Prospective Evaluation of New Metrics to Assess Cardiovascular Remodeling in Obstructive Sleep Apnea

Interventricular septal thickness will be assessed via 2D-guided M-mode echocardiographic measurements in the parasternal long-axis view.

This novel metric is calculated by determining the total area under the respiratory event-related desaturation curve, which can be obtained from a polysomnography (PSG). It has been shown to be a good predictor of cardiovascular disease mortality, but has not yet been established in daily practice.

ΔHR is defined as the difference between the maximum pulse rate after airway opening, i.e. during a subject-specific search window, and an event-related minimum pulse rate, i.e. minimum pulse rate during respiratory events. ΔHR will be calculated from a photoplethysmography (PPG), a signal derived from a finger pulse oximeter, which is part of the standard clinical PSG set-up.

PWADs can be calculated from photoplethysmography (PPG), a signal derived from a finger pulse oximeter, which is part of the standard clinical PSG set-up.

Heart rate variability will be calculated from ECG-derived RR intervals obtained during the sleep study.

Left ventricular ejection fraction will be assessed via 2D-guided M-mode echocardiographic measurements in the parasternal long-axis view.

Left ventricular mass will be assessed via 2D-guided M-mode echocardiographic measurements in the parasternal long-axis view.

24-hour ambulatory blood pressure will be measured using ambulatory blood pressure monitoring (ABPM).

Left ventricular systolic and diastolic function will be evaluated using 2D echocardiography. Systolic function will be quantified by left ventricular ejection fraction calculated using the Simpson biplane method. Diastolic function will be assessed using pulsed wave tissue Doppler imaging at the septal and lateral mitral annulus, mitral inflow velocities (E/A ratio), the E/e' ratio and left atrial volume index.

The apnea-hypopnea Index (AHI), defined as the number of apneas (cessations in breathing) and hypopneas (reductions in airflow) per hour of sleep measured during a polysomnography, will be assessed. OSA is diagnosed when the AHI is at least 5/h. The AHI classifies OSA as mild with AHI ranging from 5 to 14.9 events per hour, moderate with AHI ranging from 15 to 29.9 events per hour and severe when 30 or higher events per hour.

The oxygen desaturation index (ODI) represents the number of oxygen desaturation events per hour of sleep, typically defined as a ≥3% or ≥4% drop in arterial oxygen saturation from baseline.

Average hours of therapy use per night and the number of nights per week can be retrieved from data stored in the device.

Visual analogue scale for snoring, from 0 to 10: 0 represents no snoring, 1-3 represents minimally annoying, 4-6 represents moderately annoying, 7-9 represents annoying, and 10 represents extremely annoying.

Daytime sleepiness measured using the Epworth sleepiness scale (ESS), which is a self-administered questionnaire that assesses the likelihood of falling asleep in various settings and situations in daily life.The questionnaire consists of eight items scored from 0 to 3, resulting in a total score ranging from 0 to 24. The lowest score (zero) suggests that the described incident is absent and the highest score (three) suggests the presence of this event.

Fatigue was assessed using the checklist individual strength, a 20-item questionnaire with each item scored on a 7-point Likert scale, resulting in total scores ranging from 20 to 140. Higher scores indicate greater fatigue severity.