Blood & Clots Series: ThromboPhonia E01, Mechanical Valves and Intracranial Hemorrhage

In Blood & Clots, Medical Concepts by Sameer SharifLeave a Comment

Blood & Clots Podcast, Thrombophonia: Episode 1

A 65-year-old man presents to the Emergency Department after suffering from an intracerebral hemorrhage (ICH). He has a past medical history of hypertension, dyslipidemia, a mechanical aortic valve replacement, diabetes, and sleep apnea. His medications include ramipril, atorvastatin, aspirin, metformin, and warfarin.

How should this patient be managed? What should be done with his anticoagulation? Listen to the podcast below and read the blog post below!

Objectives

After listening to this podcast, learners should be able to:

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1. Summarize an approach to the acute management of patients with intracerebral hemorrhage while on anticoagulation for a mechanical heart valve

ABCs

  • Airway: prioritize airway management if low GCS
  • Breathing
  • Circulation: obtain IV access, address hemorrhage, optimize hemodynamics to prevent secondary brain injury

Reversal of Warfarin Anticoagulation

  • Stop all anticoagulant/antiplatelet agents
  • Vitamin K 5-10mg IV 1, 2
  • Prothrombin complex concentrate – dose calculated according to weight and INR 2
  • Goal of INR < 1.41
  • Daily INR checks and further correction with Vitamin K to maintain INR below 1.4.1

Does thrombosis risk vary with mechanical valve type (aortic vs mitral), and why?

  • Left sided valves (aortic, mitral) both carry risk of systemic embolization
  • Mitral valves higher risk than aortic valve due to lower flow on atrial side of mitral valve
  • Annual risk of valve thrombosis and systemic embolization 12-15% for mitral valves, 5-8% for aortic valves
  • If dual mechanical valves, additive risk per valve and therefore overall higher risk
  • Type of valve: newer bileaflet design valves carry lower thrombotic risk than older designs (tilting-disk or ball & cage design 3
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2. Describe the benefits and risks of anticoagulant reversal, including the risk of thromboembolism

What is the short-term risk of thrombosis after warfarin reversal?

  • Thrombosis risk after PCC administration is 1-2% in the short-term — more related to the underlying disease than pro-thrombotic properties of PCC itself

How do you weigh the risk of the patient re-bleeding versus their valve clotting in the short-term?

  • Risk of progression of ICH in all patients: 30%4
  • Risk of mortality in ICH: all patients (with or without anticoagulants) – 26%, on warfarin – 52% 5
  • Risk of thromboembolism with mechanical valve and no anticoagulation: 8.6 events per 100 patient years 6
  • As risk of progression/rebleeding is much higher than risk of thrombosis, consensus is to immediately reverse anticoagulation in these patients

At what time points after valve replacement surgery are patients at higher risk of thrombosis?

  • 24% of thrombotic events occur within the first year following valve replacement6
  • First 1-3 months are highest risk: sewing of ring into tissue creates thrombogenic surface which increases risk immediately post-operatively and then decreases after becoming epithelialized 3 months post-op 3
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3. Describe the principles of effective communication and collaboration of bleeding & clotting cases with consultants

Which consultants should I call and when?

Thrombosis

  • Consult early to advise about reversal of anticoagulation in ICH

Neurosurgery

  • Consultation for patients with ICH and communicate imaging findings
  • Very few indications for surgery in spontaneous ICH and therefore less crucial to consult early; however STICH-II Trial showed that a subpopulation of very neurologically sick patients may benefit from early surgery7, 8

What pertinent information should be communicated?

Demographics

  • Code status
  • History
  • Past medical history
  • Medications: other antithrombotics, antiplatelets
  • Indication for anticoagulation/antiplatelet agent
  • INR: level, and if therapeutic vs. supratherapeutic
  • Risk factors for thrombosis: mechanical valve, history of VTE, atrial fibrillation
  • Physical examination including level of consciousness and neurologic deficits
  • Imaging findings:
    • Type of bleeding: epidural hematoma, subdural hematoma, subarachnoid hemorrhage, intraparenchymal hemorrhage
    • Type of intraparenchymal hemorrhage: lobar, cortical or deep
    • Location of intracranial hemorrhage

How to collaborate/navigate and prioritize between different consultants?

  • Prioritize immediate reversal of anticoagulation
  • Early consultation with neurosurgery if patient has ICH that is potentially amenable to surgery
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The notes for this podcast was created by Alisha Greer (PGY2 Emergency Medicine at McMaster University) and uploaded by Rebecca Dang.

References

1.
Frontera J, Lewin J, Rabinstein A, et al. Guideline for Reversal of Antithrombotics in Intracranial Hemorrhage: A Statement for Healthcare Professionals from the Neurocritical Care Society and Society of Critical Care Medicine. Neurocrit Care. 2016;24(1):6-46. [PubMed]
2.
Panduranga P, Al-Mukhaini M, Al-Muslahi M, Haque M, Shehab A. Management dilemmas in patients with mechanical heart valves and warfarin-induced major bleeding. World J Cardiol. 2012;4(3):54-59. [PubMed]
3.
Dangas G, Weitz J, Giustino G, Makkar R, Mehran R. Prosthetic Heart Valve Thrombosis. J Am Coll Cardiol. 2016;68(24):2670-2689. [PubMed]
4.
Brouwers H, Greenberg S. Hematoma expansion following acute intracerebral hemorrhage. Cerebrovasc Dis. 2013;35(3):195-201. [PubMed]
5.
Rosand J, Eckman M, Knudsen K, Singer D, Greenberg S. The effect of warfarin and intensity of anticoagulation on outcome of intracerebral hemorrhage. Arch Intern Med. 2004;164(8):880-884. [PubMed]
6.
Cannegieter S, Rosendaal F, Briët E. Thromboembolic and bleeding complications in patients with mechanical heart valve prostheses. Circulation. 1994;89(2):635-641. [PubMed]
7.
Roudaut R, Serri K, Lafitte S. Thrombosis of prosthetic heart valves: diagnosis and therapeutic considerations. Heart. 2007;93(1):137-142. [PubMed]
8.
Mendelow A, Gregson B, Rowan E, et al. Early surgery versus initial conservative treatment in patients with spontaneous supratentorial lobar intracerebral haematomas (STICH II): a randomised trial. Lancet. 2013;382(9890):397-408. [PubMed]
Sameer Sharif

Sameer Sharif

Dr. Sameer Sharif is an Emergency Physician at the Hamilton Health Sciences and is completing his Critical Care Fellowship at McMaster University.