Thrombosis
It reduces platelet aggregation and prevents thrombosis after ACS or stenting, or when aspirin is not tolerated.
Thrombosis
- Mechanism: acute change in vulnerable atherosclerotic plaque
- Common sites: carotid bifurcation, origin of MCA, either end of basilar artery
- Thrombi → progressive narrowing → anterograde extension → may fragment and embolize distally
- Strongly associated with hypertension and diabetes
Read this in Cerebrovascular Disease: Stroke, Ischemia & Hemorrhage Explained
What our notes say
- It reduces platelet aggregation and prevents thrombosis after ACS or stenting, or when aspirin is not tolerated. (Clinical Pharmacology I (MBPL 4400) main exam: 25 January 2023)
- Portal vein thrombosis is a post-hepatic cause of portal hypertension (Internal Medicine 4th Year 1st Semester CAT: HIV and the gut, liver disease and )
- The Wells score is for pulmonary embolism and deep vein thrombosis. (Respiratory Medicine Question Bank: 15 Clinical MCQs)
- Deep Vein Thrombosis and Venous Thromboembolism (with Pulmonary Embolism) — Year 4 Internal Medicine Notes (DVT and Venous Thromboembolism (with Pulmonary Embolism))
- Deep vein thrombosis (DVT): a blood clot in a deep vein, usually of the leg (calf, popliteal, femoral, iliac veins). (DVT and Venous Thromboembolism (with Pulmonary Embolism))
- Counsel on risks of hormone therapy (breast cancer, venous thrombosis, stroke) and review regularly. (Year 4 Gynaecology CAT 1 (MBOG 4212): 2 July 2021)
Study material on Thrombosis
- VASCULAR PATHOLOGY — Must-Know Notes
- VASCULAR PATHOLOGY — Must-Know Comprehensive Notes
- Haemostasis & Coagulation: Platelet Function & Bleeding Disorders
- CNS PATHOLOGY
- Liver Histology & Physiology
- Liver Histology & Physiology
- Hematopathology MCQs & Essays: MBChB Exam Revision Guide
- Medical MCQs: Chemical Pathology & Haematology Exam Review
- Junior Clerkship in Internal Medicine (MBIM4100) main exam, Paper One: 31 January 2024
- CARDIOVASCULAR PATHOLOGY
- Heart Disease — Must Knows
Practice questions on Thrombosis
A 49-year-old man has confirmed anterior LAD thrombosis with elevated troponin. During the next 24 hours, what is the most likely complication?
- Constrictive pericarditis
- Arrhythmia
- Hepatic necrosis
- Thromboembolism
Answer: B. The most common early complication of acute MI within the first 24–48 hours is arrhythmia, due to electrical instability of ischemic myocardium. ---
A patient develops thrombocytopaenia 5–10 days after starting heparin with new thrombosis. The diagnosis is
- ITP
- TTP
- Heparin-induced thrombocytopaenia (HIT)
- DIC
Answer: C. HIT is caused by IgG antibodies against heparin-PF4 complex, activating platelets and causing paradoxical thrombosis despite low platelet count. ---
A 55-year-old woman receives an unfractionated heparin infusion for a deep-vein thrombosis. Which test is most appropriate to monitor her anticoagulant effect?
- Activated partial thromboplastin time (APTT)
- Prothrombin time (PT)
- Thrombin time (TT)
- D-dimer
Answer: A. Unfractionated heparin prolongs the intrinsic pathway, so APTT is the standard monitoring test for dose titration. ---
Which statement correctly distinguishes superficial varicose veins from deep vein thrombosis regarding pulmonary embolism risk?
- Both carry equal PE risk as thrombus can propagate freely between the systems
- DVT is the major source of PE; embolism from superficial varicose veins is very rare
- Varicose veins carry higher embolism risk due to greater peripheral venous pressure
- Neither causes PE without a concurrent cardiac septal defect
Answer: B. Embolism from superficial varicose veins is very rare. DVT — particularly in popliteal, femoral, and iliac veins — is the major source of potentially fatal pulmonary embolism. ---
Which are the most frequent sites of venous thrombosis?
- Veins of lower extremity
- Pelvic veins
- Portal veins
- Hepatic veins
Answer: A. Deep vein thrombosis (DVT) most commonly occurs in the deep veins of the lower extremities. ---
A 33-year-old woman has had multiple episodes of deep venous thrombosis over the past year. Last week she had a transient ischemic attack. On examination there are no abnormal findings. Laboratory studies show a prolonged prothrombin and partial thromboplastin time. When her plasma is mixed in a ratio of 1:1 with normal plasma, neither the PT nor the PTT normalize. Which of the following condition
- Antiphospholipid syndrome
- Hemophilia A
- Von Willebrand disease
- Factor XI deficiency
Answer: A. Antiphospholipid syndrome (APS) is an autoimmune disorder characterized by the presence of antiphospholipid antibodies, which can lead to recurrent arterial and venous thrombosis, and pregnancy morbidity. The prolonged PT and PTT that do not correct upon mixing with normal plasma is a characteristic finding in some patients with APS due to the presence of lupus anticoagulants, which interfere with the clotting assays