The current study focused on highlighting the relationship between the incidence of pulmonary embolism and COVID-19 disease severity either laboratory or by the CT severity score trying to help in early anticipation, diagnosis, and treatment of complicated COVID-19 infection cases.
The study included 96 patients with COVID-19 infection and suspected to have PE, out of which 40 were positive; meaning 41.7% of patients with suspected PE. The most common symptom was worsening dyspnea with an incidence of 66.7% in this study population. However, it was not statistically significant. The statistically significant symptoms were oxygen desaturation, chest pain, and hemoptysis. A similar study by Kaminetzky et al. [8] showed a PE incidence of 37% which is close to our study. This was higher than Poyiadji et al. [5] who found a 22% incidence of PE between their study group, yet they are also similar to our study which concluded no significant difference in age and gender regarding the incidence of PE.
In this article, we studied the relationship between the D-dimer, ferritin, CRP, WBC count, neutrophil, and lymphocyte count and the incidence of PE which was found insignificant although patients with positive PE showed higher levels of D-dimer and CRP compared to the patients with negative PE. Also, the rising D-dimer was found to be highly significant. This mandates incorporation of the follow-up of D-dimer in the management of patients. This could explain the result demonstrated by Kamunetzky et al. [8] that concluded that only a significant indicator was the D-dimer closest to the incidence of PE. Another study by Garcia-Olivé et al. [9] demonstrated that patients with high levels of D-dimer have a higher probability of developing PE. Poyiadji et al. [5] concluded an increase in the D-dimer level of 6 μg/ml had an odds ratio of 2.7 for developing a PE. However, in controversy to our study, they found a significant difference not only with D-dimer but also with CRP. The patients with high D-dimer and high CRP were more susceptible to develop PE. All these inflammatory markers are alarming the use of anticoagulants as advised by many authors [10,11,12].
The median time to develop PE was found to be 12 days; however, that was statistically insignificant. The duration of illness in our opinion could raise a flag to continuous follow-up of other alarming symptoms and serial measures of D-dimer. The duration in the study done by Garcia-Olivé et al. [9] was 9.7 which is in keeping with our results. This is also similar to Grillet et al. [4] who diagnosed PE at a mean of 12 days from the onset of the symptoms.
The severity of infection detected by CT severity score calculation was found to be not significant with the incidence of PE which is similar to the results concluded by Bompard et al. [1]. However, the progression of the disease was found to be highly significant with the incidence of PE and this was against Bompard et al. [1] who found the higher incidence of CT progression among patients with negative PE. Again, the follow-up of critically ill patients is considered the key to early diagnosis and life-saving for those critically ill patients.
The incidence of segmental PE was higher among our study population with only 3 cases representing 7.5% of the positive cases developed RV strain. This is almost close to the results found by Poyiadji et al. [5] who found more incidence of segmental PE (51% of cases) and the RV strain occurred in 11% of the patients under study.
Limitation
Our study had few limitations; first, a retrospective study was done in one center, and larger multicentric studies are needed to further understand the nature of this novel complex illness and better manage the second wave. We did not include anticoagulation in our study which will be done in future studies.