Saphenous Vein Graft Failure: From Pathophysiology to Prevention and Treatment Strategies

Rationale and design of a single-center randomized trial to compare the graft patency between the radial artery and the no-touch saphenous vein in coronary artery bypass grafting surgery (GRAFT-CAB Study)

BACKGROUND

Previous studies suggested only the radial artery and the No-touch (NT) technique were effective in reducing graft occlusion after coronary artery bypass grafting (CABG) surgery. However, there is no randomized trial comparing these 2 graft conduits. The optimum second conduit for CABG remains undetermined.

MATERIALS AND METHODS

This study is a prospective, single-center randomized clinical trial, aiming to compare the graft patency between the radial artery and the NT vein graft. All patients undergoing isolated CABG with left internal mammary artery (LIMA) plus at least 2 additional grafts will be considered eligible. About 774 cases (516 in the radial artery group and 258 in the NT vein group) will be enrolled in over 1 to 2 years. Participants will be randomized and allocated to two bypass strategies: the LIMA plus 1 radial artery and 1 conventional vein graft, or the LIMA plus 2 NT vein grafts. The primary outcome is graft occlusion at 1 year after CABG evaluated by CT angiography. The secondary outcomes include graft occlusion at 3 and 5 years and major adverse cardiac or cerebrovascular events at 1, 3, and 5 years follow-ups.

DISCUSSION

This study will define whether or not the NT vein has a lower graft occlusion rate than the radial artery in short and mid-term follow-ups, and provide new evidence for the second conduit choice in CABG surgery.

TRIAL REGISTRATION

ClinicalTrials.gov NCT06014047. Registered on October 15th, 2023.

Antiplatelet therapy after coronary artery bypass surgery: five year follow-up of randomised DACAB trial

OBJECTIVE

To assess the effect of different antiplatelet strategies on clinical outcomes after coronary artery bypass grafting.

DESIGN

Five year follow-up of randomised Different Antiplatelet Therapy Strategy After Coronary Artery Bypass Grafting (DACAB) trial.

SETTING

Six tertiary hospitals in China; enrolment between July 2014 and November 2015; completion of five year follow-up from August 2019 to June 2021.

PARTICIPANTS

500 patients aged 18-80 years (including 91 (18.2%) women) who had elective coronary artery bypass grafting surgery and completed the DACAB trial.

INTERVENTIONS

Patients were randomised 1:1:1 to ticagrelor 90 mg twice daily plus aspirin 100 mg once daily (dual antiplatelet therapy; n=168), ticagrelor monotherapy 90 mg twice daily (n=166), or aspirin monotherapy 100 mg once daily (n=166) for one year after surgery. After the first year, antiplatelet therapy was prescribed according to standard of care by treating physicians.

MAIN OUTCOME MEASURES

The primary outcome was major adverse cardiovascular events (a composite of all cause death, myocardial infarction, stroke, and coronary revascularisation), analysed using the intention-to-treat principle. Time-to-event analysis was used to compare the risk between treatment groups. Multiple post hoc sensitivity analyses examined the robustness of the findings.

RESULTS

Follow-up at five years for major adverse cardiovascular events was completed for 477 (95.4%) of 500 patients; 148 patients had major adverse cardiovascular events, including 39 in the dual antiplatelet therapy group, 54 in the ticagrelor monotherapy group, and 55 in the aspirin monotherapy group. Risk of major adverse cardiovascular events at five years was significantly lower with dual antiplatelet therapy versus aspirin monotherapy (22.6% v 29.9%; hazard ratio 0.65, 95% confidence interval 0.43 to 0.99; P=0.04) and versus ticagrelor monotherapy (22.6% v 32.9%; 0.66, 0.44 to 1.00; P=0.05). Results were consistent in all sensitivity analyses.

CONCLUSIONS

Treatment with ticagrelor dual antiplatelet therapy for one year after surgery reduced the risk of major adverse cardiovascular events at five years after coronary artery bypass grafting compared with aspirin monotherapy or ticagrelor monotherapy.

TRIAL REGISTRATION

NCT03987373ClinicalTrials.gov NCT03987373.

Association between overweight and obesity with coronary artery bypass graft failure: an individual patient data analysis of clinical trials

OBJECTIVES

The association between obesity and graft failure after coronary artery bypass grafting has not been previously investigated.

METHODS

We pooled individual patient data from randomized clinical trials with systematic postoperative coronary imaging to evaluate the association between obesity and graft failure at the individual graft and patient levels. Penalized cubic regression splines and mixed-effects multivariable logistic regression models were performed.

RESULTS

Six trials comprising 3928 patients and 12 048 grafts were included. The median time to imaging was 1.03 (interquartile range 1.00-1.09) years. By body mass index (BMI) category, 800 (20.4%) patients were normal weight (BMI 18.5-24.9), 1668 (42.5%) were overweight (BMI 25-29.9), 983 (25.0%) were obesity class 1 (BMI 30-34.9), 344 (8.8%) were obesity class 2 (BMI 35-39.9) and 116 (2.9%) were obesity class 3 (BMI 40+). As a continuous variable, BMI was associated with reduced graft failure [adjusted odds ratio (aOR) 0.98 (95% confidence interval (CI) 0.97-0.99)] at the individual graft level. Compared to normal weight patients, graft failure at the individual graft level was reduced in overweight [aOR 0.79 (95% CI 0.64-0.96)], obesity class 1 [aOR 0.81 (95% CI 0.64-1.01)] and obesity class 2 [aOR 0.61 (95% CI 0.45-0.83)] patients, but not different compared to obesity class 3 [aOR 0.94 (95% CI 0.62-1.42)] patients. Findings were similar, but did not reach significance, at the patient level.

CONCLUSIONS

In a pooled individual patient data analysis of randomized clinical trials, BMI and obesity appear to be associated with reduced graft failure at 1 year after coronary artery bypass grafting.

Optimal Conduit Diameter Selection in Coronary Bypass Grafting Using Saphenous Vein

BACKGROUND

Predictors of long-term saphenous vein graft (SVG) patency following coronary artery bypass grafting (CABG) include harvesting technique, degree of proximal coronary stenosis, and target vessel diameter and runoff. The objective of this study was to evaluate the association between vein graft diameter and long-term survival.

METHODS

Patients undergoing primary CABG (2000-2017) at Flinders Medical Centre, Adelaide, Australia, were categorised into three groups according to average SVG diameter (<3.5 mm [small], 3.5-4 mm [medium], >4 mm [large]). Survival data was obtained from the Australian Institute of Health and Welfare National Death Index. To determine the association of SVG diameter with long-term survival we used Kaplan-Meier survival analysis and Cox proportional hazard models adjusted for preoperative variables associated with survival.

RESULTS

Vein graft diameter was collected in 3,797 patients. Median follow-up time was 7.6 years (interquartile range, 3.9-11.8) with 1,377 deaths. SVG size >4 mm was associated with lower rates of adjusted survival up to 4 years postoperatively (hazard ratio 1.48; 95% confidence interval 1.05-2.1; p=0.026).

CONCLUSIONS

Vein graft diameter >4mm was found to be associated with lower rates of survival following CABG.

Hemodynamics and Wall Mechanics of Vascular Graft Failure

Blood vessels are subjected to complex biomechanical loads, primarily from pressure-driven blood flow. Abnormal loading associated with vascular grafts, arising from altered hemodynamics or wall mechanics, can cause acute and progressive vascular failure and end-organ dysfunction. Perturbations to mechanobiological stimuli experienced by vascular cells contribute to remodeling of the vascular wall via activation of mechanosensitive signaling pathways and subsequent changes in gene expression and associated turnover of cells and extracellular matrix. In this review, we outline experimental and computational tools used to quantify metrics of biomechanical loading in vascular grafts and highlight those that show potential in predicting graft failure for diverse disease contexts. We include metrics derived from both fluid and solid mechanics that drive feedback loops between mechanobiological processes and changes in the biomechanical state that govern the natural history of vascular grafts. As illustrative examples, we consider application-specific coronary artery bypass grafts, peripheral vascular grafts, and tissue-engineered vascular grafts for congenital heart surgery as each of these involves unique circulatory environments, loading magnitudes, and graft materials.

One-month DAPT with ticagrelor and aspirin for patients undergoing coronary artery bypass grafting: rationale and design of the randomised, multicentre, double-blind, placebo-controlled ODIN trial

The optimal antiplatelet strategy after coronary artery bypass graft (CABG) surgery in patients with chronic coronary syndromes (CCS) is unclear. Adding the P2Y12 inhibitor, ticagrelor, to low-dose aspirin for 1 year is associated with a reduction in graft failure, particularly saphenous vein grafts, at the expense of an increased risk of clinically important bleeding. As the risk of thrombotic graft failure and ischaemic events is highest early after CABG surgery, a better risk-to-benefit profile may be attained with short-term dual antiplatelet therapy followed by single antiplatelet therapy. The One Month Dual Antiplatelet Therapy With Ticagrelor in Coronary Artery Bypass Graft Patients (ODIN) trial is a prospective, randomised, double-blind, placebo-controlled, international, multicentre study of 700 subjects that will evaluate the effect of short-term dual antiplatelet therapy with ticagrelor plus low-dose aspirin after CABG in patients with CCS. Patients will be randomised 1:1 to ticagrelor 90 mg twice daily or matching placebo, in addition to aspirin 75-150 mg once daily for 1 month; after the first month, antiplatelet therapy will be continued with aspirin alone. The primary endpoint is a hierarchical composite of all-cause death, stroke, myocardial infarction, revascularisation and graft failure at 1 year. The key secondary endpoint is a hierarchical composite of all-cause death, stroke, myocardial infarction, Bleeding Academic Research Consortium (BARC) type 3 bleeding, revascularisation and graft failure at 1 year (net clinical benefit). ODIN will report whether the addition of ticagrelor to low-dose aspirin for 1 month after CABG reduces ischaemic events and provides a net clinical benefit in patients with CCS. (ClinicalTrials.gov: NCT05997693).

Primary percutaneous intervention in an unusual vessel using an unusual technique: a case report

Background

Primary percutaneous intervention (PPCI) of the saphenous vein graft (SVG) is associated with a high risk of distal embolization and no reflow, since SVG lesions are often very friable and have a large thrombotic burden. We report a case of successful PPCI of the SVG using guide catheter thrombectomy with novel double wire technique.

Case summary

A 60-year-old male with a past history of coronary artery bypass grafting presented with acute thrombotic occlusion of the SVG to the obtuse marginal graft. Despite appropriate pharmacotherapy (GPIIb/IIIa inhibitors) and thrombosuction, there was a large residual thrombus burden with poor distal flow. In the present case, we decided to perform guide catheter thrombosuction. An exchange length floppy 0.014' wire was passed alongside the pre-existing wire and the 6 Fr JR guide catheter was exchanged for a less traumatic 5 Fr JR guide catheter over the exchange wire. The first wire was kept distally in the vessel along the guiding catheter to maintain the access to the graft vessel. The 5 Fr JR guide catheter was slowly advanced over the wire to the distal portion of the graft, keeping the other wire in the distal portion of the graft to maintain access. A large amount of thrombus was aspirated and the patient improved dramatically.

Discussion

This double wire technique is an effortless and novel way to maintain access to the distal vasculature of the occluded artery, while the guide can be safely intubated deep into the coronary artery that helps in removing a very large amount of thrombus because of their larger internal lumen.

Impact of Graft Velocity on Saphenous Vein Graft Atherosclerosis after Coronary Artery Bypass Grafting

PURPOSE

Saphenous vein grafts (SVGs) sometimes occur as vein graft stenosis or failure in coronary artery bypass grafting. The purpose of this study was to detect the factors affecting vein graft atherosclerosis.

METHODS

We performed two analysis. In the first analysis, we enrolled 120 grafts using conventionally harvested saphenous vein graft (C-SVG) and followed-up with multiple coronary computed tomography angiography (CCTA). We examined the factors that contribute to the graft atherosclerosis defined by graft failure at subsequent CCTA or substantial progression of graft stenosis (a decrease of ≥0.6 mm in diameter). In the second analysis, 66 grafts using no-touch harvested saphenous vein graft (N-SVG) were compared with those in the first analysis using C-SVG, focusing on the differences in intraoperative factors using propensity score-matched analysis.

RESULTS

In the first analysis, graft atherosclerosis+ group comprised 27 grafts, which had a larger SVG diameter, lower graft velocity, and higher graft/native ratio in diameter than the graft atherosclerosis- group. In the multivariable analysis, slow graft velocity and graft/native ≥2 in diameter were independently associated with the graft atherosclerosis. In the second analysis, the N-SVG group had a much greater graft velocity than the C-SVG group.

CONCLUSION

Lower graft velocity and higher graft/native ratio in diameter were associated with the graft atherosclerosis. The N-SVG group had increased graft velocity, which may contribute to prevent the graft atherosclerosis.(Trial registration: UMIN Clinical Trial Registry no. UMIN000050482. Registered 3 March 2023, retrospectively registered.).

Lymphedema after saphenous harvesting for coronary artery bypass surgery: case report and literature review

Different causes have been described for secondary lymphedema as reported in this article. A 75-year-old man was diagnosed with lymphedema about one decade after saphenous harvesting for coronary artery bypass surgery. It took two years for him to find out his diagnosis and receive the proper treatment. After standard complete decongestive therapy, his volume and pain decreased and his quality of life was improved, especially its physical aspect. It is important to recognize the possibility of lymphedema development after saphenous harvesting among patients undergoing coronary artery bypass surgery to prevent significant disturbance of quality of life with timely management.

Coronary Artery Bypass Surgery: Evidence-Based Practice

Coronary artery bypass graft (CABG) surgery remains a pivotal cornerstone, offering established symptomatic alleviation and prognostic advantages for patients grappling with complex multivessel and left main coronary artery diseases. Despite the lucid guidance laid out by contemporary guidelines regarding the choice between CABG and percutaneous coronary intervention (PCI), a notable hesitation persists among certain patients, characterized by psychological reservations, knowledge gaps, or individual beliefs that sway their inclination toward surgical intervention. This comprehensive review critically synthesizes the prevailing guidelines, modern practices, and outcomes pertaining to CABG surgery, delving into an array of techniques and advancements poised to enhance both short-term and enduring surgical outcomes. The exploration encompasses advances in on-pump and off-pump procedures, conduit selection strategies encompassing the bilateral utilization of internal mammary artery and radial artery conduits, meticulous graft evaluation methodologies, and the panorama of minimally invasive approaches, including those assisted by robotic technology. Furthermore, the review navigates the terrain of hybrid coronary revascularization, shedding light on the pivotal roles of shared decision-making and the heart team in shaping treatment pathways. As a comprehensive compendium, this review not only navigates the intricate landscape of CABG surgery but also aligns it with contemporary practices, envisioning its trajectory within the evolving currents of healthcare dynamics.

Tongmai Yangxin pill alleviates myocardial no-reflow by activating GPER to regulate HIF-1α signaling and downstream potassium channels

CONTEXT

The Tongmai Yangxin pill (TMYX) has potential clinical effects on no-reflow (NR); however, the effective substances and mechanisms remain unclear.

OBJECTIVE

This study evaluates the cardioprotective effects and molecular mechanisms of TMYX against NR.

MATERIALS AND METHODS

We used a myocardial NR rat model to confirm the effect and mechanism of action of TMYX in alleviating NR. Sprague-Dawley (SD) rats were divided into Control (Con), sham, NR, TMYX (4.0 g/kg), and sodium nitroprusside (SNP, 5.0 mg/kg), and received their treatments once a day for one week. In vitro studies in isolated coronary microvasculature of NR rats and in silico network pharmacology analyses were performed to reveal the underlying mechanisms of TMYX and determine the main components, targets, and pathways of TMYX, respectively.

RESULTS

TMYX (4.0 g/kg) showed therapeutic effects on NR by improving the cardiac structure and function, reducing NR, ischemic areas, and cardiomyocyte injury, and decreasing the expression of cardiac troponin I (cTnI). Moreover, the mechanism of TMYX predicted by network pharmacology is related to the HIF-1, NF-κB, and TNF signaling pathways. In vivo, TMYX decreased the expression of MPO, NF-κB, and TNF-α and increased the expression of GPER, p-ERK, and HIF-1α. In vitro, TMYX enhanced the diastolic function of coronary microvascular cells; however, this effect was inhibited by G-15, H-89, L-NAME, ODQ and four K⁺ channel inhibitors.

CONCLUSIONS

TMYX exerts its pharmacological effects in the treatment of NR via multiple targets. However, the contribution of each pathway was not detected, and the mechanisms should be further investigated.

Integrative multiomics analysis of neointima proliferation in human saphenous vein: implications for bypass graft disease

Introduction

Human saphenous veins (SV) are widely used as grafts in coronary artery bypass (CABG) surgery but often fail due to neointima proliferation (NP). NP involves complex interplay between vascular smooth muscle cells (VSMC) and fibroblasts. Little is known, however, regarding the transcriptomic and proteomic dynamics of NP. Here, we performed multi-omics analysis in an ex vivo tissue culture model of NP in human SV procured for CABG surgery.

Methods and results

Histological examination demonstrated significant elastin degradation and NP (indicated by increased neointima area and neointima/media ratio) in SV subjected to tissue culture. Analysis of data from 73 patients suggest that the process of SV adaptation and NP may differ according to sex and body mass index. RNA sequencing confirmed upregulation of pro-inflammatory and proliferation-related genes during NP and identified novel processes, including increased cellular stress and DNA damage responses, which may reflect tissue trauma associated with SV harvesting. Proteomic analysis identified upregulated extracellular matrix-related and coagulation/thrombosis proteins and downregulated metabolic proteins. Spatial transcriptomics detected transdifferentiating VSMC in the intima on the day of harvesting and highlighted dynamic alterations in fibroblast and VSMC phenotype and behavior during NP. Specifically, we identified new cell subpopulations contributing to NP, including SPP1 + , LGALS3 + VSMC and MMP2 + , MMP14 + fibroblasts.

Conclusion

Dynamic alterations of gene and protein expression occur during NP in human SV. Identification of the human-specific molecular and cellular mechanisms may provide novel insight into SV bypass graft disease.

Osteopontin Activation and Microcalcification in Venous Grafts Can Be Modulated by Dexamethasone

BACKGROUND

Osteopontin has been implicated in vascular calcification formation and vein graft intimal hyperplasia, and its expression can be triggered by pro-inflammatory activation of cells. The role of osteopontin and the temporal formation of microcalcification in vein grafts is poorly understood with a lack of understanding of the interaction between haemodynamic changes and the activation of osteopontin.

METHODS

We used a porcine model of vein interposition grafts, and human long saphenous veins exposed to ex vivo perfusion, to study the activation of osteopontin using polymerase chain reaction, immunostaining, and 18F-sodium fluoride autoradiography.

RESULTS

The porcine model showed that osteopontin is active in grafts within 1 week following surgery and demonstrated the presence of microcalcification. A brief pretreatment of long saphenous veins with dexamethasone can suppress osteopontin activation. Prolonged culture of veins after exposure to acute arterial haemodynamics resulted in the formation of microcalcification but this was suppressed by pretreatment with dexamethasone. 18F-sodium fluoride uptake was significantly increased as early as 1 week in both models, and the pretreatment of long saphenous veins with dexamethasone was able to abolish its uptake.

CONCLUSIONS

Osteopontin is activated in vein grafts and is associated with microcalcification formation. A brief pretreatment of veins ex vivo with dexamethasone can suppress its activation and associated microcalcification.

The VEST External Support for Saphenous Vein Grafts in Coronary Surgery: A Review of Randomized Clinical Trials

Saphenous vein grafts (SVGs) are the most frequently used conduits in coronary artery bypass grafting (CABG), but their higher rate of occlusion compared to arterial conduits remains a concern. Previous studies have shown that SVG failure is mainly driven by intimal hyperplasia, an adaptative response to higher pressures of the arterial circulation. The VESTTM device (Vascular Graft Solutions, Tel Aviv, Israel), an external support designed to mitigate intimal hyperplasia in SVGs, has been tested in few clinical trials (RCTs). Herein, we descriptively evaluated the randomized evidence on the VEST device.

Subacute saphenous vein graft stent thrombosis due to unusual drug interaction: a case report

Background

Stent thrombosis is a potentially lethal complication of coronary angioplasty and responsible for 20% of all post-angioplasty myocardial infarctions. Unusual causes may be overlooked and difficult to identify.

Case summary

A 70-year-old male with history of triple aortocoronary bypass presented with acute inferolateral ST-segment elevation myocardial infarction (STEMI). Critical stenosis of the vein graft to the right coronary artery was revealed, and with the use of distal embolic protection device, successful angioplasty with stent was performed under double antiplatelet treatment with aspirin and ticagrelor. Two weeks later, he presented again at the emergency department with an acute inferolateral STEMI. Subacute stent thrombosis with complete occlusion of the stented vein graft was evident. Repeated balloon dilatations restored the flow stabilizing the patient; optical coherence tomography showed good stent expansion and apposition. Scrutinizing the patient's history, we discovered comedication with carbamazepine that is a CYP3A4 inducer and reduces ticagrelor's effect. Switching to prasugrel ensured potent antiplatelet treatment, and the patient was discharged 5 days later. The 6-month follow-up was uneventful and free of symptoms.

Discussion

Stent thrombosis has dire consequences, and the precipitating factors should always be investigated. Inadequate platelet inhibition secondary to non-compliance to therapy or resistance and suboptimal stent expansion/apposition are its main causes. Drug interactions are an underrecognized factor that may significantly alter the potency of antiplatelet drugs and also lead to stent thrombosis; thus, treatment is essential to be tailored to each patient comedication.

3D Elastomeric Stent Functionalized with Antioxidative and Perivascular Tissue Regenerative Activities Ameliorated PVT Deprivation-Induced Vein Graft Failure

Clinically, arterial injuries are always accompanied with perivascular tissue damage, which may contribute to high failure rate of vein grafts due to intimal hyperplasia and acute thrombosis. In this study, a "perivascular tissue (PVT) deprivation" animal model is constructed to mimic clinical scenarios and identify the contribution of arterial PVT to the success of vein grafts. Proteomics analysis suggests that depriving PVT may exacerbate reactive oxygen species (ROS)-induced endothelial apoptosis by up-regulating inflammation response and oxidative stress. Locally administering metformin on vein grafts through 3D-printed external stent (PGS-PCL) shows antioxidative and anti-inflammatory properties to protect cells from ROS invasion, thereafter decreasing acute thrombosis. Moreover, metformin induce rapid regeneration of perivascular adipose tissue in recipient regions, which improves patency by inhibiting intimal hyperplasia. Proteomics, western blot, and in vitro blocking tests reveal that metformin resists endothelial apoptosis through AMPK/mTOR and NFκB signaling pathways. To conclude, PVT deprivation exacerbates inflammatory response and oxidative stress in vein grafts bridging arterial circulation. Metformin-loaded stent ameliorates "PVT damage" related vein graft failure, and enhances patency of through resisting endothelial apoptosis and regenerating arterial PVAT, offering a promising avenue to improve the success of vein grafts in clinic.

Antiplatelet therapy around CABG: the latest evidence

PURPOSE OF REVIEW

The optimal antiplatelet strategy in patients after coronary artery bypass graft (CABG) surgery is unclear. We review the evidence on the efficacy and safety of DAPT after CABG and discuss potential novel antiplatelet strategies that reduce the risk of bleeding without loss of efficacy.

RECENT FINDINGS

Adding the potent P2Y12 inhibitor ticagrelor to aspirin for 1 year after CABG is associated with a reduction in the risk of vein graft failure, at the expense of an increased risk of clinically important bleeding. Ticagrelor monotherapy is not associated with better efficacy than aspirin alone, but is not associated with increased bleeding risk.

SUMMARY

Dual antiplatelet therapy (DAPT) is recommended after acute coronary syndrome events, but aspirin as single antiplatelet therapy remains the cornerstone of antithrombotic therapy in stable ischemic heart disease because of a lack of solid evidence on the benefit of DAPT on clinical outcomes. Shorter duration DAPT, based on the pathophysiology of vein graft failure, may be a promising strategy that requires testing in adequately powered randomized trials.

Intensive Lipid-Lowering Therapy as per the Latest Dyslipidemia Management Guideline in Predicting Favorable Long-Term Clinical Outcomes in Patients Undergoing Coronary Artery Bypass Grafting: A Retrospective Cohort Study

Background There are limited data on low-density lipoprotein cholesterol (LDL-C) goal achievement per the 2019 European Society of Cardiology/European Atherosclerosis Society dyslipidemia management guidelines and its impact on long-term outcomes in patients undergoing coronary artery bypass grafting (CABG). We investigated the association between LDL-C levels attained 1 year after CABG and the long-term outcomes. Methods and Results A total of 2072 patients diagnosed with multivessel coronary artery disease and undergoing CABG between 2011 and 2020 were included. Patients were categorized by lipid levels at 1 year after CABG, and the occurrence of major adverse cardiovascular and cerebrovascular events (MACCEs) was evaluated. The goal of LDL-C <1.40 mmol/L was attained in only 310 patients (14.9%). During a mean follow-up of 4.2 years after the index 1-year assessment, 25.0% of the patients experienced MACCEs. Multivariable-adjusted hazard ratios (95% CIs) for MACCEs, cardiac death, nonfatal myocardial infarction, nonfatal stroke, revascularization, and cardiac rehospitalization were 1.94 (1.41-2.67), 2.27 (1.29-3.99), 2.45 (1.55-3.88), 1.17 (0.63-2.21), 2.47 (1.31-4.66), and 1.87 (1.19-2.95), respectively, in patients with LDL-C ≥2.60 mmol/L, compared with patients with LDL-C <1.40 mmol/L. The LDL-C levels at 1-year post-CABG were independently associated with long-term MACCEs. Conclusions This retrospective analysis demonstrates that lipid goals are not attained in the vast majority of patients at 1 year after CABG, which is independently associated with the increased risk of long-term MACCEs. Further prospective, multicenter studies are warranted to validate if intensive lipid management could improve the outcomes of patients undergoing CABG.

Hemodynamics of vascular shunts: trends, challenges, and prospects

Vascular bypass surgery takes a significant place in the treatment of vascular disease. According to various assessments, this type of surgery is associated with almost 20 % of all vascular surgery episodes (up to 23 % according to the Federal Neurosurgical Center of Novosibirsk). Even though the problem of using of vascular grafts is obvious and natural, many problems associated with them are not still elucidated. From the mechanics' point of view, a vascular bypass is a converging or diverging tee, and the functioning of such structures still does not have strict mathematical formulations and proofs in the general case, which forces many researchers to solve specific engineering problems associated with shunting. Mathematical modeling, which is the gold standard for virtual simulations of industrial and medical problems, faces great difficulties and limitations in solving problems for vascular bypasses. Complications in the treatment of the vascular disease may follow the difficulties in mathematical modeling, and the price can be a cardiac arrest or a stroke. This work is devoted to the main aspects of the medical application of vascular bypasses and their functioning as a mechanical system, as well the mathematical aspects of their possible setup.

Apolipoprotein A-I vascular gene therapy reduces vein-graft atherosclerosis

Coronary artery venous bypass grafts typically fail because of atherosclerosis driven by lipid and macrophage accumulation. Therapy for vein-graft atherosclerosis is limited to statin drugs, which are only modestly effective. We hypothesized that transduction of vein-graft endothelium of fat-fed rabbits with a helper-dependent adenovirus expressing apolipoprotein AI (HDAdApoAI) would reduce lipid and macrophage accumulation. Fat-fed rabbits received bilateral external jugular vein-to-carotid artery interposition grafts. Four weeks later, one graft per rabbit (n = 23 rabbits) was infused with HDAdApoAI and the contralateral graft with HDAdNull. Grafts were harvested 12 weeks later. Paired analyses of grafts were performed, with vein graft cholesterol, intimal lipid, and macrophage content as the primary endpoints. HDAd genomes were detected in all grafts. APOAI mRNA was median 63-fold higher in HDAdApoAI grafts versus HDAdNull grafts (p < 0.001). HDAdApoAI grafts had a mean 15% lower total cholesterol (by mass spectrometry; p = 0.003); mean 19% lower intimal lipid (by oil red O staining; p = 0.02); and mean 13% lower expression of the macrophage marker CD68 (by reverse transcriptase-mediated quantitative PCR; p = 0.008). In vivo transduction of vein-graft endothelium achieves persistent APOAI expression and reduces vein-graft cholesterol, intimal lipid, and CD68 expression. Vascular gene therapy with APOAI has promise for preventing vein-graft failure caused by atherosclerosis.

Research on the Current Application Status of Magnesium Metal Stents in Human Luminal Cavities

The human body comprises various tubular structures that have essential functions in different bodily systems. These structures are responsible for transporting food, liquids, waste, and other substances throughout the body. However, factors such as inflammation, tumors, stones, infections, or the accumulation of substances can lead to the narrowing or blockage of these tubular structures, which can impair the normal function of the corresponding organs or tissues. To address luminal obstructions, stenting is a commonly used treatment. However, to minimize complications associated with the long-term implantation of permanent stents, there is an increasing demand for biodegradable stents (BDS). Magnesium (Mg) metal is an exceptional choice for creating BDS due to its degradability, good mechanical properties, and biocompatibility. Currently, the Magmaris® coronary stents and UNITY-BTM biliary stent have obtained Conformité Européene (CE) certification. Moreover, there are several other types of stents undergoing research and development as well as clinical trials. In this review, we discuss the required degradation cycle and the specific properties (anti-inflammatory effect, antibacterial effect, etc.) of BDS in different lumen areas based on the biocompatibility and degradability of currently available magnesium-based scaffolds. We also offer potential insights into the future development of BDS.

BRD4770 inhibits vascular smooth muscle cell proliferation via SUV39H2, but not EHMT2 to protect against neointima formation

The behavior of vascular smooth muscle cells (VSMCs) contributes to the formation of neointima. We previously found that EHMT2 suppressed autophagy activation in VSMCs. BRD4770, an inhibitor of EHMT2/G9a, plays a critical role in several kinds of cancers. However, whether and how BRD4770 regulates the behavior of VSMCs remain unknown. In this study, we evaluate the cellular effect of BRD4770 on VSMCs by series of experiments in vivo and ex vivo. We demonstrated that BRD4770 inhibited VSMCs' growth by blockage in G2/M phase in VSMCs. Moreover, our results demonstrated that the inhibition of proliferation was independent on autophagy or EHMT2 suppression which we previous reported. Mechanistically, BRD4770 exhibited an off-target effect from EHMT2 and our further study reveal that the proliferation inhibitory effect by BRD4770 was associated with suppressing on SUV39H2/KTM1B. In vivo, BRD4770 was also verified to rescue VIH. Thus, BRD4770 function as a crucial negative regulator of VSMC proliferation via SUV39H2 and G2/M cell cycle arrest and BRD4770 could be a molecule for the therapy of vascular restenosis.

Effects of different preservation schemes on isolated rat artery

Allogeneic blood vessels are regarded as one of the best natural substitutes for diseased blood vessels due to their good vascular compliance and histocompatibility. Since the supply and demand of allograft blood vessels do not always match in time and space, a good preservation scheme for isolated blood vessels is essential. The abdominal aortas of 110 male Sprague-Dawley (SD) rats were randomly divided into three groups, including cold storage group (4°C) (CSG), frozen storage group (FSG) and ambient storage group (25 ± 2°C) (ASG). Seven time points of preservation for 1, 3, 5, 7, 14, 30 and 90 days were set for detection. The changes in vascular physiological function were evaluated by MTT test and vasoconstriction ability detection, and the changes in vascular wall structure were evaluated by the tension tolerance test and pathological staining. The vascular function of CSG was better than FSG within first the 7 days, but the result was opposite since the 14th day. The vascular wall structure, collagen and elastic fibres of vessels, in CSG, showed oedema within 30 days, and continuous disintegration and rupture at 90 days. The vessel wall structure of FSG remained intact within 90 days. The tensile strength of the vessels in CSG was better than that in FSG within 5 days, and there was no statistical difference between the two groups between the 7th and 30th day, and then, the FSG was higher than CSG on the 90th day. Both cold storage and frozen storage could be applied as safe and effective preservation schemes for isolated rat artery within first 30 days. Cold storage is recommended when the storage time is <14 days, and then, frozen storage is better.

Relationship between systemic immune-inflammation index and no-reflow in percutaneous coronary intervention for saphenous grafts

Objective: In this study, we investigated the occurrence of no-reflow (NR) in percutaneous coronary intervention (PCI) for saphenous vein grafts (SVGs) and its relationship with a new systemic immune-inflammation index (SII) that determines inflammation. Methods: We studied 303 patients with acute coronary syndrome without ST elevation who underwent PCI for SVG disease. Results: NR formation during SVG PCI was significantly higher in patients with high SII (p < 0.001). NR occurrence was 12.8% when SII was ≤548 and 41.9% when SII was >548. Conclusion: Our study is the first to investigate SII as the state of inflammation and its effect on the SVG PCI. Patients with higher SII have a higher risk of NR during an SVG for PCI.

Pathophysiology and management of saphenous vein graft disease

INTRODUCTION

The saphenous vein graft (SVG) is the most used conduit in CABG. With standardization of its use as a conduit came an understanding of its accelerated atherosclerosis, known as saphenous vein graft disease (SVGD). Given its extensive use, a review of the pathophysiology and management of SVGD is important as we optimize its use.

AREAS COVERED

For this review, an extensive literature search was completed to identify and examine the evolution of SVG in CABG, mechanisms driving SVGD, and methods developed to prevent and manage it. This includes a review of relevant major papers and trials in this space.

EXPERT OPINION

Eras of evolution in SVG usage in CABG include an experimental era, era of SVG dominance in CABG, and the current era of mixed venous and arterial grafting. As SVGD was studied, the mechanisms behind it became more understood, and prevention and management methods were developed. As advances in surgical techniques and pharmacotherapy continue to reduce occurrence and severity of SVGD, long-term patency of SV grafts continues to improve and remain excellent in optimized settings. With continued innovation and improvement in operative techniques, the SVG conduit is and will remain an important player in the field of coronary bypass.

The Role of TGF-β Signaling in Saphenous Vein Graft Failure after Peripheral Arterial Disease Bypass Surgery

Saphenous vein bypass grafting is an effective technique used to treat peripheral arterial disease (PAD). However, restenosis is the major clinical challenge for the graft vessel among people with PAD postoperation. We hypothesize that there is a common culprit behind arterial occlusion and graft restenosis. To investigate this hypothesis, we found TGF-β, a gene specifically upregulated in PAD arteries, by bioinformatics analysis. TGF-β has a wide range of biological activities and plays an important role in vascular remodeling. We discuss the molecular pathway of TGF-β and elucidate its mechanism in vascular remodeling and intimal hyperplasia, including EMT, extracellular matrix deposition, and fibrosis, which are the important pathways contributing to stenosis. Additionally, we present a case report of a patient with graft restenosis linked to the TGF-β pathway. Finally, we discuss the potential applications of targeting the TGF-β pathway in the clinic to improve the long-term patency of vein grafts.

Inflachromene inhibits intimal hyperplasia through the HMGB1/2- regulated TLR4-NF-κB pathway

The contractile-syntheticphenotypicconversion of vascular smooth muscle cells (VSMCs) plays a key role in atherosclerosis, vascular restenosis, and hypertension. Our previous study explored the correlation between high mobility group box protein (HMGB) 1 and HMGB2 and neointimal hyperplasia after vascular injury. In the present study, we explore whether inflachromene (ICM), a novel inhibitor of the expression of both HMGB1 and HMGB2, modulates phenotypic changes in VSMCs and the mechanisms involved. Mice treated with ICM after carotid artery wire injury showed a decrease in excessive neointimal hyperplasia compared with that in the vehicle groups. In cultured VSMCs, pretreatment with ICM suppressed the angiotensin II (Ang II)-induced phenotypic conversion, proliferation, and migration. We discovered that ICM reduced the Ang II-induced upregulation of the expression of HMGB1 and HMGB2 and inhibited their shuttling between the nucleus and the cytosol. Mechanistically, Ang II-treated VSMCs exhibited higher levels of Toll-like receptor 4 (TLR4) and nuclear factor-κB (NF-κB) phosphorylation, which were attenuated by ICM. In addition, the NF-κB inhibitor Bay-117082 abolished the recombinant HMGB1-mediated VSMC phenotypic conversion, proliferation, and migration. Furthermore, ICM ameliorated the Ang II-induced increases in NAD[P]H oxidase expression, thereby attenuating the Ang II-induced proliferation and migration. These results reveal that ICM pretreatment attenuates Ang II-induced VSMC dedifferentiation, proliferation, and migration may by regulating the TLR4-NF-kB pathway. Thus, ICM is a potential therapy and preventive treatment for vascular proliferative diseases.

Prevention of anastomotic stenosis for decellularized vascular grafts using rapamycin-loaded boronic acid-based hydrogels mimicking the perivascular tissue function

Abnormal proliferation of vascular smooth muscle cells (VSMCs) induces graft anastomotic stenosis, resulting in graft failure. Herein, we developed a drug-loaded tissue-adhesive hydrogel as artificial perivascular tissue to suppress VSMCs proliferation. Rapamycin (RPM), an anti-stenosis drug, is selected as the drug model. The hydrogel was composed of poly (3-acrylamidophenylboronic acid-co-acrylamide) (BAAm) and polyvinyl alcohol. Since phenylboronic acid reportedly binds to sialic acid of glycoproteins which is distributed on the tissues, the hydrogel is expected to be adherent to the vascular adventitia. Two hydrogels containing 25 or 50 mg/mL of BAAm (BAVA25 and BAVA50, respectively) were prepared. A decellularized vascular graft with a diameter of <2.5 mm was selected as a graft model. Lap-shear test indicates that both hydrogels adhered to the graft adventitia. In vitro release test indicated that 83 and 73 % of RPM in BAVA25 and BAVA50 hydrogels was released after 24 h, respectively. When VSMCs were cultured with RPM-loaded BAVA hydrogels, their proliferation was suppressed at an earlier stage in RPM-loaded BAVA25 hydrogels compared to RPM-loaded BAVA50 hydrogels. An in vivo preliminary test reveals that the graft coated with RPM-loaded BAVA25 hydrogel shows better graft patency for at least 180 d than the graft coated with RPM-loaded BAVA50 hydrogel or without hydrogel. Our results suggest that RPM-loaded BAVA25 hydrogel with tissue adhesive characteristics has potential to improve decellularized vascular graft patency.

Graft thrombosis after coronary artery bypass surgery and current practice for prevention

Coronary artery bypass grafting (CABG) is the most frequently performed cardiac surgery worldwide. The reported incidence of graft failure ranges between 10% and 50%, depending upon the type of conduit used. Thrombosis is the predominant mechanism of early graft failure, occurring in both arterial and vein grafts. Significant advances have been made in the field of antithrombotic therapy since the introduction of aspirin, which is regarded as the cornerstone of antithrombotic therapy for prevention of graft thrombosis. Convincing evidence now exists that dual antiplatelet therapy (DAPT), consisting of aspirin and a potent oral P2Y12 inhibitor, effectively reduces the incidence of graft failure. However, this is achieved at the expense of an increase in clinically important bleeding, underscoring the importance of balancing thrombotic risk and bleeding risk when considering antithrombotic therapy after CABG. In contrast, anticoagulant therapy has proved ineffective at reducing the occurrence of graft thrombosis, pointing to platelet aggregation as the key driver of graft thrombosis. We provide a comprehensive review of current practice for prevention of graft thrombosis and discuss potential future concepts for antithrombotic therapy including P2Y12 inhibitor monotherapy and short-term DAPT.

The Role of Preservation Solutions upon Saphenous Vein Endothelial Integrity and Function: Systematic Review and UK Practice Survey

The long saphenous vein is the most used conduit in cardiac surgery, but its long-term patency is limited by vein graft disease (VGD). Endothelial dysfunction is a key driver of VGD; its aetiology is multi-factorial. However emerging evidence identifies vein conduit harvest technique and preservation fluids as causal in their onset and propagation. This study aims to comprehensively review published data on the relationship between preservation solutions, endothelial cell integrity and function, and VGD in human saphenous veins harvested for CABG. The review was registered with PROSPERO (CRD42022358828). Electronic searches of Cochrane Central Register of Controlled Trials, MEDLINE, and EMBASE databases were undertaken from inception until August 2022. Papers were evaluated in line with registered inclusion and exclusion criteria. Searches identified 13 prospective, controlled studies for inclusion in the analysis. All studies used saline as a control solution. Intervention solutions included heparinised whole blood and saline, DuraGraft, TiProtec, EuroCollins, University of Wisconsin (UoW), buffered, cardioplegic and Pyruvate solutions. Most studies demonstrated that normal saline appears to have negative effects on venous endothelium and the most effective preservation solutions identified in this review were TiProtec and DuraGraft. The most used preservation solutions in the UK are heparinised saline or autologous whole blood. There is substantial heterogeneity both in practice and reporting of trials evaluating vein graft preservation solutions, and the quality of existing evidence is low. There is an unmet need for high quality trials evaluating the potential for these interventions to improve long-term patency in venous bypass grafts.

A Travel Through Time

Managing coronary saphenous vein graft failure has remained an unmet need since the inception of interventional cardiology. The present case constitutes an opportunity to revisit percutaneous strategies to treat saphenous vein graft failure, providing a travel though interventional strategies and showing a contemporary approach to this problem. (Level of Difficulty: Intermediate.).

Characteristics of Radial Artery Coronary Bypass Graft Failure and Outcomes Following Subsequent Percutaneous Coronary Intervention

BACKGROUND

When patients with prior coronary artery bypass grafting (CABG) undergo percutaneous coronary intervention (PCI), targeting the native vessel is preferred. Studies informing such recommendations are based predominantly on saphenous vein graft (SVG) PCI. There are few data regarding arterial graft intervention, particularly to a radial artery (RA) graft.

OBJECTIVES

The aim of this study was to report the characteristics of arterial graft stenoses and evaluate the feasibility of RA PCI.

METHODS

This study included 2,780 consecutive patients with prior CABG undergoing PCI between 2005 and 2018 who were prospectively enrolled in the MIG (Melbourne Interventional Group) registry. Data were stratified by PCI target vessel. RA graft PCI was compared with both native vessel (native PCI) and SVG PCI. Internal mammary graft PCI data were reported. The primary outcome was 3-year mortality.

RESULTS

Overall, 1,928 patients (69.4%) underwent native PCI, 716 (25.6%) SVG PCI, 86 (3.1%) RA PCI, and 50 (1.8%) internal mammary graft PCI. Compared with SVG PCI, the RA PCI cohort presented earlier after CABG, less frequently had acute coronary syndrome, and more commonly had ostial or distal anastomosis intervention (P < 0.005 for all). Compared with patients who underwent native PCI, those who underwent RA PCI were more likely to have diabetes and peripheral vascular disease (P < 0.001 for both) and to present with non-ST-segment elevation myocardial infarction (P = 0.010). The RA PCI group had no perforations or in-hospital myocardial infarctions, though no significant difference was found in periprocedural outcomes compared with either native or SVG PCI. No differences were found between RA PCI and either native or SVG PCI in 30-day outcomes or 3-year mortality.

CONCLUSIONS

Presenting and lesion characteristics differed between patients undergoing arterial compared with SVG PCI, implying a varied pathogenesis of graft stenosis. RA PCI appears feasible, safe, and where anatomically suitable, may be a viable alternative to native PCI.

Genetic Variants in PHACTR1 & LPL Mediate Restenosis Risk in Coronary Artery Patients

Background and Objective

Coronary artery disease (CAD) is a major cause of death worldwide. Revascularization via stent placement or coronary artery bypass grafting (CABG) are standard treatments for CAD. Despite a high success rate, these approaches are associated with long-term failure due to restenosis. Risk factors associated with restenosis were investigated using a case-control association study design.

Methods

Five thousand two hundred and forty-two patients were enrolled in this study and were assigned as follows: Stenosis Group: 3570 patients with CAD >50% without a prior stent or CABG (1394 genotyped), and Restenosis Group: 1672 patients with CAD >50% and prior stent deployment or CABG (705 genotyped). Binomial regression models were applied to investigate the association of restenosis with diabetes, hypertension, and dyslipidemia. The genetic association with restenosis was conducted using PLINK 1.9.

Results

Dyslipidemia is a major risk factor (Odds Ratio (OR) = 2.14, P-value <0.0001) for restenosis particularly among men (OR = 2.32, P < 0.0001), while type 2 diabetes (T2D) was associated with an increased risk of restenosis in women (OR = 1.36, P = 0.01). The rs9349379 (PHACTR1) and rs264 (LPL) were associated with an increased risk of restenosis in our patients. PHACTR1 variant was associated with increased risk of restenosis mainly in women and in diabetic patients, while the LPL variant was associated with increased risk of restenosis in men.

Conclusion

The rs9349379 in PHACTR1 gene is significantly associated with restenosis, this association is more pronounced in women and in diabetic patients. The rs264 in LPL gene was associated with increased risk of restenosis in male patients.

Oscillatory shear stress promotes vein graft intimal hyperplasia via NADPH oxidase-related pathways

Background

Uncontrolled intimal hyperplasia (IH) after autologous saphenous vein grafting triggers a high restenosis rate; however, its association with the activation of NADPH oxidase (NOX)-related pathways is unclear. Here, we investigated the effects and mechanism of oscillatory shear stress (OSS) on grafted vein IH.

Methods

Thirty male New Zealand rabbits were randomly divided into control, high-OSS (HOSS), and low-OSS (LOSS) groups, and the vein grafts were harvested after 4 weeks. Hematoxylin and eosin staining and Masson staining assays were used to observe morphological and structural changes. Immunohistochemical staining was used to detect α-SMA, PCNA, MMP-2, and MMP-9 expression. Immunofluorescence staining was used to observe reactive oxygen species (ROS) production in the tissues. Western blotting was used to determine the expression levels of pathway-related proteins (NOX1, NOX2, AKT, p-AKT, and BIRC5), PCNA, BCL-2, BAX, and caspase-3/cleaved caspase-3 in tissues.

Results

Blood flow velocity was lower in the LOSS group than in the HOSS group, while vessel diameter did not change significantly. Shear rate was elevated in both HOSS and LOSS groups but was higher in the HOSS group. Additionally, vessel diameter increased with time in the HOSS and LOSS groups, whereas flow velocity did not. Intimal hyperplasia was significantly lower in the LOSS group than in the HOSS group. IH was dominated by smooth muscle fibers in the grafted veins and collagen fibers in the media. OSS restriction significantly reduced the α-SMA, PCNA, MMP-2, and MMP-9 levels. Moreover, ROS production and the expression of NOX1, NOX2, p-AKT, BIRC5, PCNA, BCL-2, BAX, and cleaved caspase-3 were phase-reduced in LOSS compared to the levels in the HOSS group. Total AKT was not differentially expressed among the three groups.

Conclusion

OSS promotes the proliferation, migration, and survival of subendothelial vascular smooth muscle cells in grafted veins, which may be related to the regulation of downstream p-AKT/BIRC5 levels through the increased production of ROS by NOX. Drugs inhibiting this pathway might be used to prolong vein graft survival time.

Endoplasmic Reticulum Stress-induced Endothelial Dysfunction Promotes Neointima Formation after Arteriovenous Grafts in Mice on High-fat Diet

OBJECTIVE

Endothelial dysfunction is one candidate for triggering neointima formation after arteriovenous grafts (AVGs), but the factors mediating this process are unclear. The purpose of this study was to investigate the role of endoplasmic reticulum stress (ERS)-induced endothelial dysfunction in neointima formation following AVGs in high-fat diet (HFD) mice.

METHODS

CCAAT-enhancer-binding protein-homologous protein (CHOP) knockout (KO) mice were created. Mice were fed with HFD to produce HFD model. AVGs model were applied in the groups of WT ND, WT HFD, and CHOP KO HFD. Human umbilical vein endothelial cells (HUVECs) were cultured with oxidized low density lipoprotein (ox-LDL) (40 mg/L) for the indicated time lengths (0, 6, 12, 24 h). ERS inhibitor tauroursodeoxycholic acid (TUDCA) was used to block ERS. Immunohistochemical staining was used to observe the changes of ICAM1. Changes of ERS were detected by real-time RT-PCR. Protein expression levels and ERS activation were detected by Western blotting. Endothellial cell function was determined by endothelial permeability assay and transendothelial migration assay.

RESULTS

HFD increased neointima formation in AVGs associated with endothelial dysfunction. At the same time, ERS was increased in endothelial cells (ECs) after AVGs in mice consuming the HFD. In vitro, ox-LDL was found to stimulate ERS, increase the permeability of the EC monolayer, and cause endothelial dysfunction. Blocking ERS with TUDCA or CHOP siRNA reversed the EC dysfunction caused by ox-LDL. In vivo, knockout of CHOP (CHOP KO) protected the function of ECs and decreased neointima formation after AVGs in HFD mice.

CONCLUSION

Inhibiting ERS in ECs could improve the function of AVGs.

Early Saphenous Vein Graft Aneurysm Rupture: A Not So-Late Complication. Case Report and Comprehensive Literature Review

BACKGROUND AND OBJECTIVES

Saphenous vein graft (SVG) is a cardiac surgical practice used to create a cardiac bypass in cases of coronary artery obstruction. It consists of a surgical procedure that involves the creation of an aorto-coronary communication by a venous conduit (saphenous vein) to bypass coronary stenosis and allow cardiac revascularization. This practice can be affected by early and late complications. The most feared complication is graft aneurysm or pseudoaneurysm degeneration and rupture which are considered late complications. This paper presents a rare case of SVG aneurysmal rupture that occurred 24 h after surgery and a review of the literature to provide a general look at the state of knowledge.

MATERIALS AND METHODS

The systematic review was carried out using the guidelines according to the PRISMA method.

RESULTS

Cases of aneurysmal rupture have never been described prior to one month after surgery. The male sex and subjects under 45 are the most affected by this complication. Death occurs in less than half of the cases, being more frequent in young people. Performing a CT or angio-CT examination led to the diagnosis.

CONCLUSIONS

It is impossible to estimate the implanted vessel's quality, so postoperative follow-up is fundamental. Transesophageal ultrasound can be useful, and hematochemical tests are valuable early diagnostic tools, whrease CT and angio-CT can be useful even months after surgery. Forensic analysis should always perform an autopsy and graft histological examination.

Filter-based embolic protection device in saphenous vein graft percutaneous intervention: A case report

Saphenous vein grafts (SVGs) are commonly used in coronary artery bypass graft (CABG) surgery patients. However, SVGs are prone to degradation and occlusion, resulting in poor long-term patency. Percutaneous coronary intervention (PCI) for SVG has been one of the options to treat SVGs disease despite its challenges. Embolic protection device (EPD) use along with proper stent and medications are considered to minimize complications in this procedure. A 61-year-old man, with 4-vessel coronary artery bypass using SVGs and left internal mammary artery (LIMA) 11 years ago, presented with chest pain for more than 3 months. Coronary angiography showed severe stenosis of the SVG to PDA with two lesions, chronic total occlusion in SVG to OM and LIMA to LAD, with patent SVG to D1. He was admitted for elective PCI using drug-eluting stents and distal embolic filter. There were no problems observed, and the procedure was completed with successful stenting in SVG to PDA without any complications. The patient was discharged on dual-antiplatelet therapy along with his previous medication history. PCI is preferred over repeated CABG in high-risk patients, and EPD should be considered whenever technically possible to minimize the risk of distal embolization and thereby improve outcomes in SVG PCI.

Late Saphenous Vein Graft Disease: Cut to the Chase

We read with interest the article entitled “The Role of Systemic Immune Inflammation Index for Predicting Saphenous Vein Graft Disease in Patients with Coronary Artery Bypass Grafting.” We congratulate the authors for their contribution. We would like to discuss some points about the late development of saphenous vein graft disease.

A novel Nanocellulose-Gelatin-AS-IV external stent resists EndMT by activating autophagy to prevent restenosis of grafts

Vein grafts are widely used for coronary artery bypass grafting and hemodialysis access, but restenosis remains the "Achilles' heel" of these treatments. An extravascular stent is one wrapped around the vein graft and provides mechanical strength; it can buffer high arterial pressure and secondary vascular dilation of the vein to prevent restenosis. In this study, we developed a novel Nanocellulose-gelatin hydrogel, loaded with the drug Astragaloside IV (AS-IV) as an extravascular scaffold to investigate its ability to reduce restenosis. We found that the excellent physical and chemical properties of the drug AS-IV loaded Nanocellulose-gelatin hydrogel external stent limit graft vein expansion and make the stent biocompatible. We also found it can prevent restenosis by resisting endothelial-to-mesenchymal transition (EndMT) in vitro. It does so by activating autophagy, and AS-IV can enhance this effect both in vivo and in vitro. This study has added to existing research on the mechanism of extravascular stents in preventing restenosis of grafted veins. Furthermore, we have developed a novel extravascular stent for the prevention and treatment of restenosis. This will help optimize the clinical treatment plan of external stents and improve the prognosis in patients with vein grafts.

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The NC-Gelatin extravascular stent has suitable physicochemical properties to prevent restenosis of the grafted veins.

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The NC-Gelatin extravascular stent has excellent biocompatibility, which is critical for grafting veins.

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The NC-Gelatin extravascular stent prevents restenosis by activating autophagy against EndMT.

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AS-IV can enhance the effect of the stent to activate autophagy against EndMT.

Saphenous Vein Graft Intervention

Even though saphenous vein grafts (SVGs) are the most commonly used surgical conduits, their long-term patency is limited by accelerated atherosclerosis often resulting in acute coronary syndrome or asymptomatic occlusion. SVG intervention is associated with 2 significant challenges: a significant risk of distal embolization with resultant periprocedural myocardial infarction in the short-term and restenosis in the long-term. Several individual trials have compared bare metal stents with drug-eluting stents for SVG intervention. This review article discusses the pathophysiology of SVG lesions, indications for SVG intervention, and the challenges encountered, and also technical considerations for SVG intervention and the supporting evidence.

Predictors of vein graft disease progression between one week and one year after surgical coronary revascularization: Impact of secondary prevention medications

OBJECTIVE

This study aimed to detect the predictors of vein graft disease (VGD) progression between 1 week and 1 year after surgery and to evaluate the impact of secondary prevention medications.

METHODS

A total of 218 consecutive patients underwent surgical coronary revascularization were evaluated by coronary computed tomography angiography both at 1-week and 1-year follow-up. Logistic regression analyses were performed to investigate the predictors of VGD progression. A risk score (0-4) was set up to evaluate implementation result of secondary prevention measures according to 1-year follow-up result. Association between VGD progression and the risk score was assessed.

RESULTS

VGD progression occurred in 11.3% of saphenous vein grafts (SVG) and 22.1% of patients. At the patient level, poor vein graft (odds ratio [OR] = 4.25), noncontrolled hyperlipidemia (OR = 3.01), and diabetes mellitus (DM) (OR = 2.96) were predictors, while diameter of SVG (mm, OR = 0.35) was protective factor. At the graft level, DM (OR = 3.52), noncontrolled hyperlipidemia (OR = 2.33), and peripheral artery disease (PAD) (OR = 2.20) were predictors, while number of SVGs (OR = 0.63), diameter of SVG (mm, OR = 0.39), and mean graft flow >25 ml/min (OR = 0.35) were protective factors. VGD progression was significantly associated with the risk score at both the patient (OR = 1.52) and the graft level (OR = 1.38).

CONCLUSIONS

Poor vein graft, noncontrolled hyperlipidemia and DM were predictors of VGD progression between 1 week and 1 year after surgery at the patient level, while larger SVG diameter was a protective factor. DM, PAD and noncontrolled hyperlipidemia were predictors at the graft level, while a number of SVGs, larger SVG diameter, and mean graft flow >25 ml/min were protective factors. Implementation failure of secondary prevention medications was associated with VGD progression from as early as 1 year after surgery.

Association of Dual Antiplatelet Therapy With Ticagrelor With Vein Graft Failure After Coronary Artery Bypass Graft Surgery: A Systematic Review and Meta-analysis

IMPORTANCE

The role of ticagrelor with or without aspirin after coronary artery bypass graft surgery remains unclear.

OBJECTIVE

To compare the risks of vein graft failure and bleeding associated with ticagrelor dual antiplatelet therapy (DAPT) or ticagrelor monotherapy vs aspirin among patients undergoing coronary artery bypass graft surgery.

DATA SOURCES

MEDLINE, Embase, and Cochrane Library databases from inception to June 1, 2022, without language restriction.

STUDY SELECTION

Randomized clinical trials (RCTs) comparing the effects of ticagrelor DAPT or ticagrelor monotherapy vs aspirin on saphenous vein graft failure.

DATA EXTRACTION AND SYNTHESIS

Individual patient data provided by each trial were synthesized into a combined data set for independent analysis. Multilevel logistic regression models were used.

MAIN OUTCOMES AND MEASURES

The primary analysis assessed the incidence of saphenous vein graft failure per graft (primary outcome) in RCTs comparing ticagrelor DAPT with aspirin. Secondary outcomes were saphenous vein graft failure per patient and Bleeding Academic Research Consortium (BARC) type 2, 3, or 5 bleeding events. A supplementary analysis included RCTs comparing ticagrelor monotherapy with aspirin.

RESULTS

A total of 4 RCTs were included in the meta-analysis, involving 1316 patients and 1668 saphenous vein grafts. Of the 871 patients in the primary analysis, 435 received ticagrelor DAPT (median age, 67 years [IQR, 60-72 years]; 65 women [14.9%]; 370 men [85.1%]) and 436 received aspirin (median age, 66 years [IQR, 61-73 years]; 63 women [14.5%]; 373 men [85.5%]). Ticagrelor DAPT was associated with a significantly lower incidence of saphenous vein graft failure (11.2%) per graft than was aspirin (20%; difference, -8.7% [95% CI, -13.5% to -3.9%]; OR, 0.51 [95% CI, 0.35 to 0.74]; P < .001) and was associated with a significantly lower incidence of saphenous vein graft failure per patient (13.2% vs 23.0%, difference, -9.7% [95% CI, -14.9% to -4.4%]; OR, 0.51 [95% CI, 0.35 to 0.74]; P < .001). Ticagrelor DAPT (22.1%) was associated with a significantly higher incidence of BARC type 2, 3, or 5 bleeding events than was aspirin (8.7%; difference, 13.3% [95% CI, 8.6% to 18.0%]; OR, 2.98 [95% CI, 1.99 to 4.47]; P < .001), but not BARC type 3 or 5 bleeding events (1.8% vs 1.8%, difference, 0% [95% CI, -1.8% to 1.8%]; OR, 1.00 [95% CI, 0.37 to 2.69]; P = .99). Compared with aspirin, ticagrelor monotherapy was not significantly associated with saphenous vein graft failure (19.3% vs 21.7%, difference, -2.6% [95% CI, -9.1% to 3.9%]; OR, 0.86 [95% CI, 0.58 to 1.27]; P = .44) or BARC type 2, 3, or 5 bleeding events (8.9% vs 7.3%, difference, 1.7% [95% CI, -2.8% to 6.1%]; OR, 1.25 [95% CI, 0.69 to 2.29]; P = .46).

CONCLUSIONS AND RELEVANCE

Among patients undergoing coronary artery bypass graft surgery, adding ticagrelor to aspirin was associated with a significantly decreased risk of vein graft failure. However, this was accompanied by a significantly increased risk of clinically important bleeding.