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Published on: January 29, 2011
Prognostic value of resting end-tidal carbon dioxide in patients with heart failure
Ross Arena1, Mary Ann Peberdy, Jonathan Myers
1Department of Physical Therapy, Box 980224, Virginia Commonwealth University, Health Sciences Campus, Richmond, Virginia, 23298-0224, USA. raarena@vcu.edu
Insights
Resting end-tidal carbon dioxide partial pressure (PETCO2) can predict cardiac events in heart failure (HF) patients. This simple measure, obtained before cardiopulmonary exercise testing (CPET), adds prognostic value to established HF assessments.
Area of Science:
- Cardiology
- Pulmonology
- Exercise Physiology
Background:
- Cardiopulmonary exercise testing (CPET) variables are crucial for prognosis in heart failure (HF).
- Assessing resting end-tidal carbon dioxide partial pressure (PETCO2) as a predictor of cardiac events in HF patients is important.
Purpose of the Study:
- To evaluate the predictive capability of resting PETCO2 for cardiac-related events in patients with HF.
- To determine if resting PETCO2 provides prognostic information independently or in conjunction with other CPET variables.
Main Methods:
- 121 compensated HF patients underwent outpatient CPET.
- Resting PETCO2 was measured before CPET; peak oxygen consumption (VO2) and VE/VCO2 slope were also recorded.
- Cox regression analyses (univariate and multivariate) were used to assess predictors of cardiac events.
Main Results:
- Resting PETCO2, peak VO2, and VE/VCO2 slope were all significant univariate predictors of cardiac events.
- Multivariate analysis showed resting PETCO2 added prognostic value to the VE/VCO2 slope (p=0.04).
- Peak VO2 did not provide additional prognostic value when combined with VE/VCO2 slope.
Conclusions:
- Resting PETCO2 is a valuable prognostic marker in HF patients.
- This simple, non-invasive measure can be obtained during routine evaluations.
- Resting PETCO2 offers independent prognostic value and enhances established CPET-based predictions.
Background:
Cardiopulmonary exercise testing (CPET) variables provide valuable prognostic information in the heart failure (HF) population. The purpose of the present study is to assess the ability of resting end-tidal carbon dioxide partial pressure (PETCO2) to predict cardiac-related events in patients with HF.
Methods:
121 subjects diagnosed with compensated HF underwent CPET on an outpatient basis. Mean age and ejection fraction were 49.3 years (+/-14.7) and 28.4% (+/-13.4), respectively. Resting P(ET)CO2 was determined immediately prior to the exercise test in the seated position. Peak oxygen consumption (VO2) and the minute ventilation-carbon dioxide production (VE/VCO2) slope were also acquired during CPET.
Results:
There were 41 cardiac-related hospitalizations and 9 cardiac-related deaths in the year following CPET. Mean resting P(ET)CO2, peak VO2 and VE/VCO2 slope were 34.1 mmHg (+/-4.6), 14.5 ml*kg(-1)*min(-1) (+/-5.1) and 35.9 (+/-8.7) respectively. Univariate Cox regression analysis revealed that resting P(ET)CO2 (Chi-square=28.4, p<0.001), peak VO2 (Chi-square=21.6, p<0.001) and VE/VCO2 slope (Chi-square=54.9, p<0.001) were all significant predictors of cardiac related events. Multivariate Cox regression analysis revealed resting P(ET)CO2 added to the prognostic value of VE/VCO2 slope in predicting cardiac related events (residual Chi-square=4.4, p=0.04). Peak VO2 did not add additional value and was removed (residual Chi-square=3.2, p=0.08).
Conclusions:
These results indicate a resting ventilatory expired gas variable possesses prognostic value independently and in combination with an established prognostic marker from the CPET. Resting P(ET)CO2 may therefore be a valuable objective measure to obtain during both non-exercise and exercise evaluations in patients with HF.
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