Cardio Sleep Review

Dedicated to the Nexus of Cardiology and Sleep Apnea Management

Issue 3,

Why Cardiologists Should Screen “Asymptomatic” Patients for OSA

by Dr. Jeffrey Shanes
Interventional Cardiologist

Sleep disorders, including sleep apnea, are on the rise, posing a significant health issue in the United States. According to the American Sleep Apnea Association, as many as 22 million Americans suffer from sleep apnea – and of those, as many as 80 percent have cases that are moderate to severe but may not know it. Sleep apnea is widely underdiagnosed and severely underreported, according to an analysis of the Sleep Heart Health Study.1 Untreated, sleep apnea also can lead to a host of cardiac issues including high blood pressure, chronic heart failure, pulmonary hypertension, stroke, and atrial fibrillation.2 Research has even confirmed links between sleep apnea and both type 2 diabetes and depression.3,4 A new study published in the European Respiratory Journal found a possible link between sleep apnea and dementia.5

Dr. Jeffrey Shanes, who has practiced as an interventional cardiologist in Elmhurst, Illinois, said cardiologists are seeing a significant increase in patients with atrial fibrillation. “We are seeing more AFib every day in our routine practices – probably a quarter to a third of patients will have had a diagnosis of AFib and an equal, if not greater, a number of new consults will be diagnosed with AFib. It’s truly an epidemic. It’s unbelievable,” he said. In addition, many patients come to the hospital ER having had a stroke and only then learn that they have AFib, Dr. Shanes said. According to the American College of Cardiology, about 20% to 30% of all strokes are due to AFib. Dr. Shanes believes a part of this increase in AFib is due to a parallel rise in the number of adults with OSA. Research has shown a strong link between OSA and AFib. Both conditions also are linked to aging and the average age of the U.S. population is increasing, Dr. Shanes noted. The good news is that identifying OSA in cardiac patients can help lead to better, more tailored, and preventive treatment, Dr. Shanes said. Indeed, he said, more data is coming out in scientific journals that show treating OSA in patients with AFib can reduce their AFib burden.


Dr. Shanes is so adamant about the benefits of identifying sleep disorders that when he had his own practice, he made screening for OSA a priority. He instituted a practice where he had his medical assistants administer the STOP-BANG questionnaire for every patient. The questionnaire asks patients about their sleeping and snoring habits and looks for known risk-factors for sleep apnea: a neck circumference of 17 inches or more for men and 16 inches or more for women; and a body mass index of greater than 35, which is obese.6 The questionnaire takes less than two minutes to administer, so it doesn’t negatively impact office workflow, he noted. Having such a screening algorithm in place helps identify many more patients with OSA than leaving it to clinical judgment alone, Dr. Shanes said.

Before seeing the patient, Dr. Shanes would review the results of the questionnaire and, if the patients had three or more risk factors, he would strongly suggest they undergo an at-home sleep study. “I would tell the patients, this is why I am concerned about possible OSA, what the implications are, and why I recommend a sleep study.” If the study showed they had sleep apnea, Dr. Shanes also would explain what it could mean for their cardiovascular disease. “Colleagues may vary a little on how many risk factors before they recommend a sleep study, but for me it’s three or more and I would offer them the study,” he noted. “That makes it consistent for every patient.” Dr. Shanes convinced many of his colleagues in his practice to do the same. “We found that the benefit of putting such a screening algorithm in place is that it helped us to identify many more patients with OSA early on,” he said.

Another group of patients who need sleep studies is those who, while in the hospital for another reason whether hip replacement or pneumonia or something else, are placed on monitors that show their heart rate dropping to the 20s and 30s at night, Dr. Shanes said. “In the past, we wouldn’t say too much about that drop,” he said. “But now that we’re so tuned into OSA, those are another type of patient we say must get a sleep study as an outpatient because we don’t do sleep studies in the hospital. We find that a lot of those patients who have heart rates in the 20s and 30s that we discovered by accident when we screen them for sleep apnea, turn out to have it indeed.”

Since he began routinely screening, Dr. Shanes has found that of the patients he recommends for a sleep study, about 60 percent turn out to have moderate to severe sleep apnea. “You wouldn’t have guessed it,” he said. It’s a significant number, and much higher than he could have anticipated, he said. It has made him aware of how widespread a problem sleep apnea is among cardiology patients, motivating him to become an advocate for aggressively identifying patients who have this powerful and independent risk factor for cardiovascular disease.


Dr. Jeffrey Shanes, Interventional Cardiologist

Many cardiologists believe that they can identify patients with OSA simply by taking their medical history, doing a physical exam, and using good clinical judgment, Dr. Shanes said. It is possible, he noted, to “eyeball” patients for risk of OSA. He adds, however, that leaving it up to clinical judgment alone clearly misses many who may be at risk. For whatever reason, patients tend to be reluctant to bring up the fact that they are not sleeping well at night and may be unaware that they are not breathing, he said. Too often, it is only by chance that their spouse or bed partner mentions it during an exam, he said. “People may claim that they don’t feel tired during the day because they don’t realize it until after they are treated and are sleeping better,” he said.

Some cardiologists will order sleep tests only for patients with hypersomnia, snoring, and obesity. However, asymptomatic patients need to be screened as well, Dr. Shanes said. Patients can have OSA and not have overt symptoms or the typical body habitus associated with OSA.

“Identifying patients with OSA is no less important than screening for other cardiovascular risk factors including high cholesterol, hypertension, and diabetes…”

Dr. Jeffrey Shanes, interventional cardiologist

Using diagnostics like calcium scoring and hs-CRP, cardiologists are able to identify patients who are at higher risk for myocardial infarction, stroke, or sudden death. “Diagnosing ‘asymptomatic’ patients who have sleep apnea would add a new dimension in terms of stratifying patients who are at increased cardiovascular risk and may be candidates for more aggressive cardiovascular protective therapies. In addition, the time and cost for screening and testing appropriate patients with a home sleep study are minimal.”


Understandably, Dr, Shanes said, patients are reluctant to go to a sleep center to sleep hooked up to wires, leads and monitors and under constant observation. Not only do they find the in-lab test uncomfortable, but many also have issues even getting to the lab, especially if they are elderly and don’t drive or have transportation, he said.

However, since sleep testing now can be done at home, the vast majority of his patients whom he recommends be tested agree to it, Dr. Shanes said. “And I have not had any patients who have been unable to perform the test with their at-home devices.” Not only is the at-home sleep study easy to do, Dr. Shanes said, “but also we get the results right away. We get a report within 24 to 48 hours. So, we know the results and can send the patient to a sleep specialist if indicated.” The results from the at-home test are reported in a way as to be clear and actionable for the cardiologist who initially ordered the exam, he said. Fortunately, OSA is relatively inexpensive to treat. Basically, patients are given continuous positive airway pressure (CPAP) machines, which prevent the airway from closing during sleep, Dr. Shanes said. A study published in the Journal of the American College of Cardiology Clinical Electrophysiology in 2015 found that the use of CPAP is associated with a significant reduction in recurrence of AFib in patients with OSA.7

In any field, it takes a long time for researchers to come out with the data to support screening and for screening to become part of medical society guidelines, Dr. Shanes said. Screening for sleep apnea is just now getting on cardiologists’ radar, he said. What’s needed to move it along, he said, is “education, education, education.” Much research has been devoted to identifying new risk factors for cardiovascular conditions including stroke, heart attack and congestive heart failure, Shanes said. “Most clinicians have incorporated screenings for metabolic syndrome, hs-CRP, and coronary calcification into their practices in order to identify patients earlier for more aggressive preventive therapies,” he said. It’s time, he added, that cardiologists do the same for OSA because of its link to atrial fibrillation and other cardiovascular diseases. Clearly, patients with OSA need to be identified and treated.

Having cardiologists test for sleep disorders is still very new and evolving, Dr. Shanes said. “It is going to take a little while to figure out exactly what the best role is.” At this time, Dr. Shanes said, “We don’t have large, randomized trials that say if you screen asymptomatic patients for OSA, you’re going to prevent a stroke, you’re going to prevent sudden death, you’re going to prevent AFib. There’s a lot of data out there that sure makes it suspicious for all those types of things.” However, he said, “All the data points in this direction. Sometimes you just have to connect the dots.” Identifying patients with OSA is no less important than screening for other cardiovascular risk factors including high cholesterol, hypertension and diabetes, Dr. Shanes said.


  1. Shahar E, Whitney CW, Redline S, et al. Sleep-disordered breathing and cardiovascular disease: cross-sectional results of the Sleep Heart Health Study. Am J Respir Crit Care Med. 2001; 163:19–25.
  2. Sleep Duration and Quality: Impact on Lifestyle Behaviors and Cardiometabolic Health A Scientific Statement From the American Heart Association, Circulation, November 2016.
  3. Muraki 1, Wada H, Tanigawa T, Sleep apnea and type 2 diabetes, Journal of Diabetes Investigation, Sept. 2018; 5:991-997.
  4. Bixler, E, Gaines J., Vgontzas, A., Obstructive sleep apnoea, and depression: is there an association? European Respiratory Journal 2017, 49: 1700858.
  5. Cross, Nathan, et al, European Respiratory Journal, 2018, Structural brain correlates of obstructive sleep apnoea in older adults at risk for dementia.
  6. The questions are: Do you snore loudly? Do you feel tired, fatigued, or sleepy during the day? Has anyone observed you stop breathing when sleeping? Do you have or are you being treated for high blood pressure?
  7. Shukla, JACC, 2015 Mar-Apr; Effect of Obstructive Sleep Apnea Treatment on Atrial Fibrillation Recurrence: A Meta-Analysis.

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Cardio Sleep Review
Publisher: Itamar Medical
Editor: Melih Alvo

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