Variable serotonin release assay pattern and specificity of PF4-specific antibodies in HIT, and clinical relevance.

Background: The diagnosis of heparin-induced thrombocytopenia (HIT) requires functional assays to demonstrate that platelet factor 4 (PF4)-specific antibodies activate platelets, typically when therapeutic heparin (H) concentrations are tested ("classical" pattern). Some HIT samples also activate platelets without heparin ("atypical" pattern), but with unclear clinical significance.

Objectives: We aimed to assess whether platelet activation pattern and some characteristics of PF4-specific antibodies were associated with the severity of HIT.

Frequency and Clinical Impact of Platelet Factor 4-Specific Antibodies in Patients Undergoing Extracorporeal Membrane Oxygenation.

Introduction/objectives:  Extracorporeal membrane oxygenation (ECMO) provides circulatory support in patients with severe heart failure, but the frequent use of unfractionated heparin exposes patients to high risk of heparin-induced thrombocytopenia (HIT). We prospectively evaluated the development and clinical impact of platelet factor 4 (PF4)-specific antibodies (Abs) during ECMO and whether specific biological characteristics could predict HIT.

Materials And Methods:  From 2014 to 2018, we studied 57 adults who underwent an ECMO for at least 5 days.

Very long-term outcomes of the Carpentier-Edwards Perimount valve in aortic position.

Background: The Carpentier-Edwards Perimount pericardial bioprosthesis (Edwards Lifesciences, Irvine, CA) has demonstrated good long-term outcomes, but its durability remains unclear depending on age at implantation. We report our 20-year experience with the Perimount valve implanted in the aortic position, with particular attention to the probability and time to reoperation required due to bioprosthesis deterioration.

Methods: From 1984 to 2008 at our center, 2,659 patients (mean age, 70.

Carotid artery stenting using a transapical approach for the treatment of radiation-induced carotid stenosis.

Radiation-induced stenosis of the carotid artery is considered a challenging entity for direct revascularization. We performed a carotid artery stenting for a radiation-induced stenosis using a transapical approach on an asymptomatic 63-year-old male patient. Transapical approach, which is often used for cardiac surgery, was not yet described for the endovascular treatment of carotid stenosis.

Incidence of antibodies to protamine sulfate/heparin complexes incardiac surgery patients and impact on platelet activation and clinical outcome.

A new ELISA (Zymutest HIA®), based on incubation of diluted plasma with protamine/heparin (PRT/H) complexes without and with platelet factor 4 (PF4) provided by a platelet lysate, was used to detect heparin-dependent antibodies in a cohort of 232 cardiac surgery (CS) patients and in 47 patients with heparin-induced thrombocytopenia (HIT). Significant binding of IgG/A/M to PRT/H complexes was demonstrated in 59 CS patients (25.4%), with similar absorbances whether platelet lysate was added to the plasma or not, and significant reactivity to PF4/H in 29 of them.

Polymorphisms of protein tyrosine phosphatase CD148 influence FcγRIIA-dependent platelet activation and the risk of heparin-induced thrombocytopenia.

Heparin-induced thrombocytopenia (HIT) is due primarily to IgG antibodies specific to platelet factor 4/heparin complexes (PF4/Hs) that activate platelets via FcγRIIA. CD148 is a protein tyrosine phosphatase that regulates Src kinases and collagen-induced platelet activation. Three polymorphisms affecting CD148 (Q276P, R326Q, and D872E) were studied in HIT patients and 2 control groups, with or without antibodies to PF4/Hs.

A 25-year experience with Carpentier-Edwards Perimount in the mitral position.

Data of 401 patients who underwent mitral valve replacement with the Carpentier-Edwards Perimount bioprosthesis between 1984 and 2009 were evaluated. Their mean age was 68.1 ± 10.

Changes in platelet count after cardiac surgery can effectively predict the development of pathogenic heparin-dependent antibodies.

Cardiopulmonary bypass (CPB) induces the release of platelet factor 4 (PF4) and patients are at risk of heparin-induced thrombocytopenia (HIT). This study was aimed to determine whether an abnormal evolution in platelet count (PC) after CPB is predictive of the development of HIT antibodies. Two abnormal PC patterns were defined: pattern P1, characterized by a decrease in PC following previous correction of thrombocytopenia occurring during CPB, and pattern P2, defined as a persistent low PC in the days following CPB.