Heparin-Induced Thrombocytopenia under Mechanical Circulatory Support by Large Impella for Acute Cardiogenic Shock

Despite the critical feature of heparin-induced thrombocytopenia (HIT) for patients on mechanical circulatory support, reports on its incidence and outcome are still scarce. Thus, we report on clinical features of HIT in patients under Impella 5.0 or 5.5 (Abiomed Inc., Danvers, MA, USA) (Impella 5+) support for acute cardiogenic shock (CS) by focusing on observed thrombotic events. Between November 2018 and December 2020, a total of 56 consecutive patients were enrolled in a single-center retrospective study. A total of 21 patients (37.5%) were tested for HIT, and 6 (10.7%) proved positive for HIT at 10.5 ± 2.89 days after the first heparin administration during current admission. Interestingly, thrombocyte counts dropped under Impella support in all groups (all cases, no HIT test, and HIT negative group: p < 0.001, HIT-positive group: p = 0.001). All HIT-positive patients were switched from heparin to argatroban. HIT-associated thrombotic events were observed in two cases resulting in Impella dysfunction due to pump thrombosis (n = 1) and left ventricular (LV) thrombus formation (n = 1). Under large Impella support, the prevalence of HIT was relatively high. Further, thrombocytopenia does not deliver a high specificity in the setting of Impella 5+ support. Considering HIT manifestation, a routine HIT test may be considered to avoid critical thrombotic adverse events.

VAD related infections and the risk of pump thrombosis and thromboembolic events: a EUROMACS study

Background In patients supported by a ventricular assist device (VAD) major infections are a frequently reported adverse event with increased morbidity and mortality. Purpose The purpose of this study was to investigate the possible association between infections and cerebrovascular accidents (CVAs) in VAD patients. Methods An analysis of the European Registry for Patients Assisted with Mechanical Circulatory Support (EUROMACS) was performed identifying all patients aged ≥18 years with a LVAD or BiVAD implantation. Infections were categorized as VAD-specific infections, VAD-related infections and, non-VAD infections. An extended Kaplan-Meier analysis for the risk of CVA and mortality with infection as a time-dependent covariate was performed. Furthermore, a multivariable Cox proportional hazard model was performed including 24 variables. Results For this analysis 3784 patients were included, with 45 patients being supported by a BiVAD and 3739 by an LVAD. The majority of patients were male (83.2%) and 60.5% had an INTERMACS patient profile 2 or 3. During follow-up, 3108 major infections were identified in 1385 (36.6%) of the patients, while 673 CVAs were identified in 545 (14.4%) of the patients. Extended Kaplan-Meier analysis with first infection as time-dependent covariate revealed a hazard ratio (HR) for CVA of 1.95 (95% CI: 1.57–2.36; p&lt;0.005) (Figure) and 1.50 (95% CI: 1.33–1.68, p&lt;0.005) for mortality. Multivariable analysis confirmed a significant association for infection and CVAs with a HR of 1.46 (95% CI: 1.29–1.64). With infections subcategorized, VAD-specific (HR: 1.57 (95% CI: 1.18–2.09)) and VAD-related infections (HR: 2.04 (95% CI: 1.44–2.89)) remained significantly associated with CVA but non-VAD infections (HR: 1.22 (95% CI: 0.92–1.64)) were not. Conclusion Both VAD-related and VAD-specific infections are associated with a significantly increased risk of CVA with increased risk of mortality. FUNDunding Acknowledgement Type of funding sources: None. KM freedom of CVA and infection

Use of a Novel Bicarbonate-Based Impella 5.5 Purge Solution in a Coagulopathic Patient

The Impella 5.5 with SmartAssist (Abiomed; Danvers, MA) is a life-saving treatment option in acute heart failure which utilizes a continuous heparin purge solution to prevent thrombosis. In patients with contraindications to heparin, alternative anticoagulation strategies are required. We describe the stepwise management of anticoagulation in a coagulopathic patient with persistent cardiogenic shock following a coronary artery bypass procedure who underwent Impella 5.5 placement. A direct thrombin inhibitor-based purge solution was utilized while evaluating for heparin-induced thrombocytopenia. Use of a novel bicarbonate-based purge solution (BBPS) was successfully used due to severe coagulopathy. There were no episodes of pump thrombosis or episodes of severe bleeding on the BBPS and systemic effects of alkalosis and hypernatremia were minimal.

Association of thrombophilia prospective detection with hemocompatibility related outcomes in left ventricular assist device patients

Introduction: Inherited thrombophilias represent a concerning risk factor due to a proclivity to an aberrant clot formation. However, in patients with left ventricular assist device (LVAD), their impact on bleeding and thrombotic complications remains still poorly understood. The aim of the present study was to evaluate the effect of thrombophilic mutation directed anticoagulation therapy on adverse clinical outcomes in LVAD patients. Materials and methods: About 138 consecutive patients indicated for LVAD implant (HeartMate II, Abbott, Plymouth, USA) were prospectively screened for three major thrombophilic mutations: factor II (prothrombin), factor V Leiden, and homozygous methylenetetrahydrofolate reductase (MTHFR). Subsequently, discordant individualized anticoagulation targets of INR 2.5–3.0 in thrombophilia positive and INR 1.8–2.2 in negative patients were established; notably without anti-platelet agents given the center standard of care. Results: Mean age was 50 ± 12.7 years, 83% male. Mean duration of support was 464.5 days (SD 482.9; SEM 41.1) and median of 310 days (IQR 162; 546). Full thrombophilia positive cohort analysis has not revealed any significant impact on event free survival. In contrast, detailed analysis of specific thrombophilias subsets has revealed Factor II prothrombin mutation as a significant predisposition for the pump thrombosis risk (SHR 10.48; p = 0.001) despite more aggressive prespecified anticoagulation target. Moreover, the incidence of bleeding events in prothrombin group was also significantly increased (SHR 6.0; p = 0.03). Conclusions: Our observations suggest that specific thrombophilias in LVAD patients may pose different intensity predisposition for thrombotic complications. Factor II (prothrombin) positive mutation was identified as significant risk factor associated with the pump thrombosis.

CENTRIFUGAL-FLOW LVAD INFLOW CANNULA POSITION: PREOPERATIVE INFLUENCES AND POSTOPERATIVE OUTCOMES

Background: We previously demonstrated better inflow cannula (IFC) position and reduced pump thrombosis with a centrifugal-flow LVAD (CF-LVAD) compared to an axial-flow device. We hypothesized that implant technique and patient anatomy would affect CF-LVAD IFC positioning and that malposition would impact LV unloading and outcomes. Methods: Pre- and postoperative computed tomography (CT) scans were reviewed for patients with six-month follow-up. Malposition was quantified using angular deviation from an ideal line in two planes. IFC position was compared between conventional sternotomy (CS) and lateral thoracotomy-hemisternotomy (LTHS). The influence of LV end-diastolic dimension (LVEDD), body mass index (BMI), and CT-derived anatomy was determined. LV unloading was assessed by LVAD flow index (FI) and pre- to post-LVAD decrement in mitral regurgitation (MR) and LVEDD. Outcome measures were pump thrombus or stroke (PT/eCVA); 30-day and total heart failure-related readmissions (HFRAs); and survival free of surgery for LVAD dysfunction. Results: One hundred fourteen patients met criteria. Total malposition magnitude was higher for CS than LTHS (p=0.04). Midline-LV apex distance predicted lateral-plane malposition (p=0.04), while apex-LVOT angle predicted both anterior- (p=0.01) and lateral-plane (p=0.04) malposition. Lateral-plane malposition predicted decreased LVAD FI at three (p=0.03) and six (p=0.01) months. Total malposition magnitude predicted increased 30-day HFRAs (p=0.04), while lateral-plane malposition predicted more overall HFRAs (p=0.01). Malposition was not associated with PT/eCVA, changes in MR or LVEDD, or survival free of surgical revision. Conclusions: Patient anatomy and surgical technique were associated with CF-LVAD IFC malposition. In turn, malposition was associated with increased readmissions and decreased LVAD FI.

Outcomes of systemic anticoagulation with bivalirudin for Impella 5.0

Temporary mechanical circulatory support (tMCS) devices are used for the management of cardiogenic shock. The Impella 5.0 (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 in IMP5. This single center, retrospective study included patients supported on IMP5 with BIV based AC. The efficacy and safety end points were recovery, bridge to left ventricular assist device (LVAD), cardiac transplant (HTX), or death as well as clinically significant bleeding, incidence of Tissue Plasminogen Activator (tPA) use for suspected pump thrombosis, stroke, and device failure. There were 31 patients included, and 26 (84%) received BIV purge solutions. The median duration of IMP5 was 6 (IQR 4–10) days. Most patients were bridged to LVAD (39%, 12); 16% (5) were bridged to HTX, 16% (5) recovered, and 29% (9) died. One patient (3%) suffered from ischemic stroke and 12% (4) patients developed clinically significant bleeding. tPA was administered to 8 (26%) patients. Logistic regression analysis demonstrated that duration of IMP5 was a significant predictor of tPA use (OR 1.28; 95% Confidence Interval 1.04–1.56). There were no cases of pump failure. Our experience highlights the feasibility of utilizing BIV for routine AC use in IMP5.