Aortic thrombosis with visceral malperfusion during circulatory support with a combination of Impella and extracorporeal membrane oxygenation for postcardiotomy cardiogenic shock

Although veno-arterial extracorporeal membrane oxygenation (VA-ECMO) has been used to aid myocardial recovery in patients with postcardiotomy cardiogenic shock (PCCS), it has been associated with adverse effects. The combined use of VA-ECMO and Impella (ECPELLA) for PCCS, however, has been reported to be efficacious with few reports of thromboembolic events. We present a case of aortic thrombosis with visceral malperfusion during ECPELLA management for PCCS. We performed the Bentall procedure, mitral valve repair, tricuspid annuloplasty, and coronary artery bypass graft on a 73-year-old man admitted with congestive heart failure caused by annuloaortic ectasia, along with severe aortic and mitral regurgitation. VA-ECMO and Impella were required, since the cardiopulmonary bypass weaning was difficult. Impella was removed on postoperative day 4. On postoperative days 5 and 6, laboratory data showed worsening renal dysfunction, lactate levels, and acidosis. Contrast-enhanced computed tomography showed thrombosis in the celiac and superior mesenteric arteries. Aortic thrombectomy was performed. Hyperkalemia, caused by a reperfusion injury, resulted in ventricular fibrillation. Continuous hemodiafiltration improved the hyperkalemia. However, irreversible acidosis progressed, and the VA-ECMO flow rate could not be sustained. On postoperative day 7, the patient died. Perioperative use of Impella for PCCS may be effective in improving postoperative cardiac function. When sudden organ failure is observed after surgery, it is necessary to not only keep the exacerbation of cardiogenic shock in mind, but also the possibility of thrombosis.

Anticoagulation practices and complications associated with Impella® support at an advanced cardiac center in the Middle East gulf region

Anticoagulation during Impella® support is a challenge due to its complications and inconsistent practice across the globe. This observational, retrospective chart review included all patients with Impella® support at our advanced cardiac center at a quaternary care hospital in the Middle East gulf region. The study was conducted over six years (2016-2022), a time period during which manufacturer recommendations for purge solution, anticoagulation protocols as well as Impella® place in therapy and utilization were all evolving. We aimed to evaluate the efficacy of different anticoagulation practices and association with complications and outcomes. Forty-one patients underwent Impella® during the study period, including 25 patients with support for more than 12 h, and are the focus of our analysis. Cardiogenic shock (n = 25, 60.9%) was the primary indication for Impella®, followed by facilitating high-risk PCI (n = 15, 36.7%) and left ventricular afterload reduction in patients undergoing veno-arterial extracorporeal membrane oxygenation (n = 1, 2.4%). Our overall Impella® usage evolved over the years from a primary use to facilitate a high-risk PCI to the recent more common use of LV unloading in cardiogenic shock. No patients experienced device malfunction and the incidence of other complications including ischemic stroke and bleeding were comparable to those reported in the literature (12.2% and 24% respectively). The 30-day all-cause mortality of 41 patients was 53.6%. In line with the evolving recommendations and evidence, we observed an underutilization of non-heparin-based purge solutions and inconsistent management of anticoagulation in the setting of both Impella® and VA ECMO which necessitates more education and protocols.

Incidence and severity of thrombocytopenia associated with use of intravascular microaxial ventricular assist devices for treatment of cardiogenic shock

INTRODUCTION

The use of temporary mechanical circulatory support (MCS) for patients with refractory cardiogenic shock has increased over the past decade. Impella devices (intravascular microaxial ventricular assist devices [VADs]) have become common MCS options but reportedly cause thrombocytopenia. Limited published data regarding the incidence or severity of microaxial VAD-associated thrombocytopenia exists.

OBJECTIVES

The goal of this study was to determine the incidence, timing, and severity of thrombocytopenia in a microaxial VAD population.

METHODS

A retrospective multicenter review of electronic medical records identified all patients implanted with microaxial VAD at three US academic teaching hospitals between June 2015 and August 2017. Patients were excluded for short-term procedural microaxial VAD use during percutaneous coronary intervention.

RESULTS

Sixty-four patients underwent microaxial VAD insertion (95% for left-sided support) during the observed time period. Support was in place for a median duration of 5.2 (interquartile range [IQR]: 2.4-10.0) days. Within 7 days postinsertion, 98.5% of patients developed thrombocytopenia (platelet count <150,000/μl) and 81.3% of patients experienced a >50% platelet decrease. Average platelet count nadir was 68,200/μl or 63.9% from baseline occurring on median day 3.8 (IQR: 2.4-5.4). Twenty-four patients (38.1%) were tested for heparin-induced thrombocytopenia by the heparin-dependent antibody (HDA) test. All HDAs were either negative or had serotonin release assay negative confirmation. Postdevice removal, platelet counts returned to baseline or >150,000/μl in 63% of patients by Day 5.

CONCLUSION

Microaxial VAD-associated thrombocytopenia is common. Practitioners should consider this when evaluating supported patients for other causes of thrombocytopenia. Platelet counts return to preimplantation levels within days of device removal.

Evaluation of Thrombocytopenia in Patients Receiving Percutaneous Mechanical Circulatory Support With an Impella Device

Evaluate the time course of thrombocytopenia in patients with Impella devices (Abiomed, Danvers, MA).

Outcome of Patients Supported by Large Impella Systems After Re-implantation Due to Continued or Recurrent Need of Temporary Mechanical Circulatory Support

Despite the growing utilization of a large microaxial pump, i. e., Impella 5.0 or 5.5 (Abiomed Inc., Danvers, MA, USA) (Impella 5+) for patients with cardiogenic shock (CS), adverse events including the necessity of re-implantation have not been well discussed. In all 67 patients, in-hospital mortality was 52.2% (n = 35). Explantation of Impella 5+ was performed in 39 patients (58.2%), 22 of whom (32.8%) recovered under Impella 5+, and ten further patients (14.9%) survived after a successful transition to permanent mechanical circulatory support. Embolic events were considerable complications in each access. They occurred in the right arm after the removal of Impella 5+ via a subclavian artery (SA) (n = 3, 9.1%) or in the form of leg ischemia in patients with Impella 5+ via femoral artery (FA) (n = 2, 33.3%). Re-implantation was necessary for 10 patients (14.9%) due to 1) recurrent CS (n = 3), 2) pump thrombosis (n = 5), or 3) pump dislocation (n = 2), all of which were successfully performed via the same access route. In univariate analysis, FA access was a significant risk factor for Impella dysfunction compared to SA access (FA vs. SA, 42.9% vs. 9.8%, p < 0.05, odds ratio 6.88). No statistical difference of overall mortality was observed in patients with Impella 5+ re-implantation (n = 10) compared to patients with primary Impella 5+ support (n = 57) (80.0% (n = 8/10) vs. 47.4% (n = 27/57), p = 0.09). Our results suggested the acceptable clinical outcome of Impella 5+ despite a 15% re-implantation rate. Our observational data may merit further analysis of anticoagulation strategies, including risk stratification for embolic events.

Optimizing anticoagulation for patients receiving Impella support

Anticoagulation of patients treated with the Impella percutaneous mechanical circulatory support (MCS) devices is complex and lacks consistency across centers, potentially increasing the risk of complications. In order to optimize safety and efficacy, an expert committee synthesized all available evidence evaluating anticoagulation for patients receiving Impella support in order to provide consensus recommendations for the management of anticoagulation with these devices. The evidence synthesis led to the creation of 42 recommendations to improve anticoagulation management related to the use of the Impella devices. Recommendations address purge solution management, intravenous anticoagulation, monitoring, evaluation and management of heparin-induced thrombocytopenia (HIT), and management during combination MCS support. The use of a heparinized, dextrose-containing purge solution is critical for optimal device function, and a bicarbonate-based purge solution may be an alternative in certain situations. Likewise, intravenous (ie, systemic) anticoagulation with heparin is often necessary, although evidence supporting the optimal assay and target range for monitoring the level of anticoagulation is generally lacking. Patients treated with an Impella MCS device may develop HIT, which is more difficult to evaluate and treat in this setting. Lastly, the use of Impella with extracorporeal membrane oxygenation or for biventricular support creates additional anticoagulation challenges.

Management of Anticoagulation with Impella® Percutaneous Ventricular Assist Devices and Review of New Literature

Cardiogenic shock is a life-threatening condition that may occur secondary to a variety of cardiac conditions, and may require temporary support with percutaneous ventricular devices like the Impella®. Anticoagulation in patients with Impella® devices can often be complicated due to unpredictable purge flow rates, pre-existing coagulopathy, or heparin allergies. The purpose of this article is to discuss the various options for anticoagulation in the setting of Impella®. The article will also describe recent updates (2014-current) in literature surrounding anticoagulation therapy for Impella® devices. At total of 228 articles were initially obtained through the PubMed search, with inclusion of 6 articles. A total of 51 patients had data in the six studies that were included in the review. Heparin for anticoagulation in the purge solution, at two different dextrose concentrations (5% and 20%), was associated with similar therapeutic activated partial thromboplastin time rates, thrombotic and bleeding events. One case series described the use of argatroban in the purge solution for anticoagulation in two patients with suspected heparin-induced thrombocytopenia, without bleeding or thrombotic complications. Pump thrombosis was not reported in any of the six studies. Anticoagulation in the setting of mechanical circulatory support devices is a challenging aspect of critical care. Institutions should have set protocols that clearly define the options for anticoagulation. Future studies that look at longer durations of support and possible operation of the Impella® device with a heparin-free purge solution are needed.