The miracle procedure unlocking paralysis
Meet 'Mr Clean'
Image via Med Scape
Macy Mills lies on a stretcher 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’s 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. Overcome by pain and numb along her left side, instinct helped her lurch her car into a parking space and lean on the horn for help.
Now, no more than an hour later, a scan has shown that like the majority of strokes, hers was “ischemic”: a clot is blocking the arterial flow of blood to her brain. It’s a large one on the right side, which is why the left side of her body is affected.
Neuroradiologist Dr Richard Farb asks her husband to sign consent forms for a procedure that hasn’t yet been tested in Canada. Officially called an endovascular thrombectomy with a “stent retriever”—a tiny wire mesh tube with an opening on one end—its first trials have proved promising. Its nickname, “Mr Clean”, sums up its ability to clean an artery out in 40 minutes or less.
Within minutes of a local anesthetic, Macy feels Dr Farb puncturing a tiny hole in the femoral artery near her groin. He then uses radiographic imaging to carefully thread a catheter 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. From start to finish, the entire operation lasted less than two hours.
She lightly flexes the fingers of her left hand, which three hours ago couldn’t hold onto her mobile. Soon she’s pumping breast milk in the intensive care unit.
Three years later, the Canadian “Mr. Clean” trial, which involved 316 patients, ends early because it’s clear it’s already a success.
A game-changing procedure
Image via Cleveland Clinic
The procedure has been approved since 2011 in Europe and North America. It has doubled the survival rate, with just one patient death in every ten.
Dr Timo Krings, the head of neuro-radiology at Toronto Western Hospital, Canada, puts 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. We did one surgery in 14 minutes. Mr Clean is a game changer.”
Of the estimated 15 million people worldwide who suffer a stroke each year, about five million die and six million are left permanently disabled. The number of deaths from Aids, tuberculosis and malaria combined totals about 3.5 million, much less than the stroke death rate.
Each minute after a stroke occurs, the brain will lose 1.9 million neurons, 14 billion synapses and seven miles worth of axonal fibres if they were strung out in a line.
Ever since the drug tPA, or tissue plasminogen activator, was introduced in the mid-1990s as a clot-buster, it’s been the stroke treatment of choice. Surgeons have tried other devices as alternatives—anything that could open a vessel more quickly and get rid of the blockage. “It got to the point that at an international conference six years ago, a new catch device was presented at every lecture in the stroke session,” Krings recalls.
Around that same time, German neuroradiologist 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.
The trials begin…
Image via Cure Health
At a conference soon after, Henkes mentioned it to some colleagues, who agreed it was promising. So began a trial in Europe. The researchers soon learned they needed a vessel that was at least two millimetres wide within which to work and that it wasn’t effective on hemorrhagic strokes, or “bleeders”.
While they initially thought they had a short time window to clean a vessel out, they have since learned that each case depends on the quality and duration of the “collaterals”, where the brain compensates for a blocked vessel by finding a detour for the blood to flow. It can last minutes, or hours, or even a day.
“We were pioneers and a lot of people… were rather sceptical,” primary researcher Vitor Mendes Pereira recalls. “But the results spoke for themselves.”
For Macy Mills, now 43, 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.
Slim, fit and driven, the former triathlete chafes at not being able to run a seven-minute mile anymore. But she’s grateful that, thanks to Mr Clean, she’s able to be there for her family.