• arterial occlusive disease;
  • computed tomography;
  • stroke;
  • thrombolytic therapy;
  • treatment outcome

Background Patients with moderate to severe acute ischemic stroke without intracranial vessel occlusion are an intriguing subset of stroke patients. They pose diagnostic and therapeutic challenges to the physician. We sought to study these patients with an emphasis on their radiological and clinical outcomes.

Methods This is a retrospective cohort study of ischemic stroke patients (NIHSS≥6), with no intracranial vessel occlusion on computed tomography angiography within six-hours of symptom onset. Follow-up imaging – either computed tomography brain or magnetic resonance imaging – was performed within one- to seven-days. The primary outcome was modified Rankin Scale score≤2 at three-months.

Results In a database of 1308 patients, we identified 99 (7·6%) patients with NIHSS≥6 and no intracranial vessel occlusion on computed tomography angiography. The mean age was 67·8 ± 15·4 years and 60 (60·6%) were men. The median baseline NIHSS was nine (6–28). The initial computed tomography head was normal in 79 (79·8%) patients. Dramatic early clinical improvement at 24 h (NIHSS score ≤2 at 24 h or change between baseline and 24 h NIHSS score ≥15 points) was seen in 38 (38·4%) patients. Follow-up scans showed infarcts in 66 (66·7%) patients. Fifty (50·5%) patients received tissue plasminogen activator; one (2%) tissue plasminogen activator-treated patient developed symptomatic intracranial hemorrhage. At three-months; 59 (59·6%) patients were independent (modified Rankin Scale≤2), 34 (34·3%) patients were dependent (modified Rankin Scale 3-5), and six (6·1%) were dead. The factors associated with the unlikelihood of good outcome were higher initial NIHSS (odds ratio 0·86 per additional point, 95% confidence interval 0·77–0·95, P=0·003), and older age (odds ratio 0·95 per additional year, 95% confidence interval 0·92–0·98, P=0·004).

Conclusion Stroke without intracranial occlusions are not a benign entity. Factors that are independently associated with decreased likelihood of a good outcome are higher baseline NIHSS, and older age. Treatment with tissue plasminogen activator is not a predictor of outcome.