Venous Thromboembolism — SAQ

Stem

A 67-year-old man is day 5 after hip arthroplasty. He develops pleuritic pain, heart rate 112/min, saturations 92 percent on air, and a swollen tender right calf. Blood pressure is 128/78 mmHg. Outline diagnosis and treatment using named trials and guideline doses.^[1]

Core knowledge

VTE is DVT plus PE. ESC 2019: third most frequent acute cardiovascular syndrome after MI and stroke; PE incidence 39–115 per 100 000, DVT 53–162 per 100 000. ASH 2020: about 1 to 2 per 1000 per year. This patient is normotensive, so he is not high-risk PE.^[1][2]

Red flags

• Systolic BP under 90 mmHg, shock, or arrest — high-risk PE; systemic thrombolysis (ESC rtPA 100 mg over 2 h); do not queue for CT.^[1][2]
• Intermediate-risk (RV strain plus troponin, still normotensive) — PEITHO used tenecteplase, not alteplase, and increased major bleeding and stroke; do not lyse routinely.^[5]
• Pregnancy — ASH strong recommendation for LMWH over UFH; VTE about 1.2 per 1000 deliveries.^[3]

Key doses / thresholds

• Apixaban 10 mg twice daily for 7 days then 5 mg twice daily (AMPLIFY).^[4]
• Rivaroxaban 15 mg twice daily for 3 weeks then 20 mg daily (EINSTEIN).
• rtPA 100 mg over 2 hours (ESC); accelerated 0.6 mg/kg over 15 min, maximum 50 mg.^[1]
• Christopher: PE-unlikely plus normal D-dimer — subsequent nonfatal VTE 0.5 percent.^[6]

Questions

a) Define VTE and the ESC haemodynamic-instability rule that marks high-risk PE. (3 marks)

b) How would you diagnose suspected PE in this stable patient? Name the Christopher result. (4 marks)

c) Give a first-line anticoagulant regimen with trial name and loading dose. When would you lyse instead? (5 marks)

d) What did PEITHO show, and how does that change intermediate-risk management? (3 marks)

Model outline

a) VTE = DVT + PE. High-risk = cardiac arrest, obstructive shock (systolic BP under 90 mmHg or vasopressors to reach 90 plus hypoperfusion), or persistent hypotension (under 90 or a 40 mmHg drop for over 15 min not due to arrhythmia, hypovolaemia or sepsis).^[1]

b) Wells/clinical probability, then D-dimer if unlikely, then CTPA. Christopher: PE-unlikely + normal D-dimer in 32.0 percent; untreated subsequent nonfatal VTE 0.5 percent.^[6]

c) Apixaban 10 mg twice daily for 7 days then 5 mg twice daily (AMPLIFY, 2.3 vs 2.7 percent recurrence, major bleed 0.6 vs 1.8 percent). Lyse only if he becomes haemodynamically compromised (ASH strong; ESC rtPA 100 mg/2 h).^[4][2][1]

d) Tenecteplase vs placebo in intermediate-risk PE: death or decompensation 2.6 vs 5.6 percent; extracranial bleeding 6.3 vs 1.2 percent; stroke 2.4 percent. Anticoagulate and watch; rescue if unstable.^[5]

References6ShowHide

1. [1]Konstantinides SV, Meyer G, Becattini C, et al. 2019 ESC Guidelines for the diagnosis and management of acute pulmonary embolism developed in collaboration with the European Respiratory Society (ERS) Eur Heart J, 2020.PMID 31504429
2. [2]Ortel TL, Neumann I, Ageno W, et al. American Society of Hematology 2020 guidelines for management of venous thromboembolism: treatment of deep vein thrombosis and pulmonary embolism Blood Adv, 2020.PMID 33007077
3. [3]Bates SM, Rajasekhar A, Middeldorp S, et al. American Society of Hematology 2018 guidelines for management of venous thromboembolism: venous thromboembolism in the context of pregnancy Blood Adv, 2018.PMID 30482767
4. [4]Agnelli G, Buller HR, Cohen A, et al. Oral apixaban for the treatment of acute venous thromboembolism N Engl J Med, 2013.PMID 23808982
5. [5]Meyer G, Vicaut E, Danays T, et al. Fibrinolysis for patients with intermediate-risk pulmonary embolism N Engl J Med, 2014.PMID 24716681
6. [6]van Belle A, Büller HR, Huisman MV, et al. Effectiveness of managing suspected pulmonary embolism using an algorithm combining clinical probability, D-dimer testing, and computed tomography JAMA, 2006.PMID 16403929