Structural analysis of retinal blood vessels in patients with COPD during a pulmonary rehabilitation program

Vascular Endothelial Damage in COPD: Where Are We Now, Where Will We Go?

BACKGROUND

Chronic obstructive pulmonary disease (COPD) has higher rates among the general population, so early identification and prevention is the goal. The mechanisms of COPD development have not been completely established, although it has been demonstrated that endothelial dysfunction plays an important role. However, to date, the measurement of endothelial dysfunction is still invasive or not fully established. Nailfold video capillaroscopy (NVC) is a safe, non-invasive diagnostic tool that can be used to easily evaluate the microcirculation and can show any possible endothelial dysfunctions early on. The aim of this review is to evaluate if nailfold microcirculation abnormalities can reflect altered pulmonary vasculature and can predict the risk of cardiovascular comorbidities in COPD patients.

METHODS

A systematic literature search concerning COPD was performed in electronic databases (PUBMED, UpToDate, Google Scholar, ResearchGate), supplemented with manual research. We searched in these databases for articles published until March 2024. The following search words were searched in the databases in all possible combinations: chronic obstructive pulmonary disease (COPD), endothelial damage, vascular impairment, functional evaluation, capillaroscopy, video capillaroscopy, nailfold video capillaroscopy. Only manuscripts written in English were considered for this review. Papers were included only if they were able to define a relationship between COPD and endothelium dysfunction.

RESULTS

The search selected 10 articles, and among these, only three previous reviews were available. Retinal vessel imaging, flow-mediated dilation (FMD), and skin autofluorescence (AF) are reported as the most valuable methods for assessing endothelial dysfunction in COPD patients.

CONCLUSIONS

It has been assumed that decreased nitric oxide (NO) levels leads to microvascular damage in COPD patients. This finding allows us to assume NVC's potential effectiveness in COPD patients. However, this potential link is based on assumption; further investigations are needed to confirm this hypothesis.

Automated Retinal Vessel Analysis Based on Fundus Photographs as a Predictor for Non-Ophthalmic Diseases-Evolution and Perspectives

The study of retinal vessels in relation to cardiovascular risk has a long history. The advent of a dedicated tool based on digital imaging, i.e., the retinal vessel analyzer, and also other software such as Integrative Vessel Analysis (IVAN), Singapore I Vessel Assessment (SIVA), and Vascular Assessment and Measurement Platform for Images of the Retina (VAMPIRE), has led to the accumulation of a formidable body of evidence regarding the prognostic value of retinal vessel analysis (RVA) for cardiovascular and cerebrovascular disease (including arterial hypertension in children). There is also the potential to monitor the response of retinal vessels to therapies such as physical activity or bariatric surgery. The dynamic vessel analyzer (DVA) remains a unique way of studying neurovascular coupling, helping to understand the pathogenesis of cerebrovascular and neurodegenerative conditions and also being complementary to techniques that measure macrovascular dysfunction. Beyond cardiovascular disease, retinal vessel analysis has shown associations with and prognostic value for neurological conditions, inflammation, kidney function, and respiratory disease. Artificial intelligence (AI) (represented by algorithms such as QUantitative Analysis of Retinal vessel Topology and siZe (QUARTZ), SIVA-DLS (SIVA-deep learning system), and many others) seems efficient in extracting information from fundus photographs, providing prognoses of various general conditions with unprecedented predictive value. The future challenges will be integrating RVA and other qualitative and quantitative risk factors in a unique, comprehensive prediction tool, certainly powered by AI, while building the much-needed acceptance for such an approach inside the medical community and reducing the "black box" effect, possibly by means of saliency maps.

Optical coherence tomography angiography as a surrogate marker for end-organ resuscitation in sepsis: A review

Sepsis is a severe illness which results in alterations in the end organ microvascular haemodynamics and is associated with a high risk of mortality. There is currently no real-time method of monitoring microcirculatory perfusion during sepsis. Retinal microcirculation is closely linked to cerebral perfusion and may reflect systemic vascular alterations. Retinal perfusion can be assessed using the non-invasive imaging technique of optical coherence tomography angiography (OCTA). This narrative review aims to discuss the utility of using retinal imaging and OCTA in systemic illness and sepsis. OCTA can be used as a functional, non-invasive and real-time biomarker along with other haemodynamic parameters for assessing and managing patients with sepsis.

Analysis of retinal blood vessel diameters in patients with COPD undergoing a pulmonary rehabilitation program

BACKGROUND

Regular exercise positively affects cardiovascular physiology, translating into the adequate capacity of microvascular blood vessels to dilate in response to acute bouts of exercise. However, this remains unstudied in patients with chronic obstructive pulmonary disease (COPD), who often suffer from cardiovascular comorbidity. Therefore, we studied acute changes in retinal blood vessel diameters in response to high-intensity exercise in patients with COPD. The effect of an exercise-based 8-week pulmonary rehabilitation (PR) program was evaluated. We consider changes in these retinal metrics as an indicator of microvascular reactivity.

METHODS

Demographics and clinical characteristics of 41 patients were collected at the start and end of the PR program. Patients performed a high-intensity exercise test on a cycle ergometer at the start and end of the PR program, during which we collected retinal images. Fundus images were taken immediately before and 0, 5, 10, 15, and 30 min after the ergometer test. Widths of retinal blood vessels, represented as Central Retinal Arteriolar and Venular Equivalents (CRAE and CRVE), were calculated.

RESULTS

Thirty patients with COPD completed the study protocol (57% males; mean age: 64 ± 7 years; mean FEV₁: 45 ± 17%pred). We did not observe a change in retinal vessel widths following the ergometer test at the start of the PR program. This null result remained at the end of the 8-week PR program. Our observations did not alter when considering responders and non-responders to PR.

CONCLUSION

Retinal blood vessel diameters of patients with COPD did not change following an exercise test on an ergometer. The exercise-based PR program of eight weeks did not counteract the blunted retinal microvascular response.