Current challenges in cell and gene therapy: a joint view from the European Committee of the International Society for Cell & Gene Therapy (ISCT) and the European Society for Blood and Marrow Transplantation (EBMT)

Cell and gene therapy poses evolving challenges. The current article summarizes the discussions held by European Regional Committee of the International Society for Cell & Gene Therapy and the European Society for Blood and Marrow Transplantation (EBMT) on the current challenges in this field, focusing on the European setting. This article emphasizes the imperative assessment of real-world cell and gene therapy activity, advocating for expanded registries beyond hematopoietic transplantation and chimeric antigen receptor-T-cell therapy. Accreditation's role in ensuring standardized procedures, as exemplified by JACIE (The Joint Accreditation Committee of ISCT-Europe and EBMT), is crucial for safety. Access to commercial products and reimbursement variations among countries underscore the need for uniform access to advanced therapy medical products (ATMPs). Academic product development and point-of-care manufacturing face barriers to patient access. Hospital Exemption's potential, demonstrated by some initial experiences, may increase patient accessibility in individual situations. Regulatory challenges, including the ongoing European ATMPs legislation review, necessitate standardized criteria for Hospital Exemption and mandatory reporting within registries. Efforts to combat unproven therapies and fraud involve collaboration between scientific societies, regulatory bodies and patient groups. Finally, is important to highlight the vital role of education and workforce development in meeting the escalating demand for specialized professionals in the ATMP field. Collaboration among scientific societies, academic institutions, industry, regulatory bodies and patient groups is crucial for overcoming all these challenges to increase gene and cell therapy activity in Europe.

Beneficial Effects of IABP in Anterior Myocardial Infarction Complicated by Cardiogenic Shock

Background and Objectives. Recent guidelines have downgraded the routine use of the intra-aortic balloon pump (IABP) in patients with cardiogenic shock (CS) due to ST-elevation myocardial infarction (STEMI). Despite this, its use in clinical practice remains high. The aim of this study was to evaluate the prognostic impact of the IABP in patients with STEMI complicated by CS undergoing primary PCI (pPCI), focusing on patients with anterior MI in whom a major benefit has been previously hypothesized. Materials and Methods. We enrolled 2958 consecutive patients undergoing pPCI for STEMI in our department from 2005 to 2018. Propensity score matching and mortality analysis were performed. Results. CS occurred in 246 patients (8.3%); among these patients, 145 (60%) had anterior AMI. In the propensity-matched analysis, the use of the IABP was associated with a lower 30-day mortality (39.3% vs. 60.9%, p = 0.032) in the subgroup of patients with anterior STEMI. Conversely, in the whole group of CS patients and in the subgroup of patients with non-anterior STEMI, IABP use did not have a significant impact on mortality. Conclusions. The use of the IABP in cases of STEMI complicated by CS was found to improve survival in patients with anterior infarction. Prospective studies are needed before abandoning or markedly limiting the use of the IABP in this clinical setting.

Cell and gene therapy workforce development: the role of the International Society for Cell & Gene Therapy (ISCT) in the creation of a sustainable and skilled workforce in Europe

The development and production of cell gene and tissue (CGT)-based therapies requires a specialized workforce. Entering the CGT arena is complex because it involves different scientific and biomedical aspects (e.g., immunology, stem cell biology and transplantation), as well as knowledge of regulatory affairs and compliance with pharmaceutical quality standards. Currently, both industry and academia are facing a worldwide workforce shortage, whereas only a handful of educational and training initiatives specifically address the peculiarities of CGT product development, the procurement of substances of human origin, the manufacturing process itself and clinical monitoring and biovigilance. The training offered by traditional Master's and PhD programs is not suited for training a skilled workforce ready to enter the increasingly fast-growing CGT field. Indeed, typically these programs are of long duration and only partially cover the required competencies, whereas the demand for a specialized workforce relentlessly increases. In this paper, we (i) present and discuss our understanding of the roots of current growth acceleration of the CGT field; (ii) anticipate future workforce needs due to the expected increase of marketed CGT-based therapies and (iii) evaluate potential solutions that seek to adapt, develop and implement current educational and training initiatives. Importantly for these solutions, we call for scientific societies, such as the International Society for Cell & Gene Therapy, to play a more active role and act as catalysers for new initiatives, building bridges between academia and Industry to establish effective educational and training programs that will engage and prepare a new generation of qualified professionals for entry into the CGT field.

Gene- and variant-specific efficacy of serum/glucocorticoid-regulated kinase 1 inhibition in long QT syndrome types 1 and 2

AIMS

Current long QT syndrome (LQTS) therapy, largely based on beta-blockade, does not prevent arrhythmias in all patients; therefore, novel therapies are warranted. Pharmacological inhibition of the serum/glucocorticoid-regulated kinase 1 (SGK1-Inh) has been shown to shorten action potential duration (APD) in LQTS type 3. We aimed to investigate whether SGK1-Inh could similarly shorten APD in LQTS types 1 and 2.

METHODS AND RESULTS

Human-induced pluripotent stem cell-derived cardiomyocytes (hiPSC-CMs) and hiPSC-cardiac cell sheets (CCS) were obtained from LQT1 and LQT2 patients; CMs were isolated from transgenic LQT1, LQT2, and wild-type (WT) rabbits. Serum/glucocorticoid-regulated kinase 1 inhibition effects (300 nM-10 µM) on field potential durations (FPD) were investigated in hiPSC-CMs with multielectrode arrays; optical mapping was performed in LQT2 CCS. Whole-cell and perforated patch clamp recordings were performed in isolated LQT1, LQT2, and WT rabbit CMs to investigate SGK1-Inh (3 µM) effects on APD. In all LQT2 models across different species (hiPSC-CMs, hiPSC-CCS, and rabbit CMs) and independent of the disease-causing variant (KCNH2-p.A561V/p.A614V/p.G628S/IVS9-28A/G), SGK1-Inh dose-dependently shortened FPD/APD at 0.3-10 µM (by 20-32%/25-30%/44-45%). Importantly, in LQT2 rabbit CMs, 3 µM SGK1-Inh normalized APD to its WT value. A significant FPD shortening was observed in KCNQ1-p.R594Q hiPSC-CMs at 1/3/10 µM (by 19/26/35%) and in KCNQ1-p.A341V hiPSC-CMs at 10 µM (by 29%). No SGK1-Inh-induced FPD/APD shortening effect was observed in LQT1 KCNQ1-p.A341V hiPSC-CMs or KCNQ1-p.Y315S rabbit CMs at 0.3-3 µM.

CONCLUSION

A robust SGK1-Inh-induced APD shortening was observed across different LQT2 models, species, and genetic variants but less consistently in LQT1 models. This suggests a genotype- and variant-specific beneficial effect of this novel therapeutic approach in LQTS.

From novel discovery tools and biomarkers to precision medicine-basic cardiovascular science highlights of 2021/22

Here, we review the highlights of cardiovascular basic science published in 2021 and early 2022 on behalf of the European Society of Cardiology Council for Basic Cardiovascular Science. We begin with non-coding RNAs which have emerged as central regulators cardiovascular biology, and then discuss how technological developments in single-cell 'omics are providing new insights into cardiovascular development, inflammation, and disease. We also review recent discoveries on the biology of extracellular vesicles in driving either protective or pathogenic responses. The Nobel Prize in Physiology or Medicine 2021 recognized the importance of the molecular basis of mechanosensing and here we review breakthroughs in cardiovascular sensing of mechanical force. We also summarize discoveries in the field of atherosclerosis including the role of clonal haematopoiesis of indeterminate potential, and new mechanisms of crosstalk between hyperglycaemia, lipid mediators, and inflammation. The past 12 months also witnessed major advances in the field of cardiac arrhythmia including new mechanisms of fibrillation. We also focus on inducible pluripotent stem cell technology which has demonstrated disease causality for several genetic polymorphisms in long-QT syndrome and aortic valve disease, paving the way for personalized medicine approaches. Finally, the cardiovascular community has continued to better understand COVID-19 with significant advancement in our knowledge of cardiovascular tropism, molecular markers, the mechanism of vaccine-induced thrombotic complications and new anti-viral therapies that protect the cardiovascular system.

Long COVID and the cardiovascular system - elucidating causes and cellular mechanisms in order to develop targeted diagnostic and therapeutic strategies: A joint Scientific Statement of the ESC Working Groups on Cellular Biology of the Heart and Myocardial & Pericardial Diseases

Long COVID has become a world-wide, non-communicable epidemic, caused by long-lasting multi-organ symptoms that endure for weeks or months after SARS-CoV-2 infection has already subsided. This scientific document aims to provide insight into the possible causes and therapeutic options available for the cardiovascular manifestations of long COVID. In addition to chronic fatigue, which is a common symptom of long COVID, patients may present with chest pain, ECG abnormalities, postural orthostatic tachycardia, or newly developed supraventricular or ventricular arrhythmias. Imaging of the heart and vessels has provided evidence of chronic, post-infectious peri-myocarditis with consequent left or right ventricular failure, arterial wall inflammation or micro-thrombosis in certain patient populations. Better understanding of the underlying cellular and molecular mechanisms of long COVID will aid in the development of effective treatment strategies for its cardiovascular manifestations. A number of mechanisms have been proposed, including those involving direct effects on the myocardium, micro-thrombotic damage to vessels or endothelium, or persistent inflammation. Unfortunately, existing circulating biomarkers, coagulation and inflammatory markers, are not highly predictive for either the presence or outcome of long COVID when measured 3 months after SARS-CoV-2 infection. Further studies are needed to understand underlying mechanisms, identify specific biomarkers and guide future preventive strategies or treatments to address long COVID and its cardiovascular sequelae.

Machine learning for prediction of in-hospital mortality in coronavirus disease 2019 patients: results from an Italian multicenter study

BACKGROUND

Several risk factors have been identified to predict worse outcomes in patients affected by SARS-CoV-2 infection. Machine learning algorithms represent a novel approach to identifying a prediction model with a good discriminatory capacity to be easily used in clinical practice. The aim of this study was to obtain a risk score for in-hospital mortality in patients with coronavirus disease infection (COVID-19) based on a limited number of features collected at hospital admission.

METHODS AND RESULTS

We studied an Italian cohort of consecutive adult Caucasian patients with laboratory-confirmed COVID-19 who were hospitalized in 13 cardiology units during Spring 2020. The Lasso procedure was used to select the most relevant covariates. The dataset was randomly divided into a training set containing 80% of the data, used for estimating the model, and a test set with the remaining 20%. A Random Forest modeled in-hospital mortality with the selected set of covariates: its accuracy was measured by means of the ROC curve, obtaining AUC, sensitivity, specificity and related 95% confidence interval (CI). This model was then compared with the one obtained by the Gradient Boosting Machine (GBM) and with logistic regression. Finally, to understand if each model has the same performance in the training and test set, the two AUCs were compared using the DeLong's test. Among 701 patients enrolled (mean age 67.2 ± 13.2 years, 69.5% male individuals), 165 (23.5%) died during a median hospitalization of 15 (IQR, 9-24) days. Variables selected by the Lasso procedure were: age, oxygen saturation, PaO2/FiO2, creatinine clearance and elevated troponin. Compared with those who survived, deceased patients were older, had a lower blood oxygenation, lower creatinine clearance levels and higher prevalence of elevated troponin (all P < 0.001). The best performance out of the samples was provided by Random Forest with an AUC of 0.78 (95% CI: 0.68-0.88) and a sensitivity of 0.88 (95% CI: 0.58-1.00). Moreover, Random Forest was the unique model that provided similar performance in sample and out of sample (DeLong test P = 0.78).

CONCLUSION

In a large COVID-19 population, we showed that a customizable machine learning-based score derived from clinical variables is feasible and effective for the prediction of in-hospital mortality.

Barriers associated with emergency medical service activation in patients with ST-segment elevation acute coronary syndromes

Many ST-segment elevation acute coronary syndrome (STEACS) patients fail to activate the Emergency Medical System (EMS), with possible dramatic consequences. Prior studies focusing on barriers to EMS activation included patients with any acute coronary syndrome (ACS) without representation of southern European populations. We aimed to investigate the barriers to EMS call for patients diagnosed for STEACS in Italy. A prospective, single-center, survey administered to all patients treated with primary percutaneous coronary intervention for STEACS in a tertiary hospital in northern Italy from 01/06/2018 to 31/05/2020. The questionnaire was filled out by 293 patients. Of these, 191 (65.2%) activated the EMS after symptoms onset. The main reasons for failing to contact EMS were the perception that the symptoms were unrelated to an important health problem (45.5%) and that a private vehicle is faster than EMS to reach the hospital (34.7%). Patients who called a private doctor after symptoms onset did not call EMS more frequently than those who did not and 30% of the patients who did not call the EMS would still act in the same way if a new episode occurred. Previous history of cardiovascular disease was the only predictor of EMS call. Information campaigns are urgently needed to increase EMS activation in case of suspected STEACS and should be primary focused on patients without cardiovascular history, on the misperception that a private vehicle is faster than EMS activation, and on the fact that cardiac arrest occurs early and may be prevented by EMS activation.

P182 VALSARTAN LIMITS PULMONARY AND CARDIAC DAMAGE INDUCED BY SARS–COV–2 IN EXPERIMENTAL MODELS BY REDUCING THE EXPRESSION OF ACE2

Background

SARS–CoV–2 primarily affects the respiratory system, but cardiac complications also occur very often. The entry of SARS–CoV–2 into host cells is mediated by the interaction between the viral glycoprotein Spike (S) and the host angiotensin–converting enzyme 2 (ACE2) protein. The use of ACE inhibitors (ACEIs) and angiotensin II type 1 receptor blockers (ARBs) might influence both ACE2 expression and viral infection, but our knowledge about these possible interactions is limited. Aim. To evaluate the effects of ACEIs and ARBs during active viraemia.

Methods

We tested the effects of exposure to the ACEI Lisinopril (100nM and 500nM) and the ARB Valsartan (10µM and 50µM) on three different cell types: green monkey–derived epithelial cells (VERO E6) which are used to replicate SARS–CoV–2, cardiomyocytes derived from hiPSC (iPSC–CMs) as heart model and a lung epithelial cancer cell line (16HBE) as pulmonary model. The SARS–CoV–2 wild strain was inoculated on cell lines for 1 hour. Cell viability was measured 72 hours after infection. The supernatants of the infected cells were collected and titrated by the micro–neutralization assay on VERO E6 cells to verify the presence of the virus. Levels of ACE2 mRNA and protein content on cell lysates were quantified after each treatment by RT–qPCR and western blot, respectively.

Results

ACEI and ARB at both concentrations do not affect the viability of the 3 cell lines. Vice versa, viral infection significantly decreases the viability of VERO E6 (–60%, p < 0.0001) and iPSC–CMs (–44%, p < 0.001), while 16HBE cells do not show a cytopathic effect after infection. Viral titration shows that SARS–CoV–2 replicated in cell lines and was actively released into supernatants. Valsartan 50µM decreased virus release in the three cell lines and increased the viability of VERO E6 (+69%, p < 0.01) and iPSC–CMs (+20.5%, p < 0.05) after the infection. Valsartan 50µM also decreases both mRNA (–65% in VERO E6, p < 0.001; –50% in iPSC–CMs, p < 0.05; –60.5% in 16HBE, p < 0.01) and protein levels of ACE2 in all 3 cell lines.

Conclusion

The data suggest that ACEIs and ARBs do not worsen the SARS–CoV–2 infection and that Valsartan, by reducing the levels of ACE2 expression, might result protective.

Sex-related differences in patients with coronavirus disease 2019: results of the Cardio-COVID-Italy multicentre study

INTRODUCTION

The role of sex compared to comorbidities and other prognostic variables in patients with coronavirus disease (COVID-19) is unclear.

METHODS

This is a retrospective observational study on patients with COVID-19 infection, referred to 13 cardiology units. The primary objective was to assess the difference in risk of death between the sexes. The secondary objective was to explore sex-based heterogeneity in the association between demographic, clinical and laboratory variables, and patients' risk of death.

RESULTS

Seven hundred and one patients were included: 214 (30.5%) women and 487 (69.5%) men. During a median follow-up of 15 days, deaths occurred in 39 (18.2%) women and 126 (25.9%) men. In a multivariable Cox regression model, men had a nonsignificantly higher risk of death vs. women (P = 0.07).The risk of death was more than double in men with a low lymphocytes count as compared with men with a high lymphocytes count [overall survival hazard ratio (OS-HR) 2.56, 95% confidence interval (CI) 1.72-3.81]. In contrast, lymphocytes count was not related to death in women (P = 0.03).Platelets count was associated with better outcome in men (OS-HR for increase of 50 × 103 units: 0.88 95% CI 0.78-1.00) but not in women. The strength of association between higher PaO2/FiO2 ratio and lower risk of death was larger in women (OS-HR for increase of 50 mmHg/%: 0.72, 95% CI 0.59-0.89) vs. men (OS-HR: 0.88, 95% CI 0.80-0.98; P = 0.05).

CONCLUSIONS

Patients' sex is a relevant variable that should be taken into account when evaluating risk of death from COVID-19. There is a sex-based heterogeneity in the association between baseline variables and patients' risk of death.

Combined Role of Troponin and Natriuretic Peptides Measurements in Patients With Covid-19 (from the Cardio-COVID-Italy Multicenter Study)

Data concerning the combined prognostic role of natriuretic peptide (NP) and troponin in patients with COVID-19 are lacking. The aim of the study is to evaluate the combined prognostic value of NPs and troponin in hospitalized COVID-19 patients. From March 1, 2020 to April 9, 2020, consecutive patients with COVID-19 and available data on cardiac biomarkers at admission were recruited. Patients admitted for acute coronary syndrome were excluded. Troponin levels were defined as elevated when greater than the 99^th percentile of normal values. NPs were considered elevated if above the limit for ruling in acute heart failure (HF). A total of 341 patients were included in this study, mean age 68 ± 13 years, 72% were men. During a median follow-up period of 14 days, 81 patients (24%) died. In the Cox regression analysis, patients with elevated both NPs and troponin levels had higher risk of death compared with those with normal levels of both (hazard ratio 2.94; 95% confidence interval 1.31 to 6.64; p = 0.009), and this remained significant after adjustment for age, gender, oxygen saturation, HF history, and chronic kidney disease. Interestingly, NPs provided risk stratification also in patients with normal troponin values (hazard ratio 2.86; 95% confidence interval 1.21 to 6.72; p = 0.016 with high NPs levels). These data show the combined prognostic role of troponin and NPs in COVID-19 patients. NPs value may be helpful in identifying patients with a worse prognosis among those with normal troponin values. Further, NPs’ cut-point used for diagnosis of acute HF has a predictive role in patients with COVID-19.

Use of hiPSC-Derived Cardiomyocytes to Rule Out Proarrhythmic Effects of Drugs: The Case of Hydroxychloroquine in COVID-19

In the early phases of the COVID-19 pandemic, drug repurposing was widely used to identify compounds that could improve the prognosis of symptomatic patients infected by SARS-CoV-2. Hydroxychloroquine (HCQ) was one of the first drugs used to treat COVID-19 due to its supposed capacity of inhibiting SARS-CoV-2 infection and replication in vitro. While its efficacy is debated, HCQ has been associated with QT interval prolongation and potentially Torsades de Pointes, especially in patients predisposed to developing drug-induced Long QT Syndrome (LQTS) as silent carriers of variants associated with congenital LQTS. If confirmed, these effects represent a limitation to the at-home use of HCQ for COVID-19 infection as adequate ECG monitoring is challenging. We investigated the proarrhythmic profile of HCQ with Multi-Electrode Arrays after exposure of human induced pluripotent stem cell-derived cardiomyocytes (hiPSC-CMs) from two healthy donors, one asymptomatic and two symptomatic LQTS patients. We demonstrated that: I) HCQ induced a concentration-dependent Field Potential Duration (FPD) prolongation and halted the beating at high concentration due to the combined effect of HCQ on multiple ion currents. II) hiPSC-CMs from healthy or asymptomatic carriers tolerated higher concentrations of HCQ and showed lower susceptibility to HCQ-induced electrical abnormalities regardless of baseline FPD. These findings agree with the clinical safety records of HCQ and demonstrated that hiPSC-CMs potentially discriminates symptomatic vs. asymptomatic mutation carriers through pharmacological interventions. Disease-specific cohorts of hiPSC-CMs may be a valid preliminary addition to assess drug safety in vulnerable populations, offering rapid preclinical results with valuable translational relevance for precision medicine.

554 Machine learning for prediction of in-hospital mortality in COVID-19 patients: results from an Italian multicentre study

Aims

Several risk factors have been identified to predict worse outcomes in patients affected by SARS-CoV-2 infection. Prediction models are needed to optimize clinical management and to early stratify patients at a higher mortality risk. Machine learning (ML) algorithms represent a novel approach to identify a prediction model with a good discriminatory capacity to be easily used in clinical practice.

Methods and results

The Cardio-COVID is a multicentre observational study that involved a cohort of consecutive adult Caucasian patients with laboratory-confirmed COVID-19 [by real time reverse transcriptase—polymerase chain reaction (RT-PCR)] who were hospitalized in 13 Italian cardiology units from 1 March to 9 April 2020. Patients were followed-up after the COVID-19 diagnosis and all causes in-hospital mortality or discharge were ascertained until 23 April 2020. Variables with more than 20% of missing values were excluded. The Lasso procedure was used with a λ = 0.07 for reducing the covariates number. Mortality was estimated by means of a Random Forest (RF). The dataset was randomly divided in two subsamples with the same percentage of death/alive people of the entire sample: training set contained 80% of the data and test set the remaining 20%. The training set was used in the calibration procedure where a RF models in-hospital mortality with the covariates selected by Lasso. Its accuracy was measured by means of the ROC curve, obtaining AUC, sensitivity, specificity, and related 95% confidence interval (CI) computed with 10 000 stratified bootstrap replicates. From the RF the relative Variable Importance Measure (relVIM) was extracted to understand which of the selected variables had the greatest impact on outcome, providing a ranking from the most (relVIM = 100) to the less important variable. The model obtained was compared with the Gradient Boosting Machine (GBM) and with the logistic regression, where the predictions were cross validated. Finally, to understand if each model has the same performance in sample (training) and out of sample (test), the two AUCs were compared by means of the DeLong’s test. Among 701 patients enrolled (mean age 67.2 ± 13.2 years, 69.5% males), 165 (23.5%) died during a median hospitalization of 15 (IQR, 9–24) days. Variables selected by the Lasso were: age, Oxygen saturation, PaO2/FiO2, Creatinine Clearance and elevated Troponin. Compared with those who survived, deceased patients were older, had a lower blood oxygenation, a lower creatinine clearance levels and higher prevalence of elevated Troponin (all P &lt; 0.001). Training set included 561 patients and test set 140 patients. The best performance out of sample was provided by the RF with an AUC of 0.78 (95% CI: 0.68–0.88) and a sensitivity of 0.88 (95% CI: 0.58–1.00). Moreover, RF is the unique methodology that provided similar performance in sample and out of sample (DeLong test P = 0.78). On the contrary, prediction model was less accurate by using GBM and logistic regression. The relVIM ranked the variables from the most to the less important in predicting the outcome as follows: clearance creatinine, PaO2/FiO2, age, oxygen saturation, and elevated Troponin.

Conclusions

In a large COVID-19 population, we showed that a customizable ML-based score derived from clinical variables, is feasible and effective for the prediction of in-hospital mortality.

Extracellular vesicles fail to trigger the generation of new cardiomyocytes in chronically infarcted hearts

Background: Extracellular vesicles (EV) mediate the therapeutic effects of stem cells but it is unclear whether this involves cardiac regeneration mediated by endogenous cardiomyocyte proliferation. Methods: Bi-transgenic MerCreMer/ZEG (n = 15/group) and Mosaic Analysis With Double Markers (MADM; n = 6/group) mouse models underwent permanent coronary artery ligation and received, 3 weeks later, 10 billion EV (from human iPS-derived cardiovascular progenitor cells [CPC]), or saline, injected percutaneously under echo guidance in the peri-infarcted myocardium. Endogenous cardiomyocyte proliferation was tracked by EdU labeling and biphoton microscopy. Other end points, including cardiac function (echocardiography and MRI), histology and transcriptomics were blindly assessed 4-6 weeks after injections. Results: There was no proliferation of cardiomyocytes in either transgenic mouse strains. Nevertheless, EV improved cardiac function in both models. In MerCreMer/ZEG mice, LVEF increased by 18.3 ± 0.2% between baseline and the end-study time point in EV-treated hearts which contrasted with a decrease by 2.3 ± 0.2% in the PBS group; MADM mice featured a similar pattern as intra-myocardial administration of EV improved LVEF by 13.3 ± 0.16% from baseline whereas it decreased by 14.4 ± 0.16% in the control PBS-injected group. This functional improvement was confirmed by MRI and associated with a reduction in infarct size, the decreased expression of several pro-fibrotic genes and an overexpression of the anti-fibrotic miRNA 133-a1 compared to controls. Experiments with an anti-miR133-a demonstrated that the cardio-reparative effects of EV were partly abrogated. Conclusions: EV-CPC do not trigger cardiomyocyte proliferation but still improve cardiac function by other mechanisms which may include the regulation of fibrosis.

Clinical utility of the academic research consortium new proposed criteria for high bleeding risk definition in patients with acute coronary syndromes

Background

The Academic Research Consortium High Bleeding Risk (ARC-HBR) criteria have been proposed to stratify the bleeding risk of patients undergoing percutaneous coronary intervention (PCI). While most criteria were established, 4 criteria have been proposed on a de novo basis.

Purpose

We assessed the prevalence and prognosis of new ARC-HBR criteria in a contemporary, prospective, multicenter, quality-improvement registry of all-comers patients with acute coronary syndromes.

Methods

Between 2016 and 2020, consecutive subjects were enrolled; baseline characteristics and medications were prospectively collected, and patients were followed-up at 1 year. All clinical events (including bleeding) were adjudicated by an independent committee. All 17 ARC-HBR criteria were individually evaluated by reviewing patients' charts.

Results

Of the 2804 patients enrolled, 782 (28.0%) met the ARC-HBR definition and 47 (6%) of them experienced a major BARC 3 or 5) bleeding at 1-year. HBR patients had a significantly higher risk of BARC 3–5 bleedings (HR for: 3.07; 95% CI: 2.02–4.67; p&lt;0.0001; Fig. 1A), BARC 2–5 (HR: 1.845; 95% CI: 1.4–2.42; p&lt;0.0001). Fig. 1B indicates the proportion of patients meeting each criterion. Age, (moderate or severe) chronic kidney disease, (moderate or severe) anemia and oral anticoagulant therapy included 88% of HBR patients.

The 4 new ARC-HBR criteria, all together, were present in only 1.7% of our population: 1.0% was planned for major surgery while on dual antiplatelet therapy, 0.5% had a recent intracranial hemorrhage/ictus or brain arteriovenous malformations, 0.1% had hepatic cirrhosis with portal hypertension and 0.1% had a recent surgery or trauma. In a multivariable Cox regression analysis including individual ARC-HBR criteria, only CKD (major and minor criteria), anemia (major and minor criteria) and cancer were the independent predictors of BARC 3–5 events with a concordance-index for this model of 0.698 (p&lt;0.001). In a second model including only CKD (major criterion), anemia (major criterion), age and oral anticoagulation therapy, all these criteria were independent predictors of BARC 3–5 events with a concordance index of 0.674 (pmodel&lt;0.001 for the model) (Fig. 2).

Conclusion

Almost one third of contemporary ACS patients was at HBR according to the ARC-HBR definition and these patients presented a significantly higher risk of bleedings at 1-year. The most common 4 criteria (age, CKD, anemia, and oral anticoagulant therapy) allowed the identification of 88% of HBR patients. The newly proposed HBR criteria were extremely rare and therefore challenging to validate and of uncertain clinical utility. These data may inform and simplify clinical decision making and provide priority for future directions of HBR definitions.

Funding Acknowledgement

Type of funding sources: None. Figure 1Figure 2

Prognostic impact of achieving LDL cholesterol guidelines-recommended target in secondary prevention: a real-world study

Background

Lipid management plays a key role in secondary prevention after acute coronary syndrome. The 2019 European Society of Cardiology guidelines recommend a more ambitious target than the previous guidelines version (i.e., to achieve LDL cholesterol [LDL-C] &lt;55 mg/dL, and to reduce it ≥50% form baseline vs LDL-C&lt;70 mg/dl or reduced ≥50% form baseline). Currently, data on the reduction of cardiovascular events in patients achieving the 2019 goals in a real-world population are missing.

Purpose

The aim of this study was to determine the risk of major adverse cardiovascular events (MACE) during follow-up in post myocardial infarction (PMI) patients according to the achievement of the guidelines-recommended goals in terms of LDL-C reduction.

Methods

We conducted a retrospective analysis of a monocentric observational registry prospectively enrolling patients admitted to our hospital for ST segment elevation myocardial infarction and followed-up in our dedicated PMI ambulatory. The analysis considered the patients enrolled between January 2011 and February 2019. Demographical and clinical data were extracted from a dedicated digital database, and the clinical events occurred during follow-up were obtained by telephone interviews or clinical records. We considered a combined endpoint of MACE defined as all-cause death, non-fatal MI, non-fatal stroke and unplanned revascularization. LDL-C was collected at baseline and at 1, 6 and 12 months after the event. The lower value collected at follow-up was used to define the achievement of the target goals. We conducted a Kaplan-Meier analysis and log-rank test comparing patients who achieved LDL-C &lt;55 mg/dL and ≤50% from baseline (group 2019) vs those with LDL-C &lt;70 mg/dL or ≤50% from baseline (group 2016). Continue variable are presented as median (interquartile range).

Results

A total of 1201 patients (23% female) were included in our analysis. Median age was 63 (54–72) years, 56% had hypertension, 17% diabetes, and 38% were smoker. Baseline LDL-C was 123 (97–148) mg/dL, the median LDL-C at follow-up was 63 (52–78) mg/dL, significantly reduced from baseline (P&lt;0.0001). Between 6 and 12 months 83% of patients were treated with statin therapy alone (73% high intensity), and 17% with the addition of ezetimibe. The 2016 target was achieved in 828 patients (69%), while 270 patients (22.5%) obtained also the 2019 target. Median follow-up was 60 (40–77) months. The net incidence of MACE was 12.9% in group 2019 vs 23.7% in group 2016 (HR 0.61; 95% CI 0.42–0.88; P log-rank=0.0087; Number Needed to Treat=9; see Figure).

Conclusion

Our data from a real-world cohort of PMI patients emphasize the importance of achieving the guideline-recommended secondary prevention goals of LDL-C&lt;55 mg/dl and ≤50% from baseline in order to reduce MACE.

Funding Acknowledgement

Type of funding sources: None.

Barriers associated with emergency medical service activation in Italian patients with ST-segment elevation acute coronary syndromes

Background

Many ST-segment elevation acute coronary syndrome (STEACS) patients fail to activate the Emergency Medical System (EMS), with possible dramatic consequences. Prior studies focusing on barriers to EMS activation include patients with any acute coronary syndrome (ACS) without representation of southern European populations. However, barriers are influenced by the ACS type and by socio-demographic and racial factors.

Purpose

We aimed to investigate the barriers to EMS call for patients diagnosed for STEACS in Italy.

Methods

A prospective, single-center, survey-based study, including all the patients treated with primary percutaneous coronary intervention for STEACS in a tertiary hospital in northern Italy from 1st June 2018 to 31st May 2020.

Results

The questionnaire was filled out by 293 patients. The majority of the participants were males (74%), married (70.4%), with a high-school degree (38.4%) and with a median age of 62 years. Chest pain as a possible symptom related to a cardiovascular attack is known by most of the respondents (89%), and left arm pain/shake by 53.7% of them, whilst the other possible signs and symptoms (i.e. dyspnea, asthenia, sweating, nausea, vomiting, dizziness) were unknown to the majority of the participants. Only 191 (65.2%) of the participants activated the EMS after symptoms onset. The main reasons for not calling EMS were the perception that symptoms were not related to an important health problem (45.5%) and that a private vehicle is faster than EMS to reach the hospital (34.7%). The median time to first medical contact was 60 minutes, and it was significantly higher in the patients who did not called EMS compared to those who did (180 [60–420] mins vs 35 [15–120] mins, p&lt;0.001). The patients who called a private doctor after symptoms onset did not called EMS more frequently than those who did not (5.9% vs 8.2%, p=0.3). Moreover, 30% of the patients who did not call the EMS would still act in the same way if a new episode occurred and the main reasons for this were that they think to be faster than EMS (57.1%) and to live close to the hospital (17.9%). Analyzing predictors of EMS activation, only prior history of cardiovascular disease has been demonstrated to be a predictor of calling the EMS in case of symptoms suspected for STEACS.

Conclusions

Our study, from the southern Europe, showed that a substantial percentage of patients with symptoms suspected for STEACS preferred private vehicle rather than activating the EMS. Our results highlight the need for information campaigns targeted to both the general population and medical doctors, stressing that the EMS is faster than a private vehicle to direct the patient to the right hospital and increasing the awareness of the people on the type of possible heart attack symptoms, which seem to be the most neglected issues by patients who did not call the EMS.

Funding Acknowledgement

Type of funding sources: None.

Estimating the Posttest Probability of Long QT Syndrome Diagnosis for Rare KCNH2 Variants

BACKGROUND

The proliferation of genetic profiling has revealed many associations between genetic variations and disease. However, large-scale phenotyping efforts in largely healthy populations, coupled with DNA sequencing, suggest variants currently annotated as pathogenic are more common in healthy populations than previously thought. In addition, novel and rare variants are frequently observed in genes associated with disease both in healthy individuals and those under suspicion of disease. This raises the question of whether these variants can be useful predictors of disease. To answer this question, we assessed the degree to which the presence of a variant in the cardiac potassium channel gene KCNH2 was diagnostically predictive for the autosomal dominant long QT syndrome.

METHODS

We estimated the probability of a long QT diagnosis given the presence of each KCNH2 variant using Bayesian methods that incorporated variant features such as changes in variant function, protein structure, and in silico predictions. We call this estimate the posttest probability of disease. Our method was applied to over 4000 individuals heterozygous for 871 missense or in-frame insertion/deletion variants in KCNH2 and validated against a separate international cohort of 933 individuals heterozygous for 266 missense or in-frame insertion/deletion variants.

RESULTS

Our method was well-calibrated for the observed fraction of heterozygotes diagnosed with long QT syndrome. Heuristically, we found that the innate diagnostic information one learns about a variant from 3-dimensional variant location, in vitro functional data, and in silico predictors is equivalent to the diagnostic information one learns about that same variant by clinically phenotyping 10 heterozygotes. Most importantly, these data can be obtained in the absence of any clinical observations.

CONCLUSIONS

We show how variant-specific features can inform a prior probability of disease for rare variants even in the absence of clinically phenotyped heterozygotes.

Implications of atrial fibrillation on the clinical course and outcomes of hospitalized COVID-19 patients: results of the Cardio-COVID-Italy multicentre study

AIMS

To assess the clinical relevance of a history of atrial fibrillation (AF) in hospitalized patients with coronavirus disease 2019 (COVID-19).

METHODS AND RESULTS

We enrolled 696 consecutive patients (mean age 67.4 ± 13.2 years, 69.7% males) admitted for COVID-19 in 13 Italian cardiology centres between 1 March and 9 April 2020. One hundred and six patients (15%) had a history of AF and the median hospitalization length was 14 days (interquartile range 9-24). Patients with a history of AF were older and with a higher burden of cardiovascular risk factors. Compared to patients without AF, they showed a higher rate of in-hospital death (38.7% vs. 20.8%; P < 0.001). History of AF was associated with an increased risk of death after adjustment for clinical confounders related to COVID-19 severity and cardiovascular comorbidities, including history of heart failure (HF) and increased plasma troponin [adjusted hazard ratio (HR): 1.73; 95% confidence interval (CI) 1.06-2.84; P = 0.029]. Patients with a history of AF also had more in-hospital clinical events including new-onset AF (36.8% vs. 7.9%; P < 0.001), acute HF (25.3% vs. 6.3%; P < 0.001), and multiorgan failure (13.9% vs. 5.8%; P = 0.010). The association between AF and worse outcome was not modified by previous or concomitant use of anticoagulants or steroid therapy (P for interaction >0.05 for both) and was not related to stroke or bleeding events.

CONCLUSION

Among hospitalized patients with COVID-19, a history of AF contributes to worse clinical course with a higher mortality and in-hospital events including new-onset AF, acute HF, and multiorgan failure. The mortality risk remains significant after adjustment for variables associated with COVID-19 severity and comorbidities.

The prognostic value of serial troponin measurements in patients admitted for COVID-19

Aims

Myocardial injury (MI) in coronavirus disease‐19 (COVID‐19) is quite prevalent at admission and affects prognosis. Little is known about troponin trajectories and their prognostic role. We aimed to describe the early in‐hospital evolution of MI and its prognostic impact.

Methods and results

We performed an analysis from an Italian multicentre study enrolling COVID‐19 patients, hospitalized from 1 March to 9 April 2020. MI was defined as increased troponin level. The first troponin was tested within 24 h from admission, the second one between 24 and 48 h. Elevated troponin was defined as values above the 99th percentile of normal values. Patients were divided in four groups: normal, normal then elevated, elevated then normal, and elevated. The outcome was in‐hospital death. The study population included 197 patients; 41% had normal troponin at both evaluations, 44% had elevated troponin at both assessments, 8% had normal then elevated troponin, and 7% had elevated then normal troponin. During hospitalization, 49 (25%) patients died. Patients with incident MI, with persistent MI, and with MI only at admission had a higher risk of death compared with those with normal troponin at both evaluations (P < 0.001). At multivariable analysis, patients with normal troponin at admission and MI injury on Day 2 had the highest mortality risk (hazard ratio 3.78, 95% confidence interval 1.10–13.09, P = 0.035).

Conclusions

In patients admitted for COVID‐19, re‐test MI on Day 2 provides a prognostic value. A non‐negligible proportion of patients with incident MI on Day 2 is identified at high risk of death only by the second measurement.

Pulmonary embolism in patients with COVID-19: characteristics and outcomes in the Cardio-COVID Italy multicenter study

BACKGROUND

Pulmonary embolism (PE) has been described in coronavirus disease 2019 (COVID-19) critically ill patients, but the evidence from more heterogeneous cohorts is limited.

METHODS

Data were retrospectively obtained from consecutive COVID-19 patients admitted to 13 Cardiology Units in Italy, from March 1st to April 9th, 2020, and followed until in-hospital death, discharge, or April 23rd, 2020. The association of baseline variables with computed tomography-confirmed PE was investigated by Cox hazards regression analysis. The relationship between D-dimer levels and PE incidence was evaluated using restricted cubic splines models.

RESULTS

The study included 689 patients (67.3 ± 13.2 year-old, 69.4% males), of whom 43.6% were non-invasively ventilated and 15.8% invasively. 52 (7.5%) had PE over 15 (9-24) days of follow-up. Compared with those without PE, these subjects had younger age, higher BMI, less often heart failure and chronic kidney disease, more severe cardio-pulmonary involvement, and higher admission D-dimer [4344 (1099-15,118) vs. 818.5 (417-1460) ng/mL, p < 0.001]. They also received more frequently darunavir/ritonavir, tocilizumab and ventilation support. Furthermore, they faced more bleeding episodes requiring transfusion (15.6% vs. 5.1%, p < 0.001) and non-significantly higher in-hospital mortality (34.6% vs. 22.9%, p = 0.06). In multivariate regression, only D-dimer was associated with PE (HR 1.72, 95% CI 1.13-2.62; p = 0.01). The relation between D-dimer concentrations and PE incidence was linear, without inflection point. Only two subjects had a baseline D-dimer < 500 ng/mL.

CONCLUSIONS

PE occurs in a sizable proportion of hospitalized COVID-19 patients. The implications of bleeding events and the role of D-dimer in this population need to be clarified.

Elevated serum uric acid is a predictor of contrast associated acute kidney injury in patient with ST-segment elevation myocardial infarction undergoing primary percutaneous coronary intervention

BACKGROUND

Contrast associated-acute kidney injury (CA-AKI) has been associated with adverse outcomes after ST-segment elevation myocardial infarction (STEMI). However, early markers of CA-AKI are still needed to improve risk stratification. We investigated the association between elevated serum uric acid (eSUA) and CA-AKI in patients with STEMI treated with primary percutaneous coronary intervention (pPCI).

METHODS AND RESULTS

Serum creatinine (Scr) was measured at admission and 24, 48 and 72 h after pPCI. CA-AKI was defined as an increase of 25% (CA-AKI 25%) or 0.5 mg/dl (CA-AKI 0.5) of Scr level above the baseline after 48 h following contrast administration. Multivariable analyses to investigate CA-AKI predictors were performed by binary logistic regression and multivariable backward logistic regression model. In the 3023 patients considered, CA-AKI was more frequent among patients with eSUA as compared with patients with normal SUA levels, considering both CA-AKI definitions (CA-AKI25%: 20.8% vs 16.2%, p < 0.012; CA-AKI 0.5: 10.1% vs 5.8%, p < 0.001). The association between eSUA and CA-AKI was confirmed at multivariable analyses (CA-AKI 25%: odd ratio 1.32, 95% CI 1.03-1.69, p = 0.027; CA-AKI 0.5: odd ratio 1.76, 95% CI 1.11-2.79, p = 0.016).

CONCLUSION

Elevated serum uric acid is associated with CA-AKI after reperfusion in patients with STEMI treated with pPCI.

Neutrophil Extracellular Traps Induce the Epithelial-Mesenchymal Transition: Implications in Post-COVID-19 Fibrosis

The release of neutrophil extracellular traps (NETs), a process termed NETosis, avoids pathogen spread but may cause tissue injury. NETs have been found in severe COVID-19 patients, but their role in disease development is still unknown. The aim of this study is to assess the capacity of NETs to drive epithelial-mesenchymal transition (EMT) of lung epithelial cells and to analyze the involvement of NETs in COVID-19. Bronchoalveolar lavage fluid of severe COVID-19 patients showed high concentration of NETs that correlates with neutrophils count; moreover, the analysis of lung tissues of COVID-19 deceased patients showed a subset of alveolar reactive pneumocytes with a co-expression of epithelial marker and a mesenchymal marker, confirming the induction of EMT mechanism after severe SARS-CoV2 infection. By airway in vitro models, cultivating A549 or 16HBE at air-liquid interface, adding alveolar macrophages (AM), neutrophils and SARS-CoV2, we demonstrated that to trigger a complete EMT expression pattern are necessary the induction of NETosis by SARS-CoV2 and the secretion of AM factors (TGF-β, IL8 and IL1β). All our results highlight the possible mechanism that can induce lung fibrosis after SARS-CoV2 infection.

Precision Medicine and cardiac channelopathies: when dreams meet reality

Precision Medicine (PM) is an innovative approach that, by relying on large populations’ datasets, patients’ genetics and characteristics, and advanced technologies, aims at improving risk stratification and at identifying patient-specific management through targeted diagnostic and therapeutic strategies. Cardiac channelopathies are being progressively involved in the evolution brought by PM and some of them are benefiting from these novel approaches, especially the long QT syndrome. Here, we have explored the main layers that should be considered when developing a PM approach for cardiac channelopathies, with a focus on modern in vitro strategies based on patient-specific human-induced pluripotent stem cells and on in silico models. PM is where scientists and clinicians must meet and integrate their expertise to improve medical care in an innovative way but without losing common sense. We have indeed tried to provide the cardiologist’s point of view by comparing state-of-the-art techniques and approaches, including revolutionary discoveries, to current practice. This point matters because the new approaches may, or may not, exceed the efficacy and safety of established therapies. Thus, our own eagerness to implement the most recent translational strategies for cardiac channelopathies must be tempered by an objective assessment to verify whether the PM approaches are indeed making a difference for the patients. We believe that PM may shape the diagnosis and treatment of cardiac channelopathies for years to come. Nonetheless, its potential superiority over standard therapies should be constantly monitored and assessed before translating intellectually rewarding new discoveries into clinical practice.

Determinants of the protective effect of glucocorticoids on mortality in hospitalized patients with COVID-19: Insights from the Cardio-COVID-Italy multicenter study

Background

Glucocorticoid therapy has emerged as an effective therapeutic option in hospitalized patients with coronavirus disease 2019 (COVID-19). This study aimed to focus on the impact of relevant clinical and laboratory factors on the protective effect of glucocorticoids on mortality.

Methods

A sub-analysis was performed of the multicenter Cardio-COVID-Italy registry, enrolling consecutive patients with COVID-19 admitted to 13 Italian cardiology units between 01 March 2020 and 09 April 2020. The primary endpoint was in-hospital mortality.

Results

A total of 706 COVID-19 patients were included (349 treated with glucocorticoids, 357 not treated with glucocorticoids). After adjustment for relevant covariates, use of glucocorticoids was associated with a lower risk of in-hospital mortality (adjusted HR 0.44; 95% CI 0.26–0.72; p = 0.001). A significant interaction was observed between the protective effect of glucocorticoids on mortality and PaO₂/FiO₂ ratio on admission (p = 0.042), oxygen saturation on admission (p = 0.017), and peak CRP (0.023). Such protective effects of glucocorticoids were mainly observed in patients with lower PaO₂/FiO₂ ratio (<300), lower oxygen saturation (<90%), and higher CRP (>100 mg/L).

Conclusions

The protective effects of glucocorticoids on mortality in COVID-19 were more evident among patients with worse respiratory parameters and higher systemic inflammation.

Has hyperglycemia a different prognostic role in STEMI patients with or without diabetes?

BACKGROUND AND AIMS

Hyperglycemia at hospital admission is a common finding in patients with STEMI. However, whether elevated acute glycemia in these patients may have a direct impact on worsening prognosis or is just a marker of a greater neurohormonal activation in response to the infarction is still unsettled. We sought to investigate the prognostic impact of hyperglycemia at hospital admission in patients undergoing primary PCI (pPCI) for STEMI, and the influence of the presence of diabetes mellitus (DM) on its prognostic impact.

METHODS

and Results, We enrolled 2958 consecutive STEMI patients treated by pPCI. Hyperglycemia was defined as plasma glucose >198 mg/dL (or >11 mmol/L). Patients with hyperglycemia showed a greater risk-profile; they also experienced a higher mortality both at univariable (17.6% vs 5.2%, p < 0.001) and multivariable (HR 1.9, 95%IC 1.5-2.9, p = 0.001) analysis. However, after stratification for DM presence, hyperglycemia resulted as an independent predictor of mortality only in patients without DM (HR 2, 95%IC 1.2-3.4, p = 0.01).

CONCLUSION

Hyperglycemia in the setting of myocardial infarction treated with primary PCI in an independent predictor of all-cause mortality in patients without diabetes; in patients with diabetes, its prognostic impact seems attenuated.

Elevated serum uric acid is associated with a greater inflammatory response and with short- and long-term mortality in patients with ST-segment elevation myocardial infarction undergoing primary percutaneous coronary intervention

BACKGROUND AND AIMS

Despite elevated serum uric acid (eSUA) has been identified as independent risk factor for cardiovascular diseases, its prognostic value in the setting of ST-segment elevation myocardial infarction (STEMI) is still controversial. Although the mechanisms of this possible relationship are unsettled it has been suggested that eSUA could trigger the inflammatory response. This study sought to investigate the association between eSUA with short- and long-term mortality and with inflammatory response in patients with STEMI treated with primary percutaneous coronary intervention (pPCI).

METHODS AND RESULTS

Blood samples were collected on admission and at 24 and 48 h after pPCI: the inflammatory biomarkers C-reactive protein (CRP), neutrophil count and neutrophil to lymphocytes ratio (NLR) were considered. Baseline eSUA was defined as ≥6.8 mg/dl. Cumulative 30-days and 1-year mortalities were estimated using the Kaplan-Meyer analysis. Multivariable analyses were performed by Cox proportional hazard models. In the 2369 patients with STEMI considered, 30-day mortality was 5.8% among patients with eSUA and 2% among patient with normal SUA level (p < 0.001); 1-year mortality was 8.5% vs 4%, respectively (p < 0.001). At multivariable analyses eSUA was an independent predictor of 30-day mortality (HR 1.196, 95%CI 1.006-1.321, p = 0.042) and 1-year mortality (HR 1.178, 95%CI 1.052-1.320, p = 0.005). eSUA patients presented higher values in on admission CRP (p < 0.001) and in neutrophil count and NLR at 24 h (respectively, p = 0.020 and p < 0.001) and at 48 h (p = 0.018 and p < 0.001) compared to patients with normal SUA levels.

CONCLUSIONS

Elevated serum uric acid is associated with higher short- and long-term mortality and with a greater inflammatory response after reperfusion in patients with STEMI treated with primary PCI.

Human mesenchymal stromal cells do not express ACE2 and TMPRSS2 and are not permissive to SARS-CoV-2 infection

Anti‐inflammatory and immune‐modulatory therapies have been proposed for the treatment of COVID‐19 and its most serious complications. Among others, the use of mesenchymal stromal cells (MSCs) is under investigation given their well‐documented anti‐inflammatory and immunomodulatory properties. However, some critical issues regarding the possibility that MSCs could be infected by the virus have been raised. Angiotensin‐converting enzyme 2 (ACE2) and type II transmembrane serine protease (TMPRSS2) are the main host cell factors for the severe acute respiratory syndrome‐coronavirus 2 (SARS‐CoV‐2), entry, but so far it is unclear if human MSCs do or do not express these two proteins. To elucidate these important aspects, we evaluated if human MSCs from both fetal and adult tissues constitutively express ACE2 and TMPRSS2 and, most importantly, if they can be infected by SARS‐CoV‐2. We evaluated human MSCs derived from amnios, cord blood, cord tissue, adipose tissue, and bone marrow. ACE2 and TMPRSS2 were expressed by the SARS‐CoV‐2‐permissive human pulmonary Calu‐3 cell line but not by all the MSCs tested. MSCs were then exposed to SARS‐CoV‐2 wild strain without evidence of cytopathic effect. Moreover, we also excluded that the MSCs could be infected without showing lytic effects since their conditioned medium after SARS‐CoV‐2 exposure did not contain viral particles. Our data, demonstrating that MSCs derived from different human tissues are not permissive to SARS‐CoV‐2 infection, support the safety of MSCs as potential therapy for COVID‐19.

386 Achieving Ldl Cholesterol Target In A Real-World Secondary Prevention Cohort: When Two Is Better Than One

Aims

Lipid management plays a key role in secondary prevention after acute coronary syndrome. Current European Society of Cardiology guidelines recommend a dual goal: to achieve LDL cholesterol (LDL-C) &lt;55 mg/dL, and to reduce it ≥ 50% form baseline. Currently, data on the reduction of cardiovascular events in patients achieving both goals in a real-world population are missing. Accordingly, the objective of this study was to determine the prognosis in post myocardial infarction (PMI) patients and determine the risk of new events according to the achievement of the optimal goals indicated by the guidelines in terms of LDL-C reduction.

Methods and results

We conducted a retrospective analysis of a monocentric observational registry prospectively enrolling patients admitted to our hospital for ST segment elevation myocardial infarction (STEMI) and followed-up in our dedicated PMI ambulatory. The analysis considered the patients enrolled between 2013 and 2017. Demographical and clinical data were extracted from a dedicated digital database, and the clinical events occurred during follow-up were obtained by telephone interviews or clinical records. We considered a combined endpoint of major adverse cardiovascular events (MACE) of all-cause death, non-fatal MI, non-fatal stroke and unplanned revascularization. LDL-C was collected at baseline and at 1, 6 and 12 months after the event. The lower value collected at follow-up was used to define the achievement of the target goals. We conducted a Kaplan-Meier analysis and log-rank test comparing patients who achieved LDL-C &lt; 55 mg/dL and ≤50% from baseline (group A) vs those with only LDL-C &lt; 55 mg/dL (group B). Continue variable are presented as median (interquartile range). A total of 814 patients (23% female) were included in our analysis. Median age was 63 (55–72) years, 57% had hypertension, 19% diabetes, 36% were smoker and 17% obese. Baseline LDL-C was 124 (97–146) mg/dL, the median LDL-C at follow-up was 63 (52–78) mg/dL, significantly reduced from baseline (P &lt; 0.0001). Between 6 and 12 months 83.3% of patients were treated with statin therapy alone (73% high intensity), 15.3% with the addition of ezetimibe, and 0.5% with ezetimibe alone. LDL-C &lt; 55 mg/dl was achieved in 244 patients (30%), while 175 patients (21%) obtained also LDL-C ≤ 50% from baseline. Median follow-up was 52 (34–66) months. The net incidence of MACE was 12% in group A vs 27.5% in group B (HR 0.35; 95% CI 0.17–0.70; P log-rank = 0.0032; Number Needed to Treat = 6; see Figure).

Conclusion

Our data from a real-world cohort of PMI patients emphasize the importance of achieving both the guideline-recommended secondary prevention goals of LDL-C &lt; 55 mg/dl and ≤50% from baseline in order to reduce MACE.

Association of Troponin Levels With Mortality in Italian Patients Hospitalized With Coronavirus Disease 2019: Results of a Multicenter Study

Importance

Myocardial injury, detected by elevated plasma troponin levels, has been associated with mortality in patients hospitalized with coronavirus disease 2019 (COVID-19). However, the initial data were reported from single-center or 2-center studies in Chinese populations. Compared with these patients, European and US patients are older, with more comorbidities and higher mortality rates.

Objective

To evaluate the prevalence and prognostic value of myocardial injury, detected by elevated plasma troponin levels, in a large population of White Italian patients with COVID-19.

Design, Setting, and Participants

This is a multicenter, cross-sectional study enrolling consecutive patients with laboratory-confirmed COVID-19 who were hospitalized in 13 Italian cardiology units from March 1 to April 9, 2020. Patients admitted for acute coronary syndrome were excluded. Elevated troponin levels were defined as values greater than the 99th percentile of normal values.

Main Outcomes and Measures

Clinical characteristics and outcomes stratified as elevated or normal cardiac troponin levels at admission, defined as troponin T or troponin I at a level greater than the 99th percentile of normal values.

Results

A total of 614 patients with COVID-19 were included in this study (mean age [SD], 67 [13] years; 70.8% male), of whom 148 patients (24.1%) died during the hospitalization. Elevated troponin levels were found in 278 patients (45.3%). These patients were older (mean [SD] age, 64.0 [13.6] years vs 71.3 [12.0] years; P < .001) and had higher prevalence of hypertension (168 patients [50.5%] vs 182 patients [65.9%]; P < .001), heart failure (24 [7.2%]; 63 [22.8%]; P < .001), coronary artery disease (50 [15.0%] vs 87 [31.5%]; P < .001), and atrial fibrillation (33 [9.9%] vs 67 [24.3%]; P < .001). Elevated troponin levels were associated with an increased in-hospital mortality (37% vs 13%; HR, 1.71 [95% CI, 1.13-2.59]; P = .01 via multivariable Cox regression analysis), and this was independent from concomitant cardiac disease. Elevated troponin levels were also associated with a higher risk of in-hospital complications: heart failure (44 patients [19.2%] vs 7 patients [2.9%]; P < .001), sepsis (31 [11.7%] vs 21 [6.4%]; P = .03), acute kidney failure (41 [20.8%] vs 13 [6.2%]; P < .001), multiorgan failure (21 [10.9%] vs 6 [2.9%]; P = .003), pulmonary embolism (27 [9.9%] vs 17 [5.2%]; P = .04), delirium (13 [6.8%] vs 3 [1.5%]; P = .02), and major bleeding (16 [7.0%] vs 4 [1.6%]; P = .008).

Conclusions and Relevance

In this multicenter, cross-sectional study of Italian patients with COVID-19, elevated troponin was an independent variable associated with in-hospital mortality and a greater risk of cardiovascular and noncardiovascular complications during a hospitalization for COVID-19.

Impact of heart failure on the clinical course and outcomes of patients hospitalized for COVID-19. Results of the Cardio-COVID-Italy multicentre study

AIMS

To assess the prognostic value of a history of heart failure (HF) in patients with coronavirus disease 2019 (COVID-19).

METHODS AND RESULTS

We enrolled 692 consecutive patients admitted for COVID-19 in 13 Italian cardiology centres between 1 March and 9 April 2020. Mean age was 67.4 ± 13.2 years, 69.5% of patients were males, 90 (13.0%) had a history of HF, median hospitalization length was 14 days (interquartile range 9-24). In-hospital death occurred in 37 of 90 patients (41.1%) with HF history vs. 126 of those with no HF history (20.9%). The increased risk of death associated with HF history remained significant after adjustment for clinical variables related to COVID-19 and HF severity, including comorbidities, oxygen saturation, lymphocyte count and plasma troponin [adjusted hazard ratio (HR) for death: 2.25; 95% confidence interval (CI) 1.26-4.02; P = 0.006 at multivariable Cox regression model including 404 patients]. Patients with a history of HF also had more in-hospital complications including acute HF (33.3% vs. 5.1%, P < 0.001), acute renal failure (28.1% vs. 12.9%, P < 0.001), multiorgan failure (15.9% vs. 5.8%, P = 0.004) and sepsis (18.4% vs. 8.9%, P = 0.006). Other independent predictors of outcome were age, sex, oxygen saturation and oxygen partial pressure at arterial gas analysis/fraction of inspired oxygen ratio (PaO₂ /FiO₂ ). In-hospital treatment with corticosteroids and heparin had beneficial effects (adjusted HR for death: 0.46; 95% CI 0.29-0.74; P = 0.001; n = 404 for corticosteroids, and adjusted HR 0.41; 95% CI 0.25-0.67; P < 0.001; n = 364 for heparin).

CONCLUSIONS

Hospitalized patients with COVID-19 and a history of HF have an extremely poor outcome with higher mortality and in-hospital complications. HF history is an independent predictor of increased in-hospital mortality.

Cardiac involvement at presentation in patients hospitalized with COVID-19 and their outcome in a tertiary referral hospital in Northern Italy

The correlation between myocardial injury and clinical outcome in COVID-19 patients is gaining attention in the literature. The aim of the present study was to evaluate the role of cardiac involvement and of respiratory failure in a cohort of COVID-19 patients hospitalized in an academic hospital in Lombardy, one of the most affected Italian (and worldwide) regions by the epidemic. The study included 405 consecutive patients with confirmed COVID-19 admitted to a medical ward from February 25th to March 31st, 2020. Follow-up of surviving patients ended either at hospital discharge or by July 30th, 2020. Myocardial injury was defined on the basis of the presence of blood levels of hs-TnI above the 99th percentile upper reference limit. Respiratory function was assessed as PaO₂/FiO₂ (P/F) ratio. The primary end-point was death for any cause. During hospitalization, 124 patients died. Death rate increased from 7.9% in patients with normal hs-TnI plasma levels and no cardiac comorbidity to 61.5% in patients with elevated hs-TnI and cardiac involvement (p < 0.001). At multivariable analysis, older age, P/F ratio < 200 (both p < 0.001) and hs-TnI plasma levels were independent predictors of death. However, it must be emphasized that the median values of hs-TnI were within normal range in non-survivors. Cardiac involvement at presentation was associated with poor prognosis in COVID-19 patients, but, even in a population of COVID-19 patients who did not require invasive ventilation at hospital admission, mortality was mainly driven by older age and respiratory failure.

D-dimer for the prediction of left atrial appendage thrombosis: daydream or reality? A meta-analysis

Introduction

Left atrial appendage thrombosis (LAAT) is a dangerous condition that mainly affects patients with atrial fibrillation (AF) or those with mitral stenosis (MS), increasing their risk of stroke. Transesophageal echocardiography (TEE) is the gold standard for the diagnosis of LAAT but some technical issues and the suboptimal sensitivity in identifying small thrombi, especially within a side lobe, can limit its clinical usefulness. Reliable non-invasive diagnostic methods could be useful in clinical practice. D-dimer, a fibrin degradation product already commonly used in the diagnostic work-up of conditions such as venous thromboembolism, may have a role as a non-invasive marker of LAAT.

Purpose

To evaluate the diagnostic performance of D-dimer for the detection of LAAT in patients with AF and/or MS, using TEE as the reference standard.

Methods

We searched the literature for studies that evaluated the ability of D-dimer to predict LAAT. For each study a 2x2 table of D-dimer positivity and LAAT presence was constructed. Sensitivity, specificity, positive predictive value and negative predictive value were calculated. Considering the different diagnostic thresholds used in the included studies, the overall sensitivity and specificity were calculated using a hierarchal summary receiver operating characteristic (HSROC) model and a SROC curve was generated.

Results

6 studies, evaluating 1380 patients of whom 154 had LAAT, were included in the analysis. The prevalence of LAAT in the studies ranged from 9% to 26%, with a median of 12%. The mean age was 60±13 years, 63% were male. The mean left atrial diameter was 43±3 mm. The D-dimer diagnostic threshold ranged from 200 mcg/l to 1150 mcg/l. The overall sensitivity calculated with the HSROC model was 85%±28% and the overall specificity was 82%±29%. The negative predictive value was 98%. Figure 1 shows the summary ROC curve: individual studies are depicted by a clear circle; the red circle marks the pooled sensitivity and specificity across the 6 studies. The red dot-dashed-curve marks the boundary of the 95% credible region for the pooled estimates of sensitivity and specificity.

Conclusions

Our analysis shows that D-dimer has a good diagnostic performance with a very high negative predictive value for LAAT and therefore it might be of clinical aid for ruling out the presence of LAAT in patients with AF and/or MS. Further studies are needed to determine the best diagnostic threshold.

Figure 1

Funding Acknowledgement

Type of funding source: None

From patient-specific induced pluripotent stem cells to clinical translation in long QT syndrome Type 2

AIMS

Having shown that Lumacaftor rescued the hERG trafficking defect in the induced pluripotent stem cell-derived cardiomyocytes (iPSC-CMs) of two LQT2 patients, we tested whether the commercial association Lumacaftor + Ivacaftor (LUM + IVA) could shorten the QTc in the same two patients.

METHODS AND RESULTS

After hospital admission and 1 day of baseline recordings, half dose LUM + IVA was administered on Day 1, followed by full dose (LUM 800 mg + IVA 500 mg) for 7 days. A continuous 12-lead Holter ECG allowed a large number of blind QTc measurements. Lumacaftor + Ivacaftor shortened QTc significantly in both patients: in V6 from 551 ± 22 ms to 523 ± 35 ms in Patient 1 (Pt1) and from 472 ± 21 ms to 449 ± 20 ms in Patient 2 (Pt2); in DII from 562 ± 25 ms to 549 ± 35 ms in Pt1 and from 485 ± 32 ms to 452 ± 18 ms in Pt2. In both patients, the percentage of QTc values in the lower tertile increased strikingly: in V6 from 33% to 68% and from 33% to 76%; in DII from 33% to 50% and from 33% to 87%. In the wash-out period a rebound in QTc was observed. On treatment, both patients developed diarrhoea, Pt1 more than Pt2.

CONCLUSION

This represents the first attempt to validate in patients the in vitro results of a drug repurposing strategy for cardiovascular disorders. Lumacaftor + Ivacaftor shortened significantly the QTc in the two LQT2 patients with a trafficking defect, largely confirming the findings in their iPSC-CMs but with smaller quantitative changes. The findings are encouraging but immediate translation into clinical practice, without validation in more patients, would be premature.

Calcineurin Inhibitor-Based Immunosuppression and COVID-19: Results from a Multidisciplinary Cohort of Patients in Northern Italy

The role of immunosuppression in SARS-CoV-2-related disease (COVID-19) is a matter of debate. We here describe the course and the outcome of COVID-19 in a cohort of patients undergoing treatment with calcineurin inhibitors. In this monocentric cohort study, data were collected from the COVID-19 outbreak in Italy up to April 28th 2020. Patients were followed at our hospital for solid organ transplantation or systemic rheumatic disorders (RMDs) and were on calcineurin inhibitor (CNI)-based therapy. Selected patients were referred from the North of Italy. The aim of our study was to evaluate the clinical course of COVID-19 in this setting. We evaluated 385 consecutive patients (220 males, 57%; median age 61 years, IQR 48-69); 331 (86%) received solid organ transplantation and 54 (14%) had a RMD. CNIs were the only immunosuppressant administered in 47 patients (12%). We identified 14 (4%) COVID-19 patients, all transplanted, mainly presenting with fever (86%) and diarrhea (71%). Twelve patients were hospitalized and two of them died, both with severe comorbidities. No patients developed acute respiratory distress syndrome or infectious complications. The surviving 10 patients are now fully recovered. The clinical course of COVID-19 patients on CNIs is generally mild, and the risk of superinfection seems low.

Leptin affects the inflammatory response after STEMI

Leptin is an adipose tissue-derived hormone primarily involved in the regulation of food intake. Leptine has been shown to have a much broader role than just regulating body weight and appetite in response to food intake: among the others, it has been associated with increased ROS production and inflammation, factors involved in the restoration of an effective myocardial reperfusion after myocardial revascularization. Our study, to our best knowledge, is the first showing a direct relationship between leptin serum levels, inflammatory mediators of the ischemia reperfusion damage and effective myocardial reperfusion in patients with ST elevation myocardial infarction undergoing primary percutaneous coronary intervention. Our findings suggest that leptin serum levels are directly associated with the inflammatory response during an acute myocardial infarction and may have a role in risk stratification in this clinical setting.

P569Efficacy and safety of direct Xa oral inhibitors versus warfarin in patients with atrial fibrillation and cancer: a meta-analysis of randomized controlled trials

Background

Patients with cancer are at higher risk of atrial fibrillation (AF) compared with the general population. Furthermore, cancer per se and anti-cancer treatments have been associated with thromboembolic complications and increased bleeding risk. Considering that only 12% of cancer patients can achieve a stable International Normalized Ratio target and the frequent need for invasive procedures, warfarin is not an ideal option. Direct oral anticoagulants may theoretically represent a valid alternative although their use in this population has been scarcely investigated.

Purpose

To compare efficacy and safety of direct oral Xa inhibitors (DOXaI) versus warfarin in patients with atrial fibrillation and cancer.

Methods

We searched electronic databases for randomized controlled trials (RCTs) that analyzed the use of DOXaI versus warfarin in patients with AF and cancer. The primary efficacy outcome was stroke or systemic embolism (SE). The secondary efficacy outcomes were ischemic stroke, myocardial infarction and all-cause death. The primary safety outcome was major bleeding; secondary safety outcomes were major or clinically relevant non-major bleeding, intracranial bleeding and any bleeding. The net clinical benefit was estimated as the composite of the two primary outcomes. A sensitivity analysis was performed to better define the incidence of these outcomes in patients with active cancer. The statistical software ProMeta 3 was used to estimate the risk ratio with a random-effect model.

Results

3 RCTs counting a total of 3029 cancer patients (1682 on DOXaI and 1347 on warfarin), 1354  of whom with active cancer (856 on DOXaI and 502 on warfarin), were included in the analysis. Mean age was 75.6 ± 1.2 years, and 32% were female. Mean follow-up period was 2.2 ± 0.6 years. The most common cancer sites were prostate (23%), gastrointestinal tract (22.2%), breast (12.1%) and genitourinary tract (10.6%). The mean CHADS2 score was 2.9 ± 0.6 and the mean HAS-BLED score was 2.6 ± 0.4.

There were no significant differences in the risk of stroke or SE (RR 0.76; 95% CI 0.52-1.10) as well as for all the other secondary efficacy outcomes. DOXaI significantly reduced the incidence of major bleeding in the overall cancer population (RR 0.79; 95% CI 0.63-0.99; p = 0.039); this finding was consistent also in patients with active cancer (RR 0.79; 95% CI 0.59-1.05) although the effect was not statistically significant.  DOXaI also significantly reduced intracranial bleeding in overall cancer population (RR 0.12; 95% CI 0.02-0.63; p = 0.013) and any bleeding in active cancer patients (RR 0.87; 95% CI 0.77-0.98; p = 0.026). Furthermore, DOXaI significantly reduced the composite endpoints of major bleeding and stroke or SE in overall cancer population (RR 0.78; 95% CI 0.64-0.94; p = 0.008).

Conclusions

Our metanalysis shows that, in patients with atrial fibrillation and cancer, DOXaI are safer and have a similar efficacy compared with warfarin.

Abstract Figure. Primary efficacy and safety outcomes

P376Prognostic impact of atrial fibrillation in STEMI patients treated by primary percutaneous coronary intervention: a focus on cardiogenic shock

Background

Atrial fibrillation (AF) is a common finding in patients with ST elevation myocardial infarction (STEMI). However, its prognostic influence in MI remains controversial. Almost all previous studies were performed before the era of primary percutaneous coronary intervention (pPCI), and there is a lack of data in patients with  STEMI complicated by cardiogenic shock (CS). The aim of our study was to evaluate the prognostic impact of AF in a large real-world population of STEMI undergoing pPCI stratified by the presence of CS.

Methods

Our registry included 3017 consecutive patients with STEMI undergoing pPCI in our department in 2005-2017. The presence of a persistent (&gt;30 min) systolic blood pressure &lt; 90 mmHg associated with signs of pulmonary congestion/impaired end organ perfusion needing catecholamine infusion or mechanical support devices qualified for CS. Firstly we performed mortality analysis in all patients with AF during hospitalization; secondly, we compared patients with the first episode of AF and patients with AF during hospitalization but known AF in anamnesis.  The analysis was stratified for the presence of CS. Univariate (cross-tables and Kaplan-Meier curves with log-rank test) and multivariate mortality analysis (Cox regressions) were performed. In STEMI patients without CS we also performed a propensity-matched analysis including all variables known before STEMI that could influence the occurrence of a first episode of AF.

Results

AF was present in 337 (11.3%) patients during hospitalization; in 193 (57.3%) of them was the first episode. CS occurred in 250 patients (8.4%), 27.2% of whom were affected by an AF episode (86.5% as the first episode). Among patients without CS, AF occurred in 269 patients (9.7%) and for the 77.5% was the first episode. In CS patients, AF was not associated with increased mortality, neither at 30 days (43.5% vs 43.7%, p = 0.867) nor at 1 year (47.5% vs 53.1%, p = 0.633). In the population without CS, AF was an independent predictor of mortality both at 30 days (HR 2.25 (1.05; 4.82), p = 0.037) and at 1 year (HR 1.87 (1.094; 3.18), p = 0.022); only new-onset AF was an independent predictor of mortality.  We successfully matched 175 pairs of patients with similar propension to experience the first episode of AF. Among them the first episode of AF was confirmed to be an indipendent predictor of mortality (figure).

Conclusion

In the present large real-world cohort of unselected patients with STEMI, the presence of an episode of AF during hospitalization was an independent predictor of mortality in patients not complicated by cardiogenic shock. Conversely, AF did not show a significant prognostic impact in patients with STEMI complicated by CS.  Furthermore, the presence of a first episode of AF was confirmed to be an independent predictor of mortality, while an AF episode in patients with known AF was not found to have prognostic impact.

Abstract Figure

MTMR4 SNVs modulate ion channel degradation and clinical severity in congenital long QT syndrome: insights in the mechanism of action of protective modifier genes

Aims

In long QT syndrome (LQTS) patients, modifier genes modulate the arrhythmic risk associated with a disease-causing mutation. Their recognition can improve risk stratification and clinical management, but their discovery represents a challenge. We tested whether a cellular-driven approach could help to identify new modifier genes and especially their mechanism of action.

Methods and results

We generated human-induced pluripotent stem cell-derived cardiomyocytes (iPSC-CM) from two patients carrying the same KCNQ1-Y111C mutation, but presenting opposite clinical phenotypes. We showed that the phenotype of the iPSC-CMs derived from the symptomatic patient is due to impaired trafficking and increased degradation of the mutant KCNQ1 and wild-type human ether-a-go-go-related gene. In the iPSC-CMs of the asymptomatic (AS) patient, the activity of an E3 ubiquitin-protein ligase (Nedd4L) involved in channel protein degradation was reduced and resulted in a decreased arrhythmogenic substrate. Two single-nucleotide variants (SNVs) on the Myotubularin-related protein 4 (MTMR4) gene, an interactor of Nedd4L, were identified by whole-exome sequencing as potential contributors to decreased Nedd4L activity. Correction of these SNVs by CRISPR/Cas9 unmasked the LQTS phenotype in AS cells. Importantly, the same MTMR4 variants were present in 77% of AS Y111C mutation carriers of a separate cohort. Thus, genetically mediated interference with Nedd4L activation seems associated with protective effects.

Conclusion

Our finding represents the first demonstration of the cellular mechanism of action of a protective modifier gene in LQTS. It provides new clues for advanced risk stratification and paves the way for the design of new therapies targeting this specific molecular pathway.

NOS1AP polymorphisms reduce NOS1 activity and interact with prolonged repolarization in arrhythmogenesis

AIMS

NOS1AP single-nucleotide polymorphisms (SNPs) correlate with QT prolongation and cardiac sudden death in patients affected by long QT syndrome type 1 (LQT1). NOS1AP targets NOS1 to intracellular effectors. We hypothesize that NOS1AP SNPs cause NOS1 dysfunction and this may converge with prolonged action-potential duration (APD) to facilitate arrhythmias. Here we test (i) the effects of NOS1 inhibition and their interaction with prolonged APD in a guinea pig cardiomyocyte (GP-CMs) LQT1 model; (ii) whether pluripotent stem cell-derived cardiomyocytes (hiPSC-CMs) from LQT1 patients differing for NOS1AP variants and mutation penetrance display a phenotype compatible with NOS1 deficiency.

METHODS AND RESULTS

In GP-CMs, NOS1 was inhibited by S-Methyl-L-thiocitrulline acetate (SMTC) or Vinyl-L-NIO hydrochloride (L-VNIO); LQT1 was mimicked by IKs blockade (JNJ303) and β-adrenergic stimulation (isoproterenol). hiPSC-CMs were obtained from symptomatic (S) and asymptomatic (AS) KCNQ1-A341V carriers, harbouring the minor and major alleles of NOS1AP SNPs (rs16847548 and rs4657139), respectively. In GP-CMs, NOS1 inhibition prolonged APD, enhanced ICaL and INaL, slowed Ca2+ decay, and induced delayed afterdepolarizations. Under action-potential clamp, switching to shorter APD suppressed 'transient inward current' events induced by NOS1 inhibition and reduced cytosolic Ca2+. In S (vs. AS) hiPSC-CMs, APD was longer and ICaL larger; NOS1AP and NOS1 expression and co-localization were decreased.

CONCLUSION

The minor NOS1AP alleles are associated with NOS1 loss of function. The latter likely contributes to APD prolongation in LQT1 and converges with it to perturb Ca2+ handling. This establishes a mechanistic link between NOS1AP SNPs and aggravation of the arrhythmia phenotype in prolonged repolarization syndromes.