title: Peak cardiac power measured noninvasively with a bioreactance technique is a predictor of adverse outcomes in patients with advanced heart failure.
abstract: Peak oxygen consumption (VO(2) ) during cardiopulmonary exercise testing (CPET) is a powerful predictor of survival, providing an indirect assessment of cardiac output (CO). Noninvasive indices of CO derived from bioreactance methodology would add significantly to peak VO(2) as a means of risk-stratifying patients with heart failure. In this study, 127 patients (53 ± 14 years of age, 66% male) with heart failure and an average ejection fraction of 31% ± 15% underwent symptom-limited CPET using a bicycle ergometer while measuring CO noninvasively by a bioreactance technique. Peak cardiac power was derived from the product of the peak mean arterial blood pressure and CO divided by 451. Follow-up averaged 404 ± 179 days (median, 366 days) to assess endpoints including death (n=3), heart transplant (n=10), or left ventricular assisted device implantation (n=2). Peak VO(2) and peak power had similar areas under the curve (0.77 and 0.76), which increased to 0.83 when combined. Kaplan-Meier cumulative survival curves demonstrated different outcomes in the subgroup with a VO(2) <14 mL/kg/min when stratified by a cardiac power above or below 1.5 W (92.2% vs 82.1% at 1 year and 81.6% vs 58.3% at last follow-up, P=.02 by log-rank test). Among patients with heart failure, peak cardiac power measured with bioreactance methodology and peak VO(2) had similar associations with adverse outcomes and peak power added independent prognostic information to peak VO(2) in those with advanced disease (eg, VO(2) <14 mL/kg/min).
authors.affiliation: Columbia University Medical Center, New York, NY 10032, USA.
authors.forename: Hannah
authors.initials: H
authors.lastname: Rosenblum
authors.forename: Stephen
authors.initials: S
authors.lastname: Helmke
authors.forename: Paula
authors.initials: P
authors.lastname: Williams
authors.forename: Sergio
authors.initials: S
authors.lastname: Teruya
authors.forename: Margaret
authors.initials: M
authors.lastname: Jones
authors.forename: Daniel
authors.initials: D
authors.lastname: Burkhoff
authors.forename: Donna
authors.initials: D
authors.lastname: Mancini
authors.forename: Mathew S
authors.initials: MS
authors.lastname: Maurer
mesh_terms: D001642:Bicycling; D002303:Cardiac Output, Low / Q000175:diagnosis* / Q000503:physiopathology; D018450:Disease Progression; D006804:Ergonomics; D005080:Exercise Test / Q000295:instrumentation / Q000379:methods*; D017079:Exercise Tolerance / Q000502:physiology*; D005260:Female; D006305:Health Status Indicators; D006333:Heart Failure / Q000175:diagnosis* / Q000401:mortality / Q000503:physiopathology; D006439:Hemodynamics; D006801:Humans; D053208:Kaplan-Meier Estimate; D008297:Male; D008875:Middle Aged; D009518:New York; D010101:Oxygen Consumption / Q000502:physiology*; D011379:Prognosis; D011446:Prospective Studies; D012372:ROC Curve; D018570:Risk Assessment; D013223:Statistics as Topic; D013318:Stroke Volume; D016277:Ventricular Function, Left