Bivalirudin Versus Unfractionated Heparin in Patients With Cardiogenic Shock Requiring Venoarterial Extracorporeal Membrane Oxygenation

Evaluation of Newly Integrated Bivalirudin Titration Protocol in Patients With Mechanical Circulatory Support

BACKGROUND

Patients with cardiogenic shock or end-stage heart failure can be maintained on mechanical circulatory support (MCS) devices. Once a patient undergoes placement of a device, obtaining and maintaining therapeutic anticoagulation is vital. Guidelines recommend the use of institutional protocols to assist in dosing and titration of anticoagulants.

OBJECTIVE

The purpose of this study was to characterize the use of bivalirudin before and after the implementation of a standardized titration protocol in patients with MCS.

METHODS

A retrospective review of patients who received bivalirudin for MCS (VA ECMO [veno-arterial extracorporeal membrane oxygenation], Impella, or LVAD [left ventricular assist device]) before and after the implementation of the titration protocol into the electronic health record (EHR) was conducted. The primary outcome was to compare the proportion of therapeutic activated partial thromboplastin time (aPTT). Secondary outcomes included number of subtherapeutic and supratherapeutic aPTTs, incidence of bleeding and clotting events, bivalirudin titrations per day, and percentage of patients with therapeutic aPTT level.

RESULTS

A total of 100 patients were included (precohort = 67; postcohort = 33). The proportion of therapeutic aPTTs was significantly higher in the postcohort than that in the precohort (62% vs 48%; P < 0.001). The postcohort had 0% of patients failing to achieve therapeutic aPTT levels. The number of titrations per day was significantly lower in the postcohort, with 1.20 titrations per day versus 1.93 in the precohort (P < 0.001).

CONCLUSIONS

Implementation of the bivalirudin titration nomograms within the EHR significantly increased the number of therapeutic aPTTs, reduced the number of patients who never achieved a therapeutic aPTT, and reduced the required number of titrations per day.

Comparative analysis of oxygenator dysfunction in polymethylpentene oxygenators: A pilot study

INTRODUCTION

Polymethylpentene (PMP) oxygenators serve as the primary oxygenator type utilized for ECMO. With the number of PMP oxygenators available, it has become increasingly important to determine differences among each oxygenator type that can lead to varying metrics of oxygenator dysfunction.

METHODS

This study was a retrospective, single-center analysis of adult patients supported on ECMO between December 2020 to December 2021 with varying PMP oxygenators including the Medtronic Nautilus Smart (Minneapolis, MA), the Eurosets AMG PMP (Medolla, Italy) and Getinge Quadrox-iD and the Getinge Cardiohelp HLS Module Advanced System (Gothenberg, Sweden).

RESULTS

A total of 19 patients were included in our study. 10 patients (52.6%) were supported with a Medtronic Nautilus Smart oxygenator, 5 patients (26.3%) were supported with an Eurosets AMG PMP Oxygenator, and 4 patients (21.1%) were supported with either a Getinge Quadrox-iD oxygenator or Getinge Cardiohelp HLS system. Patients supported with Eurosets AMG PMP oxygenators experienced higher resistance and lower post-oxygenator PaO2 in comparison to other cohorts (p < .02 and < .002 respectively). There was no difference in measured oxygen transfer between cohorts (p = .667). Two patients, both supported by Eurosets AMG PMP, experienced oxygenator failure (p = .094).

CONCLUSION

Radial flow oxygenators are prone to higher resistance and lower post-oxygenator PaO2when compared to transverse flow oxygenators. Future larger multicenter studies are required to fully discern the differences between flow-varying polymethylpentene oxygenators and their appropriate cutoffs for oxygenator dysfunction.

Factors Influencing Successful Weaning From Venoarterial Extracorporeal Membrane Oxygenation: A Systematic Review

With advancements in extracorporeal life support (ECLS) technologies, venoarterial extracorporeal membrane oxygenation (VA-ECMO) has emerged as a crucial cardiopulmonary support mechanism. This review explores the significance of VA-ECMO system configuration, cannulation strategies, and timing of initiation. Through an analysis of medication management strategies, complication management, and comprehensive preweaning assessments, it aims to establish a multidimensional evaluation framework to assist clinicians in making informed decisions regarding weaning from VA-ECMO, thereby ensuring the safe and effective transition of patients.

Concomitant use of extracorporeal membrane oxygenation and percutaneous microaxial assist device support for cardiogenic shock

Objectives

Venoarterial extracorporeal membrane oxygenation (VA-ECMO) with concomitant percutaneous microaxial left ventricular assist device support is an emerging treatment modality for cardiogenic shock (CS). Survival outcomes by CS etiology with this support strategy have not been well described.

Methods

This study was a retrospective, single-center analysis of patients with CS due to acute myocardial infarction (AMI-CS) or decompensated heart failure (ADHF-CS) supported with VA-ECMO with concomitant percutaneous microaxial left ventricular assist device support from December 2020 to January 2023.

Results

A total of 44 patients were included (AMI-CS, n = 20, and ADHF-CS, n = 24). Patients with AMI-CS and ADHF-CS had similar survival at 90 days postdischarge (P = .267) with similar destinations after support (P = .220). Patients with AMI-CS initially supported with VA-ECMO were less likely to survive 90 days postdischarge (P = .038) when compared with other cohorts. Limb ischemia and acute kidney injury occurred more frequently in patients presenting with AMI-CS (P =.013; P = .030). Subanalysis of ADHF-CS patients into acute-on-chronic decompensated HF and de novo HF demonstrated no difference in survival or destination.

Conclusions

VA-ECMO with concomitant percutaneous microaxial left ventricular assist device support can be used to successfully manage patients with CS. There is no difference in survival or destination for AMI-CS and ADHF-CS with this support strategy. AMI-CS patients with initial VA-ECMO support have increased mortality in comparison to other cohorts. Future multicenter studies are required to fully analyze the differences between AMI-CS and ADHF-CS with this support strategy.

Optimal Antithrombotic Strategies in Cardiogenic Shock

Cardiogenic shock (CS) represents a critical condition with a high mortality rate. The most common cause of CS is coronary artery disease, and patients typically present with myocardial infarction, necessitating immediate treatment through percutaneous coronary intervention (PCI) and often requiring mechanical circulatory support. CS is associated with a prothrombotic situation, while on the other hand, there is often a significant risk of bleeding. This dual challenge complicates the selection of an optimal antithrombotic strategy. The choice of antithrombotic agents must be personalized, taking into consideration all relevant conditions. Repeated risk assessment, therapeutic monitoring, and adjusting antithrombotic therapy are mandatory in these patients. This review article aims to provide an overview of the current evidence and practical guidance on antithrombotic strategies in the context of CS.

Anticoagulation strategies in patients with extracorporeal membrane oxygenation: A network meta-analysis and systematic review

OBJECTIVES

Extracorporeal membrane oxygenation (ECMO) plays an important role in providing temporary life support for patients with severe cardiac or pulmonary failure, but requires strict anticoagulation and monitoring. This network meta-analysis systematically explored the most effective anticoagulation and monitoring strategies for patients receiving ECMO.

METHODS

MEDLINE, Embase, Web of Science, and the Cochrane Central Register of Controlled Trials were searched up to January 31, 2023, for studies comparing unfractionated heparin (UFH), argatroban (Arg), bivalirudin (Biv), and/or nafamostat mesylate (NM) in patients receiving ECMO. The primary outcomes included device-related thrombosis, patient-related thrombosis, and major bleeding events. The secondary outcomes included ECMO survival, ECMO duration, and in-hospital mortality.

RESULTS

A total of 2522 patients from 23 trials were included in the study. Biv was associated with a decreased risk of device-related thrombosis (odd ratio [OR] 0.51, 95% confidence interval [CI]: 0.33-0.84) compared with UFH, whereas NM (OR 2.2, 95% CI: 0.24-65.0) and Arg (OR 0.92, 95% CI: 0.43-2.0) did not reduce the risk of device-related thrombosis compared with UFH. Biv was superior to Arg in decreasing the risk of device-related thrombosis (OR 0.14, 95% CI: 0.03-0.51). Biv reduced the risk of patient-related thrombosis compared with UFH (OR 0.44, 95% CI: 0.18-0.85); NM (OR 0.65, 95% CI: 0.14-3.3) and Arg (OR 3.1, 95% CI: 0.94-12.0) did not decrease risk of patient-related thrombosis compared with UFH. No significant difference was observed in the risk of major bleeding between three alternatives and UFH: Biv (OR 0.54, 95% CI: 0.23-1.3), Arg (OR 1.3, 95% CI: 0.34-5.8), and NM (OR 0.60, 95% CI: 0.13-2.6). NM showed a reduced risk of in-hospital mortality compared with UFH (OR 0.27, 95% CI: 0.091-0.77), whereas Arg (OR 0.43, 95% CI: 0.15-1.2) and Biv (OR 0.75, 95% CI: 0.52-1.1) did not decrease risk of in-hospital mortality.

CONCLUSIONS

Compared with UFH and Arg, Biv reduces the risk of thrombosis and appears to be a better choice for patients requiring ECMO. NM was associated with a reduced risk of in-hospital mortality.

Is it time to switch to bivalirudin for ECMO anticoagulation?

For decades, unfractionated heparin (hereafter, heparin) has been the primary anticoagulant used for extracorporeal membrane oxygenation (ECMO) support. More recently, however, bivalirudin, a direct thrombin inhibitor, has emerged as an alternative. This systematic review based on PRISMA guidelines, aims to summarize 16 comparative studies and 8 meta-analysis and review articles published from January, 2011 till May, 2023 which directly compares ECMO courses using heparin versus bivalirudin as the anticoagulant. While this comparison is complicated by the lack of a standardized definition of major bleeding or thrombosis, our overall findings suggest there is no statistical difference between heparin and bivalirudin in incidence of bleeding and thrombosis. That said, some studies found a statistical significance favoring bivalirudin in reducing major bleeding, thrombosis, and the need for transfusions. We also offer essential guidance for appropriately selecting an anticoagulant and monitoring its effect in ECMO settings.

Bivalirudin Compared to Heparin as the Primary Anticoagulant in Pediatric Berlin Heart Recipients

Bivalirudin has been used in increasing frequency as an alternative to unfractionated heparin (UFH) in pediatric recipients of Berlin Heart EXCOR ventricular assist devices (VAD). This single-center, retrospective review characterizes anticoagulant trends and outcomes in pediatric Berlin Heart VAD recipients implanted between September 1, 2013, and August 31, 2021, anticoagulated with either bivalirudin or UFH. Thirty-one patients were included; 65% who received bivalirudin and 35% who received UFH. The median age was 2.9 years, included 64.5% females, with 61.3% of patients diagnosed with dilated cardiomyopathy and 25.8% of patients with congenital heart disease. Therapeutic anticoagulation was achieved sooner in the bivalirudin group compared to UFH via anti-Xa monitoring (median 5.7 and 69.5 hours, respectively, p < 0.001). Bivalirudin had a greater number of therapeutic values comparatively to UFH (52% and 24%, respectively; p < 0.001) and a superior number of hours in the therapeutic range (67% and 32%, respectively; p < 0.001). Secondary outcomes were similar among the two groups, apart from greater chest tube output (UFH), more frequent events of elevated plasma-free hemoglobin (bivalirudin), and more frequent elevated inflammatory markers postimplant (bivalirudin). Prevalence of pump replacements secondary to significant clot burden and prevalence of stroke was comparable. In this patient cohort, bivalirudin demonstrated greater anticoagulation stability comparatively to UFH. Multicenter collaboration would be necessary to identify whether this further translates into improved patient outcomes.

Outcomes of systemic bivalirudin and sodium bicarbonate purge solution for Impella 5.5

BACKGROUND

Impella 5.5 (Abiomed; Danvers, MA) (IMP5) is a commonly used, surgically implanted, tMCS device that requires systemic anticoagulation and purge solution to avoid pump failure. To avoid heparin-induced thrombocytopenia (HIT) from unfractionated heparin (UFH) use, our program has explored the utility of bivalirudin (BIV) for systemic anticoagulation and sodium bicarbonate-dextrose purge solution (SBPS) in IMP5.5.

METHODS

This single center, retrospective study included 34 patients supported on IMP5.5 with BIV based AC and SBPS between December 1st 2020 to December 1st 2021.The efficacy and safety end points were incidence of development of HIT, Tissue Plasminogen Activator (tPA) use for suspected pump thrombosis, stroke, and device failure as well as clinically significant bleeding.

RESULTS

The median duration of IMP5.5 support was 9.8 days (IQR: 6-15). Most patients were bridged to HTX (58%) followed by recovery (27%) and LVAD implantation (15%). Patients were therapeutic on bivalirudin for 64% of their IMP5.5 support. One patient (2.9%) suffered from ischemic stroke and 26.5% (9) patients developed clinically significant bleeding. tPA was administered to 7(21%) patients. One patient in the entire cohort developed HIT.

CONCLUSIONS

Our experience supports the use of systemic BIV and SBPS as a method to avoid heparin exposure in a patient population predisposed to the development of HIT.