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

Brent N Reed,Robert J Didomenico,J Erin Allender,Daniel Johnson,Douglas L Jennings,Jenna F Cox,James C Coons,Carrie S Oliphant

doi:10.1155/2019/3791307

Abstract

Objectives To characterize anticoagulation practices with the Impella percutaneous ventricular assist device (pVAD). Background Managing anticoagulation in patients being supported by the Impella pVAD is made challenging by several unique features of the device. These include the release of a dextrose-based purge solution containing unfractionated heparin (UFH), the need to concurrently administer systemic anticoagulation with intravenous UFH, and the lack of an alternative strategy in patients with contraindications to UFH. Methods To characterize anticoagulation practices with the Impella pVAD, we conducted a survey of centers in the United States performing a high volume of Impella cases, which we defined as > 1 per month. Centers were contacted via email or phone and individuals who agreed to participate were provided with a link to complete the survey online. The primary measures of interest were variations in practice across centers and variations from the manufacturer's recommendations. Results Practices varied considerably among respondents (65 of 182 centers, or 35.7%) and often diverged from manufacturer recommendations. Approximately half of centers (52.4%) reported using a UFH concentration of 50 units/mL in the purge solution, whereas most of the remaining centers (41.3%) reported using lower concentrations. Strategies for the initiation and adjustment of systemic therapy also varied, as did practices for routinely monitoring for hemolysis. Nearly one-fifth of centers (16.7%) had not developed an alternative strategy for the purge solution in patients with contraindications to UFH. Most centers (58.4%) reported using argatroban or bivalirudin in this scenario, a strategy that diverges from the manufacturer's recommendations. Conclusions Given these findings, studies to determine a systematic approach to anticoagulation with the Impella device are warranted.

Highlights

Percutaneous ventricular assist devices such as the Impella series (Abiomed; Danvers, MA) may be used for short-term mechanical circulatory support (MCS) during high-risk procedures, or as a bridge to recovery or advanced therapies in patients with cardiogenic shock [1, 2]
In the ISAR-SHOCK trial comparing the Impella device to intra-aortic balloon pump (IABP) in patients with cardiogenic shock after myocardial infarction, a dextroseonly purge solution was used and IV unfractionated heparin (UFH) was titrated to target an Activated partial thromboplastin time (aPTT) of 60-80 seconds [3]
In the PROTECT-II trial comparing the two devices during highrisk percutaneous coronary intervention (PCI), either UFH or bivalirudin could be used for systemic anticoagulation and no information was provided regarding the content of the purge solution [4]

Summary

Introduction

Percutaneous ventricular assist devices (pVADs) such as the Impella series (Abiomed; Danvers, MA) may be used for short-term mechanical circulatory support (MCS) during high-risk procedures, or as a bridge to recovery or advanced therapies (e.g., durable MCS) in patients with cardiogenic shock [1, 2]. One unique facet of Impella devices is the release of a dextrose-based purge solution from the motor housing (Figure 1). The purge solution flows countercurrently to blood flow, creating a pressure barrier to prevent blood from entering the motor housing. Purge solution Pressure barrier Blood flow the purge solution contain 50 units/mL of unfractionated heparin (UFH). Since flow rates of the purge solution are automatically regulated by the device to maintain a specific pressure range (300-1100 mm Hg), UFH exposure may vary considerably in a 24-hour period [6, 7]

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Conclusion