Using the Lower Limit of Normal Instead of the Conventional Cutoff Values to Define Predictors of Pulmonary Function Impairment in Subjects With Chronic Heart Failure

Abstract

BACKGROUND: Using the newer lower limit of normal criterion instead of the conventional cutoff values to define pulmonary function abnormalities may result in different predictors of pulmonary function impairment in patients with heart failure. Therefore, we assessed predictors of pulmonary function impairment in subjects with chronic heart failure according to the lower limit of normal in comparison with conventional cutoff values. METHODS: In this prospective cross-sectional study, 164 chronic heart failure subjects (age 68 ؎ 10 y, 78% men, 88% New York Heart Association class I-II) with left ventricular ejection fraction <40% underwent pulmonary function tests. Predictors of pulmonary function impairment were assessed using the lower limit of normal and conventional cutoff values (ie, 80% predicted value and the fixed ratio of FEV 1 /FVC <0.7). RESULTS: The lower limit of normal criterion identified an extra independent predictor of diffusion impairment compared with the 80% predicted value; in addition to body mass index, pack-years, and alveolar volume, female sex also turned out to be an independent predictor. A smoking history of >10 pack-years was a significant predictor of diffusion impairment and airway obstruction using the lower limit of normal criterion but not using the conventional cutoff values. However, lowering the cutoff points of conventional criteria to match the more stringent lower limit of normal and thus avoid overdiagnosis of diffusion impairment and airway obstruction in the elderly produced similar results as the lower limit of normal. CONCLUSIONS: The lower limit of normal identifies more predictors of diffusion impairment and airway obstruction compared with conventional cutoff values in subjects with chronic heart failure with left ventricular systolic dysfunction. However, lowering the conventional cutoff points yielded similar results as the lower limit of normal. (ClinicalTrials.gov registration NCT01429376.) Key words: Chronic heart failure, conventional cutoff values, lower limit of normal, predictors, pulmonary function impairment. [Respir Care 2016;61(2):173-183.

What can we learn from pulmonary function testing in heart failure?

“…Combining spirometry, D LCO , and natriuretic peptide levels may generally allow differentiation between heart and pulmonary disorders in patients with dyspnoea ( Table ). However, permanent damage to the alveolar‐capillary membrane might be present in patients with chronic ‘dry lung HF’ and determine a reduction in D LCO , which is independent of pulmonary congestion, and/or COPD . In addition, because ‘wet lung HF’ may present a mixed obstructive/restrictive spirometric pattern, determination of the coexistence or the severity of COPD should wait until HF is optimally treated .…”

Insights to correlations and discrepancies between impaired lung function and heart failure in Eisenmenger patients

“…Gas diffusion impairment in these patients could be due to a reduction in pulmonary capillary blood volume and pulmonary membrane diffusion capacity as a consequence of increased pulmonary vascular resistance, reduced cardiac output and endothelial cell proliferation. 11,26…”

“…Gas diffusion impairment in these patients could be due to a reduction in pulmonary capillary blood volume and pulmonary membrane diffusion capacity as a consequence of increased pulmonary vascular resistance, reduced cardiac output and endothelial cell proliferation. 11,26 Elevation of cardiac biomarker BNP is associated with poorer prognosis and disease progression in patients with CHD, including ES. 28 S ¸ahingo¨zlu¨et al confirmed that plasma BNP levels were affected much more in cardiac pathology rather than in the lung disease, 29 but there is a lack of studies about BNP association with lung function parameters.…”

Cardiovascular diseases or type 2 diabetes mellitus and chronic airway diseases: mutual pharmacological interferences

“… 62 In effect, patients with HF may develop diffusion impairment and airway obstruction even when they are stable and uncongested and do not have CAD. 63 Airway obstruction in these patients has been associated with increased airway wall thickness caused by bronchial mucosal enlargement, peribronchial edema and fibrosis, parasympathetic-mediated bronchoconstriction, and alveolar fluid retention. 64 Reduced air trapping combined with reduced compression of the pulmonary microcirculation mediates the effects of bronchodilators on cardiac filling caused by improved perfusion.…”