Timo Krings


“The most profound and scaring changes I felt are the impact of increased levels of anxiety and stress on the team,” comments Timo Krings regarding his learnings from COVID-19, which has had a considerable impact on his, and everyone else’s, neurointerventional practice. Krings is currently serving as a professor of radiology and surgery, and programme director of interventional neuroradiology at the Department of Medical Imaging at the University of Toronto (Toronto, Canada). Krings talks to NeuroNews about exciting developments the future might hold for neuroradiology, noting that it would be amazing to one day integrate neuromodulation and neurointervention using ‘stentrodes’.

What initially attracted you to medicine and neuroradiology?

I majored in biology and philosophy and was particularly interested in the interplay between these two fields. When reading Popper and Eccles’ millennial work The Self and its Brain I decided to study medicine, and to move into the neurosciences. I was lucky to study one year abroad at Harvard Medical School where, during my neurology rotation, I witnessed an intra-arterial urokinase thrombolysis done by In Sup Choi at Massachusetts General Hospital in Boston, USA. I remember asking my senior staff at this time what type of specialty you have to pursue to do these types of treatment, and he answered, “interventional neuroradiology”, and the rest is history.

Who were your mentors and what impact have they had on your career?

The three main names that come to mind are: Armin Thron, neuroradiologist in Aachen, Germany, a specialist in spinal vascular anatomy and malformations; the late Pierre Lasjaunias in Bicetre, Paris, France, with whom I did my interventional fellowship (and where I worked as junior staff); and Karel Terbrugge, my predecessor in Toronto who epitomised the successful combination of a diagnostic and interventional neuroradiologist.

All three were extremely generous teachers who not only taught neuroradiology in all its facets, but also ethics and leadership by example. While I am indebted to the above mentioned giants, I have learned also a lot from colleagues—staff and fellows—by observing their cases, or discussing research at conferences.

How has COVID-19 impacted your neurointerventional practice?

COVID-19 has impacted every single aspect of our lives including, therefore, our clinical practice. The direct and most obvious effects on neurointervention were increased door-to-puncture times in acute stroke due to personal protective equipment (PPE) requirements worn by the team, and delays in treatment for acute subarachnoid haemorrhage (SAH) as these patients require, at least in our hospital, a COVID-19 test.

We decreased our elective procedures to not overwhelm the intensive care unit (ICU) and wards. Interestingly, we also experienced a drop in both acute subarachnoid hemorrhage (SAH) and stroke patients and are wondering whether this is related to side-effects of confinement and the “stay at home—stay away from hospitals” notion that is prevalent in Canada. However, the effects of COVID-19 go beyond the clinical realm: we feel the impact on teaching, with no in-person meetings, no observerships, and no “hands-on” courses that we previously held for flow diversion or stroke at our institution.

We had to cancel our annual interventional neuroradiology meeting, for the first time in the past 20 years, and will hold our Canadian Course of Diagnostic Neuroradiology virtually instead of in person. Many research studies were put on hold, including recruitment in multicentre stroke trials.

What are the biggest learnings you would like to share with the wider neuro community about your department’s response to COVID-19?

The most profound and scaring changes I felt are the impact of increased levels of anxiety and stress on the team. Neurointerventionalists are accustomed to stress in the form of working long hours at high stakes, however, this stress comes with job satisfaction. The stress and anxiety levels imposed on us because of COVID-19 are different, and we should not underestimate the risk of burnout. As such, my biggest learnings from COVID-19 are that we need to take better care of each other and ourselves, be supportive of members of the team and rely on social networks.

What has been the most important development in the neurointerventional field during your career?

The knee-jerk answer to this question for anyone who has lived through the intra-arterial tPA and/or urokinase era is of course stroke thrombectomy using stentretriever or aspiration. It is only 10 years ago that we waited for what felt like hours to infuse the tPA, just to realise the futility of our treatment in a large proportion of cases. In its current state, with success rates at more than 80% and procedural times rarely exceeding 40 minutes, stroke treatment certainly has been one of the most impactful developments in neurointervention.

In addition, I believe that the development of large inner diameter distal access catheters has not only enabled stroke thrombectomy, but has changed our ability to treat more and more complex neurovascular diseases with an ever-increasing armamentarium of devices.

These distal access devices have been instrumental, not only for stroke treatment, but have opened the door to safe and accurate deployment of flowdiverters, intrasaccular aneurysm devices, and safer multicatheter approaches for aneurysms or arteriovenous malformations, which we now see as routine procedures.

What has been the biggest disappointment?

The low point of intraarterial stroke treatment was the 2013 International Stroke Conference (ISC) in Hawaii, USA, where three consecutive intravenous versus intra-arterial stroke trials demonstrated inferiority of intra-arterial stroke treatments. If it had not been for the comeback victory for mechanical thrombectomy in stroke just two years later at the ISC in Nashville, USA, with three overwhelmingly positive trials, stroke patients worldwide would have lost an excellent treatment for their condition. This shows that being in the driver’s seat when it comes to trial design is important.

What technological advances do you see shaping neuroradiology treatment over the next 10 years, or beyond?

Technological advances will be driven by the demand imposed by the treatment of neurovascular diseases. Thus, artificial intelligence tools to improve stroke workflow or robotics to provide remote care will likely become an ever-prevalent reality in the near future. Beyond this, future neurointerventional care will likely necessitate appropriateness criteria for treatment as well as personalised medicine and quality control. As such, advanced neuroimaging for patient selection, integration of individual health data in treatment plansand collection of big data in common databases will play a significant role in our day-to-day lives. With the identification of somatic mutations in brain vascular malformations and molecular pathways in vascular disease progression, we will move more towards targeted drug treatment approaches rather than looking only at new mechanical devices.

What are your current research interests?

In my current role, I see myself foremost as a facilitator of the excellent work of my colleagues at the Toronto Western Hospital. We are focusing, in collaboration with our colleagues in neurology and neurosurgery, on the prediction of brain bleeding from brain vascular malformations, using a multidiscplinary approach, development of novel methods to treat these lifechanging events and estimating the relative effectiveness of treatments to determine their impact on healthcare.

Do you have a fantasy experiment?

I would like to continue recent preliminary work that we performed on evaluating whether intravascular devices (so-called stentrodes) implanted into the vascular system could be used for non-invasive brain stimulation. With current catheter technology it is possible to non-invasively navigate into very distal vessels and we have recently mapped the relationship between vascular structures and potential brain stimulation targets. I think it would be amazing to one day integrate neuromodulation and neurointervention.

What are your interests outside of medicine?

I like to spend time with my family. I have two young girls aged eight and 10. We spend the winters skiing, while in the summers we like hiking or other outdoor activities, like canoeing and swimming—the latter I used to do competitively when younger.

Recently, I was ‘forced’ by my kids to enrol with them in a family production of the musical Wicked, although singing is really not my forte. I enjoy traveling, in particular to Europe and Asia. I appreciate watching and listening to ballet and opera, with Swan Lake and Madama Butterfly being my respective favourites, and I admire Chinese art, especially calligraphy.


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