HEART FAILURE & CENTRAL SLEEP APNEA

• Many Heart Failure patients suffer from Central Sleep Apnea - approximately 40%.^(1-6)

• Central Sleep Apnea in Heart Failure patients can worsen Heart Failure.⁽⁷⁾

• Treating Central Sleep Apnea may allow for better oxygenation, less activation of the sympathetic nervous system and improved sleep.⁽⁸⁾

• Treatment Options for Central Sleep Apnea are limited.

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• About Heart Failure and Central Sleep Apnea

  Heart Failure (HF) is a condition where the heart does not pump enough blood to meet the body's needs. Heart failure can cause a variety of symptoms such as shortness of breath, coughing, ankle swelling and exercise intolerance.

  Heart Failure is a common condition affecting over 5.8 million people in the United States and over 23 million worldwide.⁽¹¹⁾  In the United States alone it is estimated that Heart Failure expenditures exceed $39.2 billion.⁽¹²⁾ It is associated with reduced physical and mental health and decreased quality of life as well as an increased mortality rate.^(13-15)

  In recent years, it has been recognized that some of the symptoms of fatigue and daytime sleepiness in patients with Heart Failure may be due to irregular breathing during sleep called Sleep Disordered Breathing (SDB).  This breathing disorder is a highly prevalent comorbidity for Heart Failure occurring in approximately 75% of HF patients^(16-17)

  SDB is broadly divided into two main syndromes:  obstructive sleep apnea (OSA) and central sleep apnea (CSA).  Both syndromes are becoming recognized for their association with cardiovascular morbidity and mortality. The presence of Central Sleep Apnea has been shown to be an independent predictor of mortality in HF patients.^(7,18)

  

  CSA Speeds Progression of Heart Failure and Reduces Survival Rate⁽⁷⁾

   

• Sleep Disordered Breathing: Central Sleep Apnea Differs from Obstructive Sleep Apnea

  In Obstructive Sleep Apnea, temporary collapse of the upper airway structures during sleep results in a disruption in airflow throughout the sleep cycle causing apneas (cessation of breathing) or hyponeas (shallow breathing).  It is often recognized by loud snoring and daytime sleepiness⁽¹⁹⁾.

  Central Sleep Apnea is a common condition in Heart Failure, occurring in approximately 40% of HF patients^(1-6).  It is characterized by temporary withdrawal of central respiratory drive that results in the cessation of respiratory muscle activity and airflow.  The major pathophysiologic mechanism underlying the development and propagation of Central Sleep Apnea is the abnormal oscillation of the arterial blood carbon dioxide levels above and below the central threshold of ventilation (the apneic threshold).  The oscillation of CO₂ results in repeated apneas and arousals during sleep.  These events may increase sympathetic nervous system activity and trigger pulmonary arterial constriction that can worsen myocardial ischemia, promote arrhythmogenesis and further aggravate cardiac failure.⁽⁸⁾

• How is Central Sleep Apnea Diagnosed?

  The diagnosis of Central Sleep Apnea is based on clinical polysomnography during a sleep study. During sleep, the number of apneic and hypopneic (abnormal decrease in depth and rate of respiration) events per hour are counted and reported as the Apnea Hyponea Index (AHI). AHI is the most common measure of severity of sleep apnea. The severity of the sleep disordered breathing is generally defined as mild (AHI of 5 - 14 events/hour), moderate (AHI of 15 - 30 events/hour), to severe (AHI > 30 events/hour).⁽²⁰⁾ During the sleep study, the apneic and sometimes the hyponeic events are further classified as either Central or Obstructive to determine the best course of treatment.⁽²⁰⁾

   
• References