Cardiovascular Effects of Obstructive Sleep Apnoea Syndrome

Obstructive sleep apnoea syndrome affects 4% men and 2% women. It is the most common sleep disordered breathing and is associated with recurrent episodes of upper airway collapse during sleep. Arousal from sleep is required to re-establish the airway patency. This distortion of sleep pattern, repetitive awakening and nocturnal hypoxia lead to pulmonary and systemic hypertension as well as other cardiac and metabolic complications. Cardiovascular disturbances like systemic hypertension, acute myocardial infarction, nocturnal arrhythmias, corpulmonale and sudden nocturnal death are serious complications of obstructive sleep apnoea syndrome.

To study the association between cardiovascular abnormalities/cardiovascular risk factors and apnoea hypopnoea index (AHI) in patients diagnosed with obstructive sleep apnoea syndrome.

50 patients diagnosed with obstructive sleep apnoea syndrome were divided in to 3 grades-mild, moderate and severe OSAS as per American Academy of Sleep Medicine. Patients were interviewed in detail, clinically examined and investigated (random blood sugar, lipid profile, thyroid function tests chest roentgenogram, ECG and 2D echocardiogram). On basis of history, examination and investigations patients were diagnosed of having hypertension, diabetes mellitus, hypothyroidism, hyperlipidemia and ischaemic heart disease. The prevalence of these associated disease with OSAS and its statistical association with grades of severity of OSAS was calculated.

Frequency and Percentage table, association among study group: Chi-Square test and Fisher Exact test.

In our study the prevalence of hypertension was 48%, diabetes mellitus was 38%, hypothyroidism was 18%, hyperlipidaemia was 30% and ischaemic heart disease was 34%. 24% patients of OSAS in our study had history of smoking.