P3525Buspirone effect on chemoreflex and central apneas in heart failure

Background Increased chemosensitivity to carbon dioxide (CO2) is an important trigger of central apneas in heart failure (HF), contributing to HF progression and mortality. We hypothesized that buspirone, a 5HT1A receptor agonist that inhibits serotonergic chemoreceptor neuron firing in animals, can decrease CO2 chemosensitivity, thus preventing CA in patients with HF. Methods Sixteen patients with systolic HF (age 71.3±5.8 years, left ventricular ejection fraction 29.8±7.8%) and moderate-severe central apneas (nighttime apnea/hypopnea index AHI≥15 events/hour) underwent a double-blind, placebo-controlled, cross over, randomized study of oral buspirone administration (45 mg/day for 1 week). Results Buspirone reduced CO2 chemosensitivity compared to placebo (1.2 IR [1.1–1.5] vs. 2.0 [1.6–2.2] L/min/mmHg, p=0.008). Furthermore, buspirone improved: the AHI at nighttime (16.5 [8.5–24.7] vs. 27.5 [23.0–37.3] events/hour, p=0.002), and daytime (8.0 [2.3–11.5] vs. 11.5 [6.3–18.8] events/hour, p=0.006); the central apnea index at nighttime (4.0 [1.0–19.0] vs. 12.5 [8.3–27.3] events/hour, p=0.01) and daytime (1.0 [0.0–3.0] vs. 4.0 [1.3–6.0] events/hour, p=0.009); and the oxygen desaturation index at nighttime (4.7 [1.0–11.0] vs. 20.0 [8.7–26.5] events/hour, p=0.004) and daytime (0.2 [0.1–0.7] vs. 1.2 [0.3–4.8] events/hour, p=0.005). Buspirone showed a good safety profile and had no effect on neurohormones, arrhythmias, exercise capacity and mood/daytime sleepiness. Conclusion Buspirone reduces CO2 chemosensitivity and inhibits central apneas both during the day and the night in patients with systolic HF.