Systemic Congestion as a Determinant of Efficacy in Adaptive Servo-Ventilation Therapy: A Retrospective Observational Study

Background: The optimal criteria for patient selection in the context of adaptive servo-ventilation (ASV) therapy remain a subject of ongoing investigation. We postulate that baseline plasma volume, assessable through several straightforward clinical parameters, might be correlated with a more pronounced reduction in plasma B-type natriuretic peptide (BNP) levels following mid-term ASV therapy. Methods: We included patients diagnosed with congestive heart failure who had received continuous ASV therapy for a minimum of three months. The primary outcome of interest was the extent of decline in logarithmically transformed plasma BNP levels, defined as a decrease of more than 0.10 during the 3-month ASV treatment period. Results: A total of 66 patients were included in the study. The median age of the cohort was 66 years, with 53 patients (80%) being male. The median plasma volume status at baseline was −16.9%, and patients were categorized into two groups based on this median value. Patients with elevated baseline plasma volume status experienced a statistically significant reduction in plasma BNP levels (p = 0.016), whereas those with lower plasma volume exhibited no significant change in BNP levels (p = 0.23). A higher baseline plasma volume status was independently associated with a significant reduction in plasma BNP levels, with an adjusted odds ratio of 1.036 (95% confidence interval: 1.01–1.07, p = 0.032). Conclusions: The presence of systemic congestion at baseline, quantified by the estimated plasma volume status, may serve as a crucial determinant of the efficacy of ASV therapy, leading to improvements in plasma BNP levels among patients suffering from congestive heart failure.