Validation of Cardiac Magnetic Resonance Sequences in Patients With Single Ventricles

Summary

Single ventricle defects make up the severe end of the congenital heart disease spectrum. The Fontan operation leads to a complete redirection of systemic venous blood outside of the heart and directly into the lungs. Patients with single ventricles suffer from multiple complications. Their survival has improved over the past decades, but is still severely compromised compared to the general population.

Their evaluation includes echocardiography and functional status by history and/or exercise testing. In longer intervals or if echocardiography does not allow visualization of all cardiovascular structures, cardiac magnetic resonance (CMR) is employed. Many patients also undergo more invasive cardiac catheterization.

In single ventricle patients, cardiac imaging has to address the questions of the patency of the Fontan pathways, i.e. all systemic veins, the Fontan conduit, and the pulmonary arteries, and of the function of the single ventricle (including myocardial function and valve function).

By using conventional imaging methods in Fontan patients, Ghelani et al. identified a CMR-based ventricular end-diastolic volume of \> 125 ml/m2 and an echocardiographic global circumferential strain (GCS) value of higher than -17% to be strong predictors for a combined adverse outcome of death or heart transplantation. While interobserver reproducibility of single ventricle ejection fraction is similarly high by echocardiography, CMR is better in reliably measuring ventricular mass and diastolic volume and can provide additional information by MR feature tracking (strain), T1 mapping, and 4D flow measurements. Several substances that can be measured in the peripheral blood are being increasingly investigated as biomarkers of heart failure.

In conclusion, several advanced CMR sequences and new biomarkers have a potential role in the assessment and risk stratification of single ventricle patients. Every single published study has elucidated a particular use and aspect of these parameters, but broader correlations and prognostic values are still unclear.

The investigators hypothesize that myocardial strain (by feature tracking), myocardial fibrosis (by T1 mapping), and intracardiac flow disturbances (by 4D flow) along with biomarkers are diagnostic for single ventricle dysfunction and correlate with known prognostic factors.

This is a single center, prospective, observational cohort study. There will be no randomisation or blinding. Study setting: outpatients, cardiology clinic and radiology department, academic hospital. Every patient will be examined twice with a one-year interval (MR will only be repeated if clinically indicated).

Conditions

• Single-ventricle

Interventions

DIAGNOSTIC_TEST

Cardiac Magnetic Resonance Imaging

Cardiac Magnetic Resonance Imaging (non-invasive, with i.v. application of contrast), awake or (if clinically indicated) in general anesthesia

DIAGNOSTIC_TEST

Blood draw for hematocrit and heart failure biomarkers

Approximately 10 ml of blood will be drawn before administration of contrast medium.

DIAGNOSTIC_TEST

Cardiopulmonary exercise test

In patients 8 years of age or older: on a cycle ergometer with breath-by-breath analysis, continuous ECG and SpO2 monitoring during exercise, after a baseline spirometry and bodyplethysmography

DIAGNOSTIC_TEST

Exhalomics

Measurement of exhaled molecules by mass spectrometry; patients breathe into a mouthpiece for 15 seconds 6 times (total time requirement: about 5 minutes)

DIAGNOSTIC_TEST

Quality of life questionnaire

Questionnaire to be filled out by the Patient regarding quality of life perception

Sponsors & Collaborators

• Barbara Burkhardt

  lead OTHER

Principal Investigators

• Barbara EU Burkhardt, MD · University of Zurich Children's Hospital

Eligibility

Sex

ALL

Healthy Volunteers

No

Timeline & Regulatory

Start

2019-09-01

Primary Completion

2023-08-31

Completion

2023-08-31

Countries

• Switzerland

Study Locations