Correlation of serum D-dimer level and the event microvessel cardiac thrombosis observed on core biopsy in post mortem COVID-19 Patients in Dr. Soetomo Hospital Surabaya, Indonesia

Background: Microvascular coronary thrombosis is an emerging risk factor that worsens the prognosis of COVID-19 patients. This study aims to show for the first time a descriptive of histopathologic findings from post-mortem COVID-19 patients and to analyze whether D-Dimer serum level, a marker of hyper-coagulopathy, correlates with coronary microvascular thrombosis from the cardiac core biopsy. Method: This was an observational analytic study with a retrospective cohort design from July-December 2020. Cardiac core biopsy was taken from patients who died while treated at the isolation ICU at Dr. Soetomo due to severe COVID-19. The samples were taken in 1-hour post-mortem and then analyzed histopathologically with Hematoxylin-eosin staining under a light microscope to evaluate the presence of coronary microvascular thrombosis and other pathological findings from the cardiac biopsy. Clinical information and D-Dimer levels from medical records and analyzed for coronary microvascular thrombosis using Man-Whitney and C-statistic analysis using SPSS 22 software. Result: There were 39 samples of post-mortem patients in this study. The majority were men (71.8%), with a mean age of 48.9 years old. Focal microvessel coronary thrombosis was found in 28%). The median D-Dimer level was increased from the average baseline (3460 mg/dl). However, there was no significant difference in D-dimer levels between focal microvessel coronary thrombosis incidents (p-value 0.827, C statistic AUC 0.523). The lack of focal necrosis in the surrounding tissue suggests that the thrombosis resulted from proximal embolization to distal capillary coronary, which already happened before, rather than the primary in-situ process in microvascular, hence may explain why D-Dimer was not correlated with the finding of coronary microvascular thrombosis in this study. Conclusion: D-dimer serum levels were not associated with focal microvessel thrombi in post-mortem COVID-19 patients. This result supports previous studies that showed D-Dimer was not specific to detect thrombosis in microvascular.