title: Heart Failure Impairs Muscle Blood Flow and Endurance Exercise Tolerance in COPD.
abstract: Heart failure, a prevalent and disabling co-morbidity of COPD, may impair cardiac output and muscle blood flow thereby contributing to exercise intolerance. To investigate the role of impaired central and peripheral hemodynamics in limiting exercise tolerance in COPD-heart failure overlap, cycle ergometer exercise tests at 20% and 80% peak work rate were performed by overlap (FEV1 = 56.9 ± 15.9% predicted, ejection fraction = 32.5 ± 6.9%; N = 16), FEV1-matched COPD (N = 16), ejection fraction-matched heart failure patients (N = 15) and controls (N = 12). Differences (Δ) in cardiac output (impedance cardiography) and vastus lateralis blood flow (indocyanine green) and deoxygenation (near-infrared spectroscopy) between work rates were expressed relative to concurrent changes in muscle metabolic demands (ΔO2 uptake). Overlap patients had approximately 30% lower endurance exercise tolerance than COPD and heart failure (p < 0.05). ΔBlood flow was closely proportional to Δcardiac output in all groups (r = 0.89-0.98; p < 0.01). Overlap showed the largest impairments in Δcardiac output/ΔO2 uptake and Δblood flow/ΔO2 uptake (p < 0.05). Systemic arterial oxygenation, however, was preserved in overlap compared to COPD. Blunted limb perfusion was related to greater muscle deoxygenation and lactate concentration in overlap (r = 0.78 and r = 0.73, respectively; p < 0.05). ΔBlood flow/ΔO2 uptake was related to time to exercise intolerance only in overlap and heart failure (p < 0.01). In conclusion, COPD and heart failure add to decrease exercising cardiac output and skeletal muscle perfusion to a greater extent than that expected by heart failure alone. Treatment strategies that increase muscle O2 delivery and/or decrease O2 demand may be particularly helpful to improve exercise tolerance in COPD patients presenting heart failure as co-morbidity.
authors.affiliation: a Pulmonary Function and Clinical Exercise Physiology Unit (SEFICE), Respiratory Division , Federal University of São Paulo (UNIFESP) , São Paulo , Brazil.
authors.forename: Mayron F
authors.initials: MF
authors.lastname: Oliveira
authors.affiliation: a Pulmonary Function and Clinical Exercise Physiology Unit (SEFICE), Respiratory Division , Federal University of São Paulo (UNIFESP) , São Paulo , Brazil.
authors.forename: Flavio F
authors.initials: FF
authors.lastname: Arbex
authors.affiliation: a Pulmonary Function and Clinical Exercise Physiology Unit (SEFICE), Respiratory Division , Federal University of São Paulo (UNIFESP) , São Paulo , Brazil.
authors.forename: Maria Clara
authors.initials: MC
authors.lastname: Alencar
authors.affiliation: a Pulmonary Function and Clinical Exercise Physiology Unit (SEFICE), Respiratory Division , Federal University of São Paulo (UNIFESP) , São Paulo , Brazil.
authors.forename: Aline
authors.initials: A
authors.lastname: Souza
authors.affiliation: a Pulmonary Function and Clinical Exercise Physiology Unit (SEFICE), Respiratory Division , Federal University of São Paulo (UNIFESP) , São Paulo , Brazil.
authors.forename: Priscila A
authors.initials: PA
authors.lastname: Sperandio
authors.affiliation: a Pulmonary Function and Clinical Exercise Physiology Unit (SEFICE), Respiratory Division , Federal University of São Paulo (UNIFESP) , São Paulo , Brazil.
authors.forename: Wladimir M
authors.initials: WM
authors.lastname: Medeiros
authors.affiliation: b Department of Physiotherapy , Federal University of São Carlos (UFSCAR) , São Carlos , Brazil.
authors.forename: Adriana
authors.initials: A
authors.lastname: Mazzuco
authors.affiliation: b Department of Physiotherapy , Federal University of São Carlos (UFSCAR) , São Carlos , Brazil.
authors.forename: Audrey
authors.initials: A
authors.lastname: Borghi-Silva
authors.affiliation: a Pulmonary Function and Clinical Exercise Physiology Unit (SEFICE), Respiratory Division , Federal University of São Paulo (UNIFESP) , São Paulo , Brazil.
authors.forename: Luiz A
authors.initials: LA
authors.lastname: Medina
authors.affiliation: a Pulmonary Function and Clinical Exercise Physiology Unit (SEFICE), Respiratory Division , Federal University of São Paulo (UNIFESP) , São Paulo , Brazil.
authors.forename: Rita
authors.initials: R
authors.lastname: Santos
authors.affiliation: a Pulmonary Function and Clinical Exercise Physiology Unit (SEFICE), Respiratory Division , Federal University of São Paulo (UNIFESP) , São Paulo , Brazil.|c Laboratory of Clinical Exercise Physiology (LACEP), Division of Respiratory and Critical Care Medicine, Department of Medicine , Queen's University , Kingston , Canada.
authors.forename: Daniel M
authors.initials: DM
authors.lastname: Hirai
authors.affiliation: d Cardiology Division, Federal University of São Paulo (UNIFESP) , São Paulo , Brazil.
authors.forename: Frederico
authors.initials: F
authors.lastname: Mancuso
authors.affiliation: d Cardiology Division, Federal University of São Paulo (UNIFESP) , São Paulo , Brazil.
authors.forename: Dirceu
authors.initials: D
authors.lastname: Almeida
authors.affiliation: e Respiratory Investigation Unit (RIU), Division of Respiratory and Critical Care Medicine, Department of Medicine , Queen's University , Kingston , Canada.
authors.forename: Denis E
authors.initials: DE
authors.lastname: O'Donnell
authors.affiliation: a Pulmonary Function and Clinical Exercise Physiology Unit (SEFICE), Respiratory Division , Federal University of São Paulo (UNIFESP) , São Paulo , Brazil.|c Laboratory of Clinical Exercise Physiology (LACEP), Division of Respiratory and Critical Care Medicine, Department of Medicine , Queen's University , Kingston , Canada.
authors.forename: J Alberto
authors.initials: JA
authors.lastname: Neder
mesh_terms: D000368:Aged; D002302:Cardiac Output; D002307:Cardiography, Impedance; D016022:Case-Control Studies; D004452:Echocardiography; D005080:Exercise Test; D017079:Exercise Tolerance; D005541:Forced Expiratory Volume; D006333:Heart Failure / Q000150:complications / Q000503:physiopathology*; D006801:Humans; D008297:Male; D008875:Middle Aged; D010807:Physical Endurance; D029424:Pulmonary Disease, Chronic Obstructive / Q000150:complications / Q000503:physiopathology*; D052097:Quadriceps Muscle / Q000098:blood supply*; D012039:Regional Blood Flow; D019265:Spectroscopy, Near-Infrared; D013318:Stroke Volume
keywords: blood flow; chronic heart failure; exertion; microcirculation; skeletal muscle