Effect of Obstructive Sleep Apnea and Positive Airway Pressure Therapy on Cardiac Remodeling as Assessed by Cardiac Biomarker and Magnetic Resonance Imaging in Nonobese and Obese Adults

Abstract

It is unknown whether obesity modifies the effect of obstructive sleep apnea (OSA) and positive airway pressure (PAP) therapy on cardiac remodeling and NT-proBNP (N-terminal pro-B-type natriuretic peptide) levels. We compared NT-proBNP and cardiac magnetic resonance imaging in adults without OSA (n=56) and nonobese (n=73; body mass index <30 kg/m2) and obese (n=136; body mass index ≥30 kg/m2) adults with OSA. We also investigated these traits in nonobese (n=45) and obese (n=78) participants with OSA adherent to 4 months of PAP treatment. At baseline, left ventricular mass to end-diastolic volume ratio, a measure of left ventricular concentricity, was greater in both nonobese and obese participants with OSA compared with those without OSA. Participants with OSA and obesity exhibited reduced phasic right atrial function. No significant differences in baseline NT-proBNP were observed across groups. The effect of PAP treatment on NT-proBNP and left atrial volume index was significantly modified by obesity. In nonobese participants, PAP therapy was associated with a decrease in NT-proBNP (P<0.0001) without a change in left atrial volume index, whereas in obese participants, PAP was associated with an increase in left atrial volume index (P=0.006) without a change in NT-proBNP. OSA was associated with left ventricular concentric remodeling independent of obesity and right atrial dysfunction in participants who were obese. PAP treatment was associated with reduced NT-proBNP in nonobese participants with OSA, but left atrial enlargement in obese participants with OSA, suggesting that PAP-induced reduction in BNP release (which is known to occur during obstructive apnea episodes) may lead to volume retention in obese participants with OSA. Registration: URL: https://www.clinicaltrials.gov; Unique identifier: NCT01578031.

Keywords: magnetic resonance imaging; natriuretic peptide, brain; obesity; sleep apnea, obstructive.

Figures

Figure 1:

Flow chart of participants utilized in the present study.

Figure 2:

Association between NT-proBNP and continuous BMI in participants without and with OSA. NT-proBNP was negatively associated with continuous BMI in participants without OSA, but was not significantly related to BMI in participants with OSA, adjusting for age, sex, race, clinical site, and baseline 24-hour systolic and diastolic blood pressure and use of alcohol, beta blockers, angiotensin-converting enzyme inhibitors or angiotensin receptor blockers, calcium-channel blockers, statins, and diabetes medications.

Figure 3:

NT-proBNP values before and following PAP treatment in non-obese and obese participants with OSA adherent to PAP. Natural log transformed NT-proBNP was significantly reduced only in non-obese participants with OSA, but not significantly changed in obese participants with OSA. LA volume index was significantly increased only in obese participants with OSA, but not significantly changed in non-obese participants with OSA. P-value was based on fully adjusted model, adjusting for age, sex, race, clinical site, AHI, systolic and diastolic blood pressure and use of alcohol, beta blockers, angiotensin-converting enzyme inhibitors or angiotensin receptor blockers, calcium-channel blockers, statins, and diabetes medications at baseline, as well as change of 24-hour systolic and diastolic blood pressure following PAP treatment.