🏥 Stations

🧠 Qbank

📖 Book

😃 More

💳 Pricing

🔒 Dashboard

📖 OSCE Learning

🔒 OSCE Stations

🔒 Qbank

🔐 Membership
Share your insights

Help us by sharing what content you've recieved in your exams


Patient on anti-platelet therapy

Specialties > Haematology

Background knowledge 🧠

Definition

  • Anti-platelet therapy involves the use of medications that inhibit platelet aggregation, preventing thrombus formation.
  • Commonly used in the prevention and treatment of cardiovascular diseases, such as myocardial infarction and stroke.
  • Includes drugs like aspirin, clopidogrel, and ticagrelor.

Epidemiology

  • Widely used globally, especially in patients with cardiovascular disease.
  • Increasing use in the ageing population due to rising prevalence of atherosclerotic diseases.
  • Essential in secondary prevention of cardiovascular events in patients with a history of myocardial infarction or stroke.
  • Over 40 million prescriptions annually in the UK.

Aetiology and pathophysiology

  • Atherosclerosis leads to plaque formation, causing endothelial injury and platelet activation.
  • Platelet aggregation contributes to thrombus formation, increasing the risk of occlusive events.
  • Anti-platelet drugs reduce platelet activation and aggregation, lowering the risk of thrombosis.
  • Different drugs target various pathways in platelet activation, e.g., aspirin inhibits COX-1, reducing thromboxane A2 production.

Types

  • Aspirin: Irreversible COX-1 inhibitor.
  • Clopidogrel: P2Y12 receptor antagonist.
  • Ticagrelor: Reversible P2Y12 receptor antagonist.
  • Dipyridamole: Inhibits phosphodiesterase, increasing cAMP in platelets.
  • Prasugrel: Irreversible P2Y12 receptor antagonist, similar to clopidogrel but more potent.

Clinical Features 🌡️

Symptoms

  • Usually asymptomatic unless complications arise.
  • In case of bleeding, symptoms may include bruising, prolonged bleeding from cuts, or gastrointestinal bleeding (melena, hematemesis).
  • Headache or dizziness may occur with certain drugs (e.g., dipyridamole).

Signs

  • Petechiae or purpura in cases of significant bleeding tendency.
  • Signs of anemia (pallor, tachycardia) if significant bleeding has occurred.
  • Evidence of bleeding (e.g., blood in stool, epistaxis) depending on the site of hemorrhage.
  • No specific signs in most patients on stable anti-platelet therapy.

Investigations 🧪

Tests

  • Full blood count (FBC) to assess for anemia or thrombocytopenia.
  • Liver function tests (LFTs) to rule out hepatic causes of bleeding.
  • Renal function tests to assess for renal impairment, which can increase bleeding risk.
  • Coagulation profile (PT, aPTT) typically normal in isolated anti-platelet therapy.
  • Specific platelet function tests (e.g., PFA-100) if indicated.

Management 🥼

Management

  • Primary prevention: Aspirin is sometimes used in selected high-risk individuals (e.g., diabetes, older age), though its role is controversial.
  • Secondary prevention: Aspirin (75 mg daily) with or without clopidogrel for patients with a history of MI or stroke.
  • Duration of dual anti-platelet therapy (DAPT) typically 12 months post-MI, followed by single anti-platelet therapy.
  • Regular monitoring and patient education on signs of bleeding.
  • Consideration of proton pump inhibitors (PPIs) in patients at high risk of gastrointestinal bleeding.

Complications

  • Gastrointestinal bleeding (most common with aspirin).
  • Intracranial hemorrhage (higher risk with dual anti-platelet therapy).
  • Bruising and minor bleeding complications (e.g., epistaxis).
  • Thrombocytopenia (rare but possible with drugs like clopidogrel).
  • Bleeding at surgical sites or invasive procedures.

Prognosis

  • Improved survival rates in patients with cardiovascular disease when used appropriately.
  • Risk of major bleeding needs to be balanced against the benefit of preventing thrombotic events.
  • Long-term use associated with reduced incidence of recurrent MI and ischemic stroke.

Key points

  • Anti-platelet therapy is essential in managing and preventing thrombotic cardiovascular events.
  • Balance between reducing thrombotic risk and minimizing bleeding complications is critical.
  • Aspirin and clopidogrel are the most commonly used agents in the UK.
  • Regular monitoring and patient education are crucial in managing therapy.
  • Emerging therapies and ongoing research continue to evolve management strategies.

No comments yet 😉

Leave a Reply

Haematology