End-stage Cardiomyopathy Research Articles

Prevalence and clinical significance of left ventricular thrombus discovered by pathological examination in explanted hearts of patients with end-stage cardiomyopathy

Abstract Objective We sought to determine the prevalence of anatomic LV thrombus detected by pathological examination of explanted hearts in patients with end-stage cardiomyopathy (CM) who have undergone heart transplantation, and to examine the relationship between anatomic LV thrombus missed by cardiac imaging and thromboembolic events. Methods and results A total of consecutive 148 explanted hearts from patients (44 years; 80% were men) undergoing heart transplantation were examined. The most common etiology of end-stage heart failure was dilated CM (53%). Of 148 explanted hearts, LV thrombus was present in 19 patients/hearts (13%). Excluding patients with ischemic CM (n=7), LV thrombus was present in 8 DCMs (9%), 1 genetic associated with LV noncompaction (100%), 2 hypertrophic CM (25%), and 1 arrhythmogenic CM (14%). None of patients with cardiac sarcoidosis (n=5) had LV thrombus. Of these patients, 11 (58%) received anticoagulants with favorable numbers of time in therapeutic range. No patient in the cohort had history of thromboembolic event before heart transplantation. Only 11 patients (26 %) with pathological evidence of LV thrombus had LV thrombus detected by previous echocardiograms (median time difference from echocardiogram to heart transplantation = 170 days). Six of 19 patients with anatomic LV thrombus had undergone cardiac MRI; LV thrombus had been detected in 2 patients (33%). The most common site of missed LV thrombus was LV cavity (where thrombi did not attach to any particular LV endocardial surface) followed by LV apex (Figure). Conclusion The prevalence of LV thrombus found by pathological examination in end-stage heart diseases was 13 % despite anticoagulation in most patients. However, the presence of these thrombi did not cause any serious thromboembolic events. Anatomic LV thrombi were missed by echocardiography/cardiac MRI in approximately 70% of patients. Genetic associated LV noncompaction and HCM were the most 2 prevalent CMs with anatomic thrombi, while none of patients with cardiac sarcoidosis had evidence of LV thrombus. Further study in thromboembolic milieu involving endocardial surface in specific type of CM may be needed.

The myocardium of human dilated nonischemic cardiomyopathy harbors unique tissue-resident lymphocyte subsets

Abstract Purpose The etiology of dilated nonischemic cardiomyopathy (NICM) is often unclear, but thought to be multifactorial, involving an interplay between genetic factors and direct myocardial damage caused by infection, autoimmunity, or toxins. Tissue-resident lymphocytes are non-circulating immune cells which are retained within various tissues and play integral roles in maintaining homeostasis, responding to infection, regulating inflammation, and mediating tissue repair. Despite their likely involvement in various cardiac pathologies, the presence of tissue-resident lymphocytes in the human heart has not yet been well-characterized, neither in health nor in disease. Methods Human left ventricular tissue and paired peripheral blood samples were obtained from six adult organ donors with normal heart function who died of noncardiac causes and from the explants of six adult patients with end-stage nonischemic cardiomyopathy. Heart tissue was processed using mechanical and enzymatic digestion. Mononuclear cells were isolated from both heart and paired blood by density centrifugation. Isolated mononuclear cells were surface stained with an antibody cocktail and interrogated using multidimensional flow cytometry. Results The adult human heart contains a diverse immune cell population (Fig 1A). Both healthy and NICM cardiac lymphocytes express distinct phenotypic profiles which resemble those of resident lymphocytes found across various tissues, distinct from those isolated from paired blood. Frequencies of effector memory T (Tem) cells (CD45RA- CCR7-) were higher in heart than in blood among both CD4+ and CD8+ T-cells. In heart compared to blood, significantly more Tem expressed CD69, a canonical marker of tissue-resident memory T (Trm) cells (Fig 1B). Cardiac Trm, especially CD8+ Trm, expressed classical Trm signature markers including integrins CD103 (epithelial binding) and CD49a (collagen binding). NICM Trm expressed more CD49a than healthy heart Trm (Fig 1C). NK-cells also demonstrated higher CD69 expression (trNK) in heart than in blood, with associated expression of CD103, CD49a, and CXCR6 (Fig 1D). Compared to healthy hearts, NICM trNK were predominantly CD56bright/CD16- (Fig 1E and 1F) and expressed less CD57 (Fig 1D), overall indicating a less mature state with lower cytotoxic potential. Confocal imaging of cardiac tissue revealed CD69-expressing tissue-resident lymphocytes within the cardiac interstitium. Conclusions The adult human heart contains diverse populations of lymphocytes which express canonical markers of tissue residency, similar to lymphocytes resident in other tissues. Compared to healthy hearts, NICM hearts have more CD49a+ Trm, perhaps related to greater fibrosis, and also harbor a distinct subset of immature tissue-resident NK cells which may shed light on pathophysiology. Future work is focused on better exploring the functional phenotypes of these resident cells and better localizing them within the myocardium.FA - Figure 1

Prolonged ventricular activation time as a novel biomarker identifying burn-out phase of hypertrophic cardiomyopathy

Abstract Background Patients with hypertrophic cardiomyopathy (HCM) classically have preserved systolic function and decreased left ventricular end-diastolic volume. However, in a small sub-population, patients paradoxically develop systolic dysfunction, left ventricular dilatation, and ventricular wall thinning, which is known as end-stage hypertrophic cardiomyopathy or "burned-out cardiomyopathy’. Although an electrocardiogram (ECG) is a pivotal tool in HCM, its role in the detection of burned-out HCM has not been investigated. Purpose We assessed the ventricular activation time (VAT), an ECG marker of the duration of ventricular depolarization, as a predictive tool in the detection of the HCM burn-out phase. Methods We prospectively studied consecutive patients diagnosed with HCM via echocardiography at our medical center between 2017 and 2022. The ECG, along with echocardiography, was performed on the same day as the diagnosis. VAT was measured in milliseconds between the onset of the QRS complex to the peak or R wave on the V5 and V6 precordial ECG lead. HCM burn-out phase was supported when the left ventricular ejection fraction (LVEF) was below 50%, measured with echocardiography. Statistical analysis was performed using the SPSS software. Results Forty-five patients with HCM were studied, and their mean age was 51, while 78% (35/45) were male. Echocardiography data upon diagnosis revealed a mean maximum wall thickness of 19 (±3mm) and a mean left ventricular ejection fraction of 65% (±5%). Left ventricular outflow obstruction was present in 31% (14/45). During the study, 24% (11/45) presented atrial fibrillation, 44% (20/45) had an ICD implantation, and 22% (10/45) progressed to the burn-out phase of HCM. HCM patients who presented atrial fibrillation (63±31 vs. 46±14msec, p=0.018) or burn-out phase (65±32 vs. 46±13msec, p=0,009) had a significantly higher VAT than those subsets without. Notably, there was a significant positive relationship between VAT a burn-out phenotype (r=0,385, p=0.009). HCM patients with greater VAT also had a significantly higher risk of presenting a larger left atrial diameter (r=0,295, p=0.048), an increased left ventricular end-diastolic diameter (r=0.306, p=0.041), and a trend of presenting a lower LVEF (r=-0,262, p=0.082). Finally, we revealed a positive relationship between VAT and atrial fibrillation incidence (r=0,352, p=0.018). Conclusion Prolongation of VAT predicts the incidence of burn-out stage in patients with HCM and atrial fibrillation. Therefore, it seems to be a promising, inexpensive ECG marker for HCM progression and severity. Our findings emphasize the pivotal role of the ECG as a useful and inexpensive tool in the diagnostic follow-up of HCM.

Revived Role of Pulmonary Artery Band in Management of Heart Failure in Pediatric Dilated Cardiomyopathy.

Lack of appropriate durable Ventricular Assist Devices (VADs) that can be managed at home for very young children, and long wait times for transplant have led to search for alternate easily reproducible therapies. In the past decade or more, pulmonary artery banding (PAB), as a new indication of an old technology, has been gradually carried out worldwide as an alternative to mechanical circulatory support in children with end-stage left ventricular dilated cardiomyopathy (DCM) complicated with heart failure(HF), and has achieved encouraging early and mid-term outcomes. Technically, PAB is simple, safe, and effective. This is a promising therapeutic strategy, especially in developing countries where heart transplantation is difficult to implement. As a transition before transplantation, and even a potential treatment, PAB brings more options and hope for children with heart failure who are waiting for transplantation and are refractory to drug therapy. This article reviews the past and current situation, the mechanism, the surgical timing, and application prospect of PAB in the treatment of DCM complicated with heart failure.

Influencing and prognostic factors of end-stage hypertrophic cardiomyopathy.

End-stage hypertrophic cardiomyopathy (ES-HCM) is a disease with severe complications and a poor prognosis. This study aimed to explore the influencing and prognostic factors of ES-HCM. A total of 1282 patients with HCM who were hospitalized for the first time at Fujian Medical University Union Hospital between 1 January 2013 and 30 September 2021 were recorded. The patients with HCM and left ventricular ejection fraction (LVEF)<50% were defined as having ES-HCM, and a control group (LVEF≥50%) was generated from the collected medical records of HCM. The patients were matched in a ratio of 4:1 based on age and sex. Logistic regression analysis was used to determine the influencing factors of ES-HCM. Kaplan-Meier survival analysis was performed to analyse the clinical outcomes of ES-HCM patients. A total of 250 inpatients with HCM were enrolled in the study; 50 patients had ES-HCM, and 200 had HCM with LVEF≥50%. The mean age of the patients at enrolment was 62.5±10.3years, and 215 patients (215/250, 86.0%) were male. The median follow-up time of the patients was 2.8 (1.4-5.4) years. The incidence of all-cause death and cardiovascular death in patients with ES-HCM was higher than those in patients with HCM and LVEF≥50% (22/50 [44.0%] vs. 13/200 [6.5%]; 12/50 [24.0%] vs. 4/200 [2.0%], all P<0.001). Multivariate logistic regression analysis showed that the influencing factors associated with ES-HCM included age at first symptom onset (odds ratio [OR]=0.95, 95% CI [0.90, 1.00], P=0.042), New York Heart Association (NYHA) class (OR=7.73, 95% CI [2.93, 20.41], P<0.001), heart rate (OR=1.07, 95% CI [1.02, 1.12], P=0.003), QRS duration (OR=1.03, 95% CI [1.00, 1.05], P=0.020), left ventricular end-diastolic diameter (LVEDD) (OR=1.15, 95% CI [1.04, 1.28], P=0.006), left atrial anteroposterior diameter (LAD) (OR=1.13, 95% CI [1.03, 1.24], P=0.012), and maximum left ventricular wall thickness (MLVWT) (OR=0.80, 95% CI [0.68, 0.93], P=0.005). Among the 50 patients with ES-HCM, NYHA class (P<0.001) and heart rate (P=0.017) were each associated with a higher likelihood and earlier occurrence of heart transplantation or all-cause mortality in univariate analyses. The influencing factors for ES-HCM included the age at first symptom onset, NYHA class, heart rate, QRS duration, LVEDD, LAD, and MLVWT. Both NYHA class and heart rate were related to the prognosis of ES-HCM.

Somatostatin receptors in fibrotic myocardium.

A patient with a neuroendocrine tumor and history of coronary artery disease underwent PET with 68Ga-DOTATATE PET tracer for tumor visualization. Analysis of the scan showed uptake of 68Ga-DOTATATE in the left ventricle corresponding to previous myocardial infarct. 68Ga-DOTATATE binds by somatostatin receptors (SSTR) and it has been proposed that it may be useful for the detection of cardiac inflammatory lesions. We aimed to test whether SSTR could be upregulated in cardiac fibrotic scar. We analyzed SSTR in cardiac samples from patients with end-stage ischemic cardiomyopathy (ICM, n = 8) and control hearts (n = 5). In mature ICM tissue, SSTR1 and SSTR2 expression was unchanged and SSTR5 expression was significantly decreased in ICM samples vs. control. Immunohistochemistry showed increased SSTR1 and SSTR2 in ICM. Areas with SSTR1 or SSTR2 staining were often adjacent to fibrotic areas. The majority of SSTR1 and SSTR2 staining localized in cardiomyocytes in fibrotic scar-rich areas where CD68 macrophage staining was not present. SSTR are occasionally upregulated in cardiac fibrotic areas. When using 68Ga-DOTATATE PET tracer to detect cardiac sarcoidosis or atherosclerotic plaque, the possibility of tracer uptake in fibrotic areas should be considered.

SPTLC3 Is Essential for Complex I Activity and Contributes to Ischemic Cardiomyopathy.

Dysregulated metabolism of bioactive sphingolipids, including ceramides and sphingosine-1-phosphate, has been implicated in cardiovascular disease, although the specific species, disease contexts, and cellular roles are not completely understood. Sphingolipids are produced by the serine palmitoyltransferase enzyme, canonically composed of 2 subunits, SPTLC1 (serine palmitoyltransferase long chain base subunit 1) and SPTLC2 (serine palmitoyltransferase long chain base subunit 2). Noncanonical sphingolipids are produced by a more recently described subunit, SPTLC3 (serine palmitoyltransferase long chain base subunit 3). The noncanonical (d16) and canonical (d18) sphingolipidome profiles in cardiac tissues of patients with end-stage ischemic cardiomyopathy and in mice with ischemic cardiomyopathy were analyzed by targeted lipidomics. Regulation of SPTLC3 by HIF1α under ischemic conditions was determined with chromatin immunoprecipitation. Transcriptomics, lipidomics, metabolomics, echocardiography, mitochondrial electron transport chain, mitochondrial membrane fluidity, and mitochondrial membrane potential were assessed in the cSPTLC3KO transgenic mice we generated. Furthermore, morphological and functional studies were performed on cSPTLC3KO mice subjected to permanent nonreperfused myocardial infarction. Herein, we report that SPTLC3 is induced in both human and mouse models of ischemic cardiomyopathy and leads to production of atypical sphingolipids bearing 16-carbon sphingoid bases, resulting in broad changes in cell sphingolipid composition. This induction is in part attributable to transcriptional regulation by HIF1α under ischemic conditions. Furthermore, cardiomyocyte-specific depletion of SPTLC3 in mice attenuates oxidative stress, fibrosis, and hypertrophy in chronic ischemia, and mice demonstrate improved cardiac function and increased survival along with increased ketone and glucose substrate metabolism utilization. Depletion of SPTLC3 mechanistically alters the membrane environment and subunit composition of mitochondrial complex I of the electron transport chain, decreasing its activity. Our findings suggest a novel essential role for SPTLC3 in electron transport chain function and a contribution to ischemic injury by regulating complex I activity.

Long-term post-transplantation outcomes in patients with hypertrophic cardiomyopathy: Single-center 35-year experience.

Heart transplantation (HT) is the only option for most patients with end-stage heart failure and hypertrophic cardiomyopathy (HCM) who fail medical therapy. Data on the long-term outcomes post-transplant in HCM individuals remain scarce. We analyzed data of 319 adult patients who underwent HT between 1984 and 2019. Patients were followed for cardiac allograft rejection, cardiac allograft vasculopathy (CAV), death, or re-transplantation. Outcomes of 24 patients with HCM, 160 with ischemic, and 135 with dilated cardiomyopathy were compared. During a mean follow-up of 11.6±7.2 (max 27.8), 16.7±8.2 (max 32.7), and 16.1±9.7 (max 34.6) years after HT in hypertrophic, ischemic, and dilated cardiomyopathy groups, respectively: 10-year survival rate was 67%, 62%, 69%, respectively (p=.04). Post-transplantation, HCM individuals more often than the other two studied groups required prolonged inotropic support (37%, 12%, 17%, respectively, p=.02), temporary mechanical circulatory support (45%, 13%, 14%, respectively, p<.01), and renal replacement therapy immediately post-HT (55%, 19%, 24%, respectively, p<.01). No significant inter-group differences were noted in the 10-year freedom from acute allograft rejection (38%, 46%, 43%, respectively, p=.38) or 10-year freedom from CAV (88%, 78%, 81%, respectively, p=.57). The long-term post-transplant prognosis of adult patients with hypertrophic cardiomyopathy is favorable despite more challenging immediate post-HT course.

Association between anti-cardiac autoantibodies in acute myocarditis and downstream clinical outcomes

Abstract Introduction Myocarditis is an inflammatory heart muscle disease that can result in cardiac dysfunction and arrhythmias. Its aetiology includes infectious, toxic or autoimmune causes. Myocarditis is responsible for sudden cardiac death in young adults (1) and can result in heart failure due to dilated cardiomyopathy in 20% of patients (2). The pathogenesis of myocarditis may involve immune system dysregulation leading to a cascade of inflammation and myocardial damage (3). For those patients that rapidly progress to end-stage dilated cardiomyopathy, an important dilemma is whether there is any prospect of heart function recovery. Therefore, there is an unmet need for a better understanding of key causal pathways and for developing a biological signature of disease progression. Hypothesis The progression of acute myocarditis depends on a persistent adaptive immune response against the heart, leading to ongoing inflammation, myocardial fibrosis and ultimately tissue destruction and remodelling. Aims We sought to explore anti-cardiac IgG serum levels, their temporal profile throughout follow up and their association with clinical and imaging data, in patients presenting with acute myocarditis. Methods We prospectively recruited 80 patients with a clinical diagnosis of acute myocarditis. We measured their total anti-cardiac IgG levels at admisssion, 3- and 12-months follow-up using an enzyme-linked immunosorbent assay (ELISA). We explored the association between the anti-cardiac IgG levels, cardiac MRI parameters (CMR) and clinical data. Results We detect an adaptive immune response against the heart in a subgroup of patients with acute myocarditis. 20% of patients develop high systemic titres of anti-cardiac IgG (OD threshold &amp;gt;0.65), within the first 7 days of presentation (Figure 1a). These patients continue to have persistent and significantly higher anti-cardiac IgG levels at 12 months (Figure 1b). Importantly, patients that mount a strong initial adaptive immune response against the heart, are more likely to show evidence of persistent oedema on CMR at 12 months(Figure 1c). Clinical event rates in our cohort have remained low at five-year follow-up. A small signal exists to indicate potentially higher rates of persistent symptoms (70% vs 47%), hospitalisations for heart failure (12% vs 8%) and new heart failure diagnosis (18% vs 11%), in patients that mount a strong adaptive immune response compared to those that do not. Conclusion A subset of patients with acute myocarditis develops a strong and persistent adaptive immune response against the heart. This may be associated with more myocardial oedema on cardiac MRI, persistent symptoms and higher rates of heart failure diagnoses and hospitalisations. Further work Plasma proteomics (targeted and un-targeted discovery) with validation in myocardial tissue. Analysis of CMR data with a focus on fibrosis assessment. ELISA for IgG subtypes and total IgG against myosin and troponin I.

Genetic Contribution to End-Stage Cardiomyopathy Requiring Heart Transplantation.

Many cardiovascular disorders propel the development of advanced heart failure that necessitates cardiac transplantation. When treatable causes are excluded, studies to define causes are often abandoned, resulting in a diagnosis of end-stage idiopathic cardiomyopathy. We studied whether DNA sequence analyses could identify unrecognized causes of end-stage nonischemic cardiomyopathy requiring heart transplantation and whether the prevalence of genetic causes differed from ambulatory cardiomyopathy cases. We performed whole exome and genome sequencing of 122 explanted hearts from 101 adult and 21 pediatric patients with idiopathic cardiomyopathy from a single center. Data were analyzed for pathogenic/likely pathogenic variants in nuclear and mitochondrial genomes and assessed for nonhuman microbial sequences. The frequency of damaging genetic variants was compared among cardiomyopathy cohorts with different clinical severity. Fifty-four samples (44.3%) had pathogenic/likely pathogenic cardiomyopathy gene variants. The frequency of pathogenic variants was similar in pediatric (42.9%) and adult (43.6%) samples, but the distribution of mutated genes differed (P=8.30×10-4). The prevalence of causal genetic variants was significantly higher in end-stage than in previously reported ambulatory adult dilated cardiomyopathy cases (P<0.001). Among remaining samples with unexplained causes, no damaging mitochondrial variants were identified, but 28 samples contained parvovirus genome sequences, including 2 samples with 6- to 9-fold higher levels than the overall mean levels in other samples. Pathogenic variants and viral myocarditis were identified in 45.9% of patients with unexplained end-stage cardiomyopathy. Damaging gene variants are significantly more frequent among transplant compared with patients with ambulatory cardiomyopathy. Genetic analyses can help define cause of end-stage cardiomyopathy to guide management and risk stratification of patients and family members.

Starting Pediatric VAD Program: Transforming Challenges into Opportunities; A Case Series of a Single Center

Background: The prevalence of heart failure is constantly increasing in both children and adults. End-stage heart failure in children unresponsive to medical therapy has limited treatment options. Surgical options include heart transplantation or implantation of durable ventricular assist devices (VADs). To start the VAD program, it was necessary to train core team members, invite experienced proctors and adjust the organizational approach. Methods: We present our first seven pediatric patients who underwent a VAD implantation with primary indication end-stage dilated cardiomyopathy. Results: The median age on implant was four and a half years and the median duration of VAD support was 39 days with long term survival achieved in three patients. The causes of death were multiorgan failure, thromboembolic events, sepsis, and low cardiac output syndrome. Ischemic stroke was the reason for successful neurointervention during VAD support in two patients. Conclusions: To establish a VAD program, numerous specialties must be included with adequate training and learning for all team members.

COX5A Alleviates Doxorubicin-Induced Cardiotoxicity by Suppressing Oxidative Stress, Mitochondrial Dysfunction and Cardiomyocyte Apoptosis.

Doxorubicin (DOX) as a chemotherapeutic agent can cause mitochondrial dysfunction and heart failure. COX5A has been described as an important regulator of mitochondrial energy metabolism. We investigate the roles of COX5A in DOX-induced cardiomyopathy and explore the underlying mechanisms. C57BL/6J mice and H9c2 cardiomyoblasts were treated with DOX, and the COX5A expression was assessed. An adeno-associated virus serum type 9 (AAV9) and lenti-virus system were used to upregulate COX5A expression. Echocardiographic parameters, morphological and histological analyses, transmission electron microscope and immunofluorescence assays were used to assess cardiac and mitochondrial function. In a human study, we found that cardiac COX5A expression was dramatically decreased in patients with end-stage dilated cardiomyopathy (DCM) compared to the control group. COX5A was significantly downregulated following DOX stimulation in the heart of mice and H9c2 cells. Reduced cardiac function, decreased myocardium glucose uptake, mitochondrial morphology disturbance, reduced activity of mitochondrial cytochrome c oxidase (COX) and lowered ATP content were detected after DOX stimulation in mice, which could be significantly improved by overexpression of COX5A. Overexpression of COX5A effectively protected against DOX-induced oxidative stress, mitochondrial dysfunction and cardiomyocyte apoptosis in vivo and in vitro. Mechanistically, the phosphorylation of Akt (Thr308) and Akt (Ser473) were also decreased following DOX treatment, which could be reserved by the upregulation of COX5A. Furthermore, PI3K inhibitors abrogated the protection effects of COX5A against DOX-induced cardiotoxicity in H9c2 cells. Thus, we identified that PI3K/Akt signaling was responsible for the COX5A-mediated protective role in DOX-induced cardiomyopathy. These results demonstrated the protective effect of COX5A in mitochondrial dysfunction, oxidative stress, and cardiomyocyte apoptosis, providing a potential therapeutic target in DOX-induced cardiomyopathy.

Treatment Strategies for Cardiomyopathy in Children: A Scientific Statement From the American Heart Association.

This scientific statement from the American Heart Association focuses on treatment strategies and modalities for cardiomyopathy (heart muscle disease) in children and serves as a companion scientific statement for the recent statement on the classification and diagnosis of cardiomyopathy in children. We propose that the foundation of treatment of pediatric cardiomyopathies is based on these principles applied as personalized therapy for children with cardiomyopathy: (1) identification of the specific cardiac pathophysiology; (2) determination of the root cause of the cardiomyopathy so that, if applicable, cause-specific treatment can occur (precision medicine); and (3) application of therapies based on the associated clinical milieu of the patient. These clinical milieus include patients at risk for developing cardiomyopathy (cardiomyopathy phenotype negative), asymptomatic patients with cardiomyopathy (phenotype positive), patients with symptomatic cardiomyopathy, and patients with end-stage cardiomyopathy. This scientific statement focuses primarily on the most frequent phenotypes, dilated and hypertrophic, that occur in children. Other less frequent cardiomyopathies, including left ventricular noncompaction, restrictive cardiomyopathy, and arrhythmogenic cardiomyopathy, are discussed in less detail. Suggestions are based on previous clinical and investigational experience, extrapolating therapies for cardiomyopathies in adults to children and noting the problems and challenges that have arisen in this experience. These likely underscore the increasingly apparent differences in pathogenesis and even pathophysiology in childhood cardiomyopathies compared with adult disease. These differences will likely affect the utility of some adult therapy strategies. Therefore, special emphasis has been placed on cause-specific therapies in children for prevention and attenuation of their cardiomyopathy in addition to symptomatic treatments. Current investigational strategies and treatments not in wide clinical practice, including future direction for investigational management strategies, trial designs, and collaborative networks, are also discussed because they have the potential to further refine and improve the health and outcomes of children with cardiomyopathy in the future.

Cardiac iron overload in pediatric oncology and bone marrow transplant survivors.

e22022 Background: Cardiovascular late effects are a leading cause of mortality and morbidity in childhood cancer and Bone Marrow Transplant (BMT) survivors. In patients receiving chronic red blood cell transfusions, excess iron may be deposited in the liver, heart, and pituitary gland. Iron overload cardiomyopathy is characterized as a restrictive physiology with early diastolic dysfunction ultimately progressing to end-stage dilated cardiomyopathy. Iron loading in the heart can also lead to arrhythmias and increase myocardial ischemia reperfusion injury due to increased formation of reactive oxygen species. It is not yet known whether high transfused packed red blood cell (PRBC) volumes in cancer and BMT patients leads to cardiac iron deposition, and whether iron-induced cardiac injury contributes to the known cardiovascular late effects in these patients. Methods: 83 childhood cancer and BMT survivors with elevated serum ferritin levels and subsequent liver Magnetic Resonance (MR) imaging were identified. 18 patients (21.7%) who had liver iron content of &gt; 12mg/g (mean 16.0 ± 7.36 mg/g) also underwent Cardiac MRI (CMR) to determine cardiac iron content. Results: Median transfused blood volume was 393 ml/kg [95% Confidence Interval (CI) 170-780 ml/kg]. All 18 patients had at least one echocardiogram showing normal ventricular ejection fractions [mean 65.1 ± Standard Deviation (SD) 3.53%] and normal shortening fractions (mean 35.4 ± 3.67%). All patients had myocardial iron content within normal ranges (T2* relaxation time mean 35.1 msec ± 7.1 [normal &gt;20 msec], mean ± SD iron content 0.63± 0.2 mg/g dry weight, range 0.5-1.1). There was no association of cardiac iron content with transfused blood volume, anthracycline dose (mg/m2) or liver iron content (Pearson Correlation Coefficients 0.27, 0.29 and 0.89 respectively). Conclusions: Childhood cancer and BMT patients receive multiple PRBC transfusions to treat symptomatic anemia. It is currently unknown whether excess iron deposition in the heart contributes to the cardiac effects of impaired diastolic function and ultimately systolic dysfunction. In this study, 11 of 18 patients (61.1%) with high levels of liver iron had at least 1 other risk factor for the development of future cardiac dysfunction (either anthracycline exposure, radiation to the chest or total body irradiation or both). Larger studies are needed to determine whether oncology patients with high levels of iron deposition in their liver are also at risk for clinically significant cardiac iron loading, and what risk factors may exist for elevated myocardial iron content.

Late left ventricular myocardial remodeling after pulmonary artery banding for end-stage dilated cardiomyopathy in infants: an imaging study

BackgroundUnderstanding the macroscopic biventricular changes induced by pulmonary artery banding (PAB) in children with dilated cardiomyopathy (DCM) represents the first step to unraveling the regenerative potential of the myocardium. We herein investigated the phases of left ventricular (LV) rehabilitation in PAB responders, using a systematic echocardiographic and cardiac magnetic imaging (CMRI) surveillance protocol. MethodsWe prospectively enrolled all patients with DCM treated with PAB from September-2015 at our institution. Among 9 patients, 7 positively responded to PAB and were selected. Transthoracic 2D echocardiography was performed before PAB; and 30, 60, 90, and 120 days after PAB; and at the last available follow-up. CMRI was performed before PAB (whenever possible) and one year after PAB. ResultsIn PAB responders, LV ejection fraction showed a modest 10% increase 30–60 days after PAB, followed by its almost complete normalization after 120 days (median of 20[10–26]% vs 56[44.5–63.5]%, at baseline and 120 days after PAB, respectively). Parallelly, the LV end-diastolic volume decreased from a median of 146(87–204)ml/m2 to 48(40–50)ml/m2. At the last available follow-up (median of 1.5 years from PAB), both echocardiography and CMRI showed a sustained positive LV response, although myocardial fibrosis was detected in all patients. ConclusionsEchocardiography and CMRI show that PAB can promote a LV remodeling process, which starts slowly and can culminate in the normalization of LV contractility and dimensions 4 months later. These results are maintained up to 1.5 years. However, CMRI showed residual fibrosis as evidence of a past inflammatory injury whose prognostic significance is still uncertain.

Alterated gene expression in dilated cardiomyopathy after left ventricular assist device support by bioinformatics analysis.

Heart transplantation is the best treatment for end-stage dilated cardiomyopathy (DCM). Left ventricular assist device (LVAD) support is becoming more prevalent and may delay heart transplantation. Gene expression of the left ventricular myocardium usually changes following LVAD implantation. In this study, we aimed to identify potential biomarkers to determine the prognosis of patients with DCM after receiving LVAD support. We extracted microarray datasets from Gene Expression Omnibus (GEO), including GSE430 and GSE21610. There were 28 paired DCM samples in the GSE430 and GSE21610 profiles. Differentially expressed genes (DEGs) were identified at LVAD implantation and heart transplantation. DEGs were annotated according to Gene Ontology (GO) and analyzed according to the Kyoto Encyclopedia of Genes and Genomes (KEGG) pathway enrichment analysis. A protein-protein interaction (PPI) network was constructed. The top 10 crucial genes were predicted using Cytoscape plugin CytoHubba in conformity with the network degree algorithm. The levels of gene expression and the diagnostic values of crucial genes were confirmed in the clinical datasets. The 28 DEGs were clustered into the GSE datasets. GO annotations and KEGG pathway enrichment analyses revealed that inflammation might be involved. They were associated with correlative inflammation. Combined with PPI networks, these results revealed CytoHubba's top 10 hub genes, including CCL2, CXCL12, CXCL1, CTGF/CCN2, CX3CR1, POSTN, FKBP5, SELE, AIF1, and BMP2. Among them, CCL2, CXCL12, FKBP5, and BMP2 might be considered prognostic and diagnostic biomarkers after LVAD support and have confirmed their validity in clinical datasets. The area under the curve of the four main hub genes was more than 0.85, indicating high diagnostic ability and good prognosis for patients with DCM with LVAD implantation. However, a significant effect of CCL2, CXCL12, FKBP5, and BMP2 expression was not observed on the left ventricular end-diastolic diameter (LVEDD), left ventricular ejection fraction (LVEF), cardiac index (CI), or support time of LVAD. CCL2, CXCL12, FKBP5, and BMP2 could be potential gene biomarkers for patients with DCM after LVAD support. These findings provide critical clues for the therapeutic management of patients with DCM and LVADs. LVEDD, LVEF, CI, and support time of LVAD were not correlated with the expression of these hub genes.

Clustering of Cardiac Transcriptome Profiles Reveals Unique: Subgroups of Dilated Cardiomyopathy Patients

Dilated cardiomyopathy is a heterogeneous disease characterized by multiple genetic and environmental etiologies. The majority of patients are treated the same despite these differences. The cardiac transcriptome provides information on the patient's pathophysiology, which allows targeted therapy. Using clustering techniques on data from the genotype, phenotype, and cardiac transcriptome of patients with early- and end-stage dilated cardiomyopathy, more homogeneous patient subgroups are identified based on shared underlying pathophysiology. Distinct patient subgroups are identified based on differences in protein quality control, cardiac metabolism, cardiomyocyte function, and inflammatory pathways. The identified pathways have the potential to guide future treatment and individualize patient care.

470 MYOCARDIAL FIBROSIS IN ASYMPTOMATIC PATIENTS UNDERGOING SURGERY FOR MITRAL AND AORTIC VALVE REGURGITATION

Abstract Background Chronic heart valve regurgitation induces left ventricular (LV) volume overload, leading to the development of hypertrophy and progressive dilatation of the ventricle to maintain physiological cardiac output. In order to prevent potential irreversible LV structural changes, the identification of the best timing for treatment is pivotal. Objective To assess the presence and extent of fibrosis in myocardial tissue in asymptomatic patients with valvular heart disease (VHD) and preserved LV dimensions and function undergoing cardiac surgery. Methods Thirty-nine patients were enrolled. Sixteen patients were affected by aortic or mitral regurgitation: they were all asymptomatic, undergoing valve surgery according to VHD European Society of Cardiology guidelines. Twentythree patients with end-stage nonischemic dilated cardiomyopathy (DCM) and severe LV dysfunction undergoing cardiac surgery for implantation of a durable left ventricular assist device (LVAD) served as controls. During surgery, VHD patients underwent three myocardial biopsies at the level of the septum, the lateral wall and LV apex, while in LVAD patients the coring of the apex of the LV was used. For both groups, the tissue samples were analyzed on one section corresponding to the apical area. All slides were stained with hematoxylin and eosin and Masson's trichrome staining and further digitalized. The degree of fibrosis was then calculated as a percentage of the total area. Results Of 39 patients, 23 met the inclusion criteria: 12 had mitral or aortic insufficiency with a preserved ejection fraction and 11 had idiopathic dilated cardiomyopathy. Quantitative analysis of apical sections revealed a myocardial fibrosis amount of 10±6% in VHD patients, while in LVAD patients the mean apical myocardial fibrosis rate was 38±9%. In VHD patients, fibrosis was also present in the lateral wall (9±4%) and in the septum (9±6%). Conclusion Our case series study highlights the presence of tissue remodeling with fibrosis in asymptomatic patients with VHD and preserved LV function. According to our results, myocardial fibrosis is present at an early stage of the disease, well before developing detectable LV dysfunction and symptoms. Since the relationship between the progressive magnitude of myocardial fibrosis and potential prognostic implications are not yet defined, further studies on this topic are warranted.

MANAGEMENT OF MAJOR AIRWAY HAEMORRHAGE WITH VENOVENOUS EXTRACORPOREAL MEMBRANE OXYGENATION IN A HEART TRANSPLANT RECIPIENT

<h3>Objective</h3> To report the successful use of venovenous extracorporeal membrane oxygenation in a heart transplant recipient with a catastrophic airway haemorrhage. <h3>Design and methods</h3> Review of hospital records and imaging. <h3>Results</h3> A 56 year-old man with a past medical history of asthma, bronchiectasis and immunoglobulin A deficiency presented with end-stage ischaemic cardiomyopathy and recurrent pulmonary oedema. He was assessed for and underwent a heart transplant. The donor graft was well matched, but a small soft left anterior descending coronary artery plaque was noted at retrieval. In the first 24 hours post-transplant, he had a falling cardiac index followed by dysrhythmias. He was placed on veno-arterial extracorporeal membrane oxygenation (VA ECMO) and underwent PCI to the LAD lesion and started on aspirin and prasugrel. 48 hours later, his oxygenation requirements increased, his chest x-ray showed infiltrates and differential hypoxia (Harlequin Syndrome) was diagnosed. VAV ECMO was established. Overnight following VAV ECMO, fresh blood and clots were suctioned from the endotracheal tube, with falling tidal volumes to the point he was effectively unventilated. A CT scan showed extensive bronchial casts. A rigid bronchoscopy removed the clot. No specific bleeding point was identified, but general ooze from both bronchi was observed. Antiplatelet agents and systemic heparin were stopped, whilst distal limb perfusion catheter heparin was continued. Serial bronchoscopies were performed daily, removing small quantities of clot and applying topical therapies to various bleeding points in the right upper lobe. Tidal volumes remained under 100ml. Disseminated intravascular coagulation was diagnosed and product replacement guided by laboratory results and thromboelastography was undertaken. With improving cardiac function, arterial decannulation was achieved, leaving the patient on VV ECMO. This was continued for a further week with repeated flexible bronchoscopy and clot retrieval. Bleeding resolved after several days with conservative therapy, avoiding surgical or interventional radiological procedures. Improvements in tidal volumes were observed and eventually VV ECMO was successfully weaned. Aspirin was restarted as single antiplatelet therapy. He subsequently made a good recovery. <h3>Discussion</h3> VV ECMO is well established as a treatment in respiratory failure and pulmonary haemorrhage. However, use of VAV and VV ECMO for a major airway bleed in a heart transplant patient has not, to our knowledge, been previously described. The risks of running circuits without anticoagulation in patients totally dependent on them are high and managing this risk, alongside the new stent in a crucial coronary artery, were challenging. This case highlights the importance of balancing thrombosis and bleeding risk, especially in the context of new coronary stents, and has prompted consideration whether short-acting agents such as tirofiban may have a role in these especially high-risk cases.

Time course, factors related to, and prognostic impact of venoarterial extracorporeal membrane flow in cardiogenic shock.

Venoarterial extracorporeal membrane oxygenation (VA-ECMO) is currently one of the most used devices in refractory cardiogenic shock. However, there is a lack of evidence on how to set the 'optimal' flow. We aimed to describe the evolution of VA-ECMO flows in a cardiogenic shock population and determine the risk factors of 'high-ECMO flow'. A 7year database of patients supported with VA-ECMO was used. Based on the median flow during the first 48h of the VA-ECMO run, patients were classified as 'high-flow' or 'low-flow', respectively, when median ECMO flow was ≥3.6 or <3.6L/min. Outcomes included rates of ventilator-associated pneumonia, ECMO-related complications, days on ECMO, days on mechanical ventilation, intensive care unit and hospitalization lengths of stay, and in-hospital and 60day mortality. Risk factors of high-ECMO flow were assessed using univariate and multivariate cox regression. The study population included 209 patients on VA-ECMO, median age was 51 (40-59) years, and 78% were males. The most frequent aetiology leading to cardiogenic shock was end-stage dilated cardiomyopathy (57%), followed by acute myocardial infarction (23%) and fulminant myocarditis (17%). Among the 209 patients, 105 (50%) were classified as 'high-flow'. This group had a higher rate of ischaemic aetiology (16% vs. 30%, P=0.023) and was sicker at admission, in terms of worse Simplified Acute Physiology Score II score [40 (26-58) vs. 56 (42-74), P<0.001], higher lactate [3.6 (2.2-5.8) mmol/L vs. 5.2 (3-9.7) mmol/L, P<0.001], and higher aspartate aminotransferase [97 (41-375) U/L vs. 309 (85-939) U/L, P<0.001], among others. The 'low-flow' group had less ventilator-associated pneumonia (40% vs. 59%, P=0.007) and less days on mechanical ventilation [4 (1.5-7.5) vs. 6 (3-12) days, P=0.009]. No differences were found in lengths of stay or survival according to the ECMO flow. The multivariate analysis showed that risk factors independently associated with 'high-flow' were mechanical ventilation at cannulation [odds ratio (OR) 3.9, 95% confidence interval (CI) 2.1-7.1] and pre-ECMO lactate (OR 1.1, 95% CI 1.0-1.2). In patients with refractory cardiogenic shock supported with VA-ECMO, sicker patients had higher support since early phases, presenting thereafter higher rates of ventilator-associated pneumonia but similar survival compared with patients with lower flows.