Mandibular device on par with CPAP for BP lowering in OSA patients

In the CRESCENT trial, a mandibular advancement device (MAD) was noninferior to a continuous positive airway pressure (CPAP) machine for reducing 24-hr mean arterial blood pressure (MBP) in individuals with obstructive sleep apnoea (OSA), uncontrolled hypertension, and high cardiovascular (CV) risk.

“[In this study, the] noninferiority margin was set at +1.5 mm Hg based on a randomized controlled trial comparing CPAP vs sham CPAP,” said Dr Ronald Lee Chi-Hang from the National University of Singapore, at ACC.24.

At 6 months, 24-hr MBP dropped in the MAD vs CPAP arm (–2.5 vs 0 mm Hg), as did asleep MBP (–2 vs 1 mm Hg). “MAD use led to a substantial improvement in the optimization of BP control, whereas in the CPAP arm, a neutral effect was observed. The noninferiority of MAD against CPAP [was met] because the confidence interval does not exceed the predefined margin of 1.5 mm Hg,” Chi-Hang explained.

The negative between-group differences favoured MAD over CPAP in terms of daytime BP when patients were not wearing the device (–1.83; p=0.009 [systolic] and –0.83; p=0.007 [diastolic]). The effects were more pronounced for nighttime BP (–2.85; p=0.005 and –2.26; p=0.001, respectively). [ACC.24, Featured Clinical Research I]

Adherence was also higher in the MAD vs CPAP arm, with more than half (56.5 percent) of MAD users using their devices for ≥6 hours on average per night, as opposed to only 23.2 percent of those in the CPAP arm. The proportion of patients with average usage of ≥4 hours per night was also greater with the MAD vs the CPAP device (75.3 percent vs 68.7 percent).

“[MAD users] simply used the device longer,” Chi-Hang noted in a press release. “That might also explain why the BP reduction at nighttime, when patients are actually using it, had a better reduction in the MAD arm.”

According to Chi-Hang, the COVID-19 pandemic may have factored in the increased adherence since the study was conducted during the pandemic lockdowns.

Improved sleepiness with both devices

The incidence of excessive daytime sleepiness improved, dropping from baseline to month 6 in both the MAD (from 26.4 percent to 11 percent; difference 15.4 percent; p=0.001) and CPAP arms (from 34.5 percent to 7 percent; difference 27.5 percent; p<0.001).

These findings align with previous evidence showing that MAD improves sleepiness and quality of life, and is better accepted and tolerated, noted Chi-Hang. “MAD reduces airway collapsibility by advancing the mandible by about 5–10 mm during sleep.”

CPAP still first-line, but MAD is promising

A total of 321 participants underwent a sleep study to determine if they had OSA. Of these, 220 individuals (median age 61 years, 85 percent men, median 24-hr SBP 125 mm Hg) were found to have moderate-to-severe OSA. They were randomized 1:1 to receive a MAD or CPAP device and were instructed to use their assigned device for 6 months while sleeping up to a point where they could tolerate it.

“Looking at the totality of evidence available in literature, it is reasonable to say that CPAP is still the first-line treatment until we have more data on the MAD,” said Chi-Hang. “However, many patients either decline CPAP use or find it challenging to stick to treatment.”

“[Therefore,] for patients who truly cannot tolerate or accept using a CPAP [device], we should be more open-minded in looking for an alternative therapy such as a MAD which, based on our study, numerically had a better BP reduction compared with a CPAP [device],” he added.

OSA Tx integral to hypertension control?

Chi-Hang also highlighted the role of OSA management in hypertension control and CV risk reduction. “People should be aware that over 400 million people globally have moderate-to-severe OSA, and it is underdiagnosed and may be a contributing [but modifiable] factor to their high BP.”

“Especially for patients whose BP is hard to control or who have a lot of excessive daytime sleepiness, [it is important to] see a physician about [OSA] and get treated if necessary,” he added.

As the trial was conducted in Singapore with most participants of East Asian descent, the findings may not be extrapolated to other racial and ethnic groups. Studies with more diverse cohorts are thus recommended to reinforce the results.