EComment. Platelet transfusion after aortic valve replacement by the Freedom Solo bioprosthesis

Abstract

I read with great interest the article by Repossini and colleagues [1] regarding postoperative platelet reduction after the implantation of Freedom Solo, a stentless pericardial bioprosthesis. Within a larger cohort of patients, the authors confirmed data already published [2-3] by showing a significant reduction and a slower recovery of platelet counts during the first postoperative week after implantation of the Freedom Solo bioprosthesis. This concise phenomenon was not associated with clinical consequences (no major haemorrhagic or thromboembolic events during hospitalization) or haemodynamic dysfunction of the implanted valve. The authors showed that compared to patients with normal platelet counts, patients with any degree of preoperative thrombocytopenia had an increased odds ratio of 8.69 of being in the group with platelet count <150x103/mm3. I think there are some points that should be emphasized. Did patients receive platelet concentrates? On the third day after surgery, 20.7% of their patients showed severe or very severe thrombocytopenia. It is needless to say that platelet transfusion would have been considered in these patients before retrieval of catheters or epicardial leads. Platelet transfusion is associated with an increased likelihood of postoperative infection and transfusion-related acute lung injury (TRALI), which is a potentially fatal complication [4]. Alfirevic and colleagues [5] recently demonstrated that platelet transfusion after cardiac surgery increased the prevalence of vasoplegia and therefore increased morbidity. In considering the clinical implications of these findings, the practice of implanting a Freedom Solo in patients with preoperative thrombocytopenia is not justified. It is also important to be aware of the increased risk of thrombocytopenia after aortic valve replacement by the Freedom Solo prosthesis and patients should be informed about this possibility. In the interim, research into the exact mechanism behind postoperative thrombocytopenia after implantation of the Freedom Solo valve is ongoing, and efforts to limit the risks of infection and TRALI to our patients by reducing platelet transfusion are warranted. Conflict of Interest: None declared