Assessment of pleural pressure during sleep in Marfan syndrome

Snoring and aortic dimension in Marfan syndrome

Recent reports suggest that self-reported snoring, which is a feature of obstructive sleep apnea, is associated with aortic enlargement in Marfan syndrome (MFS). Objective assessment of snoring although lacking, could provide a rational for OSA screening in MFS patients. Our goal in this study was to examine the association between objective measurements of snoring with OSA and aortic size in persons with MFS. Consecutive persons with MFS who reported snoring were recruited at Johns Hopkins, completed the Epworth Sleepiness Scale (ESS) and underwent overnight polysomnography during which inspiratory sound was captured. We measured breath-by-breath peak decibel levels and snoring was defined as flow limitation with sound ≥ 40 dB(A). OSA was defined as an apnea-hypopnea-index (AHI) ≥ 15 or AHI: 5-15 and ESS > 10. Participants' aortic data were collated to ascertain aortic root diameter. Regression models were used to determine the relationship of snoring breath% with OSA and aortic root diameter. In our cohort (M|F:13|16, Age: 37.0 ± 15.5 years, Aortic diameter; 38.9 ± 4.8 mm), a 1-unit increase in snoring breath percentage increased the odds of having OSA by 5% in both the unadjusted (OR = 1.05, p = 0.040) model, and a model adjusted for age and sex (OR = 1.05, p = 0.048). Similarly, a 10-unit increase in snoring breath percentage was associated with a 1 mm increase in contemporaneous aortic-root-diameter in both unadjusted (β = 0.09, p = 0.007), and adjusted (β = 0.08, p = 0.023) models. Objective snoring assessment could provide a means for identifying persons with MFS who need sleep studies, who may also be at risk for more severe aortic disease.

D-dimer in Marfan syndrome: effect of obstructive sleep apnea induced blood pressure surges

Aortic dissection and rupture are the major causes of premature death in persons with Marfan syndrome (MFS), a rare genetic disorder featuring cardiovascular, skeletal, and ocular impairments. We and others have found that obstructive sleep apnea (OSA) confers significant vascular stress in this population and may accelerate aortic disease progression. We hypothesized that D-dimer, a diagnostic biomarker for several types of vascular injury that is also elevated in persons with MFS with aortic enlargement, may be sensitive to cardiovascular stresses caused by OSA. To test this concept, we recruited 16 persons with MFS without aortic dissection and randomized them to two nights of polysomnography, without (baseline) and with OSA treatment: continuous positive airway pressure (CPAP). In addition to scoring OSA by the apnea-hypopnea index (AHI), beat-by-beat systolic BP (SBP) and pulse-pressure (PP) fluctuations were quantified. Morning blood samples were also assayed for D-dimer levels. In this cohort (male:female, 10:6; age, 36 ± 13 yr; aortic diameter, 4 ± 1 cm), CPAP eliminated OSA (AHI: 20 ± 17 vs. 3 ± 2 events/h, P = 0.001) and decreased fluctuations in SBP (13 ± 4 vs. 9 ± 3 mmHg, P = 0.011) and PP (7 ± 2 vs. 5 ± 2 mmHg, P = 0.013). CPAP also reduced D-dimer levels from 1,108 ± 656 to 882 ± 532 ng/mL (P = 0.023). Linear regression revealed a positive association between the maximum PP during OSA and D-dimer in both the unadjusted (r = 0.523, P = 0.038) and a model adjusted for contemporaneous aortic root diameter (r = 0.733, P = 0.028). Our study revealed that overnight CPAP reduces D-dimer levels commensurate with the elimination of OSA and concomitant hemodynamic fluctuations. Morning D-dimer measurements together with OSA screening might serve as predictors of vascular injury in MFS.NEW & NOTEWORTHY What is New? Surges in blood pressure caused by obstructive sleep apnea during sleep increase vascular stress and D-dimer levels in Marfan syndrome. Elevations in D-dimer can be lowered with CPAP. What is Noteworthy? D-dimer levels might serve as a marker for determining the significance of obstructive sleep apnea in persons with Marfan syndrome. D-dimer or obstructive sleep apnea screening is a potential method to identify persons with Marfan syndrome at risk for adverse cardiovascular events.