Research Article. Characteristics of Sleep Apnea Assessed Before Discharge in Patients Hospitalized with Acute Heart Failure

Abstract

Objectives. Evaluation of the characteristics of sleep apnea (SA) in patients hospitalized with acute heart failure, considering that undiagnosed SA could contribute to early rehospitalization. Methods. 56 consecutive patients (13 women, 43 men, mean age 63.12 years) with acute heart failure, in stable condition, underwent nocturnal polygraphy before hospital discharge. The type and severity of SA was determined. Besides descriptive statistics, correlations between the severity of SA and clinical and paraclinical characteristics were also analyzed (t-test, chi-square test, significancy at alpha < 0.05). Results. 12 (21.4%) subjects were free of SA (AHI -apnea-hipopnea index <5/h), 15 (26.7%) had mild SA (AHI=5-14/h), 17 (30.3%) had moderate SA (AHI 15-30/h), and 12 (21.4 %) had severe SA (AHI>30/h). The apnea was predominantly obstructive (32 cases vs. 12 with central SA). Comparing the patients with mild or no SA with those with severe SA, we did not find statistically significant correlations (p>0.05) between the severity of SA and the majority of main clinical and paraclinical characteristicsage, sex, BMI, cardiac substrates of heart failure, comorbidities. Paradoxically, arterial hypertension (p=0.028) and atrial fibrillation (p=0.041) were significantly more prevalent in the group with mild or no SA. Conclusions. Before discharge, in the majority of patients hospitalized with acute heart failure moderate and severe SA is present, and is not related to the majority of patient related factors. Finding of significant SA in this setting is important, because its therapy could play an important role in preventing readmissions and improving prognosis. IntroductionThe relationship between sleep disordered breathing (SDB), represented by obstructive and central sleep apnea (SA), and cardiovascular diseases has been demonstrated in numerous studies. SDB confers an increased risk for cardiovascular complications and events, playing role in the pathophysiology of resistant hypertension, arrhythmias (from those benign to sudden cardiac death), myocardial ischemia, pulmonary hypertension and heart failure [1][2][3][4].The prevalence of symptomatic obstructive SA in the general population is about 4% in middle-aged men, and 2% in middle-aged women. SDB is common in heart failure (HF), being present in nearly one half of the patients, impairing both the quality of life and prognosis. The specific manifestation is central SA, which is directly related to the level of congestion and functional status [5][6][7].Acute HF is a common cause of hospitalizations in the course of HF, moreover, readmissions represent the most predictive factor for poor prognosis and increased mortality. Rehospitalizations within 30 days post-discharge are high, almost one third of patients being involved. The precipitating factors for these admissions are multiple, including cardiac and noncardiac conditions, like myocardial ischemia, arrhythmias, infections, treatment non-compliance, improper medications, etc., and, also, undiagnosed and/or untre...