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Abstract
Introduction A typical patient, with hypertension, diabetes or obesity, presenting with breathlessness and fatigue may be referred for cardiovascular review, but likewise for sleep apnoea assessment. In the symptomatic patient, current guidelines indicate the use of natriuretic peptides and echocardiography for diagnostic work-up of heart failure. We aimed to determine the prevalence of heart failure with preserved ejection fraction (HFpEF) in patients referred for sleep apnoea testing.
Methods Patients scheduled for a diagnostic respiratory polygraphy were recruited as part of an ongoing prospective, observational study. Exclusion criteria included age <40 years, previous diagnosis of heart failure or treated SDB. Each patient was assessed with a clinical cardiovascular assessment, electrocardiogram, N-terminal pro-brain natriuretic peptide (NT-proBNP) and echocardiogram.
Results Preliminary data for 40 patients are presented in this abstract. Hypertension, obesity and diabetes were highly prevalent (Table 1). Sleep apnoea was identified in 27 patients (68%). 63% were breathless and 30% had peripheral oedema. All were in sinus rhythm. NT-proBNP levels ranged between 5–483 pg/ml. Nine patients (22.5%) had NT-proBNP levels above 125 pg/ml, the NICE recommended threshold for echocardiography referral. Of these, six patients (65%) had normal diastolic and systolic function. One patient had definite diastolic dysfunction by ASE and EACI 2016 criteria. One patient had severe septal left ventricular hypertrophy. No significant correlation between NT-proBNP and SDB severity (apnoea-hypopnoea index) was seen (r=−0.08, p=0.961).
Abstract 40 Table 1 Baseline characteristics
Conclusion Cardiovascular risk factors are highly prevalent in patients referred for sleep apnoea assessment. However, among this population HFpEF is uncommon. Given the considerable proportion of false positive NT-proBNP levels, biomarker screening for heart failure in these patients may have limited benefit. The value of echocardiography, however, remains to be determined. We wish to present our full study results at BCS 2018.
Abstract 40 Figure 1 NT-proBNP levels in patients tested for sleep apnoea