Cardiovascular Drugs USMLE Step 1 Practice Question
A 70-year-old woman with a history of myocardial infarction 2 years ago presents for follow-up. She has been adherent to atorvastatin 80 mg daily for the past 18 months. Current vital signs: BP 136/80 mmHg, HR 68 bpm. Recent lipid panel shows LDL cholesterol 102 mg/dL, HDL cholesterol 38 mg/dL, and triglycerides 180 mg/dL. Liver function tests and creatine kinase are normal. Her cardiologist is considering the addition of a PCSK9 inhibitor to reduce her residual cardiovascular risk. Which of the following best describes the mechanism by which PCSK9 inhibitors reduce plasma LDL cholesterol concentration?
Answer choices
- AInhibition of HMG-CoA reductase in hepatic mitochondria
- BDecreased hepatic synthesis of apolipoprotein B-100
- CInhibition of PCSK9-mediated degradation of LDL receptors, increasing their surface expression on hepatocytesCorrect answer
- DIncreased activity of lipoprotein lipase in adipose tissue
- EReduced intestinal absorption of dietary cholesterol via inhibition of NPC1L1
- FEnhanced conversion of hepatic cholesterol to bile acids
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