Anticoagulation Management for Impella Percutaneous Ventricular Assist Devices: An Analysis of a Single-Center Experience

Abstract

Background: Impella devices offer temporary mechanical circulatory support for cardiogenic shock. The manufacturer recommends systemic anticoagulation with a target activated clotting time of 160 to 180 s but provides no guidance on how to manage both the heparinized purge solution and the additional intravenous heparin needed to reach this therapeutic range. Previous publications demonstrated a lack of standardization in heparin management for Impella devices. Objective: The purpose of this study was to compare the effectiveness and safety of 2 different heparin protocols for long-term Impella support. Methods: This single-center, retrospective study included adult patients on Impella support for greater than 24 hours. The primary end point was time to therapeutic range measured in hours, from time of implantation to the first of 2 consecutive measurements within the therapeutic range. Secondary end points included percentage of time in therapeutic range, rates of major bleeding, pump thrombosis, hemolysis, and nursing satisfaction. Results: There were 19 patients identified, with 7 using the original protocol and 12 using the revised protocol. Time to therapeutic range was similar between protocols (15.5 vs 12 hours, P = NS). Another 14 patients were managed with patient-specific protocols as a result of bleeding or physician preference. In total, 42% of all patients in this study experienced major bleeding. There were no confirmed thrombosis events. This study was limited by a small sample size. Conclusion and Relevance: Despite using different heparin protocols, outcomes and bleeding events were similar between groups. Future studies are needed to determine the optimal degree of anticoagulation necessary to reduce bleeding risk.

Antithrombotic management for Impella® temporary ventricular assist devices: An analysis of an academic health-system experience

“…9,12 Bleeding events did not correlate with heparin purge solution, overall systemic heparin exposure, or anticoagulation targets when utilizing the aPTT to monitor heparin efficacy in either our study or the prior studies. 4,9 However, we did find an anti-Xa level greater than 0.4 IU/mL to be associated with a risk for bleeding, for those patients that had these values available. Although protocols for anticoagulation are in place, many centers deviate off protocol and decisions are guided by patient-specific factors.…”

“…Despite manufacturer recommendations, large variability exists with respect to selection of heparin purge concentration, use of concomitant intravenous heparin, and choice of monitoring assay, even among large volume Impella ® centers. 3,4 Bleeding is a known and common complication of anticoagulation, but limited data exists to guide decision making regarding anticoagulation strategies in these complex patients.…”

Outcomes of systemic anticoagulation with bivalirudin for Impella 5.0

“…19 The purge solution is utilized to create a pressure barrier against the inflow of blood, preventing blood from entering the motor housing. 17 Interestingly, three of the five patients (60%) on the D5W purge solution required tPA. Though the sample size of D5W purge solution patients is low, the relative use of tPA was much higher in this patient group compared with the BIV purge solution cohort.…”

“…The time to therapeutic PTT was on average 37.7 h. For reference, a recent study comparing two UFH AC protocols during Impella use reported that median time to therapeutic range PTT was 12 h (IQR 11–19) in one cohort, and 15.5 (IQR 5–26) in another cohort. 17 Our study nomograms are displayed in Tables 5 and 6. The relatively longer time to therapeutic range PTT using BIV was explored by our pharmacy team; based on these findings a new dosing protocol was developed and implemented.…”

Optimizing anticoagulation for patients receiving Impella support

“…39 Finally, a recently published abstract of 30 patients under Impella support compared two different low-intensity anticoagulation regimens (goal aPTT 45-55 s or anti-Xa of 0.2-0.4 IU/ml). 40 The aPTT group was associated with higher heparin dosing requirements, increased time to goal range, shorter time in goal range, and more bleeding episodes.…”