Impact of Right Ventricular Pressure Load After Repair of Tetralogy of Fallot

Assessment of Pulmonary Arterial Vascular Impedance in Fetuses With Tetralogy of Fallot

OBJECTIVE

To evaluate the vascular impedance of the pulmonary arteries in fetuses with tetralogy of Fallot (TOF) by Doppler echocardiography.

METHODS

A total of 42 fetuses with TOF (TOF group) and 84 gestational age-matched normal fetuses (control group) were prospectively collected from the Second Xiangya Hospital of Central South University from August 2022 to January 2023. The severity of TOF was classified into mild TOF (z score ≥-2), moderate TOF (-4 < z score < -2), or severe TOF (z score ≤-4) according to the z score value of the pulmonary annulus diameter. The pulsatility index (PI) of the main pulmonary artery (MPA), distal left pulmonary artery (DLPA), and distal right pulmonary artery (DRPA) were measured by pulsed-wave Doppler. The differences in clinical data and echocardiographic parameters between TOF group, control group, and TOF subgroups were compared.

RESULTS

Compared with the control group, MPA-PI increased significantly, whereas DLPA-PI and DRPA-PI decreased in TOF group (all P < .001). There were no significant differences in MPA-PI and DRPA-PI among mild TOF, moderate TOF, and severe TOF (all P > .05). However, DLPA-PI decreased significantly in severe TOF compared with mild TOF (P < .05).

CONCLUSION

Fetuses with TOF presented increased vascular impedance in the pulmonary trunk and decreased impedance in distal pulmonary artery branches. Further large and follow-up studies are needed to demonstrate the associations between those changed vascular impedances and the development of PA in patients with TOF.

Clinical impact of novel CMR technology on patients with congenital heart disease. A scientific statement of the Association for European Pediatric and Congenital Cardiology (AEPC) and the European Association of Cardiovascular Imaging (EACVI) of the ESC

Cardiovascular magnetic resonance (CMR) imaging is recommended in patients with congenital heart disease (CHD) in clinical practice guidelines as the imaging standard for a large variety of diseases. As CMR is evolving, novel techniques are becoming available. Some of them are already used clinically, whereas others still need further evaluation. In this statement the authors give an overview of relevant new CMR techniques for the assessment of CHD. Studies with reference values for these new techniques are listed in the supplement.

Current status of transcatheter intervention for complex right ventricular outflow tract abnormalities

Various transcatheter interventions for the right ventricular outflow tract (RVOT) have been introduced and developed in recent decades. Transcatheter pulmonary valve perforation was first introduced in the 1990s. Radiofrequency wire perforation has been the approach of choice for membranous pulmonary atresia in newborns, with high success rates, although complication rates remain relatively common. Stenting of the RVOT is a novel palliative treatment that may improve hemodynamics in neonatal patients with reduced pulmonary blood flow and RVOT obstruction. Whether this option is superior to other surgical palliative strategies or early primary repair of tetralogy of Fallot remains unclear. Transcatheter pulmonary valve replacement has been one of the biggest innovations in the last two decades. With the success of the Melody and SAPIEN valves, this technique has evolved into the gold standard therapy for RVOT abnormalities with excellent procedural safety and efficacy. Challenges remain in managing the wide heterogeneity of postoperative lesions seen in RVOT, and various technical modifications, such as pre-stenting, valve ring modification, or development of self-expanding systems, have been made. Recent large studies have revealed outcomes comparable to those of surgery, with less morbidity. Further experience and multicenter studies and registries to compare the outcomes of various strategies are necessary, with the ultimate goal of a single-step, minimally invasive approach offering the best longer-term anatomical and physiological results.

Right ventricular to pulmonary arterial coupling in patients with repaired tetralogy of Fallot: a case series

Background

In repaired tetralogy of Fallot (ToF) patients with residual right ventricular (RV) outflow tract obstructions (RVOTO), risk stratification and timing of re-interventions are based on RVOTO gradients. However, this might be insufficient to prevent RV dysfunction. Instead, assessment of RV to pulmonary arterial (RV-PA) coupling allows integrated assessment of RV function in relationship to its afterload and could be of additional value in clinical decision-making.

Case summary

Two patients with repaired ToF and residual RVOTO without pulmonary regurgitation underwent right heart catheterization (RHC) and cardiac magnetic resonance imaging. We determined RV end-systolic elastance (Ees), arterial elastance (Ea) and RV-PA coupling (Ees/Ea) using single-beat RV pressure-volume analysis. Patient 1 was asymptomatic despite severely increased RV pressures and a left pulmonary artery (LPA) stenosis (invasive gradient 20 mmHg). Right ventricular volumes and function were preserved. The Ea and Ees were increased but RV-PA coupling was relatively maintained. Of interest, RV end-diastolic pressure and RV diastolic stiffness were increased. After LPA plasty, RV function was preserved during long-term follow-up. Patient 2 was symptomatic despite mildly elevated RV pressures and a supravalvular RV-PA conduit stenosis (invasive gradient 30 mmHg). The RV showed severe RV dilatation and dysfunction. The Ea was increased but Ees was decreased leading to RV-PA uncoupling. Despite balloon angioplasty, RV function was unchanged during long-term follow-up.

Discussion

Development of RV dysfunction might be insufficiently predicted by RVOTO severity in patients with repaired ToF. Assessment of RV remodelling and function in relationship to its afterload might help to optimize risk stratification.

Treatment of Severe Pulmonary Regurgitation in Enlarged Native Right Ventricular Outflow Tracts: Transcatheter Pulmonary Valve Replacement with Three-Dimensional Printing Guidance

BACKGROUND

Severe pulmonary regurgitation (PR) often occurs following a transannular patch repair of tetralogy of Fallot, resulting in an enlarged native right ventricular outflow tract (nRVOT) with varying shapes.

METHODS

We conducted a single-center study with eight patients having severe PR and enlarged nRVOT (diameters ≥ 29 mm). Transcatheter pulmonary valve replacement (TPVR) was performed using the self-expanding PT-Valve. Preoperative evaluation included echocardiography, computed tomography, and magnetic resonance imaging. A 3D-printed model of the nRVOT was used for preoperative assessment. Follow-up data were collected in 1-year follow-up.

RESULTS

PT-Valve was successfully implanted in all patients, resulting in immediate improvement of severe PR. Pulmonary artery diastolic pressure increased significantly (p < 0.001). No deaths or coronary compression occurred during the procedure. Over a 1-year follow-up, no stent displacement or fracture occurred. Only two patients had trace paravalvular leaks. Magnetic resonance imaging revealed a reversal of right ventricular remodeling, with a significant reduction in right ventricular end-diastolic volume index (p < 0.001) and improved right ventricular ejection fraction (p < 0.001). All patients achieved primary endpoints.

CONCLUSION

3D printing-guided PT-Valve implantation in enlarged nRVOT for severe PR is safe and effective, expanding TPVR indications and offering potential treatment for a broader patient population.

Exercise in patients with repaired tetralogy of Fallot: a systematic review and meta-analysis

OBJECTIVE

Children and adults with repaired tetralogy of Fallot (rTOF) have an impaired exercise capacity, a less active lifestyle and an increased long-term risk of adverse outcomes compared with healthy peers. This study aimed to summarise the current evidence for the effectiveness and safety of exercise training interventions in patients with rTOF.

METHODS

PubMed/MEDLINE, EMBASE, the Cochrane Central Register of Controlled Trials (CENTRAL), Web of Science, Scopus and reference lists of relevant articles were searched for prospective studies published by November 2021. Random-effects meta-analysis and descriptive synthesis were performed to assess the effectiveness and safety of exercise training in patients with rTOF.

RESULTS

Of the 9677 citations identified, 12 articles were included that reported on 10 unique studies and covered 208 patients with rTOF (range of mean/median age: 7.4-43.3 years). All studies implemented 2 to 7 aerobic or respiratory training sessions per week with durations ranging from 6 to 26 weeks. Meta-analysis of the included randomised controlled trials showed that exercise training was associated with a significant improvement in peak VO₂ (pooled mean difference: +3.1 mL/min/kg; 95% CI: 0.76 to 5.36 mL/min/kg, p=0.019). Cardiac imaging studies revealed no subclinical adverse remodelling after the exercise interventions. No serious adverse events including arrhythmias were reported in these studies.

CONCLUSION

Current evidence suggests that exercise training can improve exercise capacity in patients with rTOF with a low risk for adverse events. Exercise prescription may be a safe and effective tool to help improving outcomes in patients with rTOF.

PROSPERO REGISTRATION NUMBER

CRD42021292809.

Preserving the pulmonary valve in Tetralogy of Fallot repair: Reconsidering the indication for valve-sparing

BACKGROUND

Tetralogy of Fallot (TOF) repair is a frequent procedure, and although valve-sparing (VS) repair is preferred, determining which patients can successfully undergo this operation remains controversial. We sought to identify parameters to determine a selective, accurate indication for VS repair.

METHODS

We reviewed 71 patients (82%) undergoing VS repair. We analyzed hemodynamic data, intraoperative reports, and follow-up echocardiography results to identify acceptable indications. Patients requiring pulmonary valve (PV) reintervention versus no reintervention were compared.

RESULTS

PV annulus size at repair was z-score of -2.0 (-5.3, 1.3). Approximately half (51%) had a z-score less than -2. Cox regression results showed this was not a risk factor for reintervention (p = .59). Overall, 1-, 3-, 5-, and 10-year freedom from PV reintervention rates were 95.8%, 92.8%, 91% and 77.8%, respectively. Residual pulmonary stenosis (PS) at initial repair was relatively higher in the reintervention group compared with no reintervention group (40 [28, 51] mmHg vs. 30 [22, 37] mmHg; p = .08). For patients with residual PS, pressure gradient (PG) was consistent over time across both groups (PV reintervention: -3 [-15, 8] mmHg vs. no reintervention: 0 [-9, 8] mmHg). The risk of PV reintervention is 3.7-fold higher when the PG from intraoperative TEE is greater than 45 mmHg (p = .04).

CONCLUSIONS

Our review of the midterm outcomes of expanded indication for VS suggests intraoperative decision to convert to transannular patch is warranted if intraoperative postprocedure TEE PG is greater than 45 mmHg or RV pressure is higher than half of systemic pressure to prevent reintervention.