Many patients with minor stroke are referred to outpatient clinics and are therefore not scanned immediately. A clinical rule is needed to identify patients who are likely to have intracerebral haemorrhage (ICH) and require urgent brain imaging, and patients who can safely start antiplatelet agents prior to scanning.
Methods: We determined clinical factors associated with ICH in 334 consecutive patients with minor stroke (NIHSS≤3) in the OXVASC Study, and derived a predictive model for ICH which was validated in a cohort of 280 patients presenting to a hospital-stroke clinic. Prognostic value was quantified as the area under the ROC curve (c statistics).
Results: The rate of ICH in minor stroke was 5.1% (95%CI 3.2-8.0%) in OXVASC, and 5.4% (3.3-8.7%) in the clinic cohort. Clinical factors predictive of ICH in OXVASC included BP on initial assessment ≥180/110mmHg (OR=14.5, 95%CI 1.8-114, p=0.001), vomiting (OR=15.7, 5.4-46, p<0.001), confusion (OR=8.2, 2.9-23, p<0.001), and anticoagulation use (OR=7.8, 2.2-28, p=0.006), and at least one predictive factor was identified in all 17 patients with ICH and in 35% overall; c statistic 0.92 (95% CI 0.88-0.97). Therefore, we derived the SCAN rule to identify ICH if ≥1 of the following were present: (S) systolic BP ≥180mmHg or diastolic BP ≥ 110mmHg, (C) confusion, (A) anticoagulation, (N) nausea and vomiting. In the clinic validation cohort, ≥1 predictive factor was identified in 14/15 of patients with ICH and in 24% overall; c statistic 0.87 (0.79-0.95).
Conclusion: The SCAN rule appears to be specific and sensitive at identifying ICH in an independent cohort of patients with minor stroke, although further independent validations are needed.