Abstract 10860: Effect of Intensified Diuretic Treatment on Nocturnal Rostral Fluid Shift and Obstructive Sleep Apnea in Uncontrolled Hypertensive Patients
Background: We recently reported that fluid displacement from the legs to the neck during sleep was associated with the severity of obstructive sleep apnea (OSA) in hypertensive patients. We proposed that this nocturnal rostral fluid shift would predispose to OSA via increased nuchal fluid accumulation and narrowing of the pharynx. However, it remains unclear whether such fluid shift plays a causative role in OSA. We hypothesized that intensified diuretic therapy would reduce the severity of OSA and that the reduction would be in proportion to the decrease in overnight rostral fluid redistribution.
Methods: Uncontrolled treated hypertensive patients underwent polysomnography and measurement of overnight changes in leg fluid volume and neck circumference (ΔLFV and ΔNC, respectively). Those with an apnea-hypopnea index (AHI) ≥20 (n=16) received metolazone 2.5mg and spironolactone 25mg daily for 7-days after which the daily dose was doubled for an additional 7-days. Baseline testing was then repeated.
Results: The intensified diuretic therapy reduced the AHI from 57.7±33.0 to 48.5±28.2 (P=0.005), ΔLFV from -418.1±177.5 to -307.5±161.9 mL (P<0.001) and ΔNC from 1.2±0.6 to 0.7±0.4 cm (P<0.001). There was a significant relationship between reduction in ΔLFV and change in ΔNC (r=-0.730, P=0.001). The change in ΔNC correlated significantly with the change in AHI (r=0.680, P=0.004). There was a correlation between reduction in ΔLFV and change in AHI (r=-0.734, P=0.001).
Conclusion: Intensified diuretic therapy reduced nocturnal rostral fluid shift and in turn, the severity of OSA. Our findings provide proof-of-principle that overnight fluid shift plays a causative role in OSA.
- © 2012 by American Heart Association, Inc.