Eisenmenger Syndrome

The Eisenmenger Syndrome is a late-stage, irreversible complication of untreated congenital heart defects, characterized by advanced pulmonary hypertension and reversal of the left-to-right shunt into a right-to-left shunt. This condition leads to cyanosis, chronic hypoxemia, and multisystem complications.
The incidence of Eisenmenger Syndrome has significantly decreased in developed countries due to early surgical correction of congenital heart defects. However, it remains a major condition in countries with limited access to pediatric cardiology care.

Anatomy and Pathophysiology

Eisenmenger syndrome develops in patients with congenital heart defects that create a persistent left-to-right shunt, such as:

• Ventricular septal defect (VSD)
• Atrial septal defect (ASD)
• Patent ductus arteriosus (PDA)
• Persistent truncus arteriosus

Initially, the left-to-right shunt causes pulmonary volume overload, leading to progressive vascular remodeling and intimal hyperplasia in the pulmonary arteries. This process results in an irreversible increase in pulmonary vascular resistance, which eventually exceeds systemic pressure, reversing the shunt into a right-to-left direction. As a consequence, deoxygenated blood bypasses the pulmonary circulation and mixes with arterial blood, leading to cyanosis and systemic hypoxemia.

Signs and Symptoms

Patients with Eisenmenger Syndrome present with a progressive clinical picture, including:

• Cyanosis: bluish discoloration of the mucosa and extremities.
• Digital clubbing: thickening of the distal phalanges ("drumstick fingers").
• Dyspnea: progressive respiratory difficulty, worsened by exertion.
• Fatigue: reduced exercise tolerance.
• Palpitations: sensation of irregular heartbeat.
• Syncope: episodes of loss of consciousness due to reduced cerebral perfusion.
• Secondary polycythemia: compensatory response to chronic hypoxemia.
• Hemoptysis: risk of spontaneous pulmonary bleeding.

Diagnosis

The diagnosis of Eisenmenger Syndrome is based on:

• History and physical examination: detection of cyanosis, clubbing, and respiratory symptoms.
• Echocardiography: evaluation of congenital heart defects and pulmonary hypertension.
• Cardiac catheterization: direct measurement of pulmonary pressures and shunt direction.
• Blood tests: reveal polycythemia and coagulation abnormalities.
• ECG: signs of right ventricular overload.
• Chest X-ray: shows enlargement of the pulmonary artery.

Treatment

Eisenmenger Syndrome is an irreversible condition; therefore, treatment focuses on symptom control and prevention of complications.

• Pulmonary hypertension medications: phosphodiesterase-5 inhibitors (sildenafil), endothelin receptor antagonists (bosentan).
• Oxygen therapy: in cases of severe hypoxemia.
• Controlled phlebotomy: in cases of symptomatic hyperviscosity.
• Heart-lung transplantation: the only curative therapy for advanced cases.

Prognosis

The prognosis of Eisenmenger Syndrome depends on clinical management and associated complications. Survival can exceed 30-40 years, but patients remain at risk for heart failure, fatal hemoptysis, and arrhythmias.

References

References
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