Determining the Best Ventilatory Efficiency Measure to Predict Mortality in Patients with Heart Failure
| Autor: | Nicholas S. Clarke, Robert L. Bard, Timothy G. Egan, Brenda W. Gillespie, John M. Nicklas |
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| Rok vydání: | 2006 |
| Předmět: |
Adult
Male Pulmonary and Respiratory Medicine medicine.medical_specialty Heart disease Predictive Value of Tests Internal medicine Heart rate medicine Humans Respiratory exchange ratio Proportional Hazards Models Heart Failure Transplantation Ejection fraction Pulmonary Gas Exchange business.industry Respiration Carbon Dioxide Middle Aged medicine.disease Blood pressure Heart failure Exercise Test Cardiology Physical therapy Exercise intensity Female Surgery Cardiology and Cardiovascular Medicine Ventilatory threshold business |
| Zdroj: | The Journal of Heart and Lung Transplantation. 25:589-595 |
| ISSN: | 1053-2498 |
| DOI: | 10.1016/j.healun.2005.11.448 |
| Popis: | Background Ventilatory efficiency, the relationship between ventilation (VE) and carbon dioxide production (VCO 2 ), predicts mortality in heart failure patients, but its determination has not been standardized. Additionally, it is unclear if the prognostic power of ventilatory efficiency is independent of exercise intensity. Therefore, we investigated the relative prognostic power of different measures of ventilatory efficiency calculated from maximal and sub-maximal exercise in patients with heart failure. Methods and Results Heart failure patients ( n = 355, 72% males, age 51 ± 10 years) had follow-up for at least 5 years from an exercise test. There were 145 events (133 deaths and 12 emergent cardiac transplants). Ventilatory efficiency calculations were not equivalent. Of the different measures of ventilatory efficiency, the VE/VCO 2 slope to peak exercise was the most significant predictor of mortality in a multivariable Cox model, including ejection fraction, systolic blood pressure, peak oxygen consumption (VO 2 ), gender, etiology, and heart rate. A 5 U increment of the VE/VCO 2 slope to peak exercise corresponded to a 9% increase in mortality risk. When tests were grouped by peak exercise intensity, by quartiles of peak respiratory exchange ratio, the VE/VCO 2 slope to peak exercise was always a better predictor than peak VO 2 . Conclusion Peak and sub-maximal measures of ventilatory efficiency were not equivalent, and the VE/VCO 2 slope to peak exercise was the best predictor of mortality in patients with heart failure. Thus, the prognostic power of ventilatory efficiency is enhanced when exercise extends beyond the ventilatory threshold and includes all of the available exercise data. |
| Databáze: | OpenAIRE |
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