These patients experience an astonishing array of more than 200 symptoms, such as dizziness, diarrhea, shortness of breath, fatigue, and debilitating brain fog, which can persist for months or even years. Disappointingly, even long-term COVID patients who describe breathing-related problems show normal results on standard clinical breathing tests, says pulmonologist Michael Nicholson of St. Louis. Joseph’s Health Care London. But a new imaging technique has now clearly revealed the source of the respiratory problem. “Our findings show that there was a normal impact [patient] lungs that were associated with their symptoms, “says Nicholson. (Alexander Matheson) Scans show the extensive damage that COVID-19 can cause to our sensitive respiratory organs. Whether it is the virus itself or the body’s response to it, a mechanism has effectively curtailed the function of patients’ lungs, removing many of the smaller ones where the very important gas exchange takes place. The researchers, led by physicist Alexander Matheson of Western University, instructed 40 volunteers – 34 with post-acute COVID-19 syndrome and 6 without – to inhale a polarized foreign gas isotope. The gas echoes at a characteristic frequency under magnetic resonance imaging, allowing researchers to observe the activity of tiny airways and blood vessels in real time. “For those who are symptomatic after COVID-19, even if they did not have a serious enough infection to be treated, we see this abnormality in the exchange of oxygen through the alveolar membrane in red blood cells,” says Grace Parraga, a biophysicist at Western University School of Medicine. “What we saw on MRI was that the passage of oxygen to the red blood cells was depressing in these symptomatic patients who had COVID-19, compared with healthy volunteers.” Because flu symptoms are the most obvious and common signs of COVID-19, it is often dismissed as another respiratory illness, but COVID-19 is actually also a vascular disease, which means it can affect the circulatory system. The virus particles directly target the endothelial cells, which line the walls of our blood vessels and heart. Vascular damage is reflected by MRI scans. Computed tomography scans also confirm abnormalities in the thinnest blood vessels in our lungs. In addition, a previous study has already shown a shift in the distribution of blood from smaller to larger blood vessels in the lungs of COVID-19 patients. The team suggests several possible mechanisms for the change in the gas exchange they saw, illustrated in the diagram below. Possible mechanisms for disturbed gas exchange. (Matherson et al., Radiology, 2022) Vessels may lose their flexibility, which reduces the amount of blood available to connect the foreign to the (B), new blood flow patterns thanks to changes in the vessels elsewhere can remove blood from the gas exchange areas (C) or there is a natural blockage that prevents blood from reaching there (D). Matheson and colleagues warn that the small sample size limits their ability to generalize, but urges further research. And whatever the mechanism behind it, it is clear that viral infection can actually cause circulatory problems. Despite easing restrictions in many parts of the world, the global pandemic is still ongoing and any SARS-CoV-2 infection is at risk for vascular damage, from coagulation problems to heart disease. “I was on oxygen for almost two months after COVID and it took me almost three months to get to a place where I could go for a walk without gasping for breath,” explains one of the study participants, bobsled gold medalist Alex Kopacz. . “The message for me is that we need to remember that this virus can have very serious long-term consequences, which are not insignificant. In my case, before I got sick, I did not think it would really affect me. “ This research was published in Radiology.
