Cyclin E-induced replicative stress drives p53-dependent whole-genome duplication.

Whole-genome duplication (WGD) is a frequent event in cancer evolution and an important driver of aneuploidy. The role of the p53 tumor suppressor in WGD has been enigmatic: p53 can block the proliferation of tetraploid cells, acting as a barrier to WGD, but can also promote mitotic bypass, a key step in WGD via endoreduplication. In wild-type (WT) p53 tumors, WGD is frequently associated with activation of the E2F pathway, especially amplification of CCNE1, encoding cyclin E1. Here, we show that elevated cyclin E1 expression causes replicative stress, which activates ATR- and Chk1-dependent G2 phase arrest. p53, via its downstream target p21, together with Wee1, then inhibits mitotic cyclin-dependent kinase activity sufficiently to activate APC/CCdh1 and promote mitotic bypass. Cyclin E expression suppresses p53-dependent senescence after mitotic bypass, allowing cells to complete endoreduplication. Our results indicate that p53 can contribute to cancer evolution through the promotion of WGD.

The CMG Helicase Bypasses DNA-Protein Cross-Links to Facilitate Their Repair.

Covalent DNA-protein cross-links (DPCs) impede replication fork progression and threaten genome integrity. Using Xenopus egg extracts, we previously showed that replication fork collision with DPCs causes their proteolysis, followed by translesion DNA synthesis. We show here that when DPC proteolysis is blocked, the replicative DNA helicase CMG (CDC45, MCM2-7, GINS), which travels on the leading strand template, bypasses an intact leading strand DPC. Single-molecule imaging reveals that GINS does not dissociate from CMG during bypass and that CMG slows dramatically after bypass, likely due to uncoupling from the stalled leading strand. The DNA helicase RTEL1 facilitates bypass, apparently by generating single-stranded DNA beyond the DPC. The absence of RTEL1 impairs DPC proteolysis, suggesting that CMG must bypass the DPC to enable proteolysis. Our results suggest a mechanism that prevents inadvertent CMG destruction by DPC proteases, and they reveal CMG's remarkable capacity to overcome obstacles on its translocation strand.

Stromal-derived NRG1 enables oncogenic KRAS bypass in pancreas cancer.

Activating KRAS mutations (KRAS*) in pancreatic ductal adenocarcinoma (PDAC) drive anabolic metabolism and support tumor maintenance. KRAS* inhibitors show initial antitumor activity followed by recurrence due to cancer cell-intrinsic and immune-mediated paracrine mechanisms. Here, we explored the potential role of cancer-associated fibroblasts (CAFs) in enabling KRAS* bypass and identified CAF-derived NRG1 activation of cancer cell ERBB2 and ERBB3 receptor tyrosine kinases as a mechanism by which KRAS*-independent growth is supported. Genetic extinction or pharmacological inhibition of KRAS* resulted in up-regulation of ERBB2 and ERBB3 expression in human and murine models, which prompted cancer cell utilization of CAF-derived NRG1 as a survival factor. Genetic depletion or pharmacological inhibition of ERBB2/3 or NRG1 abolished KRAS* bypass and synergized with KRASG12D inhibitors in combination treatments in mouse and human PDAC models. Thus, we found that CAFs can contribute to KRAS* inhibitor therapy resistance via paracrine mechanisms, providing an actionable therapeutic strategy to improve the effectiveness of KRAS* inhibitors in PDAC patients.

Linkage reprogramming by tailor-made E3s reveals polyubiquitin chain requirements in DNA-damage bypass.

A polyubiquitin chain can adopt a variety of shapes, depending on how the ubiquitin monomers are joined. However, the relevance of linkage for the signaling functions of polyubiquitin chains is often poorly understood because of our inability to control or manipulate this parameter in vivo. Here, we present a strategy for reprogramming polyubiquitin chain linkage by means of tailor-made, linkage- and substrate-selective ubiquitin ligases. Using the polyubiquitylation of the budding yeast replication factor PCNA in response to DNA damage as a model case, we show that altering the features of a polyubiquitin chain in vivo can change the fate of the modified substrate. We also provide evidence for redundancy between distinct but structurally similar linkages, and we demonstrate by proof-of-principle experiments that the method can be generalized to targets beyond PCNA. Our study illustrates a promising approach toward the in vivo analysis of polyubiquitin signaling.

CHC22 clathrin recruitment to the early secretory pathway requires two-site interaction with SNX5 and p115.

The two clathrin isoforms, CHC17 and CHC22, mediate separate intracellular transport routes. CHC17 performs endocytosis and housekeeping membrane traffic in all cells. CHC22, expressed most highly in skeletal muscle, shuttles the glucose transporter GLUT4 from the ERGIC (endoplasmic-reticulum-to-Golgi intermediate compartment) directly to an intracellular GLUT4 storage compartment (GSC), from where GLUT4 can be mobilized to the plasma membrane by insulin. Here, molecular determinants distinguishing CHC22 from CHC17 trafficking are defined. We show that the C-terminal trimerization domain of CHC22 interacts with SNX5, which also binds the ERGIC tether p115. SNX5, and the functionally redundant SNX6, are required for CHC22 localization independently of their participation in the endosomal ESCPE-1 complex. In tandem, an isoform-specific patch in the CHC22 N-terminal domain separately mediates binding to p115. This dual mode of clathrin recruitment, involving interactions at both N- and C-termini of the heavy chain, is required for CHC22 targeting to ERGIC membranes to mediate the Golgi-bypass route for GLUT4 trafficking. Interference with either interaction inhibits GLUT4 targeting to the GSC, defining a bipartite mechanism regulating a key pathway in human glucose metabolism.

Processing of DNA Polymerase-Blocking Lesions during Genome Replication Is Spatially and Temporally Segregated from Replication Forks.

Tracing DNA repair factors by fluorescence microscopy provides valuable information about how DNA damage processing is orchestrated within cells. Most repair pathways involve single-stranded DNA (ssDNA), making replication protein A (RPA) a hallmark of DNA damage and replication stress. RPA foci emerging during S phase in response to tolerable loads of polymerase-blocking lesions are generally thought to indicate stalled replication intermediates. We now report that in budding yeast they predominantly form far away from sites of ongoing replication, and they do not overlap with any of the repair centers associated with collapsed replication forks or double-strand breaks. Instead, they represent sites of postreplicative DNA damage bypass involving translesion synthesis and homologous recombination. We propose that most RPA and recombination foci induced by polymerase-blocking lesions in the replication template are clusters of repair tracts arising from replication centers by polymerase re-priming and subsequent expansion of daughter-strand gaps over the course of S phase.

Early Injury Landscape in Vein Harvest by Single-Cell and Spatial Transcriptomics.

BACKGROUND: Vein graft failure following cardiovascular bypass surgery results in significant patient morbidity and cost to the healthcare system. Vein graft injury can occur during autogenous vein harvest and preparation, as well as after implantation into the arterial system, leading to the development of intimal hyperplasia, vein graft stenosis, and, ultimately, bypass graft failure. Although previous studies have identified maladaptive pathways that occur shortly after implantation, the specific signaling pathways that occur during vein graft preparation are not well defined and may result in a cumulative impact on vein graft failure. We, therefore, aimed to elucidate the response of the vein conduit wall during harvest and following implantation, probing the key maladaptive pathways driving graft failure with the overarching goal of identifying therapeutic targets for biologic intervention to minimize these natural responses to surgical vein graft injury. METHODS: Employing a novel approach to investigating vascular pathologies, we harnessed both single-nuclei RNA-sequencing and spatial transcriptomics analyses to profile the genomic effects of vein grafts after harvest and distension, then compared these findings to vein grafts obtained 24 hours after carotid-carotid vein bypass implantation in a canine model (n=4). RESULTS: Spatial transcriptomic analysis of canine cephalic vein after initial conduit harvest and distention revealed significant enrichment of pathways (P<0.05) involved in the activation of endothelial cells (ECs), fibroblasts, and vascular smooth muscle cells, namely pathways responsible for cellular proliferation and migration and platelet activation across the intimal and medial layers, cytokine signaling within the adventitial layer, and ECM (extracellular matrix) remodeling throughout the vein wall. Subsequent single-nuclei RNA-sequencing analysis supported these findings and further unveiled distinct EC and fibroblast subpopulations with significant upregulation (P<0.05) of markers related to endothelial injury response and cellular activation of ECs, fibroblasts, and vascular smooth muscle cells. Similarly, in vein grafts obtained 24 hours after arterial bypass, there was an increase in myeloid cell, protomyofibroblast, injury response EC, and mesenchymal-transitioning EC subpopulations with a concomitant decrease in homeostatic ECs and fibroblasts. Among these markers were genes previously implicated in vein graft injury, including VCAN, FBN1, and VEGFC, in addition to novel genes of interest, such as GLIS3 and EPHA3. These genes were further noted to be driving the expression of genes implicated in vascular remodeling and graft failure, such as IL-6, TGFBR1, SMAD4, and ADAMTS9. By integrating the spatial transcriptomics and single-nuclei RNA-sequencing data sets, we highlighted the spatial architecture of the vein graft following distension, wherein activated and mesenchymal-transitioning ECs, myeloid cells, and fibroblasts were notably enriched in the intima and media of distended veins. Finally, intercellular communication network analysis unveiled the critical roles of activated ECs, mesenchymal-transitioning ECs, protomyofibroblasts, and vascular smooth muscle cells in upregulating signaling pathways associated with cellular proliferation (MDK [midkine], PDGF [platelet-derived growth factor], VEGF [vascular endothelial growth factor]), transdifferentiation (Notch), migration (ephrin, semaphorin), ECM remodeling (collagen, laminin, fibronectin), and inflammation (thrombospondin), following distension. CONCLUSIONS: Vein conduit harvest and distension elicit a prompt genomic response facilitated by distinct cellular subpopulations heterogeneously distributed throughout the vein wall. This response was found to be further exacerbated following vein graft implantation, resulting in a cascade of maladaptive gene regulatory networks. Together, these results suggest that distension initiates the upregulation of pathological pathways that may ultimately contribute to bypass graft failure and presents potential early targets warranting investigation for targeted therapies. This work highlights the first applications of single-nuclei and spatial transcriptomic analyses to investigate venous pathologies, underscoring the utility of these methodologies and providing a foundation for future investigations.

Percutaneous Coronary Intervention Versus Coronary Artery Bypass Grafting in Patients With Left Main Disease With and Without Diabetes: Findings From a Pooled Analysis of 4 Randomized Clinical Trials.

BACKGROUND: Diabetes may be associated with differential outcomes in patients undergoing left main coronary revascularization with percutaneous coronary intervention (PCI) or coronary artery bypass grafting (CABG). The aim of this study was to investigate outcomes in patients with left main disease with and without diabetes randomized to PCI versus CABG. METHODS: Individual patient data were pooled from 4 trials (SYNTAX [Synergy Between PCI With Taxus and Cardiac Surgery], PRECOMBAT [Premier of Randomized Comparison of Bypass Surgery Versus Angioplasty Using Sirolimus-Eluting Stent in Patients With Left Main Coronary Artery Disease], NOBLE [Nordic-Baltic-British Left Main Revascularisation Study], and EXCEL [Evaluation of XIENCE Versus Coronary Artery Bypass Surgery for Effectiveness of Left Main Revascularization]) that randomized patients with left main disease to PCI or CABG. Patients were considered suitable for either approach. Patients were categorized by diabetes status. Kaplan-Meier event rates, Cox model hazard ratios, and interactions were assessed. RESULTS: Among 4393 patients, 1104 (25.1%) had diabetes. Patients with diabetes experienced higher rates of 5-year death (158/1104 [Kaplan-Meier rate, 14.7%] versus 297/3289 [9.3%]; P<0.001), spontaneous myocardial infarction (MI; 67/1104 [6.7%] versus 114/3289 [3.7%]; P<0.001), and repeat revascularization (189/1104 [18.5%] versus 410/3289 [13.2%]; P<0.001). Rates of all-cause mortality did not differ after PCI versus CABG in those with (84/563 [15.3%] versus 74/541 [14.1%]; hazard ratio, 1.11 [95% CI, 0.82-1.52]) or without (155/1634 [9.7%] versus 142/1655 [8.9%]; hazard ratio, 1.08 [95% CI, 0.86-1.36; PintHR=0.87) diabetes. Rates of stroke within 1 year were lower with PCI versus CABG in the entire population, with no heterogeneity based on diabetes status (PintHR=0.51). The 5-year rates of spontaneous MI and repeat coronary revascularization were higher after PCI regardless of diabetes status (spontaneous MI: 45/563 [8.9%] versus 22/541 [4.4%] in diabetes and 82/1634 [5.3%] versus 32/1655 [2.1%] in no diabetes, PintHR=0.47; repeat revascularization: 127/563 [24.5%] versus 62/541 [12.4%] in diabetes and 254/1634 [16.3%] versus 156/1655 [10.1%] in no diabetes, PintHR=0.18). For spontaneous MI and repeat revascularization, there were greater absolute risk differences beyond 1 year in patients with diabetes (4.9% and 9.9%) compared with those without (2.1% and 4.3%; PintARD=0.047 and 0.016). CONCLUSIONS: In patients with left main disease considered equally suitable for PCI or CABG and with largely low to intermediate SYNTAX scores, diabetes was associated with higher rates of death and cardiovascular events through 5 years. Compared with CABG, PCI resulted in no difference in the risk of death and a lower risk of early stroke regardless of diabetes status, and a higher risk of spontaneous MI and repeat coronary revascularization, with larger late absolute excess risks in patients with diabetes. REGISTRATION: URL: https://www.clinicaltrials.gov; Unique identifiers: NCT01205776, NCT0146651, NCT00422968, and NCT00114972.

2024 ACC/AHA/AACVPR/APMA/ABC/SCAI/SVM/SVN/SVS/SIR/VESS Guideline for the Management of Lower Extremity Peripheral Artery Disease: A Report of the American College of Cardiology/American Heart Association Joint Committee on Clinical Practice Guidelines.

AIM: The "2024 ACC/AHA/AACVPR/APMA/ABC/SCAI/SVM/SVN/SVS/SIR/VESS Guideline for the Management of Lower Extremity Peripheral Artery Disease" provides recommendations to guide clinicians in the treatment of patients with lower extremity peripheral artery disease across its multiple clinical presentation subsets (ie, asymptomatic, chronic symptomatic, chronic limb-threatening ischemia, and acute limb ischemia). METHODS: A comprehensive literature search was conducted from October 2020 to June 2022, encompassing studies, reviews, and other evidence conducted on human subjects that was published in English from PubMed, EMBASE, the Cochrane Library, CINHL Complete, and other selected databases relevant to this guideline. Additional relevant studies, published through May 2023 during the peer review process, were also considered by the writing committee and added to the evidence tables where appropriate. STRUCTURE: Recommendations from the "2016 AHA/ACC Guideline on the Management of Patients With Lower Extremity Peripheral Artery Disease" have been updated with new evidence to guide clinicians. In addition, new recommendations addressing comprehensive care for patients with peripheral artery disease have been developed.

Anticoagulation for post-operative atrial fibrillation after isolated coronary artery bypass grafting: a meta-analysis.

BACKGROUND AND AIMS: This study aimed to evaluate clinical outcomes in patients developing post-operative atrial fibrillation (POAF) after coronary artery bypass grafting (CABG) and characterize variations in oral anticoagulation (OAC) use, benefits, and complications. METHODS: A systematic search identified studies on new-onset POAF after CABG and OAC initiation. Outcomes included risks of thromboembolic events, bleeding, and mortality. Furthermore, a meta-analysis was conducted on these outcomes, stratified by the use or non-use of OAC. RESULTS: The identified studies were all non-randomized. Among 1 698 307 CABG patients, POAF incidence ranged from 7.9% to 37.6%. Of all POAF patients, 15.5% received OAC. Within 30 days, thromboembolic events occurred at rates of 1.0% (POAF: 0.3%; non-POAF: 0.8%) with 2.0% mortality (POAF: 1.0%; non-POAF: 0.5%). Bleeding rates were 1.1% for POAF patients and 2.7% for non-POAF patients. Over a median of 4.6 years, POAF patients had 1.73 thromboembolic events, 3.39 mortality, and 2.00 bleeding events per 100 person-years; non-POAF patients had 1.14, 2.19, and 1.60, respectively. No significant differences in thromboembolic risks [effect size -0.11 (-0.36 to 0.13)] and mortality [effect size -0.07 (-0.21 to 0.07)] were observed between OAC users and non-users. However, OAC use was associated with higher bleeding risk [effect size 0.32 (0.06-0.58)]. CONCLUSIONS: In multiple timeframes following CABG, the incidence of complications in patients who develop POAF is low. The use of OAC in patients with POAF after CABG is associated with increased bleeding risk.

Coronary flow capacity and survival prediction after revascularization: physiological basis and clinical implications.

BACKGROUND AND AIMS: Coronary flow capacity (CFC) is associated with an observed 10-year survival probability for individual patients before and after actual revascularization for comparison to virtual hypothetical ideal complete revascularization. METHODS: Stress myocardial perfusion (mL/min/g) and coronary flow reserve (CFR) per pixel were quantified in 6979 coronary artery disease (CAD) subjects using Rb-82 positron emission tomography (PET) for CFC maps of artery-specific size-severity abnormalities expressed as percent left ventricle with prospective follow-up to define survival probability per-decade as fraction of 1.0. RESULTS: Severely reduced CFC in 6979 subjects predicted low survival probability that improved by 42% after revascularization compared with no revascularization for comparable severity (P = .0015). For 283 pre-and-post-procedure PET pairs, severely reduced regional CFC-associated survival probability improved heterogeneously after revascularization (P < .001), more so after bypass surgery than percutaneous coronary interventions (P < .001) but normalized in only 5.7%; non-severe baseline CFC or survival probability did not improve compared with severe CFC (P = .00001). Observed CFC-associated survival probability after actual revascularization was lower than virtual ideal hypothetical complete post-revascularization survival probability due to residual CAD or failed revascularization (P < .001) unrelated to gender or microvascular dysfunction. Severely reduced CFC in 2552 post-revascularization subjects associated with low survival probability also improved after repeat revascularization compared with no repeat procedures (P = .025). CONCLUSIONS: Severely reduced CFC and associated observed survival probability improved after first and repeat revascularization compared with no revascularization for comparable CFC severity. Non-severe CFC showed no benefit. Discordance between observed actual and virtual hypothetical post-revascularization survival probability revealed residual CAD or failed revascularization.

Coronary bypass surgery guided by computed tomography in a low-risk population.

BACKGROUND AND AIMS: In patients with three-vessel disease and/or left main disease, selecting revascularization strategy based on coronary computed tomography angiography (CCTA) has a high level of virtual agreement with treatment decisions based on invasive coronary angiography (ICA). METHODS: In this study, coronary artery bypass grafting (CABG) procedures were planned based on CCTA without knowledge of ICA. The CABG strategy was recommended by a central core laboratory assessing the anatomy and functionality of the coronary circulation. The primary feasibility endpoint was the percentage of operations performed without access to the ICA. The primary safety endpoint was graft patency on 30-day follow-up CCTA. Secondary endpoints included topographical adequacy of grafting, major adverse cardiac and cerebrovascular (MACCE), and major bleeding events at 30 days. The study was considered positive if the lower boundary of confidence intervals (CI) for feasibility was ≥75% (NCT04142021). RESULTS: The study enrolled 114 patients with a mean (standard deviation) anatomical SYNTAX score and Society of Thoracic Surgery score of 43.6 (15.3) and 0.81 (0.63), respectively. Unblinding ICA was required in one case yielding a feasibility of 99.1% (95% CI 95.2%-100%). The concordance and agreement in revascularization planning between the ICA- and CCTA-Heart Teams was 82.9% with a moderate kappa of 0.58 (95% CI 0.50-0.66) and between the CCTA-Heart Team and actual treatment was 83.7% with a substantial kappa of 0.61 (95% CI 0.53-0.68). The 30-day follow-up CCTA in 102 patients (91.9%) showed an anastomosis patency rate of 92.6%, whilst MACCE was 7.2% and major bleeding 2.7%. CONCLUSIONS: CABG guided by CCTA is feasible and has an acceptable safety profile in a selected population of complex coronary artery disease.

Non-ST-elevation acute coronary syndromes with previous coronary artery bypass grafting: a meta-analysis of invasive vs. conservative management.

BACKGROUND AND AIMS: A routine invasive strategy is recommended in the management of higher risk patients with non-ST-elevation acute coronary syndromes (NSTE-ACSs). However, patients with previous coronary artery bypass graft (CABG) surgery were excluded from key trials that informed these guidelines. Thus, the benefit of a routine invasive strategy is less certain in this specific subgroup. METHODS: A systematic review and meta-analysis of randomized controlled trials (RCTs) was conducted. A comprehensive search was performed of PubMed, EMBASE, Cochrane, and ClinicalTrials.gov. Eligible studies were RCTs of routine invasive vs. a conservative or selective invasive strategy in patients presenting with NSTE-ACS that included patients with previous CABG. Summary data were collected from the authors of each trial if not previously published. Outcomes assessed were all-cause mortality, cardiac mortality, myocardial infarction, and cardiac-related hospitalization. Using a random-effects model, risk ratios (RRs) with 95% confidence intervals (CIs) were calculated. RESULTS: Summary data were obtained from 11 RCTs, including previously unpublished subgroup outcomes of nine trials, comprising 897 patients with previous CABG (477 routine invasive, 420 conservative/selective invasive) followed up for a weighted mean of 2.0 (range 0.5-10) years. A routine invasive strategy did not reduce all-cause mortality (RR 1.12, 95% CI 0.97-1.29), cardiac mortality (RR 1.05, 95% CI 0.70-1.58), myocardial infarction (RR 0.90, 95% CI 0.65-1.23), or cardiac-related hospitalization (RR 1.05, 95% CI 0.78-1.40). CONCLUSIONS: This is the first meta-analysis assessing the effect of a routine invasive strategy in patients with prior CABG who present with NSTE-ACS. The results confirm the under-representation of this patient group in RCTs of invasive management in NSTE-ACS and suggest that there is no benefit to a routine invasive strategy compared to a conservative approach with regard to major adverse cardiac events. These findings should be validated in an adequately powered RCT.

Coronary bypass surgery for multivessel disease after percutaneous coronary intervention in acute coronary syndromes: why, for whom, how early?

Multivessel coronary artery disease is present in ∼50% of patients with acute coronary syndrome and, compared with single-vessel disease, entails a higher risk of new ischaemic events and a worse prognosis. Randomized controlled trials have shown the superiority of 'complete revascularization' over culprit lesion-only treatment. Trials, however, only included patients treated with percutaneous coronary intervention (PCI), and evidence regarding complete revascularization with coronary artery bypass graft (CABG) surgery after culprit lesion-only PCI ('hybrid revascularization') is lacking. The CABG after PCI is an open, non-negligible therapeutic option, for patients with non-culprit left main and/or left anterior descending coronary artery disease where evidence in chronic coronary syndrome patients points in several cases to a preference of CABG over PCI. This valuable but poorly studied 'PCI first-CABG later' option presents, however, relevant challenges, mostly in the need of interrupting post-stenting dual antiplatelet therapy (DAPT) for surgery to prevent excess bleeding. Depending on patients' clinical characteristics and coronary anatomical features, either deferring surgery after a safe interruption of DAPT or bridging DAPT interruption with intravenous short-acting antithrombotic agents appears to be a suitable option. Off-pump minimally invasive surgical revascularization, associated with less operative bleeding than open-chest surgery, may be an adjunctive strategy when revascularization cannot be safely deferred and DAPT is not interrupted. Here, the rationale, patient selection, optimal timing, and adjunctive strategies are reviewed for an ideal approach to hybrid revascularization in post-acute coronary syndrome patients to support physicians' choices in a case-by-case patient-tailored approach.

Multiple arterial vs. single arterial coronary artery bypass grafting: sex-related differences in outcomes.

BACKGROUND AND AIMS: Uncertainty exists over whether multiple arterial grafting has a sex-related association with survival after coronary artery bypass grafting. This study aims to compare the long-term survival of using multiple arterial grafting vs. single arterial grafting in women and men undergoing coronary artery bypass grafting. METHODS: The retrospective study used the Australian and New Zealand Society of Cardiothoracic Surgical Database with linkage to the National Death Index. Patients from 2001 to 2020 were identified. Sex-stratified, inverse probability weighted Cox proportional hazard model was used to facilitate survival comparisons. The primary outcome was all-cause mortality. RESULTS: A total number of 54 275 adult patients receiving at least two grafts in primary isolated bypass operations were analysed. The entire study cohort consisted of 10 693 (19.7%) female patients and 29 711 (54.7%) multiple arterial grafting procedures. At a median (interquartile range) postoperative follow-up of 4.9 (2.3-8.4) years, mortality was significantly lower in male patients undergoing multiarterial than single arterial procedures (adjusted hazard ratio 0.82; 95% confidence interval 0.77-0.87; P < .001). The survival benefit was also significant for females (adjusted hazard ratio 0.83; 95% confidence interval 0.76-0.91; P < .001) at a median (interquartile range) follow-up of 5.2 (2.4-8.7) years. The interaction model from Cox regression suggested insignificant subgroup effect from sex (P = .08) on the observed survival advantage. The survival benefits associated with multiple arterial grafting were consistent across all sex-stratified subgroups except for female patients with left main coronary disease. CONCLUSIONS: Compared to single arterial grafting, multiple arterial revascularization is associated with improved long-term survival for women as well as men.

RNA sequencing unravels novel L cell constituents and mechanisms of GLP-1 secretion in human gastric bypass-operated intestine.

AIMS/HYPOTHESIS: Roux-en-Y gastric bypass surgery (RYGB) frequently results in remission of type 2 diabetes as well as exaggerated secretion of glucagon-like peptide-1 (GLP-1). Here, we assessed RYGB-induced transcriptomic alterations in the small intestine and investigated how they were related to the regulation of GLP-1 production and secretion in vitro and in vivo. METHODS: Human jejunal samples taken perisurgically and 1 year post RYGB (n=13) were analysed by RNA-seq. Guided by bioinformatics analysis we targeted four genes involved in cholesterol biosynthesis, which we confirmed to be expressed in human L cells, for potential involvement in GLP-1 regulation using siRNAs in GLUTag and STC-1 cells. Gene expression analyses, GLP-1 secretion measurements, intracellular calcium imaging and RNA-seq were performed in vitro. OGTTs were performed in C57BL/6j and iScd1-/- mice and immunohistochemistry and gene expression analyses were performed ex vivo. RESULTS: Gene Ontology (GO) analysis identified cholesterol biosynthesis as being most affected by RYGB. Silencing or chemical inhibition of stearoyl-CoA desaturase 1 (SCD1), a key enzyme in the synthesis of monounsaturated fatty acids, was found to reduce Gcg expression and secretion of GLP-1 by GLUTag and STC-1 cells. Scd1 knockdown also reduced intracellular Ca2+ signalling and membrane depolarisation. Furthermore, Scd1 mRNA expression was found to be regulated by NEFAs but not glucose. RNA-seq of SCD1 inhibitor-treated GLUTag cells identified altered expression of genes implicated in ATP generation and glycolysis. Finally, gene expression and immunohistochemical analysis of the jejunum of the intestine-specific Scd1 knockout mouse model, iScd1-/-, revealed a twofold higher L cell density and a twofold increase in Gcg mRNA expression. CONCLUSIONS/INTERPRETATION: RYGB caused robust alterations in the jejunal transcriptome, with genes involved in cholesterol biosynthesis being most affected. Our data highlight SCD as an RYGB-regulated L cell constituent that regulates the production and secretion of GLP-1.

Platelet transfusion enhances pro-aggregatory status shortly after coronary artery bypass grafting (CABG while modulating platelet pro-inflammatory state 1-week post-surgery.

During coronary artery bypass grafting (CABG), the surgical procedure, particularly the manipulation of the major arteries of the heart, induces a significant inflammatory state that may compromise platelet function to the extent that platelet transfusion is required. Given stored platelets as a major source of biological mediators, this study investigates the effects of platelet transfusion on the major pro-aggregatory, pro-inflammatory and immunomodulatory markers of platelets. Platelets from 20 patients, 10 who received platelet transfusion and 10 without, were subjected to flow cytometery where P-selectin and CD40 ligand (CD40L) expressions and PAC-1 binding (activation-specific anti GPIIb/GPIIIa antibody) analysed at five-time points of 24 h before surgery, immediately, 2 h, 24 h and 1 week after surgery. Analysis of intra-platelet transforming growth factor-beta-1 (TGF-ß1) was also conducted using western blotting. Patients with platelet transfusion showed increased levels of P-selectin, CD40L and intra-platelet TGF-ß1 2-h after surgery compared to those without transfusion (p < 0.05). PAC-1 binding was increased 24 h after surgery in transfused patients (p < 0.05). Given the significant post-transfusion elevation of platelet TGF-ß1, P-sel/CD40L reduction in transfused patients a week after was of much interest. This study showed for the first time the significant effects of platelet transfusion on the pro-inflammatory, pro-aggeregatory and immunomodulatory state of platelets in CABG patients, which manifested with immediate, midterm and delayed consequences. While the increased pro-inflammatory conditions manifested as an immediate effect of platelet transfusion, the pro-aggregatory circumstances emerged 24 h post-transfusion. A week after surgery, attenuations of pro-inflammatory markers of platelets in transfused patients were shown, which might be due to the immunomodulatory effects of TGF-ß1.

Computed Tomography Cardiac Angiography Before Invasive Coronary Angiography in Patients With Previous Bypass Surgery: The BYPASS-CTCA Trial.

BACKGROUND: Patients with previous coronary artery bypass grafting often require invasive coronary angiography (ICA). However, for these patients, the procedure is technically more challenging and has a higher risk of complications. Observational studies suggest that computed tomography cardiac angiography (CTCA) may facilitate ICA in this group, but this has not been tested in a randomized controlled trial. METHODS: This study was a single-center, open-label randomized controlled trial assessing the benefit of adjunctive CTCA in patients with previous coronary artery bypass grafting referred for ICA. Patients were randomized 1:1 to undergo CTCA before ICA or ICA alone. The co-primary end points were procedural duration of the ICA (defined as the interval between local anesthesia administration for obtaining vascular access and removal of the last catheter), patient satisfaction after ICA using a validated questionnaire, and the incidence of contrast-induced nephropathy. Linear regression was used for procedural duration and patient satisfaction score; contrast-induced nephropathy was analyzed using logistic regression. We applied the Bonferroni correction, with P<0.017 considered significant and 98.33% CIs presented. Secondary end points included incidence of procedural complications and 1-year major adverse cardiac events. RESULTS: Over 3 years, 688 patients were randomized with a median follow-up of 1.0 years. The mean age was 69.8±10.4 years, 108 (15.7%) were women, 402 (58.4%) were White, and there was a high burden of comorbidity (85.3% hypertension and 53.8% diabetes). The median time from coronary artery bypass grafting to angiography was 12.0 years, and there were a median of 3 (interquartile range, 2 to 3) grafts per participant. Procedure duration of the ICA was significantly shorter in the CTCA+ICA group (CTCA+ICA, 18.6±9.5 minutes versus ICA alone, 39.5±16.9 minutes [98.33% CI, -23.5 to -18.4]; P<0.001), alongside improved mean ICA satisfaction scores (1=very good to 5=very poor; -1.1 difference [98.33% CI, -1.2 to -0.9]; P<0.001), and reduced incidence of contrast-induced nephropathy (3.4% versus 27.9%; odds ratio, 0.09 [98.33% CI, 0.04-0.2]; P<0.001). Procedural complications (2.3% versus 10.8%; odds ratio, 0.2 [95% CI, 0.1-0.4]; P<0.001) and 1-year major adverse cardiac events (16.0% versus 29.4%; hazard ratio, 0.4 [95% CI, 0.3-0.6]; P<0.001) were also lower in the CTCA+ICA group. CONCLUSIONS: For patients with previous coronary artery bypass grafting, CTCA before ICA leads to reductions in procedure time and contrast-induced nephropathy, with improved patient satisfaction. CTCA before ICA should be considered in this group of patients. REGISTRATION: URL: https://www. CLINICALTRIALS: gov; Unique identifier: NCT03736018.

Fractional Flow Reserve-Guided PCI or Coronary Bypass Surgery for 3-Vessel Coronary Artery Disease: 3-Year Follow-Up of the FAME 3 Trial.

BACKGROUND: Previous studies comparing percutaneous coronary intervention (PCI) with coronary artery bypass grafting (CABG) in patients with multivessel coronary disease not involving the left main have shown significantly lower rates of death, myocardial infarction (MI), or stroke after CABG. These studies did not routinely use current-generation drug-eluting stents or fractional flow reserve (FFR) to guide PCI. METHODS: FAME 3 (Fractional Flow Reserve versus Angiography for Multivessel Evaluation) is an investigator-initiated, multicenter, international, randomized trial involving patients with 3-vessel coronary artery disease (not involving the left main coronary artery) in 48 centers worldwide. Patients were randomly assigned to receive FFR-guided PCI using zotarolimus drug-eluting stents or CABG. The prespecified key secondary end point of the trial reported here is the 3-year incidence of the composite of death, MI, or stroke. RESULTS: A total of 1500 patients were randomized to FFR-guided PCI or CABG. Follow-up was achieved in >96% of patients in both groups. There was no difference in the incidence of the composite of death, MI, or stroke after FFR-guided PCI compared with CABG (12.0% versus 9.2%; hazard ratio [HR], 1.3 [95% CI, 0.98-1.83]; P=0.07). The rates of death (4.1% versus 3.9%; HR, 1.0 [95% CI, 0.6-1.7]; P=0.88) and stroke (1.6% versus 2.0%; HR, 0.8 [95% CI, 0.4-1.7]; P=0.56) were not different. MI occurred more frequently after PCI (7.0% versus 4.2%; HR, 1.7 [95% CI, 1.1-2.7]; P=0.02). CONCLUSIONS: At 3-year follow-up, there was no difference in the incidence of the composite of death, MI, or stroke after FFR-guided PCI with current-generation drug-eluting stents compared with CABG. There was a higher incidence of MI after PCI compared with CABG, with no difference in death or stroke. These results provide contemporary data to allow improved shared decision-making between physicians and patients with 3-vessel coronary artery disease. REGISTRATION: URL: https://www. CLINICALTRIALS: gov; Unique identifier: NCT02100722.

Survival After Invasive or Conservative Management of Stable Coronary Disease.

BACKGROUND: The ISCHEMIA trial (International Study of Comparative Health Effectiveness With Medical and Invasive Approaches) compared an initial invasive versus an initial conservative management strategy for patients with chronic coronary disease and moderate or severe ischemia, with no major difference in most outcomes during a median of 3.2 years. Extended follow-up for mortality is ongoing. METHODS: ISCHEMIA participants were randomized to an initial invasive strategy added to guideline-directed medical therapy or a conservative strategy. Patients with moderate or severe ischemia, ejection fraction ≥35%, and no recent acute coronary syndromes were included. Those with an unacceptable level of angina were excluded. Extended follow-up for vital status is being conducted by sites or through central death index search. Data obtained through December 2021 are included in this interim report. We analyzed all-cause, cardiovascular, and noncardiovascular mortality by randomized strategy, using nonparametric cumulative incidence estimators, Cox regression models, and Bayesian methods. Undetermined deaths were classified as cardiovascular as prespecified in the trial protocol. RESULTS: Baseline characteristics for 5179 original ISCHEMIA trial participants included median age 65 years, 23% women, 16% Hispanic, 4% Black, 42% with diabetes, and median ejection fraction 0.60. A total of 557 deaths accrued during a median follow-up of 5.7 years, with 268 of these added in the extended follow-up phase. This included a total of 343 cardiovascular deaths, 192 noncardiovascular deaths, and 22 unclassified deaths. All-cause mortality was not different between randomized treatment groups (7-year rate, 12.7% in invasive strategy, 13.4% in conservative strategy; adjusted hazard ratio, 1.00 [95% CI, 0.85-1.18]). There was a lower 7-year rate cardiovascular mortality (6.4% versus 8.6%; adjusted hazard ratio, 0.78 [95% CI, 0.63-0.96]) with an initial invasive strategy but a higher 7-year rate of noncardiovascular mortality (5.6% versus 4.4%; adjusted hazard ratio, 1.44 [95% CI, 1.08-1.91]) compared with the conservative strategy. No heterogeneity of treatment effect was evident in prespecified subgroups, including multivessel coronary disease. CONCLUSIONS: There was no difference in all-cause mortality with an initial invasive strategy compared with an initial conservative strategy, but there was lower risk of cardiovascular mortality and higher risk of noncardiovascular mortality with an initial invasive strategy during a median follow-up of 5.7 years. REGISTRATION: URL: https://www. CLINICALTRIALS: gov; Unique identifier: NCT04894877.