Abstract 18390: Influence of Fluid Retention on Pulmonary Function Testing in Heart Failure.
Background: Chronic obstructive pulmonary disease (COPD) and heart failure (HF) share typical signs and symptoms. Pulmonary congestion in HF may cause an obstructive ventilatory disorder (OVD) in pulmonary function testing (PFT) which may frequently misinterpreted as COPD. We investigated the influence of clinically apparent fluid retention on PFT in HF.
Methods: PFT was performed during hospitalization due to systolic HF (left ventricular ejection fraction (LVEF) ≤40%), and repeated 6 months after discharge. Fluid retention was assessed clinically. A history of COPD was assumed if stated in medical records or if patients were on bronchodilator therapy. OVD was defined by the ratio of 1sec-forced expiratory volume (FEV1) and forced vital capacity (FVC) <0.7.
Results: We analyzed 277 subjects (80% men, 66±12 years, LVEF 32±8%, NYHA class I-IV 1/61/37/1%). COPD was reported in 25% (69/277), and treated in 87% of those (60/69). Fluid retention was apparent in 44% (123/277) at in-hospital PFT, but only in 27% (75/277) at 6 months follow-up. In-hospital PFT revealed restrictive and obstructive alterations: FVC 85±21, FEV1 84±23% of predicted value and FEV1/FVC 73±16 %. In-hospital fluid retention was associated with age (69±10 vs 63±13 years), higher NYHA class (2.5±0.5 vs 2.3±0.5), lower FVC, FEV1, FEV1/FVC (78±19 vs 91±22, 78±22 vs 88±23% of predicted value and 71±17 vs 75±15%) and more frequent OVD (51 vs 33% all p<0.01). Six months after discharge, PFT revealed improved mean values for FVC (90±21%), FEV1 (91±24%) and FEV1/FVC (79±11%). In patients with initial fluid retention, median changes in FEV1 and FEV1/FVC were more pronounced (+11% vs +4% for both variables; p<0.01 for both) while FVC improvement was comparable to those without initial fluid retention. According to PFT 6 months after discharge, OVD was only found in 14% (40/277). COPD was excluded in 68% (47/69) of patients with reported COPD and in 65% (39/60) of those on bronchodilator therapy.
Conclusion: Fluid retention in HF significantly affects results of PFT. As a consequence, COPD is often overdiagnosed (68%) and overtreated (65%). A correct differential diagnosis requires serial measurements after cardiac recompensation.
- © 2010 by American Heart Association, Inc.