Closed Heart Surgery - Detailed Clinical Note

(15 Marks | BPT Clinical Cardiology | MGR University)

Definition

Historical Background

Classification of Closed Heart Procedures

A. Corrective (Definitive) Closed-Heart Procedures

1. PDA (Patent Ductus Arteriosus) Ligation
2. Repair of Coarctation of the Aorta
3. Closed Mitral Valvotomy / Commissurotomy

B. Non-Corrective (Palliative) Closed-Heart Procedures

1. Pulmonary Artery Banding - for large VSD / excessive pulmonary blood flow
2. Systemic-to-Pulmonary Artery Shunts (Blalock-Taussig shunt, Potts shunt, Waterston shunt)

1. Closed Mitral Valvotomy (CMV) / Closed Mitral Commissurotomy (CMC)

Indication

• Symptomatic rheumatic mitral stenosis (NYHA Class II-IV)
• Mitral valve area < 1.5 cm² in a normal-sized adult (or < 1 cm²/m² BSA)
• Pliable, non-calcified leaflets with minimal subvalvular fusion
• No left atrial thrombus; MR ≤ 2+/4+

Surgical Technique

1. Approach: Left posterolateral thoracotomy (4th or 5th intercostal space)
2. Pericardiotomy: Pericardium is incised to expose the left atrium and left ventricle
3. Purse-string suture: Placed on the left atrial appendage and on the left ventricular apex
4. Digital exploration: Surgeon's index finger introduced through the left atrial appendage to assess the valve (palpate commissural fusion, subvalvular thickening, presence of thrombus)
5. Commissurotomy: A mechanical dilator (Tubbs dilator or Brock's dilator) is introduced through the left ventricular apex and advanced under digital guidance to the mitral orifice; the dilator is opened to split the fused commissures
6. Assessment: The surgeon assesses the adequacy of commissurotomy by finger palpation; auscultation for diastolic murmur reduction
7. Closure: Purse-string sutures tightened; routine chest closure

Advantages of CMV

• No cardiopulmonary bypass required
• Lower morbidity and shorter operating time
• Suitable for resource-limited settings (historically important in India)

Disadvantages / Limitations

• "Blind" procedure - no direct visualization
• Cannot address subvalvular disease adequately
• Cannot remove atrial thrombus
• Risk of inducing mitral regurgitation
• Largely replaced by Percutaneous Balloon Mitral Commissurotomy (PBMC) and open surgical commissurotomy in modern practice

Contraindications to CMV

• Significant mitral regurgitation (> Grade 2)
• Left atrial thrombus
• Heavily calcified valve
• Combined aortic + mitral disease
• Previous commissurotomy with restenosis

Results

• Event-free survival in younger patients (< 45 years) with pliable valves: 80-90% over 3-7 years (Harrison's Principles, 22e)
• Operative mortality: approximately 2% for surgical commissurotomy

2. Patent Ductus Arteriosus (PDA) Ligation

Pathophysiology

Indication for Surgery

• Symptomatic PDA not responding to medical treatment (indomethacin + fluid restriction in premature infants)
• Large PDA causing congestive heart failure
• Prevention of Eisenmenger syndrome

Surgical Technique

1. Approach: Left thoracotomy (3rd intercostal space) OR video-assisted thoracoscopic surgery (VATS) - increasingly common
2. Exposure: Pleura is opened; aortic arch and descending aorta identified; left recurrent laryngeal nerve carefully protected
3. Ligation: The ductus is isolated between ligatures and divided, OR clipped with surgical clips; in premature infants, simple ligation without division is performed
4. Verification: Pulse oximeter on lower extremity detects any inadvertent ligation of the descending aorta

Complications

• Inadvertent ligation of the left pulmonary artery or descending aorta
• Recurrent laryngeal nerve damage (left-sided hoarseness)
• Excessive bleeding from PDA disruption
• Post-ligation: worsening pulmonary compliance in premature infants; acute increase in left ventricular afterload

3. Repair of Coarctation of the Aorta

Definition

Surgical Techniques (all without CPB)

Intraoperative Monitoring

• Bilateral radial arterial lines (right arm = pre-ductal; left arm shows subclavian sacrifice effect)
• Femoral arterial line = post-ductal pressure
• NIRS (near-infrared spectroscopy) monitors spinal cord perfusion
• Cross-clamp time should be minimized to prevent paraplegia from spinal cord ischemia

Complications

• Paraplegia (from spinal cord ischemia during aortic cross-clamping)
• Paradoxical hypertension post-repair (mesenteric arteritis)
• Recoarctation (especially after subclavian flap in neonates as they grow)
• Bleeding, chylothorax

4. Systemic-to-Pulmonary Artery Shunts (Palliative)

Purpose

• Increases pulmonary blood flow in duct-dependent circulation
• Allows the child to grow before definitive repair (e.g., total correction of TOF)
• Reduces hypoxic spells (Tet spells)

5. Pulmonary Artery Banding (PAB)

Indication

• Large VSD or other causes of excessive pulmonary blood flow (Qp:Qs >> 1) when complete repair cannot be performed (premature neonate, complex anatomy)
• Preparation for biventricular repair or univentricular palliation

Procedure

• Left thoracotomy or median sternotomy
• A tape or band placed around the main pulmonary artery and tightened until:
  • Distal PA pressure = 25-50% of systemic pressure
  • Qp/Qs approaches 1:1
  • Acceptable oxygen saturation maintained
• The band is secured with sutures to prevent migration

Complications

• Over-tightening: cyanosis, right ventricular hypertrophy
• Under-tightening: persistent pulmonary overcirculation
• Band migration
• Pulmonary artery distortion (makes future corrective surgery difficult)

Key Differences: Closed vs. Open Heart Surgery

Anesthetic Considerations in Closed Heart Surgery

1. No CPB - arterial and central venous access still essential
2. Intra-arterial monitoring mandatory (site depends on procedure - avoid right radial for BT shunt, avoid left radial for subclavian flap coarctation repair)
3. NIRS monitoring for cerebral and somatic (spinal cord) perfusion
4. Pulse oximetry on both upper and lower extremities
5. One-lung ventilation may be required for thoracoscopic PDA ligation
6. Anticipate hemodynamic shifts from aortic cross-clamping (coarctation) or shunt manipulation

Summary Points for Exam

• Closed heart surgery = no CPB, beating heart, through thoracotomy
• CMV was the first widespread cardiac operation; replaced by PBMC and open surgery
• PDA ligation is corrective; commonest closed heart procedure in neonates
• Coarctation repair uses aortic cross-clamping; paraplegia is a feared complication
• BT shunt is palliative for cyanotic CHD to increase pulmonary blood flow
• PA banding is palliative to reduce pulmonary overcirculation
• All procedures avoid CPB, thus avoiding pump-related complications (hemolysis, coagulopathy, systemic inflammatory response)
• Early corrective repair in infancy has significantly reduced the need for palliative closed-heart operations (Miller's Anesthesia, 10e)

• Sabiston Textbook of Surgery, 7e - History of Heart Valve Surgery, pp. 2527-2530
• Harrison's Principles of Internal Medicine, 22e - Mitral Commissurotomy, Chapter 274
• Miller's Anesthesia, 10e - Anesthesia for Closed-Heart Operations, pp. 10851-10857
• Fuster & Hurst's The Heart, 15e - Mitral Valve Disease