EVT will save millions of lives from stroke. Eventually.

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Kris Walterson doesn't remember exactly how he got to the bathroom, very early one Friday morning - only that once he was there, his feet wouldn't obey him. He crouched down and tried to lift them with his hands before sliding to the ground. He didn't feel panicked by the problem, or even really nervous. But when he tried to get up, he kept falling back: banging his back against the tub, making a din of cupboard doors. It didn't make sense to him then, why his legs didn't lock into place under him. He had a pair of fluffy socks on and he tried to pull them off, thinking bare feet might have better traction on the bathroom floor. That didn't work either.

When his mother came out of his room to investigate the noise, he tried to tell her he couldn't stand up, that he needed her help. But he couldn't get her to understand, and instead of hoisting him up, she called 911. After he was loaded into an ambulance at his home in Calgary, Alberta, a paramedic warned him he was going soon hear the sirens, and he did. The sound is one of the last things he remembers from that morning.

Walterson, who was 60, suffered from a severe ischemic stroke - the type d Stroke caused by a blockage, usually a blood clot, in a blood vessel in the brain. The ischemic variety accounts for approximately 85% of all strokes. The other type, hemorrhagic stroke, is a yin for ischemic yang: while a blockage prevents blood flow to parts of the brain, depriving it of oxygen, hemorrhage means blood is released, flowing when and where it should not. In either case, too much or too little blood, the result is the rapid death of the affected brain cells.

When Walterson arrived at Foothills Medical Center, a large hospital from Calgary, he was rushed to the imaging department, where CT scans confirmed the existence and location of the clot. It was an M1 occlusion, meaning a blockage in the first and largest branch of his middle cerebral artery.

If Walterson had suffered his accident stroke a few years earlier, or on the same day in another part of the world, his prognosis would have been completely different. Instead, he received a newly developed treatment, established in part by the Foothills neurology team: something called endovascular thrombectomy, or EVT. In the hospital's angiography room, a neuroradiologist, guided by X-ray imaging, punctured Walterson's femoral artery at the top of her inner thigh and threaded a microcatheter through her body, north to the brain. The clot was extracted from his middle cerebral artery and removed through the incision in his groin. Just like that, blood flow was restored, and soon his symptoms were all but gone.

Just over 24 hours later, Walterson's memory resumed. hair of the beast, while lying in a cramped bed in the stroke room. He had breakfast. He answered questions from the stroke team doctors during their rounds. On Sunday afternoons, he managed to wander around the ward, cracking jokes while a colleague in stroke neurology hovered nearby. “Do you want to hold my hand? she asked. "People will talk," he replied, and dragged himself along. It wasn't until Monday afternoon, as he was lacing up his black trainers and preparing to head home, that he asked fellow stroke specialist Dr Kimia Ghavami how well he was doing. Friday during those hours he couldn't remember. p>

"When I met you," she said, "you were completely paralyzed on your left side." Without the EVT, Walterson probably would have faced a better case of weeks in the hospital and months of rehabilitation. Worst case scenario, if he survived: a feeding tube, permanent immobilization and a very shortened life in a bed in a long-term care facility. It could have been catastrophic, but there he was, hearing of his now gone symptoms.

A stroke kills an estimated six and a half million people around the.. .