“Our pioneering work is bearing fruit,” says cardiologist Marco Götte. “Being able apply innovative MRI technology during interventions opens the way to more precise, faster, safer and radiation-free treatment.” For example: the treatment of more complex cardiac arrhythmias, the placement of pacemakers or advanced cardio-diagnostics.
Cardiologist Marco Götte and electrophysiologist-cardiologist Cor Allaart both played a pioneering role in the realisation of the interventional cardiac MRI (iCMR) within the walls of Amsterdam UMC. It was never self-evident that simple cardiac arrhythmias could be treated while lying in an MRI scanner. Nevertheless, ten years ago Götte realised that the treatment of cardiac disorders could be significantly improved by combining the intervention with the imaging technology offered by an MRI scanner.
“With the help of MRI, you have a better view of the anatomy of the heart, but also of its dynamics. You see the entire heart, you see the structures, such as the blood vessels and the valves, and how they relate to each other. Navigating to the piece of tissue that needs to be treated is more precise. In principle, you can also immediately assess the texture of the tissue and changes in texture as a result of the procedure. X-ray techniques, which are still the standard, simply do not have these properties,” says Allaart.
Working in the dark
“The non-obviousness was not so much in the improbability of the idea as in its realisation,” adds Götte. “Cardiac arrhythmias are treated by scarring the heart muscle tissue to block the electrical impulses that cause the disorder. In the conventional manner, this so-called ablation treatment takes place with the aid of catheters, which are guided through the groin to the heart under x-ray guidance. It is a tried and tested method, but one of its major drawbacks is that you work in the dark, so to speak; during the procedure you cannot see exactly what you are changing in the heart tissue. Because you cannot immediately assess the ablated heart tissue, you only know afterwards whether the treatment has been successful. In more complex cardiac arrhythmias, this can be fatal."
The iCMR changes this. As noted above by Allaart, it provides the operating cardiologist with real-time feedback during the operation. Something that does not only have an impact for the success of the operation but also the long-term care of the patient.
Operating under the traditional way "can also have consequences for simple cardiac arrhythmias,” continues Götte, "we regularly have to repeat an ablation that initially seemed successful. Apart from extra exposure to X-rays, extra costs and capacity problems, this is particularly stressful for the patient. So, the idea of having applications of MRI imaging technology and intervention take place at the same time, so that you work with the light on, as it were, was immediately judged to be a more viable alternative than the current X-ray procedure."
However immediate this judgement may have been, it was only the beginning of the challenge. MRI was developed as an imaging technique and not as a place for surgical interventions. From which catheters were allowed in the MRI (metal is a no, no in the MRI-room) to how to scar the heart muscle and ensure these scares remained visible, everything had to be rethought. "Those involved in the world of electrophysiology and MRI technology not only had to be convinced that a combined approach would lead to better results, but they also had to become proficient and learn to speak each other's language," notes Götte
"That is not to mention the financial investments we had to make, building a new multidisciplinary team, redesigning procedures and working methods, and implementing new standards in order to comply with existing laws and regulations. Even though at that time there was no scientific evidence that cardiac arrhythmias could be treated more accurately, faster, safer and cheaper in this way. But we can now largely put all this behind us. The method has now been implemented and we routinely perform it in the treatment of simple cardiac arrhythmias. With our multidisciplinary team, we are now on the eve of applying this intervention to more complex treatments. If that promise is fulfilled, then that will indeed be ground-breaking,” he concludes.
New location
Amsterdam UMC is currently busy with the construction of its new Heart Center, something that will also facilitate more iCMR innovations. "An important precondition for further proficiency in innovative MRI technology,” says Allaart, “is the planned realisation of seven cardiac catheterisation rooms in the newly built Heart Center, one of which will be equipped with a state-of-the-art interventional MRI scanner. Only then can we take the really big steps. Until then, we will work from an existing, conventional MRI scanner near the cardiac catheterisation room and develop what is responsible in this setting."
However, although construction expected is to last until 2025, the team still expect short-term advances in the work that can be done in the iCMR. "By the end of this year, we want to be able to treat complex arrhythmias in the ventricle. We are currently working hard on the realisation of technical preconditions for this. For example, we are still testing an MRI-compatible ECG system, with which we can make continuous heart films from the scanner. We are also still awaiting a defibrillator that we can use in the vicinity of the MRI scanner which we'd need if the patient unexpectedly develops a dangerous arrhythmia during treatment,” continues Allaart.
Further, the team are looking to expand the diagnostic capabilities of the iCMR. "For example, we can now measure blood pressure in the MRI at various places in the heart and lungs. This combination of blood pressure measurement and imaging yields more than the sum of its parts, you collect extra information that can be decisive for the treatment. What we also see as a priority is to take more accurate heart biopsies with the help of iCMR, so that the chance of 'mishaps' becomes nil," adds Allaart.
However, as with all other iCMR innovations, this requires a trip back to the drawing board. Currently special iCMR bioptomes, small tweezer-like instruments, are currently being developed, that can be used to obtain a small piece of heart muscle tissue for further examination.
Allaart also has plans for after the construction of the new Heart Center: "The provisional last step that we now envisage as a future application is the injection of stem cells into the heart using iCMR, for example in the treatment of heart failure and congenital heart defects. It is an innovative treatment that we are conducting promising research into at the Heart Center and that is followed with interest worldwide. This also requires a special catheter that must meet all requirements for use in an iCMR environment. Unfortunately, we can really only apply this technique after the construction of the new Heart Center."
Dot on the horizon
While there is still plenty of work to be done, the dot on the horizon is crystal clear for both. “With MRI-guided treatment of heart conditions, we are working towards fewer procedures per patient, fewer hospital admissions and less medication. Ultimately, of course, the point is that patients benefit from these advanced treatments. Once we have proven that our approach is more effective than existing therapies, it's our task to also help other centers implement components that are relevant to them. Perhaps MRI-guided treatment of heart disease will then even become the norm and replace X-ray-driven treatments,” concludes Götte.
