75 years old male presents to emergency department with LRTI for last few days, has been on oral antibiotics from GP. He is on warfarin for his mechanical prosthetic heart valve and his INR comes back at 6. Last INR check was about 4 weeks ago and it was normal. He has been taking warfarin regularly.

Answers: 

1. Most important considerations while managing a patient with supratherapeutic INR are :

  What is the indication of warfarin? 

• There are potentional downsides to excessive correction of the INR — patients with mechanical heart valves are at high risk of thromboembolic complications so reversal with large doses of vitamin K  means the patient may require prolonged heparinisation until he becomes warfarin sensitive again. If vitamin K is given in this case, small doses should be administered and titrated according to serial INR.

• Is there evidence of active bleeding ? , and how high is the INR? 

Above 2 features help us to determine SEVERITY of anticoagulation, and how  much anti reversal agent is needed, and the urgency with which reversal needs to be given.

Other factors important in elderly patients include:

• elderly patients are less tolerant of significant hemorrhage:
  • they have less “physiological reserve”.
  • they are more likely to have other comorbidities that impair compensatory mechanisms.
• elderly patients are more likely to have significant hemorrhage because:
  • they may be more prone to falls and other injury mechanisms, e.g. higher risk of intracranial hemorrhage should they sustain a head injury.
  • comorbidities (e.g. peptic ulcer disease) and other medications (e.g. clopidogrel, aspirin) are more likely to be present.

Answer 2:  Bleeding risk increases exponentially with INR readings above 5. However INR of 8 with no evidence of active bleeding and otherwise stable should be managed as below.

Bleeding Absent ( Low risk ) >      stop warfarin, measure INR in 24 hours, resume at low dose when it is in therapeutic range.

Bleeding Absent ( High Risk) >    1-2 mg oral OR 0.5-1 mg IV vit k, measure INR in 24 hours, resume at low dose when it is in therapeutic range.

Answer 3. Now when patient has ICH ( high risk of expanding ), INR needs to be revered urgently , even though patient has mechanical valve. Patients clinical status, scans , should be discussed with neurosurgeons and exact management could vary from patient to patient but usually patient like above will need following :

Prothrombinex 25-50 IU per Kg

Vit K IV 5-10 mg IV.

FFP is also considered on top of Prothrombinex for high risk bleeding or massive hemorrhage.

Once INR is reversed , close observation for any neurology, repeat scan in 24-48 hours , and then heparanization can be started in consultation with neurosurgery, cardio thoracic/  hematology.

High Bleeding Risk one or more : Recent surgery, trauma, bleed, renal failure, Alcohol abuse, anti platelet therapy, Advanced age, Hypertension, Active GI bleed.