Tetralogy of Fallot (TOF) in India and UAE | Complete Patient Guide

• ELIGIBLE PATIENTS — PEDIATRIC:

• Neonates and infants (3–12 months) with confirmed TOF on echocardiography, presenting with cyanosis (SpO2 < 85%), failure to thrive, or recurrent hypercyanotic spells

• Children aged 1–10 years with unrepaired or incompletely palliated TOF (post-BTT shunt or RV-PA conduit) deemed ready for complete intracardiac repair

• Patients with TOF variants including TOF with pulmonary atresia (TOF/PA), TOF with absent pulmonary valve syndrome (TOF/APV), and TOF with atrioventricular septal defect (TOF/AVSD)

• ELIGIBLE PATIENTS — ADOLESCENT/ADULT (ACHD):

• Patients with previously repaired TOF and hemodynamically significant free pulmonary regurgitation (RVESVI > 80 mL/m², RVEDVI > 150–160 mL/m² on cardiac MRI)

• Adults with residual VSD (Qp:Qs ≥ 1.5:1), residual RVOTO (peak Doppler gradient > 40 mmHg), or significant tricuspid regurgitation

• Candidates for transcatheter pulmonary valve replacement (TPVR) with suitable RVOT conduit morphology (conduit diameter ≥ 16 mm)

• REQUIRED DIAGNOSTIC WORKUP:

• Two-dimensional and Doppler echocardiography (transthoracic ± transesophageal): anatomy of VSD, RVOT, pulmonary valve annulus Z-score, aortic override, coronary artery anatomy

• Cardiac MRI (CMR): gold standard for quantifying RV volumes (RVEDVI, RVESVI), ejection fraction, and degree of pulmonary regurgitation (regurgitant fraction >25% is clinically significant)

• Cardiac catheterization with angiography: pulmonary artery anatomy, pulmonary artery pressures, coronary anatomy (especially anomalous left anterior descending from right coronary artery — present in ~5% of TOF cases, mandating surgical strategy modification)

• CT angiography (CTA): pulmonary artery branch anatomy, conduit calcification assessment for TPVR candidates

• Complete blood count (CBC): polycythemia, iron-deficiency anemia

• Coagulation profile (PT, aPTT, INR): pre-CPB assessment

• Chromosomal microarray / FISH for 22q11.2 deletion (DiGeorge syndrome): present in ~15–20% of TOF cases; affects immunological management and calcium homeostasis perioperatively

• Genetic testing / next-generation sequencing panel if syndromic features (Down syndrome, CHARGE, Alagille) are present

• Chest X-ray: classic 'boot-shaped heart' (coeur en sabot)

• 12-lead ECG and Holter monitoring: right bundle branch block (RBBB), QRS duration (a QRS duration > 180 ms is an independent risk factor for sudden cardiac death in repaired TOF)

• CONTRAINDICATIONS / HIGH-RISK FEATURES:

• Severe, fixed pulmonary arterial hypertension (PAH) with Eisenmenger physiology (pulmonary vascular resistance index >8 Wood units·m² unresponsive to vasodilator testing) — absolute contraindication to VSD closure

• Active systemic infection or sepsis prior to elective repair

• Prohibitively elevated operative risk due to severe comorbidities (e.g., advanced hepatic or renal failure in ACHD patients)

• Severely hypoplastic pulmonary arteries with Nakata index < 150 mm²/m² may require staged unifocalization prior to complete repair in TOF/PA with major aortopulmonary collateral arteries (MAPCAs)

TOF repair encompasses a spectrum of interventions ranging from palliative neonatal procedures to definitive intracardiac repair and, subsequently, late reintervention for residual or recurrent lesions.

1. PALLIATIVE PROCEDURES (Bridge to Complete Repair):

• Modified Blalock–Taussig–Thomas (mBTT) Shunt: A 3.5–4 mm Gore-Tex interposition graft connecting the subclavian artery to the ipsilateral pulmonary artery, performed in critically cyanotic neonates (<3 kg) unfit for primary repair. Improves pulmonary blood flow and allows somatic growth before definitive surgery.

• Central Aortopulmonary Shunt: Used when subclavian anatomy is unfavorable.

• RV-to-PA Conduit (Sano modification): Preferred in TOF/PA to provide forward pulsatile pulmonary flow.

• Pulmonary Balloon Valvuloplasty: Occasionally used as palliation in selected cases with predominantly valvular obstruction.

2. COMPLETE INTRACARDIAC REPAIR (DEFINITIVE — PRIMARY TREATMENT):

• Operative Access: Standard median sternotomy with cardiopulmonary bypass (CPB); aortic cross-clamping; cardioplegia (del Nido or Buckberg crystalloid solution commonly used in pediatric centers) for myocardial protection.

• Transatrial-Transpulmonary (TAT) Approach: The preferred contemporary technique. The RVOT and VSD are accessed via the right atrium and pulmonary artery, avoiding a right ventriculotomy entirely or limiting it to a minimal incision. This preserves RV muscle mass, reduces late RV dysfunction, and lowers the risk of arrhythmia compared to the traditional right ventriculotomy approach.

• Right Ventriculotomy Approach: Reserved for cases with extensive infundibular muscle bundles or anomalous coronary arteries crossing the RVOT that preclude safe TAT access.

• VSD Closure: Patch closure using a Dacron patch or autologous glutaraldehyde-treated pericardium with interrupted or continuous polypropylene sutures, ensuring adequate margins to avoid heart block (proximity to the bundle of His).

• RVOT Reconstruction Options:

a. Pulmonary Valve–Sparing Repair (PVS): Achieved by infundibular muscle resection, pulmonary commissurotomy, and annuloplasty when the pulmonary valve annulus Z-score is ≥ −2. This is the preferred strategy as it preserves valve competence and reduces long-term PR burden.

b. Transannular Patch (TAP): Required when the pulmonary annulus Z-score is < −2 to −3. A pericardial or synthetic patch is sutured across the annulus, relieving obstruction but inevitably creating free pulmonary regurgitation. Decision-making is guided by intraoperative assessment using the Nakata index and McGoon ratio.

c. RV-to-PA Conduit Implantation: Indicated in TOF with pulmonary atresia or severely anomalous pulmonary valve. Options include cryopreserved homografts (pulmonary or aortic), bovine jugular vein conduits (Contegra™), or porcine-valved conduits.

• Intraoperative TEE Monitoring: Mandatory to confirm adequacy of VSD patch closure, assess residual RVOTO (peak gradient < 25–30 mmHg target), evaluate pulmonary valve function, and detect any iatrogenic lesions before chest closure.

3. LATE REINTERVENTION FOR REPAIRED TOF:

• Surgical Pulmonary Valve Replacement (PVR): Re-do sternotomy; implantation of a tissue bioprosthesis (e.g., Carpentier-Edwards Perimount, Mosaic) or homograft. Indicated in late PR with RVEDVI > 150–160 mL/m² on CMR or symptomatic RV dysfunction.

• Transcatheter Pulmonary Valve Replacement (TPVR):

- Melody™ Valve (Medtronic): A bovine jugular vein valve mounted on a platinum-iridium stent; approved for conduit dysfunction in patients with suitable conduit diameter (16–22 mm).

- Edwards SAPIEN XT™ / SAPIEN 3™: Balloon-expandable transcatheter valve deployable in native RVOT or large conduits; extends the TPVR option to patients with larger anatomies.

- Advantage: Avoids re-do open-heart surgery; shorter hospitalization (2–4 days); same hemodynamic outcomes as surgical PVR in appropriate candidates.

• Catheter-Based Interventions: Balloon dilation or stenting of residual/recurrent branch PA stenosis; electrophysiological ablation or ICD implantation for sustained ventricular tachycardia (VT) arising from RVOT scar tissue (a significant cause of late sudden cardiac death in repaired TOF).

4. ADVANCED TECHNOLOGIES AVAILABLE AT PARTNER CENTERS:

• High-fidelity 3D cardiac MRI for pre-operative virtual surgical planning

• 3D-printed cardiac models for complex anatomies (TOF/PA, TOF/AVSD)

• Real-time intraoperative transesophageal echocardiography (TEE) with 3D matrix-array probes

• Near-infrared spectroscopy (NIRS) cerebral oximetry monitoring during CPB

• Minimally invasive robotic-assisted approaches (investigational in selected ACHD reoperations at advanced centers)

PHASE 1 — PRE-OPERATIVE EVALUATION (Days 1–5 in country):

• Day 1: GAF Healthcare coordinator receives the patient's medical records remotely and arranges an initial teleconsultation with the designated pediatric cardiac surgeon and congenital cardiologist at the chosen partner hospital.

• Days 1–2 (on arrival): Airport reception, hotel or hospital guest house check-in for the patient's family. The patient is admitted to the pediatric cardiac assessment unit.

• Days 2–5: Complete diagnostic workup performed in-hospital — transthoracic echocardiography (TTE), cardiac MRI (CMR), CTA of the pulmonary arteries, cardiac catheterization if indicated, 22q11.2 FISH, complete metabolic panel, coagulation profile, blood typing, and crossmatch. Pre-anesthetic evaluation, pediatric anesthesiology consultation, and ICU team briefing.

• Day 4–5: Multidisciplinary team (MDT) meeting between cardiac surgery, congenital cardiology, cardiac anesthesia, perfusion, and cardiac nursing. Surgical plan finalized, informed consent obtained in the patient's language (GAF-provided interpreter present).

• Baseline weight optimization: Malnourished infants may require 1–2 weeks of pre-operative nasogastric feeding or NG supplementation prior to elective surgery. If urgent, surgery proceeds without delay.

PHASE 2 — THE SURGICAL PROCEDURE (Day 6 approximately):

• The patient is brought to the operating room (OR) typically in the early morning, fasted for 4–6 hours (clear fluids) or per pediatric anesthesia protocol.

• Induction of general anesthesia; arterial line, central venous catheter, urinary catheter, and rectal temperature probe placement.

• Median sternotomy; cannulation of the ascending aorta and bicaval venous cannulation for cardiopulmonary bypass (CPB).

• Cooling to 28–32°C moderate hypothermia; aortic cross-clamp application; del Nido or Buckberg cardioplegia delivered antegrade.

• Transatrial-transpulmonary (TAT) approach: right atriotomy and pulmonary arteriotomy for intracardiac visualization.

• Infundibular muscle bundle resection; pulmonary commissurotomy and/or valvotomy; intraoperative measurement of pulmonary annulus diameter versus body surface area (Z-score determination).

• VSD patch closure with running 5-0 or 6-0 polypropylene suture and autologous pericardial or Dacron patch.

• RVOT augmentation: pulmonary valve–sparing repair if annulus Z-score ≥ −2; otherwise transannular pericardial patch.

• De-airing maneuvers; aortic cross-clamp released; cardiac resuscitation; weaning from CPB with inotropic support (dopamine, milrinone — a phosphodiesterase-3 inhibitor that reduces RV afterload and is the pharmacological cornerstone of post-TOF-repair hemodynamic support).

• Intraoperative TEE: confirm VSD patch competence (no residual shunt), assess RVOT peak gradient (target < 25 mmHg), evaluate tricuspid valve function.

• Pacing wires placed on RV and RA; mediastinal and pericardial chest drains inserted; sternal closure. Total operative time: approximately 3–5 hours.

PHASE 3 — PEDIATRIC CARDIAC ICU (PCICU) (Days 1–5 post-op):

• Day 0–1 (immediate post-op): Mechanical ventilation; continuous hemodynamic monitoring (arterial line, CVP); milrinone infusion (0.25–0.75 mcg/kg/min) for RV afterload reduction; low-dose dopamine for renal perfusion; strict fluid management to avoid RV volume overload.

• Day 1–2: Extubation trials; transition to nasal CPAP or high-flow nasal cannula if tolerated; chest drain output monitoring; pacing wire assessment.

• Day 2–3: Successful extubation in uncomplicated cases; oral feeding resumed (breastfeeding or formula for infants); diuretic therapy (furosemide) to manage post-CPB fluid retention; introduction of oral captopril (ACE inhibitor) if residual PR is anticipated.

• Day 3–5: Pacing wire removal; chest drain removal; mobilization to the PCICU chair; telemetry for arrhythmia detection (junctional ectopic tachycardia — JET — is the most common post-TOF-repair arrhythmia, managed with amiodarone and cooling).

• Echocardiography performed on Day 3–5 to document VSD closure, RVOT gradient, and ventricular function.

PHASE 4 — CARDIAC WARD (Days 6–14 post-op):

• Transfer from PCICU to the pediatric cardiac ward once hemodynamically stable and off vasoactive infusions.

• Gradual increase in oral feeds and activity; weight gain monitoring; wound care for the sternal incision.

• Oral medications established: furosemide, spironolactone (potassium-sparing diuretic), captopril, aspirin (antiplatelet therapy per center protocol).

• Pre-discharge echocardiogram, 12-lead ECG, chest X-ray.

• Day 10–14: Discharge from hospital, contingent on stable hemodynamics, adequate feeding, no arrhythmia, and clean wound.

PHASE 5 — IN-COUNTRY RECOVERY (Weeks 3–6 post-op):

• The patient and family stay in GAF Healthcare–arranged accommodation near the hospital.

• Weekly outpatient review with the congenital cardiologist: clinical examination, oxygen saturation, weight, wound inspection, and echocardiography.

• Sternal precautions maintained: no lifting of the child by the arms for 6–8 weeks (lift from the bottom); infant carriers and car seat protocols explained.

• Genetic counseling appointment for families with identified 22q11.2 deletion.

• By Week 4–6: Repeat echocardiogram and, if required, cardiac MRI to document RV volumes; treating cardiologist issues the formal 'fit-to-fly' clearance letter specifying oxygen supplementation needs (if any) and emergency contact instructions for the flight.

PHASE 6 — LONG-TERM FOLLOW-UP (Lifelong):

• Annual cardiology review for all repaired TOF patients — minimum every 12–24 months throughout life.

• Cardiac MRI every 3–5 years to track RV volumes and pulmonary regurgitant fraction.

• QRS duration monitoring on ECG; electrophysiology study (EPS) if QRS > 180 ms.

• GAF Healthcare provides a structured telemedicine follow-up plan connecting the patient's home cardiologist with the treating center's ACHD team for the first 12 months post-discharge.