Doctor Thalia Field in her office


Stroke researcher rolls with COVID-19 punches

Dr. Thalia Field keeps her eye on the goal as she adapts clinical trial to pandemic reality

Chapter 1 A sudden spotlight

Dr. Thalia Field didn’t expect to be doing media interviews about her field of expertise, a rare type of stroke called cerebral venous thrombosis or CVT.

But earlier this year CVT was in the news, as reports emerged of a rare blood clotting complication potentially linked to one of the new COVID-19 vaccines. Suddenly Dr. Field was called on as a leading CVT expert.

For the stroke neurologist and researcher, who holds the Sauder Family and Heart & Stroke BC & Yukon Professorship in Clinical Stroke Research, this was not the first curve the pandemic had thrown at her.

CVT occurs when a blood clot blocks a vein draining blood from the brain. Diagnosing it is difficult because symptoms — such as a severe headache and blurred vision — differ from the most typical signs of stroke.

CVT affects mostly women, most of them under 50. It accounts for about 1% of all strokes. About 85% of people are functionally independent after CVT, but half experience long-term issues with cognition, pain, fatigue or mood, which may leave them unable to return to work or school.

“Because CVT is rare and because these tend to be younger and higher functioning stroke survivors, there are so many questions that aren't answered,” says Dr. Field.

Chapter 2 Going virtual

Dr. Field set to work trying to find some of those answers, launching a clinical trial in 2019 with support from Heart & Stroke donors.

The trial is testing a new blood thinning medication as a treatment. It is also breaking ground by documenting the experience of people with CVT, including emotional and social impacts.

The rarity of CVT forced Dr. Field and her team to integrate video conferencing and phone communications into their plans from the start.

“The question was, how do we include as many people as possible with the disease?” she says. The answer was using technology to communicate with some participants who live far from major hospitals. This also allowed the researchers to include people who are often underrepresented in research, such as younger women managing family commitments, jobs and more, Dr. Field adds.

Then in early 2020, the pandemic hit. Suddenly, the entire trial had to go virtual.

“We were lucky that we had a framework,” Dr. Field says. “We had to make some adaptations, say, learning more about some of our more detailed cognitive assessments and what accommodations we would need to make online. But certainly, we were ready.”


of people are functionally independent after CVT

Chapter 3 What’s next

As the trial continues, she says, “There are elements that people will need to come to hospital for; we can't conduct a brain scan remotely. But a lot of the assessments are being done virtually.”

Meanwhile, like most healthcare providers, Dr. Field had to adapt her clinical practice with stroke patients at Vancouver General Hospital to the realities of physical distancing.

Virtual appointments make it easier to provide followup care for patients who live remotely or have difficulty getting to the hospital, she says. Challenges with virtual care include lack of technology or internet access. “For some of my patients in more remote communities in the North, that’s a real challenge,” she says.

Still, Dr. Field sees huge potential for virtual care, especially for increasing access to stroke rehabilitation services. “I think virtual care has been an under-tapped resource for so long. Trying to access outpatient rehab has been a challenge for many of our patients.”

As for her research, the sudden headlines about COVID vaccines and blood clots added a new urgency.

She is working with CVT researchers around the world, collaborating with experts in public health and vaccine safety. “We’ve set up an international monitoring project, to learn more about the cases that may be in association with the vaccine.”

She sees this as an opportunity both to raise awareness about CVT and to advance knowledge about the disease, as more is learned about the people who are affected.