Dr. Maria Rosa Costanzo
Maria Rosa Costanzo (Advocate Heart Institute, Naperville, Illinois, USA)
Late Breaking Trials II: Focus on chronic heart failure; 22 May, 08:30–10:00; Paris
Patients with central sleep apnea may, for the first time, have an effective therapy, after positive results with an implantable device that transvenously stimulates the phrenic nerve were presented yesterday.
Central sleep apnea, which can result in cessation of airflow, is common in patients with heart failure and other cardiovascular diseases, and is associated with poor outcomes. Crucially, current therapies have not yielded positive results.
Research has shown, however, that stimulation of the phrenic nerve can result in contraction of the diaphragm similar to that during a normal breath, without disturbing the patient’s sleep.
Maria Rosa Costanzo (Advocate Heart Institute, Naperville, Illinois, USA) explained that the device has two leads: one that senses the patients breathing; and another that stimulates the phrenic nerve. Moreover, the device is able to detect the patient’s position, and so only works when they are asleep in a reclining position.
To examine its safety and effectiveness, Dr Costanzo and colleagues studied 151 patients with an apnea-hypopnea index (AHI) of ≥20, all of whom received the device and were than randomised to having the therapy initiated 1 month after implantation (treatment) or after 7 months (control). The patients were then assessed at 6 months.
Patients in the treatment group were significantly more likely to have a reduction in AHI between baseline and 6 months of ≥50, at 52% versus 11% (p<0.001), which was matched by significant reductions in other apnea-related parameters.
The device was well-tolerated, with 91% of patients free from serious adverse events associated with implantation. There were also no device or implant-related deaths.
Importantly, patients in the treatment group had significant improvements in quality of life measures, with 60% showing moderate or marked improvements on the patient global assessment versus 6% of control patients (p<0.001). Treatment patients also showed significant improvements on the Epworth sleepiness scale (p<0.001).
For Dr Costanzo, the quality of life assessments, which were pre-specified and statistically powered to show a difference, underline the positive nature of the results.
She told Heart Failure Congress News: “If we had improvement just in the sleep parameters but without improvement in how the patient feels, then, while physiologically good, it may not be clinically relevant.”
While further studies will be needed to confirm and build on these findings, Dr Costanzo believes that they could herald a step forward in the treatment of patients with central sleep apnea.
She said: “We feel that the results of this pivotal trial, in itself, are very encouraging and that, based on these results alone, the therapy can potentially be applied in the clinical arena to treat this disorder.”
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