Palliative Balloon Pulmonary Valvotomy Enhances Immediate Postoperative Outcomes in Severely Cyanotic Patients With Tetralogy of Fallot

Abstract

Background

Older patients with severe cyanosis from unrepaired tetralogy of Fallot (TOF) face high perioperative morbidity despite technically straightforward surgical repair. Chronic hypoxemia leads to myocardial metabolic adaptation, polycythemia, and increased susceptibility to reperfusion injury. Preoperative optimization may improve outcomes in this high-risk group.

Objective

To evaluate whether palliative balloon pulmonary valvotomy (BPV) before intracardiac repair (ICR) improves immediate postoperative outcomes in severely cyanotic patients with uncomplicated TOF.

Methods

A prospective observational study was conducted on 42 patients (age: 5 months-40 years) with severe cyanosis (oxygen saturation <70%) undergoing BPV followed by elective ICR. Pre and postoperative parameters including oxygen saturation, hemoglobin, hematocrit, ventilation duration, vasoactive inotrope score, intensive care unit (ICU) stay, and hospital stay were recorded. Outcomes were compared with 49 matched controls undergoing direct ICR without BPV.

Results

Balloon pulmonary valvotomy led to a mean saturation increase of 15 ± 3% in 90% of patients, with reported improvement in functional capacity and cessation of cyanotic spells. Compared with the direct ICR group, BPV-ICR patients had significantly shorter ventilation time (13.3 ± 13.8 vs 29.1 ± 37.4 h, P = .011), inotrope duration (46.9 ± 15.5 vs 64.3 ± 30.8 h, P = .001), ICU stay (62.9 ± 36.8 vs 94.9 ± 43.1 h, P < .001), and hospital stay (6.6 ± 3.6 vs 10.6 ± 2.8 days, P = .001). No mortality occurred in the BPV-ICR group versus two deaths in the control group.

Conclusions

Palliative BPV significantly improves preoperative condition and reduces immediate postoperative morbidity in severely cyanotic, anatomically suitable TOF patients. A staged BPV-ICR approach may be a safe, effective strategy in resource-limited settings.

Keywords

tetralogy of fallot severe cyanosis intracardiac repair balloon pulmonary valvotomy transannular patch repair

Introduction

Tetralogy of Fallot (TOF) with pulmonary stenosis is the most common cyanotic congenital heart defect, presenting across all age groups.¹ The classic anatomic features including ventricular septal defect (VSD), overriding aorta, right ventricular outflow tract (RVOT) obstruction, and right ventricular hypertrophy vary in severity. The degree of RVOT obstruction determines the clinical picture and prognosis. Improved survival in recent decades has led to two distinct patient cohorts beyond the first decade of life. One group maintains adequate pulmonary blood flow, sustaining oxygen saturation of 85% to 90% and remaining functionally compensated into adulthood. The second group, identified early in life but untreated, develops severe cyanosis, polycythemia, coagulation abnormalities, and end-organ dysfunction.² These patients are at risk for brain abscess, stroke, and infective endocarditis and often have markedly reduced exercise tolerance.

In India and similar low- and middle-income countries, pediatric cardiac services are concentrated in a few tertiary centers.³ Many patients with unrepaired TOF present late to public hospitals, facing long surgical waiting lists. Prolonged hypoxia alters myocardial metabolism,⁴ shifting from aerobic to anerobic energy pathways. Continuous monitoring and maintenance of optimal oxygen saturation are crucial in such patients, as both prolonged hypoxemia and excessive oxygen exposure can adversely affect clinical outcomes.^5,6 While adaptive, this metabolic remodeling predisposes the heart to ischemia-reperfusion injury during corrective surgery.⁷

Various preoperative interventions have been proposed to reduce hypoxia before definitive repair. Modified Blalock-Taussig-Thomas (mBTT) shunts and RVOT stenting can augment pulmonary blood flow but are associated with increased reperfusion injury and procedural risks.^8,9 Balloon pulmonary valvotomy (BPV), by contrast, is less invasive and can be performed during diagnostic catheterization. By partially relieving RVOT obstruction, BPV may improve oxygenation and functional status without provoking abrupt hemodynamic shifts. This study evaluates the role of palliative BPV in older, severely cyanotic TOF patients with suitable anatomy, comparing postoperative outcomes with a matched cohort undergoing direct intracardiac repair (ICR). We hypothesized that staged BPV-ICR would improve preoperative stability and reduce postoperative morbidity in this high-risk group.

Materials and Methods

Study Design and Setting

This prospective observational study was conducted at Sri Padmavathi Children's Heart Centre, Tirupati, Andhra Pradesh, India, a nonprofit tertiary pediatric cardiac facility. Data were collected between December 2021 and August 2024. The institutional Heart Team and ethical committee approved all interventions.

Patient Selection

Inclusion Criteria

Diagnosis of uncomplicated TOF with pulmonary stenosis.

Severe cyanosis (oxygen saturation <70%).

Suitable pulmonary valve and branch pulmonary artery anatomy on transthoracic echocardiogram (TTE).

Exclusion Criteria

Complex TOF variants (pulmonary atresia, hypoplastic branch pulmonary arteries, atrioventricular septal defects).

Previous palliation (systemic-pulmonary shunt, RVOT stenting, patent ductus arteriosus stenting).

Significant noncardiac comorbidities precluding ICR.

Preprocedure Evaluation

Baseline assessment included demographics, functional status, history of cyanotic spells, TTE measurements (z-scores for pulmonary valve annulus and branch pulmonary arteries), hemoglobin, hematocrit, and resting oxygen saturation. Baseline characteristics are summarized in Table 1.

Table 1.

Baseline Characteristics of Patients Undergoing Balloon Pulmonary Valvotomy (BPV) Before Intracardiac Repair (ICR).

Characteristics	Total patients n = 42 n (%)
Age
<1 year	6 (14%)
1-5 years	7 (17%)
5-10 years	10 (24%)
11-20 years	11 (26%)
>20 years	8 (19%)
Sex
Male	22 (52%)
Female	20 (48%)
Saturation (mean, stdev)	57 ± 8%
Hemoglobin (mean, stdev)	16.4 ± 3.5 g/dL
Hematocrit (mean, stdev)	57 ± 3.8
Pulmonary artery z score	−2.4 ± 0.4
Right pulmonary artery z score	−1.8 ± −0.6
Left pulmonary artery z score	−2.2 ± −0.8

Abbreviation: stdev, standard deviation.

Balloon Pulmonary Valvotomy Procedure

Balloon pulmonary valvotomy was performed within 24 hours of admission under brief intravenous sedation. Semicompliant balloons (Tyshak or Cordis) sized at 80% to 100% of the measured pulmonary valve annulus were used. The RVOT, including the infundibulum, was dilated. Graded dilatation was performed in severe stenosis. Standard catheterization included pigtail angiography of RVOT (post-BPV anatomy), left ventricle (additional VSD assessment), aortic root (coronary anatomy), and descending aorta (aortopulmonary collaterals). No additional procedures were performed. Patients were observed in the ICU for 24 hours postprocedure and discharged on postoperative day 2. The procedure is depicted in Figure 1.

Follow-up and Definitive Repair

Follow-up visits occurred at 10 days, 1 month and then every 3 months until corrective surgery. Assessments included symptom status, oxygen saturation at rest and on exertion, murmur characteristics and transthoracic echocardiography. All patients subsequently underwent ICR during follow-up.

Comparison Group

Outcomes were compared with age- and anatomy-matched severely cyanotic TOF patients undergoing direct ICR (native ICR group) between 2021 and 2024.

Outcome Measures

Primary endpoints:

Postoperative ventilation >18 h

Inotrope duration > 48 h

ICU stay >72 h

Vasoactive inotrope score (VIS) >10

Hospital stay >7 d

Secondary Endpoints

Low cardiac output syndrome (LCOS)

Junctional ectopic tachycardia (JET)

Mortality

Statistical Analysis

Data were analyzed using SPSS v22. Continuous variables are presented as mean ± SD or median (IQR) and compared using independent t tests. Categorical variables were compared using Pearson's χ² test. Logistic regression identified predictors of morbidity and mortality. Statistical significance was set at P < .05.

Results

Baseline Characteristics – Balloon Pulmonary Valvotomy Group

The BPV group consisted of 42 patients, with a nearly equal gender distribution (22 males, 20 females) (Table 1). Ages ranged from 5 months to 40 years, with the largest proportion in the 11 to 20 year group (11, 26%), followed by children aged 5 to 10 years (10, 24%). Six patients (14%) were infants, 7 (17%) were 1 to 5 years of age, and 8 (19%) were adults over 20 years. Preprocedure evaluation revealed profound hypoxemia, with a mean oxygen saturation of 57 ± 8%. Hemoglobin and hematocrit levels were elevated (16.4 ± 3.5 g/dL and ± 3.8%, respectively), reflecting chronic polycythemia secondary to long-standing cyanosis.

Echocardiographic assessment demonstrated predominantly infundibular and valvar pulmonary stenosis, with a mean pulmonary artery z-score of −2.4 ± 0.4. Branch pulmonary artery z-scores were also mildly reduced but within operable range (right −1.8 ± 0.6, left −2.2 ± 0.8).

Immediate Post-Balloon Pulmonary Valvotomy Outcomes

Balloon pulmonary valvotomy was successfully performed in all patients within 24 hours of admission, with no procedural mortality or complications such as reperfusion injury (Figure 2). Twenty-two of 42 patients (53%) required ICU stabilization before BPV due to severe cyanosis. At one month, 38/42 patients (90%) demonstrated an average oxygen saturation increase of 15 ± 3%, with several patients reporting complete cessation of cyanotic spells and improved exercise tolerance. Parents noted increased activity levels and fewer squatting episodes in children. Even in the minority without measurable saturation rise, subjective functional improvement was reported. The median interval between BPV and ICR was 148 days (mean 179 ± 127 days). During this period, hematocrit values decreased from 57% pre-BPV to 48% pre-ICR.

Surgical Outcomes – Balloon Pulmonary Valvotomy Group

All patients in the BPV group underwent successful ICR with no operative or late mortality. Preoperative oxygen saturation improved to a mean of 83 ± 6% at the time of surgery. Most patients underwent standard repair, while 5/42 patients (12%) required transannular patch augmentation. The mean cardiopulmonary bypass (CPB) time was 160 ± 53 min, and the mean aortic cross-clamp time was 105 ± 38 min, comparable with standard TOF repair durations (Table 2).

Table 2.

Comparison of Baseline Characteristics Between BPV-ICR and Native ICR Groups.

Variable	BPV-ICR N = 42	Native ICR N = 49	P value
Infants	4 (9%)	6 (12%)	1.00
Weight, mean ± SD	10.69 ± 8.54	8.55 ± 7.46	.122
Height, mean ± SD	114.92 ± 33.55	106.02 ± 32.38	.542
Pulmonary artery z score, mean ± SD	−2.4 ± 0.4	−2.6 ± 0.6	.61
Right pulmonary artery z score, mean ± SD	−1.8 ± −0.6	−2.0 ± 0.5	.71
Left pulmonary artery z score, mean ± SD	−2.2 ± −0.8	−2.4 ± 1.0	.32
Hemoglobin, mean ± SD	15.78 ± 3.35	17.43 ± 2.74	.171
Saturation, mean ± SD	83.47 ± 6.22	66.14 ± 7.41	<.001^a
Hematocrit, mean ± SD	48.19 ± 8.81	54.87 ± 6.30	<.001^a
Preoperative ICU stay, n (%)	1 (2.3)	17 (35)	<.001^a
CPB time (min), Mean ± SD	160.5 ± 53.61	156.57 ± 46.65	.709
ACC time (min), Mean ± SD	105.16 ± 37.79	100.57 ± 38.72	.570

Abbreviations: ACC, aortic cross-clamp; BPV, balloon pulmonary valvotomy; CPB, cardiopulmonary bypass; ICR, intracardiac repair; ICU, intensive care unit; SD, standard deviation.

^aStatistically significant, P < .05.

Postoperatively, the mean ventilation time was 13 ± 6 h (median 11.5 h), well below high-risk thresholds, and the mean inotrope duration was 47 ± 15 h. Low cardiac output syndrome occurred in 2/42 patients (4.8%): one with single-lung physiology and another who required a large transannular patch and subsequently developed junctional ectopic tachycardia (JET) and septicemia. The mean ICU stay was 63 ± 36 h and the mean hospital stay was 6.5 ± 3.5 days. The mean VIS was 7.3 ± 4.1, reflecting modest postoperative support requirements.

Comparison With Native Intracardiac Repair Group

The native ICR group (n = 49) was demographically and anatomically comparable but had significantly lower preoperative oxygen saturation (66 ± 7%, P < .001) and higher hematocrit (54.9 ± 6.3%, P < .001). Compared with the native ICR group, BPV-ICR patients demonstrated shorter ventilation time (13.3 ± 13.8 h vs 29.1 ± 37.4 h, P = .011), reduced inotrope duration (46.9 ± 15.5 h vs 64.3 ± 30.8 h, P = .001), lower incidence of LCOS (4.8% vs 32.6%, P = .001), shorter ICU stay (62.9 ± 36.8 h vs 94.9 ± 43.1 h, P < .001), shorter overall hospital stay (6.6 ± 3.6 vs 10.6 ± 2.8 days, P = .001), and lower mean VIS (7.3 ± 4.1 vs 11.2 ± 6.8, P = .001). There were 2/49 deaths (4.1%) that occurred in the native ICR group, both in patients undergoing transannular patch repair who experienced severe postoperative complications, including LCOS and septicemia (Table 3, Figure 3).

Table 3.

Comparison of Postoperative Morbidity and Mortality Between BPV-ICR and Native ICR Groups.

Variable	BPV-ICR, n = 42	Native ICR, n = 49	P value
Duration of ventilation (h) Mean ± SD	13.31 ± 13.77	29.12 ± 37.36	.011
Duration of inotropes (h) Mean ± SD	46.90 ± 15.49	64.28 ± 30.76	.001
LCOS, n (%)	2 (11.1)	16 (88.9)	.001
Average VIS	7.3 ± 4.1	11.16 ± 6.8	.001
ICU duration (h) Mean ± SD	62.85 ± 36.78	94.89 ± 43.15	<.001
Hospital stay (days) Mean ± SD	6.57 ± 3.58	10.63 ± 2.84	.001
Complications on follow-up, n (%)	1 (2%)	3 (6%)	.621

Abbreviations: BPV, balloon pulmonary valvotomy; ICR, intracardiac repair; ICU, intensive care unit; LCOS, low cardiac output syndrome; VIS, vasoactive inotrope score.

Predictors of Morbidity

On univariate logistic regression, low preoperative saturation (<70%), high hematocrit (>50), and preoperative ICU stay were significantly associated with prolonged ventilation (>18 h), extended inotropic support (>48 h), and longer ICU/hospital stays (>7 d) (Table 4).

Table 4.

Univariate Logistic Regression Analysis of Predictors for Morbidity and Mortality.

Variable	Unadjusted odds ratio (95% C.I†)	P value
DURATION OF VENTILATION
Hb >15 g/dL	2.36 (0.71-7.79)	.158
Saturation <70%	3.08 (1.22-7.76)	.017^a
Hct >50	6.66 (2.07-21.41)	.001^a
Preop ICU stay	2.94 (1.14-7.76)	.029^a
DURATION OF ICU STAY
Hb >15 g/dL	10.62 (3.18-35.5)	<.001^a
Saturation <70%	8.25 (2.5-26.49)	<.001^a
Hct >50	6.46 (2.5-16.39)	<.001^a
Preop ICU stay	7.21 (1.9-26.49)	.003^a
DURATION OF INOTROPESE DURATION
Hb >15 g/dL	4.88 (1.73-13.77)	.003^a
Saturation <70%	6.22 (1.69-22.78)	.006^a
Hct >50	5.1 (1.9-13.45)	.001^a
Preop ICU stay	6.54 (1.4-30.23)	.016^a
DURATION OF HOSPITAL STAY
Hb >15 g/dL	6 (1.6-22.21)	.007^a
Saturation <70%	2.76 (1.13-6/76)	.025^a
Hct >50	12.9 (4-41.86)	<.001^a
Preop ICU stay	2.5 (0.96-6.50)	.059
AVERAGE VASOACTIVE INOTROPE SCORE
Hb >15 g/dL	5.6 (1.2-26.06)	.028^a
Saturation <70%	2.16 (0.862-5.44)	.100
Hct >50	6.19 (1.9-19.91)	.002^a
Preop ICU stay	1.94 (0.73-5.15)	1.81
DEATH
Hb >15 g/dL	0 (0)	.998
Saturation <70%	1.96 (0.11-32.5)	.637
Hct >50	0 (0)	1.000
Preop ICU stay	2.87 (0.17-47.76)	.463

Abbreviation: CI, confidence interval; ICU, intensive care unit.

Statistically significant, P < .05.

Multivariate analysis confirmed high hematocrit as the most consistent independent predictor of morbidity across outcomes, with adjusted odds ratios ranging from 4.5 to 10.2 for adverse postoperative parameters (Table 5).

Table 5.

Multivariate Logistic Regression Analysis of Independent Predictors for Morbidity Outcomes.

Dependent variable	Independent variable	Adjusted odds ratio (95% CI^†)	P value
Ventilator stay	HCT > 50	5.49 (1.6-18.16)	.005^a
Pre ICU admission stay	HB > 15 g/dL	5.77 (1.2-26.1)	.023^a
Hospital stay	HCT > 50	10.17 (2.5-40.72)	.001^a
AV VIS	HCT > 50	4.5 (1.18-17.10)	.027^a

Abbreviations: CI, confidence interval; ICU, intensive care unit; VIS, vasoactive inotrope score.

Statistically significant, P < .05.

Discussion

Profoundly cyanotic older patients with simple TOF remain a surgical challenge despite technically straightforward repairs. Long-standing hypoxemia induces multiple pathophysiological changes: myocardial remodeling, elevated hematocrit, hyperviscosity, and altered coagulation.¹⁰ At the cellular level, there is a shift toward anerobic glycolysis, reduced mitochondrial oxidative capacity, and changes in calcium handling, all of which can impair myocardial recovery after CPB.^4,11 These adaptations, while compensatory for chronic hypoxia, render the myocardium more susceptible to ischemia-reperfusion injury during corrective surgery.^7,12 Preoperative optimization is therefore critical. Prior studies have shown that improved oxygen saturation before surgery correlates with shorter ventilation times and reduced postoperative morbidity.^13,14 In our cohort, BPV provided this benefit without introducing the risks associated with systemic-pulmonary shunts or RVOT stenting.

Previous reports of BPV as interim palliation have largely focused on young infants, demonstrating that BPV can safely increase pulmonary blood flow, reduce cyanotic spells, and defer or simplify early surgical repair.¹⁴ Infant series typically emphasize feasibility in small anatomy, short-term avoidance of urgent surgery, and facilitation of somatic growth prior to definitive repair. By contrast, infants differ from older patients in several important ways such as smaller annuli and branch pulmonary arteries, different responses to volume loading, and markedly different patterns of myocardial maturation and oxygen delivery requirements.

Our study extends these observations into an older, heterogeneous cohort (ages 5 months to 40 years) of severely cyanotic, unrepaired TOF patients and shows clinically important downstream benefits that were not the principal endpoints of infant series. In our cohort, BPV produced a sustained rise in preoperative oxygen saturation and a fall in hematocrit before ICR and was associated with significantly shorter postoperative ventilation times, lower vasoactive inotrope requirements, reduced ICU duration, and shorter hospital stay compared with anatomy and age matched direct-repair controls. These outcome measures which reflect perioperative myocardial tolerance to reperfusion and systemic response to surgery are particularly relevant in older, chronically hypoxemic patients who manifest established polycythemia and long-standing myocardial metabolic adaptation. Thus, while infant BPV studies primarily document immediate palliative success and buy time for growth, our data provide new evidence that BPV may also improve immediate postoperative recovery and reduce perioperative morbidity in older, severely cyanotic patients.

Mechanistic Rationale for Balloon Pulmonary Valvotomy

Balloon pulmonary valvotomy relieves valvar and subvalvar obstruction, increasing antegrade pulmonary blood flow. According to Poiseuille's law, even a small increase in pulmonary valve diameter markedly increases flow (four fold), improving arterial oxygen saturation and reducing polycythemia. Unlike surgical shunts, BPV preserves native RVOT anatomy, avoiding distortion of pulmonary arteries or risk of shunt thrombosis.⁸ Compared with RVOT stenting, BPV does not involve permanent hardware and avoids neointimal proliferation, which can complicate later surgery.¹⁵

Comparison With Other Palliation Strategies

Modified BTT shunts are effective at increasing pulmonary blood flow but are associated with significant early morbidity and mortality in older, polycythemic patients.¹⁶ Right ventricular outflow tract stenting offers a catheter-based alternative, but procedural complexity, need for large sheaths, and potential for vascular injury limit its applicability in small children and those with fragile pulmonary arteries.¹⁷ Balloon pulmonary valvotomy is technically simpler, can be performed during diagnostic catheterization, and does not preclude future surgical options. Our findings are in line with Remadevi et al,¹⁴ who demonstrated BPV's effectiveness in young infants as interim palliation. Kalavrouziotis et al.⁹, Jonas and Castaneda¹⁸ and Castaneda et al.¹⁹ have shown that staged strategies—whether with shunt, stent, or valvotomy—reduce operative risk when initial palliation improves hemodynamics. We extend this evidence to older, severely cyanotic TOF patients in resource-limited settings. These findings are consistent with recent large-scale evidence showing that RVOT reconstruction with valve substitutes, including TOF patients, yields low early mortality (∼1.95%) and acceptable late outcomes, although reinterventions remain inevitable and lifelong follow-up is essential.²⁰

Applicability in Resource-Limited Settings

In many low- and middle-income countries, where surgical waiting times are long and late presentation is common, BPV offers a low-cost, reproducible method of improving surgical readiness. The procedure can be performed in any center with basic pediatric interventional capability, requires no specialized consumables beyond standard valvotomy balloons, and adds minimal hospital stay. Training requirements are modest for operators experienced in congenital catheterization.

Study Implications and Future Research

The main implication is that staged BPV-ICR should be considered in older TOF patients with severe cyanosis and suitable anatomy, particularly where immediate surgery is not feasible. Larger multicenter studies with long-term follow-up are needed to assess whether the early benefits translate into improved late survival, reduced reintervention rates, and better right ventricular function. Indeed, recent midterm outcome data from adult TOF cohorts confirm that delayed repair can still achieve good survival, although reoperation rates—primarily for pulmonary valve replacement—are higher in patients beyond the third decade of life.²¹ Similar midterm results have also been reported in other adult TOF cohorts.^22,23

Limitations

This is a single-center study with only short- and medium-term follow-up.

Conclusions

Older, severely cyanotic patients with anatomically suitable TOF represent a high-risk subgroup in public cardiac centers. Palliative BPV performed during diagnostic catheterization can significantly improve preoperative condition, allowing safer elective repair with reduced morbidity. In resource-limited settings, this staged approach may be a practical, low-risk alternative to more invasive palliations. Larger, multicenter prospective studies are warranted to confirm these findings and refine patient selection criteria.

Footnotes

Abbreviations

Funding

The author(s) received no financial support for the research, authorship, and/or publication of this article.

Declaration of Conflicting Interests

The author(s) declared no potential conflicts of interest with respect to the research, authorship, and/or publication of this article.

ORCID iD

Sowmya Kasturi

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