At the German heart institute in Berlin, clinicians face many situations in clinical everyday practice in which the decision-making process is not always straightforward. This is the case of a six years old boy, who we had in cure, with a combined disease of bicuspid aortic valve and coarctation of the aorta. He came to us after having undergone already two balloon angioplasties in the past. He wasn’t taking medication and presented arterial hypertension. When measuring his blood pressure around both arms and both legs we found a gradient of 11mmHg, and by ECG examination we found a gradient of 43 mmHg: these are very high values compared to normal blood pressure values In the MRI scans we detected that there were two situations wherethe narrowing of the aorta took place.That circumstance put us in front of two choices: place a stent or not in these two locations? Where to exactly place it?
Taking a closer look atthe existing evidence
Accounting for 5-8% of all congenital heart defects, coarctation of the aorta is associated with increased morbidity and mortality even years after treatment. Percutaneous catheter interventions are attractive treatment alternatives to surgical repair in patients with suitable anatomy and include balloon dilatation and stenting. As part of the FP7-funded CARDIOPROOF project, researchers Maximilian Salcher and Huseyin Naci of the London School of Economics and Political Science (LSE) led a recent systematic review and meta-analysis of clinical studies to assess whether one of these intervention strategies leads to better results. Both researchers are based at LSE Health, one of the largest research centres of the LSE.
Within CARDIOPROOF Siemens is interested in validating coupled computational models of blood flow and wall deformation for assessing the role of haemodynamics, wall mechanics and anatomy in dilatation of ascending aorta. Aortic arch dilatation occurs frequently and at a young age in patients with aortic disease, such as aortic valve disease (AVD) and aortic coarctation (CoA) specifically addressed in the project. Moreover, independently of the type of aortic disease, aortic dilation is a significant predictor of dissection and rupture (acute cardiovascular events leading to death if untreated), thus evolution of aortic arch dilation is important for prognostics.
Background and motivation
CARDIOPROOF focuses on patients with aortic valve disease (AVD) and coarctation of the aorta (CoA), disorders that are characterized by LV pressure and/or volume overload. Such overload induces a complex cascade of myocardial and vascular wall remodelling (eccentric/concentric hypertrophy, myocardial fibrosis, etc.), which if left untreated can progress to heart failure. In severe cases of AVD and CoA, treatment is necessary, however the optimum timing and the best type of treatment are difficult to determine. Guidelines of the European Society of Cardiology (ESC) and Association for Paediatric and Congenital Cardiology (AEPC) are complex and rely mostly on gross parameters from echocardiographic measurements (global ventricular pump function), arterial blood pressures and clinical symptoms.
A potentially powerful approach to improve diagnosis, patient selection and therapy delivery is the use of patient-specific computational models, which are built using data routinely recorded in the clinic.