Abstract
OBJECTIVES This randomized, controlled trial aimed to investigate whether acute improvement of pulmonary congestion would reduce the severity of Cheyne-Stokes respiration (CSR) in patients with chronic heart failure (CHF). METHODS Twenty-one consecutive patients with CHF and CSR (apnea-hypopnea index [AHI] ≥15/h) underwent right heart catheterization with titration of intravenous (IV) glyceryltrinitrate (GTN) to a maximum tolerable dosage and inhalation of iloprost 10 μg/mL after a washout phase. Maximum tolerable dosages of GTN and iloprost were randomly applied during full cardiorespiratory polysomnography within two split-night procedures and compared with IV or inhaled sodium chloride (NaCl) 0.9 %, respectively. RESULTS GTN (6.2 ± 1.5 mg/h) and iloprost significantly lowered \mean pulmonary artery pressure (20.1 ± 9.0 to 11.6 ± 4.2 mmHg, p < 0.001 and 16.9 ± 7.9 to 14.2 ± 6.4 mmHg, p < 0.01, respectively). Pulmonary capillary wedge pressure was only reduced by GTN (14.0 ± 5.6 to 7.2 ± 3.9 mmHg, p < 0.001), and there was no significant change in the cardiac index. Sleep studies revealed no significant improvement in markers of CSR severity, including AHI, central apnea index, and CSR cycle length following GTN or iloprost treatment. Significant decreases in blood pressure, mean oxygen saturation, and S3 sleep were documented during GTN infusion. CONCLUSIONS Acute improvement of pulmonary congestion by GTN had no immediate impact on CSR severity. Future investigations must therefore include longer treatment periods and treatment regimens that have positive, rather than negative, additional effects on peripheral and central chemoreceptors and sleep structure. TRIAL REGISTRATION German Clinical Trial Registry-ID:DRKS00000467 ( www.germanctr.de ).
