Effect of the Use of Ambulance-Based Thrombolysis on Time to Thrombolysis in Acute Ischemic Stroke : A Randomized Clinical Trial

Abstract

Time to thrombolysis is crucial for outcome in acute ischemic stroke. To determine if starting thrombolysis in a specialized ambulance reduces delays. In the Prehospital Acute Neurological Treatment and Optimization of Medical care in Stroke Study (PHANTOM-S), conducted in Berlin, Germany, we randomly assigned weeks with and without availability of the Stroke Emergency Mobile (STEMO) from May 1, 2011, to January 31, 2013. Berlin has an established stroke care infrastructure with 14 stroke units. We included 6182 adult patients (STEMO weeks: 44.3% male, mean [SD] age, 73.9 [15.0] y; control weeks: 45.2% male, mean [SD] age, 74.3 [14.9] y) for whom a stroke dispatch was activated. The intervention comprised an ambulance (STEMO) equipped with a CT scanner, point-of-care laboratory, and telemedicine connection; a stroke identification algorithm at dispatcher level; and a prehospital stroke team. Thrombolysis was started before transport to hospital if ischemic stroke was confirmed and contraindications excluded. Primary outcome was alarm-to-thrombolysis time. Secondary outcomes included thrombolysis rate, secondary intracerebral hemorrhage after thrombolysis, and 7-day mortality. Time reduction was assessed in all patients with a stroke dispatch from the entire catchment area in STEMO weeks (3213 patients) vs control weeks (2969 patients) and in patients in whom STEMO was available and deployed (1804 patients) vs control weeks (2969 patients). Compared with thrombolysis during control weeks, there was a reduction of 15 minutes (95% CI, 11-19) in alarm-to-treatment times in the catchment area during STEMO weeks (76.3 min; 95% CI, 73.2-79.3 vs 61.4 min; 95% CI, 58.7-64.0; P < .001). Among patients for whom STEMO was deployed, mean alarm-to-treatment time (51.8 min; 95% CI, 49.0-54.6) was shorter by 25 minutes (95% CI, 20-29; P < .001) than during control weeks. Thrombolysis rates in ischemic stroke were 29% (310/1070) during STEMO weeks and 33% (200/614) after STEMO deployment vs 21% (220/1041) during control weeks (differences, 8%; 95% CI, 4%-12%; P < .001, and 12%, 95% CI, 7%-16%; P < .001, respectively). STEMO deployment incurred no increased risk for intracerebral hemorrhage (STEMO deployment: 7/200; conventional care: 22/323; adjusted odds ratio [OR], 0.42, 95% CI, 0.18-1.03; P = .06) or 7-day mortality (9/199 vs 15/323; adjusted OR, 0.76; 95% CI, 0.31-1.82; P = .53). Compared with usual care, the use of ambulance-based thrombolysis resulted in decreased time to treatment without an increase in adverse events. Further studies are needed to assess the effects on clinical outcomes. clinicaltrials.gov Identifier: NCT01382862.