Pre-Anaesthetic Considerations in Double Outlet Right Ventricle
Patients with double outlet right ventricle (DORV) require mandatory preoperative consultation with an adult congenital heart disease (ACHD) specialist before any elective non-cardiac surgery, as DORV is classified as an elevated-risk lesion with significant perioperative morbidity and mortality concerns 1.
Risk Stratification and Specialist Consultation
DORV falls into the elevated-risk category of congenital heart disease alongside other complex cyanotic lesions including pulmonary atresia, truncus arteriosus, and single-ventricle physiology 1. This classification mandates specialized preoperative assessment regardless of the planned surgical procedure.
The ACHD specialist consultation should specifically address 1:
- Cardiac anatomy clarification: Determine the exact anatomic variant of DORV, including the location of the ventricular septal defect (VSD) and presence/absence of pulmonary stenosis
- Prior surgical procedures and residua: Document all previous repairs, palliative procedures (such as Glenn shunts or Fontan completion), and identify any residual defects
- Current functional status: Assess exercise tolerance, NYHA functional class, and baseline oxygen saturation
- High-risk features: Screen for pulmonary arterial hypertension (PAH), significant arrhythmias, ventricular dysfunction, and end-organ damage
Critical Pathophysiologic Assessment
Shunt Direction and Cyanosis
The primary anesthetic risk in DORV involves aggravation of right-to-left shunting and worsening cyanosis 2. You must determine:
- Baseline oxygen saturation and degree of cyanosis
- Presence of pulmonary stenosis: DORV with pulmonary stenosis behaves like tetralogy of Fallot with cyanotic physiology, while DORV without stenosis causes congestive heart failure 3
- Shunt-dependent physiology: Whether systemic-pulmonary collaterals or surgical shunts (Blalock-Taussig) are present
Pulmonary Arterial Hypertension
PAH represents the most critical risk factor closely associated with severe complications and potential death 2. Preoperative evaluation must include:
- Echocardiographic estimation of pulmonary artery pressures
- Right ventricular function assessment
- Consideration of right heart catheterization if PAH severity is uncertain
Polycythemia and Coagulation
Chronic cyanosis leads to severe polycythemia (hemoglobin >20 g/dL, hematocrit >70%) with paradoxical coagulation dysfunction 4. Preoperatively assess:
- Complete blood count: Document hemoglobin and hematocrit levels
- Coagulation studies: PT, PTT, platelet count, and function
- Consider preoperative hemodilution if hematocrit exceeds 65-70% to reduce thromboembolism risk while correcting coagulopathy to prevent hemorrhage 4
Ventricular Function and Residual Lesions
For patients with prior surgical repair, evaluate 2:
- Right ventricular dysfunction: Chronic volume overload from pulmonary insufficiency or pressure overload from residual obstruction
- Left ventricular dysfunction: Often underappreciated in complex DORV
- Residual VSD: May serve as a "pop-off" valve for elevated right ventricular pressure
- Aortic root dilation: Associated with minimal but present dissection risk
- Arrhythmias: Both atrial and ventricular arrhythmias are common late complications
Hemodynamic Goals
The anesthetic plan must maintain specific hemodynamic targets based on the DORV physiology:
For Cyanotic DORV (with pulmonary stenosis):
- Avoid decreases in systemic vascular resistance (SVR): Hypotension worsens right-to-left shunting
- Avoid increases in pulmonary vascular resistance (PVR): Hypoxia, hypercarbia, acidosis, hypothermia, and pain all increase PVR
- Maintain preload: Adequate right ventricular filling is essential
- Maintain heart rate and rhythm: Avoid extreme tachycardia or bradycardia
For Acyanotic DORV (without pulmonary stenosis):
- Manage as left-to-right shunt physiology: Avoid increases in pulmonary blood flow
- Monitor for heart failure: Volume overload is the primary concern
Anesthetic Technique Selection
Based on available case reports, both regional and general anesthesia can be safely employed when carefully managed 3, 5:
Regional Anesthesia Considerations:
- Carefully titrated combined spinal-epidural has been successfully used 5
- Avoid rapid sympathectomy and SVR drops
- Contraindicated if coagulopathy from polycythemia is uncorrected
General Anesthesia Considerations:
- Total intravenous anesthesia (TIVA) with dexmedetomidine and fentanyl provides hemodynamic stability and neuroprotection 6, 7
- Ketamine maintains SVR and is suitable for induction 6
- Avoid agents causing significant myocardial depression or vasodilation
- Maintain spontaneous ventilation when feasible for short procedures 7
- Positive pressure ventilation may decrease venous return and worsen right-to-left shunting
Common Pitfalls to Avoid
- Proceeding without ACHD specialist input: This is a guideline-mandated requirement, not optional 1
- Assuming all DORV patients are identical: Physiology varies dramatically based on VSD location and presence of pulmonary stenosis 3
- Ignoring polycythemia: Hematocrit >65% requires preoperative hemodilution 4
- Underestimating PAH risk: PAH is the leading cause of perioperative mortality in cyanotic heart disease 2
- Rapid anesthetic induction: Gradual titration prevents catastrophic hemodynamic collapse
- Inadequate monitoring: Invasive arterial monitoring and transesophageal echocardiography should be strongly considered for moderate-to-high risk procedures
Preoperative Optimization Checklist
- ACHD cardiology consultation completed
- Current echocardiogram reviewed (within 6-12 months)
- Arrhythmia screening with ECG, consider Holter if symptomatic
- Hematocrit optimization if >65%
- Coagulation profile normalized
- Baseline oxygen saturation documented
- Pulmonary artery pressure estimated
- Ventricular function quantified
- Endocarditis prophylaxis planned per guidelines
- Coordination with cardiac anesthesia team for complex cases