Oxygen Uptake Efficiency Slope in Coronary Artery Disease: Clinical Use and Response to Training

Abstract

The Oxygen Uptake Efficiency Slope (OUES), a new parameter derived from respiratory gas analysis, has been suggested as a submaximal index of cardiopulmonary functional reserve. We evaluated the clinical application and the effect of physical training on the OUES in patients with coronary artery disease (CAD). Maximal cycle-ergometer testing with respiratory gas analysis (breath-by-breath) was performed in 590 patients with CAD and again after three months of physical training in 425 patients. OUES was determined from the linear relation of oxygen uptake (V.O (2)) vs. the logarithm of pulmonary ventilation (V (E)) during exercise, i.e. V.O (2) = a log (10) V (E) + b, where a is the OUES. The ventilatory anaerobic threshold (VAT) and the slope of the relation of V (E) nu carbon dioxide production (V.CO (2)) (V (E)-V.CO (2) slope) were also determined. Correlation coefficients of the relation from which OUES was derived in individuals averaged 0.975 +/- 0.024 (mean +/- SD) when calculated from data up to a respiratory gas exchange ratio of 1.0. Submaximal OUES was marginally lower (5.4 +/- 7.9 %, p < 0.05) than the OUES calculated from 100 % of respiratory exercise data. Of all submaximal parameters, submaximal OUES (r = 0.837, p < 0.001) and VAT (r = 0.860, p < 0.001) correlated best with peak V.O (2), followed by V (E)-V.CO (2) slope (r = - 0.469, p < 0.001). OUES was lower in patients who underwent coronary artery bypass grafting as compared with patients after coronary angioplasty (p < 0.05). Peak V.O (2) and OUES increased significantly (p < 0.001) after training with 24 +/- 19.2 % and 20.9 +/- 19.3 %, respectively. Changes in peak V.O (2) correlated better with changes in OUES and in VAT (r = 0.61 and r = 0.55, p < 0.001, respectively) than with changes in V (E)-V.CO (2) slope (r = - 0.171, p < 0.001). The submaximal OUES is clinically useful for the quantification of exercise performance and is sensitive to physical training in patients with CAD.

Comparison of High Intensity Interval to Moderate Intensity Continuous Aerobic Exercise on Ventilatory Markers in Coronary Heart Disease Patients: A Randomized Controlled Study

“…No differences were found after training in slope of VE/VCO 2 and OUES in the present study. This result was unsuited with previous research in patients with HF [23,24]. Several interpretations explained the non significant change in slope of VE/VCO 2 and OUES in the present study results.…”

“…Also, all of the patients in the study were stable at intervention time with ejection fraction means of nearly 63%. VE/VCO 2 slope and OUES means at the beginning of the study were approximately (27.5 and 1.8) for all patients, which were under the common measures for high risk (typically more than 34 for slope of VE/VCO 2 and less than 1.4 for OUES) and less than measures taken by researches providing an enhancements of the variables in consequences of exercise training [24][25][26]. So, it is probable to believe that the patients in this study had low rank to demonstrate efficient ventilatory gains than subjects with a severe level comprised in earlier studies.…”

Prognostic value of the post-training oxygen uptake efficiency slope in patients with coronary artery disease

“…One of those parameters is the oxygen uptake efficiency slope (OUES), which is a marker of cardiorespiratory functional reserve that represents the relationship between minute ventilation (VE) and oxygen uptake (VO 2 ) during graded exercise. [8][9][10] The OUES is an established measure of exercise capacity in patients with cardiac diseases. 8,[11][12][13][14] Furthermore, it seems to be the preferred alternative measure for peak VO 2 in case of submaximal exercise testing, since it correlates highly with peak VO 2 and it has high test-retest reliability.…”

Oxygen Uptake Efficiency Plateau Best Predicts Early Death in Heart Failure

“…[1][2][3] We postulated that management of such patients could be improved by adding more sensitive predictors, further refi ning well-known predictors, or by combining predictors. Currently, in such patients, gas exchange measurements during incremental cardiopulmonary exercise testing (CPET) such as peak oxygen uptake (peak o 2 ) at standard conditions of 0ºC, 760 mm Hg, dry (STPD); anaerobic threshold (AT); peak oxygen pulse; lowest ratio of minute ventilation ( e) at body temperature, ambient atmospheric pressure, saturated with water vapor to minute CO 2 output ( co 2 ) STPD; e -vs-co 2 slope; oscillatory breathing (OB) pattern [3][4][5][6][7][8][9][10] ; and the slope of o 2 to log e (oxygen uptake effi ciency slope [OUES]) [11][12][13][14][15][16][17][18][19][20][21] have been found to be useful in predicting mortality and morbidity and guiding therapy. [3][4][5][6][7][8][9][10] However, the full exercise response pattern of oxygen uptake effi ciency (OUE) ( o 2 / e , mL/L) and specifi cally the measurement of its highest average plateau (OUEP) (mL/L) have not been evaluated.…”