The Minute Ventilation/Carbon Dioxide Production Slope is Prognostically Superior to the Oxygen Uptake Efficiency Slope

Arena, Ross; Myers, Jonathan; Hsu, Leon; Peberdy, Mary Ann; Pinkstaff, Sherry; Bensimhon, Daniel; Chase, Paul; Vicenzi, Marco; Guazzi, Marco

doi:10.1016/j.cardfail.2007.03.004

« Previous Next »Journal of Cardiac Failure
Volume 13, Issue 6 , Pages 462-469, August 2007

The Minute Ventilation/Carbon Dioxide Production Slope is Prognostically Superior to the Oxygen Uptake Efficiency Slope

Ross Arena, PhD, PT
- From the Departments of Physical Therapy, Virginia Commonwealth University, Health Sciences Campus, Richmond, Virginia
- Reprint requests: Ross Arena, PhD, PT, Assistant Professor, Department of Physical Therapy, Box 980224, Virginia Commonwealth University, Health Sciences Campus, Richmond, VA 23298-0224.
Jonathan Myers, PhD
- VA Palo Alto Health Care System, Cardiology Division, Stanford University, Palo Alto, California
Leon Hsu, BS
- VA Palo Alto Health Care System, Cardiology Division, Stanford University, Palo Alto, California
Mary Ann Peberdy, MD
- Internal Medicine, Virginia Commonwealth University, Health Sciences Campus, Richmond, Virginia
Sherry Pinkstaff, BS
- From the Departments of Physical Therapy, Virginia Commonwealth University, Health Sciences Campus, Richmond, Virginia
Daniel Bensimhon, MD
- LeBauer Cardiovascular Research Foundation, Greensboro, North Carolina
Paul Chase, MEd
- LeBauer Cardiovascular Research Foundation, Greensboro, North Carolina
Marco Vicenzi, MS
- University of Milano, San Paolo Hospital, Cardiopulmonary Laboratory, Cardiology Division, Milano, Italy
Marco Guazzi, MD, PhD
- University of Milano, San Paolo Hospital, Cardiopulmonary Laboratory, Cardiology Division, Milano, Italy

Received 26 January 2007; received in revised form 20 February 2007; accepted 7 March 2007. published online 16 June 2007.

Richmond, Virginia; Palo Alto, California; Greensboro, North Carolina; Milan, Italy

Abstract

Background

Ventilatory efficiency, commonly assessed by the minute ventilation (VE)-carbon dioxide production (VCO₂) slope, has proven to be a strong prognostic marker in the heart failure (HF) population. Recently, the oxygen uptake efficiency slope (OUES) has demonstrated prognostic value, but additional comparisons to established cardiopulmonary exercise test (CPET) variables are required.

Methods and Results

A total of 341 subjects were diagnosed with HF participated in this analysis. The VE/VCO₂ slope and the OUES were calculated using 50% (VE/VCO₂ slope₅₀ or OUES₅₀) and 100% (VE/VCO₂ slope₁₀₀ or OUES₁₀₀) of the exercise data. Peak oxygen consumption (VO₂) was also determined. There were 47 major cardiac-related events during the 3-year tracking period. Receiver operating characteristic (ROC) curve analysis demonstrated the classification schemes for both VE/VCO₂ slope and OUES calculations as well as peak VO₂ were statistically significant (all areas under the ROC curve: ≥0.74, P < .001). Area under the ROC curve for the VE/VCO₂ slope₁₀₀ was, however, significantly greater than OUES₅₀, OUES₁₀₀, and peak VO₂ (P < .05).

Conclusions

Although the OUES was a significant predictor of mortality, the VE/VCO₂ slope maintained optimal prognostic value. An elevated VE/VCO₂ slope may be the single best indicator of increased risk for adverse events.

Key Words: Prognosis, ventilatory efficiency, expired gas analysis