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Between five and eight percent of all children born with congenitally malformed hearts suffer from coarctations
of the aorta. Some severe coarctations can only be treated by surgical repair. Untreated, this defect can cause
serious damage to organ development or even lead to death. Patch repair requires open surgery. It can affect
patients of any age: newborns with severe coarctation and/or hypoplastic aortic arch as well as older patients with
late diagnosis of coarctation of the aorta. Another patient group are patients of varying age with re-coarctation
of the aorta or hypoplastic aortic arch after surgical and/or interventional repair. If anatomy is complex and
interventional treatment by catheterization, balloon angioplasty or stent placement is not possible, surgery is
indicated.
The choice of type of surgery depends not only on the given anatomy but also on the experience the surgical
team has with each method. One surgical approach is patch repair. A patch of a suitable shape and size is sewed
into the aorta to expand the aortic lumen at the site of coarctation. At present, the shape and size of the patch
are estimated intra-operatively by the surgeon.
We have developed a software application that allows planning of the patch pre-operatively on the basis of
magnetic resonance angiographic data. The application determines the diameter of the coarctation and/or
hypoplastic segment and constructs a patch proposal by calculating the difference to the normal vessel diameter
pre-operatively. Evaluation of MR angiographic datasets from 12 test patients with different kinds of aortic
arch stenosis shows a divergence of only (1.5±1.2) mm in coarctation diameters between manual segmentations
and our approach, with comparable time expenditure. Following this proposal the patch can be prepared and
adapted to the patient's anatomy pre-operatively. Ideally, this leads to shorter operation times and a better
long-term outcome with a reduced rate of residual stenosis and re-stenosis and aneurysm formation.
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