Key points

• Sleep-Related Breathing Disorders, such as obstructive sleep apnoea (OSA), are highly prevalent and they significantly impact cardiovascular, metabolic, and mental health.
• Sleep-Related Breathing Disorders particularly obstructive sleep apnoea (OSA), are closely linked to cardiovascular issues, including hypertension, pulmonary hypertension, heart failure, atrial fibrillation, and coronary artery disease. OSA increases the risk of developing hypertension and negatively affects cardiovascular outcomes.
• Cardiology societies, such as the American Heart Association and European Society of Cardiology, increasingly emphasize the importance of screening for sleep disorders in various cardiovascular conditions, such as heart failure, atrial fibrillation, and resistant hypertension. The focus is on recognizing and addressing obstructive sleep apnea (OSA).
• Treating sleep-related disorders like OSA can have an impact on some cardiovascular conditions. Similarly, untreated OSA can hinder the effectiveness of treatments or even worsen some conditions.
• Brizzy is the perfect screening tool for cardiologists: a simple screening tool designed to make the screening process for sleep-related breathing disorders more accessible and precise for cardiologists. Brizzy is easy to use at home, highly accurate, and equipped with clinical decision-support tools to assist cardiologists in patient care.

Sleep-related breathing disorders are common, with up to 38% of the general population affected and 1 in 5 patients facing moderate to severe Obstructive Sleep Apnea (OSA) . Understanding the prevalence of SBDs and their implications on cardiovascular health is crucial. These disorders, particularly obstructive sleep apnea, disrupt a patient's sleep, leading to excessive daytime sleepiness, fatigue, mood disturbances, and cognitive decline. Identifying and addressing SBDs can significantly enhance a patient's quality of life. Beyond the obvious impact on sleep, SBDs extend their influence on cardiovascular, metabolic, and mental health(2-5).

Understanding the connection between sleep-related breathing disorders (SBDs) and the cardiovascular system is essential for providing comprehensive patient care. Indeed, studies have shown a high correlation between SBDs and the cardiovascular system(6). By identifying and managing SBDs, we can help reduce their cardiovascular consequences.

(Resistant) Hypertension

Research has shown that individuals with untreated OSA are at a heightened risk of developing hypertension(7). This relationship is particularly true in resistant hypertension(8) with one study showing that 83% of patients with resistant hypertension also had sleep apnoea(9).

Pulmonary hypertension

Pulmonary hypertension and sleep apnoea are also connected, with the latter thought to play a role in the physiopathology of pulmonary hypertension. About 20% of patients with OSA have class III pulmonary hypertension(10).

Heart Failure

OSA is common in patients with heart failure(6). Critically, OSA puts additional strain on the heart, reducing its ability to pump blood effectively and increasing morbidity and mortality(11).

Atrial fibrillation and other arrhythmias

Sleep-related breathing disorders can lead to arrhythmias. The clearest example is atrial fibrillation, as patients with OSA are four times more likely to develop atrial fibrillation(12).

Coronary artery disease and stroke

OSA is strongly associated with an increased risk of coronary artery disease, heart attacks, and strokes. The repeated episodes of oxygen deprivation and increased stress on the heart during sleep can contribute to the development and progression of these conditions6.

Cardiology Guidelines: An increasing focus on sleep

In recent years, statements and guidelines issued by cardiology societies have shown an increased focus on sleep. Notably, the American Heart Association (AHA) published a statement in 2021 on the link between sleep disorders – sleep apnoea in particular, and cardiovascular health. In this statement, the association said:

Similarly, the European Society of Cardiology (ESC) has included sleep in its recent guidelines for several conditions such as heart failure, atrial fibrillation, or resistant hypertension. We will quickly discuss what the ESC recommends, but the general trend is clear: sleep disorders are frequently comorbid with cardiovascular conditions and impact each other significantly. Therefore, evaluating patients for sleep disorders, sleep apnoea at least, is necessary for the comprehensive management of their cardiovascular health.

ESC: Heart Failure (14)

Over a third of patients with heart failure suffer from sleep-disordered breathing, and this is particularly true in acute heart failure. Both central sleep apnea (CSA), obstructive sleep apnea (OSA), and a mixed pattern of both can be found and are associated with a poorer prognosis. Moreover, OSA also increases the risk of incident of heart failure in men.

Given the high frequency and the impact on prognosis, patients with heart failure can be investigated for sleep apnea. Questionnaires can be useful, but home monitoring can identify of sleep apnea and distinguish between the types.

ESC: Atrial Fibrillation (15)

Obstructive sleep apnea (OSA) is highly prevalent in patients with atrial fibrillation, with a prospective study finding a 50% prevalence. Indeed, OSA can facilitate arrhythmia through intermittent nocturnal hypoxemia/hypercapnia, intrathoracic pressure shifts, sympathovagal imbalance, oxidative stress, inflammation, and neurohumoral activation. Dramatically, OSA has a negative impact on treatment by reducing the success rate of key procedures: AADs, electrical cardioversion, and catheter ablation. Some studies have even shown that an appropriately treating OSA may improve rhythm control in patients with atrial fibrillation.

Therefore, the ESC recommends testing for OSA before treating patients with symptomatic atrial fibrillation to reduce its recurrences, although it doesn’t recommend how to test and manage OSA in this guideline.

ESC: Resistant hypertension (16)

Obstructive sleep apnea (OSA) is highly prevalent in patients with resistant hypertension, with a prevalence between 60% and 84%, possibly up to 90%. 

Other sleep abnormalities can also be seen (e.g., shorter sleep duration, reduced sleep efficiency, reduced REM sleep). The mechanism behind this high rate of comorbidity is thought to be upper airway oedema and neck caused by increased fluid retention, probably due to a change in the production of aldosterone.

Treating OSA in patients with resistant hypertension leads to a statistically significant reduction of blood pressure. The ESC then recommends: “(…) given the high prevalence of often severe OSA in patients with RH and the potential benefit of CPAP to enhance BP control, clinicians should vigorously screen such patients for symptoms of OSA (…)”.

AHA: Stroke (17)

Sleep management is highlighted in the 2021 guidelines on the secondary prevention of stroke, jointly issued by the American Heart Association and American Stroke Association. Obstructive sleep apnea is common among patients with stroke (around 40%), but it is often underdiagnosed.

There is still a lack of evidence on the impact of treating OSA for the recurrence of stroke, but there is clear evidence showing that treating improves daytime sleepiness, blood pressure, sleep-related quality of life, and physical functioning. Because OSA screening questionnaires are inconsistent in patients with stroke and given the high prevalence, sleep studies are justified.

New tool for cardiologists in sleep disorder screening

Brizzy is a novel addition to the toolkit of cardiologists for the screening of sleep-related breathing disorders. This tool has been developed with a vision to simplify the process of interpreting home sleep studies and to make the analysis more efficient, ultimately saving time.

Simplicity for home use

Brizzy distinguishes itself through its simplicity. It features the innovative JAWAC sensor, a single, user-friendly device comprising two small electromagnets, one positioned on the forehead and the other on the chin. This setup is designed to track jaw movements, enabling easy and non-intrusive monitoring by patients in the comfort of their homes.

Accuracy and Reliability

Brizzy's unique ability to measure jaw activity offers a reliable biomarker for respiratory effort, closely correlating with oesophageal pressure and EEG measurements. This precision allows for a more comprehensive assessment of sleep-related events, surpassing the capabilities of standard polygraphs. It's noteworthy that Brizzy's REIJAWAC index shows a high correlation with the Respiratory Disturbance Index (RDI) observed in lab-based polysomnography, as detailed in the study by Martinot et al., 2016 (18).

Clinical Decision Support

Complementing its physical attributes, Brizzy is supported by a user-friendly digital platform designed by Nomics. This platform interprets the collected data and generates automated, understandable reports. The inclusion of an automatic conclusion assists cardiologists in swiftly understanding the results, thereby enhancing patient care efficiency.

For more information on how Nomics tests can help in the screening and diagnosis of sleep-related breathing disorders, please feel free to contact us at cardio@nomicscare.com

References

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Dr. Nicolas Stefenatto

Medical Advisor