Download Sleep-disordered breathing in heart failure

Sleep-disordered breathing in heart failure
Prof. Dr. Olaf Oldenburg
Herz- und Diabeteszentrum NRW
Georgstr. 11
32545 Bad Oeynhausen
GERMANY
[email protected]
SUMMARY
Sleep-disordered breathing (SDB) is a highly prevalent but underappreciated co-morbidity in heart
failure. The following presentation and educational material provides an overview about current
evidence of different types of SDB in heart failure, their impact on mortality, and data on specific
therapies with respect to changes in heart failure parameters and mortality.
Initially, this presentation was mending to focus only on obstructive sleep apnea (OSA) and its role in
heart failure. However, recent findings on central sleep apnea (CSA) and Cheyne-Stokes respiration
(CSR) in heart failure patients with reduced left ventricular function (HFrEF), the SERVE-HF trial,
made it necessary to include CSA and CSR as well.
Most studies on SDB in heart failure, as well as in most cardiac patients, are done in patients with
predominant obstructive or central sleep apnea. However, one has to keep in mind that SDB in those
patients may include more than those two types. As large-scale and randomized trial in OSA/CSA and
heart failure are scare, almost no evidence exists regarding the following other types of SDB (see
ICSD-3):
Very recent studies on SDB in heart failure (e. g. SERVE-HF, CAT-HF), as well as new European
heart failure definitions, demand a clear differentiation of heart failure due to reduced left ventricular
ejection fraction (HFrEF, LV-EF<40%) and those with preserved left ventricular ejection fraction
(HFpEF, LV-EF>50%). In addition a new class of heart failure with a LV-EF of 40-50% (HFmrEF)
was introduced.
HFpEF, HFmrEF, and HFrEF may be present in heart failure patients being in a chronic stable phase
or requiring hospitalization because of acute decompensation (ADHF).
These definitions seem to be very complicated, but may even not be detailed enough, since important
confounding factors, especially for any kind of positive airway pressure (PAP) therapy, like right
heart function, blood pressure and fluid load are not considered.
Sleep Apnea and Sleep Apnea Syndrome
Sleep-disordered breathing is usually defined and graduated according to the number of apneas and
hypopneas during sleep (AHI). In addition, symptoms of non-restorative sleep like daytime sleepiness
and specific questionnaires (e. g. Epworth Sleepiness Scale, ESS), define whether a patients is
symptomatic and SDB is syndrome or not (e. g. obstructive sleep apnea syndrome = obstructive sleep
apnea with AHI ≥ 5 plus ESS ≥ 10). However, there is no specific symptom or a validated
questionnaire in heart failure patients with SDB. Thus, none of these symptoms or questionnaires can
be used in the diagnosis or graduation of SDB in heart failure patients.
Apnea-Hypopnea-Index (AHI) and Hypoxemic Burden
A recent long-term follow-up study in HFrEF patients identified hypoxemic burden, defined as the
time a patient spend with an oxygen saturation below 90% during the night, to be a more predictive
and robust marker of survival compared to AHI. Thus, additional metrics besides AHI seem to be
necessary to identify heart failure patients (HFrEF) at risk and to decide whether treatment is
necessary and appropriate or not.
Obstructive Sleep Apnea
OSA is thought to be a risk factor for the development of heart failure. Some epidemiological data
support the concept of severe OSA leading to the development of HFrEF. In addition, OSA may also
trigger diastolic dysfunction and HFpEF, but there is no sufficient data on this concept. In general,
CPAP treatment of OSA is supported by recent guidelines, including the European heart failure
guidelines. However, no large randomized controlled trial (RCT) on outcome exists.
Central Sleep Apnea
It is currently under debate, whether CSA and CSR in particular need to be treated in heart failure
patients. A contraindication exists for ASV-treatment (Adaptive Servoventilation) of CSA in stable
HFrEF, since the SERVE-HF trial discovered an increased all-cause and cardiovascular mortality.
However, this applies for HFrEF patients fulfilling SERVE-HF criteria (chronic stable NYHA III and
IV, II with hospitalization within the last 2 years; LV-EF ≤ 45%; predominant CSA) and being ASVtreated.
Outcome studies have to prove benefit and safety of CSA treatment in HFrEF as well as in HFpEF or
HFmrEF.
Conclusion
SDB is gaining more awareness within the cardiac community. Screening for SDB will be performed
by an increasing number of cardiologists and heart failure specialists. However, specific treatment of
SDB in heart failure requires cardiac knowledge and sleep medicine expertise. Thus a close
collaboration of these experts is mandatory as well as RCTs on outcome.
FURTHER READING
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Arzt M et al., JACC-HF 2016 – Prevalence and predictors of SDB in HFrEF
Bradley TD et al., NEJM 2005 – CANPAP – Study results
Cowie MR et al., NEJM 2015 – SERVE-HF study results
Kaneko Y et al., NEJM 2003 – CPAP effects on HFrEF patients with OSA
Khayat R et al., Eur Heart J 2015 – Prognostic impact of SDB and its therapy in ADHF
Oldenburg O et al., Eur Heart J 2016 – Hypoxemic Burden as the most robust prognostic
parameter in HFrEF
Ponikowski P et al., Eur Heart J 2016 – ESC Heart Failure Guidelines