May-Hegglin Anomaly (MHA): A Rare Platelet Disorder Presenting for Coronary Artery Bypass Grafting, Managed With Post-bypass Administration of Platelets and Desmopressin.

May-Hegglin anomaly (MHA) is a hematologic disorder defined by large platelets (mean platelet volume >12.5 fL) and thrombocytopenia. While it remains unclear whether these patients exhibit clinical coagulopathy, bleeding complications may be confounded in those undergoing cardiac surgery requiring cardiopulmonary bypass (CPB). There are no current guidelines for the perioperative management of patients with MHA. Although some reports favor no treatment, limited case reports have described desmopressin (DDAVP) and platelet transfusion as additional strategies. Thromboelastography® with Platelet Mapping™ (TEG-PM) is one modality capable of monitoring coagulation, which can help guide intraoperative blood product transfusions, particularly in patients with underlying platelet disorders. We report the successful management of a 70-year-old female with a history of MHA who presented for CABG and exhibited persistent bleeding despite adequate heparin reversal with protamine. A post-protamine TEG and TEG-PM were obtained. Prior to sternal closure, platelets were requested to treat ongoing bleeding. While the post-protamine TEG appeared normal, TEG-PM demonstrated platelet inhibition, prompting consideration of DDAVP. As a result, both platelets and DDAVP were administered, leading to hemostasis and cessation of bleeding. Given the limited data, patients with MHA should undergo a thorough perioperative hematologic evaluation, including a history of prior bleeding episodes in addition to conventional laboratory studies. Although an increased risk of hemorrhage has not been definitively demonstrated, preparation with blood products and DDAVP should be considered when a heightened risk of surgical coagulopathy exists, such as during cardiac surgery. In our case, we utilized TEG-PM as an additional tool to evaluate hemostasis, which guided the combined use of platelets and DDAVP. While future studies are needed to assess the utility of TEG-PM in the MHA population, it remains important to consider all available technologies to evaluate potential coagulopathy on an individualized basis.