Increased upper airway collapsibility in a mouse model of Marfan syndrome

Association of sleep apnoea risk and aortic enlargement in Marfan syndrome

Background

Marfan syndrome (MFS) is a connective tissue disorder characterised by complex aortic pathology and a high prevalence of obstructive sleep apnoea (OSA). OSA produces intrathoracic transmural stresses that may accelerate aortic injury. The current study was designed to examine the associations between OSA risk and markers of aortic enlargement in MFS.

Method

Consecutive patients with MFS were recruited at Johns Hopkins if they completed a STOP-BANG survey. Composite survey scores were categorised into those with low OSA risk (STOP-BANG <3) and high OSA risk (STOP-BANG ≥3). Participants’ aortic data were collated to ascertain aortic root diameter, dilatation and prior aortic root replacement. Regression analyses were used to examine associations between OSA risk strata and these aortic parameters.

Results

Of the 89 participants studied, 28% had a high OSA risk and 32% had aortic grafts. Persons with high OSA risk had greater aortic root diameter (mm) (ß=4.13, SE=1.81, p=0.027) and aortic root dilatation (ß=2.80, SE=1.34, p=0.046) compared with those with low OSA risk. In addition, the odds of prior aortic root replacement was three times greater in those with high OSA risk compared with those with low OSA risk.

Conclusion

In MFS, high OSA risk is associated with aortic enlargement and a threefold increased risk of having had prior aortic root replacement. These findings invite further exploration of the relationship between OSA and aortic disease in MFS, and studies to clarify whether targeted interventions for OSA might mitigate aortic disease progression in MFS.

Registration number

IRB00157483.

Risk Factors and Inadequacy of Screening for Sleep-Disordered Breathing in Children with Marfan Syndrome

The prevalence of obstructive sleep apnea (OSA) is increased in children and adults with Marfan syndrome (MFS) compared to the general population and has been shown to be associated with rapid aortic root dilation and dissection in adults. Early diagnosis and treatment of OSA may decrease long-term cardiac morbidity. We therefore studied the utility of noninvasive OSA screening tools in children with MFS. We hypothesized that youth with MFS would have higher OSA screening scores than the general pediatric population. Subjects with confirmed MFS were recruited from a single pediatric center. Data collected included cardiac history, retrospective polysomnogram (PSG) data, and prospectively collected Pediatric Sleep Questionnaire (SRBD-PSQ) and Epworth Sleepiness Scale (ESS-CHAD) scores. Fifty-one individuals aged 2-21 years old were identified. Nineteen subjects completed the surveys, 53% female, median age 16 years. Of those that completed the survey, mean SRBD-PSQ score was 0.24 ± 0.21 and mean ESS-CHAD was 6.4 ± 3.7. Comparatively, published normative data for pediatric control subjects were 0.24 ± 0.21 for SRBD-PSQ and 5.4 ± 3.7 for ESS-CHAD. In conclusions, youth with MFS had similar OSA screening scores compared to published pediatric controls. Given these findings and high prevalence of OSA in MFS youth, standard questionnaires may not be an appropriate tool for identifying children at risk for OSA in this population. In the absence of evidence-based guidelines, physicians caring for children with MFS should consider referral for PSG, even in the absence of classic symptoms.

Postural control abnormalities related to sleep deprivation in patients with Marfan Syndrome

BACKGROUND

Marfan syndrome (MFS) is a rare autosomal dominant connective tissue disorder affecting virtually every organ. Sleep disturbances, associated to high collapsibility in upper airways, are common in MFS; daytime sleepiness could lead to reduction in attention and motor coordination, with detrimental effects on balance.

OBJECTIVE

To evaluate otoneurological function in MFS patients, compared to healthy subjects, and to investigate possible correlations with sleep deprivation extent.

METHODS

Forty-one MFS patients underwent a thorough otoneurological examination, video Head Impulse Test (vHIT), and static posturography. Sleep parameters were recorded by home monitoring. Daytime sleepiness and dizziness-related handicap were screened by means of Dizziness Handicap Inventory (DHI) and Epworth Sleepiness Scale (ESS). Results were compared with 49 healthy controls (HC).

RESULTS

DHI and ESS scores were increased in MFS patients (p < 0,01). vHIT scores showed no between-group effect. Classical (surface and length) and frequency-domain posturographic parameters were significantly increased in MFS with respect to HC (p < 0,01). A positive correlation was found between ESS scores and posturographic parameters in MFS patients.

CONCLUSIONS

An impaired postural control, related to the extent of sleep deprivation, was found in MFS patients. Such results could advocate for screening and treating sleep deprivation and balance dysfunctions in MFS patients.

Sleep apnea and the impact on cardiovascular risk in patients with Marfan syndrome

Background

Marfan syndrome (MFS) is an inherited connective tissue disorder characterized by ectopia lentis, aortic root dilation and dissection and specific skeletal features. Obstructive sleep apnea (OSA) in MFS has been described earlier but the prevalence and its relation with the cardiovascular risk is still controversial. This study aimed to further investigate these aspects.

Methods

In this prospective longitudinal study, we performed an attended polysomnography in 40 MFS patients (60% women, 37 ± 12.8 years) and evaluated several cardiovascular parameters through echocardiography, resting electrocardiogram, 24 hr‐Holter monitoring and serum NT‐ProBNP measurements.

Results

We found that OSA was present in 42.5% of the patients and that higher body mass index was the most important factor associated with the presence of OSA. We observed that overweight was present in 27.5% of the patients in the whole cohort and in 55.6% if >40 years. Furthermore, when evaluating the impact of OSA on the cardiovascular system, we observed that patients with OSA tended to have higher systolic blood pressure, larger distal aortic diameters and a higher prevalence of ventricular arrhythmia. These differences were, however, not significant after adjusting for confounders.

Conclusions

Our study shows a high prevalence of OSA and a high prevalence of overweight in MFS patients. We found some trends between OSA and cardiovascular features but we could not establish a solid association. Our study, however might be underpowered, and a multicenter collaborative study could be very useful to answer some important open questions.

Early Impairment of Lung Mechanics in a Murine Model of Marfan Syndrome

Early morbidity and mortality in patients with Marfan syndrome (MFS) -a connective tissue disease caused by mutations in fibrillin-1 gene- are mainly caused by aorta aneurysm and rupture. However, the increase in the life expectancy of MFS patients recently achieved by reparatory surgery promotes clinical manifestations in other organs. Although some studies have reported respiratory alterations in MFS, our knowledge of how this connective tissue disease modifies lung mechanics is scarce. Hence, we assessed whether the stiffness of the whole lung and of its extracellular matrix (ECM) is affected in a well-characterized MFS mouse model (FBN1^C1039G/+). The stiffness of the whole lung and of its ECM were measured by conventional mechanical ventilation and atomic force microscopy, respectively. We studied 5-week and 9-month old mice, whose ages are representative of early and late stages of the disease. At both ages, the lungs of MFS mice were significantly more compliant than in wild type (WT) mice. By contrast, no significant differences were found in local lung ECM stiffness. Moreover, histopathological lung evaluation showed a clear emphysematous-like pattern in MFS mice since alveolar space enlargement was significantly increased compared with WT mice. These data suggest that the mechanism explaining the increased lung compliance in MFS is not a direct consequence of reduced ECM stiffness, but an emphysema-like alteration in the 3D structural organization of the lung. Since lung alterations in MFS are almost fully manifested at an early age, it is suggested that respiratory monitoring could provide early biomarkers for diagnosis and/or follow-up of patients with the Marfan syndrome.