[Possible vaccine-induced immune thrombotic thrombocytopenia in a patient with diabetes and chronic kidney disease or random association?].

We report the case of a 75-year-old man who developed acute myocardial infarction 12 hours after the first dose of ChAdOx1 nCov-19 vaccine. The event was associated with a transient decrease of platelet count and the detection of anti-PF4 antibodies approximately 45 days after the event. Vaccine-induced thrombotic thrombocytopenia (VITT) is characterized by the onset of venous or arterial thrombosis in temporal relationship to the administration of anti-Sars-Cov-2 viral vector vaccines (ChAdOx1 nCov-19 and Ad26.COV2.S), thrombocytopenia and the production of anti-PF4 antibodies. It occurs mainly at a young age, even if the median age is 54 years; it is often associated with thrombosis in atypical sites, such as the cerebral sinus. Our reported case does not present all the diagnostic criteria of VITT. However, the close temporal relationship between ChAdOx1 nCov-19 vaccine administration, thrombosis, and concomitant anti-PF4 antibodies positivity makes the case suggestive of a possible slight form of VITT.