Ventilatory efficiency testing as prognostic value in patients with pulmonary hypertension

Abstract

BackgroundIncreased ventilatory response has been shown to have a high prognostic value in patients with chronic heart failure. Our aim was therefore to determine the ventilatory efficiency in pulmonary arterial hypertension and chronic thromboembolic pulmonary hypertension by cardiopulmonary exercise testing (CPET) identifying PH-patients with increased risk for death within 24 months after evaluation.Methods116 patients (age: 64 ± 1 years) with a mean pulmonary arterial pressure of 35 ± 1 mmHg underwent CPET and right heart catheterization. During a follow-up of 24 months, we compared the initial characteristics of survivors (n = 87) with nonsurvivors (n = 29).ResultsSignificant differences (p ≤ 0.005) between survivors and nonsurvivors existed in ventilatory equivalents for oxygen (42.1 ± 2.1 versus 56.9 ± 2.6) and for carbon dioxide (Ve/VCO2) (47.5 ± 2.2 versus 64.4 ± 2.3). Patients with peak oxygen uptake ≤ 10.4 ml/min/kg had a 1.5-fold, Ve/VCO2 ≥ 55 a 7.8-fold, alveolar-arterial oxygen difference ≥ 55 mmHg a 2.9-fold, and with Ve/VCO2 slope ≥ 60 a 5.8-fold increased risk of mortality in the next 24 months.ConclusionsOur results demonstrate that abnormalities in exercise ventilation powerfully predict outcomes in PH. Consideration should be given to add clinical guidelines to reflect the prognostic importance of ventilatory efficiency parameters in addition to peak VO2.

Exertional dyspnoea in pulmonary arterial hypertension

“…This may explain why V′E/V′CO 2 not only reflects the severity of PAH, but is also a powerful predictor of prognosis, as it integrates the function of the cardiac, respiratory and nervous systems [10]. While the V′E/V′CO 2 slope is usually elevated in the range of 35-45 in mild PAH patients [33], a V′E/V′CO 2 slope >60 (or EqCO 2 >54) is typically observed in severe patients, which portends a significantly increased risk of death [43,44]. A low end-tidal carbon dioxide tension (PETCO 2 ) and PaCO 2 are also useful markers of PAH severity during exercise testing, as they reflect inefficient ventilation due to both high dead space and altered chemoreflex sensitivity with a lower PaCO 2 set-point [22,25,34].…”

Ventilatory efficiency in children and adolescents born extremely preterm

“…Whether differences in physical fitness or cardiovascular effects secondary to the differences in lung function contribute to a lower VO 2peak remains unanswered. However, if EP−born participants have exercise induced pulmonary hypertension as indicated in a recent study (Abman et al, 2017), a higher slope of the HR −VO 2 relationship would be expected, and a higher slope of the V E −VCO 2 is a characteristic of pulmonary hypertension (Schwaiblmair et al, 2012). The functional significance is modest only and the alveolar to arterial difference in oxygen pressure appear not to be widened (Duke et al, 2014), indicating that ventilatory capacity is not limiting exercise.…”

The Role of Exercise Testing in the Modern Management of Pulmonary Arterial Hypertension

“…Several CPET variables have been demonstrated to have prognostic value for patients with PAH although some of the studies are limited by small numbers and lack of multivariate analyses [89,90]. Themes emerging from the heterogeneous results are summarised in Table 2.…”