Sleep-disordered Breathing in Eisenmenger Syndrome

Congenital heart defects (CHD) occur in approximately 1% of all live births. Around 5% of adults with CHD develop pulmonary arterial hypertension (PAH), with 25-50% of these patients exhibiting the most serious form, Eisenmenger syndrome. Eisenmenger syndrome is caused by a systemic-to-pulmonary shunt, which eventually leads to high pulmonary vascular resistance with right-to-left or bi-directional shunt. Right-to-left shunting reduces the systemic arterial oxygen capacity and consequently causes cyanosis, which may result in hypoxic tissue damage and multi-organ disease.

The natural history of Eisenmenger syndrome (ES) is generally poor compared to the general population with the latest reported actual survival rates of 94%, 74% and 52% at 40, 50 and 60 years of age, respectively. Until recently conventional symptomatic treatment with diuretics, digitalis, antiarrhythmic, anticoagulants, iron supplement, oxygen therapy, and ultimately heart-lung transplantation were the only options. Most patients die from progressive cardiovascular disease and heart failure, sudden heart death or haemoptysis.

However, the introduction of advanced therapy (AT) has improved symptoms and may also have changed to prognosis of these patients. Thus, newer studies have shown beneficial effect of treatment with advanced therapy including endothelin receptor antagonists, phosphodiesterase-5 inhibitors, and prostanoids. These pulmonary vasodilators are now recognized as targeted therapy in Eisenmenger syndrome.

Sleep-disordered breathing (SDB) with predominantly obstructive or central sleep apnoea (OSA/CSA) with Cheyne-Stokes respiration (CSR) is shown to be a common comorbidity in patients with heart failure (HF), as it is present in at least 50 % of these patients. In the general Danish population the estimated prevalence is 3-18% in men and 5-7% in women.

Studies in HF patients also suggest an increased rate of central sleep apnoea (CSA) versus obstructive sleep apnoea (OSA) compared to the general population. SDB may promote the progression of chronic heart failure (HF) and is independently associated with a decreased survival rate.