An AASM guideline update reopens the door to ASV, adds transvenous phrenic nerve stimulation, and shifts success metrics beyond the AHI.

By Alyx Arnett

Central sleep apnea (CSA) has long challenged sleep clinicians with its heterogeneity, limited high-quality data, and a toolbox that often felt either too empty or too risky.

The American Academy of Sleep Medicine (AASM)’s new clinical practice guideline, updating documents from 2012 and 2016, refines both the options and the approach.¹

Notable changes include:

• adaptive servo-ventilation (ASV) reemerges with guardrails,
• transvenous phrenic nerve stimulation is evaluated, and
• individualized, patient-centered care is emphasized, with success metrics expanded beyond the apnea‑hypopnea index (AHI).

“At the end of the day, we’re not just improving polysomnographic findings. We have to make a difference in the lives of our patients,” says AASM guideline task force chair M. Safwan Badr, MD. “Not only do we want to eliminate the events, but we also want to make sure that somebody is actually feeling better.”

What Changed with ASV—and Why

Perhaps the most closely watched update is the guideline’s nuanced reinstatement of ASV for CSA across multiple etiologies, including in patients with heart failure. ASV was recommended in the 2012 guideline but recommended against in the 2016 one.

A decade ago, in 2015, findings from the SERVE-HF trial prompted concern about increased mortality in patients with heart failure and reduced ejection fraction.² The finding ultimately dampened the use of ASV even outside that narrowly defined population.

However, “when we put all the evidence together, there is no mortality signal,” says Badr, who’s also the chair of the Wayne State University School of Medicine department of internal medicine. Some will disagree with the reinstatement, he acknowledges, but the recommendation is the result of the task force following the GRADE process to its conclusion. “I walked into the meeting fully believing that we would maintain the [2016] recommendation not to,” he says.

But, the 2024 ADVENT-HF trial, for instance, found that “ASV had no effect on the primary composite outcome or mortality but eliminated sleep-disordered breathing safely” in patients with heart failure and reduced ejection fraction.³ However, a new meta-analysis conducted in response to that trial says the evidence—four randomized controlled trials—is too limited to “make a firm conclusion on the effects of ASV on [cardiovascular] mortality” and that more randomized controlled trials are warranted.⁴ 

“Out of an abundance of caution,” says Badr, the AASM task force added two considerations for using ASV. “One, it has to be shared decision making, and two, it’s a recommendation that ASV in this population should be offered only in centers that have the expertise, with close monitoring,” he says. Otherwise, “this may not be the right setting to initiate such a complex therapy.”  

For many, the guideline will help recalibrate practice that tightened after SERVE‑HF, according to James Blevins, product manager for sleep diagnostics at Cadwell, who was not involved in the creation of the new guideline. “After the study came out, we saw a lot of labs greatly minimizing, maybe over-minimizing, their ASV,” he says. “I would expect that having more clear guidelines might actually allow appropriate treatment of patients based on more complex comorbidities.”

Sleep physician Nancy Collop, MD, who was not involved in the creation of the new guideline, says, “For now, I would still personally try ASV on most patients, unless they have a low ejection fraction.” The professor emeritus at Emory University School of Medicine and former medical director of the Emory Sleep Center adds, “If I do choose that, I’d tell them about what we know and what we don’t know and then let them decide.”

One New Recommendation

The guideline adds an option that wasn’t available when the previous guidelines were written: transvenous phrenic nerve stimulation. The implantable neurostimulator option stabilizes breathing by stimulating the phrenic nerve during sleep and is recommended after more conservative therapies, due to cost and invasiveness. 

In the United States, the only transvenous phrenic nerve stimulation available for clinical use for central sleep apnea is remedē from ZOLL Respicardia. 

“For PAP-intolerant patients, the device is something you can offer. It’s not for everyone, but for people who are pretty symptomatic or have comorbidities that might benefit from treating their central sleep apnea, it’s a reasonably good option,” says Collop.

With transvenous phrenic nerve stimulation included in the AASM guideline now, that therapy is likely to be offered to more PAP-intolerant CSA patients who would not have been alerted to it as an option before.

One ‘Against’ Recommendation, Two Removals

The guideline also makes one “against” recommendation: Do not use bilevel PAP (BPAP) without a backup rate. “Because BPAP is a pressure support ventilation, without the backup rate, if you have enough pressure support, you will induce central apnea in 100% of the people,” says Badr. “This is how we induce central apnea in our research laboratory.”

Collop notes that many patients have mixed apnea, in which airway dynamics differ from those in pure CSA. “In those patients, I think you’d still try bilevel without a backup rate to start. But what you often will find is, if they have these mixed apneas, then the obstructive will go away, and central will predominate,” she says. “In patients that have pure central sleep apnea, there’s no reason that bilevel without a backup rate should work.”

For CSA, the guideline does recommend BPAP with a backup rate, supported by evidence of clinically meaningful improvements in excessive sleepiness, disease severity, and cardiovascular disease.¹

Additionally, the guideline removes two pharmacologic options: zolpidem and theophylline. The reason for removing zolpidem, says Badr, is “there is actually no literature to support suppressing arousal as a path to eliminate central apnea.”

From AHI to Patient-Reported Outcomes

One of the most meaningful shifts in the guideline, as perceived by Lacey Adams, RPSGT, CCSH, a sleep coach at EnsoData (who was not involved in the guideline’s creation), is its call for individualized care. Rather than focusing solely on eliminating respiratory events or achieving a target AHI, the guideline emphasizes tailoring treatment to the patient’s clinical picture, co-existing conditions, and sleep study findings—and prioritizing patient-reported outcomes.

“Numbers alone don’t tell the full story,” says Adams. “If patients are not seeing themselves in that AHI under five, there’s a sense of failure. So helping the patient and the physician have this collaborative approach on, ‘Yeah, we’re going to pay attention to your numbers but also the way that you’re feeling and your quality of life,’ is going to be a huge shift.”

When determining which outcomes to track, Collop suggests starting with the symptom that brought the patient in. “Was it fatigue or insomnia or sleepiness?…You want to ask, ‘Is this better?’” she says.

The guideline also stresses reassessing patients after treatment begins. 

Adams has seen firsthand why that matters. She recalls a patient with a year of “beautiful” eight-hour CPAP usage, but his AHI was still around 19. After he got set up on a new CPAP, she called him to ask how he was doing and found out he was still symptomatic. With a few comfort setting adjustments, his AHI dropped to 2. “In that case, nobody even looked at his AHI. It was, ‘You’re wearing it. Good job. Keep going,’” she says. “So I love the idea of the follow-up and not just looking at their usage.”

Still, the guideline’s emphasis on outcomes rather than AHI alone does not mean ignoring physiology, says Collop. “Ideally, you want both. You want a low AHI and improved patient outcomes,” she says. “But if you get your AHI down to 10, maybe 15, from 30 or 40, rather than focusing on getting it to five, does the patient feel better? Are they not having desaturations?”

The shift aligns with broader interest in hypoxic burden—how deep and long desaturations are. “With that, we’re looking beyond just the burden of the AHI—how many times per hour this is happening—but also how much this is affecting their cardiovascular health because of how long and how low they’re staying in a hypoxic state,” says Adams.

Practical Pathways: CPAP to Advanced Modalities

While the guideline makes nine conditional recommendations, it stops short of a prescriptive algorithm. 

CPAP, Badr says, is still a good starting point. “We know that 50% of the patients may respond to CPAP, so that is what I suspect most clinicians will do first,” says Badr. 

When central events persist or PAP is not tolerated, clinicians may opt for a different option or combination of options, with selection guided by phenotype, comorbidities, and patient preference. The AASM recommended options are:

• BPAP with a backup,
• ASV,
• Low-flow oxygen,
• Acetazolamide, and
• Transvenous phrenic nerve stimulation.

“Therapy is seldom clear-cut. Management decisions are often imprecise and must constantly be guided by evolving changes in sleep, respiration, wake symptoms, underlying disease, and patient experience,” says Teofilo Lee-Chiong, MD, medical liaison lead of sleep and respiratory care at Philips. “Thus, successful outcomes depend not so much on relying on one effective therapy, but on having many treatment options available.”

Consider Etiology

Collop encourages clinicians to phenotype CSA, as etiology can shape what works. “Figure out, ‘Why does the patient have CSA?’ Is it because they have heart failure? Do they have it because they’re on opioids? Do they have it because it developed after they started CPAP—so, treatment-emergent? Or is it truly idiopathic, and we don’t know why they have it? Sometimes which category the patient falls in helps you determine what treatment might be better or appropriate,” she says. 

The guideline breaks the recommendations down by etiology. For instance, transvenous phrenic nerve stimulation is recommended for primary CSA and CSA due to heart failure, while ASV is recommended for primary CSA, CSA due to heart failure, CSA due to medication or substance use, treatment-emergent CSA, and CSA due to a medical condition or disorder. 

However, Collop notes that many trials lump etiologies together and that more studies are needed “based on what the underlying problem is.”

Documenting Advanced Device Settings

Sleep labs are increasingly seeing patients with more complex sleep-disordered breathing, possibly driven by the effects of long COVID, medication interactions, and home sleep testing. 

Home sleep testing, Blevins adds, “has increased the volume of patients we’re seeing and trying to diagnose and treat. One side effect of that is pulling off those that are simple and redirecting those that are not directly into the lab,” he says. “The balance of complex to simple OSA has been notably shifting for 10 years and just continues to get more complex.”

As labs encounter more complex cases and potentially incorporate more complex therapies, “it’s really important to document every detail and change that techs do through these advanced modalities to better inform physicians in providing therapy prescriptions,” Blevins says. 

Jill West, RPSGT, CCSH, a sleep clinical specialist at Cadwell who was not involved in the update, says the guideline “validates a higher level of clinical skill” and requires encouraging “not just looking at what are my lab protocols, but what other treatment options are available out there—medicines, surgical interventions?” she says. 

West, a member of the Board of Registered Polysomnographic Technologists’ (BRPT) board of directors, says the BRPT is developing an Advanced Titration Certificate as a tool to help standardize competencies for managing advanced modalities. “When you have newer techs enter the field, although they have the RPSGT credential, they may not have the experience to appropriately manage some of these more complex cases,” she says. 

She says the certificate encourages techs, providers, and facilities to engage in ongoing education and adopt restrictions for how and who can handle advanced cases.

Gaps and What’s Next

Stakeholders say the next steps include both stronger evidence and continued refinement in clinical practice. Badr notes that comparative effectiveness trials—including head-to-head studies and combination-therapy research—would help clarify where each treatment fits. Collop adds that the field would benefit from CSA-specific patient-reported outcome measures and more precise phenotyping to better match trials to real-world subgroups.

On the device side, the update’s inclusion of ASV may give clinicians greater latitude when managing patients who do not respond to CPAP and have heart failure. Still, “I suspect that clinicians may divide that depending on how low the ejection fraction,” says Badr. “So maybe just a little bit decrease in the ejection fraction, they feel comfortable, but if it’s really low, they may not.”

For clinicians, Collop sees two practical takeaways: revisit ASV competency and recognize transvenous phrenic nerve stimulation as a guideline-supported option, even if that requires referral.

To Badr, the update signals a broader shift in philosophy: CSA is not merely an incidental polysomnographic finding. “Given the fact that we’re able to show improvement, not just in the number of respiratory events but in patient-reported outcomes, it means that we are making a favorable difference by treating central apnea, and we’re advocating treating central apnea in those who are symptomatic,” Badr says.

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