The Role of Sleep Apnea in the Acute Exacerbation of Heart Failure

This study will evaluate whether treating sleep apnea while in the hospital would help heart failure, and assist recovery from the worsening of the heart function more than the current clinical standard of waiting for treatment until the subject have left the hospital.

Heart failure affects more than 2% of the US population and is the only cardiovascular disorder with rising incidence. The annual cost of CHF in 2005 was $ 27.9 billion, large percentage of which is the cost of hospitalizations for exacerbation of CHF. Half of patients with CHF have some form of sleep apnea, and most of them go undiagnosed. Patients with CHF and OSA benefit from treatment with CPAP as an outpatient. The society can benefit from developing recommendations for approaching sleep apnea in the hospitalized CHF patient, which may shorten length of stay, improve functional status of discharged patient, and reduce rehospitalizations.

Target population:

Patients admitted to the OSU Heart Hospital with ADHF routinely undergo a cardiorespiratory sleep study to identify OSA. Patients with ADHF who are newly diagnosed with OSA during the same hospital stay are eligible for this study.

Enrollment:

Given the presence of significant previously unrecognized OSA in 62% of patients hospitalized with ADHF, we expect to need to screen 270 patient volunteers to recruit 170 patients with OSA.

Eligibility for randomization: The criteria for ADHF is admission diagnosis of heart failure; a chief complaint of dyspnea; and ejection fraction of 45% or less. Additionally, elevated left ventricular pressure as indicated by at least one sign and one symptom of volume overload (pedal edema, crackles, consistent chest X-ray, increased left ventricular end-diastolic diameter, or elevated BNP level) is required \[46\].

Eligibility Criteria:
Inclusion Criteria:

* Previously unrecognized OSA with an Apnea Hypopnea Index (AHI) \> 15 events per hour on the attended in-hospital sleep study. Patients with apnea index of less than 5 events / hour are excluded (see design consideration for rationale)
* Projected length of stay 3 days or more on the morning following the cardio-respiratory sleep study
* Ongoing or planned targeted treatment for heart failure including one of the following: IV diuretics, IV infusion of inotropes or vasodilators, or planned revascularization, or device therapy

Exclusion Criteria:

* Patients who are already diagnosed with OSA
* Patients with Central Sleep Apnea
* Patients with diastolic only heart failure
* Cardiogenic shock and hemodynamic instability with MAP less than 55 mmHg off vasopressors, or concurrently on vasopressor treatment, left ventricular assist devices, or intra-aortic Balloon Pump. Inotropic agents will not constitute an exclusion criterion. Patients will be eligible once off vasopressors.
* Acute respiratory failure or insufficiency defined by P/F (PaO2/FIO2) ratio less than 250, or FIO2 requirement more than 50%
* Overt neurological deficit
* Renal failure requiring renal replacement therapy; Patients will not be excluded if they were undergoing ultra-filtration for volume removal
* Patients scheduled for procedures that will interfere with post randomization measurement: This includes scheduled coronary bypass surgery, or expected left ventricular assist device placement.
* Patients who arrived from a long-term care facility or expected to be discharged to one; and patients who have very poor functional outcome precluding ability to use the CPAP device independently.
* Patients on long term or "bridging" inotropic infusion, or short life expectancy due to concomitant illness