Obstructive sleep apnea (OSA) is characterized by recurrent complete and partial upper airway obstructive events, resulting in intermittent hypoxemia, autonomic fluctuation, and sleep fragmentation. Approximately 34% and 17% of middle-aged men and women, respectively, meet the diagnostic criteria for OSA. Sleep disturbances are common and underdiagnosed among middle-aged and older adults, and the prevalence varies by race/ethnicity, sex, and obesity status. OSA prevalence is as high as 40% to 80% in patients with hypertension, heart failure, coronary artery disease, pulmonary hypertension, atrial fibrillation, and stroke. Despite its high prevalence in patients with heart disease and the vulnerability of cardiac patients to OSA-related stressors and adverse cardiovascular outcomes, OSA is often underrecognized and undertreated in cardiovascular practice. We recommend screening for OSA in patients with resistant/poorly controlled hypertension, pulmonary hypertension, and recurrent atrial fibrillation after either cardioversion or ablation. In patients with New York Heart Association class II to IV heart failure and suspicion of sleep-disordered breathing or excessive daytime sleepiness, a formal sleep assessment is reasonable. In patients with tachy-brady syndrome or ventricular tachycardia or survivors of sudden cardiac death in whom sleep apnea is suspected after a comprehensive sleep assessment, evaluation for sleep apnea should be considered. After stroke, clinical equipoise exists with respect to screening and treatment. Patients with nocturnally occurring angina, myocardial infarction, arrhythmias, or appropriate shocks from implanted cardioverter-defibrillators may be especially likely to have comorbid sleep apnea. All patients with OSA should be considered for treatment, including behavioral modifications and weight loss as indicated. Continuous positive airway pressure should be offered to patients with severe OSA, whereas oral appliances can be considered for those with mild to moderate OSA or for continuous positive airway pressure–intolerant patients. Follow-up sleep testing should be performed to assess the effectiveness of treatment.
Attempts at developing novel therapeutic agents for acute heart failure (AHF) over the past two decades have been marked by disappointment. Relaxin is a human peptide hormone believed to mediate many adaptive haemodynamic changes that occur during pregnancy. Because these effects may be useful for treating AHF, a recombinant version of human relaxin-2, serelaxin, has been developed as a novel therapeutic agent. Studies have confirmed serelaxin's haemodynamic effects of decreasing pulmonary and systemic resistance and increasing renal blood flow. A 1161-patient, placebo-controlled Phase III trial, RELAX-AHF, demonstrated significant improvement in symptoms, reduced worsening of heart failure, decreased hospital length of stay and increased 180-day survival after index hospitalisation. Additional Phase III trials (RELAX-AHF-2; RELAX-AHF-ASIA) are underway to further evaluate the efficacy of serelaxin in patients with AHF. This article will review the physiological function, mechanism of action, clinical trial results and future directions of serelaxin in the treatment of AHF.
In stable CAD, echo-estimated leftward and rightward shifts in the LV-EDPVR are associated with HF and CV death. The loss of these associations after adjustment for N-terminal pro-brain natriuretic peptide level suggests that echo-estimated LV-EDPVR captures changes in LV filling pressure at any given LV end-diastolic volume.
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