Challenge:
Clinicians at Great Ormond Street Hospital for Children wanted to identify the optimum blood-vessel-stent diameter that would repair one patient’s unique problems following failure of a previous implant.
Solution:
Researchers at University College London Institute of Cardiovascular Science used Dassault Systèmes’ SIMULIA Abaqus, in combination with patient image data, to create personalized, virtual models of the patient’s anatomy. The implantation of different sized stents was simulated to compare their effects on blood flow, pressure, and aneurysm coverage.
Benefits:
SIMULIA tools helped the engineers and clinicians collaborate on visualizing the challenge and selecting the stent diameter that was the most effective in treating the patient, resulting in a successful outcome.
The 19-year old patient was in trouble. Born with an initially undetected congenital malformation of the aorta, the major artery of the heart, he had a metal stent implanted at eight years of age to widen the blood vessel and restore normal flow. At first the treatment to correct his coarctation of the aorta (COA) was a success. But, despite re-dilation six years later, the supporting structure of the stent narrowed again, fracturing in places and allowing the aorta to form a small but potentially dangerous aneurysm (a bulge in the vessel wall that could burst).
Many types of congenital heart abnormalities can be corrected in very young babies through open-heart surgery. But sometimes such problems aren’t identified until a person is older. Even repairs made at birth can occasionally fail over time.
Balloon angioplasty—the insertion via catheter, of an inflatable balloon that widens the blood vessel—became an accepted (and much less invasive) corrective procedure in the 1980s for older children or adults. Starting in the 1990s, adding a stent into a balloon-widened artery (as was done with this patient when he was eight) proved to be an effective way to stave off further complications.
But doctors who were monitoring this patient’s condition realized by the time he was 18 that complications had, in fact, developed. An echocardiogram and examination through a catheter-guided system revealed that the COA had recurred and was now accompanied by a threatening aneurysm. A covered stent is usually placed to protect the aneurysm, but in this patient, another important artery bringing blood to the right arm was starting from the site of implantation and could not be risked. As the patient turned 19, the cardiologists began planning to replace the defective stent and repair the blood vessel wall in order to keep the young man healthy. But what would be the best route to success?
Simulation Helps Engineers and Clinicians Collaborate
Modern body-scanning technologies clearly show that no two people’s anatomies are alike. Fortunately, this individuality can now be translated into patient-specific computational modeling which is becoming a powerful, recognized tool to help clinicians plan complex interventions. Although not widely employed for treatment planning yet, use of such simulation methodology is starting to produce real-world results as engineers and physicians increasingly collaborate on patient cases.
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