Unlocking Paralysis

Macy Mills lies on a stretcher in the emergency department of Toronto Western Hospital, paralysed, as doctors and nurses hover above her. The 38-year-old triathlete and mother of three, who gave birth to her youngest child only five months ago, knows she has had a stroke. She remembers a dull headache that suddenly turned into a drill burrowing into one spot in her brain, sharp, hot and insistent. She was driving to her older children’s school to volunteer at their sports day.

Overcome by pain, and numb along her left side, instinct helped her lurch the car into a parking space and, after her mobile phone dropped to the floor, lean on the horn for help.

Now, no more than an hour later, a CT scan has shown that, like the majority of strokes, hers was ‘ischaemic’: a clot is blocking the arterial flow of blood to her brain. In her case, it is a large one on the right side, which is why the left side of her body is affected.

Dr Richard Farb, a neuroradiologist at Toronto Western Hospital, asks her husband to sign consent forms for a procedure that has not yet been tested in Canada. Macy will be the first

Canadian to undergo it.

This groundbreaking procedure is officially called an endovascular thrombectomy with a ‘stent retriever’ – a tiny wire mesh tube with an opening on one end. It was first tested in the Netherlands, while its first trials in Germany and Switzerland have proved promising, too. Its nickname, ‘Mr Clean’, reflects its ability to clean an artery out in 40 minutes or less.

What choice do I have? Macy thinks. She tries to nod and say, “Do what you have to.” The words come out muffled, as if she is speaking under water.

Within minutes of a local anaesthetic taking effect, she feels Farb puncturing a tiny hole in the femoral artery near her groin. He then uses radiographic imaging on a nearby screen to carefully thread a catheter that contains the stent up through her vascular system to the artery that feeds her brain.

At the opening of the artery, the catheter is retracted and Macy feels some pressure, as if someone is pinching her brain. It’s the stent, which has opened to envelop and trap the clot within the mesh.

“When is this going to be over?” she asks.

But it already is. Farb gently pulls the stent containing the clot out the same way it went in. From start to finish, the entire operation has lasted less than two hours.

“Try to move,” he says.

She lightly flexes the fingers of her left hand, which three hours ago could not hold on to her mobile phone.

Soon Macy is pumping breast milk in the intensive care unit, griping about the lack of a television set and feeling very, very lucky.


It is June 15, 2011. Three years and five months later, the Canadian trial of the ‘Mr Clean’ procedure, which involved 316 patients, ends early because it’s clear it’s already a success.

Dr Timo Krings, the head of neuroradiology at Toronto Western Hospital, explains it this way: “Before, surgical stroke treatment was a gamble. Anything we tried took at least two hours. Now, on the operating room table, we can see patients starting to speak again and move their limbs. And it’s fast. We’ve done one surgery in 14 minutes.

“I don’t say this lightly,” he continues. “Mr Clean is a game changer.”

Today clot retrieval is viewed as the choice procedure in Australia, New Zealand, Singapore, North America and Europe.

“For every five people you treat with clot retrieval, one more will go home able to function as an independent person, and there is one less person left severely dependent,” says Professor Alan Barber, director of the Auckland Hospital Stroke Service. Survivors are, essentially, picking up their lives where they left off.

The procedure requires a specialist team, and for this reason, is not available in all hospital emergency departments. Clot-retrieval centres are located in 19 hospitals across Australia, in Auckland, Wellington and Christchurch in New Zealand, while in Singapore there are currently three dedicated stroke centres. Barber says he would like to see more clot-retrieval centres established in tertiary hospitals. “It’s not the sort of thing you can do in a suburban hospital.”


Statistics show that every two seconds someone, somewhere, is having a stroke. Many may not realise it. They may feel dizzy for a few seconds or lose track of what they were saying but then they feel better.

But consider the number of stroke victims left paralysed or unable to speak. Of the estimated 15 million people worldwide who suffer a stroke each year, about six million die and five million are left permanently disabled. The number of deaths from AIDS, tuberculosis and malaria combined is about 3.5 million, much less than the stroke death rate.

It’s no surprise, then, that the mantra in the stroke universe is ‘Time is brain’ – neuro shorthand to remind specialists that in each minute after a stroke occurs, the brain will lose 1.9 million neurons, 14 billion synapses and 12 kilometres worth of axonal fibres if they were strung out in a line.

Associate Professor Bruce Campbell, chair of the Australia-based Stroke Foundation Clinical Council, stresses that people need to recognise the sign of stroke and get to hospital quickly.

Ever since the drug tPA, or tissue plasminogen activator, was introduced in the mid-1990s as a clot-buster, it has been the stroke treatment of choice, albeit in a limited number of cases because it must be administered within 3 to 4.5 hours of a stroke occurring and can take hours to work.

Surgeons have tried other devices as alternatives or complements – anything that could open a vessel more quickly and get rid of the blockage. They looked familiar, too, such as a chimney sweep brush in miniature or a tiny butterfly net.

“It got to the point that at an international conference seven years ago, a new catch device was presented at every lecture in the stroke session,” says Krings. “At the end, I said, ‘If any of you were right, we’d have only one.’”

At around that same time, German neuroradiologist Professor Hans Henkes was working on a patient who had had a stroke that left a clot in her middle cerebral artery. He decided to use a device he’d co-developed for the stent-assisted coil treatment of an aneurysm. When he pulled out the stent that was keeping the artery open as he operated, the clot came with it, intact.

At a conference soon after, Henkes mentioned it to some colleagues, who agreed it was promising. So began trials in Europe, with Dr Vitor Mendes Pereira, then the head of interventional radiology at the University of Geneva, as one of the principal investigators. They learned they needed a vessel that was at least two millimetres wide within which to work and that it was not effective on haemorrhagic strokes, or ‘bleeders.’

And while they initially thought they had a short window of time to clean a vessel out, they have since learned that each case depends on the quality and duration of the ‘collaterals’, where the brain temporarily compensates for a blocked vessel by finding a detour for the blood to flow. It can last minutes, or hours, or possibly even a day.


Wolfgang Kahnke, a retired toolmaker, recalls being cranky as he drove to his appointment with the surgeon who’d replaced his knee two years earlier. For the 72-year-old grandfather of two, it was a check-up, nothing more, and he arrived early, hoping he could somehow be fitted in. After all, he had a dinner date with his wife, Karin, that night.

As he waited for the surgeon in the examination room, he felt something humming in his head, not painful, exactly, but uncomfortable.

Walk it off, he told himself.

But he couldn’t move.

When an emergency CT scan showed a large clot blocking the main artery right at the back of his neck, Kahnke was taken to the operating room within the hour.

The next day, he took a shower unaided. As the water sluiced over him, he thought, I’ve never felt so alive. Then he shivered at how close he’d come.

Mr Clean, his doctors said, was the difference between him dying or ending up being paralysed from the neck down for the rest of his life. For Kahnke, it meant being able to play Santa Claus at Christmas for the children of employees at his former company.

“I make a pretty good Santa,” he says, pointing to his cloud of white hair and his beard. “Only, I’m not so big!”


For Macy Mills, now a private banker with an international financial services company, the only visible reminders of her stroke are the three pills she takes every evening: a beta blocker, an ACE inhibitor and a blood thinner. These medications were prescribed when tests revealed that the apex of her heart is composed of scar tissue where blood can pool, which increases the risk of clots forming.

Mills also now has an internal defibrillator, the result of having suffered a cardiac arrest in May 2015. Slim, fit and driven, the former triathlete chafes at not being able to run a seven-minute mile any more. But she is grateful that, thanks to Mr Clean, she’s able to be there for her family.

Signs of stroke may include

  • Sudden weakness and/or numbness of the face, arm or leg, especially on one side of the body

  • Sudden confusion or trouble speaking and understanding
  • Sudden vision problems
  • Sudden severe or unusual headaches
  • Sudden dizziness, loss of balance or coordination, or trouble walking
  • Sudden droopiness in the face

If you have any of these signs, call emergency services right away.

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