Palliation Strategy to Achieve Complete Repair in Symptomatic Neonates with Tetralogy of Fallot.
Law MA, Glatz AC, Romano JC, Chai PJ, Mascio CE, Petit CJ, McCracken CE, Kelleman MS, Nicholson GT, Meadows JJ, Zampi JD, Shahanavaz S, Batlivala SP, Pettus J, Pajk AL, Hock KM, Goldstein BH, Qureshi AM; Congenital Cardiac Research Collaborative (CCRC) Investigators.Pediatr Cardiol. 2022 Oct;43(7):1587-1598. doi: 10.1007/s00246-022-02886-0. Epub 2022 Apr 5.PMID: 35381860
Commentary from Dr. Manoj Gupta (New York City, NY, USA), chief section editor of Pediatric & Fetal Cardiology Journal Watch.
Take home points:
- Neonates with symptomatic tetralogy of Fallot (sTOF) may undergo palliations with varying physiology, namely systemic to pulmonary artery connections (SPC) or right ventricular outflow tract interventions (RVOTI). A comparison of palliative strategies based on the physiology created is lacking.
- RVOTI had increased interstage reintervention (HR=2.15).
- This data supports patient and institution individualized approach to palliation of symptomatic TOF.
Introduction
Neonates with symptomatic tetralogy of Fallot (sTOF) have cyanosis requiring early complete repair (CR) or palliation to augment pulmonary blood flow. Various palliation options are used, including BTT shunt, Balloon pulmonary valvuloplasty, RVOT stenting, surgical transannular patch, RV-PA conduit without VSD closure, PDA stenting.
These palliations create physiologic differences including volume loading of the heart and pulmonary vasculature as well as short- and medium-term risks. Generally, RVOTI allows for pulsatile flow into the pulmonary arteries with maintained systemic diastolic pressure, thereby potentially mitigating the risk of altered abdominal visceral and coronary perfusion seen in patients with systemic aorta to pulmonary artery connections (SPC) due to continuous pulmonary blood flow throughout diastole. Furthermore, RVOT stenting has been associated with increased pulmonary artery growth compared to BTTS in the TOF population.
Materials and Methods
A multicenter, retrospective cohort study was performed including consecutive neonates (<=30 days) with sTOF who underwent palliation at nine centers of the CCRC between January 1, 2005, and November 30, 2017.
Patients with the following diagnosis were excluded: (1) non-confluent branch pulmonary arteries; (2) TOF with atrioventricular canal; (3) TOF with absent pulmonary valve syndrome; (4) TOF with major aortopulmonary collateral arteries who underwent (or intent for) unifocalization, or (5) double outlet RV.
Patients were categorized into two palliative groups prior to the complete repair (CR) based on the predominant physiology created by the first palliative procedure: (1) SPC including surgical aorta to pulmonary artery shunts or ductus arteriosus stent; or (2) RVOTI including balloon pulmonary valvuloplasty, RV to pulmonary artery conduit/transannular patch without VSD closure, and RVOT stent.
Outcomes
The primary outcome was defined as survival to CR by 18 months. Secondary outcomes included overall survival and dichotomous events including procedural/hospital complications and interstage reinterventions (RI), and continuous measures of risk exposure including hospital/ intensive care length of stay, mechanical ventilation duration, inotropic agents, cardiopulmonary bypass (CPB)/ cross-clamp/inhaled anesthetic agent times, and pulmonary artery growth from birth to CR.
Baseline demographics of patients undergoing palliation
- DiGeorge syndrome: Total patients 43 (13.44%), SPC was performed in 28 (11.11%) and RVOTI was performed in 15 (22.06%), p value 0.019
- Birthweight < 2.5 kg: Total 96, 68 (27%) underwent SPC, and 28 (41%) were taken for RVOTI, p value 0.023
- More patients with branch pulmonary artery stenosis (z score < 2), underwent RVOT intervention. P value 0.007
Results
Nine patients’ palliative physiology changed within 60 days following initial palliative intervention. Six patients who underwent an initial balloon pulmonary valvuloplasty required SPC (one ductus arteriosus stent and five BTTS) while three patients changed physiologic palliative strategies from a SPC to RVOTI (one ductus arteriosus stent and two BTTS underwent RVOT patch).
Incidence of Complete Repair by 18 Months
Under 3 months from IP, CR was more likely in the RVOTI group (HR=2.60; 95% CI=1.12–5.95, p=0.026). After 3 months, there was no difference in the hazard of repair.
Neonatal and Overall Exposures and Morbidity
Duration of inotropes, ventilation, and CPB times favored RVOTI during the IP, while inotrope duration, CPB and anesthesia time favored RVOTI in the cumulative (IP+CR). No difference was noted in-hospital mortality and complications between the two groups.
Reintervention
Interstage RI was noted to be more frequent in RVOTI. By 12 months, cumulative pre-repair RI was 39.7% in RVOTI patients compared to 24.8% in SPC patients (HR = 1.73, 95% CI=1.11–2.70, p=0.015, SPC reference), and after adjustment similar findings were noted (HR = 2.15 95%, CI = 1.36, 3.39, p = 0.001).
Discussion
The management of sTOF is quite variable, with significant institutional variation in the palliative strategies offered to these neonates. This data suggests that an individual treating center’s management strategy specific to individual patient characteristics could be equally effective. This study highlights an important secondary outcome that RI burden after RVOTI is common.
Morbidity burden overall is similar between the two strategies. Neonatal morbidities of ventilation time and inotrope use were lower in RVOTI. This decrease is likely driven by a higher frequency of catheterization-based strategy in RVOTI and surgery in SPC. When comparing ductus arteriosus stent to BTTS, intensive care unit length of stay and procedural complications were lower in the ductus arteriosus stent group. Similarly, Stumper et al., described lower length of stay and intensive care unit readmissions when comparing RVOT stent to BTTS. The potential early morbidity benefit comes at a cost of increased RI as seen in this study as well as other studies of catheter-based interventions of ductus arteriosus stent versus BTTS.
Conclusion
In conclusion, palliative strategy comparing RVOTI to SPC in neonates with sTOF yields similar incidence of CR by 18 months and similar overall survival. While patients with RVOTI have a higher RI burden after IP the overall morbidity burden is generally similar among patients undergoing palliation when grouped based on physiology. This data supports patient and institution individualized approach to palliation of sTOF.
