Faculty Bibliography

Study: The Impella (Abiomed, Danvers, MA) ventricular support system is a family of temporary mechanical circulatory support devices designed to treat patients with cardiogenic shock. These devices include the percutaneously implanted 2.5/CP and the surgically implanted 5.0/LD. Data to assess adverse outcomes and help guide decision-making between Impella CP and 5.0/LD devices is limited. The purpose of this study was to compare the characteristics and clinical outcomes between Impella CP and 5.0/LD at our institution.
Method(s): From December 1, 2014 to October 31, 2019 a total of 117 patients underwent Impella implantation regardless of indication or device type. Of these, 82 patients were supported for greater than 24-hour duration. Baseline patient characteristics and outcomes were reviewed retrospectively. Groups were stratified based on either initial Impella CP or 5.0/LD placement and their clinical outcomes compared.
Result(s): Impella CP was implanted in 56 patients (median age: 60.5 years, male 71.4%) and Impella 5.0/LD (median age: 65.5 years, male 84.6%) were implanted in 26 patients. Regardless of the indication for Impella placement, 24 patients with Impella CP required additional mechanical support and were upgraded to either Impella 5.0/LD or extracorporeal membrane oxygenation (ECMO) (p=0.005). Patients with Impella CP had increased incidence of hemolysis defined as the presence of gross hematuria and elevated lactated dehydrogenase (Table 1). Patients with Impella 5.0/LD were more likely to survive from Impella and survive to discharge. Data from this study suggests that Impella 5.0/LD may have a more favorable device-specific adverse event profile compared to Impella CP

Study: Despite advances in design and hemocompatibility, pump thrombosis remains a significant cause of morbidity for patients implanted with durable left ventricular assist devices (LVAD). Pharmacologic fibrinolysis may be preferred as initial therapy because it obviates a surgical procedure. Yet, it historically has been associated with a significant risk of secondary intracerebral hemorrhage (ICH).
Method(s): We implemented a novel protocol to treat HVAD pump thrombosis and minimize risk of ICH that consisted of the following: initiation of a non-titrating heparin infusion at 500 units/hr; normalization of international normalized ratio (INR) by giving a flat dose of 1,000 units of four-factor prothrombin complex concentration (4F-PCC); and administration of alteplase as a 10 mg bolus followed by 40 mg given over 3 hours.
Result(s): Two patients underwent treatment with the above protocol for presumed HVAD pump thrombosis based on clinical signs of hemolysis and elevations of power on log-file analysis. One patient was 2 months from HVAD implant and the other 13 months. Both patients had subtherapeutic INR in the preceding weeks. Following administration of alteplase, log-file analysis demonstrated immediate resolution of power elevations (Fig. 1). Both patients had a subsequent rise in power requiring repeat alteplase dosing. No bleeding or thrombotic events occurred with treatment. One patient underwent heart transplant a month after treatment and is doing well; the second patient is stable on HVAD support 4 months following alteplase. Combining 4F-PCC to temporarily normalize the INR with repeat dosing of alteplase was effective at resolving HVAD pump thrombosis without bleeding complications and should be investigated further

Introduction: Coronavirus disease 2019 (COVID-19) remains a worldwide pandemic with some patients requiring escalation to venovenous extracorporeal membrane oxygenation (VV-ECMO). Our ECMO Program placed 30 adult COVID-19 patients on VV ECMO within six weeks. This surge required immediate assessment of our program's current structure and resources and rapid execution of an emergency response plan.
Method(s): Additional hardware and disposable supplies were acquired through capital purchases, rental agreements, collaboration with neighboring institutions, and repurposing of existing equipment. All patients were ultimately cohorted to one location. Our Perfusion team implemented a new staffing schedule to increase ECMO coverage. A condensed COVID ECMO course was created to increase the number of ECMO-trained nurses. Existing bedside cannulation carts and an exchange process with Central Supply allowed for multiple cannulations in various locations. A daily report was distributed to ECMO and hospital leadership to promote effective communication and ensure transparency of ECMO capacity.
Result(s): As of August 20th, 27 patients survived to ECMO decannulation and 23 patients survived to hospital discharge. Five patients remain hospitalized. During the surge, we averaged 13 patients on ECMO per day, which was an increase over our baseline of 3.5 patients per day for the six months preceding COVID-19.
Conclusion(s): We conclude that it is possible to safely expand ECMO capacity during a pandemic. This requires proper planning and reallocation of resources as necessary. Our navigation of the surge was aided by our existing program processes and the generosity of neighboring ECMO programs and our industry partners

BACKGROUND:The Impella (Abiomed) ventricular support system is a family of temporary mechanical circulatory support (MCS) devices used to treat patients with cardiogenic shock, acute cardiogenic decompensation, and for high-risk percutaneous or surgical revascularization. These devices include the percutaneously implanted 2.5/cardiac power (CP) and the surgically implanted 5.0/left direct (LD). Despite the beneficial effects and increased usage of these devices, data to assess adverse outcomes and guide clinician decision-making between the Impella CP and 5.0/LD are limited. METHODS:This is a retrospective analysis of 91 consecutive patients who required at least 24 h of Impella support, from January 1, 2015 to December 31, 2019. Groups were stratified based on either initial Impella CP or 5.0/LD placement. Clinical outcomes and in-hospital complications were compared. RESULTS:Impella CP was implanted in 66 patients (mean age: 61 ± 15 years, male 71.2%) and Impella 5.0/LD was implanted in 25 patients (mean age: 62 ± 9 years, male 84.0%). There was greater stability of device position (p = .033), less incidence of hemolysis (p < .001), and less frequent need for additional MCS (p = .001) in patients implanted with the Impella 5.0/LD compared with Impella CP in this study cohort. Patients with Impella 5.0/LD were more likely to survive from Impella and survive to discharge. CONCLUSIONS:This study suggests that for patients who require temporary MCS for more than 24 h, the Impella 5.0/LD may have a more favorable device-specific adverse profile compared with the Impella CP.

Over the past several decades, the operation of choice for end-stage lung disease secondary to severe pulmonary hypertension (PH) has shifted from heart-lung transplantation (HLT) to bilateral lung transplantation (BLT). This change has maintained excellent long-term outcomes and is appropriate for the majority of patients presenting with end-stage disease in need of transplantation. However, a distinct subset of patients with severe PH have an excessive early mortality within 90 days of transplantation. Based on the different causes of this early mortality compared to BLT recipients with other indications, right heart failure and refractory primary graft dysfunction (PGD) appear to play a significant role. It is therefore critical to identify this subset of patient during their evaluation for transplant. This distinction would allow specific patient referral for HLT, which may mitigate those causes of early mortality. Similarly, there is a subgroup of BLT recipients for severe PH that fail to recover right ventricular function, with suboptimal long-term functional status that is independent of early survival. Identification and referral for HLT of these patients may also be important. In this manuscript, we describe our institutional approach and consideration for the risks of early mortality from right heart failure and PGD, as well failure of right ventricular recovery long-term. The described evaluation is used to ascertain those patients with severe PH who may benefit from a HLT over BLT.

BACKGROUND:Increased utilization of hepatitis C virus (HCV)-positive donors has increased transplantation rates. However, high levels of viremia have been documented in recipients of viremic donors. There is a knowledge gap in how transient viremia may impact acute cellular rejections (ACRs). METHODS:In this study, 50 subjects received hearts from either viremic or non-viremic donors. The recipients of viremic donors were classified as nucleic acid amplification testing (NAT)+ group, and the remaining were classified as NAT-. All patients were monitored for viremia levels. Endomyocardial biopsies were performed through 180 days, evaluating the incidence of ACRs. RESULTS:A total of 50 HCV-naive recipients received hearts between 2018 and 2019. A total of 22 patients (44%) who received transplants from viremic donors developed viremia at a mean period of 7.2 ± 0.2 days. At that time, glecaprevir/pibrentasvir was initiated. In the viremia period (<56 days), 14 of 22 NAT+ recipients (64%) had ACR vs 5 of 28 NAT- group (18%) (p = 0.001). Through 180 days, 17 of 22 NAT+ recipients (77%) had a repeat rejection biopsy vs 12 of 28 NAT- recipients (43%) (p = 0.02). NAT+ biopsies demonstrated disparity of ACR distribution: negative, low-grade, and high-grade ACR in 84%, 12%, and 4%, respectively, vs 96%, 3%, and 1%, respectively, in the NAT- group (p = 0.03). The median time to first event was 26 (interquartile range [IQR]: 8-45) in the NAT+ group vs 65 (IQR: 44-84) days in the NAT-. Time to first event risk model revealed that NAT+ recipients had a significantly higher rate of ACR occurrences, adjusting for demographics (p = 0.004). CONCLUSIONS:Transient levels of viremia contributed to higher rates and severity of ACRs. Further investigation into the mechanisms of early immune activation in NAT+ recipients is required.

Worldwide, the majority of heart transplant organs are from donation after brain death. However, the shortage of suitable donors places severe limitations on this route. One option to increase the donor pool is to use organs from donation after circulatory death (DCD). Transplant centers for solid organs have been using DCD organs for years. At this time, 40% of solid organ transplantation in the United Kingdom uses organs from DCD. Use of DCD for solid organ transplants in Canada is also rising. Recently, there has been interest in using DCD organs for heart transplantation. The authors will discuss their experience of 4 heart transplants with organs from DCD donors after normothermic regional perfusion (NRP). The authors' first heart transplant using a DCD organ was in January 2020, and the fourth was in March 2020, just before the coronavirus disease 2019 (COVID-19) pandemic. The authors' protocol using NRP allows adequate evaluation of the donor heart to confidently determine organ acceptance. The co-location of the donor and the recipient in neighboring operating rooms limits ischemic times. Avoidance of an expensive ex vivo organ perfusion machine is an additional benefit for programs that may not have the resources required to purchase and maintain the machine. Some hospitals may not have the resources and space to be able to co-locate both the donor and recipient. Use of cold storage may be an option to transport the procured organ, similar to donation after brain death organs. The authors hope that this technique of NRP in DCD donors can help further increase the donor pool for heart transplantation in the United States.