title: Role of right ventricle and dynamic pulmonary hypertension on determining ΔVO2/ΔWork Rate flattening: insights from cardiopulmonary exercise test combined with exercise echocardiography.
abstract: BACKGROUND
  Several cardiovascular diseases are characterized by an impaired O2 kinetic during exercise. The lack of a linear increase of Δoxygen consumption (VO2)/ΔWork Rate (WR) relationship, as assessed by expired gas analysis, is considered an indicator of abnormal cardiovascular efficiency. We aimed at describing the frequency of ΔVO2/ΔWR flattening in a symptomatic population of cardiac patients, characterizing its functional profile, and testing the hypothesis that dynamic pulmonary hypertension and right ventricular contractile reserve play a major role as cardiac determinants.
  
  
  RESULTS
  We studied 136 patients, with different cardiovascular diseases, referred for exertional dyspnoea. Cardiopulmonary exercise test combined with simultaneous exercise echocardiography was performed using a symptom-limited protocol. ΔVO2/ΔWR flattening was observed in 36 patients (group A, 26.5% of population) and was associated with a globally worse functional profile (reduced peak VO2, anaerobic threshold, O2 pulse, impaired VE/VCO2). At univariate analysis, exercise ejection fraction, exercise mitral regurgitation, rest and exercise tricuspid annular plane systolic excursion, exercise systolic pulmonary artery pressure, and exercise cardiac output were all significantly (P<0.05) impaired in group A. The multivariate analysis identified exercise systolic pulmonary artery pressure (odds ratio, 1.06; confidence interval, 1.01-1.11; P=0.01) and exercise tricuspid annular plane systolic excursion (odds ratio, 0.88; confidence interval, 0.80-0.97; P=0.01) as main cardiac determinants of ΔVO2/ΔWR flattening; female sex was strongly associated (odds ratio, 6.10; confidence interval, 2.11-17.7; P<0.01).
  
  
  CONCLUSIONS
  In patients symptomatic for dyspnea, the occurrence of ΔVO2/ΔWR flattening reflects a significantly impaired functional phenotype whose main cardiac determinants are the excessive systolic pulmonary artery pressure increase and the reduced peak right ventricular longitudinal systolic function.
authors: From the Heart Failure Unit, IRCCS Policlinico San Donato, University of Milano, Milano, Italy (F.B., G.G., M.P., V.D., E.A., M.G.); and Unit of Biostatistics and Clinical Epidemiology, Department of Public Health, Experimental and Forensic Medicine, University of Pavia, Pavia, Italy (M.G., S.V.). francescobandera@gmail.com.
authors: Francesco
authors: F
authors: Bandera
authors: From the Heart Failure Unit, IRCCS Policlinico San Donato, University of Milano, Milano, Italy (F.B., G.G., M.P., V.D., E.A., M.G.); and Unit of Biostatistics and Clinical Epidemiology, Department of Public Health, Experimental and Forensic Medicine, University of Pavia, Pavia, Italy (M.G., S.V.).
authors: Greta
authors: G
authors: Generati
authors: From the Heart Failure Unit, IRCCS Policlinico San Donato, University of Milano, Milano, Italy (F.B., G.G., M.P., V.D., E.A., M.G.); and Unit of Biostatistics and Clinical Epidemiology, Department of Public Health, Experimental and Forensic Medicine, University of Pavia, Pavia, Italy (M.G., S.V.).
authors: Marta
authors: M
authors: Pellegrino
authors: From the Heart Failure Unit, IRCCS Policlinico San Donato, University of Milano, Milano, Italy (F.B., G.G., M.P., V.D., E.A., M.G.); and Unit of Biostatistics and Clinical Epidemiology, Department of Public Health, Experimental and Forensic Medicine, University of Pavia, Pavia, Italy (M.G., S.V.).
authors: Valeria
authors: V
authors: Donghi
authors: From the Heart Failure Unit, IRCCS Policlinico San Donato, University of Milano, Milano, Italy (F.B., G.G., M.P., V.D., E.A., M.G.); and Unit of Biostatistics and Clinical Epidemiology, Department of Public Health, Experimental and Forensic Medicine, University of Pavia, Pavia, Italy (M.G., S.V.).
authors: Eleonora
authors: E
authors: Alfonzetti
authors: From the Heart Failure Unit, IRCCS Policlinico San Donato, University of Milano, Milano, Italy (F.B., G.G., M.P., V.D., E.A., M.G.); and Unit of Biostatistics and Clinical Epidemiology, Department of Public Health, Experimental and Forensic Medicine, University of Pavia, Pavia, Italy (M.G., S.V.).
authors: Maddalena
authors: M
authors: Gaeta
authors: From the Heart Failure Unit, IRCCS Policlinico San Donato, University of Milano, Milano, Italy (F.B., G.G., M.P., V.D., E.A., M.G.); and Unit of Biostatistics and Clinical Epidemiology, Department of Public Health, Experimental and Forensic Medicine, University of Pavia, Pavia, Italy (M.G., S.V.).
authors: Simona
authors: S
authors: Villani
authors: From the Heart Failure Unit, IRCCS Policlinico San Donato, University of Milano, Milano, Italy (F.B., G.G., M.P., V.D., E.A., M.G.); and Unit of Biostatistics and Clinical Epidemiology, Department of Public Health, Experimental and Forensic Medicine, University of Pavia, Pavia, Italy (M.G., S.V.).
authors: Marco
authors: M
authors: Guazzi
mesh_terms: D000368:Aged; D002302:Cardiac Output; D015150:Echocardiography, Doppler / Q000379:methods; D025401:Echocardiography, Stress / Q000379:methods*; D015444:Exercise / Q000523:psychology*; D005080:Exercise Test; D005260:Female; D005500:Follow-Up Studies; D006333:Heart Failure / Q000150:complications / Q000503:physiopathology*; D006352:Heart Ventricles / Q000000981:diagnostic imaging / Q000503:physiopathology*; D006801:Humans; D006976:Hypertension, Pulmonary / Q000150:complications / Q000503:physiopathology*; D008297:Male; D008875:Middle Aged; D010101:Oxygen Consumption; D011379:Prognosis; D012189:Retrospective Studies; D016278:Ventricular Function, Right / Q000502:physiology*
keywords: cardiovascular diseases; echocardiography; exercise; hypertension, pulmonary; right heart failure