Hemodynamic characterization of cardiac disease and aortopathy in congenital heart disease: a 4D flow MRI study

Study Background
Around 6 to 13 per 1000 of newborns are born with congenital heart disease
(CHD). CHD comprises a spectrum of different pathologies affecting the heart or
great vessels. These defects lead to abnormal flow patterns in the heart and
great vessels, leading to volume or pressure overload of heart compartments,
desaturation or energy loss. 4D flow MRI allows for evaluation of blood flow
characteristics patients with congenital heart disease.
This study is designed as a single centre, cross sectional study.
The following patients will be included in this study:

- Bicuspid aortic valve
- Coarctation of the aorta
- Fontan Circulation
- Aortic dilatation

Bicuspid aortic valve disease
40 patients will be prospectively signed up by their respective cardiologist
for an annual MRI scan in our tertiary clinic. In this single centre cross
sectional study, the patients will received a 4D flow analysis. Our analysis
will contain helical and vortex flow (grade 0-3), systolic flow eccentricity
(1-3 point scale), and segmental division of peak systolic wall shear stress
(WSSpeak) in the thoracic aorta and energy loss.

Coarctatio aortae
Forty patients who underwent surgical CoA rapaire (by either end-tot end
anastomosis, subclavian flap or tube interposition graft) will prospectively be
signed up by their respective cardiologist for a regular MRI scan in our
tertiary referral centre. In this single centre cross sectional study, patients
will received an additional 4D flow analysis. Our analysis will contain helical
and vortex flow (grade 0-3), systolic flow eccentricity (1-3 point scale), and
segmental division of peak systolic wall shear stress (WSSpeak) in the thoracic
aorta and energy loss. These findings will be related to the degree of aortic
dilataton, and the degree of hypertension (blood pressure and number of
antihypertensive drugs).


Fontan Circulation
20 Fontan patients will be prospectively signed up by their respective
cardiologist for a regular MRI scan in our tertiary clinic. In this single
centre cross-sectional study, patients will receive a 4D flow analysis. Our
analysis will contain helical and vortex flow (grade 0-3) and energy loss in
the TCPC and relate this to symptoms and exercise capacity. Second, we will
quantify the relationship between energy loss in the TCPC and the development
of veno-venous collaterals.

Aortic dilatation
Dilatation of the aortic root increases the risk of aortic complications, such
as aortic dissection, rupture and/or sudden death. Although the
pathophysiological process of progressive dilatation of the ascending aorta is
not fully understood, it is thought that this it is the result of genetic
predisposition and abnormal blood flow patterns caused by aortic valve
morphology. With the use of 4D-flow MRI, we can identify regions with abnormal
WSS and can provide a concise tool to investigate the pathological relationship
between WSS and aortic dilation. The relationship between aortic valve
function, aortic root diameters and 4D-flow MRI derived wall shear stress will
be examined.

Single centre, cross-sectional study.

risk and burden: none.
Benefits: understanding the abnormal haemodynamics and thus making a
potentially more efficient treatment plan..