Pulmonary vascular response patterns during exercise in interstitial lung disease

Abstract

When overt pulmonary hypertension arises in interstitial lung disease (ILD), it contributes to exercise intolerance. We sought to determine the functional significance of abnormal pulmonary arterial pressure (PAP) responses to exercise in ILD.27 ILD patients and 11 age-matched controls underwent invasive cardiopulmonary exercise testing (iCPET). Mean PAP (mPAP) was indexed to cardiac output (Q´T) during exercise, with a mPAP-Q´T slope ⩾3 mmHg·min·L −1 defined as an abnormal pulmonary vascular response. All control subjects had mPAP-Q´T slopes <3 mmHg·min·L −1 (mean±SEM 1.5±0.1 mmHg·min·L −1 ). 15 ILD patients had mPAP-Q´T slopes ⩾3 mmHg·min·L −1 (4.1±0.2 mmHg·min·L) and were labelled as having ILD plus pulmonary vascular dysfunction (PVD). Subjects without pulmonary hypertension and with mPAP-Q´T slopes <3 mmHg·min·L −1 (1.9±0. 2 mmHg·min·L −1) were labelled as ILD minus PVD (n=12). ILD+PVD and ILD−PVD patients did not differ in terms of age, sex, body mass index, pulmonary function testing or degree of exercise oxygen desaturation. Peak oxygen consumption was lower in ILD+PVD than in ILD−PVD (13.0±0.9 versus 17±1.1 mL·kg , p=0.003). ILD+PVD patients had increased dead space volume (VD)/tidal volume (VT) and minute ventilation/carbon dioxide production at the anaerobic threshold.In ILD, mPAP-Q´T slope ⩾3 mmHg·min·L −1 is associated with lower peak oxygen consumption, increased VD/VT and inefficient ventilation. While noninvasive parameters were unable to predict those with abnormal pulmonary vascular responses to exercise, iCPET-derived mPAP-Q´T slope may aid in identifying physiologically significant, early pulmonary vascular disease in ILD.@ERSpublications PAP responses to exercise may help to refine resting phenotypes related to pulmonary vascular dysfunction in ILD http://ow.ly/M0nMa

Exercise-induced pulmonary hypertension: at last!

“…These results confirm previous reports that a steep mPAP−CO relationship, starting at the upper limit of normal, is associated with a decreased exercise capacity [15,18,[20][21][22][23]. This is presumably related to an afterload limitation of right ventricular flow output, but may require confirmation with exercise measurements of function, cardiac output and oxygen extraction.…”

“…In the second study, DEGANI-COSTA et al [20] report on exercise haemodynamics in 27 patients with interstitial lung disease (ILD) and normal or near-normal mPAP at rest and in 11 matched controls. All control subjects had a mPAP−CO slope <3 mmHg·min·L −1 which confirms, once again, current views on the limits of normal of the pulmonary circulation [9,10].…”

Pulmonary vascular and cardiac impairment in interstitial lung disease

“…Recently, DEGANI-COSTA et al [61] reported on exercise haemodynamics in 27 patients with ILD and normal or near-normal mPAP at rest and 11 matched controls. 15 patients had an abnormally steep mPAP−cardiac output slope ⩾3 mmHg·min·L , indicating an abnormal pulmonary vascular response to exercise.…”

Exertional dyspnoea in interstitial lung diseases: the clinical utility of cardiopulmonary exercise testing

“…In the retrospective study of ARMSTRONG et al [71], ILD patients with pulmonary hypertension demonstrated significantly lower end-tidal carbon dioxide tension PETCO 2 and mixed expired carbon dioxide pressure (PECO 2 ) during exercise with a distinctive activity pattern for PECO 2 /PETCO 2 . DEGANI-COSTA et al [72] aimed to determine the functional significance of abnormal pulmonary arterial pressure (PAP) responses to exercise in 27 ILD patients and 11 age-matched controls using invasive cardiopulmonary exercise testing. Mean (m)PAP was indexed to cardiac output (Q′T) during exercise, with a mPAP-Q′T slope ⩾3 mmHg·min·L −1 defined as an abnormal pulmonary vascular response.…”