In the face of emerging infectious diseases, human beings have gone from blank to groping for countermeasures. The effects of infection also have to go through a long period of research. On March 29, local time, a research team from Austria published a new study in the international academic journal Radiology, and CT evidence from people recovering from COVID-19 pneumonia showed that their lungs were damaged. And by the end of the study, the symptoms had persisted for a full year.
The research team assessed the condition of 91 participants, with an average age of 59 years. They were assessed for chest CT lung abnormalities approximately 2, 3, 6 months and 1 year after the onset of SYMPTOMS of COVID-19. Pulmonary performance in each lobe was graded using a CT Severity Score (CTSS) ranging from 0 (normal) to 25 (all lobe involvement).
The paper notes that the radiological manifestations of acute COVID-19 pneumonia are mainly ground glass opacification (GGO) and focal consolidation. Histological changes in the early stages of COVID-19 pneumonia to patchy acute lung injury with alveolar type II cell hyperplasia and enlargement of interveolar capillaries. Previous studies have found that CT follow-up 4-10 weeks after COVID-19 pneumonia shows that 45-63% of patients have abnormal lung parenchyma. However, long-term lung outcome is unclear.
In the study, they found that in an analysis of patients with COVID-19 pneumonia and chest CT follow-up for 1 year, 49 of 91 participants (54%) had CT abnormalities. Of the 49 participants, 2 (4%) received only outpatient treatment, 25 (51%) were treated in general hospital wards, and 22 (45%) were treated in intensive care units (ICUs).
Of the 49 participants, 31 (34 percent) showed subtle subpleural reticulum, ground glass opacification, or both; another 18 participants (20 percent) showed extensive ground glass clouding, reticularity, bronchiectasis, or microcystic changes.
During the study period, 44% (40/91) of participants showed complete elimination of CT abnormalities. The 31 patients with CT abnormalities did not improve further after 6 months.
A-C is CT for a 44-year-old male patient; D-F is ct for a 68-year-old male patient; and G-I is CT for a 79-year-old male patient. From left to right, at onset, follow-up for 2 months, and follow-up for 1 year.
The team also analyzed whether the development of CT abnormalities correlates with imaging markers or disease severity. They caution that it is important to note that assessing CT imaging findings at early follow-up in the acute phase or after acuteization (2 months after symptom onset) can reliably predict the occurrence of CT abnormalities. This observation may have clinical implications for revealing CT patterns early in the disease, which may provide clues to future therapeutic intervention studies, such as evaluating anti-inflammatory or anti-fibrotic drug regimes to prevent obvious sequelae.
The study also notes that until now, persistent lung abnormalities after ARDS (Acute Respiratory Distress Syndrome) can be explained by the harmful effects of lung disease itself and mechanical ventilation. However, the hypothesis that specific COVID-19 triggers interstitial lung disease has also recently been confirmed. The findings provide additional evidence that, in addition to progressing to ARDS or barometric injury, the natural course of COVID-19 pneumonia itself can cause damage to lung structures.
They also compared a long-term follow-up study citing the 2003 outbreak of SARS-CoV. Jiang Baoguo, academician of the Chinese Academy of Engineering and former president of Peking University People's Hospital, and Gao Zhancheng, director of the Department of Respiratory and Critical Care Medicine of Peking University People's Hospital, were published in a study in Bone Research in 2020. The study mentioned that the most serious sequelae after SARS recovery were necrosis of the femoral head and pulmonary fibrosis, and they followed SARS patients for 15 years on lung and bone conditions.
In their observational cohort study, 80 health care workers contracted pneumonia in 2003. In the 15 years from August 2003 to March 2018, 2 patients died and 78 patients were enrolled, for a total of 71 patients who completed 15 years of follow-up.
In terms of the effect on the lungs, the above study noted that the percentage of lung lesions in SARS patients decreased from 2003 (9.40±7.83%) to 2004 (3.20±4.78) %(P
The team from Austria mentioned in this latest study on COVID-19 pneumonia that although their cohorts were shorter follow-up, what was observed was consistent with these previous findings, indicating that CT was abnormally persistent after COVID-19 but subsequently more stable.
They also note that because the number of cases of SARS-CoV is much smaller and the scope of SARS-CoV-2 infection is widespread, direct comparisons need to be carefully considered during the ongoing pandemic phase. The research team concluded that this result highlights the need for early and longitudinal monitoring of patients with COVID-19.