Clinical impact of adaptive servoventilation compared to other ventilatory modes in patients with treatment-emergent sleep apnea, central sleep apnea and Cheyne-Stokes respiration.

INTRODUCTION: Adaptive servoventilation is a recent ventilatory mode initially designed to treat Cheyne-Stokes respiration (CSR). Recently, the efficacy of ASV has been discussed for the treatment of central sleep apnea (CSA) and treatment-emergent central sleep apnea (treatment-emergent CSA) where other forms of traditional positive airway pressure (PAP) may be insufficient.
OBJECTIVES: To compare the clinical impact of ASV with other forms of PAP in treating patients with treatment-emergent CSA, CSA and CSR.
METHODS: Medical data of all the patients who underwent polysomnography (PSG) with ASV titration were evaluated. The patients were divided into two groups according to the mode of ventilation reimbursed: ASV and PAP (AutoCPAP/CPAP/BIPAP). All patients had a minimal follow-up of 6 months. Both groups were compared in terms of symptoms, apnea hypopnea index, compliance, cardiac function and cardiovascular events.
RESULTS: ASV titration was performed in 33 patients (30M/3F) with a mean age of 69±8 years. The majority (58%) present a treatment-emergent SA and 42% a CSA and or CSR. The median initial diagnostic AHI was 46±22events/h. After the initial diagnosis, 28 patients were treated with PAP and 5 with servoventilation. All of the patients treated with PAP were posteriorly submitted to PSG and ASV titration because of suboptimal response to PAP. Despite a clear indication for ASV, due to differences in reimbursement, 15 patients continued treatment with PAP (12 with AutoCPAP, 1 with BIPAP and 2 with CPAP) and 16 changed to ASV. Two patients were lost in follow-up. In both groups, most of patients present a treatment-emergent SA (53% in ASV group vs. 67% in PAP group) or a CSA/CSR (29.4% in ASV group vs. 20% in PAP). After ASV titration, the mean follow-up was 25±14 months. Both groups (ASV vs. PAP) were similar in terms of compliance (77±23% vs.88±14%) and in terms of Epworth sleepiness scale score (6±5 vs. 7±5). There was a statistical difference in terms of residual AHI: mean AHI was 4±3 in ASV group and 9±3 in PAP group (P=0.005). We found no differences in terms of left ventricular fractional shortening (ASV 33±10% vs. PAP 32±10%). Although no difference was observed between the 2 groups in terms of non-fatal cardiovascular events (3 events in each group), 2 fatal cardiovascular events occurred in the PAP group (sudden death).
CONCLUSIONS: These data confirm that ASV is an efficient treatment in patients with treatment-emergent CSA, CSA/CSR significantly decreasing residual AHI. In both groups, compliance rate was high and sleepiness improved. It is relevant that the 2 patients who died of sudden death were treated with PAP.