Phenotyping Exercise Limitation in Systemic Sclerosis: The Use of Cardiopulmonary Exercise Testing

Abstract

Background: Exercise impairment is a common symptom of systemic sclerosis (SSc), a disorder which is frequently complicated by cardiopulmonary involvement. Objectives: This study's aims were: (a) to define the prevalence and the potential causes of limited exercise capacity and (b) to study potential differences in clinical, radiological and functional characteristics and blood serology among SSc patients with exercise limitation of different etiology. Methods: Prospectively collected data on SSc patients who had conducted full lung function testing, blood serology, thorax high-resolution computed tomography, Doppler echocardiogram and a maximal cardiopulmonary exercise testing (CPET) were retrospectively analyzed. Using a CPET algorithm, patients were characterized as having normal or subnormal exercise capacity (N), respiratory limitation (RL), left ventricular dysfunction (LVD) or pulmonary vasculopathy (PV). Group comparisons were conducted using either one-way ANOVA or the Kruskal-Wallis test. A p value <0.05 was considered significant. Results: The study population consisted of 78 patients (53.7 ± 13.7 years old; 10.3% male). PV was present in 32.1%, LVD in 25.6% and RL in 10.2%, while 32.1% of the patients constituted the N group. The presence of antisclero-70 antibodies, low anaerobic threshold and low peak exercise capacity measures could discriminate LVD from the other groups. Low end-tidal carbon dioxide pressure and its change from rest to anaerobic threshold could discriminate between the PV, LVD and N groups, while respiratory restriction along with ventilatory inefficiency indices could differentiate the RL group from the rest. Conclusions: The combined evaluation of CPET gas exchange patterns with baseline measurements could discriminate the causes of exercise limitation among SSc patients.

Prognostic value of cardiopulmonary exercise testing in patients with systemic sclerosis

“…In a recent study of 226 patients with idiopathic PAH, peakVO 2 , VO 2 @AT, VO 2 /heart rate, p et-CO 2 @rest, p et CO 2 @AT, VE/VCO 2 -slope and VE/VCO 2 @rest were related to survival in a univariate analysis (in a multivariate analysis only peakVO 2 and VE/VCO 2 @rest were retained) [74]. Interestingly, CPET parameters can be sensitive in cases of pulmonary vasculopathy without manifested PH or PAH [10,75,76], because in these cases the integration of different cardiac, muscle and pulmonary pathologies in CPET parameters allows prognostication. Moreover, CPET can differentiate between predominantly cardiac and predominantly pulmonary manifestation, and increase the pre-test probability for PH [77].…”

“…In particular, CPET provides an important insight into exercise physiology, and has shown patients with SSc to have a lower cardiopulmonary exercise capacity, measured as peak oxygen uptake (peakVO 2 ) [8] and as the relationship between ventilation and carbon dioxide output (VE/VCO 2 -slope) [9], compared with control individuals. Recent studies suggest that CPET can be used to determine whether the primary cause of exercise capacity limitation is cardiac or pulmonary in origin [10,11]. Prognosis in SSc has not previously been assessed using CPET.…”

Exercise capacity in borderline mean pulmonary artery pressure: Is it all about peak VO2?

“…Moreover, although pulmonary artery wedge pressure was <15 mm Hg in both groups, it was significantly higher among those with boPAP; these patients also presented with higher right atrial pressure. Literature data indicate that the slope of PETCO 2 , that is the change of PETCO 2 from rest to AT, 7,8 might also be helpful to diagnose between inert left heart disease and inert pulmonary vasculopathy, so comparison of its values between the two groups could have given further discriminative information.…”

Exercise-based evaluations and interventions for pulmonary hypertension with connective tissue disorders

“…Most CTDs, irrespective of the cause, tend to affect the pulmonary system and cause interstitial lung disease. [20,21] In addition, many of them also suffer from co-morbid conditions such as cardiovascular disease (17% and 67% among survivors and deceased respectively) [22] and cardiac anomalies such as LV dysfunction (25.6%) [23], valvular regurgitation (aortic or mitral) (60%) along with changes to the LV structure. [24,25] These cardiovascular conditions in the long run could result in heart failure and further reduce exercise tolerance.…”