Low peak Paco2 (<35 mmHg) during exercise was the strongest independent predictor of cardiac death in stable heart failure patients (HR 4.65; 95% CI 1.695-12.751; P=0.003).
Cohort (n=128)
Does peak arterial CO2 partial pressure (Paco2) during exercise predict cardiac mortality in stable chronic heart failure patients?
Low peak arterial CO2 partial pressure (<35 mmHg) during exercise is a strong independent predictor of cardiac mortality in patients with stable chronic heart failure, primarily accounting for the prognostic power of the Ve/Vco2 slope.
Effect estimate: HR 4.65 (95% CI 1.695-12.751)
p-value: p=0.003
AIMS: In chronic heart failure (CHF) patients, the ventilation (Ve) needed to eliminate metabolically produced CO(2) during exercise (i.e. the Ve/Vco(2) slope) is a strong prognosticator. Ve/Vco(2) slope determinants are the dead space-tidal volume (Vd/Vt) ratio and the arterial CO(2) partial pressure (Paco(2)). We aimed at defining the respective prognostic role of these two variables. METHODS AND RESULTS: One hundred and twenty-eight stable CHF patients (average left ventricular ejection fraction 34+/-10%) underwent cardiopulmonary exercise testing and blood gas analysis. The prognostic relevance of the Ve/Vco(2) slope, Vd/Vt, and Paco(2) at peak exercise was evaluated by the Kaplan-Meier approach with log-rank testing and by multivariate Cox regression analysis. During a mean period of 31.3+/-20 months, 24 patients died from cardiac causes. In univariate analysis, predictors of death included the use of anti-aldosterone drugs, low peak Vo(2), peak Ve/Vo(2), peak Paco(2) and high Ve/Vco(2) slope, and peak Vd/Vt. Multivariate analysis identified a low peak Paco(2) (<35 mmHg) as the strongest independent prognostic indicator hazard ratio 4.65, 95% confidence interval (CI) (1.695-12.751), P=0.003 that primarily accounts for the Ve/Vco(2) slope prognostic power. CONCLUSION: These findings imply that regulatory mechanisms involved in the tight control of ventilatory command and blood gas tension, rather than lung function abnormalities, play a critical pathophysiological role in the exercise ventilation inefficiency of CHF patients.
Guazzi et al. (Tue,) conducted a cohort in Chronic heart failure (n=128). Low peak Paco2 (<35 mmHg) was evaluated on Cardiac death (HR 4.65, 95% CI 1.695-12.751, p=0.003). Low peak Paco2 (<35 mmHg) during exercise was the strongest independent predictor of cardiac death in stable heart failure patients (HR 4.65; 95% CI 1.695-12.751; P=0.003).
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