Effects of high- and moderate-intensity exercise on central hemodynamic and oxygen uptake recovery kinetics in CHF-COPD overlap

Haemodynamic compensations for exercise tissue oxygenation in early stages of COPD: an integrated cardiorespiratory assessment study

BACKGROUND

Cardiovascular comorbidities are increasingly being recognised in early stages of chronic obstructive pulmonary disease (COPD) yet complete cardiorespiratory functional assessments of individuals with mild COPD or presenting with COPD risk factors are lacking. This paper reports on the effectiveness of the cardiocirculatory-limb muscles oxygen delivery and utilisation axis in smokers exhibiting no, or mild to moderate degrees of airflow obstruction using standardised cardiopulmonary exercise testing (CPET).

METHODS

Post-bronchodilator spirometry was used to classify participants as 'ever smokers without' (n=88), with 'mild' (n=63) or 'mild-moderate' COPD (n=56). All underwent CPET with continuous concurrent monitoring of oxygen uptake (V'O2) and of bioimpedance cardiac output (Qc) enabling computation of arteriovenous differences (a-vO2). Mean values of Qc and a-vO2 were mapped across set ranges of V'O2 and Qc isolines to allow for meaningful group comparisons, at same metabolic and circulatory requirements.

RESULTS

Peak exercise capacity was significantly reduced in the 'mild-moderate COPD' as compared with the two other groups who showed similar pulmonary function and exercise capacity. Self-reported cardiovascular and skeletal muscle comorbidities were not different between groups, yet disease impact and exercise intolerance scores were three times higher in the 'mild-moderate COPD' compared with the other groups. Mapping of exercise Qc and a-vO2 also showed a leftward shift of values in this group, indicative of a deficit in peripheral O2 extraction even for submaximal exercise demands. Concurrent with lung hyperinflation, a distinctive blunting of exercise stroke volume expansion was also observed in this group.

CONCLUSION

Contrary to the traditional view that cardiovascular complications were the hallmark of advanced disease, this study of early COPD spectrum showed a reduced exercise O2 delivery and utilisation in individuals meeting spirometry criteria for stage II COPD. These findings reinforce the preventive clinical management approach to preserve peripheral muscle circulatory and oxidative capacities.

PREVALENCE AND IMPACT OF COMORBIDITIES IN INDIVIDUALS WITH COPD: A SYSTEMATIC REVIEW

This study aimed to describe the prevalence of comorbidities associated with chronic obstructive pulmonary disease (COPD) and their relation with relevant outcomes. A systematic review based on the PRISMA methodology was performed from January 2020 until July 2021. The MEDLINE, Lilacs, and Scielo databases were searched to identify studies related to COPD and its comorbidities. Observational studies on the prevalence of comorbidities in COPD patients and costs with health estimates, reduced quality of life, and mortality were included. Studies that were restricted to one or more COPD pain assessments and only specific comorbidities such as osteoporosis, bronchitis, and asthma were excluded. The initial search identified 1,409 studies and after applying the inclusion and exclusion criteria, 20 studies were finally selected for analysis (comprising data from 447,459 COPD subjects). The most frequent COPD comorbidities were: hypertension (range, 17%–64.7%), coronary artery disease (19.9%–47.8%), diabetes (10.2%–45%), osteoarthritis (18%–43.8%), psychiatric conditions (12.1%–33%), and asthma (14.7%–32.5%). Several comorbidities had an impact on the frequency and severity of COPD exacerbations, quality of life, and mortality risk, in particular malignancies, coronary artery disease, chronic heart failure, and cardiac arrhythmias. Comorbidities, especially cardiovascular diseases and diabetes, are frequent in COPD patients, and some of them are associated with higher mortality.