Effective anticoagulation for a percutaneous ventricular assist device using a heparin-based purge solution

Abstract

Objective: To report on a series of patients who were successfully anticoagulated with a novel protocol including a heparin-based purge solution.

Case summary: Four patients were supported for a total of 300 hours on the new Impella anticoagulation protocol, which was based on our current nurse-driven cardiology heparin protocol. Three patients were in cardiogenic shock after acute myocardial infarction, and 1 patient was in shock from severe aortic valvular disease. Despite prolonged cardiogenic shock, none of the patients developed significant renal or liver dysfunction while on device support. All 4 patients survived to hospital discharge, and there were no significant bleeding or thromboembolic events. Furthermore, there were no device malfunctions or clotting events within with pump motors. Despite frequent changes to the purge solution flow rate by the Automated Impella Controller, the patients in our cohort had relatively stable activated partial thromboplastin time values.

Discussion: Our novel anticoagulation protocol, which incorporates the heparin included in the purge solution into the total hourly heparin dosage, was successful in the first cohort of patients receiving extended Impella support for cardiogenic shock. Our case series also highlights that the Automated Impella Controller makes frequent adjustments to the purge solution, which depending on the heparin concentration, can result in significant fluctuations in the patient's total hourly heparin dosage. Furthermore, balancing the heparin in the purge solution with the intravenous heparin is important to ensuring adequate anticoagulation in patients supported by the Impella devices in the intensive care unit.

Conclusions: Development of a standardized anticoagulation protocol for the Impella device that factors the heparin-based purge into the total heparin dosage and makes appropriate adjustments based on the fluctuating rate of the purge solution can provide effective anticoagulation to patients receiving extended circulatory support from this device.

Keywords: Impella; anticoagulation; purge solution.