Frequency and prognostic impact of mid-expiratory flow reduction in stable patients six months after hospitalisation for heart failure with reduced ejection fraction

Abstract

Aim: This study investigates the prevalence and prognostic impact of central and small airways obstruction (CAO and SAO) in patients with stable heart failure (HF).

Methods & results: Spirometry was performed in 585 outpatients (mean age 65±12years, 75% male) six months after hospitalisation for acute decompensation secondary to HF with ejection fraction <40%. We assessed forced expiratory volume in the first second (FEV1), forced vital capacity (FVC) and mid-expiratory flow (MEF) at 50% of FVC. CAO was defined by FEV1/FVC <0.7. SAO was defined by FEV1/FVC ≥0.7 plus MEF <60% of predicted value. CAO and SAO were excluded in 359 patients (61% of all). MEF <60% predicted was found in 226 patients (39% of all), among those 88 with CAO (15% of all) and 138 (24% of all) with SAO. During a twelve month follow-up, 42 patients (7.2%) died. Mortality rates of patients with CAO and SAO were comparable (12.5% and 10.9%, respectively, p=0.74), and both higher than in patients without airways obstruction (4.5%, both p<0.01). In univariable Cox regression analysis, both CAO and SAO were associated with 2-fold increased all-cause mortality risk (hazard ratios [95% confidence intervals]: 2.78 [1.33-6.19], p=0.007 and 2.51 [1.24-5.08], p=0.010, respectively). Adjustment for determinants of CAO and SAO, prognostic markers of heart failure and comorbidities attenuated the association of mortality with CAO but not with SAO.

Conclusions: SAO is more common than CAO and indicates an increased mortality risk in HF. Thus, reduced MEF may be a feature of patients at risk and merits special attention in HF management.

Keywords: Central airways obstruction; Mortality; Peripheral airways obstruction; Spirometry; Stable heart failure.