CardiologyTier 2Disease (DEADMAN)

Congenital heart disease - Eisenmenger syndrome

Description

Reversal of a long-standing left-to-right shunt into right-to-left
Sequence:
- Chronic inc pulmonary blood flow
- -> endothelial dysfunction + pulmonary vascular remodelling
- -> inc PVR until it equals or exceeds SVR
- -> shunt reverses -> cyanosis
End-stage of unrepaired large shunts - VSD, ASD, PDA, AVSD
- Also palliative shunts: Blalock-Taussig, Potts, Waterston
*Defect closure is contraindicated* - the shunt is now the RV's pressure release valve

Vascular

High-flow, high-pressure pulmonary circulation -> shear injury
- -> medial hypertrophy, intimal fibrosis, plexiform lesions
- -> fixed, irreversible inc PVR

Consequences of chronic hypoxaemia

inc EPO -> secondary erythrocytosis
- Compensatory, not polycythaemia vera - do not venesect reflexively
Iron deficiency common -> microcytes -> worse hyperviscosity at a lower haematocrit
Abnormal haemostasis - both bleeding and thrombosis
inc urate -> gout; inc bilirubin turnover -> pigment gallstones
Right-to-left shunt -> paradoxical embolism, cerebral abscess

Clinical

Central cyanosis + clubbing, plethora
PHT signs - raised JVP, RV heave, loud P2, PR and TR murmurs
Shunt murmurs quieten and disappear as pressures equalise
Sternotomy or thoracotomy scars
Differential cyanosis - feet more cyanosed and clubbed than hands = reversed PDA
- Reverse differential cyanosis (hands worse) = TGA with PDA

Investigations

FBC (erythrocytosis), iron studies, urate, LFTs, coagulation
ECG: RVH, right-axis deviation, RBBB
CXR: enlarged central pulmonary arteries with peripheral pruning, RV enlargement
TTE: underlying lesion, shunt direction, RV function
- RV failure marks poor prognosis
Cath: PVR, shunt quantification, reversibility

First principle

Erythrocytosis and hyperviscosity

Do not venesect routinely
- Only for symptomatic hyperviscosity, with volume replacement
Correct iron deficiency - iron-deficient microcytes worsen viscosity
Avoid dehydration

PAH-targeted therapy

Avoid

Definitive

Survival better than idiopathic PAH - the shunt decompresses the RV - but far below the general population
Causes of death: sudden cardiac death, heart failure, haemoptysis, stroke, perioperative

Complications

Monitor

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