High rate of complete recanalization and dramatic clinical recovery duringtPA infusion when continuously monitored with 2-MHz transcranial Doppler monitoring

Background and Purpose-Clot dissolution with tissue plasminogen activator ( tPA) can lead to early clinical recovery after stroke. Transcranial Doppler (TCD) with low MHz frequency can determine arterial occlusion and monitor recanalization and may potentiate thrombolysis. Methods-Stroke patients receiving intravenous tPA were monitored during inf usion with portable TCD (Multigon 500M; DWL MultiDop-T) and headframe (Marc series; Spencer Technologies). Residual flow signals were obtained from th e clot location identified by TCD. National Institutes of Health Stroke Sca le (NIHSS) scores were obtained before and after tPA infusion. Results-Forty patients were studied (mean age 70+/-16 years, baseline NIHSS score 18.6+/-6.2, tPA bolus at 132+/-54 minutes from symptom onset). TCD m onitoring started at 125+/-52 minutes and continued for the duration of tPA infusion. The middle cerebral artery was occluded in 30 patients, the inte rnal carotid artery was occluded in 11 patients, the basilar artery was occ luded in 3 patients, and occlusions were multiple in 7 patients; 4 patients had no windows; and 1 patient had a normal TCD. Recanalization on TCD was found at 45+/-20 minutes after tPA bolus: recanalization was complete in 12 (30%) and partial in 16 (40%) patients. Dramatic recovery during tPA infus ion (total NIHSS score <3) occurred in 8 (20%) of all patients (baseline NI HSS range 6 to 22; all 8 had complete recanalization), Lack of improvement or worsening was associated with no recanalization, late recanalization, or reocclusion on TCD (C=0.811, P less than or equal to 0.01). Improvement by greater than or equal to 10 NIHSS points or complete recovery was found in 30% of all patients at the end of tPA infusion and in 40% at 24 hours. Imp rovement by greater than or equal to 4 NIHSS points was found in 62.5% of p atients at 24 hours. Conclusions-Dramatic recovery during tPA therapy occurred in 20% of all pat ients when infusion was continuously monitored with TCD, Recovery was assoc iated with recanalization on TCD, whereas no early improvement indicated pe rsistent occlusion or reocclusion. At 24 hours, 40% of all patients improve d by greater than or equal to 10 NIHSS points or recovered completely. Ultr asonic energy transmission by TCD monitoring may expose more clot surface t o tPA and facilitate thrombolysis and deserves a controlled trial as a way to potentiate the effect of tPA therapy.