The investigators developed a platelet transfusion saving strategy based on thrombopoietin administration in heart or lung transplantation (HLT) patients or assist device implantation in bridge-to-transplantation (BTT) or bridge to-decision (BTD). This strategy was applied from May 2014 to October 2015 in patients whose platelet counts were below 100 Giga per liter (G/L). As part of a health care quality improvement project, the investigators evaluated this strategy in a before/after design. January 2010 to December 2013 constituted the before period.

In may 2014, after Heart or Lung transplantation or assist device implantation, the investigators decided to off-label administered Romiplostim in patients with thrombocytopenia below 100 Giga per liter. The purpose was to reduce platelets transfusion side effects. Romiplostim was used off treatment algorithm was based on previously published data in idiopathic, thrombocytopenia, cirrhotic and hematological patients. The first subcutaneous injection of 1.5 to 2 μg/kg of romiplostim was administered in the postoperative periods. An algorithm based on patient weight and platelet count evolution was established to determine romiplostim doses to administered weekly. Romiplostim posology was adjusted between 2 and 5μg/kg according to platelet count with a maximum of 4 administrations in the ICU. If platelets remained below 50 Giga per liter after 2 injections, bone marrow analysis after hematologist referral was discussed. Platelet count until day 15 after the last injection was monitored to detect thrombocytosis.

In January 2016, the investigators decided to retrospectively assess Romiplostim implementation in the standard of care in the ICU through a Healthcare quality improvement project in a before/after design.

Inclusion Criteria:

• Patients admitted in ICU after HLT, BTT or BTD assist device implantation with platelet counts below 100G/L at least once in the post-operative period

Exclusion Criteria:

• age under 18 or over 65, combined heart and lung transplantation, multiple organ dysfunction syndrome (MODS), pericardial effusion, active surgical bleeding, assist device dysfunction or suspected/diagnosed heparin-induced thrombocytopenia. We also excluded patients with myelodysplastic or myeloproliferative syndrome, hematological malignancy, severe liver cirrhosis with a Child-Pugh score superior to 6, receiving antiplatelet therapy, aplasia diagnosed on bone marrow analyses, pregnancy, thrombophilia, prior pulmonary embolism or stroke in the previous 6 months. Thrombophilia was defined as factor V Leyden mutation, activated protein C resistance, protein S deficiency, protein C deficiency, prothrombin gene mutation, factor VIII excess, ATIII deficiency or antiphospholipid syndrome. For the assistance population, the protocol also excluded destination-therapy devices or patients with transplantation contraindications

Heart or lung transplantation (HLT) patients or assist device implantation in bridge-to-transplantation or to-decision; with platelet counts below 100G/L at least once in the post-operative period