Lasting Microvascular Damage in Long COVID Patients: A Sublingual Microcirculation Study
A recent study called “Persistent capillary rarefication in long COVID syndrome”, published in the journal ‘Angiogenesis’, provides crucial insights into the persistent microvascular changes in Long COVID patients. This study’s findings highlight the long-term impact of COVID-19 on small blood vessels, even 18 months after infection.
Here’s a summary of its key points:
- Study Design and Methods: The prospective observational study involved 58 participants, including 27 Long COVID patients with symptoms persisting for more than 12 weeks post-recovery. Fifteen healthy volunteers and 16 critically ill COVID-19 patients served as controls. The participants underwent sublingual videomicroscopy using sidestream dark field imaging, which assessed vascular density, the perfused boundary region (PBR), red blood cell velocity (VRBC), and the microvascular health score (MVHS) in small blood vessels.
- Main Results: The study revealed a significant reduction in vascular density in Long COVID patients, particularly in very small capillaries. This decrease in capillary density was not observed in healthy controls. The data showed that the number of capillaries perfused in Long COVID patients was similar to critically ill COVID-19 patients and did not adequately respond to changes in tissue metabolic demand. The MVHS, a measure of microvascular health, was markedly reduced in Long COVID patients compared to healthy individuals.
Conclusions: The findings strongly suggest persistent capillary rarefaction, or a reduction in the number of capillaries, in Long COVID patients even 18 months after the initial infection. The long-term reversibility of this microvascular damage remains uncertain. The study emphasizes the need for further research to understand the extent, potential reversibility, and clinical implications of these lasting microvascular changes in Long COVID.