Clinical Improvement at 24 Hours after MCA Occlusion Can be Predicted From the End of TPA Infusion NIH Stroke Scale Score
BACKGROUND: Recanalization precedes clinical improvement in patients treated with IV TPA. Transcranial Doppler (TCD) can assess the timing and degree of recanalization. We studied how the degree of recanalization and the NIH stroke scale (NIHSS) at the end of infusion correlated with short-term clinical improvement at 24 hours. Subjects and Methods: We evaluated consecutive IV TPA treated patients with anterior circulation ischemic symptoms, TCD evidence of occlusion, and serial NIHSS assessments (baseline, end of infusion, 24 hours post infusion). TCD was interpreted at the end of infusion using validated criteria for degree of recanalization. Changes in the NIHSS were defined as improvement (≥4 point improvement or complete resolution)or deterioration(decline of ≥2). Results: 52 patients met the criteria for inclusion (baseline NIHSS 17±6, median 18, range 5–29). By the end of infusion, NIHSS scores improved in 26 patients (50%). From the end of infusion to 24 hours, subsequent improvement by ≥4 points occurred in another 9 patients (17%), mostly in patients with partial recanalization (56%). NIHSS at end infusion correlated with NIHSS at 24 hrs in all patients (Adjusted R2=0.74). In patients with no recanalization, end-of-infusion NIHSS most highly predicted 24 hour scores (Adj.R2=.89) while correlation was less significant with partial(Adj.R2=.61) and complete(Adj.R2=.66) recanalization(all p<.00002). Deterioration following improvement at 24 hours was seen in 3 patients (2 reocclusions, 1 symptomatic hemorrhage). Conclusions: In patients with MCA occlusion, end of TPA infusion NIHSS scores accurately predict scores at 24 hours, especially in patients without vascular recanalization. This suggests that a majority of short term improvement occurs by the end of infusion. In patients without hemorrhagic transformation, deterioration of the NIHSS after infusion occurs mostly due to reocclusion.