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Usefulness of decrease in oxygen uptake efficiency to identify gas exchange abnormality in patients with idiopathic pulmonary arterial hypertension.

Tan X, Yang W, Guo J, Zhang Y, Wu C, Sapkota R, Kushwaha SP, Gong S, Sun X, Liu J - PLoS ONE (2014)

Bottom Line: Decline in oxygen uptake efficiency (OUE), especially during exercise, is found in patients with chronic heart failure.OUEP%pred, better than OUES%pred, correlated significantly with New York Heart Association (NYHA) functional Class (r = -0.724, P<0.005), Total Pulmonary Vascular Resistance (TPVR) (r = -0.694, P<0.005), diffusing capacity for carbon monoxide (DLCO) (r = 0.577, P<0.05), and the lowest ventilation versus CO2 output ratio during exercise (LowestV˙E/V˙CO2) (r = -0.902, P<0.0001).In addition, the coefficient of variation (COV) of OUEP was lower (20.9%) markedly than OUES (34.3%) (P<0.0001).

View Article: PubMed Central - PubMed

Affiliation: Department of Pulmonary Function Test, Shanghai Pulmonary Hospital Affiliated to Tongji University, Shanghai, China; State Key Laboratory of Cardiovascular Disease, Heart-Lung Function Testing Center, Fuwai Hospital, National Center for Cardiovascular Diseases, Chinese Academy of Medical Sciences and Peking Union Medical College, Beijing, China.

ABSTRACT

Background: Decline in oxygen uptake efficiency (OUE), especially during exercise, is found in patients with chronic heart failure. In this study we aimed to test the validity and usefulness of OUE in evaluating gas exchange abnormality of patients with idiopathic pulmonary arterial hypertension (IPAH).

Methods: We retrospectively investigated the cardiopulmonary exercise test (CPET) with gas exchange measurements in 32 patients with confirmed IPAH. All patients also had resting hemodynamic measurements and pulmonary function test (PFT). Sixteen healthy subjects, matched by age, sex, and body size were used as controls, also had CPET and PFT measurements.

Results: In IPAH patients, the magnitude of absolute and percentage of predicted (%pred) oxygen uptake efficiency slope (OUES) and oxygen uptake efficiency plateau (OUEP), as well as several other CPET parameters, were strikingly worse than healthy subjects (P<0.0001). Pattern of changes in OUE in patients is similar to that in controls, In IPAH patients, OUE values at rest, warming up, anaerobic threshold and peak exercise were all significantly lower than in normal (P<0.0001). OUEP%pred, better than OUES%pred, correlated significantly with New York Heart Association (NYHA) functional Class (r = -0.724, P<0.005), Total Pulmonary Vascular Resistance (TPVR) (r = -0.694, P<0.005), diffusing capacity for carbon monoxide (DLCO) (r = 0.577, P<0.05), and the lowest ventilation versus CO2 output ratio during exercise (LowestV˙E/V˙CO2) (r = -0.902, P<0.0001). In addition, the coefficient of variation (COV) of OUEP was lower (20.9%) markedly than OUES (34.3%) (P<0.0001).

Conclusions: In patients with IPAH, OUES and OUEP are both significantly lower than the healthy subjects. OUEP is a better physiological parameter than OUES in evaluating the gas exchange abnormality of patients with IPAH.

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Related in: MedlinePlus

Difference of CPET parameters between IPAH and control groups at different stages of exercise.The group mean±SD Values of IPAH) and control (NORMAL) groups are shown at stages of rest, unloaded cycling, AT, and peak exercise during incremental cycle ergometry tests. Values are. On the left side from top to bottom, they are OUE, V˙E/V˙CO2 and PETCO2.; on the right side from top to bottom they are V˙O2, V˙CO2 and V˙E. Statistically significant differences between groups at the same stage are shown as NS for no significance, * for P<0.05, ** for P<0.005, below value symbol.
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pone-0098889-g003: Difference of CPET parameters between IPAH and control groups at different stages of exercise.The group mean±SD Values of IPAH) and control (NORMAL) groups are shown at stages of rest, unloaded cycling, AT, and peak exercise during incremental cycle ergometry tests. Values are. On the left side from top to bottom, they are OUE, V˙E/V˙CO2 and PETCO2.; on the right side from top to bottom they are V˙O2, V˙CO2 and V˙E. Statistically significant differences between groups at the same stage are shown as NS for no significance, * for P<0.05, ** for P<0.005, below value symbol.

Mentions: The left top portion of Figure 3 shows OUE values for patients and normal subjects at four time periods. OUE values at all time periods were markedly lower in IPAH patients than in normal subjects (P<0.001). In control group, the differences in OUE values at four time periods were significant (P<0.001), and changes between adjacent periods were evident (P<0.001). However in IPAH group, the differences in OUE values at four time periods were also significant (P = 0.023), but the magnitude of OUE changes was much smaller than the control group.


Usefulness of decrease in oxygen uptake efficiency to identify gas exchange abnormality in patients with idiopathic pulmonary arterial hypertension.

Tan X, Yang W, Guo J, Zhang Y, Wu C, Sapkota R, Kushwaha SP, Gong S, Sun X, Liu J - PLoS ONE (2014)

Difference of CPET parameters between IPAH and control groups at different stages of exercise.The group mean±SD Values of IPAH) and control (NORMAL) groups are shown at stages of rest, unloaded cycling, AT, and peak exercise during incremental cycle ergometry tests. Values are. On the left side from top to bottom, they are OUE, V˙E/V˙CO2 and PETCO2.; on the right side from top to bottom they are V˙O2, V˙CO2 and V˙E. Statistically significant differences between groups at the same stage are shown as NS for no significance, * for P<0.05, ** for P<0.005, below value symbol.
© Copyright Policy
Related In: Results  -  Collection

License
Show All Figures
getmorefigures.php?uid=PMC4048265&req=5

pone-0098889-g003: Difference of CPET parameters between IPAH and control groups at different stages of exercise.The group mean±SD Values of IPAH) and control (NORMAL) groups are shown at stages of rest, unloaded cycling, AT, and peak exercise during incremental cycle ergometry tests. Values are. On the left side from top to bottom, they are OUE, V˙E/V˙CO2 and PETCO2.; on the right side from top to bottom they are V˙O2, V˙CO2 and V˙E. Statistically significant differences between groups at the same stage are shown as NS for no significance, * for P<0.05, ** for P<0.005, below value symbol.
Mentions: The left top portion of Figure 3 shows OUE values for patients and normal subjects at four time periods. OUE values at all time periods were markedly lower in IPAH patients than in normal subjects (P<0.001). In control group, the differences in OUE values at four time periods were significant (P<0.001), and changes between adjacent periods were evident (P<0.001). However in IPAH group, the differences in OUE values at four time periods were also significant (P = 0.023), but the magnitude of OUE changes was much smaller than the control group.

Bottom Line: Decline in oxygen uptake efficiency (OUE), especially during exercise, is found in patients with chronic heart failure.OUEP%pred, better than OUES%pred, correlated significantly with New York Heart Association (NYHA) functional Class (r = -0.724, P<0.005), Total Pulmonary Vascular Resistance (TPVR) (r = -0.694, P<0.005), diffusing capacity for carbon monoxide (DLCO) (r = 0.577, P<0.05), and the lowest ventilation versus CO2 output ratio during exercise (LowestV˙E/V˙CO2) (r = -0.902, P<0.0001).In addition, the coefficient of variation (COV) of OUEP was lower (20.9%) markedly than OUES (34.3%) (P<0.0001).

View Article: PubMed Central - PubMed

Affiliation: Department of Pulmonary Function Test, Shanghai Pulmonary Hospital Affiliated to Tongji University, Shanghai, China; State Key Laboratory of Cardiovascular Disease, Heart-Lung Function Testing Center, Fuwai Hospital, National Center for Cardiovascular Diseases, Chinese Academy of Medical Sciences and Peking Union Medical College, Beijing, China.

ABSTRACT

Background: Decline in oxygen uptake efficiency (OUE), especially during exercise, is found in patients with chronic heart failure. In this study we aimed to test the validity and usefulness of OUE in evaluating gas exchange abnormality of patients with idiopathic pulmonary arterial hypertension (IPAH).

Methods: We retrospectively investigated the cardiopulmonary exercise test (CPET) with gas exchange measurements in 32 patients with confirmed IPAH. All patients also had resting hemodynamic measurements and pulmonary function test (PFT). Sixteen healthy subjects, matched by age, sex, and body size were used as controls, also had CPET and PFT measurements.

Results: In IPAH patients, the magnitude of absolute and percentage of predicted (%pred) oxygen uptake efficiency slope (OUES) and oxygen uptake efficiency plateau (OUEP), as well as several other CPET parameters, were strikingly worse than healthy subjects (P<0.0001). Pattern of changes in OUE in patients is similar to that in controls, In IPAH patients, OUE values at rest, warming up, anaerobic threshold and peak exercise were all significantly lower than in normal (P<0.0001). OUEP%pred, better than OUES%pred, correlated significantly with New York Heart Association (NYHA) functional Class (r = -0.724, P<0.005), Total Pulmonary Vascular Resistance (TPVR) (r = -0.694, P<0.005), diffusing capacity for carbon monoxide (DLCO) (r = 0.577, P<0.05), and the lowest ventilation versus CO2 output ratio during exercise (LowestV˙E/V˙CO2) (r = -0.902, P<0.0001). In addition, the coefficient of variation (COV) of OUEP was lower (20.9%) markedly than OUES (34.3%) (P<0.0001).

Conclusions: In patients with IPAH, OUES and OUEP are both significantly lower than the healthy subjects. OUEP is a better physiological parameter than OUES in evaluating the gas exchange abnormality of patients with IPAH.

Show MeSH
Related in: MedlinePlus