Intravenous thrombolysis (IVT) in patients with a low National Institutes of Health Stroke Scale (NIHSS) score of 0-5 remains controversial. IVT should be used in patients with mild but nevertheless disabling symptoms. We hypothesize that response to IVT of patients with "mild stroke" may depend on their level of functional dependence (FD) at hospital admission. The aims of our study were to investigate the effect of IVT and to explore the role of FD in influencing the response to IVT. This study was a retrospective analysis of a prospectively collected database, including 389 patients stratified into patients receiving IVT (IVT+) and not receiving IVT (IVT -) just because of mild symptoms. Barthel index (BI) at admission was used to assess FD, dividing subjects with BI score < 80 (FD+) and with BI score > 80 (FD-). The efficacy endpoints were the rate of positive disability outcome (DO+) (3-month mRS score of 0 or 1), and the rate of positive functional outcome (FO+) (mRS score of zero or one, plus BI score of 95 or 100 at 3 months). At the multivariate analysis, IVT treatment was an independent predictor of DO+ (OR 3.12, 95% CI 1.34-7.27, p = 0.008) and FO+ (OR: 4.70, 95% CI 2.38-9.26, p = 0.001). However, FD+ IVT+ patients had a significantly higher prevalence of DO+ and FO+ than those FD+ IVT-. Differently, IVT treatment did not influence DO+ and FO+ in FD- patients. In FD+ patients, IVT treatment represented the strongest independent predictor of DO+ (OR 6.01, 95% CI 2.59-13.92, p = 0.001) and FO+ (OR 4.73, 95% CI 2.29-9.76, p = 0.001). In conclusion, alteplase seems to improve functional outcome in patients with "mild stroke". However, in our experience, this beneficial effect is strongly influenced by FD at admission.
Keywords: Barthel index; Keywords: intravenous thrombolysis; NIHSS; functional dependence.