Pharmacologic Considerations in the Management of Patients Receiving Left Ventricular Percutaneous Mechanical Circulatory Support

Abstract

Percutaneous mechanical circulatory support (MCS) devices, including the intraaortic balloon pump, Impella, and TandemHeart, are often used for hemodynamic support in the setting of refractory cardiogenic shock. The thrombotic and bleeding complications associated with these devices is well recognized, and the Impella and TandemHeart devices have unique anticoagulation considerations that may influence patient outcomes. Both devices typically require use of a heparinized purge solution in combination with intravenous unfractionated heparin, thereby providing multiple sources of heparin exposure. Each device also has specific monitoring requirements and goal ranges. This review provides an overview of percutaneous MCS devices commonly used in the acute management of left ventricular failure, with an emphasis on pharmacologic considerations. We review recent evidence and guidelines and provide recommendations for appropriate use of anticoagulation during device support. Approaches to managing heparinized purge solutions, monitoring, and the utility of nonheparin anticoagulants are also provided because high-quality evidence in the literature is limited.

Survey of Anticoagulation Practices with the Impella Percutaneous Ventricular Assist Device at High-Volume Centers

“…Consistent with our expectations, we found that practices varied considerably, even among this cohort of high-volume centers. This is not surprising given that the anticoagulation strategies used in clinical trials are often unclear or have varied across studies [8]. For example, in the ISAR-SHOCK trial comparing the Impella device to IABP in patients with cardiogenic shock after myocardial infarction, a dextrose-only purge solution was used and IV UFH was titrated to target an aPTT of 60-80 seconds [3].…”

“…Distribution of UFH to the peripheral circulation also results in systemic drug exposure [8]. However, the extent to which the purge solution contributes to systemic anticoagulation can vary, thus concurrent administration of intravenous (IV) UFH is also recommended (goal activated clotting time of 160-180 seconds) [6].…”

“…Altogether these factors make the management of anticoagulation during Impella support a considerable challenge. Minimal guidance is provided in the literature, as the anticoagulation practices used in clinical trials have either varied or have not been clearly reported [8]. Also lacking are recommendations in patients with contraindications to UFH such as heparin-induced thrombocytopenia (HIT).…”

Anticoagulation of a Percutaneous Left Ventricular Assist Device Using a Low-Dose Heparin Purge Solution Protocol: A Case Series

“…13 The clinical implications of these faster flow rates are largely unelucidated, but lower concentrations of heparin have been recommended despite manufacturer standards of 50 units/mL. 4 In a recent publication, Dietrich and Kazmi discuss a retrospective cohort analysis of 12 patients evaluating heparin 50 units/mL in D5W versus heparin 50 units/mL in D20W. 5 No differences were observed between D5W and D20W with regard to supratherapeutic aPTT, reduction in heparin concentration, or bleeding events although all the rates were nonsignificantly higher in the D5W cohort.…”

“…Some patients may require supplemental heparin while others have the risk of over anticoagulation with the purge solution alone. 4 To optimize anticoagulation, clinicians have the option to reduce the concentration of heparin in the purge solution. Although the manufacturer recommends a concentration of heparin 50 units/ mL, very little information is available to support the use of a specific heparin concentration, and alternative concentrations have been proposed based on small case series.…”