Abstract Background Cardiac amyloidosis (CA) is an increasingly recognized cause of human heart failure. Up to 16% of patients with severe aortic stenosis (AS) undergoing transcatheter valve replacement have been reported to suffer concomitant transthyretin CA (ATTR). Since the diagnosis of CA implies distinct therapies with prognostic relevance, early diagnosis of CA is crucial. Different parameters have been described to improve screening accuracy for detection of CA, but it is unknown whether these parameters are valid, and the prevalence of CA is stable throughout the spectrum of AS. Purpose To validate screening parameters for the detection of CA in mild, moderate and severe AS. Methods Patient 65 years and above undergoing echocardiography with mild to severe AS, defined as calculated valve orifice area <2 cm2 by velocity-time-integral, and an intraventricular septum thickness > 11mm, fulfilling at least one of two additional criteria (Sokolow-Lyon-Index to left ventricular mass index ratio < 1.5 or stroke volume index < 35 ml/m2) were prospectively included and screened for CA using bone scintigraphy and immunofixation in blood and urine. Results 57 patients were included and completed the diagnostic work-up. Mean age was 83 ± 0.7 years and 71% were male. Overall, 15 (26%) of patients were diagnosed with CA (12 with ATTR and 3 with light-chain CA, Figure1A). 17 patients had mild, 21 had moderate and 19 patients were diagnosed with severe AS. Among patients with mild AS 41% were diagnosed with CA, whereas only 24% of patients with moderate and 16% of patients with severe AS suffered CA (Figure 1B), these results did not show statistically significant differences (p= 0.2, by Chi-Square Quadrat test). Patients with CA were less likely to have NYHA classes I or II (20 vs. 57%, p= 0.03), had higher values of NT-proBNP (4572 [2323; 6044] vs. 817 [589; 2571], p< 0.001) and high-sensitive troponin (66 [47; 103.5] vs. 22.5 [17; 33.6], p< 0.001) and were more likely to have an atrioventricular block of any degree (60 vs. 26%, p=0.04). Conclusion Prevalence of CA among patients fulfilling the criteria of this screening algorithm seems to be high independent of AS severity. Clinicians should not only focus on patients with severe AS to detect CA early. Further research is needed to estimate the prevalence of CA among all patients with AS. Figure 1 A: Among patients with an age >65 years, IVS >11mm, AS and SLI/LVMMI >1.5 or SVI <35 ml/m2 26% (red area) of patients were diagnosed with CA (n= 57). B: In patients with mild AS 41% were diagnosed with CA, whereas in patients with moderate AS only 24% and in patients with severe AS 16% had CA. These differences did not show statistical significance (p= 0.2). IVS: intraventricular septum, AS: aortic stenosis, SLI: Skolow-Lyon-Index, LVMM= left ventricular myocardial mass index, SVI: stroke volume index, CA: cardiac-amyloidosis. (Statistics performed by chi-square test using GraphPad Prism 9.0).

Abstract Introduction/Purpose Recent studies suggest that the ketone bodies (KB) beta-hydroxybutyrate (HBA) and acetoacetate (ACA) are relevant substrates for myocardial energy metabolism in heart failure (HF). However, the amount of KB-dependent mitochondrial respiration in HF has not yet been quantified. High-resolution respirometry (HRR) is the gold-standard method for quantifying substrate-dependent mitochondrial oxidative capacity. Therefore, we aimed to evaluate the association between myocardial KB-dependent oxidative capacity and human HF using HRR. Methods The primary endpoint of this single-center prospective cohort study was KB-dependent and overall mitochondrial oxidative capacity in permeabilized myocardium. We used two different protocols for our measurements. In the first HRR protocol, conventional respirometry substrates including fatty acids, complex I- and complex II substrates were used to quantify the maximum coupled oxidative phosphorylation capacity (OXPHOS). Leak respiration was quantified using oligomycin to calculate the respiratory control ratio (RCR, state 3/state 4o), and leak control ratio (LCR, state 4o/state u). In the second protocol which was recently established by our working group, HBA and ACA were used as respirometry substrates to quantify KB-dependent respiration down to the enzyme level. The relative contribution of the KBs was obtained by comparing HBA- and ACA-derived respiration to OXPHOS. We applied both protocols to myocardial samples from individuals with advanced HF (HF group, catheter-acquired endomyocardial biopsies from non-ischemic HF patients or samples of explanted hearts collected during orthotopic heart transplantation surgery in end-stage heart failure patients) as well as previously heart transplanted individuals without current heart failure (Control group). Results Controls and HF had similar demographic characteristics, with comparable age distribution (mean±SD, 56.3±10.3 vs. 54.2±10.7 years, p=0.36), sex (68.75% vs. 66.67% male, p=0.87), or body mass index (25.0±5.8 vs. 29.0±10.6 kg/m2, p=0.08) and differed significantly in cardiac index (3.06±0.67 vs. 1.93±0.44) and ejection fraction (55.8±10.2 vs. 26.6±9.1) (both p<0.0001). The HF group exhibited lower OXPHOS and respiration for all substrate combinations tested (Fig. 1A). In contrast, KB-dependent respiration did not differ between HF and controls (Fig. 1B). The relative HBA-dependent respiration (Fig. 1C) and the relative and absolute ACA-dependent respiration (Fig. 1C and D) were higher in the HF group compared to controls. Mitochondrial uncoupling (LCR) (0.47±0.29 vs. 0.44±0.09 [AU], p=0.79) and coupling efficiency (RCR) (2.75±1.38 vs. 2.11±0.39 [AU], p=0.15) were not different between the groups. Conclusion These findings suggest that mitochondria in the failing heart can utilize KBs for OXPHOS to a greater extent and further hint towards KB metabolism as a potential therapeutic target for HF.

Purpose: Limited data exist on perioperative inotropic therapy for heart transplantation (HTx). Currently, both epinephrine and dobutamine are used regularly and the decision is often based more on personal preference than on scientific background.

Abstract Background Recent studies suggest that mitral regurgitation (MR) is a dynamic condition influenced by global and regional left ventricular (LV) remodeling as well as mitral valvular deformation. Exercise testing plays a substantial role in assessing the hemodynamic relevance of MR and is recommended by current guidelines. Handgrip exercise may serve as alternative exercise intervention to bicycle exercise, as it is easy to perform even bedside. However, there are no data yet, on the prevalence, mechanisms and prognostic impact of dynamic MR in patients with dilated cardiomyopathy using isometric exercise testing. Aims We aimed to assess the prevalence, hemodynamic consequences, and prognostic impact of exercise-induced changes in MR in patients with hypokinetic non-dilated and dilated cardiomyopathy. Methods Patients with hypokinetic non-dilated and dilated cardiomyopathy and at least mild MR who underwent handgrip echocardiography at the University Hospital Duesseldorf between January 2018 and September 2021 were enrolled.Patients were followed-up for one year to assess clinical outcomes. We assessed all-cause mortality, HF-associated hospitalizations, MV surgery, transcatheter edge-to-edge repair (TEER), left ventricular assist device implantation and heart transplantation during follow-up. Results Fifty-eight patients were included (mean age 70±15 years; 41% female; mean LVEF 37±10%). At rest, 28 patients (48%) presented with mild MR, and 30 patients (52%) had moderate MR. Fifteen patients (26%) with non-severe MR at rest, developed dynamic severe MR during handgrip exercise. Patients with dynamic severe MR had advanced MR at rest, larger left atrial dimensions, and increased mitral annulus diameter (all p<0.01). During exercise, LVEDVi, LVESVi and parameters of local left ventricular remodeling (tenting height, tenting area) were increased in patients with dynamic severe MR compared to those with non-severe MR (all p<0.05). During one-year follow-up, there was no difference regarding all-cause mortality and HF hospitalizations in patients with dynamic severe MR and non-severe MR (Log-rank test Chi2 0.262; p=0.609)(Figure 1). However, patients with dynamic severe MR more often underwent mitral valve surgery/intervention than patients with non-severe MR (Log-rank test Chi2 29.41; p<0.001)(Figure 1). Conclusion Our results demonstrate that the evaluation of non-ischemic MR only at rest underestimates the full severity of the lesion. Handgrip exercise unmasks severe MR in every fourth patient with non-severe MR at rest. These data may have implications for therapeutic decision-making in symptomatic patients with hypokinetic non-dilated and dilated cardiomyopathy and non-severe MR at rest. TEER might present an effective treatment option to improve clinical outcomes in patients with non-ischemic cardiomyopathy and non-severe MR at rest but dynamic severe MR during exercise.Figure 1

Purpose: Outcomes after heart transplantation (HTx) may depend on the time of cardiac surgery, especially if comparing routine-hour and off-hour shifts. This study sought to examine temporal trends in survival and outcome differences between on-hours and off-hours HTX.

Purpose: Posttransplantation lymphoproliferative disease (PTLD) after solid organ transplantation is a serious complication of immunosuppressive treatment and normally associated with high mortality. A correlation of PTLD incidence and Epstein-Barr virus (EBV) infection could be proven. In renal and in lung transplantation, the use of immunoglobulin (Ig) cytomegalovirus (CMV) prophylaxis, which also contains anti-EBV antibodies, resulted in a significant lower incidence of PTLD. Therefore we aimed to analyze these outcomes in our patients after heart transplantation (htx).

Abstract Objective Several Risk assessment tools have been developed to help predict mortality after heart transplantation. While validated within their regional transplant cohorts, it remains unclear whether they can also be applied to other cohorts. We therefore aimed to test and compare the predictive value of an US-Score validated in the UNOS Database by Joyce et al., a French Score by Jasseron et al., and the BO-Score within the Eurotransplant area developed by Schramm et al. Methods We applied the three scores to our cohort using published model coefficients and variables (see Figure 1 for distribution). The initial BO-Score as well as the French Score were hereby modified to produce positive integer values within our cohort (mod. French Score = [initial French Score + 2.24]x10, mod. BO Score = [initial BO initial score+10]x3). C-statistics using ROC-analysis (Figure 2) were used to compare the three scores regarding their ability to discriminate between 30-day, 1 year and 5-year survivors and non-survivors within our heart transplant cohort. Results The French Score performed best predicting the 1 survival with an AUC of 0.69 [95% CI: 0.59-0.79, p<0.0001], followed by the BO-Score with 0.66 (95% CI: 0.56-0.77, p=0.003) and the US-Score with an AUC of 0.67, CI 0.57-0.76, p=0.02). Regarding 30-day-Survival, only the French Score with an AUC of 0.64 [95% CI: 0.52-0.76, p=0.006] as well as the BO-Score with 0.71 (95% CI: 0.60-0.81, p=0.008) could predict mortality sufficiently, while the US-Score could not discriminate statistically significant between survivors and non-survivors (AUC 0.64, CI 0.52-0.76, p=0.06). All scores performed worst predicting 5-year survival, with only the BO-Score being statistically significant (AUC 0.61, 95% CI: 0.56-0.77, p=0.003). Conclusion In our heart transplant cohort, the available donor recipient risk assessment tools performed best predicting 1 year survival, with worse and heterogenous results for 30 day or 5 year survival. Further developments will have to incorporate risk factors not yet taken into account in order to make even more reliable predictions, especially for the Eurotransplant area.Figure 1 and 2

Abstract Objective Optimal immunosuppression is an essential component of the best possible long-term survival after heart transplantation (HTX). Optimally patient-tailored immunosuppression is standard in Tx follow-up, balancing harmful side effects and preventing rejection episodes. Hereby, stable blood levels, as well as a stable and calculable absorption rate, is essential. Tacrolimus additionally has a narrow therapeutic range and is particularly difficult to dose stably. It has been shown that interindividual differences in absorption exist among various immunosuppressants, making adequate minimum levels and the avoidance of rejection events more difficult. For other solid organ transplantation procedures there are already studies on the proportion of patients (so-called "fast metabolizers") who experience different kinetics due to very rapid resorption. We here therefore aim to investigate the potential impact of the tacrolimus metabolizer status on outcome in a HTx cohort. Methods We defined fast metabolizers by a low concentration to dose ratio (C/D ratio) of <1.05. The C/D ratio was determined according to the following formula: C/D ratio (ng/ml x 1/mg) = Tacrolimus through level (ng/ml) / daily Tacrolimus dose (mg). We included as a first step here 57 patients undergoing HTx in our center between 09/2010 and 10/2016 and calculated the C/D ratio retrospectivley from routine follow-ups. In both groups baseline characteristics, perioperative parameters and survival after 1 and 5 years after Tx were collected. Results We identified 24 patients (42%) as fast metabolizers and 33 patients as standard metabolizers (58%). The metabolizer status did not significantly correlate with reduced survival of the recipient up to 5 years in Kaplan-Meier-Analysis (Figure 1,A, Log Rank p=0.68). Additionally, regression analysis could not detect an association of 1-year-survival and C/D ratio or the fast metabolizer status definition (HR 1.1, 95% CI 0.17-7.2, p=0.92). Moreover, using ROC-analysis, no clear other cut-off for C/D ratio other than the used published definition (<1.05) could be derived (Figure 1,B, AUC 5-year survival 0.53, p = 0.72). Additionally, these parameters did not change significantly also when focusing on speficic substances with different pharmacodynamics such as Prograf (two doses per day) or Advagraf (delayed release, one dose per day). We could also not detect associations between C/D ratio or metabolizer status and unfavorable outcomes such as cellular or clinical relevant rejection episodes. Conclusion In this retrospective analysis, neither the metabolizer status or the raw tacrolimus concentration to dose ratio was associated with altered survival or outcome after heart transplantation. As we present here a yet small number of investigated patients (pilot study) with a potential era bias by currently not including advances in medication optimization over the last years, future studies are needed to elucidate this phenomen further.

Abstract Background Mitral regurgitation (MR) is frequent in patients with ischemic heart disease and carries a dismal prognosis. Previous studies already demonstrated the prognostic benefit of bicycle exercise testing in patients with ischemic MR. Thus, current guidelines emphasize the role of exercise testing in patients with valvular heart disease. Isometric handgrip exercise resembles an alternative exercise intervention, that can also be performed in frail, comorbid patients. Until now, there are no data on the prognostic impact of handgrip echocardiography in heart failure patients with ischemic MR. Purpose To assess the prognostic benefit of isometric handgrip testing in heart failure patients with ischemic MR. Methods We prospectively enrolled patients with ischemic cardiomyopathy (left ventricular ejection fraction <50%) and at least mild MR that underwent echocardiography at rest and during handgrip exercise between January 2019 and September 2021. Patients were followed-up for one year to assess clinical outcomes. The combined endpoint included all-cause mortality, heart failure hospitalisation, ventricular assist device implantation (VAD), heart transplantation and mitral valve (MV) surgery/intervention. Results We included 133 patients (mean age was 75±10 years, 21% were female). Seventy patients (53%) presented with mild MR, while 54 patients had moderate MR (41%), and 9 patients (7%) showed severe MR at rest. Twenty-five patients (20%) with non-severe MR at rest, developed severe MR during handgrip exercise. One-year follow-up (median 321 (162-427) days) was complete in 128 patients (96%). Seventy-one patients (56%) experienced an adverse event: 13 patients (10%) died, 33 patients (26%) were re-admitted to hospital due to heart failure symptoms, 30 patients (24%) underwent MV transcatheter edge-to-edge repair, six patients (5%) received MV surgery, one patient (1%) underwent VAD implantation, and another three patients (4%) underwent heart transplantation. According to MR severity at rest, there was no difference in outcomes in patients with mild, moderate and severe MR (p=0.189). As expected, patients with severe MR at rest more often tended to undergo mitral valve surgery/interventions compared to the other groups (p=0.064). However, patients with non-severe MR at rest and exercise-induced severe MR presented with adverse outcomes similar to patients with severe MR at rest (p=0.005). Furthermore, patients with severe MR at rest and patients with dynamic severe MR underwent mitral valve surgery/interventions more frequently than patients with non-severe MR (p<0.001). Conclusion(s) In heart failure patients with ischemic MR, isometric handgrip testing unmasks severe MR in approximately every fifth patient with non-severe MR at rest. These patients showed similar clinical outcomes as compared to patients with severe MR already at rest. Thus, handgrip exercise testing might be a useful tool to guide further therapeutic decision making.

Purpose: The H 2 FPEF scoring system was developed to facilitate the diagnosis of heart failure with preserved ejection fraction (HFpEF) by providing a probability for the diagnosis from demographic and clinical variables.However, the association of the H 2 FPEF score with clinical features of HF is not well defined.We sought to understand the relationship between H 2 FPEF score and submaximal exercise capacity amongst patients with HFpEF.Methods: The Screening for Cardiac Amyloidosis with Nuclear imaging in Minority Populations study (SCAN-MP) is a multicenter study enrolling self-identified Black and Hispanic patients with heart failure, which seeks to determine the prevalence of transthyretin cardiac amyloidosis.SCAN-MP participants enrolled to date without cardiac amyloidosis and with LVEF ≥ 50% were assessed for their H 2 FPEF score.We evaluated the association between H 2 FPEF score and six-minute walk test (6MWT) distance in univariable and multivariable linear regression.Results: Among the 222 participants (72 § 8.6 years, 49% female) included in this analysis, the average H 2 FPEF score was 5 § 2.1.In multivariable analysis, after adjusting for significant univariable predictors including age, sex, height, NYHA class, and estimated pulmonary artery systolic pressure, baseline H2FPEF score remained a significant predictor for 6MWT distance (Table ); every one unit increase in H 2 FPEF score was associated with a 10m decrease in distance walked in 6 minutes.Conclusion: Baseline H 2 FPEF score correlates with 6MWT distance amongst Black and Hispanic patients with HFpEF.

PurposeIt was reported that mRNA-based Covid-19 vaccines rarely cause myocarditis. Although endomyocardial biopsy (EMB) is considered the gold standard for diagnosing myocarditis, no standardized study has been performed after Covid-19 vaccination in humans. Because routine EMB is frequently performed in heart transplant recipients (HTX), we aimed here to investigate effects of Covid-19 vaccination by analyzing myocardial inflammation with state-of-the-art quantitative immunohistochemistry.MethodsConsecutive patients after HTX who underwent routine EMB at a median of 167 days before and 136 days after the first Covid 19 vaccination with an mRNA vaccine were included and divided into groups with and without postvaccination inflammatory response, defined as increased CD3+ lymphocyte count >14/ mm2. Patients with evidence of rejection (ISHLT grade >1) or >14 CD3+ lymphocytes/mm2 at baseline were excluded.ResultsThe final analysis included 46 patients with a mean age of 63 years and a time after HTX of 2.4 years. Thirty-six (78%) patients remained below the threshold of 14 CD3+ lymphocytes/mm2. However, in 10 (22%) recipients, we detected significant leukocyte infiltration by quantitative analysis of EMB after vaccination (4 vs. 33.7 leukocytes/ mm2, p=0.001). The groups did not differ with respect to age (63 vs. 57 years, p=0.21), body mass index (25 vs. 24 kg/m2, p=0.24), NYHA class (≥2 at 19 vs. 10%, p=0.4), NT-ProBNP levels (592 vs. 514 ng/l, p=0.55) or myocardial CD3+ cell count (4.9 vs. 2.6 cells/mm2, p=0.07) before vaccination. Patients with leukocyte infiltration remained clinically inapparent with stable NYHA class (≥2 in 10 vs. 20%, p=0.99) and did not have increased NT-ProBNP levels (514 vs. 478 ng/l, p=0.03). No hospitalizations for suspected myocarditis were reported.ConclusionFor the first time, we report subclinical myocardial leukocyte infiltration after Covid-19 mRNA vaccination in one in five patients without clinical sequelae during the short observation period. It was reported that mRNA-based Covid-19 vaccines rarely cause myocarditis. Although endomyocardial biopsy (EMB) is considered the gold standard for diagnosing myocarditis, no standardized study has been performed after Covid-19 vaccination in humans. Because routine EMB is frequently performed in heart transplant recipients (HTX), we aimed here to investigate effects of Covid-19 vaccination by analyzing myocardial inflammation with state-of-the-art quantitative immunohistochemistry. Consecutive patients after HTX who underwent routine EMB at a median of 167 days before and 136 days after the first Covid 19 vaccination with an mRNA vaccine were included and divided into groups with and without postvaccination inflammatory response, defined as increased CD3+ lymphocyte count >14/ mm2. Patients with evidence of rejection (ISHLT grade >1) or >14 CD3+ lymphocytes/mm2 at baseline were excluded. The final analysis included 46 patients with a mean age of 63 years and a time after HTX of 2.4 years. Thirty-six (78%) patients remained below the threshold of 14 CD3+ lymphocytes/mm2. However, in 10 (22%) recipients, we detected significant leukocyte infiltration by quantitative analysis of EMB after vaccination (4 vs. 33.7 leukocytes/ mm2, p=0.001). The groups did not differ with respect to age (63 vs. 57 years, p=0.21), body mass index (25 vs. 24 kg/m2, p=0.24), NYHA class (≥2 at 19 vs. 10%, p=0.4), NT-ProBNP levels (592 vs. 514 ng/l, p=0.55) or myocardial CD3+ cell count (4.9 vs. 2.6 cells/mm2, p=0.07) before vaccination. Patients with leukocyte infiltration remained clinically inapparent with stable NYHA class (≥2 in 10 vs. 20%, p=0.99) and did not have increased NT-ProBNP levels (514 vs. 478 ng/l, p=0.03). No hospitalizations for suspected myocarditis were reported. For the first time, we report subclinical myocardial leukocyte infiltration after Covid-19 mRNA vaccination in one in five patients without clinical sequelae during the short observation period.

Purpose The CRP/Albumin-Ratio (CAR) correlates with outcomes in various perioperative and intensive care settings. We here aim to explore the potential assocation of preoperative CAR on outcome and survival after heart transplantation (HTx). Methods We screened all patients undergoing HTx in our center between 09/2010 and 05/2022 (n=247), and included 147 patients with complete CAR-data pre HTx. The cohort (table 1) was divided in recipients with low (n=86) and high (n=88) CAR, using 0.185 as cut-off value, calculated via ROC-analysis (Fig. 1A, AUC .73). Logistic regression as well as Kaplan-Meier-survival was used for association of pre-operative CAR and survival. Results Recipients with high CAR were more frequently on the high-urgency (HU) waiting list (61% vs. 31%, p=.0001), had longer duration of surgery (434 min vs. 395 min, p=.006), more severe infections post HTx (34% vs. 15%, p=.004) and increased need for ECLS-support post HTx (40% vs. 21%, p = .008). Logistic[DO1] regression analysis between high and low CAR, covariable-adjusted, revealed significant independent association of CAR and reduced 30-day (unadjusted HR 3.6, 95% CI 1.8-7.1), p <.0001; adjusted HR 2.9, 95% CI 1.4-5.9, p=.003) and 1-year (unadjusted HR 3.4, 95% CI 1.7-6.8, p=.001; adjusted HR 2.8, 95% CI 1.4-5.6, p=.005) survival after HTx. These results were confirmed by Kaplan-Meier survival up to 5-years after HTx in patients with high CAR (see Fig 1B, p <.001). Conclusion The CRP/Albumin-Ratio in recipients prior to HTx is strongly and independently associated with worse postoperative outcome and reduced survival up to 5 years after heart transplantation.

Abstract Background/Introduction With the growing prevalence of prediabetes in developed countries, complications of this predecessor of diabetes mellitus type 2 become increasingly important for medical research and practice. Prediabetes is defined as impaired fasting glucose (IFG) and/or impaired glucose tolerance (IGT) and may also incorporate elevated hemoglobin A1. While overt type 2 diabetes is a well-established risk factor and can even be the cause of cardiac failure, this is not yet proven for prediabetes. Mitochondrial impairment is a key pathomechanism in heart failure, but it remains uncertain, whether prediabetes impairs myocardial energy metabolism in humans just as type 2 diabetes does. Purpose We aimed to scrutinize the impact of prediabetes on myocardial mitochondrial metabolism and cardiac function. Methods We included 50 heart transplant recipients with normal glucose tolerance (GT, n=25), prediabetes (n=8, 3 IFG and 5 IGT) or type 2 diabetes mellitus (T2DM, n=17), who had received a healthy donor heart from a non-diabetic donor. In this cohort, the impact of the recipients' metabolism should be displayed in the donor heart after transplantation. We performed oral glucose tolerance tests to assess the diabetes status, and cardiac magnetic resonance imaging to assess cardiac systolic and diastolic function, circulating biomarkers of oxidative stress in serum samples (thiobarbituric acid reactive substances (TBARS) and redox potential), as well as global T2 relaxation times as a marker of myocardial inflammation. In transcatheter endomyocardial biopsies, we assessed myocardial mitochondrial oxidative capacity using high-resolution respirometry and myocardial mRNA expression of nuclear factor kappa B p105 subunit (NFKB1). Results GT and IFG/IGT patients exhibited comparable demographic and clinical characteristics, whereas T2DM had higher BMI, glycemia, triglycerides and creatine kinase (all p<0.05). None of systolic (p=0.99), diastolic cardiac function (p=0.81), myocardial NFKB1 expression (p=0.74), circulating oxidative stress markers (p=0.94 and 0.95) or cardiac T2 relaxation times (p=0.99) were altered in IFG/IGT compared to GT, but diastolic strainrate was impaired (p=0.03) and circulating oxidative stress (TBARS: p=0.03, redox potential: p=0.04) were higher in T2DM than in GT. However, myocardial mitochondrial function stood out to be already impaired in IFG/IGT to a similar extend as in T2DM. This particularly applied to substrates of mitochondrial complex I (GT vs. IFG/IGT vs. T2DM: 126±7 vs. 89±12 vs. 93±6 pmol s–1 mg–1. p=0.02) and II (188±13 vs. 123±17 vs. 138±11 pmol s–1 mg–1. p=0.02). Intrinsic uncoupling was not altered in IFG/IGT but tended to be higher in T2DM (leak control ratio: 0.49±0.02 vs. 0.46±0.06 vs. 0.57±0.04 [arbirary units]). Conclusion Our findings point towards mitochondrial impairment as a predecessor of overt heart failure in prediabetes and may represent an early footprint of prediabetic cardiomyopathy. Funding Acknowledgement Type of funding sources: None.

Abstract Background Roughly one third of cases of chronic heart failure (HF) are caused by genetic predisposition, metabolic stress and cardiac inflammation. Animal studies suggest that heart-reactive autoantibodies, most notably those directed against G-protein-coupled receptors (GPCR), could also play a pathogenetic role in the disease. However, so far, a causal link between humoral GPCR-autoimmunity and human non-ischemic heart failure other than Chagas' cardiomyopathy remains unclear. Purpose Here, we investigated possible associations of GPCR autoantibodies with inflammatory, hemodynamic, metabolic and functional parameters in patients with chronic non-ischemic HF unrelated to Chagas' disease. Methods We prospectively included 95 patients with newly diagnosed non-ischemic heart failure of unknown origin. Basic cardiac characterization comprised transthoracic echocardiography, cardiac magnetic resonance imaging, coronary angiography and right heart catheterization with endomyocardial biopsy. Mitochondrial oxidative phosphorylation capacity and coupling was measured using high-resolution respirometry in permeabilized myocardial fibers. A panel of candidate GPCR-autoantibodies was determined by validated and certified immune-assays in peripheral venous blood of the HF-patients and 60 matched healthy individuals. Results were normalized to total IgG. Results Among 10 candidate GPCR-autoantibodies determined, only autoantibodies for α1-adrenergic receptor (α1AR), β1-adrenergic receptor (β1AR), muscarinic receptor M5 (M5AR), angiotensin II receptor type 1 (AT1R) and type 2 (AT2R) exhibited HF-associated alterations: Autoantibodies against β1AR, M5R and AT2R were increased. Autoantibodies against α1AR and AT1R were decreased (Figure). These alterations were significant (p<0.01), but not, or only weakly, correlated with markers of cardiac inflammation, cardiac damage, hemodynamics, endomyocardial histology or left ventricular inflammation judged by T2-mapping. However, in HF-patients, increased AT2R autoantibodies were associated with improved myocardial mitochondrial coupling (r=−0.27, p=0.021), and decreased AT2R autoantibodies were associated with insulin resistance (r=−0.24 p=0.027). Conclusion(s) Some previously postulated alterations of GPCR autoantibodies were confirmed in thoroughly characterized HF-patients. However, association of these alterations with cardiac function was not traceable, which argues against a specific pathogenic role. Our data are compatible with multifaceted interactions of GPCR-autoantibodies with the myocardium and potentially with glucose metabolism, possibly indicating a disease-modifying or compensatory role. Funding Acknowledgement Type of funding sources: Public Institution(s). Main funding source(s): Research comission of the Heinrich-Heine University Duesseldorf

Abstract Background Mitochondrial dysfunction is a driving factor in the development of heart failure (HF) and relates to poor cardiac function. Through elevated oxidative stress it is linked to myocardial inflammation. Both mechanisms promote the development of cardiac fibrosis, a key contributor to adverse outcomes in ischaemic and non-ischaemic HF. Differences in myocardial mitochondrial function and inflammation between patients with ischaemic and non-ischaemic HF have been indicated. While immunosuppression in non-ischaemic HF with myocardial inflammation has improved long-term results, little is known about possible benefits in ischaemic HF. Purpose We hypothesised that: 1. Myocardial lymphocytic inflammation and fibrosis differ in patients with HF due to ischaemic cardiomyopathy (ICM) compared to patients with dilated cardiomyopathy (DCM). 2. Inflammation and fibrosis are associated with markers of mitochondrial dysfunction. Methods Myocardial tissue specimens were obtained from the left ventricular (LV) apex of 65 patients (n[ICM] = 33, n[DCM] = 32) with HF requiring an LV assist device or heart transplantation. We assessed oxidative phosphorylation capacity (OXPHOS) via high resolution respirometry in saponine-permeabilised myocardial fibres (OROBOROS Oxygraph-2k). Reactive oxygen species (ROS) production was measured fluoroscopically via the Amplex Red method. Immunohistochemistry staining for CD3 was performed on snap-frozen tissue and digitally analysed. Azan staining was used for quantification of fibrotic area. Statistical analysis was conducted with GraphPad Prism v9.0 and IBM SPSS v27.0. Results ICM and DCM patients did not differ significantly regarding age (60.9±5.4 vs. 55.8±12.4 years, p=0.11), sex (91% vs. 90% male, p=0.93), BMI (27.6±5.1 vs. 26.5±6.0 kg/m2, p=0.82), or diabetic status (31% vs. 20% Type 2 Diabetes mellitus, p=0.31). Tissue specimens of ICM patients displayed about three times larger fibrotic areas compared to DCM (20.9±21.2 vs. 7.2±5.6%, p=0.001). Cellular inflammation (>14 CD3+ cells/mm2) was significantly more common in ICM than DCM patients. (27 vs. 6%, p=0.024). Inflammation and fibrosis did not correlate significantly (r=0.09, p=0.46). Fibrosis was not associated with OXPHOS capacity (r=−0.129, p=0.33). In patients with inflammation, OXPHOS capacity was lower compared to patients without inflammation (92.3±40.1 vs. 131.6±55.6 pmol/(s*mg), p=0.031) and inflammation was associated with lower OXPHOS capacity (r=−0.296, p=0.019). There was a trend towards lower electron transfer capacity in patients with inflammation (98.6±43.1 vs. 129.7±48.3 pmol/(s*mg), p=0.053). ROS production was not significantly different between tissue specimens with or without inflammation (0.51±0.21 vs. 0.67±0.33 pmol/(s*ml), p=0.17). Conclusions Myocardial cellular inflammation is prominent in ICM patients and relates to impaired mitochondria. Future studies may evaluate possible benefits from immunosuppression in ICM patients. Funding Acknowledgement Type of funding sources: Public grant(s) – National budget only. Main funding source(s): German Research Foundation (DFG)

Fragestellung Nuclear factor kappa-B (NfκB) wird in präklinischen Studien eine wichtige Rolle bei kardialer Fibrose und Kardiomyopathien zugeschrieben. Die Aktivierung von NfκB, unter anderem durch geschädigte Mitochondrien, triggert inflammatorische Signalwege im Myokard. Es ist jedoch unklar, ob ein Zusammenhang von NfκB mit der Mitochondrienfunktion des Myokards bei nicht-ischämischer Diabetes-assoziierter Kardiomyopathie besteht. Wir prüften, ob die ventrikuläre myokardiale NfκB-Expression im Menschen (1) durch Typ 2 Diabetes Mellitus (T2DM) induziert wird und (2) mit einer eingeschränkten myokardialer Mitochondrienfunktion assoziiert ist.

Abstract Background Diabetic cardiomyopathy is defined as Heart failure in patients with Type 2 Diabetes (T2DM) in absence of traditional risk factors. Following HTX, a substantial number of recipients develop insulin resistance or T2DM, associated with cardiac allograft vasculopathy and with increased mortality. Recently we have shown that endomyocardial biopsies of heart transplant (HTX) recipients with T2DM express reduced mitochondrial respiration. Purpose The current study analyses time depended impact of T2DM on myocardial mitochondrial respiration of a priorly non-diabetic heart. We hypothesized that myocardial mitochondrial oxidative phosphorylation capacity declines in patients with T2DM compared to glucose tolerant heart transplant recipients and that reduced mitochondrial respiration leads to impairment of cardiac function. Methods We included 101 HTX recipients who underwent routine endomyocardial biopsy. Patients with T1DM or a Donor with DM were excluded. Patients were classified according to criteria of the American Diabetes Association as non-diabetic (n=23), prediabetic (n=38) or T2DM (n=40), by either Fasting Plasma Glucose, 2h Plasma Glucose, HbA1c or intake of antidiabetic medication. We performed ex vivo high resolution respirometry on permeabilized fibres to assess myocardial mitochondrial respiration. Left ventricular ejection fraction (LV-EF) was assessed by cardiac-MRI or Echocardiography. Results Groups were of comparable age (p=0.06), sex (p=0.25) and time since HTX (p=0.91). Mean time since HTX was 29 months. Current rejection episodes (p=0.37) or corticoid pulse therapy (p=0.46) did not significantly differ between groups. Linear regression in T2DM patients revealed an inverse relationship between time since HTX and mitochondrial respiration at state III conditions supported by the substrates octanoyl-carnitine and ADP (R2=0.16, F(1,38)=6.97, p=0.01). Regression analyses for non-DM group and Prediabetes group revealed no significant relationship between time since HTX and mitochondrial function (non-DM: R2=0.04, F(1,21)=0.9, p=0.35; Prediabetes: R2=0.01, F(1,36)=0.27, p=0.61). Exclusion of patients with cellular allograft rejection (ISHLT ≥1) or of patients with recent corticoid pulse therapy did not alter these results. Linear correlation revealed a significant relationship (r=0.33, p=0.04) between declining mitochondrial state III respiration and left ventricular ejection fraction (n=39), suggesting associated functional consequences. Conclusions Our results suggest a T2DM associated decline of mitochondrial oxidative capacity in HTX recipients. Reduced mitochondrial respiration is associated to lower LV-EF. Targeting mitochondrial respiration might be a promising novel therapeutic approach to address T2DM associated mortality. Funding Acknowledgement Type of funding sources: Public grant(s) – National budget only. Main funding source(s): German Research Counsil

ObjectiveTo evaluate the impact of severe tricuspid valve insufficiency (TVI) at the time of left ventricular assist device (LVAD) implantation on the hemodynamic and LVAD parameters in an acute ovine model.MethodsStable heart failure (HF) was induced in 10 ovines through the application of 3 ± 1 coronary ligations. Once stable HF was obtained (after 15 ± 5 days), the animals were supported with an LVAD. Hemodynamic data and pump parameters were obtained and compared in 2 settings; first with LVAD in place after weaning from the cardiopulmonary bypass machine (no TVI condition) and second following the induction of severe TVI through resection of the tricuspid valve (TVI condition).ResultsThere were no statistically significant differences in the hemodynamic and pump parameters between TVI condition and no TVI conditions except for lower cardiac output in the TVI condition (2 [1.38-2.8] L/min vs 3.2 [1.55-3.7] L/min, P = .027) and the expected greater central venous pressure in the TVI condition (26 [24-31] mm Hg vs 15 [13-25] mm Hg, P = .020). A median pump flow of 2.8 (2.45-3.75) L/min versus 2.9 (2.75-3.8) L/min in the TVI condition and no TVI condition was documented (P = .160).ConclusionsResults from this acute animal study suggest that severe TVI in HF with preserved right ventricular function does not have significant impact on the LVAD pump parameters. The observed reduction in cardiac output may warrant further investigations, especially under loading conditions.