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V E / V CO 2 slope is associated with abnormal resting haemodynamics and is a predictor of long‐term survival in chronic heart failure
Author(s) -
Nanas Serafim N.,
Nanas John N.,
Sakellariou Dimitrios Ch.,
Dimopoulos Stavros K.,
Drakos Stavros G.,
Kapsimalakou Smaragdo G.,
Mpatziou Christina A.,
Papazachou Ourania G.,
Dalianis Anargyros S.,
AnastasiouNana Maria I.,
Roussos Charis
Publication year - 2006
Publication title -
european journal of heart failure
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 5.149
H-Index - 133
eISSN - 1879-0844
pISSN - 1388-9842
DOI - 10.1016/j.ejheart.2005.10.003
Subject(s) - medicine , heart failure , cardiology , hemodynamics , pulmonary wedge pressure , vo2 max , ejection fraction , heart rate , blood pressure
Background: Patients with chronic heart failure (CHF) present with exercise‐induced hyperpnea, but its pathophysiological mechanism has not been thoroughly investigated. We aimed to determine the relationship between exercise‐induced hyperpnea, resting haemodynamic measurements and the validity of ventilatory response ( V E / V CO 2 slope) as a mortality predictor in CHF patients. Methods: Ninety‐eight CHF patients (90M/8F) underwent a symptom‐limited treadmill cardiopulmonary exercise test (CPET). Right heart catheterization and radionuclide ventriculography were performed within 72 h of CPET. Results: Twenty‐seven patients died from cardiac causes during 20±6 months follow‐up. Non‐survivors had a lower peak oxygen consumption ( V O 2p ), (16.5±4.9 vs. 20.2±6.1, ml/kg/min, p =0.003), a steeper V E / V CO 2 slope (34.8±8.3 vs. 28.9±4.8, p <0.001) and a higher pulmonary capillary wedge pressure (PCWP) (19.5±8.6 vs. 11.7±6.5 mm Hg, p =0.008) than survivors. By multivariate survival analysis, the V E / V CO 2 slope as a continuous variable was an independent prognostic factor ( χ 2 : 8.5, relative risk: 1.1, 95% CI: 1.03–1.18, p =0.004). Overall mortality was 52% in patients with V E / V CO 2 slope ≥34 and 18% in those with V E / V CO 2 slope <34 (log rank: 18.5, p <0.001). In a subgroup of patients ( V O 2 p: 10–18 ml/kg/min), V E / V CO 2 slope was a significant predictor of mortality (relative risk: 6.2, 95% CI: 1.7–22.2, p =0.002). Patients with high V E / V CO 2 slope had higher resting PCWP (19.9±9.1 vs. 11.3±5.7 mmHg, p <0.001) and V E / V CO 2 slope correlated significantly with PCWP ( r : 0.57, p <0.001). Conclusions: The V E / V CO 2 slope, as an index of ventilatory response to exercise, improves the risk stratification of CHF patients. Interstitial pulmonary oedema may be a pathophysiological mechanism of inefficient ventilation during exercise in these patients.