U.K. Boy First in World to Have MRI-Guided Heart Valve Op

A six-year-old boy from Central England has become the first person in the world to have an operation to widen a heart valve that was guided by MRI scanning rather than by X-rays.

The BBC explains that six-year-old Jack Walborn from Alford, Lincolnshire was born with pulmonary valve stenosis, a condition which was reducing blood flow to Jack's lungs because a valve in the right side of his heart was narrower than it should be. An operation known as a valvuloplasty was going to be required to widen the valve in Jack's heart, the Telegraph says that left untreated the narrow valve may have threatened the young boy's life, and increase the flow of blood. The Press Association describes how a valvuloplasty involves inserting a cardiac catheter into a blood vessel in the arm or groin of a patient, then guiding it through the patient's body to their heart, where a balloon at the tip of the catheter is carefully inflated to widen the narrower-than-normal heart valve. Tens of thousands of patients in the U.K. each year undergo procedures where X-ray guided wires and instruments pass through blood vessels and the procedures are considered preferable to opening up a patient's chest or abdomen to operate as they can be performed in a shorter period of time and are less complicated. However the one drawback to those procedures has been the use of X-ray imaging to monitor catheters as they move through the body, exposing patients to radiation that can in a small number of cases lead to cancer later in life. And Reza Razavi, a professor of imaging science and a consultant paediatric cardiologist who performed the operation on Jack shortly before Christmas, at Kings College Hospital in London, has spoken of the particular danger from radiation faced by children, saying:

Avoiding radiation is especially important in children whose cells are more prone to radiation damage and the risks of cancer are higher but it is important for everyone, adult patients and even the doctors and nurses in the room during the procedure. The risk of cancer from x-rays is very small for the individual but because so many procedures are done, the benefits across the population are substantial

To address the problems associated with X-rays and radiation a team from King's Health Partners Academic Health Sciences Centre in London developed a technique whereby MRI scanning rather than X-ray imaging monitors the progress of a catheter that is inserted into a patient's body. Apart from avoiding the potential problems to which the use of X-rays might lead MRI gives clearer, more detailed images from within a person's body. But there were difficulties too with using MRI for such as a valvuloplasty, those difficulties being to do with the metal guide wires employed in the relevant procedures. Clinical research fellow at King's College London, Dr Aphrodite Tzifa, spoke of how the difficulties with the guide wires were overcome. She said:

We were faced with a problem because an MRI scanner uses a powerful magnetic field to construct images of the body. This magnetism not only caused the guide wire to move around inside the body, but also resulted in the tip of the wire heating up to temperatures of up to 70ºC. We have been working for the last three years to develop a new guide wire that can be used with MRI and have come up with a fibreglass wire that has small iron markers along it that can be seen on the scan

With the new technique and device approved by King’s College Hospital Research Ethics Committee and the Medicines and Healthcare products Regulatory Agency (MHRA) respectively, within the next five years thousands more NHS patients should be treated in a similar way to Jack Walborn, whose mother Kerry Walborn told the media:

At first I was unsure about allowing Jack to be the first person to have this operation, but once I had spoken to the doctors I felt much more at ease as I knew he was in safe hands. His surgery was a great success and within an hour of coming out of theatre he was running around and back to being his lively self. He has had colds than have affected him more than this surgery. It was just brilliant and I am so glad we went through with it