Left ventricular dysfunction, pulmonary hypertension, obesity, and sleep apnea

Area of Science:

• Cardiology
• Pulmonology
• Sleep Medicine

Background:

• Left ventricular dysfunction and pulmonary hypertension are common in congestive heart failure (CHF) patients.
• Obesity is a significant risk factor for both CHF and sleep apnea.
• The relationship between pulmonary hypertension and sleep apnea in CHF patients requires further investigation.

Purpose of the Study:

• To determine the frequency of central and obstructive sleep apnea in adult CHF patients with echocardiographic evidence of left ventricular dysfunction and pulmonary hypertension.
• To evaluate risk factors for pulmonary hypertension in this patient group.
• To explore the association between pulmonary hypertension severity and sleep apnea.

Main Methods:

• Retrospective chart review and prospective polysomnography in a small cohort of adult patients.
• Echocardiography for left ventricular dysfunction and pulmonary hypertension assessment (pulmonary artery systolic pressure >30 mm Hg).
• Exclusion of patients with lung disease; assessment included spirometry, pulse oximetry, rheumatologic evaluation, and sleep apnea evaluation (apnea-hypopnea index, AHI).

Main Results:

• All six completing subjects (AHI >= 20) had obstructive, central, or mixed sleep apnea.
• All subjects were obese with pulmonary artery systolic pressure >= 35 mm Hg.
• No daytime hypoxemia or collagen vascular disease was observed; none used appetite suppressants.

Conclusions:

• A strong association exists between pulmonary hypertension and obstructive or central sleep apnea in obese CHF patients.
• Pulmonary artery systolic pressure >= 35 mm Hg in ambulatory CHF patients may indicate an increased risk of sleep apnea.
• Further research is warranted to elucidate the causal mechanisms and clinical implications.