TY - JOUR
T1 - Normalization for peak oxygen uptake increases the prognostic power of the ventilatory response to exercise in patients with chronic heart failure
AU - Guazzi, Marco
AU - De Vita, Stefano
AU - Cardano, Paola
AU - Barlera, Simona
AU - Guazzi, Maurizio D.
PY - 2003/9/1
Y1 - 2003/9/1
N2 - Background: Peak exercise oxygen uptake (peak VO
2) and ventilation to CO
2 production (VE/VCO
2) slope are established prognostic indicators in patients with chronic heart failure (CHF). A high VE/VCO
2 slope, however, does not take into account the level of physical performance as expressed by peak VO
2. We hypothesized that the prognostic value of a high VE/VCO
2 slope may be improved by normalization for peak VO
2 (VE/VCO
2/VO
2). Methods: One hundred patients with CHF underwent pulmonary function tests at rest (spirometry and lung diffusion capacity) and maximal cardiopulmonary exercise testing. The prognostic value of VE/VCO
2 slope, peak VO
2 and VE/VCO
2/VO
2 was probed prospectively. Results: Twenty-one patients died from cardiac reasons during a mean follow-up of 26 ± 19 months. Nonsurvivors, compared to survivors, showed a lower peak VO
2 (13.6 ± 4.0 vs 17.5 ± 4.1 mL · min
-1 · kg
-1, P <.01) and a steeper VE/VCO
2 slope (43 ± 11 vs 31.6 ± 5.0, P <.01). Nonetheless, in patients whose VE/VCO
2 slope exceeded 34 (upper normal limit), there was no correlation with peak VO
2 (r = -35, P = not significant). Interestingly 35% of them showed a normal exercise performance (peak VO
2 ≥18 mL · min
-1 · kg
-1). At multivariate analysis, the VE/VCO
2 slope showed a prognostic power stronger than that of peak VO
2; however, the VE/VCO
2/VO
2 index retained a prognostic power greater than that of both VE/VCO
2 slope and peak VO
2. A VE/VCO
2/VO
2 ≥2.4 signaled cases at higher risk. Conclusions: Discrepancies between VE/VCO
2 slope and peak VO
2 may generate uncertainty. Normalization of the former by the latter improves outcome prediction and may be considered a simple and effective way for maximizing the clinical applicability of these 2 indicators.
AB - Background: Peak exercise oxygen uptake (peak VO
2) and ventilation to CO
2 production (VE/VCO
2) slope are established prognostic indicators in patients with chronic heart failure (CHF). A high VE/VCO
2 slope, however, does not take into account the level of physical performance as expressed by peak VO
2. We hypothesized that the prognostic value of a high VE/VCO
2 slope may be improved by normalization for peak VO
2 (VE/VCO
2/VO
2). Methods: One hundred patients with CHF underwent pulmonary function tests at rest (spirometry and lung diffusion capacity) and maximal cardiopulmonary exercise testing. The prognostic value of VE/VCO
2 slope, peak VO
2 and VE/VCO
2/VO
2 was probed prospectively. Results: Twenty-one patients died from cardiac reasons during a mean follow-up of 26 ± 19 months. Nonsurvivors, compared to survivors, showed a lower peak VO
2 (13.6 ± 4.0 vs 17.5 ± 4.1 mL · min
-1 · kg
-1, P <.01) and a steeper VE/VCO
2 slope (43 ± 11 vs 31.6 ± 5.0, P <.01). Nonetheless, in patients whose VE/VCO
2 slope exceeded 34 (upper normal limit), there was no correlation with peak VO
2 (r = -35, P = not significant). Interestingly 35% of them showed a normal exercise performance (peak VO
2 ≥18 mL · min
-1 · kg
-1). At multivariate analysis, the VE/VCO
2 slope showed a prognostic power stronger than that of peak VO
2; however, the VE/VCO
2/VO
2 index retained a prognostic power greater than that of both VE/VCO
2 slope and peak VO
2. A VE/VCO
2/VO
2 ≥2.4 signaled cases at higher risk. Conclusions: Discrepancies between VE/VCO
2 slope and peak VO
2 may generate uncertainty. Normalization of the former by the latter improves outcome prediction and may be considered a simple and effective way for maximizing the clinical applicability of these 2 indicators.
UR - http://www.scopus.com/inward/record.url?scp=0042833221&partnerID=8YFLogxK
UR - http://www.scopus.com/inward/citedby.url?scp=0042833221&partnerID=8YFLogxK
U2 - 10.1016/S0002-8703(03)00321-1
DO - 10.1016/S0002-8703(03)00321-1
M3 - Article
C2 - 12947376
AN - SCOPUS:0042833221
VL - 146
SP - 542
EP - 548
JO - American Heart Journal
JF - American Heart Journal
SN - 0002-8703
IS - 3
ER -