Antithrombotic Therapy for Cerebrovascular Disorders: Immediate Anticoagulation of Embolic Stroke

Immediate Anticoagulation of Embolic Stroke
The proper time to initiate anticoagulation following aseptic cardiogenic brain embolism is controversial. Early, recurrent embolism to the brain or other organs can follow initial embolism from all cardiac sources, and immediate anticoagulation intuitively appears indicated. Level V studies suggest that about 12% (range, 0-22%) of patients with cardiogenic brain embolism will experience a second embolic stroke within 2 weeks. The early recurrence risk is spread fairly evenly over the initial 14 days (about 1% daily for the first 10 days), with no “grace period” in the first days following initial embolism. Level III and IV studies have reported a reduction of early recurrent embolism in anticoagulated patients to about one third that of nonanticoagulated patients. The single level II randomized trial involved only 45 patients and demonstrated a lower recurrence in anticoagulated patients. The risk of symptomatic brain hemorrhage associated with the immediate anticoagulation of aseptic embolic stroke patients is difficult to define. Several studies have reported no hemorrhagic worsening in immediately anticoagulated patients. Others have reported hemorrhagic worsening in 1.4-24% of immediately anticoagulated patients. Patients who are receiving anticoagulation at the time of initial embolism may be at special risk of hemorrhagic worsening. more
Large infarctions appear to be overrepresented in patients who experience hemorrhagic worsening associated with immediate anticoagulation of aseptic embolic strokes, perhaps constituting an identifiable risk factor for this complication.® Spontaneous hemorrhagic transformation of initially pale embolic infarctions in nonanticoagulated patients can be delayed for several days following stroke, although most occur within 48 h. Postponing anticoagulation until CT documents absence of spontaneous hemorrhagic transformation seems prudent. While iatrogenically exacerbated brain hemorrhage may not be entirely avoidable, immediate anticoagulation of small- to moderatesized embolic strokes may be of overall benefit, if CT performed 24-48 h following stroke shows no hemorrhage. Patients with large embolic infarctions appear to be at special risk for delayed hemorrhagic transformation; postponing anticoagulation for 5-7 days may be judicious despite the continuing risk of recurrent embolism. Lumbar puncture with spinal fluid examination is not as sensitive as high-quality CT for detection of hemorrhagic infarction and is not routinely recommended prior to anticoagulation. Large, bolus doses of heparin and excessive anticoagulation should be avoided.