New study addresses thromboembolic complications in COVID-19 patients


COVID-19There is an “urgent need” to improve specific venous thromboembolism (VTE) diagnostic strategies and investigate the efficacy and safety of thromboprophylaxis in ambulatory COVID-19 patients. This is the conclusion of a recent study into venous and arterial thromboembolic complications in COVID-19 patients admitted to an academic hospital in Milan, Italy.

Behind this conclusion are the investigators’ main findings that a high number of arterial and, in particular, venous thromboembolic events were diagnosed within 24 hours of admission and there was a high rate of positive VTE imaging tests among the few COVID-19 patients tested.

The authors elaborate: “Hospitalised patients with COVID-19 were characterised by substantial in-hospital mortality and a high rate of thromboembolic complications. Rapidly increasing D-dimer levels were observed in non-survivors, reflecting the inflammatory and procoagulant state of COVID-19.”

The study, authored by Corrado Lodigiani (Humanitas Clinical and Research Hospital and Humanitas University, Milan, Italy) and colleagues—on behalf of the Humanitas COVID-19 Task Force—was recently published in Thrombosis Research.

Lodigiani and colleagues note that few data are available on the rate and characteristics of thromboembolic complications in hospitalised patients with COVID-19.

The Humanitas COVID-19 Task Force studied consecutive symptomatic patients with laboratory-proven COVID-19 admitted to a university hospital in Milan, Italy. They detail that the primary outcome was any thromboembolic complication, including VTE, ischaemic stroke, and acute coronary syndrome/myocardial infarction and that the secondary outcome was overt disseminated intravascular coagulation.

Lodigiani et al report that, of 388 patients (median age 66 years, 68% men, 16% requiring intensive care [ICU]), thromboprophylaxis was used in 100% of ICU patients and 75% of those on the general ward. Thromboembolic events occurred in 28 (7.7% of closed cases; 95% CI 5.4–11%), corresponding to a cumulative rate of 21% (27.6% ICU, 6.6% general ward). Half of the thromboembolic events were diagnosed within 24 hours of hospital admission.

Forty-four patients underwent VTE imaging tests and VTE was confirmed in 16 (36%). Computed tomography pulmonary angiography was performed in 30 patients, corresponding to 7.7% of total, and pulmonary embolism was confirmed at 10 (33% of computed tomography pulmonary angiography). The rate of ischaemic stroke and acute coronary syndrome/myocardial infarction was 2.5% and 1.1%, respectively. Overt disseminated intravascular coagulation was present in eight (2.2%) patients.

The authors acknowledge limitations to the present study. “This was a retrospective analysis conducted at a large university hospital, therefore possibly not reflecting the management strategies and diagnostic facilities at other non-academic institutions,” they note.

Furthermore, the authors address a geographical limitation: “Patients included in this analysis were diagnosed at one of the ‘red zones’ where the European outbreak started. This may have influenced not only patients’ outcome, as no global experience on the disease was available yet, but also the execution and frequency of imaging tests during hospitalisation. From this perspective, we could not confirm whether thromboembolic events contributed substantially to such a dramatic mortality and no autopsies were routinely performed in COVID-19 patients. Indeed, we showed that the D-dimer levels, a marker of inflammation and coagulation activation, rapidly increases in non-survivors during the course of hospitalisation; overt disseminated intravascular coagulation was present in 2% of COVID-19 patients and fatal in almost all cases.”


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