Early postoperative remodelling following repair of tetralogy of Fallot utilising unsedated cardiac magnetic resonance: a pilot study

Abstract

Introduction The right ventricular adaptations early after surgery in infants with tetralogy of Fallot are important to understand the changes that occur later on in life; this physiology has not been fully delineated. We sought to assess early post-operative right ventricular remodeling in patients with tetralogy of Fallot by cardiac magnetic resonance imaging. Materials and Method Subjects with tetralogy of Fallot under 1 year of age were recruited following complete surgical repair for tetralogy of Fallot. Protocol-based cardiac magnetic resonance imaging to assess anatomy, function, and flows was performed before hospital discharge using the Feed and Sleep technique, an unsedated imaging technique. Results Magnetic resonance imaging was completed in 16 subjects at a median age of 77 days (Interquartile range 114). There was normal ventricular ejection fraction and indexed right ventricular end-diastolic volume (48 ± 13 cc/m2), but elevated right ventricular mass (Z-score 6.2 ± 2.4). Subjects requiring a transannular patch or right ventricle to pulmonary artery conduit had moderate pulmonary insufficiency (Regurgitant fraction 27 ± 16. Discussion Early right ventricular remodeling after surgical repair for tetralogy of Fallot is characterized by significant pulmonary regurgitation, right ventricular hypertrophy, and lack of dilation. Performing cardiac magnetic resonance imaging using the Feed and Sleep technique is feasible in infants younger than five months. These results might open new avenues to study longitudinal right ventricular changes in tetralogy of Fallot and to further explore the utility of unsedated magnetic resonance imaging in patients with other types of congenial heart defects.

Changes in Right Ventricular Volume, Volume Load, and Function Measured with Cardiac Computed Tomography over the Entire Time Course of Tetralogy of Fallot

“…These discrepant results may be resolved by future studies. It is noteworthy that 24% of cardiac MRI examinations failed in a previous study (29), but no cardiac CT examinations failed in the present study.…”

“…This may be explained not only as a normalization process from TOF hemodynamics (represented as a small heart) after total surgical repair, but also as a consequence of PR, myocardial injury during relief of RVOT obstruction, and insertion of noncontractile materials. In a study using cardiac MRI with the feed-and-sleep technique (29), the RV and LV volumes and functions in 16 infants (≤ 1 year of age) who underwent total surgical repair showed normal values. In contrast, the results of the 16 infants ≤ 1 year of age in this study demonstrated slightly higher ventricular volumes and slightly lower RV EF than the published normal values (at the comparable BSA of 0.4) that were measured using cardiac MRI (30).…”

Right Ventricular Strain Is Associated With Increased Length of Stay After Tetralogy of Fallot Repair

“…We have previously demonstrated that CMR is feasible in infants after TOF repair without sedation or anesthesia and found elevated RV mass and significant pulmonary regurgitation at this early stage. 14) However, RV strain by CMR has not been previously reported in this population immediately after TOF repair. Given the lack of knowledge on early RV remodeling, and its impact on outcomes, we sought to describe RV strain adaptation to TOF repair using CMR tissue tracking prior to hospital discharge from admission for the TOF repair.…”

“…The CMR was performed without sedation or anesthesia using the “feed and swaddle” technique and therefore performed without intravenous access or gadolinium. 14) 15) 16) This study was approved by the Institutional Review Board and informed consent was obtained for all patients.…”

Acute Change in Ventricular Contractility-Load Coupling After Corrective Surgery for Congenital Heart Defect: A Retrospective Cohort Study

“…We found that the change in VAC could not predict post-operative outcomes after the repair of TOF. Because pulmonary stenosis burdens the right ventricle rather than the left ventricle, right ventricular dysfunction has generally been targeted for management after surgery for TOF [21, 22]. Clinical implications of late post-operative cardiac derangement in TOF have also been focused on the right ventricle-pulmonary artery relationship [23].…”