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ICR (Intracardiac Repair) - Complete Overview for the CTVS ICU

What Was Your Consultant Discussing?

• A residual RVOT gradient (measured by CW Doppler, modified Bernoulli: 4v²) that persists after VSD patch closure and infundibular resection
• Both ventricles can appear hyperdynamic in the immediate post-op period - the RV because it is still hypertrophied but now decompressed (afterload suddenly dropped), and the LV because it now receives full pulmonary venous return that was previously bypassed through the right-to-left shunt
• This hyperdynamic state is actually expected and reassuring in the first 24-48 hours if there are no residual lesions and cardiac output is adequate

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1. Basic Pathophysiology of ICR (TOF)

The Tetrad (Anatomic Basis)

Pathophysiological Flow

Obstruction at RVOT
     ↓
RV pressure rises → exceeds LV pressure
     ↓
Right-to-left shunt across VSD
     ↓
Desaturated blood enters aorta → Cyanosis
     ↓
Chronic hypoxia → Polycythemia, clubbing, tet spells
     ↓
LV is "underfilled" (pulmonary blood flow is reduced)

• Braunwald's Heart Disease, p. 886

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2. Surgical Steps of ICR for TOF

Access

• Median sternotomy + initiation of CPB (bicaval and aortic cannulation)
• Cardioplegic arrest
• Right atriotomy (preferred modern approach to avoid right ventriculotomy whenever possible)

Step 1 - VSD Closure

• Identify the large perimembranous/outlet VSD through the right atrium and tricuspid valve
• Close with a Dacron/Gore-Tex patch, securing it to avoid damage to the conduction system (AV node and His bundle run along the inferior rim of the VSD)
• Leaving a residual VSD causes L→R shunt post-op with volume overload

Step 2 - RVOT Relief (Infundibulectomy)

• Resection of hypertrophied infundibular muscle bundles (the obstructing bands in the subpulmonary region)
• If the pulmonary valve annulus is adequate: pulmonary valvotomy/commissurotomy only
• If annulus is too small: Transannular patch (TAP) - a patch is sutured across the pulmonary annulus + into the main PA, widening the RVOT. This reliably relieves obstruction but at the cost of pulmonary regurgitation (PR), which is the main long-term complication

Step 3 - Pulmonary Artery Augmentation (if needed)

• Branch PA stenosis may require patch augmentation
• If an anomalous LAD crosses the RVOT, a right ventricle-to-pulmonary artery conduit (RV-PA conduit) is used instead of a ventriculotomy or TAP

Optional - ASD Closure

• A coexistent ASD (or patent foramen ovale) is closed, unless intentionally left as a "pop-off" valve for restrictive RV physiology

Endpoint Criteria on the Table

• Residual RVOT gradient < 30-40 mmHg (RV/LV pressure ratio < 0.7)
• No significant residual VSD (by TEE, bubble study)
• SpO2 on room air > 95% on coming off bypass
• Braunwald's Heart Disease, p. 887

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3. Post-ICR ICU Management

Routine Post-Op Care

• Sedation/analgesia: Morphine + midazolam infusion; wean toward extubation
• Fluid: Crystalloid/colloid boluses <20 mL/kg in the first post-op night
• Inotropes: Milrinone (reduces RV afterload + positive inotropy) ± low-dose dopamine or dobutamine; wean as tolerated
• Pleural drains: Left in situ 24-48 hours due to pleural effusion risk

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Complication 1 - Restrictive RV Physiology

• Pre-op severe desaturation
• Transannular patch repair
• Long bypass/cross-clamp time
• Pre-op RV hypertrophy >5 mm wall thickness

• Low cardiac output syndrome (poor perfusion, hypotension, lactic acidosis)
• High CVP with hepatomegaly
• Positive fluid balance, ascites, pleural effusions
• Oliguria → may need peritoneal dialysis or CRRT
• Paradoxical improvement with spontaneous breathing (negative intrathoracic pressure augments RV filling and reduces RV afterload)

1. Maintain preload - higher filling pressures (CVP 12-15); these patients are preload-dependent
2. Milrinone - reduces PVR and RV afterload, improves relaxation
3. Avoid tachycardia - need adequate diastolic filling time; consider low-dose beta-blocker if rate is very high
4. Positive pressure ventilation (PPV) - use cautiously; increased intrathoracic pressure impairs RV filling. Consider early extubation when stable, as spontaneous breathing helps RV function
5. Inhaled nitric oxide (iNO) - reduces pulmonary vascular resistance, unloads the RV
6. Open the PFO/ASD - if a "pop-off" ASD was intentionally left open at surgery, this decompresses the right atrium at the cost of some cyanosis; accept SpO2 80-85% if cardiac output improves
7. Peritoneal dialysis - for fluid overload and renal support

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Complication 2 - Arrhythmias

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Complication 3 - Residual Lesions

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The RV/LV Hyperdynamic State (What Your Consultant Was Discussing)

• The RV is suddenly decompressed after years of pressure overload → it now ejects against a low-resistance pulmonary circuit → appears hyperdynamic on echo (high fractional area change, rapid ejection)
• The LV now receives full pulmonary venous return (previously reduced due to low pulmonary blood flow) → fills better → also appears hyperdynamic
• Doppler will show a residual gradient across the RVOT (mild to moderate is expected and accepted; >40 mmHg is concerning)
• The consultant was likely reviewing the echo and noting: "The RV and LV are both hyperdynamic - this is expected post-decompression. There's a residual gradient of X mmHg - we'll watch this."

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Summary at a Glance