Feasibility of Non-invasive Hemodynamic Assessment by 5D Flow in Congenital Heart Disease

Because of progress in early diagnosis, surgery, and medical treatment, almost all patients with congenital heart disease (CHD) survive nowadays into adulthood. However, most patients cannot be considered as cured as they are at high risk for complications like heart failure, valvopathies and pulmonary arterial hypertension (PAH). Treatment and diagnosis of these complications require often repetitive right-left heart catheterizations (RL-HC) for hemodynamic evaluations which are associated with a procedural risk, particularly in young patients in addition to a repeated radiation exposure. Advanced flow parameters obtained by the recently introduced Cardiac Magnetic Resonance (CMR) 4D flow technique promise non-invasive evaluation of hemodynamic parameters like pressure gradients and vascular resistance opening the door to partially replace RL-HC. However, 4D flow is limited by the need for ECG detection and cardiac movement during respiration. A new fully self-gated 5D CMR framework to cardiac and respiratory motion-resolved 3D flow imaging-5D flow aims to overcome these limitations. In addition, respiratory resolved flow determination is possible. As a result, 5D flow is a potentially powerful tool for the non-invasive assessment of hemodynamics like filling pressures and vascular resistance.

In the proposed study, patients will undergo a CMR-guided RL-HC in addition to a clinically indicated RL-HC.

As CMR is the gold standard for non-invasive flow determination, the combination of CMR-derived flow and RL-HC-derived pressures allows a precise evaluation of vascular resistance as it overcomes the limitations of the classic invasive methods for determination of cardiac output like the Fick or thermodilution techniques and the radiation exposure. This is particularly interesting in CHD patients in whom e.g. pulmonary resistance can differ in both lungs. For this reason, CMR guided heart catheterization (iCMR) is therefore increasingly incorporated in the routine use in different centers.

This study evaluates the feasibility of the determination of the relationship between noninvasive advanced 5D flow parameters and invasive catheter-derived vascular and ventricular hemodynamic parameters in PH/PAH and CHD patients. This will help to improve diagnosis and knowledge of the pathophysiological mechanisms in these complex patients.

All patients will undergo a clinical indicated standard RL-HC. In Fontan patients, a liver biopsy will be performed which is part of the routine follow-up for these patients. The participants are transferred to the interventional CMR suite. A RL-HC will be performed under CMR control. Invasive pressure measurements will be performed at predefined positions. After the RL-HC, the 5D flow will be obtained as well as a standard cardiac magnetic resonance imaging for determination of ventricular function and standard 2D and 4D flow.

Inclusion criteria

• Referral for work-up of known or suspected pulmonary hypertension (PH), RVOT pathology, or Fontan-type repair with a clinical indication for RL-HC.
• Ability to provide informed consent or have consent provided by a legal representative (and assent for minors aged 16-18).
• Male or female participants of all ethnicities and sociodemographic backgrounds

Exclusion criteria

• Participants unable to comply with study procedures due to language barriers, cognitive or psychological limitations, or lack of legal consent.
• Patients with contraindications to RL-HC or CMR.
• Patients not having a clinical indication to RL-HC.