue plasminogen activator.
  • Dosing: 1.5–3.5 g/day typical; high-dose regimens require slow titration with meals; aspirin 30 minutes prior reduces flushing; sustained-release forms have hepatic toxicity concerns.
  • Benefits/limits: effective at raising HDL substantially; variable effects on CV outcomes; flushing is a common side effect (tachyphylaxis with time); potential hyperuricemia and gout risk; hepatic toxicity risk with long-term high-dose use; glucose tolerance may be impaired; may cause macrocytosis with B12/folate deficiency considerations.
  • Usage notes: often used in combination for mixed dyslipidemia or specific phenotypes; caution in patients with peptic disease or diabetes; monitor liver enzymes and uric acid.

BILE ACID–BINDING RESINS

  • Examples: Colestipol, cholestyramine, colesevelam.
  • Mechanism: large polymeric cationic resins bind bile acids in the intestine, preventing reabsorption; increase hepatic conversion of cholesterol to bile acids; upregulate hepatic LDL receptors; may modestly improve glucose metabolism via incretin pathway activation; some may improve gallstone risk in certain phenotypes.
  • PK/PK: Not absorbed; taken with meals; interactions with absorption of other drugs and fat-soluble vitamins; colesevelam does not bind digoxin, warfarin, or statins to same extent as others.
  • Clinical use: effective for isolated LDL elevations; caution in mixed hyperlipidemia where TG may rise; used as adjunct to statins or ezetimibe.
  • Dosing: 4–5 g/d gradually up to 20 g/d; max 30–32 g/d for some formulations; colesevelam 625 mg tablets or 1875–3750 mg/day suspension; administer separately from other drugs due to absorption issues.
  • Toxicity: constipation, bloating; bowel obstruction risk in diverticulitis; rare malabsorption of fat-soluble vitamins; small risk of steatorrhea; may increase gallstone risk; may impair absorption of various drugs; monitoring of anticoagulants recommended when used with resins.

STEROL ABSORPTION INHIBITOR (EZETIMIBE)

  • Mechanism: selectively inhibits NPC1L1 transporter in intestinal brush border, reducing cholesterol and phytosterol absorption; acts additively with statins to further reduce LDL-C.
  • Pharmacokinetics: rapidly absorbed; glucuronidation to active metabolite; enterohepatic circulation; half-life ~22 h; peak levels ~12–14 h; ~80% excreted in feces.
  • Dosing: 10 mg daily; LDL reduction ~18 ext{–}20 ext{%} as monotherapy; greater reductions when combined with statins (up to ~25% beyond statin alone).
  • Interactions: absorption reduced by cholestyramine and possibly some resins; increases with fibrates; no significant interactions with warfarin/digoxin.
  • Toxicity: generally well tolerated; rare hepatic impairment; rare myositis when combined with statins.

INHIBITION OF MICROSOMAL TRIGLYCERIDE TRANSFER PROTEIN (MTP INHIBITOR)

  • Example: Lomitapide; restricted to homozygous FH; REMS program in place due to safety concerns.
  • Mechanism: reduces assembly/secretion of VLDL in liver and chylomicrons in intestine; lowers LDL by reducing VLDL and apoB-containing lipoproteins.
  • Adverse effects: hepatic fat accumulation, transaminase elevation; requires strict dietary fat restriction and supplementation of fat-soluble vitamins; interacts with 3A4 inhibitors; dose titration with careful monitoring.
  • Dosing: 5–60 mg once daily after evening meal; avoid >30 mg with strong CYP3A4 inhibitors.

PCSK9 INHIBITION (MONOCLONAL ANTIBODIES AND OTHER MODALITIES)

  • PCSK9 antibodies: Evolocumab (Repatha), Alirocumab (Praluent)
    • Mechanism: PCSK9 promotes LDL receptor degradation; antibodies prevent PCSK9 from binding LDLR, increasing receptor recycling and LDL clearance.
    • Dosing: Evolocumab 140 mg every 14 days or 420 mg monthly; Alirocumab 75 or 150 mg every 14 days or 300 mg monthly.
    • Efficacy: LDL reductions up to ~70% in some patients; TG and apoB-100 also reduced; Lp(a) decreases by about 25%.
    • Indications: familial hypercholesterolemia or ASCVD needing additional LDL lowering beyond statins.
    • Toxicity: injection-site reactions, nasopharyngitis, flu-like symptoms; rare myalgia.
  • Inclisiran (siRNA): inclisiran reduces PCSK9 production; LDL-C reductions ~50% with twice-yearly dosing.

BEMPEDOIC ACID AND ANGIOPOIETIN-LIKE-3 INHIBITOR

  • Bempedoic acid: ATP citrate lyase (ACLY) inhibitor; acts in liver to reduce cholesterol synthesis; adds LDL lowering when used with statins; not expected to cause myopathy due to liver-specific activation; potential hyperuricemia and tendon rupture risk.
  • Evainacumab (ANGPTL3 inhibitor): monoclonal antibody targeting ANGPTL3; particularly helpful in homozygous FH when LDL receptor function is absent or reduced; reduces LDL-C by about 49% when added to other therapies; independent of LDL receptor function.

Lp(a) ANTISENSE AND OTHER NOVEL APPROACHES

  • Pelacarsen (antisense oligonucleotide targeting Lp(a)) shows dose-dependent reductions in Lp(a) and oxidized lipids; clinical trials ongoing.
  • Other antisense/siRNA therapies targeting Apo C-III, and other Lp(a)-modulating approaches are in development.
  • CETP inhibitors have not yielded successful clinical results to date.

SUMMARY OF COMBINED THERAPY AND PRACTICAL GUIDANCE

  • When LDL and TG are both elevated, consider combination therapy using agents with complementary mechanisms (e.g., statin + ezetimibe + fibrate or omega-3) while monitoring for interactions and adverse effects.
  • Drugs that interfere with absorption (resins) should be scheduled apart from other lipid-lowering or essential medications to prevent reduced absorption.
  • In high-risk cases (e.g., FH or ASCVD with residual risk), PCSK9 inhibitors or inclisiran may be used in combination with statins or ezetimibe for larger LDL reductions.
  • For severe hypertriglyceridemia and pancreatitis risk, fibrates and omega-3 fatty acids are central; niacin can be considered but flushing and hepatotoxicity limit use.
  • Diet remains foundational; pharmacotherapy should be complemented by weight reduction, physical activity, and management of metabolic syndrome components (glucose, blood pressure, uric acid, etc.).

CASE STUDY ANSWER: KEY TAKEAWAYS

  • Diagnosis: likely familial combined hyperlipidemia (FCH) with elevations in LDL and VLDL remnants; metabolic syndrome features and hepatic steatosis (elevated ALT) consistent with the phenotype.
  • Goal LDL: approximately 50\,\text{mg/dL} given early coronary disease signals and family history.
  • Therapeutic sequence in the case: add ezetimibe to reduce LDL to 58 mg/dL; then add fenofibrate to address hypertriglyceridemia (TG 305 mg/dL reduced to 95 mg/dL); continue lifestyle measures and weight loss; monitor A1c and ALT; plan to pause fibrate if TG stabilizes.
  • Outcomes at 4 months: TG 92 mg/dL; LDL 54 mg/dL; HDL 49 mg/dL; A1c down to 5.6%; ALT normal. Consider metformin if A1c rises again.
  • Long-term plan emphasizes continuing diet/exercise/weight reduction and careful monitoring of lipid parameters; escalate therapy if LDL remains above goal or TG remain elevated.

KEY TERMS AND ACRONYMS

  • Apo B-100: apolipoprotein B-100; ligand for LDL receptors; present on LDL, IDL, VLDL remnants, Lp(a).
  • Apo B-48: apolipoprotein B-48; intestinal origin; present on chylomicrons and chylomicron remnants.
  • Atherogenesis: process of plaque formation in arteries; involves foam cells, inflammatory cells, oxidation of lipids, extracellular matrix deposition.
  • HDL: high-density lipoprotein; antiatherogenic roles include reverse cholesterol transport, antioxidant/anti-inflammatory activities.
  • LDL: low-density lipoprotein; major cholesterol carrier to tissues; elevated levels increase ASCVD risk.
  • Lp(a): lipoprotein(a); LDL-like particle with apo(a); prothrombotic and proatherogenic; level largely genetic.
  • VLDL: very-low-density lipoprotein; carries TG from liver to tissues; TG-rich remnants contribute to atherogenesis.
  • IDL: intermediate-density lipoprotein; remnant of VLDL; can be taken up by liver.
  • ApoC-III: apolipoprotein C-III; inhibits lipolysis of TG-rich lipoproteins; target of volanesorsen.
  • PCSK9: proprotein convertase subtilisin/kexin type 9; promotes LDL receptor degradation; inhibitors increase LDL receptor recycling.
  • CETP: cholesteryl ester transfer protein; facilitates transfer of cholesteryl esters between lipoproteins; CETP inhibitors have not yielded approved agents with clear benefit.
  • MTP: microsomal triglyceride transfer protein; necessary for VLDL and chylomicron assembly; inhibited by lomitapide.
  • ANGPTL3: angiopoietin-like 3; inhibitor (evinacumab) lowers LDL-C and triglycerides independent of LDL receptor function.
  • LAL: lysosomal acid lipase; deficiency causes cholesteryl ester storage disease; sebelipase alfa is enzyme replacement.
  • NPC1L1: Niemann-Pick C1-like 1; transporter targeted by ezetimibe to block cholesterol absorption.
  • ABCA1: transporter involved in HDL formation and cholesterol efflux.
  • SR-BI: scavenger receptor class B type I; mediates selective uptake of cholesteryl esters from HDL to liver.

TABLE REFERENCES (MENTAL MODEL)

  • TABLE 35–1: Primary hyperlipoproteinemias and their treatment strategies (disorders, manifestations, recommended dietary and drug therapy, and combinations).
  • TABLE 35–2: Secondary causes of hyperlipoproteinemia (conditions that can elevate TG, cholesterol, or both).

CONNECTIONS TO FOUNDATIONAL PRINCIPLES

  • LDL receptor pathway and cholesterol homeostasis: drug interventions work primarily by increasing LDL receptor-mediated clearance (statins, ezetimibe, PCSK9 inhibitors, resins).
  • Remnant cholesterol and atherogenesis: VLDL remnants and chylomicron remnants contribute to arterial plaque; managing triglyceride-rich lipoproteins reduces residual ASCVD risk.
  • Reverse cholesterol transport and HDL: HDL’s protective role depends on functional cholesterol efflux and hepatic uptake; therapies that improve HDL quantity but not function may have limited benefit.
  • Metabolic syndrome as risk multiplier: obesity, insulin resistance, and hepatic steatosis worsen dyslipidemia and ASCVD risk; addressing glucose and weight improves lipid outcomes.

FORMULAE AND NUMERICS (LAtex)

  • LDL-C goals for high-risk patients (example from case):
    • ext{LDL-C}
      ightarrow ext{goal} \approx 50\ \text{mg/dL}
  • Case lipid measurements:
    • Initial: \text{LDL} = 155\ \text{mg/dL}, \quad \text{TG} = 458\ \text{mg/dL}, \quad \text{HDL} = 40\ \text{mg/dL}
    • Post-treatment: \text{LDL} = 97\ \text{mg/dL}, \quad \text{TG} = 340\ \text{mg/dL}, \quad \text{HDL} = 45\ \text{mg/dL}
  • Statin pharmacokinetics example: atorvastatin half-life ~14 hours; rosuvastatin ~19 hours; simvastatin ~ short half-life; pravastatin variable; etc.

REFERENCES TO CONCEPTS IN LECTURES

  • The case aligns with teachings on multi-factorial ASCVD risk and the need for aggressive, multi-target lipid-lowering strategies for high-risk patients.
  • Discusses the role of inflammation in atherogenesis and how lipid-lowering therapy reduces acute events beyond plaque regression, consistent with current evidence on pleiotropic statin effects.
  • Highlights emerging therapies (PCSK9 inhibitors, inclisiran, evinacumab, Lp(a) antisense) that target residual risk beyond LDL-C lowering, reflecting ongoing advances in dyslipidemia management.

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