◊ Atrial fibrillation is a condition where the atria and ventricles are beating out of sync, resulting in a irregular rhythm.
◊ Can be asymptomatic, or c/o palpitations, shortness of breath, fatigue, chest pain, etc.
Text of PowerPoint slides used by Sheree Chen, M.D. at January 4, 2006 A.W.A.K.E. meeting.
OSA AND CARDIAC DISEASES
OSA AND IMPACT ON VARIOUS CARDIAC DISEASE
◊ Marfan’s Syndrome
◊ Hypertension
◊ Cardiovascular Diseases
◊ Atrial Fibrillation
Marfan Syndrome
◊ Incidence: 2-3/10 000
◊ Affects all races and sexes equally
◊ Caused by mutations in a gene that encodes for fibrillin-1 (FBN1)
◊ Fibrillin is a major constituent of microfibrils which are components
of the extracellular matrix that are widely dispersed and perform numerous functions
◊ Several hundred distinct mutations in FBN1 have been identified
in different families and only a few have emerged by chance in untreated patients.
Table 70-14. Diagnostic Criteria for Marfan Syndrome
Phenotypic Manifestations*
Skeleton- Joint hypermobility, tall stature, pectus excavatum,
reduced thoracic
kyphosis, scoliosis, arachnodactyly, dolichostenomelia, pectus carinatum,
erosion of the lumbosacral vertebrae from dural ectasia
Eye- Myopia, retinal detachment, elongated globe, precocious
cataracts,
ectopia lentis
Cardiovascular- Mitral valve prolapse, endocarditis, dysrhythmia,
dilated
mitral annulus, mitral regurgitation, tricuspid valve prolapse, aortic regurgitation,
aortic dissection, dilation of the aortic root
Pulmonary- Apical blebs, spontaneous pneumothorax
Skin and integument- Inguinal hernias, incisional hernias,
striae atrophicae
Central nervous system- Attention deficit disorder, hyperactivity,
verbal-performance discrepancy, dural ectasia, anterior pelvic meningocele
Family history
If the family history is positive for a close relative clearly affected by
Marfan syndrome, to make the diagnosis in the patient, a major criterion
should be present as well as findings in one other system.
If the family history is negative or unknown, to make the diagnosis, the patient
should have one major criterion and manifestations in two other systems.
*Manifestations are listed within each organ system
in increasing specificity for
Marfan syndrome, although none is completely specific; those indicated by are
the most specific and constitute major criteria.141
For patients with well documented family history of Marfan syndrome, involvement of any one of the three organ systems may be sufficient for the diagnosis to be made. In patients without a positive family history, the patient must have characteristic body habitus plus either aortic root dilation or ectopia lentis. Homocystinuria must be excluded in patients with ectipia lentis.
Marfan and OSA
◊ Peter A. Cistulli and Collin E. Sullivan first reported high prevalence
of OSA in patients with Marfan’s syndrome in 1991.
◊ In 1993, they reported 64% of randomly recruited patients with
Marfan’s syndrome (n=25) had OSA with a mean AHI of 20+/-3.
◊ Since that time, various theories have been postulated.
Hypothesis For Increased Prevalence of OSA in Patients
With Marfan Syndrome
◊ Two hypothesis that have been studied are:
◊ Increased laxity of upper airway in people with Marfan’s
syndrome leads to increased collapsibility resulting in apneas.
◊ Increased nasal airway resistance along with narrow maxilla contributing
to OSA.
◊ Treatment of OSA in Marfan’s syndrome will in general be
the same as in the general population with OSA. However, more awareness of this
will help make the diagnosis.
Aortic Root Dilatation in Marfan’s Syndrome
and OSA?
Peter A. Cistulli, Collin E. Sullivan et al
◊ They report two cases of Marfan’s syndrome with coexistent
OSA in which treatment with nasal continuous positive airway pressure was associated
with attenuation of aortic root dilation.
◊ They speculate that coexistent OSA promotes progressive aortic
dilatation in some patients with Marfan’s.
Implications
◊ Patients with Marfan Syndrome should be questioned for symptoms
of OSA (i.e.. Excessive daytime sleepiness, snoring, neurocognitive changes).
OSA and Hypertension
◊ Hypertension (HTN)
is defined as a systolic blood pressure (SBP) > 140 mmHg and diastolic blood
pressure (DBP) of > 90 mmHg.
◊ Current recommendation is to aim for SBP of 110 - 120 mmHg and
DBP of 70 - 80 mmHg.
◊ HTN is a risk factor for coronary artery disease, renal disease,
and stroke.
◊ Causes of HTN are multifactorial (essential, familial, secondary
causes).
◊ Treatment includes exercise/weight loss, limit salt intake, and
medications, and treatment of underlying cause if it is secondary HTN.
OSA and HTN
◊ OSA has be observed to be strongly associated with HTN.
◊ Some believe OSA to be an independent risk for future HTN.
◊ Treatment of OSA has been observed to improve blood pressure.
◊ There has been a lot of cross-sectional and observational studies,
but no large prospective studies thus far.
Analysis From the Sleep Heart Health Study (SHHS)
◊ Between 11/95 - 1/98, 6,424 individuals was assembled from more
than 23,000 participants in several population-based studies of cardiovascular
disease (CVD) in diverse US populations.
◊ Lower age boundary was 40 y/o, but no upper age boundary.
◊ Sleep studies were performed on all the participants and RDI quantified.
◊ They were followed out from the time of enrollment.
SHHS Findings on HTN
◊ OSA is associated with systolic/diastolic HTN in those aged <
60 y/o.
◊ No association was found between OSA and systolic/diastolic HTN
in those aged > 60 y/o.
◊ Isolated systolic HTN tend to be more prevalent in the elderly.
◊ No association was found between OSA and isolated systolic hypertension
in either age groups.
Implications
◊ Should we be screening patients < 60 y/o with HTN for OSA or
vice versa?
◊ Treatment of OSA should aide in treatment of HTN in a subgroup
of patients.
OSA and Cardiovascular Disease
◊ Association between OSA and CVD is weaker.
◊ From SHHS, the percent of sleep time in hypoxemia was more strongly
associated with prevalent CVD. Sleep fragmentation per se, did not seem to be
associated with CVD.
OSA and Atrial Fibrillation
◊ Atrial fibrillation is a condition where the atria and ventricles
are beating out of sync, resulting in a irregular rhythm.
◊ Can be asymptomatic, or c/o palpitations, shortness of breath,
fatigue, chest pain, etc.
OSA and Atrial Fibrillation
◊ Unknown if OSA is a risk factor for development of atrial fibrillation.
◊ There have been studies done to suggest untreated/unrecognized
OSA decreases the chance for successful cardioversion back into sinus rhythm
and may increase the risk of recurrence of atrial fibrillation.
Mechanisms of How OSA Can Impact on Cardiac Disease
◊ OSA induces intermittent hypoxemia, carbon dioxide retention,
sympathetic activation, and abrupt surges in arterial pressure.
◊ OSA can be associated with daytime sympathetic hyperactivity.
◊ All the above mentioned can increase the risk of thrombotic events
through platelet and inflammatory activation. It does contribute to HTN
Conclusion
◊ Strong association between OSA and HTN in patients < 60 y/o.
◊ Some association between OSA and cardiovascular disease and atrial
fibrillation.
◊ Results from SHHS need to be replicated in prospective, cohort
data. If replicated, will be of public health importance and impact on treatment
for certain cardiac diseases.