Abstract
Background:
The optimal management of neonates with tetralogy of Fallot (TOF) and unfavorable anatomy remains debated. Early primary repair carries risks, while palliative options such as right ventricular outflow tract (RVOT) stenting have emerged as effective alternatives to conventional shunts. However, outcomes of corrective surgery following RVOT stenting remain underexplored.
Patients and Methods:
A retrospective study was done on 11 patients with TOF who underwent RVOT stenting followed by surgical repair between April 2021 and March 2025, from a total of 619 TOF surgeries. Data on demographics, intraoperative findings, pulmonary artery (PA) growth, and postoperative outcomes, including 30-day mortality, were collected. PA growth was assessed via z-scores pre- and poststenting. The correlation between time from stenting to surgery and operative duration was evaluated.
Results:
The median age and weight at surgery were 31 months and 10.2 kg, respectively. Complete stent excision was possible in 91% of patients. Transannular patch repair was required in 90.9% of cases. Prestent PA z-scores improved significantly by the time of surgery (left PA: −1.92 to –0.11; right PA: −2.95 to −0.46). Maximum PA growth occurred within 5 months poststenting. An increased interval between stenting and surgery correlated with prolonged cardiopulmonary bypass and aortic cross-clamp times. No in-hospital mortality or 30-day mortality occurred; the median ventilation was 12.7 h, and the mean intensive care unit stay was 2.1 days.
Conclusions:
Corrective surgery after RVOT stenting in TOF is safe and feasible, with favorable early outcomes. Early repair – preferably within 5 months of RVOT stenting – facilitates optimal PA growth and minimizes surgical complexity. Larger, prospective studies are warranted to standardize timing and assess long-term outcomes.
Keywords: Outcomes, right ventricular outflow tract stenting, surgery, tetralogy of Fallot
INTRODUCTION
The initial management of patients with tetralogy of Fallot (TOF), particularly those with unfavorable anatomy and reduced pulmonary blood flow, remains a topic of debate and a clinical challenge. Most patients with TOF achieve excellent outcomes following primary complete repair, typically performed between 3 and 9 months of age.[1] However, severely cyanotic neonates present a major clinical challenge, as early repair in this group continues to carry a high risk of mortality and the need for reintervention. Contributing risk factors include low body weight and hypoplastic or underdeveloped pulmonary arteries (PAs). Although palliative procedures offer improved survival prospects for high-risk neonates compared to early complete repair, the associated mortality remains considerable. Surgical systemic-to-PA shunts also pose their own challenges. Catheter-based palliation strategies have shown promising advantages over the conventional Blalock–Taussig–Thomas (BTT) shunt, with right ventricular outflow tract (RVOT) stenting emerging as a potentially transformative option in this setting.[2]
A patent ductus arteriosus (PDA) stent has recently emerged as an option, but it should be considered only if the PDA is patent. As an alternative, initial palliation with RVOT stenting has gained attention as a promising approach, with the additional advantage of potentially symmetrically augmenting blood flow to both sides. However, complete repair of TOF after an RVOT stent remains a challenging surgical arena. We sought to analyze surgical outcomes in this difficult subset of TOF with prior RVOT stenting at our center.
PATIENTS AND METHODS
Of the 619 TOF patients who underwent total repair at our center from April 2021 to March 2025, 11 with prior RVOT stenting were included in the study. Retrospective data were collected from hospital medical records. The Institutional Ethics Committee granted an exemption from review due to the retrospective nature of the study (NSHEV/INV/Non-Reg/2025/001; dated April 3, 2025). All demographic data, type of surgery, in-hospital mortality, ventilation duration, length of intensive care unit (ICU) stay, and postoperative hospital stay were collected. PA size data from prestent cardiac catheterization records were also collected, and growth in branch PA size was compared with presurgery branch PA size.
The protocol for using a palliative strategy for TOF at our institution is based on the clinical acuity and the branch PA size. If the branch PA size is <−2 z-score and there is a PDA, a ductal stent is offered, if the child is having a cyanotic spell or is very symptomatic. A BTT shunt is chosen when there is no PDA and the child is relatively stable. The absence of PDA, cyanotic spells, and small branch PA size would qualify these patients for an RVOT stent.
The study aimed to analyze the surgical outcomes of patients with TOF who underwent corrective surgery after prior palliation with an RVOT stent. The primary objective was to assess postoperative complications, including in-hospital morbidity and mortality. The secondary objective of this study was to evaluate growth in branch PAs in the interim period and to determine the interval between the RVOT stent and surgery and its implications for intraoperative duration, including cardiopulmonary bypass (CPB) time and aortic cross-clamp (ACC) time.
Inclusion–exclusion criteria
All patients undergoing corrective surgery for TOF with a prior RVOT stent as the first palliative procedure during the study period were included.
Preoperative assessment
The preoperative assessment included clinical examination, chest X-ray, echocardiography, and cardiac catheterization in selected cases before surgery.
Surgical techniques
All patients underwent standard surgical repair of TOF. Wherever possible, the entire RVOT stent was excised, taking care to preserve important structures, including the coronary arteries, the aortic valve, the septal band, and the moderator band. One patient underwent a partial stent excision due to dense adhesions on the septal band side. Most patients received a transannular patch (TAP) because the stent crossed the pulmonary valve, and the pulmonary annulus was restrictive.
Postoperative protocol
All patients were admitted to the ICU after the operation. The inotropic support consisted of milrinone (0.5 μg/kg/min) and norepinephrine (0.05 μg/kg/min). Inotropes were gradually tapered over 24–48 h.
All patients were weaned off ventilatory support as soon as possible if they were hemodynamically stable and there was no bleeding.
Statistical methods
All continuous variables were expressed as mean ± standard deviation, as well as median and interquartile range (IQR). Qualitative variables were expressed as numbers and percentages. The continuous variables were tested for normal distribution.
RESULTS
From April 2021 to March 2025, 619 patients underwent surgery or intervention for TOF at our institution. Among palliative interventions for TOF, 42 patients underwent systemic-to-PA shunts (BTT), 51 underwent PDA stenting, and 11 underwent RVOT stenting. These 11 patients with prior RVOT stenting who underwent TOF repair later were included in the study [Figure 1].
Figure 1.
Illustration of treatment pathways of tetralogy of Fallot patients. RVOT: Right ventricular outflow tract, TOF: Tetralogy of Fallot, PDA: Patent ductus arteriosus, BTT: Blalock–Taussig–Thomas
The patient characteristics are described in Table 1. The median age at surgery was 31 months (IQR: 60 months; range: 12–108 months). The median weight at surgery was 10.2 kg (IQR: 5.5 kg; range: 5.4–13.8 kg). Half of the patients were male. Prior to RVOT stent, the mean left PA z-scores were −1.92 (−0.42 to −3.31); the mean right PA z-scores were −2.95 (−0.15 to −3.91). The stents used were 4–6 mm in diameter with a length range of 20–24 mm. The mean duration from stenting to surgery was 10.5 ± 11.1 months. At preoperative evaluation, left and right PA z-scores were 0.11 (−3.6–2.89) and −0.46 (−2.4–2.31), respectively, indicating growth of the PAs. Analysis of temporal growth patterns showed that the maximum growth in PAs occurred during the first 5 months after RVOT stenting [Figure 2a and b].
Table 1.
Patient characteristics and surgical outcomes of tetralogy of Fallot repair after right ventricular outflow tract stent
| Characteristic | Number (n) |
|---|---|
| Total patients, n (%) | 11 (100) |
| Age at surgery (months), median (range) | 31 (12–108) |
| Weight at surgery (kg), median (range) | 10.2 (5.4–13.8) |
| Sex (male), n (%) | 7 (50) |
| Stent to surgery interval (months), mean±SD | 10.5±11.1 |
| Transannular patch, n (%) | 10 (90.9) |
| Coronary crossing RVOT, n (%) | 3 (27.2) |
| CPB time (min), mean±SD | 115.5±37.5 |
| Aortic cross clamp (min), mean±SD | 100.6±31.2 |
| Ventilation duration (h), median (range) | 12.7 (4–21.7) |
| ICU length of stay (days), mean±SD | 2.1±0.98 |
| Postoperative length of stay (days), mean±SD | 4.45±2.7 |
RVOT: Right ventricular outflow tract, SD: Standard deviation, CPB: Cardiopulmonary bypass, ICU: Intensive care unit
Figure 2.
(a) Left pulmonary artery growth with time, (b) Right pulmonary artery growth with time. LPA: Left pulmonary artery, RPA: Right pulmonary artery
A TAP was used in 90.9% of cases (10 out of 11). Stent excision was done carefully, preserving the vital intracardiac structures such as the moderator band, the anterior papillary muscle of the tricuspid valve, and the aortic valve [Figure 3a and b]. The RVOT stent was completely excised in 10 of 11 patients (90.9%), leaving a densely adherent portion partially on the septal band side in one patient. A major coronary artery crossing the RVOT was noted in 27.2% (3 out of 11) of the patients, necessitating a modified double-barrel repair for TOF[3] [Figure 3c]. The mean CPB time was 115.5 ± 37.5 min, and the mean ACC time was 100.6 ± 31.2 min. The interval from stent to surgery showed a direct correlation with CPB and ACC times [Figure 4]. The operative time increased with the longer we waited after the initial stenting, as shown in Figure 4. The median duration of mechanical ventilation was 12.7 h (IQR: 16.6 h; range: 4–21.7 h). The mean ICU length of stay was 2.1 ± 0.98 days, while the mean postoperative hospital stay was 4.45 ± 2.7 days [Table 1]. There was no in-hospital or 30-day mortality.
Figure 3.
(a) Transatrial view of right ventricular outflow tract stent, (b) Transpulmonary artery view of right ventricular outflow tract stent, (c) Double-barrel repair in a coronary artery crossing the right ventricular outflow tract
Figure 4.
Relationship between Cardiopulmonary bypass and aortic cross-clamp time and time from stent to surgery. ACC: aortic cross-clamp, CPB: Cardiopulmonary bypass
DISCUSSION
TOF is among the most common forms of cyanotic congenital heart disease. Although most patients now undergo elective complete repair between 3 and 9 months of age with excellent long-term outcomes, a distinct subset of patients – particularly neonates with severe cyanosis and unfavorable anatomy – present a significant surgical challenge.[1] In this group, palliation before total correction is often necessitated by factors such as low body weight, hypoplastic pulmonary arteries, or complex coronary anatomy.[2,4]
Recent advances in interventional cardiology have introduced RVOT stenting as an alternative palliative measure.[4,5] RVOT stenting aims to relieve RVOT obstruction and augment antegrade flow to both PAs, promoting more physiological and symmetrical PA growth. In contrast to BTT shunts, RVOT stents preserve the normal direction of blood flow and avoid sternotomy or thoracotomy, which can be advantageous for eventual surgical repair. In one of the earliest reports of RVOT stenting, Barron et al. showed that primary RVOT stenting offers a viable staged palliation strategy for small infants and those with complex TOF anatomy. In these 32 patients with RVOT stents, the procedure potentially optimized conditions for later definitive surgical repair.[4]
Sandoval et al. demonstrated that RVOT stenting (n = 42) is an effective bridging procedure allowing somatic and PA growth in a cohort of 180 patients with TOF who were grouped as RVOT stent (stent group, n = 44), primary repair <3 months of age with TOF-pulmonary stenosis (TOF-PS) (early-PS group, n = 44), primary repair <3 months of age with TOF-pulmonary atresia (TOF-pulmonary artery (PA)) (early-PA group, n = 49), and primary repair between 3 and 11 months of age (surgery >3 months of age, group, n = 45).[5] Pizzuto et al. showed in a recent review that RVOT stenting is a technically feasible, well-tolerated, and effective palliation in critical TOF patients, at similar or lower risk than surgical palliation.[6] Wilder et al. showed that early primary repair in neonates may lead to a higher likelihood of surgical reinterventions, and transcatheter palliation may require more catheter-based reinterventions; both approaches demonstrated similar results in terms of survival, somatic growth, and hemodynamic performance. This suggests that either strategy can be a viable option for managing severe TOF in children. Eighteen patients in this study had an RVOT stent as the initial palliation.[7] Recently, Juaneda et al. showed in a multicenter study from Argentina that surgical repair of severe TOF following RVOT stenting is a safe and effective approach, demonstrating no significant increase in perioperative morbidity or mortality.[8] Another recent study from southern India involving 20 patients showed that RVOT stenting is a safe and effective palliative management in TOF, increasing oxygen saturation prior to definitive surgical repair.[9]
However, despite its growing popularity, RVOT stenting alters the surgical landscape and introduces new operative challenges.[10,11] The surgical challenges posed by prior RVOT stenting are significant. In our series, 10 of 11 patients (90.9%) underwent complete excision of the RVOT stent. This suggests that stent removal is feasible in the majority of cases but not straightforward in all cases. One patient required partial stent retention due to dense adherence to the septal band – highlighting the potential for fibrotic incorporation of the stent over time. A report describing the inflammatory changes and in-stenosis after RVOT stent, along with histologic evidence of the same, corroborates our experience of dense stent adhesions in the muscular portion of the RVOT.[10] Careful dissection is mandatory to avoid injury to nearby vital structures such as the aortic valve, coronary arteries, and right ventricular structures. Such injury to vital structures, such as the aortic valve, has already been described in the literature.[11]
The predominance of TAP repair (90.9%) in this cohort aligns with the expectation that stent placement frequently spans the pulmonary annulus, thereby necessitating annular enlargement. This high TAP rate is comparable to other series that employed prior RVOT stenting and underscores the need for tailored surgical strategies to accommodate prior interventions.[4] If the PS is predominantly infundibular at the time of RVOT stenting, the interventional team should make sure the stent does not cross the pulmonary valve during initial placement, which makes future valve-preserving repair possible. In addition, during surgery, all efforts should be made to excise the stent, preserving the valve leaflets if the pulmonary annulus is appropriately sized. However, crossing the stent across the pulmonary annulus and the intense fibrotic reaction it generates often makes it impossible to preserve the pulmonary valve.
A key finding of this study is the correlation between increased interval from stenting to surgical repair and prolonged CPB and ACC times. Juaneda et al. also showed that the difficulty in stent extraction is related to the time since implantation.[8] These findings suggest that a delay in definitive surgery may lead to increased operative complexity, likely due to progressive fibrosis, tissue overgrowth, or stent incorporation into adjacent structures. While the median interval between stenting and surgery in our series was 10.5 months, the increase in surgical duration with time suggests that earlier repair, once adequate PA growth is achieved, may be advantageous. This observation advocates earlier repair once adequate PA growth is achieved – particularly within the first 5 months, when our analysis showed maximal PA growth. Beyond this window, diminishing returns in branch PA growth, coupled with increased surgical complexity, suggest a diminishing benefit from prolonged palliation.
A central hypothesis supporting RVOT stenting is that it facilitates PA development by increasing pulsatile antegrade flow.[1,2,4,8] Our findings support this principle, with z-scores of both left and right PAs improving from markedly hypoplastic values at baseline (mean LPA z: −1.92; RPA z: −2.95) to near-normal scores preoperatively (LPA z: 0.11; RPA z: −0.46). Importantly, this symmetrical and significant growth supports the argument that RVOT stenting offers a more physiological approach to promoting PA development than systemic-to-pulmonary shunting. This has been shown in other studies as well.[12,13,14]
Major coronary artery crossing the RVOT was noted in 27.2% (3 out of 11) of the patients, necessitating a modified double-barrel repair for TOF.[3] This was just an incidental finding, and the presence of anomalous coronaries was not a reason for the initial palliation strategy. Given the small sample size of 11 patients, the fraction of abnormal coronary patterns appears high. In a large series of 122 patients with RVOT stenting as initial palliation over 15 years, published by Afifi et al., only 10 patients had anomalous coronaries crossing the RVOT. They demonstrated the safety and effectiveness of this strategy in TOF with anomalous coronaries.[15]
Despite the surgical challenges, the postoperative outcomes in our cohort were favorable. The median mechanical ventilation duration of 12.7 h and ICU stay of approximately 2 days align with institutional benchmarks for standard TOF repair, suggesting that prior RVOT stenting does not necessarily prolong the recovery. Importantly, there was no in-hospital mortality in this cohort, and postoperative morbidity remained low. These findings reinforce the feasibility and safety of corrective surgery following RVOT stenting.
Compared with PDA stenting or BTT shunting, RVOT stenting offers several theoretical and observed advantages. It avoids sternotomy or thoracotomy, maintains more natural physiology, and promotes bilateral, balanced PA growth. However, it does entail a more complex second-stage operation due to stent excision and associated intracardiac dissection.[12,16,17] Furthermore, while BTT shunts often distort branch PAs or favor unilateral flow, RVOT stents maintain continuity of flow through the main PA.
Nevertheless, our findings reinforce that surgical repair after RVOT stenting is both feasible and safe, and that PA growth is significant in the initial months poststenting. A linear correlation was seen between the interval from stenting to surgical repair and CPB and ACC times. Future multicenter studies with larger cohorts and longer follow-up periods are needed to validate these findings. Establishing standardized timing for definitive repair after RVOT stenting based on objective metrics of PA growth and operative risk would further refine management in this challenging patient subset.
Limitations
This study is limited by its retrospective nature and small sample size, which preclude robust statistical comparisons. Additionally, long-term outcomes such as RV function, reintervention rates, and late arrhythmias remain to be assessed.
CONCLUSIONS
Surgical repair following RVOT stenting in TOF is safe and feasible despite being a challenging procedure. Early repair, ideally within 5 months poststenting, optimizes PA growth while minimizing surgical complexity and CPB duration. A longer interval between the RVOT stent and surgery increases operative time.
Conflicts of interest
There are no conflicts of interest.
Funding Statement
Nil.
REFERENCES
- 1.Rampengan SH, Surya SC, Rampengan DD, Willyanto SE, Ramadhan RN, de Liyis BG, et al. Determining the optimal timing for tetralogy of Fallot management: A meta-analysis of neonatal versus postneonatal repairs. Ann Pediatr Cardiol. 2025;18:1–12. doi: 10.4103/apc.apc_228_24. [DOI] [PMC free article] [PubMed] [Google Scholar]
- 2.Barron DJ, Jegatheeswaran A. How and when should tetralogy of Fallot be palliated prior to complete repair? Semin Thorac Cardiovasc Surg Pediatr Card Surg Annu. 2021;24:77–84. doi: 10.1053/j.pcsu.2021.02.002. [DOI] [PubMed] [Google Scholar]
- 3.Shivaprakasha K. Simplified double barrel repair with autologous pericardium for tetralogy of Fallot with hypoplastic pulmonary annulus and anomalous coronary crossing right ventricular outflow. Ann Pediatr Cardiol. 2008;1:34–7. doi: 10.4103/0974-2069.41053. [DOI] [PMC free article] [PubMed] [Google Scholar]
- 4.Barron DJ, Ramchandani B, Murala J, Stumper O, De Giovanni JV, Jones TJ, et al. Surgery following primary right ventricular outflow tract stenting for Fallot’s tetralogy and variants: Rehabilitation of small pulmonary arteries. Eur J Cardiothorac Surg. 2013;44:656–62. doi: 10.1093/ejcts/ezt188. [DOI] [PubMed] [Google Scholar]
- 5.Sandoval JP, Chaturvedi RR, Benson L, Morgan G, Van Arsdell G, Honjo O, et al. Right ventricular outflow tract stenting in tetralogy of Fallot infants with risk factors for early primary repair. Circ Cardiovasc Interv. 2016;9:e003979. doi: 10.1161/CIRCINTERVENTIONS.116.003979. [DOI] [PubMed] [Google Scholar]
- 6.Pizzuto A, Cuman M, Assanta N, Franchi E, Marrone C, Pak V, et al. Right ventricular outflow tract stenting as palliation of critical tetralogy of Fallot: Techniques and results. Hearts. 2021;2:278–87. [Google Scholar]
- 7.Wilder TJ, Van Arsdell GS, Benson L, Pham-Hung E, Gritti M, Page A, et al. Young infants with severe tetralogy of Fallot: Early primary surgery versus transcatheter palliation. J Thorac Cardiovasc Surg. 2017;154:1692–700.e2. doi: 10.1016/j.jtcvs.2017.05.042. [DOI] [PubMed] [Google Scholar]
- 8.Juaneda I, Peirone A, Diaz J, Azar I, Molinas R, Guevara A, et al. Tetralogy of Fallot repair after neonatal right ventricular outflow tract stenting: Initial multicenter experience in Argentina. World J Pediatr Congenit Heart Surg. 2023;14:222–6. doi: 10.1177/21501351221140097. [DOI] [PubMed] [Google Scholar]
- 9.Priyadarshini B, Kasturi S, Reddy SN, Mohanty S. Palliative right ventricular outflow tract stenting in tetralogy of Fallot with severe cyanosis: Experience from a single center in Southern India. Curr Med Issues. 2024;22:121–7. [Google Scholar]
- 10.Prabhu S, Mehra S, Kanaparthi S, Maiya SS, Rao S. Right ventricular outflow tract histology post-stenting and in-stent stenosis. Ann Pediatr Cardiol. 2022;15:206–8. doi: 10.4103/apc.apc_231_21. [DOI] [PMC free article] [PubMed] [Google Scholar]
- 11.Lee J, Sivalingam S, Alwi M. Stenting of right ventricular outflow tract in tetralogy of Fallot with subarterial ventricular septal defect: A word of caution. Ann Pediatr Cardiol. 2017;10:281–3. doi: 10.4103/apc.APC_168_16. [DOI] [PMC free article] [PubMed] [Google Scholar]
- 12.Quandt D, Ramchandani B, Penford G, Stickley J, Bhole V, Mehta C, et al. Right ventricular outflow tract stent versus BT shunt palliation in tetralogy of Fallot. Heart. 2017;103:1985–91. doi: 10.1136/heartjnl-2016-310620. [DOI] [PubMed] [Google Scholar]
- 13.Ho AB, Perry T, Hribernik I, Thomson JD, Bentham JR. Surgical versus transcatheter palliation for insufficient pulmonary blood supply in infants with cyanotic CHD. Cardiol Young. 2022;32:42–7. doi: 10.1017/S1047951121001505. [DOI] [PubMed] [Google Scholar]
- 14.Peirone A, Contreras A, Ferrero Guadagnoli A, Francucci V, Juaneda I, Cabrera M, et al. Right ventricular outflow tract stenting in severe tetralogy of Fallot: An option to the Blalock-Taussig shunt. Rev Argent Cardiol. 2019;87:125–30. [Google Scholar]
- 15.Afifi AR, Mehta C, Bhole V, Chaudhari M, Khan NE, Jones TJ, et al. Anomalous coronary artery in tetralogy of Fallot-feasibility of right ventricular outflow tract stenting as initial palliation. Catheter Cardiovasc Interv. 2022;100:105–12. doi: 10.1002/ccd.30223. [DOI] [PubMed] [Google Scholar]
- 16.Glatz AC, Petit CJ, Goldstein BH, Kelleman MS, McCracken CE, McDonnell A, et al. Comparison between patent ductus arteriosus stent and modified Blalock-Taussig shunt as palliation for infants with ductal-dependent pulmonary blood flow: Insights from the congenital catheterization research collaborative. Circulation. 2018;137:589–601. doi: 10.1161/CIRCULATIONAHA.117.029987. [DOI] [PubMed] [Google Scholar]
- 17.Yasa KP, Bhaskara NS, Pertiwi PF. Arterial duct stenting versus modified Blalock-Taussig shunt in patients with ductal-dependent pulmonary circulation: A systematic review and meta-analysis. Congenit Heart Dis. 2024;19:139–56. [Google Scholar]