Effects of oral appliances and CPAP on the left ventricle and natriuretic peptides

Background In patients without cardiac disease, obstructive sleep apnea–hypopnea syndrome (OSAHS) is associated with systolic and diastolic dysfunction and left ventricular hypertrophy. Although continuous positive airway pressure (CPAP) therapy has been demonstrated to improve left ventricular structure and function in these patients, the effects of oral-appliance therapy on cardiac function are largely unknown. The aims of this study were to determine the left ventricular structure and function and natriuretic peptides in untreated OSAHS patients without cardiovascular disease, and to compare the effects of oral-appliance with CPAP therapy. Methods In 28 moderate to severe OSAHS patients echocardiography and measurements of concentrations of the amino-terminal fragment of pro-brain natriuretic peptide (NT-pro-BNP) were performed. Fifteen patients were randomized to oral-appliance and 13 to CPAP therapy. After 2 to 3 months of treatment echocardiography and NT-pro-BNP measurements were repeated. Results Of the 28 patients, 7 had left ventricular hypertrophy, 6 had left ventricular dilatation, and 3 had elevated NT-pro-BNP values. No significant improvements in echocardiographic outcomes were observed following treatment. The median NT-pro-BNP values improved significantly following oral-appliance therapy (52 pg/ml to 22 pg/ml) whereas not following CPAP therapy (31 pg/ml to 37 pg/ml). Conclusions This study demonstrates that 50% of patients with moderate to severe OSASH, without cardiovascular disease, have left ventricular hypertrophy, left ventricular dilatation or elevated natriuretic peptides. Significant changes in NT-pro-BNP values indicate an improvement of cardiac function following effective oral-appliance therapy.