Thrombectomy 6 to 16 Hours After Ictus Is Beneficial

A paper by Albers et al published in the NEJM suggests that many more stroke victims can be saved from disability or death if they undergo removal of thrombi obstructing their internal carotid or proximal middle cerebral artery.

182 stroke patients with clots in major vessels were enrolled in the study.  They were last known to be well between 6 and 16 hours earlier and had diffusion and perfusion MRI scans upon admission to Emergency Room. Patients with proximal middle-cerebral-artery or internal-carotid-artery occlusion, and an initial infarct size of less than 70 ml, and a ratio of the volume of ischemic tissue on perfusion imaging to infarct volume of 1.8 or more were randomly assigned to endovascular therapy plus standard medical therapy or standard medical therapy alone. The primary outcome was the score on the modified Rankin scale (range, 0 to 6, with higher scores indicating greater disability) at day 90.  Ninety-two of these patients had clots removed, while the remaining 90 did not. 

The study found that the 90-day death rate was lower for patients who had a thrombectomy vs. those who did not – 14 percent vs. 26 percent.   The data also indicated that more pronounced was the rate of functional independence among the thrombectomy patients – 45 percent vs. 17 percent at 90 days after the procedure.

Endovascular thrombectomy for ischemic stroke plus standard medical therapy resulted in better functional outcomes than standard medical therapy alone among patients with proximal middle-cerebral-artery or internal-carotid-artery occlusion and a region of tissue that was ischemic but not yet infarcted.

Stent Retriever Therapy of Benefit to Stroke Patients

A multicenter trial the results of which were published in Radiology by Goyal et al indicated that if a patient with acute ischemic stroke is treated within two and half hours of ictus, 91% recover with little or no disability.  However after five and a half hours, favorable outcome goes down to 41%.

Data from 196 patients enrolled in the SWIFT PRIME trial, a global, multicenter, prospective study in which outcomes of patients treated with intravenous tissue plasminogen activator tPA alone or in combination with a thrombectomy device (Solitaire by Covidien, Irvine, CA) were analyzed.

In the stent retriever arm of the study, symptom onset to reperfusion time of 150 minutes or less led to 91% estimated probability of functional independence, which decreased by 10% over the next hour and by 20% with every subsequent hour of delay. Time from arrival at the emergency department to arterial access was 90 minutes (interquartile range, 69–120 minutes), and time to reperfusion was 129 minutes (interquartile range, 108–169 minutes). Patients who initially arrived at a referring facility had longer symptom onset to groin puncture times compared with patients who presented directly to an endovascular-capable center (275 versus 179.5 minutes, P < .001).

The findings of the trial strongly suggest that fast reperfusion leads to improved functional outcome among patients with acute stroke treated with stent retrievers and tPA.

Efficiencies Result in Better Outcomes in Patients with Strokes

Despite two decades of efforts to initiate therapy of patients with acute ischemic strokes (AIS) quickly, less than one-third of patients presenting with AIS in the United States, were treated within the guideline-recommended door-to-needle (DTN) time with tissue plasminogen activator (tPA).  Fonarow et al¹ article in JAMA discusses strategies that were implemented in a consortium of hospitals in order to reduce DTN time to 60 minutes or less for the initiation of thrombolysis with tPA in patients with acute ischemic strokes.

The Stroke initiative made recommendations to 1030 participating hospitals that treated 71 169 patients with AIS with tPA (27 319 during the pre-intervention period and 43 850 during the post-intervention period).  The quality stroke initiative included pre-notification of hospitals by emergency medical services (EMS), fast performance and interpretation of brain CT scans, immediate initiation of treatment for eligible patients, rapid feedback on performance and public recognition of high-performing hospitals.

Median DTN time for tPA administration declined from 77 minutes during the pre-intervention period to 67 minutes during the post-intervention period (P < .001). The DTN times for tPA administration of 60 minutes or less increased from 26.5% of patients during the pre-intervention period to 41.3% during the post-intervention period (P < .001). The annual rate of improvement in DTN times of 60 minutes or less increased from 1.36% per year pre-intervention to 6.20% per year post-intervention (P < .001). In-hospital all-cause mortality improved significantly from the pre-intervention to the post-intervention period from 9.93% to 8.25%, respectively (P < .001), symptomatic intracranial hemorrhage within 36 hours decreased from 5.68% to 4.68% (P < .001), and discharge to home was more frequent from 37.6% to 42.7% (P < .001).

Prior studies² have established that thrombolysis with tPA is effective when administered early with the goal being to initiate treatment within 60 minutes or less from the time patients arrive in the hospital.  The authors report that their initiative was associated with improved timeliness of thrombolysis following acute ischemic stroke on a national scale, and that this improvement was associated with lower in-hospital mortality and intracranial hemorrhage, along with an increase in the percentage of patients discharged home.

1.  Fonarow G, Zhao X, Smith E, Saver J et al. Door-to-Needle Times for Tissue Plasminogen Activator Administration and Clinical Outcomes in Acute Ischemic Stroke Before and After a Quality Improvement Initiative; JAMA. 2014;311(16):1632-1640.    doi:10.1001/jama.2014.3203.

2.  Hacke W, Donnan G, Fieschi C, Kaste M et al, Association of outcome with early stroke treatment: pooled analysis of ATLANTIS, ECASS, and NINDS rt-PA stroke trials. Lancet 2004 Mar 6; 363(9411): 768-74.

Ambulance-Based Thrombolysis in Acute Ischemic Stroke

Ebinger et al report in JAMA the result a specialized ambulance has in the initiation of treatment in patients with acute ischemic strokes.

Their study was conducted in Berlin, Germany over a 21 months period between 2011 and 2013 when a Stroke Emergency Mobile (STEMO) unit was dispatched every other week to care of patients with strokes. The STEMO was an ambulance equipped with a CT scanner, point-of-care laboratory, with telemedicine connection, a physician, a paramedic and an x-ray technician. Thrombolysis was started before transport to hospital if ischemic stroke was confirmed and contraindications excluded.  During the study period 6182 adult patients were included.

There was a reduction of 25-minutes in alarm-to-treatment times for STEMO compared to control weeks.  The 25-minute reduction was due to faster alarm-to-imaging and imaging-to-treatment intervals. Fifty eight percent of patients were treated within 90 minutes of onset versus 37% in the control.  The intervention also resulted in 33% patients treated with tPA versus 21% in the control.  STEMO deployment incurred no increased risk for intra-cerebral hemorrhage (7/200 vs 22/323); or 7-day mortality (9/199 versus 15/323).

A prior study by Walter et al¹ who also used a mobile stroke unit and treated patients with acute ischemic stroke with tPA safely within 70 to 80 minutes.

The authors conclude the use of ambulance-based thrombolysis resulted in decreased time to treatment without an increase in adverse events. 

1.  Walter S, Kostopoulos P,  Haass A et al. Diagnosis and treatment of patients with stroke in a mobile unit versus hospital: a randomized study controlled trial Lancet Neurol. 2012;11(5):397-404