Anne-Christin Stöwhas1, Mehdi Namdar2, Patric Biaggi2, Erich W Russi3, Konrad E Bloch3, John R Stradling4, Malcolm Kohler5. 1. Sleep Disorders Center and Pulmonary Division, University Hospital of Zurich, Zurich, Switzerland. 2. Division of Cardiology, University Hospital of Zurich, Zurich, Switzerland. 3. Sleep Disorders Center and Pulmonary Division, University Hospital of Zurich, Zurich, Switzerland; Zurich Center for Integrative Human Physiology, University of Zurich, Zurich, Switzerland. 4. Oxford Center for Respiratory Medicine, Churchill Hospital, Oxford, England. 5. Sleep Disorders Center and Pulmonary Division, University Hospital of Zurich, Zurich, Switzerland; Zurich Center for Integrative Human Physiology, University of Zurich, Zurich, Switzerland. Electronic address: Malcolm.K@bluewin.ch.
Abstract
BACKGROUND: Preliminary evidence supports an association between obstructive sleep apnea (OSA) and thoracic aortic dilatation. The mechanisms through which OSA may promote thoracic aortic dilatation are incompletely understood. Therefore, we studied the acute effects of simulated apnea and hypopnea on aortic diameter and BP in humans. METHODS: The diameter of the aortic root was measured in 20 healthy volunteers by echocardiography, and peripheral BP was continuously recorded prior, during, and immediately after simulated obstructive hypopnea (inspiration through threshold load), simulated obstructive apnea (Müller maneuver), end-expiratory central apnea, and normal breathing in randomized order. RESULTS:Proximal aortic diameter increased significantly during inspiration through a threshold load (+6.48%; SE, 3.03; P = .007), but not during Müller maneuver (+3.86%; SE, 2.71; P = .336) or end-expiratory central apnea (+0.62%; SE, 2.94; P = .445). Maneuver-induced changes in mean BP were observed during inspiration through a threshold load (-10.5 mm Hg; SE, 2.2; P < .001), the Müller maneuver (-8.8 mm Hg; SE, 2.4; P < .001), and end-expiratory central apnea (-4.2 mm Hg; SE, 1.4; P = .052). There was a significant increase in mean BP on release of threshold load inspiration (+8.1 mm Hg; SE, 2.9 mm Hg; P = .002), Müller maneuver (+10.7 mm Hg; SE, 2.9; P < .001), and end-expiratory central apnea (+10.6 mm Hg; SE, 2.5; P < .001). CONCLUSIONS:Simulated obstructive hypopnea/apnea and central apnea induced considerable changes in BP, and obstructive hypopnea was associated with an increase in proximal aortic diameter. Further studies are needed to investigate effects of apnea and hypopnea on transmural aortic pressure and aortic diameter to define the role of OSA in the pathogenesis of aortic dilatation.
RCT Entities:
BACKGROUND: Preliminary evidence supports an association between obstructive sleep apnea (OSA) and thoracic aortic dilatation. The mechanisms through which OSA may promote thoracic aortic dilatation are incompletely understood. Therefore, we studied the acute effects of simulated apnea and hypopnea on aortic diameter and BP in humans. METHODS: The diameter of the aortic root was measured in 20 healthy volunteers by echocardiography, and peripheral BP was continuously recorded prior, during, and immediately after simulated obstructive hypopnea (inspiration through threshold load), simulated obstructive apnea (Müller maneuver), end-expiratory central apnea, and normal breathing in randomized order. RESULTS: Proximal aortic diameter increased significantly during inspiration through a threshold load (+6.48%; SE, 3.03; P = .007), but not during Müller maneuver (+3.86%; SE, 2.71; P = .336) or end-expiratory central apnea (+0.62%; SE, 2.94; P = .445). Maneuver-induced changes in mean BP were observed during inspiration through a threshold load (-10.5 mm Hg; SE, 2.2; P < .001), the Müller maneuver (-8.8 mm Hg; SE, 2.4; P < .001), and end-expiratory central apnea (-4.2 mm Hg; SE, 1.4; P = .052). There was a significant increase in mean BP on release of threshold load inspiration (+8.1 mm Hg; SE, 2.9 mm Hg; P = .002), Müller maneuver (+10.7 mm Hg; SE, 2.9; P < .001), and end-expiratory central apnea (+10.6 mm Hg; SE, 2.5; P < .001). CONCLUSIONS: Simulated obstructive hypopnea/apnea and central apnea induced considerable changes in BP, and obstructive hypopnea was associated with an increase in proximal aortic diameter. Further studies are needed to investigate effects of apnea and hypopnea on transmural aortic pressure and aortic diameter to define the role of OSA in the pathogenesis of aortic dilatation.
Authors: Giovanni Camen; Christian F Clarenbach; Anne-Christin Stöwhas; Valentina A Rossi; Noriane A Sievi; John R Stradling; Malcolm Kohler Journal: Eur J Appl Physiol Date: 2012-07-18 Impact factor: 3.078
Authors: Christian F Clarenbach; Giovanni Camen; Noriane A Sievi; Christophe Wyss; John R Stradling; Malcolm Kohler Journal: J Appl Physiol (1985) Date: 2013-06-13
Authors: Sonya Craig; Ilias Kylintireas; Malcolm Kohler; Debby Nicoll; Daniel J Bratton; Andrew J Nunn; Paul Leeson; Stefan Neubauer; John R Stradling Journal: J Clin Sleep Med Date: 2015-09-15 Impact factor: 4.062
Authors: Thomas Gaisl; Annette M Wons; Valentina Rossi; Daniel J Bratton; Christian Schlatzer; Esther I Schwarz; Giovanni Camen; Malcolm Kohler Journal: PLoS One Date: 2016-04-12 Impact factor: 3.240