Endovascular Therapy: Every Minute Counts

Small improvements in treatment delays for endovascular therapy-even less than a minute-can make a big difference in outcomes after ischemic stroke, suggests a study published online in Neurology.

The study found that decreasing treatment delays by just one minute may contribute to 4.2 additional days of healthy life. Decreasing treatment delays by 20 minutes may amount to three months of added disability-free life.

“We demonstrated that every minute counts when one intervenes with endovascular therapy, even more so than for tPA [tissue plasminogen activators] alone. On average, patients gain many days of healthy life for every minute saved in delivering the therapy while the more severe strokes can gain a week or more with each minute saved. Patients with long life expectancies stand to gain and lose more: a young patient with a severe stroke can lose 2 years of healthy life with every hour the endovascular therapy is delayed,” wrote first author Atte Meretoja, MD, PhD, MSc, FRACO, of Helsinki University Hospital and the University of Melbourne (Parkville, Australia), and colleagues.

Endovascular therapy, a minimally invasive surgical technique used to re-canalize occluded vessels, has become the new gold standard for large artery occlusion in ischemic stroke. However, like treatment with tPA, the effectiveness of endovascular therapy relies heavily on how quickly patients can be treated.

To estimate just how much treatment delays impact the effectiveness of endovascular therapy, researchers constructed a model using data from various sources: an observational study, a pooled analysis of randomized controlled trials, survival data for the general Finnish population, Helsinki thrombolysis registry data, and weighted disability data. The analysis included 2474 stroke patients treated with IV thrombolysis in Helsinki, Finland between 1998-2014. Of these, 1745 received tPA alone and 729 were eligible for endovascular therapy. Using three-month outcomes, researchers calculated expected lifetimes and cumulative long-term disability for incremental delays in treatment.

Key Results:

• For each minute saved in time to treatment, patients gained 4.2 days of healthy life (95% prediction interval 2.3–5.4)

♦ Women had longer life expectancies and had slightly higher gains than men

♦ Patients under age 55 years who had severe stroke (NIH Stroke Scale score > 10) gained over a week for each minute saved

• Overall, for every 20 minutes saved in time to treatment, patients gained an average of three months of disability-free life

The authors emphasized these results represent average gains based on population level analyses. Individual gains may be more or less, depending on individual characteristics like collateral circulation, success of reperfusion, and complications.

They also stressed the importance of streamlining tPA delivery and endovascular treatment.

“As endovascular services are being set up around the world, time needs to be taken into account as a critical component of service design. As imaging requirements in endovascular patient selection are more complex, special attention should be given to streamlining the acute imaging protocols. Our findings should promote the rational allocation of endovascular services and ambulance transfer patterns,” they concluded.

The authors noted that modeling data came from a Finnish observational cohort with experience in stroke thrombolysis. Results may not extend to less specialized centers.

Take-home Points

• A Finnish modeling study found that for each minute saved in time to endovascular therapy in ischemic stroke, patients gained 4.2 days of healthy life.

• For every 20 minutes saved in time to treatment, patients gained an average of 3 months of disability-free life.

• Younger patients with more severe strokes may lose as much as two years of healthy life for every hour of treatment delay.

• Results highlight the importance of streamlining tPA and endovascular treatment in ischemic stroke.

One or more authors reports speakers’ fees, consulting, advisory board membership, research contracts X for one or more of the following: Siemens, Boehringer Ingelheim, Stryker, Nestle, Phagenesis, Bayer, Pfizer, Lumosa Pharm, Medfield Diagnostics, BrainsGate, and/or Portola Pharmaceuticals.

Reference: Meretoja A, et al. Endovascular therapy for ischemic stroke: save a minute-save a week. Neurology. 2017 Apr 28.