The presence of a right-to-left shunt is associated with dramatic improvement after thrombolytic therapy in patients with acute ischemic stroke.

BACKGROUND AND PURPOSE The efficacy of pharmacological thrombolysis using tissue plasminogen activator depends on the relative fibrin content of the thrombus. We investigated whether patients with stroke with a right-to-left shunt (RLS), whose embolic source was associated with fibrin-rich thrombus formed in the venous system, were more likely to improve dramatically after thrombolytic therapy than those without RLS. METHODS Patients with acute stroke treated with tissue plasminogen activator were assessed prospectively to determine the clinical factors associated with "dramatic improvement" after tissue plasminogen activator administration. "Dramatic improvement" was defined as a >/=10-point reduction in the total National Institutes of Health Stroke Scale score or a total National Institutes of Health Stroke Scale score of 0 or 1 at 7 days. The presence of an RLS was determined using contrast transcranial Doppler within 6 hours of stroke onset. RESULTS Forty-four patients (26 males; mean age; 73.0+/-10.7 years; baseline National Institutes of Health Stroke Scale score,13.4+/-6.6) were enrolled. Twenty-one patients had dramatic improvement (D group). Contrast transcranial Doppler demonstrated an RLS in 17 (35.4%) patients. On multivariate logistic regression analysis using hyperlipidemia, atrial fibrillation, RLS, DWI-ASPECTS (>8), baseline National Institutes of Health Stroke Scale score (<10), and glucose (<120 mg/dL) as variables with a P<0.1 on univariate analysis, RLS (OR, 5.9; CI,1.3 to 27.3; P=0.022) was the only independent factor associated with dramatic improvement. CONCLUSIONS The presence of an RLS on contrast transcranial Doppler was an independent factor associated with dramatic improvement after tissue plasminogen activator administration.