Protocol speeds thrombectomy stroke patients from primary centers

HOUSTON – A novel protocol designed to speed patients with large-vessel occlusion strokes in and out of primary stroke centers and on to centers where they can undergo definitive thrombectomy treatment produced significant improvements in treatment speed and outcomes among 22 Rhode Island patients managed with the full protocol.

Streamlining the path in and out of a primary stroke center is key for delivering mechanical thrombectomy as quickly as possible to patients with an emergent large vessel occlusion, said Ryan A. McTaggart, MD, at the International Stroke Conference sponsored by the American Heart Association. “Door-in door-out time should be the standard metric for all partnerships between primary and comprehensive stroke centers,” said Dr. McTaggart, a neuroradiologist at Rhode Island Hospital in Providence, the state’s only comprehensive stroke center.

^{Mitchel Zoler/Frontline Medical News}

Dr. Ryan A. McTaggart

• When a patient with a suspected large vessel occlusion with a Los Angeles Motor Score of 4 or 5 arrives soon after onset at the primary stroke center, a call immediately goes out to the EMS transfer center of Rhode Island Hospital to coordinate the transport that will move the patient from the primary center to the comprehensive when needed.

• The initial CT scan at the primary center is run as the definitive scan, including a conventional CT scan to rule out hemorrhage and allow intravenous thrombolytic therapy with tissue plasminogen activator (TPA) and CT angiography to locate the occluding clot.

• The CT images are immediately uploaded to a cloud-based library so that neurologists at Rhode Island Hospital can read the images on their phones and plan the management strategy.

During the 11 months following the start of the protocol, the Rhode Island network identified 70 patients as candidates for thrombectomy, including 22 managed using the complete protocol and 48 managed using only parts of the new protocol.

The median time from onset of stroke symptoms to revascularization with thrombectomy was 184 minutes in the 22 patients managed under the full protocol and 233 minutes among 48 similar patients who were not fully managed with the protocol, Dr. McTaggart reported. This “dramatic” difference in median times was entirely driven by a difference in the door-in door-out time at the primary stroke center, which was a median of 64 minutes for the 22 patients managed with the full protocol and a median of 104 minutes without the full protocol, a 38% relative decrease that was statistically significant.

Time to initiation of intravenous TPA at the primary stroke center also improved, from a median of 65 minutes without the full protocol to a median of 40 minutes with it, a statistically significant difference. “The primary stroke center physicians tell us they have greater confidence to start TPA when they have a consult that can identify the patient’s clot,” he said.

Consistent with the shorter time to revascularization, the prevalence after 90 days of a functionally good outcome – a modified Rankin scale score of 0-2 – occurred in 50% of patients managed with the full protocol and 25% of those managed with a partial protocol, a statistically significant difference.

To put the 184 minutes median time from stroke onset to reperfusion into perspective, Dr. McTaggart noted that it is comparable to the time to reperfusion documented recently in a U.S. registry of thrombectomy patients who had been transported directly to the comprehensive stroke centers where their thrombectomy was done.

He also acknowledged the heavy lifting he and his associates had to do to set up this network. Getting buy-in from all the regional primary strokes centers was “a ton of work,” Dr. McTaggart said in an interview. “We told the primary stroke center staffs that thrombectomy is a powerful treatment, with a number needed to treat of three to get one improved outcome. That’s a convincing argument. The thrombectomy data [that became available in early 2015] made the argument for the protocol and network more compelling.”

Primary stroke centers keep the stroke patients who don’t have a clot occlusion suitable for thrombectomy, which means the comprehensive center thrombectomy team receives fewer false-alarm patients. Dr. McTaggart’s current goal is to have primary stroke centers get incoming patients out and on the road to a thrombectomy center within 45 minutes. In the future, primary stroke centers will perform CT imaging on all patients with suspected strokes, not just the severely affected patients with a Los Angeles Motor Score of 4 or 5. Additional useful steps toward speeding appropriate stroke patients to thrombectomy is direct ambulance transport of selected, high probability patients directly to a comprehensive stroke center and use of mobile stroke units to bring CT imaging and the start of TPA treatment out into the field.

Dr. McTaggart had no disclosures.

mzoler@frontlinemedcom.com

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