A Wake-Up Call –The Alarming Truth About Snoring and Heart Disease

By Monica J. Salas, MD

Introduction

An old Irish proverb states “A good laugh and a long sleep are the best cures in the doctor's book” and few would disagree. However, unfortunately, long and good quality sleep is becoming more and more elusive in modern society. This is due to a variety of factors, one of the more common ones is Obstructive Sleep Apnea (OSA), which is a chronic disorder characterized by obstructive apneas, hypopneas, and/or respiratory effort-related arousals caused by repetitive collapse of the upper airway during sleep. OSA often goes undetected by the individual experiencing it, but frequently is identified by the presence of snoring. As the most common sleep-related disorder in the world, it is estimated that approximately 1 billion people worldwide suffer from the condition.1 Driven by the global obesity epidemic, (obesity being the most common risk factor for OSA), there is ever-increasing morbidity related to the condition. One of the most serious outcomes of OSA is heart disease, which may include arrhythmias, congestive heart failure, sudden cardiac death and more. In other words, unbeknownst to many, snoring just may be the canary in the coal mine for your heart.

Pathophysiology

How does a seemingly benign event like snoring have such serious consequences? The repetitive episodes of apnea and/or hypopnea that patients with OSA experience due to upper airway obstruction lead to intermittent hypoxemia, hypercapnia, endothelial dysfunction from oxidative stress, alterations in cardiac output and venous return to the heart, and recurrent sleep arousals (which may or may not be recognized by the patient). Although the arousal causes restoration of upper airway patency and normal breathing patterns, the result of these repetitive events is chronic hemodynamic, autonomic, metabolic and inflammatory effects on the body.

A common finding is the increased heart rate and blood pressure that come with increased sympathetic activity associated with OSA events. This hemodynamic aberrance, in conjunction with the other aforementioned changes caused by OSA, is strongly associated with heart disease of different varieties.2

Cardiovascular Diseases Associated with OSA

There is a well-known association between hypertension and OSA, approximately 50% of those with OSA have coexisting hypertension.

Astute clinicians will screen for OSA once a diagnosis of hypertension has been established. Patients with elevated morning blood pressure and resistant hypertension are often found to have OSA once polysomnography is performed. There is a consistent correlation between the two conditions even after controlling for potential confounding factors such as age and obesity.3

Atrial fibrillation (AF) has been found in multiple studies, independent of confounding factors such as obesity, to also have a strong association with OSA (up to fourfold higher odds). A large cross-sectional study showed by polysomnography that there was an increased prevalence of AF in patients with and without sleep-disordered breathing (5 vs 1 %), independent of age, sex, BMI and other types of heart disease (odds ratio 4.0, 95% CI 1.0-15.7).4 OSA is also associated with other nocturnal cardiac arrhythmias. Although it is not clear whether the relationship is causal, it does seem to be temporal in nature with arrhythmias occurring more frequently after a hypoxic event.5 This can lead to, in certain cases (such as QT prolongation in those predisposed), sudden cardiac death.

Patients with Congestive Heart Failure (CHF) are also frequently found to have comorbid OSA. Unfortunately, OSA may often be underdiagnosed in this population due to overlapping signs and symptoms between the two conditions, such as nocturnal dyspnea and nocturia (related to diuretics in CHF). It is of utmost importance to identify the presence of OSA in these patients, as it is a negative prognostic factor for CHF and its treatment can improve heart failure related outcomes such as ejection fraction and exercise tolerance.6

Pulmonary hypertension, while typically mild in those without coexisting lung disease, has been found to be present in approximately 20% of patients with moderate to severe OSA and may be associated with decreased long term survival rates.7

There is also increasing evidence that severe OSA is associated with an increased risk for coronary artery disease related cardiovascular events, independent of other risk factors. Comorbid OSA is also a risk factor for worse outcomes in patients with established coronary artery disease.

The Role of the Primary Care Physician

Primary Care Physicians (PCP) play a vital role in reducing the burden of OSA associated heart disease. Rather than simply treating a patient with a prescription anti-hypertensive for their newly diagnosed hypertension or referring them to cardiology for their atrial fibrillation, it is of utmost importance that we ask, “Why?”. Although there may be multiple contributing factors to a patient’s cardiovascular disease and a specialty referral may be indicated in many cases, OSA screening (such as with the STOP-BANG8 questionnaire or the Epworth Sleepiness Scale) and diagnostic evaluation (polysomnography) should always be part of the picture. In most cases, this can easily be facilitated by the patient’s PCP. When OSA is appropriately identified, diagnosed and treated (whether through weight loss, positive airway pressure, oral appliances or surgery) through a team effort, this can lead to a significant reduction in cardiovascular morbidity and mortality worldwide.

References

1. Benjafield AV, Ayas NT, Eastwood PR, Heinzer R, Ip MSM, Morrell MJ, Nunez CM, Patel SR, Penzel T, Pepin JL et al. Estimation of the global prevalence and burden of obstructive sleep apnoea: a literature-based analysis. Lancet Respir. Med. 2019; 7: 687–98.

2. Bradley TD, Floras JS. Obstructive sleep apnoea and its cardiovascular consequences. Lancet. 2009 Jan; 373(9567):82-93.

3. Lavie P, Herer P, Hoffstein V. Obstructive sleep apnoea syndrome as a risk factor for hypertension: population study. BMJ. 2000; 320(7233):479.

4. Mehra R, Benjamin EJ, Shahar E, Gottlieb DJ, Nawabit R, Kirchner HL, Sahadevan J, Redline S. Association of nocturnal arrhythmias with sleep-disorded breathing: Sleep Heart Health Study. Am J Respir Crit Care Med. 2006;173(8):910.

5. Monahan K, Storfer-Isser A, Mehra R, Shahar E, Mittleman M, Rottman J, Punjabi N, Sanders M, Quan SF, Resnick H, Redline S. Triggering of nocturnal arrhythmias by sleep-disordered breathing events. J Am Coll Cardiol. 2009;54(19):1797.

6. Bradley TD, Logan AG, Kimoff RJ, Sériès F, Morrison D, Ferguson K, Belenkie I, Pfeifer M, Fleetham J, Hanly P, Smilovitch M, Tomlinson G, Floras JS, CANPAP Investigators. Continuous positive airway pressure for central sleep apnea and heart failure. N Engl J Med. 2005;353(19):2025.

7. Chaouat A, Weitzenblum E, Krieger J, Oswald M, Kessler R. Pulmonary hemodynamics in the obstructive sleep apnea syndrome. Results in 220 consecutive patients. Chest.1996 Feb;109(2):380-6.

8. Pavarangkul T, Jungtrakul T, Chaobangprom P, Nitiwatthana L, Jongkumchok W, Morrakotkhiew W, Kachenchart S, Chindaprasirt J, Limpawattana P, Srisaenpang S, Pinitsoontorn S, Sawanyawisuth K. The Stop-Bang Questionnaire as a Screening Tool for Obstructive Sleep Apnea-Induced Hypertension in Asian Population. Neurol Int. 2016 Apr 1;8(1):6104. doi: 10.4081/ni.2016.6104. PMID: 27127598; PMCID: PMC4830364.

Monica J. Salas, MD is a Board-Certified Family Medicine and Lifestyle Medicine Physician with over a decade of experience. She is co-owner and COO of Salveo Direct Care, a Direct Primary Care and Lifestyle Medicine practice in San Antonio, Texas. She enjoys working with her patients on their wellness journey to achieve their optimal health through prescribing therapeutic lifestyle change strategies. She is also a member of the Bexar County Medical Society (BCMS).