Dynamic hyperinflation is associated with a poor cardiovascular response to exercise in COPD patients

Abstract

BackgroundPulmonary hyperinflation has the potential for significant adverse effects on cardiovascular function in COPD. The aim of this study was to investigate the relationship between dynamic hyperinflation and cardiovascular response to maximal exercise in COPD patients.MethodsWe studied 48 patients (16F; age 68 yrs ± 8; BMI 26 ± 4) with COPD. All patients performed spirometry, plethysmography, lung diffusion capacity for carbon monoxide (TLco) measurement, and symptom-limited cardiopulmonary exercise test (CPET). The end-expiratory lung volume (EELV) was evaluated during the CPET. Cardiovascular response was assessed by change during exercise in oxygen pulse (ΔO2Pulse) and double product, i.e. the product of systolic blood pressure and heart rate (DP reserve), and by the oxygen uptake efficiency slope (OUES), i.e. the relation between oxygen uptake and ventilation.ResultsPatients with a peak exercise EELV (%TLC) ≥ 75% had a significantly lower resting FEV1/VC, FEF50/FIF50 ratio and IC/TLC ratio, when compared to patients with a peak exercise EELV (%TLC) < 75%. Dynamic hyperinflation was strictly associated to a poor cardiovascular response to exercise: EELV (%TLC) showed a negative correlation with ΔO2Pulse (r = - 0.476, p = 0.001), OUES (r = - 0.452, p = 0.001) and DP reserve (r = - 0.425, p = 0.004). Furthermore, according to the ROC curve method, ΔO2Pulse and DP reserve cut-off points which maximized sensitivity and specificity, with respect to a EELV (% TLC) value ≥ 75% as a threshold value, were ≤ 5.5 mL/bpm (0.640 sensitivity and 0.696 specificity) and ≤ 10,000 Hg · bpm (0.720 sensitivity and 0.783 specificity), respectively.ConclusionThe present study shows that COPD patients with dynamic hyperinflation have a poor cardiovascular response to exercise. This finding supports the view that in COPD patients, dynamic hyperinflation may affect exercise performance not only by affecting ventilation, but also cardiac function.

Teste cardiopulmonar de exercício na DPOC: indo além do consumo máximo de oxigênio

“…In addition, peripheral muscle strength and respiratory muscle strength were found to be relatively preserved. These findings are in contrast with those reported by Terziyski et al (9) and, in particular, with those reported by Tzani et al (10) in patients with more advanced disease, in whom the OUES was actually reduced.…”

“…A joint analysis of the results of the study by Müller et al (5) and those reported in the abovementioned studies (9,10) allows us to conclude that evaluating the OUES seems to be more relevant in patients with COPD that is more severe, in whom airflow limitation and cardiovascular limitation are more common, and in those with mild COPD and underlying cardiovascular disease. In that same line of thought, it is expected that reduced OUES, together with other CPET variables, can assist in the prognostic evaluation of this population, especially if we take into consideration the central role that cardiovascular comorbidities play in COPD mortality.…”

Fat-Free Mass Depletion Is Associated With Poor Exercise Capacity Irrespective of Dynamic Hyperinflation in COPD Patients

“…A poor cardiovascular response to exercise was related to dynamic hyperinflation on exertion in patients with severe COPD, 5 and this finding has been recently confirmed and extended by our group in patients with a wide range of air-flow obstruction. 6 In the present series, the depleted patients, compared with nondepleted patients, significantly differed in cardiovascular response to exercise, for a given level of hyperinflation at rest and on exertion, indicating that a low FFM may independently affect cardiovascular function. Indeed, both resting and peak O 2 pulse values were significantly lower in depleted patients compared with nondepleted patients, whereas peak O 2 pulse strongly related to FFM in the whole population.…”

“…The patients with an IC/TLC at the peak of exercise of Յ 0.25 may be defined as "heavy hyperinflators." 5,6 On the basis of the age of our population sample, a value of 10 mL/kg/min may be considered as a threshold value of normality for the peak O 2 pulse. 27 A P value of Ͻ .05 was taken as significant.…”

“…4 Furthermore, the ventilatory constraints occurring during exercise have the potential for significant negative effects on cardiovascular function. 5,6 Additionally, a fat-free mass (FFM) depletion commonly occurs in COPD patients, resulting from several factors, such as systemic inflammatory mediators, disuse atrophy, poor nutrition, and oral corticosteroid medication. 7 Importantly, the reduction in FFM may also contribute to impairment of exercise capacity in these patients.…”