Biomedical subjects

Christophe Van Laethem

Publications and source records attributed to Christophe Van Laethem.

3 recordsLinked to original sources

PubMed2006

Prospective evaluation of the oxygen uptake efficiency slope as a submaximal predictor of peak oxygen uptake in aged patients with ischemic heart disease.

BACKGROUND: The purpose of this study was to evaluate the oxygen uptake efficiency slope (OUES) as a predictor of peak oxygen consumption (VO2) in aged patients with coronary artery disease (CAD) and to compare its predictive value to that of ventilatory anaerobic threshold (VAT). METHODS: A total of 160 aged (>60 years) patients with stable CAD performed a maximal cardiopulmonary exercise test. The equations were computed by using data of 85 randomly selected patients and were validated in the remaining 75 patients. Bland-Altman (BA) analysis was used to assess the agreement between measured and predicted peak VO2. RESULTS: In the first 85 patients, peak VO2 correlated best with VAT and OUES per kilogram (P < .001). The linear regression to predict peak VO2 for OUES per kilogram was peak VO2 = 4.591 + 0.64 x OUES/kg (SEE = 2.61 mL kg(-1) min(-1)). The BA 95% limits of agreement were -29% and +30% of the predicted value. For VAT, the linear regression to predict peak VO2 was peak VO2 = 2.995 + 1.251 x VAT (SEE = 2.26 mL kg(-1) min(-1)). The BA 95% limits of agreement were -23% and +33% of the predicted value. Cross-tabulation analysis in 3 subgroups with different exercise capacities showed significant relationship between predicted and measured peak VO2 (all P < .001). OUES per kilogram showed the best measure of agreement with measured peak VO2, resulting in high sensitivity and specificity scores. CONCLUSION: OUES is not able to acceptably predict peak VO2 in aged patients with CAD but is at least as performant as VAT in categorizing patients into subgroups with different exercise capacities. Therefore, the objectively measurable OUES is the preferred submaximal predictor of functional capacity in the assessment of aged patients with CAD.

Acridines↗

PubMed2006

VE/VCO2 slope and oxygen uptake efficiency slope in patients with coronary artery disease and intermediate peakVO2.

BACKGROUND: Peak exercise oxygen uptake (peakVO2) is a widely used prognosticator. Novel spirometric parameters, less affected by submaximal performance, such as the rate of increase of minute ventilation per unit decrease of carbon dioxide production (VE/VCO2 slope) and the oxygen uptake efficiency slope (OUES) have recently been introduced. AIM: To evaluate the discriminative value of OUES, as compared to VE/VCO2 slope in patients with coronary artery disease (CAD) and intermediate peakVO2 values. METHODS AND RESULTS: Bicycle spiroergometry was applied in 214 patients with CAD (age 67+/-8 years, 85% men). OUES was strongly related to peakVO2 (r=0.79). New York Heart Association (NYHA) class, 6-min walking distance, N-terminal pro-brain natriuretic peptide (NT-proBNP), inflammatory markers, left ventricular (LV) volumes and ejection fraction were evaluated. NT-proBNP levels predicted independently VE/VCO2-slope and OUES. Patients with intermediate peakVO2 (12-18 ml/kg per min) and increased VE/VCO2-slope (> or = 35) had higher NYHA class, lower walking distance, higher NT-proBNP levels and higher LV volumes as compared to patients with a similar peakVO2 but lower VE/VCO2-slope. Similar findings were found for patients with intermediate peakVO2 and high OUES/kg (median value>15.3). CONCLUSION: In CAD patients, OUES was strongly correlated with peakVO2. Both VE/VCO2 slope and OUES were independently associated with NT-proBNP levels. Both VE/VCO2 slope and OUES/kg were able to identify a subgroup of patients with an intermediate peakVO2 that was characterized by advanced remodelling and a higher degree of neurohumoral activation.

Aged↗

PubMed2005

Oxygen uptake efficiency slope, a new submaximal parameter in evaluating exercise capacity in chronic heart failure patients.

BACKGROUND: The oxygen uptake efficiency slope (OUES) is a new submaximal parameter which objectively predicts the maximal exercise capacity in children and healthy subjects. However, the usefulness of OUES in adult patients with and without advanced heart failure remains undetermined. The present study investigates the stability and the usefulness of OUES in adult cardiac patients with and without heart failure. METHODS: Forty-five patients with advanced heart failure (group A) and 35 patients with ischemic heart disease but normal left ventricular ejection fraction (group B) performed a maximal exercise test. PeakVO2 and percentage of predicted peakVO2 were markers of maximal exercise capacity, whereas OUES, ventilatory anaerobic threshold (VAT), and slope VE/VCO2 were calculated as parameters of submaximal exercise. RESULTS: Group A patients had lower peakVO2 (P < .001), lower percentage of predicted peakVO2 (P = .001), lower VAT (P < .05), steeper slope VE/VCO2 (P < .001), and lower OUES (P < .02). Within group A, significant differences were found for VAT, slope VE/VCO2, and OUES (all P < .01) between patients with peakVO2 above and below 14 mL O2/kg/min. Of all the submaximal parameters, VAT correlated best with peakVO2 (r =.814, P < .01) followed by OUES/kg (r = .781, P < .01), and slope VE/VCO2 (r = -.492, P < .001). However, VAT could not be determined in 18 (23%) patients. CONCLUSIONS: OUES remains stable over the entire exercise duration and is significantly correlated with peakVO2 in adult cardiac patients with and without impaired LVEF. Therefore, OUES could be helpful to assess exercise performance in advanced heart failure patients unable to perform a maximal exercise test. Further studies are needed to confirm our hypothesis.

Adult↗