Impaired Vasodilator Responses in Obstructive Sleep Apnea Are Improved with Continuous Positive Airway Pressure Therapy

VIRGINIA A. IMADOJEMU, KEVIN GLEESON, SADEQ A. QURAISHI, ALLEN R. KUNSELMAN, LAWRENCE I. SINOWAY, URS A. LEUENBERGER
2002 American Journal of Respiratory and Critical Care Medicine  
Obstructive sleep apnea causes cardiovascular morbidity and premature death. Potential links between sleep apnea and cardiovascular complications are chronically elevated activity of the sympathetic nervous system and abnormal vascular function. To explore vascular function, we determined the reactive hyperemic blood flow (RHBF) responses to 10 minutes of forearm arterial occlusion (plethysmography), blood pressure, and muscle sympathetic nerve activity (MSNA, microneurography) in eight
more » ... y) in eight patients with sleep apnea and in nine nonapneic control subjects. Peak RHBF and vascular conductance were markedly attenuated in sleep apnea compared with control subjects (p Ͻ 0.05). Seven sleep apnea patients were retested after at least two weeks of continuous positive airway pressure (CPAP) therapy. MSNA decreased after CPAP therapy (p Ͻ 0.05, n ϭ 6), whereas blood pressure did not change. After CPAP therapy, peak RHBF and vascular conductance were increased compared with before treatment (p Ͻ 0.05; n ϭ 7). Thus, vascular function is abnormal in sleep apnea and is improved by CPAP therapy. Furthermore, effective CPAP therapy decreases sympathetic activity in sleep apnea. Thus, sympathoexcitation and abnormal vascular function in patients with sleep apnea appear to be linked to the repetitive nocturnal apneic events.
doi:10.1164/ajrccm.165.7.2102003 pmid:11934720 fatcat:4c2sn3vyxzfvbb45n4dpb55pzi