Minimally Invasive Direct Aortic Implantation of Impella 5.5 As Bridge to Transplant: A Case Report.

The use of temporary mechanical circulatory support in cardiogenic shock (CS) is increasing. The Impella (Abiomed) is a percutaneous, microaxial ventricular assist device approved for short-term use in CS that can be implanted peripherally. Direct aortic placement is an alternative commonly performed when the sternum is open, for example, in post-cardiotomy shock or when the peripheral vasculature is of insufficient size or quality for implantation. Herein, we describe direct aortic implantation of the Impella 5.5 via right mini-thoracotomy for a patient in CS secondary to decompensated heart failure as a bridge to candidacy and, ultimately, transplantation.

Heart Transplant and Donors After Circulatory Death: A Clinical-Preclinical Systematic Review.

INTRODUCTION: Heart transplantation is the treatment of choice for end-stage heart failure. There is a mismatch between the number of donor hearts available and the number of patients awaiting transplantation. Expanding the donor pool is critically important. The use of hearts donated following circulatory death is one approach to increasing the number of available donor hearts. MATERIALS AND METHODS: A systematic review was performed according to the Preferred Reporting Items for Systematic reviews and Meta-Analyses (PRISMA) guidelines utilizing Pubmed/MEDLINE and Embase. Articles including adult human studies and preclinical animal studies of heart transplantation following donation after circulatory death were included. Studies of pediatric populations or including organs other than heart were excluded. RESULTS: Clinical experience and preclinical studies are reviewed. Clinical experience with direct procurement, normothermic regional perfusion, and machine perfusion are included. Preclinical studies addressing organ function assessment and enhancement of performance of marginal organs through preischemic, procurement, preservation, and reperfusion maneuvers are included. Articles addressing the ethical considerations of thoracic transplantation following circulatory death are also reviewed. CONCLUSIONS: Heart transplantation utilizing organs procured following circulatory death is a promising method to increase the donor pool and offer life-saving transplantation to patients on the waitlist living with end-stage heart failure. There is robust ongoing preclinical and clinical research to optimize this technique and improve organ yield. There are also ongoing ethical considerations that must be addressed by consensus before wide adoption of this approach.

Extracorporeal life support as a bridge to lung transplantation: Where are we now?

The number of lung transplant procedures performed internationally is increasing but the donor organ pool is insufficient to meet demand and waiting list mortality is unacceptably high. As survival rates for patients with acute respiratory distress syndrome managed on extracorporeal life support (ECLS) have steadily improved, a potential role for ECLS to support critically ill patients awaiting a donor organ match has emerged. We explore the rapidly evolving landscape of ECLS as a bridge to lung transplantation with review of the patient selection criteria, predictors of survival, modes of pre and peri-transplant support, and the importance of a holistic multidisciplinary approach to care. Finally, we consider innovations that are envisaged to increase the accessibility, safety, and effectiveness of ECLS delivery for future lung transplant candidates.

Multi-Level Lower Extremity Arterial Revascularization Via Retrograde Pedal Access Under Local Anesthesia in a Patient With Severe Cardiopulmonary Comorbidities: A Case Report.

BACKGROUND: Chronic limb-threatening ischemia is a severe form of peripheral artery disease that leads to high rates of amputation and mortality if left untreated. Bypass surgery and antegrade endovascular revascularization through femoral artery access from either side are accepted as conventional treatment modalities for critical limb ischemia. The retrograde pedal access revascularization is an alternative treatment modality useful in specific clinical scenarios; however, these indications have not been well described in literature. This case report highlights the use of retrograde pedal access approach as primary treatment modality in a patient with an extensive comorbidities precluding general anesthesia nor supine positioning. CASE PRESENTATION: The patient is a 60-year-old female with multiple severe cardiopulmonary comorbidities presenting with dry gangrene of the right great toe. Her comorbidities and inability to tolerate supine positioning precluded her from receiving open surgery, general anesthesia or monitored sedation, or percutaneous femoral access. Rather, the patient underwent ankle block and retrograde endovascular revascularization via dorsalis pedis artery access without post-operative complications. DISCUSSION: The prevalence of comorbidities related to peripheral artery disease is increasing and with it the number of patients who are not optimal candidates for conventional treatment methods for critical limb ischemia. The retrograde pedal access revascularization as initial treatment modality offers these patients an alternative limb salvaging treatment option.

Ischemia-reperfusion Injury in the Transplanted Lung: A Literature Review.

Lung ischemia-reperfusion injury (LIRI) and primary graft dysfunction are leading causes of morbidity and mortality among lung transplant recipients. Although extensive research endeavors have been undertaken, few preventative and therapeutic treatments have emerged for clinical use. Novel strategies are still needed to improve outcomes after lung transplantation. In this review, we discuss the underlying mechanisms of transplanted LIRI, potential modifiable targets, current practices, and areas of ongoing investigation to reduce LIRI and primary graft dysfunction in lung transplant recipients.

Postoperative small bowel obstruction secondary to single malformed staple following laparoscopic total abdominal colectomy.

Surgical staplers are ubiquitous in gastrointestinal surgery, especially laparoscopy. Intraperitoneal staples are designed to be inert and are generally regarded as benign; however, complications from primarily malformed staples can rarely occur. Here, we present a case of early mechanical postoperative small bowel obstruction due to a surgical staple following laparoscopic total abdominal colectomy and end ileostomy creation performed for medically refractory ulcerative colitis. Management consisted of diagnostic laparoscopy and careful extraction of a malformed surgical staple tethering a loop of small bowel to the rectal stump. Eight similar cases following gastrointestinal surgery have been identified in the literature, all occurring in the first 2 weeks following laparoscopic appendectomy. To our knowledge, this is the first case described following laparoscopic total abdominal colectomy, with high-grade small bowel obstruction at the level of the rectal stump staple line.

Small bowel necrosis and perforation due to sodium polystyrene sulfonate in the setting of graft versus host disease and fulminant Clostridium difficile infection.

Gastrointestinal injury is a common adverse event associated with use of sodium polystyrene sulfonate (SPS), tradename Kayexalate. Risk factors for SPS-mediated gastrointestinal necrosis include chronic kidney disease, solid organ transplant recipiency and recent surgery. This report presents a patient with past medical history significant for acute myeloid leukemia (AML) complicated by graft versus host disease (GvHD) and Clostridium difficile colitis who initially presented with small bowel obstruction. She was taken to the operating room and her small bowel pathology was significant for transmural necrosis with SPS crystals in the granulation tissue, despite last receiving SPS over a year ago. Previous mucosal damage should be considered as a risk factor for SPS-mediated injury and the effects of this medication may occur longer than previously thought.

Heterotopic Porcine Cardiac Xenotransplantation in the Intra-Abdominal Position in a Non-Human Primate Model.

Heterotopic cardiac transplantation in the intra-abdominal position in a large animal model has been essential in the progression of the field of cardiac transplantation. Our group has over 10 years of experience in cardiac xenotransplantation with pig to baboon models, the longest xenograft of which survived over 900 days, with rejection only after reducing immunosuppression. This article aims to clarify our approach to this model in order to allow others to share success in long-term survival. Here, we demonstrate the approach to implantation of a cardiac graft into the intra-abdominal position in a baboon recipient for the study of transplantation and briefly highlight our model's ability to provide insight into not only xenotransplantation but across disciplines. We include details that have provided us with consistent success in this model; performance of the anastomoses, de-airing of the graft, implantation of a long-term telemetry device for invasive graft monitoring, and ideal geometric positioning of the heart and telemetry device in the limited space of the recipient abdomen. We additionally detail surveillance techniques to assess long-term graft function.

Less Invasive Approach to Left Ventricular Assist Device Implantation May Improve Survival in High-Risk Patients.

OBJECTIVE: Despite improvement in outcomes after left ventricular assist device (LVAD) implantation over the past 2 decades, high-risk recipients continue to have a prohibitive rate of morbidity and mortality. We hypothesized that a less invasive approach to LVAD implantation would be associated with improved survival compared to a conventional approach in this high-risk cohort. METHODS: All consecutive LVAD recipients (2013 to 2017) that underwent centrifugal LVAD implantation were retrospectively reviewed. Patients were classified as high-risk if INTERMACS 1 or required temporary VAD/venoarterial extracorporeal membrane oxygenation prior to durable VAD implantation. Patients were stratified into 3 groups: left thoracotomy with hemi-sternotomy (LTHS) high-risk, conventional sternotomy (CS) high-risk, and non-high-risk. The primary outcome was 1-year survival. RESULTS: A total of 57 patients (LTHS high-risk: 11, CS high-risk: 12, non-high-risk: 34) were identified. Preoperative right ventricular failure scores, HeartMate-II mortality scores, and end-organ dysfunction were similar between the 2 high-risk groups. While operative time was similar between the 3 groups, cardiopulmonary bypass time was significantly shorter in the LTHS high-risk group compared to other groups. There was a trend toward decreased intensive care unit length of stay and ventilator time in LTHS high-risk compared to CS high-risk patients. Moreover, between these 2 groups, there was a significant decrease in temporary right VAD support (50% vs 0%, P = 0.014), and 1-year survival was significantly higher in the LTHS group (42% vs 91%, P = 0.025). CONCLUSIONS: Less invasive LVAD implantation appears to be associated with improved survival compared to conventional LVAD implantation in high-risk patients.

Early tracheostomy after initiation of venovenous extracorporeal membrane oxygenation is associated with decreased duration of extracorporeal membrane oxygenation support.

Timing of tracheostomy placement for patients with respiratory failure requiring venovenous extracorporeal membrane oxygenation support is variable and continues to depend on surgeon preference. We retrospectively reviewed all consecutive adult patients supported with peripheral venovenous extracorporeal membrane oxygenation for acute respiratory distress syndrome at a single institution with the hypothesis that early tracheostomy (within 7 days of extracorporeal membrane oxygenation initiation) decreases the duration of extracorporeal membrane oxygenation support. The primary endpoint was duration of extracorporeal membrane oxygenation support. Secondary endpoints included mortality, overall and intensive care unit length of stay, duration of mechanical ventilation, and time from extracorporeal membrane oxygenation initiation to liberation from ventilator, intensive care unit discharge, and hospital discharge. Overall and extracorporeal membrane oxygenation-associated hospital costs were compared. A total of 50 patients were identified for inclusion (early n = 21; late n = 29). Baseline characteristics including indices of disease severity were similar between groups. Duration of extracorporeal membrane oxygenation support was significantly shorter in the early tracheostomy group (12 vs. 21 days; p = 0.005). Median extracorporeal membrane oxygenation-related costs were significantly decreased in the early tracheostomy group ($3,624 vs. $5,603, p = 0.03). Early tracheostomy placement is associated with decreased time on extracorporeal membrane oxygenation support and reduced extracorporeal membrane oxygenation-related costs in this cohort. Validation in a prospective cohort or a clinical trial is indicated.

High-efficiency, high-flux in-line hemofiltration using a high blood flow extracorporeal circuit.

The ability of current renal replacement therapy modalities to achieve rapid solute removal is limited by membrane surface area and blood flow rate. Extracorporeal membrane oxygenation offers high blood flow and hemodynamic support that may be harnessed to overcome limitations in traditional renal replacement therapy. Using an extracorporeal membrane oxygenation circuit, we describe a high blood flow, high-efficiency hemofiltration technique using in-line hemofilters (hemoconcentrators) and standard replacement fluid to enhance solute clearance. Using this approach and a total of 5 L of replacement volume per treatment, creatinine (Cr) clearances of 8.3 L/hour and 11.2 L/hour using one and two hemoconcentrators, respectively, were achieved. With use of a high blood flow rate of up to 5 L/min, this hemofiltration technique can potentially offer clearance of 30 times that of continuous renal replacement therapy and of 6 times that of hemodialysis which may expand the ability to remove substances traditionally not considered removable via existing extracorporeal therapies.

Early Experience With Preclinical Perioperative Cardiac Xenograft Dysfunction in a Single Program.

BACKGROUND: Perioperative cardiac xenograft dysfunction (PCXD) was described by McGregor and colleagues as a major barrier to the translation of heterotopic cardiac xenotransplantation into the orthotopic position. It is characterized by graft dysfunction in the absence of rejection within 24 to 48 hours of transplantation. We describe our experience with PCXD at a single program. METHODS: Orthotopic transplantation of genetically engineered pig hearts was performed in 6 healthy baboons. The immunosuppression regimen included induction by anti-CD20 monoclonal antibodies (mAb), thymoglobulin, cobra venom factor, and anti-CD40 mAb, and maintenance with anti-CD40 mAb, mycophenolate mofetil, and tapering doses of steroids. Telemetry was used to assess graft function. Extracorporeal membrane oxygenation was used to support 1 recipient. A full human clinical transplantation team was involved in these experiments and the procedure was performed by skilled transplantation surgeons. RESULTS: A maximal survival of 40 hours was achieved in these experiments. The surgical procedures were uneventful, and all hearts were weaned from cardiopulmonary bypass without issue. Support with inotropes and vasopressors was generally required after separation from cardiopulmonary bypass. The cardiac xenografts performed well immediately, but within the first several hours they required increasing support and ultimately resulted in arrest despite maximal interventions. All hearts were explanted immediately; histology showed no signs of rejection. CONCLUSIONS: Despite excellent surgical technique, uneventful weaning from cardiopulmonary bypass, and adequate initial function, orthotopic cardiac xenografts slowly fail within 24 to 48 hours without evidence of rejection. Modification of preservation techniques and minimizing donor organ ischemic time may be able to ameliorate PCXD.

Early Decompressive Laparotomy for Intra-Abdominal Hypertension Following Initiation of Venovenous Extracorporeal Membrane Oxygenation.

Patients supported with venovenous extracorporeal membrane oxygenation are at risk for intra-abdominal hypertension and abdominal compartment syndrome. Flow through the return cannula may be compromised in these patients, resulting in inadequate support and end-organ malperfusion. Early decompressive laparotomy can mitigate these complications and potentially improve outcomes. Here we review a series of nine patients undergoing early decompressive laparotomy for abdominal compartment syndrome at a single institution and propose an algorithmic approach to the management of these patients.

Predictors of Recovery in Patients Supported With Venoarterial Extracorporeal Membrane Oxygenation for Acute Massive Pulmonary Embolism.

BACKGROUND: Venoarterial extracorporeal membrane oxygenation (VA-ECMO) has emerged as a promising initial support strategy for acute massive pulmonary embolism. However, it remains unclear which patients will ultimately require surgical pulmonary embolectomy (SPE) vs anticoagulation alone. METHODS: All consecutive patients (2015-2018) with confirmed massive PE, placed on VA-ECMO utilizing a protocolized approach, were reviewed. Per protocol, patients were supported for 3 to 5 days before reevaluation of right ventricular (RV) function via echocardiography. If RV function recovered, VA-ECMO was discontinued with no further intervention (no-SPE group). In patients with persistent RV dysfunction, SPE was performed. RESULTS: Forty-five patients were identified, and 41 patients were treated per protocol. Seventy-three percent responded to anticoagulation alone, and 27% required SPE. Factors associated with SPE rather than decannulation with anticoagulation alone included prolonged shortness of breath, elevated N-terminal prohormone of brain natriuretic peptide, enlarged pulmonary artery diameter, and history of venous thromboembolism. A predictive algorithm was developed with a negative predictive value of 97% and a specificity of 97% for a low-risk score, and a positive predictive value of 100% and sensitivity of 67% for a high-risk score. Overall, 90-day survival was 97% in the no-SPE group and 100% in the SPE group. CONCLUSIONS: In this cohort, greater than 70% of patients who presented with massive PE and supported with VA-ECMO ultimately recovered with anticoagulation alone. Specific risk factors, likely related to thrombus chronicity, may be associated with lack of RV recovery, and can be utilized for consideration of early surgical intervention to minimize VA-ECMO duration.