Minimally Invasive Management in CHD

Introduction to Minimally Invasive Modalities

• Minimally invasive management encompasses transcatheter interventions, fetal cardiac procedures, and hybrid approaches.
• Offers definitive or palliative treatment with reduced surgical trauma, avoidance of cardiopulmonary bypass (CPB), and rapid recovery.
• High-technology hybrid catheterization laboratories combine fluoroscopic imaging with operating suites for complex lesion management.

Fetal Cardiac Interventions (FCI)

• Goal involves altering natural history in utero to improve postnatal morbidity and mortality.
• Minimally invasive approach utilizes ultrasound-guided 18/19-gauge cannula puncture through maternal abdomen, uterine wall, and fetal chest wall directly into target cardiac chamber.

Fetal Lesion	Intervention	Procedural Technique & Hemodynamic Goal
Severe Aortic Stenosis (AS)	Fetal Aortic Valvuloplasty	Balloon advanced across aortic annulus; inflated 100-120% of annulus size. Goal: Prevent evolving hypoplastic left heart syndrome (HLHS) and promote biventricular circulation.
Pulmonary Atresia/Critical PS	Fetal Pulmonary Valvuloplasty	Performed for intact ventricular septum to prevent evolving hypoplastic right heart syndrome (HRHS).
HLHS with Restrictive Atrial Septum	Fetal Atrial Septoplasty	Balloon dilation or septal stent placement for established HLHS with intact/restrictive atrial septum. Goal: Improve neonatal stability.

Transcatheter Septal Defect Closures

Atrial Septal Defect (ASD) & Patent Foramen Ovale (PFO)

• Standard therapy for secundum ASDs and PFOs with sufficient tissue margins.
• Procedure guided by intracardiac echocardiography (ICE) or 3D transesophageal echocardiography (TEE).
• Femoral vein access standard; transhepatic approach preferred if bilateral femoral venous occlusion exists.
• Superior sinus venosus ASDs may utilize covered stents (chimney technique).

Ventricular Septal Defect (VSD)

• Device closure standard for muscular and perimembranous VSDs.
• Approaches include antegrade (venous) or retrograde (arterial) delivery systems.
• Membranous VSD closure carries small risk of complete heart block.

Patent Ductus Arteriosus (PDA)

• Closure indicated to treat heart failure and prevent pulmonary vascular disease or endarteritis.
• Small PDAs managed with intravascular coils.
• Moderate-to-large PDAs managed with umbrella devices, vascular plugs (e.g., Nit-Occlud).
• Stenting of PDA serves as alternative to surgical Blalock-Taussig shunt in duct-dependent pulmonary circulation.

Transcatheter Valvular Interventions

Target Valve	Pathophysiology	Catheter Intervention	Clinical Notes & Outcomes
Pulmonary Valve	Congenital Pulmonary Stenosis	Balloon Pulmonary Valvotomy	First-line treatment of choice. High procedural success replacing open valvotomy.
Pulmonary Valve	RVOT dysfunction (stenosis/regurgitation)	Transcatheter Pulmonary Valve (TPV) Replacement	Devices include Melody (bovine jugular vein in stent), Sapien, Harmony, and Alterra prestent. Avoids redo sternotomy.
Aortic Valve	Congenital Aortic Stenosis	Balloon Aortic Valvuloplasty	First-line therapy in neonates/children. High recurrence of stenosis and iatrogenic aortic regurgitation risk.
Aortic Valve	Degenerative / Severe AS	Transcatheter Aortic Valve Replacement (TAVR)	Increasingly utilized in older adult CHD patients with high surgical risk.
Mitral Valve	Rheumatic Mitral Stenosis	Balloon Mitral Valvuloplasty (PMBC)	Inoue balloon technique used. Highly successful for fused commissures. Contraindicated for significant regurgitation or LA thrombus.
Mitral Valve	Mitral Regurgitation	MitraClip	Catheter-delivered clip creates double-orifice valve to reduce insufficiency; investigational in pediatrics.
Tricuspid Valve	Degenerated Bioprosthesis	Transcatheter Valve-in-Valve (TVIV) Implantation	Minimally invasive treatment for failing surgical valves (e.g., in Ebstein anomaly). Excellent hemodynamic outcomes.

Vascular Transcatheter Interventions

Coarctation of Aorta (CoA)

• Balloon angioplasty with or without stent placement.
• Preferred intervention in older children and adults.
• Neonates optimally managed with surgery due to high risk of recurrence, arterial aneurysm, and dissection with balloon therapies.

Pulmonary Artery (PA) Stenosis

• Managed with balloon dilation and stent implantation.
• Cutting balloon angioplasty utilized for highly challenging, small-vessel PA stenoses and in-stent restenosis.
• Major aortopulmonary collateral arteries (MAPCAs) in Tetralogy of Fallot/Pulmonary Atresia amenable to transcatheter balloon/stent dilation or coil occlusion.

Systemic Venous Stenosis & Thrombus

• Superior Vena Cava (SVC) obstruction (e.g., post-Mustard/Senning or heart transplantation) managed with stent implantation.
• Transcatheter thrombus management utilizes mechanical thrombectomy, balloon angioplasty, or acoustic pulse thrombolysis (EkoSonic Endovascular System).

Miscellaneous Interventions

• Coronary Artery Fistula: Transcatheter coil or device closure at distal orifice. Treatment of choice for symptomatic/large fistulas to prevent steal phenomenon or volume overload.
• Paravalvular Leaks: Device occlusion using vascular plugs (e.g., Amplatzer) under 3D TEE and fluoroscopic guidance. Success rates 70-90%.
• Balloon Atrial Septostomy (Rashkind): Creation of atrial communication in D-TGA or HLHS with restrictive atrial septum to improve mixing.

Hybrid Procedures

Hybrid therapies involve multidisciplinary collaboration between surgeons and interventional cardiologists, combining open and catheter-based techniques in a single setting to reduce CPB exposure and procedural trauma.

Stage 1 Palliation for HLHS

• Bilateral pulmonary artery banding, transcatheter stent insertion into ductus arteriosus, and balloon atrial septostomy.
• Avoids neonatal CPB exposure in high-risk patients with severe instability.
• Requires comprehensive Stage 2 reconstruction subsequently.

Perventricular VSD Closure

• Indicated for muscular VSDs in infants <5 kg where percutaneous delivery systems are too large for fragile peripheral vessels.
• Access achieved via subxiphoid or limited median sternotomy off-pump.
• Sheath introduced directly into RV free wall. Amplatzer muscular VSD device deployed under TEE guidance without fluoroscopy.

Intraoperative Stenting

• Stent placement in pulmonary arteries or veins during open-heart surgery.
• Allows deployment of adult-sized stents in small infants, avoiding complex patch angioplasty and limiting CPB duration.

Electrophysiology and Arrhythmia Management

Catheter Ablation

• Utilizes radiofrequency (resistive/conductive heating) or cryothermal (hemispherical “iceball”) energy.
• Cryothermal ablation preferred near AV node to eliminate permanent heart block risk.
• Electroanatomic mapping systems (magnetic/impedance-based) localize abnormal scar tissue, generate propagation maps, and minimize/eliminate fluoroscopy.
• Indicated for recurrent supraventricular tachycardia (SVT), atrioventricular nodal reentrant tachycardia (AVNRT), Wolff-Parkinson-White (WPW) syndrome, intra-atrial reentrant tachycardia (IART), and monomorphic ventricular tachycardia (VT).

Cardiac Rhythm Devices

• Pacemakers: Transvenous or epicardial systems for sinus node dysfunction or AV block. Leadless pacemakers available but limited in small pediatrics due to 23 French introducer sheath size.
• Implantable Cardioverter-Defibrillator (ICD): Class I indication for secondary prevention in survivors of sudden cardiac arrest or sustained VT.
• Cardiac Resynchronization Therapy (CRT): Biventricular pacing indicated for systemic ventricular dysfunction (EF < 35%) with wide QRS complex (>150 ms) to improve NYHA functional class and LV/RV function. May require epicardial leads due to complex CHD anatomy.