Effect of OSA on RV Heamodynamics and Function

Obstructive sleep apnea (OSA) is a frequently under diagnosed condition that has emerged as an increasing medical problem with important social and financial implications worldwide. OSA is a well established risk factor for systemic hypertension , myocardial infarction or stroke.

Obstructive sleep apnea syndrome (OSAS) is characterized by repetitive collapse of the upper airway during sleep .The obstructive apneic event is associated with considerable breathing efforts against a totally or partially occluded upper airway, and apnea is terminated by an arousal and heavy snoring as airflow is restored. Severity of OSAS is described according to total number of apneas and hyperpneas per hour of sleep, which is named as the apnea-hypopnea index (AHI).

Cardiovascular disturbances are the most serious complications of OSAS. These complications include heart failure, acute myocardial infarction, nocturnal arrhythmias, stroke, systemic and pulmonary hypertension. All these cardiovascular complications increase morbidity and mortality of OSAS.

Currently, sleep apnea is accepted as one of the identifiable causes of hypertension. Also, OSAS is closely associated with obesity and ageing.

There is conclusive evidence that OSAS influences right heart function (the pathophysiological consequences of sleep apnea-hypopnea might result in an imbalance in myocardial oxygen delivery/consumption ratio, activation of sympathetic and other neurohormonal systems, and increased right and left ventricular after load )

Inclusion criteria

• Subjects diagnosed as OSA with age range from 18 to 70 years
• Glomerular filtration rate (MDRD formula-based) > 60 ml/min
• Arterial hypertension diagnosed according to the European Society of Hypertension 2013 Guidelines.

Exclusion criteria

• Mental illness
• Acute and chronic inflammation
• Heart failure III or IV grade
• Chronic administration of drugs with confirmed nephrotoxicity and/or sympathicomimetics
• Obstructive and restrictive pulmonary diseases which may deteriorate the function of the respiratory system