Correlation of chest CT severity score with D-dimer levels in patients with COVID-19

Abstract

Abstract Background Coronavirus disease 2019 (COVID 19) caused by severe acute respiratory syndrome corona virus 2 (SARS-CoV-2) predominantly affects lungs and leads to COVID-19 pneumonia. Studies have shown that COVID 19 is hypercoagulative prothrombotic state. The innate tropism of SARS CoV-2 for vascular endothelial cells and their consequent damage, together with the intense activation of inflammatory responses and of coagulation pathways, may explain the intense pro-coagulative state. It ultimately predisposes to systemic micro-thrombotic alterations and gives rise to the consistent rate of multi-organ failure, DIC and ARDS in severe COVID-19 patients. Purpose Aims of this retrospective study were to determine the correlation between a CT-based semi-quantitative score of pulmonary involvement in COVID-19 pneumonia with D-dimer and CRP levels. Materials and methods 174 symptomatic SARS-CoV-2 patients were enrolled from August 4 to October 12, 2020, for this single-center analysis in rural India and chest CT examinations were retrospectively evaluated. The COVID 19 positivity was defined on the basis of RTPCR done at ICMR (Indian Council of Medical Research) approved laboratory. A semi-quantitative CT score was calculated based on the extent of lobar involvement (0:0%; 1: <5%; 2: 5–25%; 3: 26–50%; 4: 51–75%; 5: >75%; range 0–5; global score 0–25). D-dimer and CRP were done at the time of admission. One way ANOVA and post hoc Tukey test were performed to compare the variables of Chest CT score in percentage to various other variables. Results CT score had significant positive correlation with D-dimer levels (p=0.002, r: 0.237). CT score was significantly correlated with CRP (p<0.001, r: 0.392) levels. Subgroup analysis by post hoc Tukey test further showed that D-dimer levels were significantly elevated in 51–75% and >75% lobar involvement groups on Chest CT with statistically significant p value of <0.001. Conclusions This study data suggests that CT score has significant positive correlation with D-dimer and CRP. D-dimer is significantly elevated in the group where lobar involvement is more significant on Chest CT. D-dimer is an indirect marker of active coagulation and thrombin formation. Elevated D-dimer represents activation of endovascular thrombotic processes. This hypercoagulative infection-induced state is systemic, and may lead to various clinical manifestations such as myocardial infarction, stroke, limb ischemia and DIC. Monitoring of pro-thrombotic activity of SARS-CoV-2 with tests such as D-dimer, with consequent labelled administration of adjusted doses of anticoagulants are of paramount importance in order to prevent worsening of global conditions due to vascular parenchymal or systemic thrombotic dysfunction in COVID-19 patients. Funding Acknowledgement Type of funding sources: None.