Is oral anticoagulation (OAC) indicated for a patient with a history of multiple cerebrovascular accidents (CVAs) and a pacemaker, without left atrial appendage thrombus?

Oral Anticoagulation for a Patient with Multiple CVAs, Pacemaker, and No Left Atrial Appendage Thrombus

Oral anticoagulation is strongly indicated for this 60-year-old African-American female with a history of multiple CVAs and a pacemaker, even in the absence of left atrial appendage thrombus. 1, 2

Indications for Anticoagulation

• In patients with ischemic stroke or TIA with nonvalvular atrial fibrillation or flutter (whether paroxysmal, persistent, or permanent), oral anticoagulation is recommended 1
• The presence of a pacemaker increases the risk of atrial high-rate episodes (AHREs), which are associated with an increased risk of thromboembolism 1
• A history of multiple CVAs significantly increases this patient's CHA₂DS₂-VASc score, placing her at high risk for recurrent stroke 1
• The absence of left atrial appendage thrombus does not negate the need for anticoagulation, as thrombi can form rapidly in high-risk patients 2

Anticoagulation Options

• Direct oral anticoagulants (DOACs) are preferred over vitamin K antagonists for nonvalvular atrial fibrillation due to:

  • Superior efficacy in preventing thromboembolism 1, 2
  • Lower risk of intracranial hemorrhage compared to warfarin 2
  • More consistent anticoagulation without need for frequent monitoring 1

• If DOACs are contraindicated, vitamin K antagonists (warfarin) with a target INR of 2.0-3.0 should be used 2

Risk Assessment

• The patient's CHA₂DS₂-VASc score includes:

  • Age (60 years): +1 point
  • Female sex: +1 point
  • History of stroke/TIA: +2 points
  • Total score: 4 points (high risk) 1

• With a CHA₂DS₂-VASc score of 4, the annual stroke risk is significantly elevated, strongly warranting anticoagulation 1

Special Considerations

• For patients with pacemakers, continuation of anticoagulation during device implantation has shown a trend toward reduced complications compared to interruption 3
• The presence of a pacemaker may be associated with subclinical atrial fibrillation or atrial high-rate episodes (AHREs), which increase stroke risk 1
• Even in the absence of documented atrial fibrillation, the history of multiple CVAs suggests a high risk of recurrent events that would benefit from anticoagulation 1

Monitoring and Follow-up

• Regular reassessment of thromboembolic and bleeding risks is recommended 2
• If using warfarin, aim for time in therapeutic range (TTR) >70%; consider switching to a DOAC if this cannot be achieved 2
• Echocardiographic surveillance may be warranted to monitor for development of left atrial appendage thrombus 4

Potential Pitfalls

• Antiplatelet therapy alone is not an adequate substitute for oral anticoagulation in this high-risk patient 2
• Left atrial appendage occlusion devices should only be considered if the patient has absolute contraindications to long-term anticoagulation 2, 5
• Device-related thrombus is a potential complication of left atrial appendage closure devices, which can lead to embolic events 5, 6, 4
• Interruption of anticoagulation for procedures increases thromboembolic risk and should be minimized 3