Utilization and Outcomes of Temporary Mechanical Circulatory Support Devices in Cardiogenic Shock

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.

Incremental cost-effectiveness of extracorporeal membranous oxygenation as a bridge to cardiac transplant or left ventricular assist device placement in patients with refractory cardiogenic shock

Objective

Emerging literature has described using venoarterial extracorporeal membranous oxygenation (ECMO) as a bridge to transplant or left ventricular assist device (LVAD) placement. We sought to identify the incremental cost-effectiveness ratio (ICER) of ECMO used as a bridge to cardiac transplant or LVAD.

Methods

Patients with refractory cardiogenic shock who received venoarterial ECMO and were bridged to either cardiac transplant (n = 7) or a HeartMate 3 LVAD (n = 6) placement were included. Markov modeling was used, comparing ECMO bridging with non–ECMO-bridged patients. Cohorts entered the model alive and at every 1-year cycle, were exposed to risk of death, and ran forward for 20 years after transplant or LVAD.

Results

Patients bridged with ECMO to cardiac transplant were stratified as group 1 whereas those bridged with ECMO to LVAD were stratified as group 2. The average ECMO run was 3 days in group 1 versus 11 days in group 2. Among group 1 patients, the ICER was $246,629 but was paired with a longer life expectancy. The ICER of group 2 patients was –$107,088 and was not paired with a longer life expectancy. The average inpatient cost for group 1 was found to be $636,023 versus $769,471 for group 2 patients. The average inpatient costs for patients not bridged to ECMO who received cardiac transplant or LVAD was $538,928 and $325,242, respectively.

Conclusions

Using ECMO to bridge to transplant or LVAD placement is not cost effective. However, patients bridged to transplant are paired with longer life expectancy in contrast to patients bridged to LVAD.

Bridge to transplantation from mechanical circulatory support: a narrative review

Objective

To highlight recent developments in the utilization of mechanical circulatory support (MCS) devices as bridge-to-transplant strategies and to discuss trends in MCS use following the changes to the United Network for Organ Sharing (UNOS) heart allocation system.

Background

MCS devices have played an increasingly important role in the treatment of heart failure patients. Over the past several years, technological advancements have led to new developments in MCS devices and expanding indications for MCS use. In October of 2018, the UNOS heart allocation policy was revised to prioritize higher-urgency patients, including those supported with temporary MCS devices. Since then, changes in trends of MCS utilization have been observed.

Methods

Articles from the PubMed database regarding the use of MCS devices as bridge-to-transplant strategies were reviewed.

Conclusions

Over the past decade, utilization of temporary MCS devices, which include the intra-aortic balloon pump (IABP), percutaneous ventricular assist devices (pVADs), and extracorporeal membrane oxygenation (ECMO), has become increasingly common. Recent advancements in MCS include the development of pVADs that can fully unload the left ventricle (LV) as well as devices designed to provide right-sided support. Technological advancements in durable left ventricular assist devices (LVADs) have also led to improved outcomes both on the device and following heart transplantation. Following the 2018 UNOS heart allocation policy revision, the utilization of temporary MCS in advanced heart failure patients has further increased and the proportion of patients bridged directly from a temporary MCS device has exponentially risen. However, following the start of the COVID-19 pandemic, the trends have reversed, with a decrease in the percentage of patients bridged from a temporary MCS device. As long-term data following the allocation policy revision becomes available, future studies should investigate how trends in MCS use for patients with advanced heart failure continue to evolve.

Evaluation of a Novel Left Ventricular Assist Device for Resuscitation in an Animal Model of Ventricular Fibrillation Cardiac Arrest

We evaluated an independently developed novel percutaneous implantable left ventricular assist device for resuscitation in a pig model of ventricular fibrillation cardiac arrest. The model was established in 10 domestic pigs by blocking the anterior descending coronary artery with a balloon after anesthesia. With ventilator-assisted ventilation, the independently developed percutaneous implantable left ventricular assist device was inserted via the femoral artery to assist circulation. According to whether effective circulatory support was achieved, the pigs were randomly divided into an experimental group and a control group. The experimental group was subjected to insertion of the assist device and received continuous circulatory support. The control group underwent insertion of the assist device; however, it did not start it within 15 minutes. For all animals, if successful rescue was achieved (sinus rhythm restoration within 15 minutes and maintenance for over 5 minutes), circulatory support was stopped, and the arterial blockage was removed. If sinus rhythm was not restored within 15 minutes, electric defibrillation, adrenaline injection, and removal of the arterial blockage were performed, and circulatory support was provided until sinus rhythm recovered. A determination of failed rescue was made when sinus rhythm was not restored after 1 hour. All successfully rescued animals were fed for 1 week. There were no significant differences in baseline data between the groups. All animals underwent successful novel left ventricular assist device implantation through the femoral artery. The rescue rate was significantly higher in the experimental group than in the control group (80% vs. 0%, [Formula: see text]). All successfully rescued animals survived after 1 week of feeding, and no eating or movement abnormalities were observed. We conclude that this independently developed percutaneous implantable left ventricular assist device can be conveniently and rapidly implanted through the femoral artery and can maintain basic circulatory perfusion during resuscitation in an animal model of cardiac arrest.

Contemporary Use of Venoarterial Extracorporeal Membrane Oxygenation: Insights from the Multicenter RESCUE Registry

BACKGROUND

Venoarterial extracorporeal membrane oxygenation (VA-ECMO) is increasingly used as a life-saving therapy for patients with cardiovascular collapse, but identifying patients unlikely to benefit remains a challenge.

METHODS AND RESULTS

We created the RESCUE registry, a retrospective, observational registry of adult patients treated with VA-ECMO between January 2007 and June 2017 at 3 high-volume centers (Columbia University, Duke University, and Washington University) to describe short-term patient outcomes. In 723 patients treated with VA-ECMO, the most common indications for deployment were postcardiotomy shock (31%), cardiomyopathy (including acute heart failure) (26%), and myocardial infarction (17%). Patients frequently suffered in-hospital complications, including acute renal dysfunction (45%), major bleeding (41%), and infection (33%). Only 40% of patients (n = 290) survived to discharge, with a minority receiving durable cardiac support (left ventricular assist device [n = 48] or heart transplantation [n = 7]). Multivariable regression analysis identified risk factors for mortality on ECMO as older age (odds ratio [OR], 1.26; 95% confidence interval [CI], 1.12-1.42) and female sex (OR, 1.44; 95% CI, 1.02-2.02) and risk factors for mortality after decannulation as higher body mass index (OR 1.17; 95% CI, 1.01-1.35) and major bleeding while on ECMO support (OR, 1.92; 95% CI, 1.23-2.99).

CONCLUSIONS

Despite contemporary care at high-volume centers, patients treated with VA-ECMO continue to have significant in-hospital morbidity and mortality. The optimization of outcomes will require refinements in patient selection and improvement of care delivery.

Vasopressors and Inotropes as Predictors of Mortality in Acute Severe Cardiogenic Shock Treated With the Impella Device

BACKGROUND

Vasopressors and inotropes are the primary pharmacologic agents in the management of cardiogenic shock. Increased use of these agents in the setting of cardiogenic shock treated with the Impella is associated with increased mortality. This study evaluates the use of vasopressors and inotropes as predictors of mortality in patients treated with the Impella for acute cardiogenic shock.

METHODS

This retrospective study included 276 patients treated with the Impella 2.5, Impella CP, or Impella 5.0 from March 2011 to January 2020 at a single, tertiary referral center for acute cardiogenic shock.

RESULTS

All-cause in-hospital mortality was 44.6%. Mortality significantly increased with escalating use of vasopressors and inotropes, with the most significant increase in mortality from use of 2 agents to the use of 3 agents (8.1% vs 39.7%, p < 0.001). There was no difference in mortality whether dobutamine or milrinone was used (44.4% vs 35.7%, p = 0.41); there was increased mortality with use of multiple inotropes. Patients treated with only vasopressors had increased mortality compared to those treated with a combination of agents that included 1 inotrope.

CONCLUSIONS

The escalating need for vasopressors and inotropes and particular combinations of these agents are significant predictors of mortality that may help determine whether the Impella or higher level of support is more appropriate to treat acute cardiogenic shock.

Trends, Outcomes, and Predictors of Revascularization in Cardiogenic Shock

Cardiogenic shock (CS) carries high mortality and morbidity. Early revascularization is an important strategy in management of these patients. We sought to determine the outcomes and predictors of revascularization among patients with CS. Patients with CS and acute myocardial infarction were identified using the National Inpatient Sample (NIS) data from January 2002 to December 2014 using the International Classification of Diseases, 9th Revision, Clinical Modification (ICD-9-CM) codes. Subsequently, patients who underwent revascularization were then selected. A total of 118,618 patients with CS were identified. Out of these, about 55,735 (47%) patients underwent revascularization. Mean age of patients who underwent revascularization was lower when compared with patients not who underwent revascularization (66.40 vs 72.24 years, p < 0.01). Patients who underwent revascularization had lower mortality when compared with patients not who underwent revascularization (25.1% vs 52.2%, p < 0.01). Extracorporeal membrane oxygenation and mechanical circulatory support devices were often utilized more in patients who underwent revascularization. Overall, we found modest increased trend of revascularization over our study years with decline in mortality. Female gender, weekend admission, drug abuse, pulmonary hypertension, anemia, renal failure, neurological disorders, malignancy were associated with lower odds of revascularization. In conclusion, in this large nationally represented US population sample of CS patients, we found revascularization rate of about 47% with improvement in overall mortality over our study years.