title: Does Exercise Ventilatory Inefficiency Predict Poor Outcome in Heart Failure Patients With COPD?
abstract: OBJECTIVE
  To investigate whether the opposite effects of heart failure (HF) and chronic obstructive pulmonary disease (COPD) on exercise ventilatory inefficiency (minute ventilation [(Equation is included in full-text article.)E]-carbon dioxide output [(Equation is included in full-text article.)CO2] relationship) would negatively impact its prognostic relevance.
  
  
  METHODS
  After treatment optimization and an incremental cardiopulmonary exercise test, 30 male patients with HF-COPD (forced expiratory volume in 1 second [FEV1] = 57% ± 17% predicted, ejection fraction = 35% ± 6%) were prospectively followed up during 412 ± 261 days for major cardiac events.
  
  
  RESULTS
  Fourteen patients (46%) had a negative outcome. Patients who had an event had lower echocardiographically determined right ventricular fractional area change (RVFAC), greater ventilatory inefficiency (higher (Equation is included in full-text article.)E/(Equation is included in full-text article.)CO2 nadir), and lower end-tidal CO2 (PETCO2) (all P < .05). Multivariate Cox models revealed that (Equation is included in full-text article.)E/(Equation is included in full-text article.)CO2 nadir >36, ΔPETCO2(PEAK-REST)≥2 mm Hg, and PETCO2PEAK≤33 mm Hg added prognostic value to RVFAC≤45%. Kaplan-Meyer analyses showed that although 18% of patients with RVFAC>45% had a major cardiac event after 1 year, no patient with RVFAC>45% and (Equation is included in full-text article.)E/(Equation is included in full-text article.)CO2 nadir ≤36 (or PETCO2PEAK>33 mm Hg) had a negative event. Conversely, although 69% of patients with RVFAC≤45% had a major cardiac event after 1 year, all patients with RVFAC≤45% and ΔPETCO2(PEAK-REST)≥2 mm Hg had a negative event.
  
  
  CONCLUSIONS
  Ventilatory inefficiency remains a powerful prognostic marker in HF despite the presence of mechanical ventilatory constraints induced by COPD. If these preliminary findings are confirmed in larger studies, optimal thresholds for outcome prediction are likely greater than those traditionally recommended for HF patients without COPD.
authors: Divisions of Respirology (Drs Alencar, Arbex, and Neder, Mss Souza and Sperandio, and Messrs Rocha and Hirai) and Cardiology (Drs Mancuso and Almeida), Federal University of Sao Paulo, Brazil; Respiratory Investigation Unit and Laboratory of Clinical Exercise Physiology, Queen's University and Kingston General Hospital, Kingston, Ontario, Canada (Mr Hirai and Drs O'Donnel and Neder); Department of Physiotherapy, Federal University of Sao Carlos, Brazil (Mss Mazzuco and Borghi-Silva); and Division of Respirology, Federal University of Rio Grande do Sul, Porto Alegre, Brazil (Dr Berton).
authors: Maria Clara
authors: MC
authors: Alencar
authors: Flavio F
authors: FF
authors: Arbex
authors: Aline
authors: A
authors: Souza
authors: Adriana
authors: A
authors: Mazzuco
authors: Priscila A
authors: PA
authors: Sperandio
authors: Alcides
authors: A
authors: Rocha
authors: Daniel M
authors: DM
authors: Hirai
authors: Frederico
authors: F
authors: Mancuso
authors: Danilo C
authors: DC
authors: Berton
authors: Audrey
authors: A
authors: Borghi-Silva
authors: Dirceu
authors: D
authors: Almeida
authors: Denis E
authors: DE
authors: OʼDonnel
authors: J Alberto
authors: JA
authors: Neder
mesh_terms: D000368:Aged; D017079:Exercise Tolerance / Q000502:physiology*; D005500:Follow-Up Studies; D006333:Heart Failure / Q000150:complications* / Q000503:physiopathology / Q000628:therapy; D006801:Humans; D008168:Lung / Q000503:physiopathology*; D008297:Male; D063868:Patient Outcome Assessment; D011446:Prospective Studies; D029424:Pulmonary Disease, Chronic Obstructive / Q000150:complications* / Q000503:physiopathology / Q000628:therapy; D012123:Pulmonary Ventilation / Q000502:physiology*; D012129:Respiratory Function Tests; D012720:Severity of Illness Index