A 55-year-old man has been told by his doctor that he has cardiovascular disease and will need treatment. The doctor explains two possible treatments: statins and coronary bypass surgery. Evaluate the use of these two treatments for cardiovascular disease.

Edexcel A-Level Biology A: Salters-Nuffield (9BN0) — 1.1 Cardiovascular disease and risk · Evaluate · 5 marks · View as Markdown

Written & reviewed by James Millett — Biology (Imperial College London), PGCE Science (University of Cambridge).

Statins are drugs that lower blood cholesterol levels. Coronary bypass surgery uses a section of healthy blood vessel, taken from elsewhere in the body, to create a new route for blood to flow around a blocked coronary artery.

Model answer (5 marks)

Statins lower LDL‑cholesterol, reducing atheroma formation in coronary arteries.
Statins are taken long‑term, are not a cure, and can cause side effects such as myalgia and liver enzyme changes.
Coronary bypass surgery creates a new route for blood, restoring flow around a blocked artery.
Bypass is invasive, carries operative risks (bleeding, infection, arrhythmia) and requires a recovery period.
Overall, statins are preferable as a first‑line, preventive, low‑risk treatment; bypass is reserved for severe, symptomatic blockages where medication is insufficient.

Examiner tips

  • Use the command word ‘evaluate’ – list benefits and drawbacks of each treatment, then give a reasoned comparison.
  • Show clear comparison: first‑line vs. definitive intervention.
  • Use specific terms: LDL‑cholesterol, atheroma, invasive, long‑term medication.
  • Keep answer concise – 5 marks, so one sentence per point is enough.

Common mistakes

  • Treating statins as a cure rather than a preventive measure.
  • Omitting the side‑effect or risk aspects of each treatment.
  • Failing to compare the two treatments in a concluding sentence.

Mark scheme (5 marks)

  1. Statins reduce blood cholesterol levels, which reduces the build-up of fatty deposits (atheroma) in coronary arteries
  2. Statins have side effects / must be taken long-term / are a long-term medication not a cure
  3. Coronary bypass surgery directly restores blood flow to the heart muscle by bypassing the blocked artery
  4. Coronary bypass surgery carries significant risks as it is an invasive/major surgical procedure
  5. Reasoned conclusion comparing the two treatments, e.g. statins are preferable as a first/preventative option whereas bypass surgery is necessary when blockage is severe / both have advantages and limitations

Key terms in this question

cardiovascular disease · statins · coronary bypass surgery

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