December 30, 2022Open Access

Subclinical and latent cardiac dysfunction in obstructive sleep apnea and effectiveness of continuous positive airway pressure

Q: What is the clinical evidence from this study?

Study design: Cohort. Population: Obstructive sleep apnea (n=275). Intervention: Continuous positive airway pressure (CPAP) vs. Baseline. Primary outcome: Global longitudinal strain (GLS) (p=0.004).

TKTakahiro KandaHamamatsu University Hospital KTKei TawaraharaTakamatsu Red Cross Hospital HKHaruta KatoHamamatsu University School of Medicine

Key Result

Continuous positive airway pressure therapy significantly improved global longitudinal strain from -18.1% to -19.0% in patients with moderate to severe obstructive sleep apnea.

Study Design

Type

Cohort (n=275)

Multicenter

Structured PICO

Does continuous positive airway pressure (CPAP) improve global longitudinal strain in patients with moderate to severe obstructive sleep apnea at risk for heart failure?

Population

275 consecutive patients with polysomnographic obstructive sleep apnea (AHI >5) at risk for heart failure but who had not yet developed structural heart changes.

Intervention

Continuous positive airway pressure (CPAP) therapy for a median period of 283 days.

Comparator

Pre-CPAP baseline (for treatment effect) and mild OSA (for baseline comparison).

Outcome

Global longitudinal strain (GLS) calculated by two-dimensional speckle tracking analysis.surrogate

CPAP therapy significantly improves subclinical left ventricular dysfunction, as measured by global longitudinal strain, in patients with moderate to severe obstructive sleep apnea at risk for heart failure.

Main Result

Absolute Event Rate: -19% vs -18.1%

p-value: p=0.004

Limitations

Retrospective observational study with many patients excluded due to insufficient echocardiographic images for GLS analysis.
Patients taking antihypertensive drugs at the first visit were defined as hypertensive, potentially misclassifying subclinical hypertensive patients.
CPAP adherence was only evaluated based on the one month before follow-up echocardiography, not throughout the entire therapy period.

Abstract

PURPOSE: Obstructive sleep apnea (OSA) is associated with various cardiovascular disorders. This study aimed to investigate the effects of OSA on left ventricular (LV) function in patients with OSA who were at risk for heart failure but who had not yet developed structural heart changes. The study also sought to determine the effects of continuous positive airway pressure (CPAP) in these patients. METHODS: In a retrospective study, consecutive patients with polysomnographic OSA (apnea-hypopnea index AHI >5) were categorized into mild (AHI < 15), moderate (15 ≤ AHI < 30), and severe OSA (AHI ≥ 30) groups. The subjects were patients with OSA and at risk for heart failure who had not yet developed structural heart changes. All study participants underwent echocardiography and two-dimensional speckle tracking analysis, and their global longitudinal strain (GLS) was calculated. RESULTS: Of 275 patients, there were 31 with mild, 92 with moderate, and 152 with severe OSA. Of patients with moderate to severe OSA (AHI ≥ 20), 206 started CPAP and 92 patients underwent follow-up echocardiogram and speckle tracking echo analysis (median period of CPAP use: 283 days 258 to 391). GLS was significantly reduced in patients with moderate and severe OSA compared with mild OSA (-17.8±3.1 vs. -18.0±2.6 vs. -19.3±2.8%, p=0.038). The proportion of patients with GLS ≥ -18% was significantly higher among the patients with moderate to severe OSA than among those with mild OSA. GLS improved after CPAP therapy in patients with moderate to severe OSA (GLS: -18.1±2.7% to -19.0±2.8%, p=0.004). Significant improvement in GLS was confirmed, particularly among patients with good CPAP adherence. CONCLUSION: Moderate to severe OSA is associated with LV dysfunction and can be significantly improved by CPAP therapy.

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