Current Landscape of Temporary Percutaneous Mechanical Circulatory Support Technology

Mechanical circulatory support devices provide hemodynamic support to patients who present with cardiogenic shock. These devices work using different mechanisms to provide univentricular or biventricular support. There is a growing body of evidence supporting use of these devices as a goal for cardiac recovery or as a bridge to definitive therapy, but definitive, well-powered studies are still needed. Mechanical circulatory support devices are increasingly used using shock team and protocols, which can help clinicians in decision making, balancing operator and institutional experience and expertise. The aim of this article is to review commercially available mechanical circulatory support devices, their profiles and mechanisms of action, and the evidence available regarding their use.

474. Unique Treatment Challenges with Multisystem Inflammatory Syndrome in Children (MIS-C) compared to Kawasaki Disease Shock Syndrome

Background Kawasaki disease (KD) and Multisystem Inflammatory Syndrome in Children (MIS-C) associated with Coronavirus Disease 2019 present similarly with mucocutaneous symptoms and fever. Both syndromes can progress to shock. Successful treatments for MIS-C are largely based on proven KD management. As more patients with MIS-C are treated, protocols are adjusted. Infectious Diseases (ID) specialists are often early consultants in these cases. Understanding differences in how body systems are affected in MIS-C versus KD is essential for management. Figure 1. Cardiac changes among patients with Kawasaki Disease shock syndrome (KDSS) and Muti-system Inflammatory Syndrome (MIS-C) Methods This is a single hospital comparison of 25 cases of MIS-C with mucocutaneous presentation and symptoms of shock and 25 consecutive cases of KD Shock Syndrome (KDSS). Cases were compared for demographics, symptoms, cardiac abnormalities, medical treatments, and cardiac recovery. Results Patients with MIS-C develop symptoms of shock including sustained hypotension and tachycardia at 3 times the rate of patients with KD (45% vs 13%; p< 0.001). On echocardiogram, left ventricular myocardial dysfunction, assessed by ejection fraction, is more commonly noted in cases of MIS-C than KDSS (fig 1). About half of patients with MIS-C show left ventricular myocardial dysfunction initially with normalization by 6 months post-presentation in the majority (96%). Conclusion Cardiac changes and shock events related to KD and MIS-C are thought to be caused by differing inflammatory mediators. By comparing these two syndromes, we can determine ways to manage each optimally. MIS-C often results in left ventricular myocardial dysfunction, which is rarer in KD cases. Fluid resuscitation with multiple fluid boluses followed by inotropes to treat hypotension in cases of in MIS-C puts increased strain on the already weakened myocardium. Early intravenous immunoglobulin (IVIG) administration, even in the presence of mild hypotension, can simultaneously provide the patient with additional fluid and decrease the underlying inflammatory process. This prompt treatment might reduce the need for pressor support while protecting the myocardium from further damage. As early consultants in MIS-C, ID providers should be educated regarding the unique cardiac challenges of MIS-C and avoid delay in IVIG treatment and cardiologist and intensivist consultation. Disclosures All Authors: No reported disclosures

Baseline QRS Duration Associates with Cardiac Recovery in Patients with Continuous-Flow Left Ventricular Assist Device Implantation

BACKGROUND: In chronic heart failure (HF) patients supported with continuous-flow left ventricular assist device (CF-LVAD), we aimed to assess the clinical association of baseline QRS duration (QRSd) with post-LVAD cardiac recovery, and its correlation with pre- to post-LVAD change in left ventricular ejection fraction (LVEF) and left ventricular end-diastolic diameter (LVEDD). METHODS: Chronic HF patients (n=402) undergoing CF-LVAD implantation were prospectively enrolled, at one of the centers comprising the U.T.A.H. (Utah Transplant Affiliated Hospitals) consortium. After excluding patients with acute HF etiologies, hypertrophic or infiltrative cardiomyopathy, and/or inadequate post-LVAD follow-up (<3 months), 315 patients were included in the study. Cardiac recovery was defined as LVEF ≥40% and LVEDD <6 cm within 12 months post-LVAD implantation. Patients fulfilling this condition were termed as responders (R) and results were compared with non-responders (NR). RESULTS: Thirty-five patients (11%) achieved R criteria, and exhibited a 15% shorter QRSd compared to NR (123±37 ms vs 145±36 ms; p<0.001). Univariate analysis identified an association of baseline QRSd with post-LVAD cardiac recovery (OR:0.986, 95% CI:0.976-0.996, p<0.001). In a multivariate logistic regression model, after adjusting for duration of HF (OR:0.990, 95% CI:0.983-0.997, p=0.006) and gender (OR:0.388, 95% CI:0.160-0.943, p=0.037), pre-LVAD QRSd exhibited a significant association with post-LVAD cardiac structural and functional improvement (OR:0.987, 95% CI:0.977-0.998, p=0.027) and the predictive model showed a c-statistic of 0.73 with p<0.001. The correlations for baseline QRSd with pre- to post-LVAD change in LVEF and LVEDD were also investigated in R and NR groups. CONCLUSION: Chronic advanced HF patients with a shorter baseline QRSd exhibit an increased potential for cardiac recovery after LVAD support.

The Role of the VEGF Family in Coronary Heart Disease

The vascular endothelial growth factor (VEGF) family, the regulator of blood and lymphatic vessels, is mostly investigated in the tumor and ophthalmic field. However, the functions it enjoys can also interfere with the development of atherosclerosis (AS) and further diseases like coronary heart disease (CHD). The source, regulating mechanisms including upregulation and downregulation, target cells/tissues, and known functions about VEGF-A, VEGF-B, VEGF-C, and VEGF-D are covered in the review. VEGF-A can regulate angiogenesis, vascular permeability, and inflammation by binding with VEGFR-1 and VEGFR-2. VEGF-B can regulate angiogenesis, redox, and apoptosis by binding with VEGFR-1. VEGF-C can regulate inflammation, lymphangiogenesis, angiogenesis, apoptosis, and fibrogenesis by binding with VEGFR-2 and VEGFR-3. VEGF-D can regulate lymphangiogenesis, angiogenesis, fibrogenesis, and apoptosis by binding with VEGFR-2 and VEGFR-3. These functions present great potential of applying the VEGF family for treating CHD. For instance, angiogenesis can compensate for hypoxia and ischemia by growing novel blood vessels. Lymphangiogenesis can degrade inflammation by providing exits for accumulated inflammatory cytokines. Anti-apoptosis can protect myocardium from impairment after myocardial infarction (MI). Fibrogenesis can promote myocardial fibrosis after MI to benefit cardiac recovery. In addition, all these factors have been confirmed to keep a link with lipid metabolism, the research about which is still in the early stage and exact mechanisms are relatively obscure. Because few reviews have been published about the summarized role of the VEGF family for treating CHD, the aim of this review article is to present an overview of the available evidence supporting it and give hints for further research.

Targeted anti-BCR-ABL+ ALL therapy may benefit the heart

Targeted therapies are currently considered the best cost-benefit anti-cancer treatment. In hematological malignancies, however, relapse rates and non-hematopoietic side effects including cardiotoxicity remain high. We here describe significant heart damage due to advanced acute lymphoblastic leukemia with t(9;22) encoding the bcr-abl oncogene (BCR-ABL+ ALL) in murine xenotransplantation models. Echocardiography reveals severe cardiac dysfunction with impaired left ventricular function and reduced heart and cardiomyocyte dimensions associated with increased apoptosis. This cardiac damage is fully reversible, but cardiac recovery depends on the therapy used to induce ALL remission. Chemotherapy-free therapy with dasatinib and venetoclax (targeting the BCR-ABL oncoprotein and mitochondrial Bcl2, respectively), as well as dexamethasone can fully revert cardiac defects whereas depletion of otherwise identical ALL in a genetic model using HSV-TK cannot. Mechanistically, dexamethasone induces pro-apoptotic BIM expression and apoptosis in ALL cells but enhances pro-survival BCLXL expression in cardiomyocytes and clinical recovery with reversion of cardiac atrophy. These data demonstrate that therapies designed to optimize apoptosis induction in ALL may circumvent cardiac on-target side effects and may even activate cardiac recovery. In the future, combining careful clinical monitoring of cardiotoxicity in leukemic patients with further characterization of organ-specific side effects and signaling pathways activated by malignancy and/or anti-tumor therapies seems reasonable.

Comparison of Experimental Rat Models in Donation After Circulatory Death (DCD): in-situ vs. ex-situ Ischemia

Introduction: Donation after circulatory death (DCD) could substantially improve donor heart availability. However, warm ischemia prior to procurement is of particular concern for cardiac graft quality. We describe a rat model of DCD with in-situ ischemia in order to characterize the physiologic changes during the withdrawal period before graft procurement, to determine effects of cardioplegic graft storage, and to evaluate the post-ischemic cardiac recovery in comparison with an established ex-situ ischemia model.Methods: Following general anesthesia in male, Wistar rats (404 ± 24 g, n = 25), withdrawal of life-sustaining therapy was simulated by diaphragm transection. Hearts underwent no ischemia or 27 min in-situ ischemia and were explanted. Ex situ, hearts were subjected to a cardioplegic flush and 15 min cold storage or not, and 60 min reperfusion. Cardiac recovery was determined and compared to published results of an entirely ex-situ ischemia model (n = 18).Results: In donors, hearts were subjected to hypoxia and hemodynamic changes, as well as increased levels of circulating catecholamines and free fatty acids prior to circulatory arrest. Post-ischemic contractile recovery was significantly lower in the in-situ ischemia model compared to the ex-situ model, and the addition of cardioplegic storage improved developed pressure-heart rate product, but not cardiac output.Conclusion: The in-situ model provides insight into conditions to which the heart is exposed before procurement. Compared to an entirely ex-situ ischemia model, hearts of the in-situ model demonstrated a lower post-ischemic functional recovery, potentially due to systemic changes prior to ischemia, which are partially abrogated by cardioplegic graft storage.