米国における advanced practice のための大学院教育

広島大学大学院保健学研究科 第1回国際シンポジウ

NIH Stroke Scale as a Predictor of Clot Presence, Location, and Persisting Occlusion in Candidates for Thrombolysis

Background: In acute stroke, few tools are readily available to determine clot presence and location before thrombolysis, nor whether occlusion persists after intravenous TPA. Because the NIH Stroke Scale (NIHSS) is easily obtained in the Emergency Department, we correlated sequential NIHSS scores and arterial occlusion in prospective candidates for IV TPA. Methods: Potential thrombolysis patients evaluated with transcranial Doppler (TCD) ultrasound and the NIHSS at the time of presentation were studied. TCD was performed using previously validated criteria for clot detection, localization, and subsequent degree of recanalization after thrombolysis. In patients treated at (0.9 mg/kg), repeat NIHSS scores and diagnostic TCD were performed at the end of infusion. Results: 119 ischemic stroke patients met inclusion criteria (age 68±15, NIHSS 15±7, median 14, range 2–36), with 83% having occlusion consistent with symptoms. Occlusion was present in all patients with NIHSS ≥22, none with NIHS

Timing of Recanalization After Tissue Plasminogen Activator Therapy Determined by Transcranial Doppler Correlates With Clinical Recovery From Ischemic Stroke

Background—The duration of cerebral blood flow impairment correlates with irreversibility of brain damage in animal models of cerebral ischemia. Our aim was to correlate clinical recovery from stroke with the timing of arterial recanalization after therapy with intravenous tissue plasminogen activator (tPA). Methods—Patients with symptoms of cerebral ischemia were treated with 0.9 mg/kg tPA IV within 3 hours after stroke onset (standard protocol) or with 0.6 mg/kg at 3 to 6 hours (an experimental institutional review board–approved protocol). National Institutes of Health Stroke Scale (NIHSS) scores were obtained before treatment, at the end of tPA infusion, and at 24 hours; Rankin Scores were obtained at long-term follow-up. Transcranial Doppler (TCD) was used to locate arterial occlusion before tPA and to monitor recanalization (Marc head frame, Spencer Technologies; Multigon 500M, DWL MultiDop-T). Recanalization on TCD was determined according to previously developed criteria. Results—Forty patients were studied (age 70±16 years, baseline NIHSS score 18.6±6.2). A tPA bolus was administered at 132±54 minutes from symptom onset. Recanalization on TCD was found at the mean time of 251±171 minutes after stroke onset: complete recanalization occurred in 12 (30%) patients and partial recanalization occurred in 16 (40%) patients (maximum observation time 360 minutes). Recanalization occurred within 60 minutes of tPA bolus in 75% of patients who recanalized. The timing of recanalization inversely correlated with early improvement in the NIHSS scores within the next hour (polynomial curve, third order r2=0.429, P300 minutes. Conclusions—The timing of arterial recanalization after tPA therapy as determined with TCD correlates with clinical recovery from stroke and demonstrates a 300-minute window to achieve early complete recovery. These data parallel findings in animal models of cerebral ischemia and confirm the relevance of these models in the prediction of response to reperfusion therapy

Deterioration Following Spontaneous Improvement

Background and Purpose—Some stroke patients will deteriorate following improvement (DFI), but the cause of such fluctuation is often unclear. While resolution of neurological deficits is usually related to spontaneous recanalization or restoration of collateral flow, vascular imaging in patients with DFI has not been well characterized. Methods—We prospectively studied patients who presented with a focal neurological deficit that resolved spontaneously within 6 hours of symptom onset. Patients were evaluated with bedside transcranial Doppler (TCD). Digital subtraction angiography (DSA), computed tomographic angiography (CTA), or magnetic resonance angiography (MRA) were performed when feasible. DFI was defined as subsequent worsening of the neurological deficit by ≥4 National Institutes of Health Stroke Scale points within 24 hours of the initial symptom onset. Results—We studied 50 consecutive patients presenting at 165±96 minutes from symptom onset. Mean age was 61±14 years; 50% were females. All patients had TCD at the time of presentation, and 68% had subsequent angiographic examinations (DSA 10%, CTA 4%, and MRA 44%). Overall, large-vessel occlusion on TCD was found in 16% of patients (n=8); stenosis was found in 18% (n=9); 54% (n=27) had normal studies; and 6 patients (12%) had no temporal windows. DFI occurred in 16% (n=8) of the 50 patients: in 62% of patients with TCD and angiographic evidence of occlusion, in 22% with stenosis, and in 4% with normal vascular studies (P Conclusions—DFI is strongly associated with the presence of large-vessel occlusion or stenosis of either atherosclerotic or embolic origin. Normal vascular studies and lacunar events were associated with stable spontaneous resolution without subsequent fluctuation. Urgent vascular evaluation may help identify patients with resolving deficits and vascular lesions who may be candidates for new therapies to prevent subsequent deterioration

High Rate of Complete Recanalization and Dramatic Clinical Recovery During tPA 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 infusion with portable TCD (Multigon 500M; DWL MultiDop-T) and headframe (Marc series; Spencer Technologies). Residual flow signals were obtained from the clot location identified by TCD. National Institutes of Health Stroke Scale (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 monitoring started at 125±52 minutes and continued for the duration of tPA infusion. The middle cerebral artery was occluded in 30 patients, the internal carotid artery was occluded in 11 patients, the basilar artery was occluded 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 infusion (total NIHSS score Conclusions—Dramatic recovery during tPA therapy occurred in 20% of all patients when infusion was continuously monitored with TCD. Recovery was associated with recanalization on TCD, whereas no early improvement indicated persistent occlusion or reocclusion. At 24 hours, 40% of all patients improved by ≥10 NIHSS points or recovered completely. Ultrasonic energy transmission by TCD monitoring may expose more clot surface to tPA and facilitate thrombolysis and deserves a controlled trial as a way to potentiate the effect of tPA therapy