Improvement of Oxygen Saturation Levels is Associated with Response to Adaptive Servo-Ventilation Therapy in Heart Failure Patients

Abstract

Although adaptive servo-ventilation (ASV) therapy is considered clinically beneficial to patients with heart failure (HF), a large proportion of patients fail to show improvement in HF. We aimed to identify reliable markers indicative of a favorable response to ASV.We evaluated 103 consecutive patients with New York Heart Association (NYHA) class II-IV HF who were scheduled for ASV therapy for 3 months. Patients were classified as responders if their brain natriuretic peptide levels were decreased after 3 months.Twenty-one patients (20.3%) failed to respond to ASV. No significant differences were observed between responders and nonresponders with regard to NYHA classification, age, gender, body mass index, drug therapy, and cardiovascular risk factors. Polysomnography showed no significant baseline differences between the 2 groups in the apnea-hypopnea index (AHI) and percent sleep time of oxygen saturation level below 90% (responders, 4.7% ± 9.2%; nonresponders, 3.7% ± 6.0%; P=0.68). The percent sleep time of oxygen saturation level below 90% is similar parameter as cumulative percentage of time at a pulse-oximetry oxygen saturation below 90% (CT90%) which is measured by in-home screening. We named it "Modified CT90%". After ASV therapy for 3 months, NYHA classification remarkably improved in responder group. Logistic regression analysis revealed that improvement of modified CT90%<1 was independent factor for the responder group. The adjusted odds ratio was 0.685 (95% confident interval 0.485 -0.967, P=0.03).Our study suggests that improvement of modified CT90%<1 at 3 months is associated with a favorable response to ASV therapy.