title: Targeting of high peak respiratory exchange ratio is safe and enhances the prognostic power of peak oxygen uptake for heart failure patients.
abstract: BACKGROUND
  Peak oxygen uptake (V̇O2) and ventilatory efficiency (V̇E/V̇CO2slope) measured on cardiopulmonary exercise testing (CPX) are prognostic indicators in heart failure (HF) patients, but peak V̇O2is influenced by patient effort. In CPX targeting a peak respiratory exchange ratio (pRER; an objective index of effort adequacy) higher than the commonly recommended level, we assessed the safety and prognostic value of CPX parameters compared with non-CPX parameters. METHODS AND RESULTS: We studied 283 consecutive HF patients with left ventricular ejection fraction (LVEF) ≤45% (mean, 26.3%) who underwent CPX targeting pRER >1.20. The attained pRER (mean, 1.26) was consistently high irrespective of LVEF, and there was no major exercise-related adverse event. The composite of all-cause death or HF hospitalization occurred in 111 patients (39%) during a median follow-up of 47 months. Among well-known prognostic markers, peak V̇O2was the most powerful predictor of outcome as both a continuous and an optimal dichotomous variable, followed by V̇E/V̇CO2slope. On multivariate analysis, peak V̇O2was a significant independent predictor, whereas V̇E/V̇CO2slope, B-type natriuretic peptide, and LVEF were not.
  
  
  CONCLUSIONS
  In CPX targeting pRER >1.20 for HF patients, peak V̇O2is the most powerful among well-known predictors, without an increased risk of exercise-related events. These findings advocate a high target pRER in CPX even in advanced HF.
authors: Department of Cardiovascular Medicine, National Cerebral and Cardiovascular Center.
authors: Michio
authors: M
authors: Nakanishi
authors: Hiroshi
authors: H
authors: Takaki
authors: Reon
authors: R
authors: Kumasaka
authors: Tetsuo
authors: T
authors: Arakawa
authors: Teruo
authors: T
authors: Noguchi
authors: Masaru
authors: M
authors: Sugimachi
authors: Yoichi
authors: Y
authors: Goto
mesh_terms: D000368:Aged; D018572:Disease-Free Survival; D005080:Exercise Test; D005260:Female; D006333:Heart Failure / Q000097:blood / Q000401:mortality / Q000503:physiopathology; D006801:Humans; D008297:Male; D008875:Middle Aged; D020097:Natriuretic Peptide, Brain / Q000097:blood; D010100:Oxygen / Q000097:blood*; D010101:Oxygen Consumption; D012119:Respiration; D012307:Risk Factors; D013318:Stroke Volume; D015996:Survival Rate
chemical_list: D020097:Natriuretic Peptide, Brain; D010100:Oxygen