Congenital Heart Disease in Adults

Adult CHD Basics - Grown-Up Heart Puzzles

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Shunt Lesions (Acyanotic) - Flow Follies & Fixes

Acyanotic lesions: L→R shunts (ASD, VSD, PDA), no initial cyanosis.

• Pathophysiology: ↑ Pulmonary Blood Flow (PBF), $Q_p/Q_s > 1$ → Pulmonary Hypertension (PHT) → Eisenmenger syndrome (shunt reversal, R→L, cyanosis).
  • ASD: RV volume overload. Risk of paradoxical embolism.
  • VSD/PDA: LV volume overload.
• Anesthetic Goals (Maintain Shunt Balance):
  • Maintain SVR (avoid ↓SVR as it ↑ L→R shunt).
  • Control PVR (avoid factors ↑PVR: hypoxia, hypercarbia, acidosis, high airway pressures).
  • Avoid air embolism (esp. with septal defects).
  • SBE prophylaxis often indicated.

⭐ In left-to-right shunts (ASD, VSD, PDA), avoid significant drops in Systemic Vascular Resistance (SVR) as this can worsen the shunt; maintain or increase Pulmonary Vascular Resistance (PVR) relative to SVR.

Obstructive & Cyanotic CHD - Tricky Tunnels & Blue Hues

• Obstructive Lesions:
  • CoA: Aortic narrowing. UE HTN, LE ↓BP. Goal: Maintain SVR, cord perfusion.
  • Congenital AS: Often bicuspid. Goal: "Slow, full, tight" (NSR, SVR, preload).
  • PS: RVOTO. Goal: Maintain preload, contractility; avoid ↑ PVR.
• Cyanotic Lesions (R→L Shunts):
  • TOF: 📌 PROVe (Pulmonary Stenosis, RVH, Overriding aorta, VSD). "Tet spells".

    ⭐ For Tetralogy of Fallot (TOF) patients, anesthetic management aims to increase SVR (e.g., phenylephrine) and decrease PVR (e.g., oxygen, avoid acidosis) to reduce right-to-left shunting, especially during 'tet spells'.

  • TGA: Discordant ventricles/arteries. Mixing needed (ASD/PDA). Goal: Balance PVR/SVR.
  • Tricuspid Atresia: Hypoplastic RV. ASD & VSD/PDA dependent.
  • Eisenmenger Syndrome: Severe PHTN → R→L shunt. Goal: SVR > PVR. Avoid ↓ SVR.

Anesthetic Strategies & Safeguards - Navigating the Maze

• Pre-op: Assess shunt, PVR, ventricular function. Multidisciplinary approach.
• Intra-op Goals:
  • Monitoring: Standard + Arterial line, CVP; TEE/PAC for complex cases.
  • Maintain baseline shunt.
  • Balance PVR/SVR:
    • L-R Shunt: Avoid ↑SVR, ↓PVR.
    • R-L Shunt: Avoid ↓SVR, ↑PVR (📌 "Right Resist, Left Less").
  • Prevent air embolism (especially R-L shunts; use air filters).
• Key Safeguards:
  • Avoid hypoxia, hypercarbia, acidosis (all ↑PVR).

⭐ Antibiotic prophylaxis for infective endocarditis is indicated for all prosthetic valve repairs, previous IE, unrepaired cyanotic CHD, and repaired CHD with residual defects at or adjacent to prosthetic material for 6 months post-procedure.

High‑Yield Points - ⚡ Biggest Takeaways

• Eisenmenger syndrome: Contraindicates spinal/epidural anesthesia due to risk of ↓SVR and shunt reversal.
• Fontan circulation: Relies on passive pulmonary blood flow; maintain adequate preload and low PVR.
• Tetralogy of Fallot (TOF): Patients are prone to hypercyanotic "tet" spells; avoid ↓SVR and ↑PVR.
• Atrial Septal Defect (ASD): Carries risk of paradoxical embolism; meticulous de-airing of IV lines is crucial.
• Coarctation of Aorta: Presents with upper limb hypertension and lower limb hypotension; monitor both.
• Infective endocarditis prophylaxis: Essential for high-risk CHD patients undergoing invasive procedures.