Multimodal characterization of dilated cardiomyopathy: Geno- And Phenotyping of PrImary Cardiomyopathy (GrAPHIC).

AIMS: Cardiomyopathies (CMPs) are a heterogeneous group of diseases that are defined by structural and functional abnormalities of the cardiac muscle. Dilated cardiomyopathy (DCM), the most common CMP, is defined by left ventricular dilation and impaired contractility and represents a common cause of heart failure. Different phenotypes result from various underlying genetic and acquired causes with variable effects on disease development and progression, prognosis, and response to medical treatment. Current treatment algorithms do not consider these different aetiologies, due to lack of insights into treatable drivers of cardiac failure in patients with DCM. Our study aims to precisely phenotype and genotype the various subtypes of DCM and hereby lay the foundation for individualized therapy. METHODS AND RESULTS: The Geno- And Phenotyping of PrImary Cardiomyopathy (GrAPHIC) is a currently ongoing prospective observational monocentric cohort study that recruits patients with DCM after exclusion of other causes such as coronary artery disease, valvular dysfunction, myocarditis, exposure to toxins, and peripartum CMP. Patients are enrolled at our heart failure outpatient clinic or during hospitalization at the University Hospital Hamburg. Clinical parameters, multimodal imaging and functional assessment, cardiac biopsies, and blood samples are obtained to enable an integrated genomic, functional, and biomarker analysis. CONCLUSIONS: The GrAPHIC will contribute to a better understanding of the heterogeneous nature of primary CMPs focusing on DCM and provide improved prognostic approaches and more individualized therapies.

Genetic Contribution to End-Stage Cardiomyopathy Requiring Heart Transplantation.

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

Efficient in vivo genome editing prevents hypertrophic cardiomyopathy in mice.

Dominant missense pathogenic variants in cardiac myosin heavy chain cause hypertrophic cardiomyopathy (HCM), a currently incurable disorder that increases risk for stroke, heart failure and sudden cardiac death. In this study, we assessed two different genetic therapies-an adenine base editor (ABE8e) and a potent Cas9 nuclease delivered by AAV9-to prevent disease in mice carrying the heterozygous HCM pathogenic variant myosin R403Q. One dose of dual-AAV9 vectors, each carrying one half of RNA-guided ABE8e, corrected the pathogenic variant in ≥70% of ventricular cardiomyocytes and maintained durable, normal cardiac structure and function. An additional dose provided more editing in the atria but also increased bystander editing. AAV9 delivery of RNA-guided Cas9 nuclease effectively inactivated the pathogenic allele, albeit with dose-dependent toxicities, necessitating a narrow therapeutic window to maintain health. These preclinical studies demonstrate considerable potential for single-dose genetic therapies to correct or silence pathogenic variants and prevent the development of HCM.

Pathogenesis of Cardiomyopathy Caused by Variants in ALPK3, an Essential Pseudokinase in the Cardiomyocyte Nucleus and Sarcomere.

BACKGROUND: ALPK3 encodes α-kinase 3, a muscle-specific protein of unknown function. ALPK3 loss-of-function variants cause cardiomyopathy with distinctive clinical manifestations in both children and adults, but the molecular functions of ALPK3 remain poorly understood. METHODS: We explored the putative kinase activity of ALPK3 and the consequences of damaging variants using isogenic human induced pluripotent stem cell-derived cardiomyocytes, mice, and human patient tissues. RESULTS: Multiple sequence alignment of all human α-kinase domains and their orthologs revealed 4 conserved residues that were variant only in ALPK3, demonstrating evolutionary divergence of the ALPK3 α-kinase domain sequence. Phosphoproteomic evaluation of both ALPK3 kinase domain inhibition and overexpression failed to detect significant changes in catalytic activity, establishing ALPK3 as a pseudokinase. Investigations into alternative functions revealed that ALPK3 colocalized with myomesin proteins (MYOM1, MYOM2) at both the nuclear envelope and the sarcomere M-band. ALPK3 loss-of-function variants caused myomesin proteins to mislocalize and also dysregulated several additional M-band proteins involved in sarcomere protein turnover, which ultimately impaired cardiomyocyte structure and function. CONCLUSIONS: ALPK3 is an essential cardiac pseudokinase that inserts in the nuclear envelope and the sarcomere M-band. Loss of ALPK3 causes mislocalization of myomesins, critical force-buffering proteins in cardiomyocytes, and also dysregulates M-band proteins necessary for sarcomere protein turnover. We conclude that ALPK3 cardiomyopathy induces ventricular dilatation caused by insufficient myomesin-mediated force buffering and hypertrophy by impairment of sarcomere proteostasis.

Pathogenic variants damage cell composition and single cell transcription in cardiomyopathies.

Pathogenic variants in genes that cause dilated cardiomyopathy (DCM) and arrhythmogenic cardiomyopathy (ACM) convey high risks for the development of heart failure through unknown mechanisms. Using single-nucleus RNA sequencing, we characterized the transcriptome of 880,000 nuclei from 18 control and 61 failing, nonischemic human hearts with pathogenic variants in DCM and ACM genes or idiopathic disease. We performed genotype-stratified analyses of the ventricular cell lineages and transcriptional states. The resultant DCM and ACM ventricular cell atlas demonstrated distinct right and left ventricular responses, highlighting genotype-associated pathways, intercellular interactions, and differential gene expression at single-cell resolution. Together, these data illuminate both shared and distinct cellular and molecular architectures of human heart failure and suggest candidate therapeutic targets.

Ablation of lysophosphatidic acid receptor 1 attenuates hypertrophic cardiomyopathy in a mouse model.

Myocardial fibrosis is a key pathologic feature of hypertrophic cardiomyopathy (HCM). However, the fibrotic pathways activated by HCM-causing sarcomere protein gene mutations are poorly defined. Because lysophosphatidic acid is a mediator of fibrosis in multiple organs and diseases, we tested the role of the lysophosphatidic acid pathway in HCM. Lysphosphatidic acid receptor 1 (LPAR1), a cell surface receptor, is required for lysophosphatidic acid mediation of fibrosis. We bred HCM mice carrying a pathogenic myosin heavy-chain variant (403+/-) with Lpar1-ablated mice to create mice carrying both genetic changes (403+/- LPAR1 -/-) and assessed development of cardiac hypertrophy and fibrosis. Compared with 403+/- LPAR1WT, 403+/- LPAR1 -/- mice developed significantly less hypertrophy and fibrosis. Single-nucleus RNA sequencing of left ventricular tissue demonstrated that Lpar1 was predominantly expressed by lymphatic endothelial cells (LECs) and cardiac fibroblasts. Lpar1 ablation reduced the population of LECs, confirmed by immunofluorescence staining of the LEC markers Lyve1 and Ccl21a and, by in situ hybridization, for Reln and Ccl21a. Lpar1 ablation also altered the distribution of fibroblast cell states. FB1 and FB2 fibroblasts decreased while FB0 and FB3 fibroblasts increased. Our findings indicate that Lpar1 is expressed predominantly by LECs and fibroblasts in the heart and is required for development of hypertrophy and fibrosis in an HCM mouse model. LPAR1 antagonism, including agents in clinical trials for other fibrotic diseases, may be beneficial for HCM.

Plakophilin-2 truncating variants impair cardiac contractility by disrupting sarcomere stability and organization.

Progressive loss of cardiac systolic function in arrhythmogenic cardiomyopathy (ACM) has recently gained attention as an important clinical consideration in managing the disease. However, the mechanisms leading to reduction in cardiac contractility are poorly defined. Here, we use CRISPR gene editing to generate human induced pluripotent stem cells (iPSCs) that harbor plakophilin-2 truncating variants (PKP2tv), the most prevalent ACM-linked mutations. The PKP2tv iPSC­derived cardiomyocytes are shown to have aberrant action potentials and reduced systolic function in cardiac microtissues, recapitulating both the electrical and mechanical pathologies reported in ACM. By combining cell micropatterning with traction force microscopy and live imaging, we found that PKP2tvs impair cardiac tissue contractility by destabilizing cell-cell junctions and in turn disrupting sarcomere stability and organization. These findings highlight the interplay between cell-cell adhesions and sarcomeres required for stabilizing cardiomyocyte structure and function and suggest fundamental pathogenic mechanisms that may be shared among different types of cardiomyopathies.

Isolation of Nuclei from Mammalian Cells and Tissues for Single-Nucleus Molecular Profiling.

Both single-cell RNA sequencing (scRNAseq) and single-nucleus RNA sequencing (snRNAseq) can be used to characterize the transcriptional profile of individual cells, and based on these transcriptional profiles, help define cell type distribution in mixed cell populations. However, scRNAseq analyses are confounded if some of the cells are large (>50 µm) or if some of cells adhere more tightly to some adjacent cells than to others. Further, single cell isolation for scRNAseq requires fresh tissue, which may not be available for human or animal model tissues. Additionally, the current enzymatic and mechanical methods for single-cell dissociation can lead to stress-induced transcriptional artifacts. Nuclei for snRNAseq, on the other hand, can be isolated from any cell, regardless of size, and from either fresh or frozen tissues, and compared to whole cells, they are more resistant to mechanical pressures and appear not to exhibit as many cell isolation-based transcriptional artifacts. Here, we describe a time- and cost-effective procedure to isolate nuclei from mammalian cells and tissues. The protocol incorporates steps to mechanically disrupt samples to release nuclei. Compared to conventional nuclei isolation protocols, the approach described here increases overall efficiency, eliminates risk of contaminant exposure, and reduces volumes of expensive reagents. A series of RNA quality control checks are also incorporated to ensure success and reduce costs of subsequent snRNAseq experiments. Nuclei isolated by this procedure can be separated on the 10× Genomics Chromium system for either snRNAseq and/or Single-Nucleus ATAC-Seq (snATAC-Seq), and is also compatible with other single cell platforms. © 2021 Wiley Periodicals LLC. Basic Protocol 1: Sample preparation and quality control check via RNA Isolation and Analysis Basic Protocol 2: Nuclei Isolation.

Cells of the adult human heart.

Cardiovascular disease is the leading cause of death worldwide. Advanced insights into disease mechanisms and therapeutic strategies require a deeper understanding of the molecular processes involved in the healthy heart. Knowledge of the full repertoire of cardiac cells and their gene expression profiles is a fundamental first step in this endeavour. Here, using state-of-the-art analyses of large-scale single-cell and single-nucleus transcriptomes, we characterize six anatomical adult heart regions. Our results highlight the cellular heterogeneity of cardiomyocytes, pericytes and fibroblasts, and reveal distinct atrial and ventricular subsets of cells with diverse developmental origins and specialized properties. We define the complexity of the cardiac vasculature and its changes along the arterio-venous axis. In the immune compartment, we identify cardiac-resident macrophages with inflammatory and protective transcriptional signatures. Furthermore, analyses of cell-to-cell interactions highlight different networks of macrophages, fibroblasts and cardiomyocytes between atria and ventricles that are distinct from those of skeletal muscle. Our human cardiac cell atlas improves our understanding of the human heart and provides a valuable reference for future studies.

Hospital Volume and Outcome after Bilateral Internal Mammary Artery Grafting.

BACKGROUND: Bilateral internal mammary artery (BIMA) grafting largely is underutilized in patients undergoing coronary artery bypass grafting (CABG), partly because of the perceived increased complexity of the procedure. AIMS: In this study, we evaluated whether BIMA grafting can safely be performed also in centers, where this revascularization strategy infrequently is adopted. METHODS: Out of 6,783 patients from the prospective multicenter E-CABG study, who underwent isolated non- emergent CABG from January 2015 to December 2016, 2,457 underwent BIMA grafting and their outcome was evaluated in this analysis. RESULTS: The mean number of BIMA grafting per center was 82 cases/year and hospitals were defined as high or low volume, according to this cutoff value. Six hospitals were considered as centers with a high volume of BIMA grafting (no. of procedures ranging from 120 to 267/year; overall: 2,156; prevalence: 62.2%) and nine hospitals as centers with a low volume of BIMA grafting (no. of procedures ranging from 2 to 39/year; overall: 301; prevalence: 9.1%). Multilevel mixed-effects regression analysis showed that the low- and high-volume cohorts had similar outcomes. Propensity score one-to-one matching analysis of 292 pairs showed that the low-volume cohort had a significantly shorter intensive care unit stay (2.2 ± 2.3 versus 2.9 ± 4.8 days, P = .020). The rates of in-hospital death (1.0% versus 0.3%, P = .625), deep sternal wound infection/mediastinitis (3.8% versus 3.1%, P = .824), and 1-year survival (98.1% versus 99.7%, P = .180) as well as other outcomes were similar between the high- and low-volume cohorts. CONCLUSIONS: BIMA grafting can be safely performed also in centers in which this revascularization strategy is infrequently performed.

Venoarterial Extracorporeal Membrane Oxygenation After Surgical Repair of Type A Aortic Dissection.

Venoarterial (VA) extracorporeal membrane oxygenation (ECMO) support for postcardiotomy cardiogenic shock (PCS) in patients undergoing surgery for acute type A aortic dissection (TAAD) is controversial and the available evidence is confined to limited case series. We aimed to evaluate the impact of this salvage therapy in this patient population. Between January 2010 and March 2018, all TAAD patients receiving VA-ECMO for PCS were retrieved from the PC-ECMO registry. Hospital mortality and other secondary outcomes were compared with PCS patients undergoing surgery for other cardiac pathologies and treated with VA-ECMO. Among the 781 patients in the PC-ECMO registry, 62 (7.9%) underwent TAAD repair and required VA-ECMO support for PCS. In-hospital mortality accounted for 46 (74.2%) patients, while 23 (37.1%) were successfully weaned from VA-ECMO. No significant differences were observed between the TAAD and non-TAAD cohorts with reference to in-hospital mortality (74.2% vs 63.4%, p = 0.089). However, patients in the TAAD group had a higher rate of neurological events (33.9% vs 17.6%, p = 0.002), but similar rates of reoperation for bleeding/tamponade (48.4% vs 41.5%, p = 0.29), transfusion of ≥10 red blood cell units (77.4% vs 69.5%, p = 0.19), new-onset dialysis (56.7% vs 53.1%, p = 0.56), and other secondary outcomes. VA-ECMO provides a valid support for patients affected by PCS after surgery for TAAD.

The impact of residual mitral regurgitation after MitraClip therapy in functional mitral regurgitation.

AIMS: MitraClip therapy for the treatment of functional mitral regurgitation (FMR) is an increasingly used intervention for high-risk surgical patients. The aim of this observational study was to assess the impact of residual mitral regurgitation (rMR) at discharge on long-term outcome after MitraClip therapy in patients with FMR. METHODS AND RESULTS: Overall, 458 patients (mean age 73.8 ± 8.9 years) underwent MitraClip implantation between September 2008 and December 2017. The impact of rMR ≤ 1+ at discharge (n = 251) was retrospectively compared to patients graded as rMR 2+ (n = 173) and rMR ≥3+ (n = 34) at discharge. Median follow-up time was 5.09 years (5.00-5.26) with maximum follow-up of 10.02 years. The primary outcome was survival, and Kaplan-Meier analyses revealed significant differences among all rMR subgroups with highest survival rates for rMR ≤ 1+ patients. This was further confirmed by composite outcome analyses (P < 0.02). The inferior outcomes of rMR 2+ and rMR ≥ 3+ at discharge were confirmed by increased adjusted hazard ratios when rMR 2+ (1.54, P = 0.0039) and rMR ≥ 3+ (2.16, P = 0.011) were compared to rMR ≤ 1+. Moreover, patients with stable rMR ≤ 1+ grades within 12 months showed significantly higher survival rates compared to patients with rMR ≤ 1+ at discharge and rMR ≥ 2+ at 12-month follow-up or rMR ≥ 2+ at discharge and 12-month follow-up (P = 0.029). CONCLUSIONS: Patients with optimal and durable rMR ≤ 1+ at discharge and 12-month follow-up showed better outcome compared to patients with rMR 2+ and rMR ≥ 3+. Treatment success and durability characterized by rMR ≤ 1+ at discharge and 12 months seem to be important factors for long-term outcomes, which has to be further confirmed by prospective randomized trials.

SARS-CoV-2 entry factors are highly expressed in nasal epithelial cells together with innate immune genes.

We investigated SARS-CoV-2 potential tropism by surveying expression of viral entry-associated genes in single-cell RNA-sequencing data from multiple tissues from healthy human donors. We co-detected these transcripts in specific respiratory, corneal and intestinal epithelial cells, potentially explaining the high efficiency of SARS-CoV-2 transmission. These genes are co-expressed in nasal epithelial cells with genes involved in innate immunity, highlighting the cells' potential role in initial viral infection, spread and clearance. The study offers a useful resource for further lines of inquiry with valuable clinical samples from COVID-19 patients and we provide our data in a comprehensive, open and user-friendly fashion at www.covid19cellatlas.org.

Postcardiotomy Venoarterial Extracorporeal Membrane Oxygenation in Patients Aged 70 Years or Older.

BACKGROUND: There is uncertainty whether venoarterial extracorporeal membrane oxygenation (VA-ECMO) should be used in older patients with cardiopulmonary failure after cardiac surgery. METHODS: This was a retrospective multicenter study of 781 patients who required postcardiotomy VA-ECMO for cardiopulmonary failure after adult cardiac surgery from 2010 to 2018 at 19 cardiac surgery centers. A parallel systematic review with meta-analysis of the literature was performed. RESULTS: The hospital mortality in the overall Postcardiotomy Venoarterial Extracorporeal Membrane Oxygenation (PC-ECMO) series was 64.4%. A total of 255 patients were 70 years old or older (32.7%), and their hospital mortality was significantly higher than in younger patients (76.1% vs 58.7%; adjusted odds ratio, 2.199; 95% confidence interval [CI], 1.536 to 3.149). Arterial lactate level greater than 6 mmol/L before starting VA-ECMO was the only predictor of hospital mortality among patients 70 years old or older in univariate analysis (82.6% vs 70.4%; P = .029). Meta-analysis of current and previous studies showed that early mortality after postcardiotomy VA-ECMO was significantly higher in patients aged 70 years or older compared with younger patients (odds ratio, 2.09; 95% CI, 1.59 to 2.75; 5 studies including 1547 patients; I2, 5.9%). The pooled early mortality rate among patients aged 70 years or older was 78.8% (95% CI, 74.1 to 83.5; 6 studies including 617 patients; I2, 41.8%). Two studies reported 1-year mortality (including hospital mortality) of 79.9% and 75.6%, respectively, in patients 70 years old or older. CONCLUSIONS: Advanced age should not be considered a contraindication for postcardiotomy VA-ECMO. However, in view of the high risk of early mortality, meaningful scrutiny is needed before using VA-ECMO after cardiac surgery in older patients.

Bleeding in Patients Treated With Ticagrelor or Clopidogrel Before Coronary Artery Bypass Grafting.

BACKGROUND: We evaluated perioperative bleeding after coronary artery bypass grafting (CABG) in patients preoperatively treated with ticagrelor or clopidogrel, stratified by discontinuation of these P2Y12 inhibitors. METHODS: All patients from the prospective, European Multicenter Registry on Coronary Artery Bypass Grafting (E-CABG) treated with ticagrelor or clopidogrel undergoing isolated primary CABG were eligible. The primary outcome measure was severe or massive bleeding defined according to the Universal Definition of Perioperative Bleeding, stratified by P2Y12 inhibitor discontinuation. Secondary outcome measures included four additional definitions of major bleeding. Propensity score matching was performed to adjust for differences in preoperative and perioperative covariates. RESULTS: Of 2,311 patients who were included, 1,293 (55.9%) received clopidogrel and 1,018 (44.1%) ticagrelor preoperatively. Mean time between discontinuation and the operation was 4.5 ± 3.2 days for clopidogrel and 4.9 ± 3.0 days for ticagrelor. In the propensity score-matched cohort, ticagrelor-treated patients had a higher incidence of major bleeding according to Universal Definition of Perioperative Bleeding when ticagrelor was discontinued 0 to 2 days compared with 3 days before the operation (16.0% vs 2.7%, p = 0.003). Clopidogrel-treated patients had a higher incidence of major bleeding according to the Universal Definition of Perioperative Bleeding when clopidogrel was discontinued 0 to 3 days compared with 4 to 5 days before the operation (15.6% vs 8.3%, p = 0.031). CONCLUSIONS: In patients receiving ticagrelor 2 days before CABG and in those receiving clopidogrel 3 days before CABG, there was an increased rate of severe bleeding. Postponing nonemergent CABG for at least 3 days after discontinuation of ticagrelor and 4 days after clopidogrel should be considered.

Impact of preoperative thrombocytopenia on the outcome after coronary artery bypass grafting.

The impact of thrombocytopenia on postoperative bleeding and other major adverse events after cardiac surgery is unclear. This issue was investigated in a series of patients who underwent isolated coronary artery bypass grafting (CABG) from the prospective, multicenter E-CABG registry. Preoperative thrombocytopenia was defined as preoperative platelet count <150 × 109/L and it was considered moderate-severe when preoperative platelet count was <100 × 109/L. Multilevel mixed-effects regression analysis was performed to adjust the effect of thrombocytopenia on outcomes for baseline and operative covariates as well as for interinstitutional differences in patient-blood management. Among 7189 patients included in this analysis, 599 (8.3%) had preoperative thrombocytopenia. Patient with preoperative thrombocytopenia had an increased chest drainage output at 12 h (mean, 519 vs. 456 mL, adjusted coeff. 39, 95%CI 18-60) and rates of severe-massive bleeding (Universal Definition of Perioperative Bleeding (UDPB) severity grades 3-4: 12.7% vs. 8.1%, adjusted OR 1.47, 95%CI 1.11-1.93; E-CABG bleeding severity grades 2-3: 10.4% vs. 6.1%, adjusted OR 1.78, 95%CI 1.30-2.43). Thrombocytopenia was associated with an increased risk of hospital/30-day death (3.2% vs. 1.9%, adjusted OR 2.02, 95%CI 1.20-3.42), 1-year death (5.7% vs. 3.4%, adjusted HR 1.68, 95%CI 1.16-2.44), deep sternal wound infection (3.5% vs. 2.4%, adjusted OR 1.65, 95%CI 1.02-2.66), acute kidney injury (28.1% vs. 22.2%, OR 1.45, 1.18-1.78), and prolonged stay in the intensive care unit (mean, 3.6 vs 2.8 days, adjusted coeff. 0.74, 95%CI 0.40-1.09). Similar results were observed in a subset of patients with moderate-severe thrombocytopenia (51 patients, 0.7%). In particular, these patients had a markedly higher rate of acute kidney injury (40%, adjusted OR, 1.94, 95%CI 1.05-3.57), resternotomy for bleeding (7.8%, adjusted OR 3.49, 95%CI 1.20-10.21), and severe-massive bleeding (UDPB severity grades 3-4: 23.5%, adjusted OR 3.08, 95%CI 1.52-6.22; E-CABG bleeding severity grades 2-3: 23.5%, adjusted OR 4.43, 95%CI 2.15-9.15) compared to patients with normal preoperative platelet count. Mild preoperative thrombocytopenia is associated with increased risk of severe-massive bleeding, mortality, and other major adverse events after CABG. Such risks are markedly increased in patients with moderate-severe preoperative thrombocytopenia.

Prognostic Impact of Asymptomatic Carotid Artery Stenosis in Patients Undergoing Coronary Artery Bypass Grafting.

OBJECTIVES: The aim of this study was to evaluate the prognostic impact of untreated asymptomatic carotid artery stenosis (CS) in patients undergoing isolated coronary artery bypass grafting (CABG). METHODS: This was a post hoc analysis of data from a prospective multicentre observational study. Patients without history of stroke or transient ischaemic attack from the multicentre E-CABG registry who were screened for CS before isolated CABG were included. RESULTS: Among 2813 patients screened by duplex ultrasound and who did not undergo carotid intervention for asymptomatic CS, 11.1% had a stenosis of 50-59%, 6.0% of 60-69%, 3.1% of 70-79%, 1.4% of 80-89%, 0.5% of 90-99%, and 1.1% had carotid occlusion. In the screened population post-operative stroke occurred in 25 patients (0.9%), with an incidence of 1.5% among patients with CS ≥ 50% (n = 649). Pre-operative screening had not found a relevant CS in 15 of 25 patients suffering stroke after CABG. Brain imaging identified cerebral ischaemic injury in 20 patients, which was bilateral in five patients (25%), ipsilateral to a CS ≥ 50% in six (30%), and ipsilateral to a CS ≥ 70% in three (15%). In univariable analysis, the severity of CS was associated with a significantly increased risk of stroke (CS < 50%, 0.7%; 50-59%, 1.0%; 60-69%, 0.6%; 70-79%, 1.2%; 80-89%, 5.1%; 90-99%, 7.7%; occluded, 6.7%, p < .001). In multivariable analysis, a CS of 90-99% (OR 12.03, 95% CI 1.34-108.23) and the presence of an occluded internal carotid artery (OR 8.783, 95% CI 1.820-42.40) were independent predictors of stroke along with urgency of the procedure, severe massive bleeding according to the E-CABG classification, and the presence of a porcelain ascending aorta. CONCLUSIONS: Among screened patients with untreated asymptomatic patients, CS ≥ 90% was an independent predictor of post-operative stroke. As this condition has a low prevalence and when left untreated is associated with a relatively low rate of stroke, pre-operative screening of asymptomatic CS before CABG may not be justified. CLINICAL TRIAL REGISTRATION: https://clinicaltrials.gov. Unique identifier: NCT02319083.

Clinical frailty scale and outcome after coronary artery bypass grafting.

OBJECTIVES: The aim of this study was to assess the impact of frailty on the outcome after coronary artery bypass grafting (CABG) and whether it may improve the predictive ability of European System for Cardiac Operative Risk Evaluation (EuroSCORE II). METHODS: The Clinical Frailty Scale (CFS) was assessed preoperatively in patients undergoing isolated CABG from the multicentre E-CABG registry, and patients were stratified into 3 classes: scores 1-2, scores 3-4 and scores 5-7. RESULTS: Of the 6156 patients enrolled, 39.2% had CFS scores 1-2, 57.6% scores 3-4, and 3.2% scores 5-7. Logistic regression adjusted for multiple covariates showed that the CFS was an independent predictor of hospital/30-day mortality [CFS scores 3-4, odds ratio (OR) 3.95, 95% confidence interval (CI) 2.19-7.14; CFS scores 5-7, OR 5.90, 95% CI 2.67-13.05] and resulted in an Integrated Improvement Index of 1.3 (P < 0.001) and a Net Reclassification Index of 55.6 (P < 0.001) for prediction of hospital/30-day mortality. Adding the CFS classes to EuroSCORE II resulted in an Integrated Improvement Index of 0.9 (P < 0.001) and Net Reclassification Index of 59.6 (P < 0.001) for prediction of hospital/30-day mortality with a significantly larger area under the receiver operating characteristics curve (0.809 vs 0.781, P = 0.028). The CFS was an independent predictor of mid-term mortality [CFS scores 3-4, hazard ratio (HR) 2.05, 95% CI 1.43-2.85; CFS scores 5-7, HR 3.05, 95% CI 1.83-5.06]. CONCLUSIONS: The CFS predicted early- and mid-term mortality in patients undergoing isolated CABG. Further studies are needed to evaluate whether frailty may improve the estimation of the operative risk of patients undergoing adult cardiac surgery. Clinicaltrials.gov number: NCT02319083.

Variation in preoperative antithrombotic strategy, severe bleeding, and use of blood products in coronary artery bypass grafting: results from the multicentre E-CABG registry.

Aims: No data exists on inter-institutional differences in terms of adherence to international guidelines regarding the discontinuation of antithrombotics and rates of severe bleeding in coronary artery bypass grafting (CABG). Methods and results: This is an analysis of 7118 patients from the prospective multicentre European CABG (E-CABG) registry who underwent isolated CABG in 15 European centres. Preoperative pause of P2Y12 receptor antagonists shorter than that suggested by the 2017 ESC guidelines (overall 11.6%) ranged from 0.7% to 24.8% between centres (adjusted P < 0.0001) and increased the rate of severe-massive bleeding [E-CABG bleeding grades 2-3, OR 1.66, 95% confidence interval (CI) 1.27-2.17; Universal Definition of Perioperative Bleeding (UDPB) bleeding grades 3-4, OR 1.50, 95% CI 1.16-1.93]. The incidence of resternotomy for bleeding (overall 2.6%) ranged from 0% to 6.9% (adjusted P < 0.0001), and surgical site bleeding (overall 59.6%) ranged from 0% to 84.6% (adjusted P = 0.003). The rate of the UDPB bleeding grades 3-4 (overall 8.4%) ranged from 3.7% to 22.3% (P < 0.0001), and of the E-CABG bleeding grades 2-3 (overall 6.5%) ranged from 0.4% to 16.4% between centres (P < 0.0001). Resternotomy for bleeding (adjusted OR 5.04, 95% CI 2.85-8.92), UDPB bleeding grades 3-4 (adjusted OR 6.61, 95% CI 4.42-9.88), and E-CABG bleeding grades 2-3 (adjusted OR 8.71, 95% CI 5.76-13.15) were associated with an increased risk of hospital/30-day mortality. Conclusions: Adherence to the current guidelines on the early discontinuation of P2Y12 receptor antagonists is of utmost importance to reduce excessive bleeding and early mortality after CABG. Inter-institutional variation should be considered for a correct interpretation of the results in multicentre studies evaluating perioperative bleeding and use of blood products.

Utility of glycated hemoglobin screening in patients undergoing elective coronary artery surgery: Prospective, cohort study from the E-CABG registry.

BACKGROUND: Patients with increased glycated hemoglobin (HbA1c) seem to be at increased risk of sternal wound infection (SWI) after coronary artery bypass grafting (CABG). However, it is unclear whether increased baseline HbA1c levels may affect other postoperative outcomes. MATERIAL AND METHODS: Data on preoperative levels of HbA1c were collected from 2606 patients undergoing elective isolated CABG from 2015 to 2016 and included in the prospective, multicenter E-CABG registry. RESULTS: The prevalence of HbA1c ≥ 53 mmol/mol (7.0%) among non-diabetics was 5.3%, among non-insulin dependent diabetics was 53.5% and among insulin dependent diabetics was 67.1% (p < 0.001). The prevalence of HbA1c > 75 mmol/mol (9.0%) among non-diabetics was 0.5%, among non-insulin dependent diabetics was 5.8% and among insulin dependent diabetics was 10.6% (p < 0.001). Baseline levels of HbA1c ≥ 53 mmol/mol (7.0%) was a significant predictor of any SWI (10.7% vs. 3.3%, adjusted p-value: <0.001), deep SWI/mediastinitis (3.8% vs. 1.3%, adjusted p-value: 0.001) and acute kidney injury (27.4% vs. 19.8%, adjusted p-value: 0.042). These findings were confirmed in multilevel mixed effect logistic regression adjusted for participating centers. Among patients with diabetes, HbA1c ≥ 53 mmol/mol (7.0%) was predictive of SWI (11.1% vs. 4.8%, p = 0.001). CONCLUSIONS: HbA1c is increased in a significant proportion of patients undergoing elective CABG and these patients are at higher risk of SWI. Less clear is the impact of increased HbA1c on other postoperative outcomes. These results do not support screening of HbA1c in patients without history of diabetes. Preoperative screening of HbA1c is valuable only to identify diabetics at risk of SWI.