Vaccine-induced immune thrombotic thrombocytopenia with atypical vein thrombosis: Implications for clinical practice

Objectives: Vaccine-induced immune thrombotic thrombocytopenia (VITT) is a new and rare syndrome resulting from the largest vaccination campaign against SARS-CoV-2 in the history of mankind. The aim of this review is to clarify underlying mechanisms, pathology, diagnosis, and therapy, with the related clinical implications. Methods: We performed a comprehensive literature review in order to collect the clinical and treatment data about patients suffering from VITT. PubMed, Ovid Medline, Ovid EMBASE, Scopus, and Web of Science were screened regarding patients who developed VITT. Last search was launched on June 30th 2021. Results: Abdominal and/or neurological symptoms develop between 5 and 20 days after vaccine administration and do not involve the lower extremities. VITT is suspected if the platelet count is lower than 100.000/mm3 and D-dimer is higher than the age-adjusted range. Medical treatment is mainly based on intravenous immunoglobulins, corticosteroids, and anticoagulant drugs with a short plasma half-life, but the complete avoidance of low molecular weight heparin is recommended. Endovascular treatment and/or decompressive craniectomy might be an option in a minority of cases. Conclusion: Due to widespread vaccination concerns, the vascular specialist and phlebologist are increasingly consulted to prevent or diagnose VITT. The latter has peculiar and completely different localizations, symptoms, and treatment compared to the common pictures of venous thrombosis.