Excerpt from Eisenmenger Syndrome

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Background

In 1897, Eisenmenger reported the case of a 32-year-old man who had showed exercise intolerance, cyanosis, heart failure, and hemoptysis prior to death. Autopsy showed a large ventricular septal defect (VSD) and overriding aorta. This was the first description of a link between a large congenital cardiac shunt defect and the development of pulmonary hypertension.

Pathophysiology

Eisenmenger syndrome occurs in patients with large congenital cardiac or surgically created extracardiac left-to-right shunts. These shunts initially cause increased pulmonary blood flow. Subsequently, usually before puberty, pulmonary vascular disease causes pulmonary hypertension, ultimately resulting in reversed or bidirectional shunt flow with variable degrees of cyanosis.

For more information, see Medscape CME activity, Eisenmenger's Syndrome: Pathophysiologic Insights and Pharmacologic Treatment Rationales.

Frequency

International

• The frequency of pulmonary hypertension and the subsequent development of reversed shunting vary depending on the specific heart defect and operative interventions.
• Approximately 50% of infants with a large, nonrestrictive VSD or patent ductus arteriosus (PDA) develop pulmonary hypertension by early childhood.
• Forty percent of patients with VSD or PDA and transposition of the great arteries develop pulmonary hypertension within the first year of life.
• The natural history of a large secundum atrial septal defect (ASD) differs in that the 10% of cases that progress to pulmonary hypertension do so more slowly and usually not until after the third decade of life.
• All patients with persistent truncus arteriosus and unrestricted pulmonary blood flow, and almost all patients with common atrioventricular canal, develop severe pulmonary hypertension by the second year of life.
• The frequency of pulmonary hypertension in surgically created systemic-to-pulmonary shunts varies depending on size and anatomy.
• Ten percent of those with a Blalock-Taussig anastomosis (subclavian artery to pulmonary artery) develop pulmonary hypertension compared to 30% of those with a Waterston (ascending aorta to pulmonary artery) or a Potts (descending aorta to pulmonary artery) shunt.

Mortality/Morbidity

• Exercise tolerance is severely impaired due to an inability to increase pulmonary blood flow, thereby limiting oxygen uptake. The systemic vascular bed is prone to vasodilation and subsequent systemic arterial hypotension, which can cause syncope.
• Long-term survival depends on the age at onset of pulmonary hypertension and the coexistence of additional adverse features, such as Down syndrome. Survival predominantly depends on right ventricular function. These patients usually do not survive beyond the second or third decade. The most frequent terminal event is a combination of hypoxemia and arrhythmia in the setting of rapid increases in pulmonary vascular resistance or decreases in systemic vascular resistance (SVR).
• The complications of chronic cyanotic heart disease affect multiple organ systems, including hematologic, skeletal, renal, and neurologic, causing significant morbidity and mortality.

Sex

No overall sex predilection has been reported.

Age

Eisenmenger syndrome usually develops before puberty but may develop in adolescence and early adulthood.

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