Value of Cardiopulmonary Exercise Testing in Prognostic Assessment of Patients with Interstitial Lung Diseases

A Summed Score From Cardiopulmonary Exercise Test Parameters Predicts 1-Year Mortality in Newly Diagnosed Interstitial Lung Disease

BACKGROUND

Cardiopulmonary exercise testing (CPET) is a unique diagnostic tool that assesses the functional capacity of the heart, lungs, and peripheral oxidative system in an integrated manner. However, the clinical utility of CPET for evaluating interstitial lung disease (ILD) remains uncertain. The objective of this study was to determine the predictive value of CPET for mortality in subjects with ILD.

METHODS

We prospectively enrolled subjects with ILD who underwent CPET at a tertiary medical center in Taiwan and followed up their survival status for 12 months. Mortality prediction was based on comparing CPET parameters between subjects who survived and those who died. We further analyzed CPET parameters that showed significant differences using receiver operating characteristic curves to identify their optimal cutoff values.

RESULTS

A total of 106 newly diagnosed subjects with ILD underwent CPET, and the 1-y mortality rate was 7.5%. Six CPET variables were found to be significant predictors of mortality: peak oxygen consumption, oxygen pulse, end-tidal partial pressure of carbon dioxide, heart rate recovery 1 min after CPET, minute ventilation to carbon dioxide output slope, and functional aerobic impairment. We calculated a summed score by adding the number of CPET variables that exceeded their cutoff values. Subjects with a summed score of 6 had a 1-y survival rate of only 25%, whereas subjects with scores of 0-5 had a survival rate of 98%.

CONCLUSIONS

In conclusion, the summed score represents a useful tool for screening patients with ILD who can undergo a CPET to determine their prognosis.

Determinants of cardiorespiratory fitness measured by cardiopulmonary exercise testing in COVID-19 survivors: a systematic review with meta-analysis and meta‑regression

BACKGROUND

The relationship between cardiorespiratory fitness and its possible determinants in post-COVID-19 survivors has not been systematically assessed.

OBJECTIVES

To identify and summarize studies comparing cardiorespiratory fitness measured by cardiopulmonary exercise testing in COVID-19 survivors versus non-COVID-19 controls, as well as to determine the influence of potential moderating factors.

METHODS

We conducted a systematic search of MEDLINE/PubMed, Cochrane Library, EMBASE, Google Scholar, and SciELO since their inceptions until June 2022. Mean differences (MD), standard mean differences (SMD), and 95% confidence intervals (CI) were calculated. Subgroup and meta-regression analyses were used to evaluate potential moderating factors.

RESULTS

48 studies (3372 participants, mean age 42 years, and with a mean testing time of 4 months post-COVID-19) were included, comprising a total of 1823 COVID-19 survivors and 1549 non-COVID-19 controls. After data pooling, VO2 peak (SMD=1.0 95% CI: 0.5, 1.5; 17 studies; N = 1273) was impaired in COVID-19 survivors. In 15 studies that reported VO2 peak values in mL/min/kg, non-COVID-19 controls had higher peak VO2 values than COVID-19 survivors (MD=6.2, 95% CI: 3.5, 8.8; N = 905; I2=84%). In addition, VO2 peak was associated with age, time post-COVID-19, disease severity, presence of dyspnea, and reduced exercise capacity.

CONCLUSION

This systematic review provides evidence that cardiorespiratory fitness may be impaired in COVID-19 survivors, especially for those with severe disease, presence of dyspnea, and reduced exercise capacity. Furthermore, the degree of reduction of VO2 peak is inversely associated with age and time post-COVID.

Metabolic cost of unloading pedalling in different groups of patients with pulmonary hypertension and volunteers

Recently, the parameter internal work (IW) has been introduced as change in oxygen uptake (VO2) between resting and unloading workload in cardiopulmonary exercise testing (CPET). The proportional IW (PIW) was defined as IW divided by VO2 at peak exercise. A second option is to calculate the PIW based on the workload [PIW (Watt)] by considering the aerobic efficiency. The aim of our study was to investigate whether IW and PIW differ between patients with and without pulmonary hypertension and healthy controls. Our study population consisted of 580 patients and 354 healthy controls derived from the Study of Health in Pomerania. The PIW was slightly lower in patients (14.2%) than in healthy controls (14.9%; p = 0.030), but the PIW (Watt) was higher in patients (18.0%) than in the healthy controls (15.9%; p = 0.001). Such a difference was also observed, when considering only the submaximal workload up to the VAT (19.8% in patients and 15.1% in healthy controls; p < 0.001). Since the PIW (Watt) values were higher in patients with pulmonary hypertension, this marker may serve as a useful CPET parameter in clinical practice. In contrast to most of the currently used CPET parameters, the PIW does not require a maximal workload for the patient. Further studies are needed to validate the prognostic significance of the PIW.