Hypercoagulability and reduced fibrinolysis are well-established complications associated with COVID-19. However, the timelines for the onset and resolution of these complications remain unclear. The aim of this study was to evaluate, in a cohort of COVID-19 patients, changes in coagulation and fibrinolytic activity through ROTEM assay at different time points during the initial 30 days following the onset of symptoms in both mild and severe cases. Blood samples were collected at five intervals after symptoms onset: 6–10 days, 11–15 days, 16–20 days, 21–25 days, and 26–30 days. In addition, fibrinogen, plasminogen, PAI-1, and alpha 2-antiplasmin activities were determined. Out of 85 participants, 71% had mild COVID-19. Twenty uninfected individuals were evaluated as controls. ROTEM parameters showed a hypercoagulable state among mild COVID-19 patients beginning in the second week of symptoms onset, with a trend towards reversal after the third week of symptoms. In severe COVID-19 cases, hypercoagulability was observed since the first few days of symptoms, with a tendency towards reversal after the fourth week of symptoms onset. A hypofibrinolytic state was identified in severe COVID-19 patients from early stages and persisted even after 30 days of symptoms. Elevated activity of PAI-1 and alpha 2-antiplasmin was also detected in severe COVID-19 patients. In conclusion, both mild and severe cases of COVID-19 exhibited transient hypercoagulability, reverted by the end of the first month. However, severe COVID-19 cases sustain hypofibrinolysis throughout the course of the disease, which is associated with elevated activity of fibrinolysis inhibitors. Persistent hypofibrinolysis could contribute to long COVID-19 manifestations.

高凝状态和纤溶减少是与 COVID-19 相关的明确并发症。然而，这些并发症的发生和解决的时间表仍不清楚。本研究的目的是通过 ROTEM 检测评估一组 COVID-19 患者在轻度和重度病例出现症状后最初 30 天内不同时间点的凝血和纤溶活性的变化。症状出现后每隔五个时间间隔采集血样：6-10 天、11-15 天、16-20 天、21-25 天和 26-30 天。此外，还测定了纤维蛋白原、纤溶酶原、PAI-1 和 α2-抗纤溶酶活性。在 85 名参与者中，71% 患有轻度 COVID-19。二十名未感染者被评估为对照。 ROTEM 参数显示，轻度 COVID-19 患者从症状出现第二周开始就处于高凝状态，并在症状第三周后出现逆转趋势。在严重的 COVID-19 病例中，自症状出现的最初几天起就观察到高凝状态，并在症状出现第四周后有逆转的趋势。严重的 COVID-19 患者从早期就发现纤溶低下状态，甚至在出现症状 30 天后仍持续存在。在重症 COVID-19 患者中也检测到 PAI-1 和 α2-抗纤溶酶活性升高。总之，轻度和重度 COVID-19 病例均表现出短暂的高凝状态，并在第一个月末恢复。然而，严重的 COVID-19 病例在整个病程中持续存在纤溶低下，这与纤溶抑制剂活性升高有关。持续的纤溶低下可能会导致长期的 COVID-19 表现。