title: Treatment of obstructive sleep apnea reduces arterial stiffness.
abstract: OBJECTIVE
  A close relationship between obstructive sleep apnea (OSA) and atherosclerosis has been reported, but it is still discussed controversially whether OSA affects vascular function and structure independently. Therefore, we prospectively investigated the independent impact of OSA and its treatment on arterial stiffness.
  
  
  METHODS
  One hundred seventy-two patients with suspected OSA were prospectively enrolled in a non-randomized 6-month study to determine whether effective treatment (respiratory events sufficiently reduced and proven compliance) of OSA with continuous positive airway pressure (CPAP) would affect vascular function as measured by augmentation index (Aix) and pulse wave velocity (PWV). Additionally, using a nested case-control, we matched 45 pairs of patients with and without OSA for gender, age, and hypertension.
  
  
  RESULTS
  Overall, OSA (n = 117) was associated with increased Aix (23.6 ± 13.5 vs. 8.9 ± 13.7, p < 0.001) and PWV (9.1 ± 1.6 vs. 7.8 ± 1.6 m/s, p < 0.001) as compared with that in controls without OSA (n = 55). Multivariable analysis and results from the nested case-control cohort showed that OSA was associated with increased Aix and PWV independently from hypertension, age, gender, body mass index, and antihypertensive medications. In 49 effectively treated OSA patients, Aix (baseline 22.0 ± 13.4, follow-up 20.1 ± 12.9, p < 0.01) and PWV (baseline 9.6 ± 1.5, follow-up 8.7 ± 1.4, p < 0.05) had improved. In contrast, ineffectively treated OSA patients (n = 39) showed no change in Aix and PWV.
  
  
  CONCLUSIONS
  This prospective controlled study suggests that OSA is independently associated with increased arterial stiffness. Furthermore, treatment with CPAP significantly reduced arterial stiffness. These findings extend our understanding of the recently shown cardiovascular burden in OSA and help to explain why CPAP treatment proved to ameliorate cardiovascular outcome even in patients without preexisting cardiovascular disease.
authors.affiliation: Department of Internal Medicine I, Marienhospital Herne, Ruhr-University Bochum, Herne, Germany. nikolaus.buechner@rub.de
authors.forename: Nikolaus J
authors.initials: NJ
authors.lastname: Buchner
authors.forename: Ivo
authors.initials: I
authors.lastname: Quack
authors.forename: Johannes
authors.initials: J
authors.lastname: Stegbauer
authors.forename: Magdalena
authors.initials: M
authors.lastname: Woznowski
authors.forename: Adrian
authors.initials: A
authors.lastname: Kaufmann
authors.forename: Lars C
authors.initials: LC
authors.lastname: Rump
mesh_terms: D000328:Adult; D000368:Aged; D050197:Atherosclerosis / Q000503:physiopathology* / Q000628:therapy*; D001794:Blood Pressure / Q000502:physiology; D015331:Cohort Studies; D045422:Continuous Positive Airway Pressure; D003924:Diabetes Mellitus, Type 2 / Q000503:physiopathology / Q000628:therapy; D005260:Female; D005858:Germany; D006801:Humans; D006973:Hypertension / Q000503:physiopathology / Q000628:therapy; D008297:Male; D019186:Mandibular Advancement / Q000295:instrumentation*; D008875:Middle Aged; D017090:Occlusal Splints; D017286:Polysomnography; D011446:Prospective Studies; D012307:Risk Factors; D020181:Sleep Apnea, Obstructive / Q000503:physiopathology* / Q000628:therapy*; D016896:Treatment Outcome; D059289:Vascular Stiffness / Q000502:physiology*