Mechanical circulatory support: balancing bleeding and clotting in high-risk patients

Abstract

Mechanical circulatory support (MCS) provides a bridge to heart transplant in children and adults with life-threatening heart failure and sustains patients ineligible for transplant. Extracorporeal membrane oxygenation (ECMO) provides temporary support for patients in cardiac or pulmonary failure through external gas exchange and continuous flow of blood. Because the median time to heart transplant exceeds event-free time on ECMO, pulsatile left ventricular assist devices (LVADs) are used to support infants and children. Continuous flow LVADs are preferred in adolescents and adults due to increased pump durability and improved overall survival. The shear stress created by the mechanical pumps cause changes in the hematologic system; acquired von Willebrand syndrome occurs in almost all patients treated with MCS. Despite the improvements in survival, major bleeding occurs in one-third of patients with a LVAD and ischemic stroke and LVAD thrombosis can affect 12% of adults and 29% of children. An antithrombotic strategy to mitigate LVAD bleeding and thrombotic complications has been tested in a randomized trial in children, but intensity of antithrombotic therapy in adults varies widely. Consensus guidelines for antithrombotic therapy during ECMO were created due to significant differences in management across centers. Because of the high risk for both bleeding and thrombotic complications, experts in hemostasis can significantly impact care of patients requiring mechanical circulatory support and are a necessary part of the management team. Learning Objectives• Understand available options for mechanical circulatory support and the impact of mechanical circulatory support on the hematologic system • Differentiate the bleeding and thrombotic risks between children and adults requiring mechanical circulatory support • Recognize possible treatment options for mechanical circulatory support thrombosis Heart failure affects Ͼ5 million adults in the United States (US) and 23 million people globally. 1 The incidence of heart failure in children is significantly less than adults with ϳ18 admissions per 100 000 children per year; however, there is significant economic impact of pediatric heart failure given the frequent need for surgical intervention and the loss of productive years in the event of a child's death. 2 The heart failure etiology also differs with age as most children have congenital heart disease and adults experience cardiomyopathy or coronary artery disease. 1

Direct thrombolysis of multiple thrombi in both right and left heart atrium in a patient on extracorporeal membrane oxygenation support following urgent double-lung transplantation: a case report

“… 14 ECMO carries a high risk for both bleeding and thrombotic complications. 6 , 7 Massive thrombosis in the early postoperative period can be a severe complication in transplant surgery. 8 Catheter-related atrial thrombosis is a potentially deadly complication of intravascular devices.…”

“… 9 Hemodynamic status remains the most important short-term prognostic factor for patients with acute massive thrombosis. 6 In concordance with the use of thrombolytic therapy recommendation for patients with acute symptomatic pulmonary embolism, we decided to thrombolyse with tissue plasminogen activator. 8 , 15 , 16 In this setting, the hemodynamic benefits of thrombolytic treatment far outweigh its risk for bleeding.…”

“… 6 Due to the high risk in all patients with the ECMO support, including the lung transplant patients for both bleeding and thrombotic complications, which can reach 5%, experts in hemostasis can significantly affect the care of patients requiring mechanical circulatory support, and are a necessary part of the management team. 6 , 7 Massive thrombosis in the early postoperative period can be a severe complication in transplant surgery. 8 Catheter-related atrial thrombosis is a potentially deadly complication of intravascular devices.…”

Adult cardiac veno-arterial extracorporeal life support (VA-ECMO): prevention and management of acute complications

“…Anticoagulation monitoring varies at sites and includes ACT, aPTT, and anti-Xa levels. Thromboelastogram (TEG) is sometimes used to evaluate platelet function, however, not all centers routinely use this test (20,23,24).…”

Facilitating noncardiac surgery for the patient with left ventricular assist device: A guide for the anesthesiologist

“…[ 47 ] Over 50% of patients with CF-LVAD have bleeding from gastrointestinal tract (BGIT), with a readmission rate ranging between 1.6 and 2.5 admissions per patient year. [ 13 20 48 49 ] The most common sites of BGIT were the stomach (40%), duodenum (25%), and jejunum (15%). [ 49 ] Patients with BGIT may have had previous BGIT from the same site, from the upper GIT, and be of an older age.…”