Mechanisms, Consequences, and Prevention of Coronary Graft Failure

Improving diversity in cardiac surgery clinical trials with ROMA:Women as an exemplar

PURPOSE OF REVIEW

To describe methods to improve representation of women in cardiac surgery clinical trials.

RECENT FINDINGS

Cardiovascular disease risk among women is high. Historically, women have been excluded from cardiac surgery trials, in part due to restrictive inclusion criteria. Surgical outcomes, specifically after coronary artery bypass grafting, are consistently worse among female patients, and these outcomes have not improved over the last decade. Addressing treatment effects and clinical benefit among women requires accurate representation in cardiovascular surgery trials. ROMA:Women, is the first cardiac surgery trial to focus solely on women, with the goal of addressing underrepresentation. Through utilizing specific strategies, ROMA:Women is a promising first step in advancing health equity.

SUMMARY

Strategies to ensure effective recruitment and representation among women in cardiac surgery clinical trials, such as tailored eligibility criteria and comprehensive strategies to improve communication and increase trust, are two of many potential approaches to address the structural barriers to female representation in cardiac surgery clinical trials. To date, ROMA:Women is an example of a trial that has shown extraordinary preliminary success enrolling women. Designing trials exclusively for women is one strategy to improve the diversity of clinical trial participation.

Level of Perivascular Inflammation Is Significantly Lower Around the Left Internal Mammary Artery Than Around Native Coronary Arteries

BACKGROUND

The left internal mammary artery (LIMA) is protected from developing atherosclerosis. Perivascular inflammation, which is closely associated with atherosclerosis, can be measured by perivascular adipose tissue attenuation on computed tomography angiography. Whether the absence of atherosclerosis in LIMA is related to the lower level of perivascular inflammation is unknown. This study was performed to compare the level of perivascular inflammation between LIMA in situ and native coronary arteries in patients with coronary artery disease.

METHODS AND RESULTS

A total of 573 patients who underwent both computed tomography angiography and optical coherence tomography imaging were included. The level of perivascular adipose tissue attenuation between LIMA in situ and coronary arteries was compared. Perivascular adipose tissue attenuation around LIMA in situ was significantly lower around the 3 coronary arteries (-82.9 [-87.3 to -78.0] versus -70.8 [-75.9 to -65.9]; P<0.001), irrespective of the level of pericoronary inflammation or the number of vulnerable features on optical coherence tomography. When patients were divided into high and low pericoronary inflammation groups, those in the high inflammation group had more target vessel failure (hazard ratio, 2.97 [95% CI, 1.16-7.59]; P=0.017).

CONCLUSIONS

The current study demonstrated that perivascular adipose tissue attenuation was significantly lower around LIMA in situ than around native coronary arteries. The lower level of perivascular inflammation may be related to the low prevalence of atherosclerosis in LIMA.

REGISTRATION

URL: https://www.clinicaltrials.gov; Unique Identifier: NCT04523194.

Native coronary artery or bypass graft percutaneous coronary intervention in patients after previous coronary artery bypass surgery: A large nationwide analysis from the Netherlands Heart Registration

BACKGROUND

Patients with previous coronary artery bypass surgery (CABG) who require repeat revascularization frequently undergo percutaneous coronary intervention (PCI). We sought to identify factors associated with the decision to intervene on the native vessel versus a bypass graft and investigate their outcomes in a large nationwide prospective registry.

METHODS

We identified patients who underwent PCI with a history of prior CABG from the Netherlands Heart Registration between 2017 and 2021 and stratified them by isolated native vessel PCI versus PCI including at least one venous- or arterial graft. The primary endpoint of major adverse cardiac events (MACE) was a composite of all-cause death and target vessel revascularization (TVR) at one-year post PCI. The key secondary endpoint was a composite of all-cause death, myocardial infarction (MI), and TVR at 30 days.

RESULTS

Out of 154,146 patients who underwent PCI, 12,822 (8.3%) had a prior CABG. Isolated native vessel PCI was most frequently performed (75.2%), while an acute coronary syndrome (ACS) presentation was most strongly associated with graft interventions. The primary outcome of MACE at one-year post PCI occurred more frequently in interventions including grafts compared with native vessels alone (19.7% vs. 14.3%; adjOR 1.267; 95% CI 1.101-1.457); p < 0.001) driven by TVR. There was however no difference in mortality or the key secondary endpoint between the two groups.

CONCLUSION

In this nationwide prospective registry, ACS presentation was strongly associated with bypass graft PCI. At one year after PCI, interventions including bypass grafts had a higher composite of MACE compared with isolated native vessel interventions.

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.

Safety outcomes of anti-platelet therapy post coronary artery bypass graft surgery: A systematic review and network meta-analysis of randomized control trials

BACKGROUND

Antiplatelet therapy is used to decrease the risk of graft failure post coronary artery bypass graft surgery. We aimed to compare dual antiplatelet therapy (DAPT) with monotherapy along with a comparison of Aspirin, Ticagrelor, Aspirin+Ticagrelor (A+T) and Aspirin+Clopidogrel (A+C) to determine the major and minor bleeding risk, risk of postoperative myocardial infarction (MI), stroke, and all-cause mortality (ACM).

METHODS

Randomized Controlled Trials comparing the four groups were included. Odds ratio (OR) and Absolute Risk (AR) were employed to assess the mean and standard deviation (SD) with 95% confidence intervals (CI). The Bayesian random-effects model was used for statistical analysis. Risk difference and Cochran Q tests were used to calculate rank probability (RP) and heterogeneity, respectively.

RESULTS

We included 10 trials, consisting of 21 arms and 3926 patients. For the risk of major and minor bleed, A + T and Ticagrelor showed the lowest mean value of 0.040 (0.043) and 0.067 (0.073), respectively, and the highest RP of being the safest group. While a direct comparison between DAPT and monotherapy resulted in an OR of 0.57 [0.34, 0.95] for the risk of minor bleed. A + T was found to have the highest RP and the lowest mean value in terms of ACM, MI, and stroke.

CONCLUSION

No significant difference was found between monotherapy or dual-antiplatelet therapy for the major bleeding risk safety outcome, however DAPT was found to have a significantly higher rate of minor bleeding complications post-CABG. DAPT should be considered as the antiplatelet modality of choice post-CABG.

Antithrombotic strategies for preventing graft failure in coronary artery bypass graft

Coronary artery bypass graft (CABG) procedures face challenges related to graft failure, driven by factors such as acute thrombosis, neointimal hyperplasia, and atherosclerotic plaque formation. Despite extensive efforts over four decades, the optimal antithrombotic strategy to prevent graft occlusion while minimizing bleeding risks remains uncertain, relying heavily on expert opinions rather than definitive guidelines. To address this uncertainty, we conducted a review of randomized clinical trials and meta-analyses of antithrombotic therapy for patients with CABG. These studies examined various antithrombotic regimens in CABG such as single antiplatelet therapy (aspirin or P2Y12 inhibitors), dual antiplatelet therapy, and anticoagulation therapy. We evaluated outcomes including the patency of grafts, major adverse cardiovascular events, and bleeding complications and also explored future perspectives to enhance long-term outcomes for CABG patients. Early studies established aspirin as a key component of antithrombotic pharmacotherapy after CABG. Subsequent randomized controlled trials focused on adding a P2Y12 inhibitor (such as clopidogrel, ticagrelor, or prasugrel) to aspirin, yielding mixed results. This article aims to inform clinical decision-making and guide the selection of antithrombotic strategies after CABG.

Long-term observational angiographic patency and perfect patency of radial artery compared with saphenous vein or internal mammary artery in coronary bypass surgery

OBJECTIVES

It is uncertain if the long-term biological behavior of the radial artery as a conduit for coronary bypass surgery has a similar resistance to the development of atherosclerosis as for the internal mammary artery. We aimed to examine long-term angiographic patency and disease-free patency (perfect patency) for internal mammary artery, radial artery, and saphenous vein grafts.

METHODS

A retrospective, single-center, individual patient cohort study of angiographic observations from patients' latest postoperative angiogram from 1997 to 2020 was performed. Analysis was per anastomosis and assessed for patency and perfect patency. A generalized linear mixed model premised upon logistic regression was used to minimize confounding bias.

RESULTS

A total of 983 patients with 3064 grafts were included, with a median follow-up of 8.6 (interquartile range, 4.4-12.6) years after the operation. Multivariable analysis revealed differences for radial (patency, 86.9%; perfect patency, 86.4%) and internal mammary artery (patency, 93.9%; perfect patency, 93.5%) versus saphenous vein graft (patency, 72.8%; perfect patency, 46.2%). There were no differences between the 2 arterial conduits for patency (odds ratio, 1.40; 95% CI, 0.85-2.33; P = .189) and perfect patency (odds ratio, 1.14; 95% CI, 0.71-1.84; P = .578). If a conduit was patent, then 99.4% of radial artery, 99.6% of internal mammary artery, and 63.5% of saphenous vein graft were reported as perfectly patent.

CONCLUSIONS

Radial artery and internal mammary artery had similar patency and perfect patency while both were superior to saphenous vein graft.

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).

Consensus statement-graft treatment in cardiovascular bypass graft surgery

Coronary artery bypass grafting (CABG) is and continues to be the preferred revascularization strategy in patients with multivessel disease. Graft selection has been shown to influence the outcomes following CABG. During the last almost 60 years saphenous vein grafts (SVG) together with the internal mammary artery have become the standard of care for patients undergoing CABG surgery. While there is little doubt about the benefits, the patency rates are constantly under debate. Despite its acknowledged limitations in terms of long-term patency due to intimal hyperplasia, the saphenous vein is still the most often used graft. Although reendothelialization occurs early postoperatively, the process of intimal hyperplasia remains irreversible. This is due in part to the persistence of high shear forces, the chronic localized inflammatory response, and the partial dysfunctionality of the regenerated endothelium. "No-Touch" harvesting techniques, specific storage solutions, pressure controlled graft flushing and external stenting are important and established methods aiming to overcome the process of intimal hyperplasia at different time levels. Still despite the known evidence these methods are not standard everywhere. The use of arterial grafts is another strategy to address the inferior SVG patency rates and to perform CABG with total arterial revascularization. Composite grafting, pharmacological agents as well as latest minimal invasive techniques aim in the same direction. To give guide and set standards all graft related topics for CABG are presented in this expert opinion document on graft treatment.

Impact of High Lipoprotein(a) on Long-Term Survival Following Coronary Artery Bypass Grafting

BACKGROUND

Lipoprotein(a) is a possible causal risk factor for atherosclerosis and related complications. The distribution and prognostic implication of lipoprotein(a) in patients undergoing coronary artery bypass grafting remain unknown. This study aimed to assess the impact of high lipoprotein(a) on the long-term prognosis of patients undergoing coronary artery bypass grafting.

METHODS AND RESULTS

Consecutive patients with stable coronary artery disease who underwent isolated coronary artery bypass grafting from January 2013 to December 2018 from a single-center cohort were included. The primary outcome was all-cause death. The secondary outcome was a composite of major adverse cardiovascular and cerebrovascular events. Of the 18 544 patients, 4072 (22.0%) were identified as the high-lipoprotein(a) group (≥50 mg/dL). During a median follow-up of 3.2 years, primary outcomes occurred in 587 patients. High lipoprotein(a) was associated with increased risk of all-cause death (high lipoprotein(a) versus low lipoprotein(a): adjusted hazard ratio [aHR], 1.31 [95% CI, 1.09-1.59]; P=0.005; lipoprotein(a) per 1-mg/dL increase: aHR, 1.003 [95% CI, 1.001-1.006]; P=0.011) and major adverse cardiovascular and cerebrovascular events (high lipoprotein(a) versus low lipoprotein(a): aHR, 1.18 [95% CI, 1.06-1.33]; P=0.004; lipoprotein(a) per 1-mg/dL increase: aHR, 1.002 [95% CI, 1.001-1.004]; P=0.002). The lipoprotein(a)-related risk was greater in patients with European System for Cardiac Operative Risk Evaluation <3, and tended to attenuate in patients receiving arterial grafts.

CONCLUSIONS

More than 1 in 5 patients with stable coronary artery disease who underwent coronary artery bypass grafting were exposed to high lipoprotein(a), which is associated with higher risks of death and major adverse cardiovascular and cerebrovascular events. The adverse effects of lipoprotein(a) were more pronounced in patients with clinically low-risk profiles or not receiving arterial grafts.

European Association of Cardio-Thoracic Surgery (EACTS) expert consensus statement on perioperative myocardial infarction after cardiac surgery

Cardiac surgery may lead to myocardial damage and release of cardiac biomarkers through various mechanisms such as cardiac manipulation, systemic inflammation, myocardial hypoxia, cardioplegic arrest and ischaemia caused by coronary or graft occlusion. Defining perioperative myocardial infarction (PMI) after cardiac surgery presents challenges, and the association between the current PMI definitions and postoperative outcomes remains uncertain. To address these challenges, the European Association of Cardio-Thoracic Surgery (EACTS) facilitated collaboration among a multidisciplinary group to evaluate the existing evidence on the mechanisms, diagnosis and prognostic implications of PMI after cardiac surgery. The review found that the postoperative troponin value thresholds associated with an increased risk of mortality are markedly higher than those proposed by all the current definitions of PMI. Additionally, it was found that large postoperative increases in cardiac biomarkers are prognostically relevant even in absence of additional supportive signs of ischaemia. A new algorithm for PMI detection after cardiac surgery was also proposed, and a consensus was reached within the group that establishing a prognostically relevant definition of PMI is critically needed in the cardiovascular field and that PMI should be included in the primary composite outcome of coronary intervention trials.

Thirteen Years of Impactful, Minimally Invasive Coronary Surgery: Short- and Long-Term Results for Single and Multi-Vessel Disease

OBJECTIVES

Minimally invasive coronary surgery (MICS) via lateral thoracotomy is a less invasive alternative to the traditional median full sternotomy approach for coronary surgery. This study investigates its effectiveness for short- and long-term revascularization in cases of single and multi-vessel diseases.

METHODS

A thorough examination was performed on the databases of two cardiac surgery programs, focusing on patients who underwent minimally invasive coronary bypass grafting procedures between 2010 and 2023. The study involved patients who underwent either minimally invasive direct coronary artery bypass grafting (MIDCAB) for the revascularization of left anterior descending (LAD) artery stenosis or minimally invasive multi-vessel coronary artery bypass grafting (MICSCABG). Our assessment criteria included in-hospital mortality, long-term mortality, and freedom from reoperations due to failed aortocoronary bypass grafts post-surgery. Additionally, we evaluated significant in-hospital complications as secondary endpoints.

RESULTS

A total of 315 consecutive patients were identified between 2010 and 2023 (MIDCAB 271 vs. MICSCABG 44). Conversion to median sternotomy (MS) occurred in eight patients (2.5%). The 30-day all-cause mortality was 1.3% (n = 4). Postoperative AF was the most common complication postoperatively (n = 26, 8.5%). Five patients were reoperated for bleeding (1.6%), and myocardial infarction (MI) happened in four patients (1.3%). The mean follow-up time was six years (±4 years). All-cause mortality was 10.3% (n = 30), with only five (1.7%) patients having a confirmed cardiac cause. The reoperation rate due to graft failure or the progression of aortocoronary disease was 1.4% (n = 4).

CONCLUSIONS

Despite the complexity of the MICS approach, the results of our study support the safety and effectiveness of this procedure with low rates of mortality, morbidity, and conversion for both single and multi-vessel bypass surgeries. These results underscore further the necessity to implement such programs to benefit patients.

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.).

Techniques and Technologies to Improve Vein Graft Patency in Coronary Surgery

Vein grafts are the most used conduits in coronary artery bypass grafting (CABG), even though many studies have suggested their lower patency compared to arterial alternatives. We have reviewed the techniques and technologies that have been investigated over the years with the aim of improving the quality of these conduits. We found that preoperative and postoperative optimal medical therapy and no-touch harvesting techniques have the strongest evidence for optimizing vein graft patency. On the other hand, the use of venous external support, endoscopic harvesting, vein preservation solution and anastomosis, and graft configuration need further investigation. We have also analyzed strategies to treat vein graft failure: when feasible, re-doing the CABG and native vessel primary coronary intervention (PCI) are the best options, followed by percutaneous procedures targeting the failed grafts.

Zinc-aspirin preconditioning reduces endothelial damage of arterial grafts in a rodent model of revascularization

Introduction

Coronary artery bypass grafting (CABG) is the most common cardiac surgical procedure. The prognosis of revascularization via CABG is determined by the patency of the used grafts, for which an intact endothelium is essential. The degree of ischemia-reperfusion injury (IRI), which occurs during the harvest and implantation of the grafts, is an important determinant of graft patency. Preconditioning with aspirin, a nonsteroidal anti-inflammatory drug has been shown to reduce the functional and molecular damage of arterial grafts in a rodent model. Studies have found that the zinc-aspirin complex may be able to exert an even better protective effect in pathological cardiovascular conditions. Thus, our aim was to characterize the protective effect of zinc-aspirin complex on free arterial grafts in a rodent model of revascularization.

Methods

Donor Lewis rats were treated with either zinc-aspirin, aspirin, or placebo (n = 8) for 5 days, then the aortic arches were harvested and stored in cold preservation solution and implanted heterotopically in the abdominal cavity of the recipient rats, followed by 2 h of reperfusion. There was also a non-ischemia-reperfusion control group (n = 8). Functional measurements using organ bath and histomorphological changes using immunohistochemistry were analyzed.

Results

The endothelium dependent maximal vasorelaxation was improved (non-transplanted control group: 82% ± 3%, transplanted control group: 14% ± 2%, aspirin group: 31% ± 4%, zinc-aspirin group: 52% ± 4%), the nitro-oxidative stress and cell apoptosis decreased, and significant endothelial protection was shown in the groups preconditioned with aspirin or zinc-aspirin. However, zinc-aspirin proved to be more effective in the reduction of IRI, than aspirin alone.

Discussion

Preconditioning with zinc-aspirin could be a promising way to protect the function and structural integrity of free arterial grafts, thus improving the outcomes of CABG.

The Year in Cardiothoracic and Vascular Anesthesia: Selected Highlights From 2023

This special article is the 16th in an annual series for the Journal of Cardiothoracic and Vascular Anesthesia. The authors thank the editor-in-chief, Dr. Kaplan, and the editorial board for the opportunity to continue this series, namely the research highlights of the past year in the specialty of cardiothoracic and vascular anesthesiology. The major themes selected for 2023 are outlined in this introduction, and each highlight is reviewed in detail in the main article. The literature highlights in the specialty for 2023 begin with an update on perioperative rehabilitation in cardiothoracic surgery, with a focus on novel methods to best assess patients in the preoperative and postoperative periods, and the impact of rehabilitation on outcomes. The second major theme is focused on cardiac surgery, with the authors discussing new insights into inhaled pulmonary vasodilators, coronary revascularization surgery, and discussion of causes of coronary graft failure after surgery. The third theme is focused on cardiothoracic transplantation, with discussions focusing on bridge-to-transplantation strategies. The fourth theme is focused on mechanical circulatory support, with discussions focusing on both temporary and durable support. The fifth and final theme is an update on medical cardiology, with a focus on outcomes of invasive approaches to heart disease. The themes selected for this article are only a few of the diverse advances in the specialty during 2023. These highlights will inform the reader of key updates on various topics, leading to improved perioperative outcomes for patients with cardiothoracic and vascular disease.

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.

Multi-slice CT coronary angiography versus invasive coronary angiography in the assessment of graft patency after coronary artery bypasses graft surgery

BACKGROUND

The long-term patency of arterial and venous grafts is crucial for the success of CABG. This study was designed to investigate graft patency using 128-slice coronary computed tomography angiography (CCTA) and compared the results with those obtained using invasive coronary angiography (ICA). In this observational cross-sectional study, we included 40 symptomatic post-CABG patients underwent CCTA and ICA within the same month.

RESULTS

Fifty-five percent were aged more than 60 years, and 80% were males. 67.5% had diabetes, 90% had hypertension, and 30% were smokers. Mean body mass index was 28.89 ± 5.17 kg/m2. Mean duration since CABG was 5.25 ± 4.04 years. In total, 124 native vessels and 97 grafts were assessed using CCTA and ICA. CCTA delineated 8 non-cannulated venous grafts and 6 non-cannulated left internal mammary artery grafts. CCTA required a significantly lower radiation dose (1165.77 ± 123.54 vs. 47,589.78 ± 6967.53, p < 0.001).

CONCLUSION

CCTA can be as accurate as ICA in assessing bypass grafts with less radiation dose, providing a non-invasive reliable tool for evaluation.

An elevated triglyceride-glucose index predicts adverse outcomes and interacts with the treatment strategy in patients with three-vessel disease

BACKGROUND

Insulin resistance is a pivotal risk factor for cardiovascular diseases, and the triglyceride-glucose (TyG) index is a well-established surrogate of insulin resistance. This study aimed to investigate the prognostic value of the TyG index and its ability in therapy guidance in patients with three-vessel disease (TVD).

METHODS

A total of 8862 patients with TVD with available baseline TyG index data were included in the study. The endpoint was major adverse cardiac events (MACE). All patients received coronary artery bypass grafting (CABG), percutaneous coronary intervention (PCI), or medical therapy (MT) alone reasonably.

RESULTS

An elevated TyG index was defined as the TyG index greater than 9.51. During a median follow-up of 7.5 years, an elevated TyG index was significantly associated with an increased risk of MACE (adjusted hazard ratio 1.161, 95% confidence interval 1.026-1.314, p = 0.018). The elevated TyG index was shown to have a more pronounced predictive value for MACE in patients with diabetes, but failed to predict MACE among those without diabetes, whether they presented with stable angina pectoris (SAP) or acute coronary syndrome (ACS). Meanwhile, the association between an elevated TyG index and MACE was also found in patients with left main involvement. Notably, CABG conferred a significant survival advantage over PCI in patients with a normal TyG index, but was not observed to be superior to PCI in patients with an elevated TyG index unless the patients had both ACS and diabetes. In addition, the benefit was shown to be similar between MT and revascularisation among patients with SAP and an elevated TyG index.

CONCLUSIONS

The TyG index is a potential indicator for risk stratification and therapeutic decision-making in patients with TVD.

Management of Adults With Anomalous Aortic Origin of the Coronary Arteries: State-of-the-Art Review

As a result of increasing adoption of imaging screening, the number of adult patients with a diagnosis of anomalous aortic origin of the coronary arteries (AAOCA) has grown in recent years. Existing guidelines provide a framework for management and treatment, but patients with AAOCA present with a wide range of anomalies and symptoms that make general recommendations of limited applicability. In particular, a large spectrum of interventions can be used for treatment, and there is no consensus on the optimal approach to be used. In this paper, a multidisciplinary group of clinical and interventional cardiologists and cardiac surgeons performed a systematic review and critical evaluation of the available evidence on the interventional treatment of AAOCA in adult patients. Using a structured Delphi process, the group agreed on expert recommendations that are intended to complement existing clinical practice guidelines.

Endothelial damage inhibitor preserves the integrity of venous endothelial cells from patients undergoing coronary bypass surgery

OBJECTIVES

Despite the success of coronary artery bypass graft (CABG) surgery using autologous saphenous vein grafts (SVGs), nearly 50% of patients experience vein graft disease within 10 years of surgery. One contributing factor to early vein graft disease is endothelial damage during short-term storage of SVGs in inappropriate solutions. Our aim was to evaluate the effects of a novel endothelial damage inhibitor (EDI) on SVGs from patients undergoing elective CABG surgery and on venous endothelial cells (VECs) derived from these SVGs.

METHODS

SVGs from 11 patients participating in an ongoing clinical registry (NCT02922088) were included in this study, and incubated with both full electrolyte solution (FES) or EDI for 1 h and then examined histologically. In 8 of 11 patients, VECs were isolated from untreated grafts, incubated with both FES and EDI for 2 h under hypothermic stress conditions and then analysed for activation of an inflammatory phenotype, cell damage and cytotoxicity, as well as endothelial integrity and barrier function.

RESULTS

The EDI was superior to FES in protecting the endothelium in SVGs (74 ± 8% versus 56 ± 8%, P < 0.001). Besides confirming that the EDI prevents apoptosis in SVG-derived VECs, we also showed that the EDI temporarily reduces adherens junctions in VECs while protecting focal adhesions compared to FES.

CONCLUSIONS

The EDI protects the connectivity and function of the SVG endothelium. Our data suggest that the EDI can preserve focal adhesions in VECs during short-term storage after graft harvesting. This might explain the superiority of the EDI in maintaining most of the endothelium in venous CABG surgery conduits.

Management of Adults With Anomalous Aortic Origin of the Coronary Arteries: State-of-the-Art Review

As a result of increasing adoption of imaging screening, the number of adult patients with a diagnosis of anomalous aortic origin of the coronary arteries (AAOCA) has grown in recent years. Existing guidelines provide a framework for management and treatment, but patients with AAOCA present with a wide range of anomalies and symptoms that make general recommendations of limited applicability. In particular, a large spectrum of interventions can be used for treatment, and there is no consensus on the optimal approach to be used. In this paper, a multidisciplinary group of clinical and interventional cardiologists and cardiac surgeons performed a systematic review and critical evaluation of the available evidence on the interventional treatment of AAOCA in adult patients. Using a structured Delphi process, the group agreed on expert recommendations that are intended to complement existing clinical practice guidelines.

External stenting for saphenous vein grafts in coronary artery bypass grafting: A meta-analysis

OBJECTIVES

Autologous saphenous vein grafts (SVGs) are the most commonly used bypass conduits in coronary artery bypass grafting (CABG) with multivessel coronary artery disease. Although external support devices for SVGs have shown promising outcomes, the overall efficacy and safety remains controversial. We aimed to evaluate external stenting for SVGs in CABG versus non-stented SVGs.

METHODS

MEDLINE, EMBASE, Cochrane Library and clinicaltrails.gov were searched for randomized controlled trials (RCTs) to evaluate external-stented SVGs versus non-stented SVGs in CABG up to 31 August 2022. The risk ratio and mean difference with 95% confidence interval were analysed. The primary efficacy outcomes included intimal hyperplasia area and thickness. The secondary efficacy outcomes were graft failure (≥50% stenosis) and lumen diameter uniformity.

RESULTS

We pooled 438 patients from three RCTs. The external stented SVGs group showed significant reductions in intimal hyperplasia area (MD: -0.78, p < 0.001, I2  = 0%) and thickness (MD: -0.06, p < 0.001, I2  = 0%) compared to the non-stented SVGs group. Meanwhile, external support devices improved lumen uniformity with Fitzgibbon I classification (risk ratio (RR):1.1595, p = 0.05, I2  = 0%). SVG failure rates were not increased in the external stented SVGs group during the short follow-up period (RR: 1.14, p = 0.38, I2  = 0%). Furthermore, the incidences of mortality and major cardiac and cerebrovascular events were consistent with previous reports.

CONCLUSIONS

External support devices for SVGs significantly reduced the intimal hyperplasia area and thickness, and improved the lumen uniformity, assessed with the Fitzgibbon I classification. Meanwhile, they did not increase the overall SVG failure rate.

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.

Antiplatelet Resistance in Patients Who Underwent Coronary Artery Bypass Grafting: A Systematic Review and Meta-Analysis

Antiplatelet therapy (APT) with aspirin and a P2Y12 inhibitor is commonly given to patients who underwent coronary artery bypass grafting (CABG) to reduce thrombotic events. APT resistance, the inadequate antiplatelet effect of these drugs, is a growing concern. This review aimed to assess APT resistance prevalence in patients who underwent CABG and its impact on clinical outcomes. We conducted a comprehensive search for relevant studies published to date. The included studies measured platelet function through laboratory assays and reported on clinical outcomes in patients who underwent CABG. The primary outcomes were major adverse cardiovascular events (MACEs) and mortality, whereas the secondary outcomes included acute coronary syndrome (ACS), stroke, and thromboembolic events. The meta-analysis used random-effects models, with heterogeneity assessed using the I2 statistic. The initial search identified 45 studies, with 11 meeting the inclusion criteria, involving 3,122 patients. The overall prevalence of APT resistance in patients who underwent CABG was 39%. Patients with APT resistance had significantly higher risks of MACEs and death (odds ratio [OR] 1.73, 95% confidence interval [CI] 1.06 to 2.83, p = 0.03) and postoperative myocardial infarction (OR 2.25, 95% CI 1.13 to 4.48, p = 0.02) than those without resistance. However, no significant association was found between APT resistance and stroke (OR 2.25, 95% CI 0.80 to 6.35, p = 0.12) or other thromboembolic events (OR 1.72, 95% CI 0.72 to 4.08, p = 0.22). In conclusion, APT resistance is prevalent in a significant proportion of patients who underwent CABG, increasing the risk of MACEs and postoperative myocardial infarction. These findings emphasize the need for further research to develop tailored antiplatelet strategies in this patient population.

Evaluation of the effect of simultaneous hybrid coronary revascularization on postoperative bleeding and renal function: A comparison study with minimally invasive direct off-pump coronary artery bypass grafting in patients with multivessel coronary artery disease

OBJECTIVES

The present study sought to compare postoperative bleeding and renal function in patients with multivessel coronary artery disease undergoing simultaneous hybrid coronary revascularization (HCR) and minimally invasive direct off-pump coronary artery bypass grafting (MIDCABG).

METHODS

The study retrospectively collected the data of 594 consecutive patients who underwent simultaneous HCR and 351 patients who underwent MIDCABG with planned staged HCR (MIDCABG first, then elective percutaneous coronary intervention) in Fuwai Hospital from June 2007 to December 2020. A total of 317 pairs of patients who were matched in a 1:1 ratio with propensity score matching were enrolled in this study. Bleeding and changes in renal function were compared between the 2 groups.

RESULTS

Compared with patients who underwent MIDCABG, patients who underwent simultaneous HCR had significantly greater chest tube drainage on the day of the operation (492.7 ± 282.4 mL vs 441.0 ± 261.9 mL; P = .023), but no significant difference was detected in the total amount during the postoperative period (788.8 ± 458.9 mL vs 753.3 ± 409.8 mL; P = .74). The differences in re-exploration for bleeding (0.3% vs 1.6%; P = .13), blood transfusion (18.9% vs 16.4%; P = .13), acute kidney injury (23.3% vs 18.6%; P = .53), and in-hospital major adverse cardiovascular and cerebrovascular events (including all-cause death, myocardial infarction, stroke, and repeated revascularization) (2.5% vs 1.9%; P = .67) between the 2 groups did not reach statistical significance.

CONCLUSIONS

Compared with MIDCABG, simultaneous HCR (MIDCABG first, instant percutaneous coronary intervention) did not increase postoperative bleeding or the incidence of acute kidney injury.

Effects of Fractional Flow Reserve on Coronary Artery Bypass Graft Flow to Left Anterior Descending Artery

BACKGROUND

The relationships between preoperative fractional flow reserve (FFR) values of the left anterior descending artery (LAD), FFRLAD, and intraoperative transit time flow measurement (TTFM) variables in coronary artery bypass grafting (CABG) remain unclear.Methods and Results: We retrospectively collected data for 74 in situ left internal thoracic artery (LITA) grafts and 27 saphenous vein grafts (SVGs) to the LAD that were shown to be patent on postoperative angiography. Spearman correlation coefficients were determined between FFRLADand TTFM parameters of the LITA graft, as follows: maximum flow (Qmax), -0.22 (P=0.077); minimum flow (Qmin), -0.40 (P=0.014); mean flow (Qm), -0.35 (P=0.039); pulsatility index (PI), 0.33 (P=0.008); diastolic filling (DF): 0.01 (P=0.83); and systolic reverse flow (SRF), 0.37 (P=0.002). Spearman correlation coefficients between FFRLADand TTFM parameters of the SVG to LAD were: Qmax, -0.65 (P=0.004); Qmin, -0.43 (P=0.044); Qm, -0.75 (P=0.001); PI, 0.53 (P=0.033); DF, 0.14 (P=0.48); and SRF, 0.61 (P=0.009).

CONCLUSIONS

Both LITA grafts and SVGs to the LAD show negative correlations for FFRLADwith Qminand Qm, but positive correlations for FFRLADwith PI and SFR. These relationships between FFRLADand TTFM variables of CABG grafts to the LAD should be recognized.

Graft Failure After Coronary Artery Bypass Grafting and Its Association With Patient Characteristics and Clinical Events: A Pooled Individual Patient Data Analysis of Clinical Trials With Imaging Follow-Up

BACKGROUND

Graft patency is the postulated mechanism for the benefits of coronary artery bypass grafting (CABG). However, systematic graft imaging assessment after CABG is rare, and there is a lack of contemporary data on the factors associated with graft failure and on the association between graft failure and clinical events after CABG.

METHODS

We pooled individual patient data from randomized clinical trials with systematic CABG graft imaging to assess the incidence of graft failure and its association with clinical risk factors. The primary outcome was the composite of myocardial infarction or repeat revascularization occurring after CABG and before imaging. A 2-stage meta-analytic approach was used to evaluate the association between graft failure and the primary outcome. We also assessed the association between graft failure and myocardial infarction, repeat revascularization, or all-cause death occurring after imaging.

RESULTS

Seven trials were included comprising 4413 patients (mean age, 64.4±9.1 years; 777 [17.6%] women; 3636 [82.4%] men) and 13 163 grafts (8740 saphenous vein grafts and 4423 arterial grafts). The median time to imaging was 1.02 years (interquartile range [IQR], 1.00-1.03). Graft failure occurred in 1487 (33.7%) patients and in 2190 (16.6%) grafts. Age (adjusted odds ratio [aOR], 1.08 [per 10-year increment] [95% CI, 1.01-1.15]; P=0.03), female sex (aOR, 1.27 [95% CI, 1.08-1.50]; P=0.004), and smoking (aOR, 1.20 [95% CI, 1.04-1.38]; P=0.01) were independently associated with graft failure, whereas statins were associated with a protective effect (aOR, 0.74 [95% CI, 0.63-0.88]; P<0.001). Graft failure was associated with an increased risk of myocardial infarction or repeat revascularization occurring between CABG and imaging assessment (8.0% in patients with graft failure versus 1.7% in patients without graft failure; aOR, 3.98 [95% CI, 3.54-4.47]; P<0.001). Graft failure was also associated with an increased risk of myocardial infarction or repeat revascularization occurring after imaging (7.8% versus 2.0%; aOR, 2.59 [95% CI, 1.86-3.62]; P<0.001). All-cause death after imaging occurred more frequently in patients with graft failure compared with patients without graft failure (11.0% versus 2.1%; aOR, 2.79 [95% CI, 2.01-3.89]; P<0.001).

CONCLUSIONS

In contemporary practice, graft failure remains common among patients undergoing CABG and is strongly associated with adverse cardiac events.

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.

Non-contrast computed tomography findings for identification of chronically occluded coronary artery bypass grafts

BACKGROUND

Detecting occlusions of coronary artery bypass grafts using non-contrast computed tomography (CT) series is understudied and underestimated.

PURPOSE

To evaluate morphological findings for the diagnosis of chronic coronary artery bypass graft occlusion on non-contrast CT and investigate performance statistics for potential use cases.

MATERIAL AND METHODS

Seventy-three patients with coronary artery bypass grafts who had CT angiography of the chest (non-contrast and arterial phases) were retrospectively included. Two readers applied pre-set morphologic findings to assess the patency of a bypass graft on non-contrast series. These findings included vessel shape (linear-band like), collapsed lumen and surgical graft marker without a visible vessel. Performance was tested using the simultaneously acquired arterial phase series as the ground truth.

RESULTS

The per-patient diagnostic accuracy for occlusion was 0.890 (95% confidence interval = 0.795-0.951). Venous grafts overall had an 88% accuracy. None of the left internal mammary artery to left anterior descending artery arterial graft occlusions were detected. The negative likelihood ratio for an occluded graft that is truly patent was 0.121, demonstrating a true post-test probability of 97% for identifying a patent graft as truly patent given a prevalence of 20% occlusion at a median 8.4 years post-surgery. Neither years post-surgery, nor number of vessels was associated with a significant decrease in reader accuracy.

CONCLUSION

Evaluation of coronary bypass grafts for chronic occlusion on non-contrast CT based off vessel morphology is feasible and accurate for venous grafts. Potential use cases include low-intermediate risk patients with chest pain or shortness of breath for whom non-contrast CT was ordered, or administration of iodine-based contrast is contraindicated.

Hif-1α/Slit2 Mediates Vascular Smooth Muscle Cell Phenotypic Changes in Restenosis of Bypass Grafts

Vascular smooth muscle cells (VSMCs) are involved in restenosis of bypass grafts and cause artery graft occlusion. This study aimed to explore the role of Slit2 in phenotypic switching of VSMCs and its effect on restenosis of vascular conduits. An animal model of vascular graft restenosis (VGR) was produced in SD rats and assessed by echocardiography. The expression of Slit2 and Hif-1α was measured in vivo and in vitro. After Slit2 overexpression, the migration and proliferation of VSMCs were detected in vitro, and the restenosis rates and phenotype of VSMCs were tested in vivo. The arteries of the VGR model presented significant stenosis, and Slit2 was decreased in VSMCs of the VGR model. In vitro, Slit2 overexpression inhibited the migration and proliferation of VSMCs, but Slit2 knockdown promoted migration and proliferation. Hypoxia induced Hif-1α but reduced Slit2, and Hif-1α negatively regulated Slit2 expression. Moreover, Slit2 overexpression weakened the rate of VGR and maintained the patency of artery bypass grafts, which suppressed the phenotypic switching of VSMCs. Slit2 inhibited the synthetic phenotype transformation to inhibit the migration and proliferation of VSMCs and delayed the VGR via Hif-1α.

Epsin Mimetic UPI Peptide Delivery Strategies to Improve Endothelization of Vascular Grafts

Endothelialization of engineered vascular grafts for replacement of small-diameter coronary arteries remains a critical challenge. The ability for an acellular vascular graft to promote endothelial cell (EC) recruitment in the body would be very beneficial. This study investigated epsins as a target since they are involved in internalization of vascular endothelial growth factor receptor 2. Specifically, epsin-mimetic UPI peptides are delivered locally from vascular grafts to block epsin activity and promote endothelialization. The peptide delivery from fibrin coatings allowed for controlled loading and provided a significant improvement in EC attachment, migration, and growth in vitro. The peptides have even more important impacts after grafting into rat abdominal aortae. The peptides prevented graft thrombosis and failure that is observed with a fibrin coating alone. They also modulated the in vivo remodeling. The grafts are able to remodel without the formation of a thick fibrous capsule on the adventitia with the 100 µg mL-1 peptide-loaded condition, and this condition enabled the formation of a functional EC monolayer in the graft lumen after only 1 week. Overall, this study demonstrated that the local delivery of UPI peptides is a promising strategy to improve the performance of vascular grafts.

Instantaneous wave free ratio value impact on left internal mammary artery graft patency

OBJECTIVES

To assess whether instantaneous wave - free ratio (iFR) value is associated with left internal mammary artery (LIMA) graft failure at 12 months follow-up post coronary artery bypass graft (CABG).

BACKGROUND

Data suggests bypass to a non-significant left anterior descending artery (LAD) lesion due to visual over-estimation may lead to LIMA graft failure. Implementing iFR may result in better arterial graft patency.

METHODS

In iCABG (iFR guided CABG) study patients planned to undergo an isolated CABG procedure was prospectively enrolled and iFR was performed for LAD. Coronary computed tomography angiography was performed at 2 and 12 months follow-up. The primary endpoint of this study was to determine the rate of LIMA graft occlusion or hypoperfusion at 2 and 12-months follow-up. We considered a composite secondary endpoint of Major adverse cardiovascular and cerebrovascular event (MACCE) as a secondary outcome.

RESULTS

In total 69 patients were included with no differences regarding age, sex and risk factors. At 2 months, 50 of LIMAs with pre-CABG iFR median 0.855 (0.785 - 0.892) were patent. Hypoperfusion was found in 8 LIMAs (median iFR 0.88 (0.842 - 0.90)). While, 7 LIMAs (median iFR 0.91 (0.88 - 0.96)) were occluded (p = 0.04). At 12 months, when iFR of LAD was >0.85: just 12 (31.6% out of all patent LIMAS) grafts were patent and 24 (100.0% out of all hypoperfused/occluded) grafts were hypoperfused or occluded (p < 0.001). In terms of MACCE, no difference (p = 1.0) was found between all 3 groups divided according to iFR value.

CONCLUSIONS

Instantaneous wave - free ratio value above 0.85 in LAD is a powerful tool predicting LIMA graft failure at 1-year follow up period.

Unplanned postoperative catheterization during admission for coronary artery bypass grafting is neither cheap nor benign, but may rescue patients

OBJECTIVE

Literature describing outcomes of myocardial ischemia after coronary artery bypass grafting is sparse. We hypothesized these patients had more complications and incurred higher costs of care.

METHODS

Using adult cardiac surgery data and cardiac catheterization (CathPCI) data from the Virginia Cardiac Services Quality Initiative, we identified patients who underwent unplanned cardiac catheterization after coronary artery bypass grafting from 2018 to 2021. Adult cardiac surgery data were matched to CathPCI data examining earliest in-hospital catheterization. Patients not requiring catheterization served as the control group.

RESULTS

We identified 10,597 patients who underwent isolated coronary artery bypass grafting, of whom 41 of 10,597 underwent unplanned cardiac catheterization. A total of 21 of 41 patients (51%) received percutaneous coronary intervention, most commonly for non-ST-elevation myocardial infarction (n = 7, 33%) and ST-elevation myocardial infarction (n = 6, 29%). Postoperative cardiac arrest occurred in 14 patients (40%). In patients who underwent percutaneous coronary intervention, 14 (67%) had a single lesion, 4 (19%) had 2 lesions, and 3 (14%) had 3 lesions. The left anterior descending artery (38%) was the most frequently intervened upon vessel. Patients who underwent catheterization were more likely to require balloon pump support (26% vs 11%), to have prolonged ventilation (57% vs 20%), to have renal failure (17% vs 7.1%), and to undergo reintubation (37% vs 3.8%, all P < .04). There was no statistical difference in operative mortality (4.9% vs 2.3%, P = .2) or failure to rescue (4.9% vs 1.6%, P = .14). Total costs were higher in patients who underwent unplanned catheterization ($81,293 vs $37,011, P < .001).

CONCLUSIONS

Unplanned catheterization after coronary artery bypass grafting is infrequent but associated with more complications and a higher cost of care. Therefore, determination of an association with operative mortality in patients with suspected ischemia after coronary artery bypass grafting requires additional study.

Assessment of the Graft Quality and Patency during and after Coronary Artery Bypass Grafting

Coronary artery bypass grafting (CABG) is the gold standard procedure for multi vessels and left main coronary artery disease. The prognosis and survival outcomes of CABG surgery are highly dependent on the patency of the bypass graft. Early graft failure which can occur during or soon after CABG remains a significant issue, with reported incidences of 3-10%. Graft failure can lead to refractory angina, myocardial ischemia, arrhythmias, low cardiac output, and fatal cardiac failure, emphasizing the importance of ensuring graft patency during and after surgery to prevent such complications. Technical errors during anastomosis are among the leading causes of early graft failure. To address this issue, various modalities and techniques have been developed to evaluate graft patency during and after CABG surgery. These modalities aim to assess the quality and integrity of the graft, thus enabling surgeons to identify and address any issues before they lead to significant complications. In this review article, we aim to discuss the strengths and limitations of all available techniques and modalities, with the goal to identify the best modality for evaluating graft patency during and after CABG surgery.

Antispastic Effect of Fasudil and Cocktail of Fasudil and Nitroglycerin in Internal Thoracic Artery

BACKGROUND

Spasm of arterial grafts in coronary artery bypass grafting is a clinical problem and can occasionally be lethal. Perioperative spasm in the internal thoracic artery (ITA) and coronary arteries occurs in 0.43% of patients. This study aimed to investigate the antispastic effect of a RhoA/Rho-kinase (Rho-associated coiled-coil-containing protein kinase [ROCK]) inhibitor (fasudil) with and without nitroglycerin in combination in the ITA.

METHODS

Isolated human ITA rings taken from 68 patients who were undergoing coronary bypass were studied in a myograph. Cumulative concentration-relaxation curves for fasudil (-9 to -3.5 log M) were established in the ITA, which was precontracted with potassium chloride or U46619. The inhibitory effect of fasudil (-6.3 or -5.3 log M) or fasudil in combination with nitroglycerin were also tested. The ROCK2 protein was measured by Western blot.

RESULTS

Fasudil caused similar relaxation in ITA rings contracted by potassium chloride or U46619. Pretreatment with -5.3 log M fasudil significantly depressed contraction induced by potassium chloride (P = .004 vs control; P = .017 vs -6.3 log M) and U46619 (P = .010 vs control; P = .041 vs. -6.3 log M). Fasudil in combination with nitroglycerin had more effect and more rapid and sustained relaxation than either vasodilator alone. Fasudil caused a decrease of ROCK2 protein content (P = .014).

CONCLUSIONS

Fasudil fully relaxes some vasoconstrictor-induced contraction and decreases ROCK2 protein content in the ITA. The combination of fasudil and nitroglycerin has a superior effect than either vasodilator alone. The new cocktail solution composed of fasudil and nitroglycerin (pH 7.4) has effective antispastic action and may prove to be a new antispastic method for arterial conduits during coronary bypass surgery.

Current concepts in coronary artery revascularisation

Coronary artery revascularisation can be performed surgically or percutaneously. Surgery is associated with higher procedural risk and longer recovery than percutaneous interventions, but with long-term reduction of recurrent cardiac events. For many patients with obstructive coronary artery disease in need of revascularisation, surgical or percutaneous intervention is indicated on the basis of clinical and anatomical reasons or personal preferences. Medical therapy is a crucial accompaniment to coronary revascularisation, and data suggest that, in some subsets of patients, medical therapy alone might achieve similar results to coronary revascularisation. Most revascularisation data are based on prevalently White, non-elderly, male populations in high-income countries; robust data in women, older adults, and racial and other minorities, and from low-income and middle-income countries, are urgently needed.

Operative Teaching of Coronary Bypass and Need for Repeat Catheterization: Does it Matter Who is Sewing?

OBJECTIVE

There are no studies to date comparing the patency of coronary bypass grafts constructed by attending surgeons versus trainees and the potential consequences of any such disparities. We explored this issue by comparing the patency of individual anastomoses performed by residents versus the attending surgeon.

DESIGN

We reviewed 765 continuous cases performed by a single surgeon which involved at least 1 coronary bypass anastomosis, totaling 2,173 distal anastomoses. At a median follow-up time of 36 months (interquartile range 20.5-47.3), 83 (10.9%) patients had undergone 110 cardiac catheterization procedures after their original operation for various indications. This angiographic information provided the data for our comparison cohorts.

SETTING

Cardiac surgery practice within an academic setting PARTICIPANTS: Adult patient undergoing coronary bypass grafting RESULTS: Of the 83 patients that underwent repeat catheterization, 23 (27.7%) were resident cases, 25 (30.1%) were attending cases and 35 (42.2%) were mixed. There were 4/83 (4.8%) patients with angiographic evidence of internal mammary artery graft compromise of which 3/4 (75%) had been constructed by the attending surgeon. Angiographic evidence of saphenous vein graft compromise was appreciated in 16/83 (19.3%) patients of which 9/16 (56.3%) of the grafts were constructed by the attending surgeon.

CONCLUSIONS

Liberal involvement of surgical trainees as primary operators in coronary revascularization cases led to equivalent rates of postoperative ischemic complications between the attending and resident groups. The outcome equivalence was also maintained when evaluated at the individual anastomosis patency level between the 2 groups. We conclude that academic programs should continue providing trainees significant experience as primary operating surgeons without fear of clinical outcome compromise.

Clinical outcomes and quality of life after contemporary isolated coronary bypass grafting: a prospective cohort study

OBJECTIVES

The objective of the European Multicenter Registry to Assess Outcomes in coronary artery bypass grafting (CABG) patients (DuraGraft Registry) was to determine clinical outcomes and quality of life (QoL) after contemporary CABG that included isolated CABG and combined CABG/valve procedures, using an endothelial damage inhibitor (DuraGraft) intraoperatively for conduit preservation. Here, we report outcomes in the patient cohort undergoing isolated CABG.

METHODS

The primary outcome was the composite of all-cause death, myocardial infarction (MI), or repeat revascularization (RR) [major adverse cardiac events (MACE)] at 1 year. Secondary outcomes included the composite of all-cause death, MI, RR, or stroke [major adverse cardiac and cerebrovascular events (MACCE)], and QoL. QoL was assessed with the EuroQol-5 Dimension questionnaire. Independent risk factors for MACE at 1 year were determined using Cox regression analysis.

RESULTS

A total of 2532 patients (mean age, 67.4±9.2 years; 82.5% male) underwent isolated CABG. The median EuroScore II was 1.4 [interquartile range (IQR), 0.9-2.3]. MACE and MACCE rates at 1 year were 6.6% and 7.8%, respectively. The rates of all-cause death, MI, RR, and stroke were 4.4, 2.0, 2.2, and 1.9%, respectively. The 30-day mortality rate was 2.3%. Age, extracardiac arteriopathy, left ventricular ejection fraction less than 50%, critical operative state, and left main disease were independent risk factors for MACE. QoL index values improved from 0.84 [IQR, 0.72-0.92] at baseline to 0.92 [IQR, 0.82-1.00] at 1 year ( P <0.0001).

CONCLUSION

Contemporary European patients undergoing isolated CABG have a low 1-year clinical event rate and an improved QoL.

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.

In-hospital Outcomes of Patients With and Without Previous Coronary Artery Bypass Graft Surgery Who Present With a Non-ST-Segment Elevation Myocardial Infarction

The clinical course of patients with a previous coronary artery bypass graft surgery (CABG) presenting with non-ST-elevation myocardial infarction (NSTEMI) is not well defined. We aimed to compare the management and outcomes of patients with and without previous CABG who present with an NSTEMI. Patients hospitalized with an NSTEMI between 2002 and 2018 were identified from the National Inpatient Sample. The baseline characteristics and outcomes of patients with and without a previous CABG were compared. The outcomes included the rates of invasive procedures (defined as coronary angiography, percutaneous coronary intervention [PCI], or CABG), and its individual components, and in-hospital mortality. A total of 1,445,545 cases of NSTEMI were found, of which 133,691 (9.3%) had a previous CABG. Patients with a previous CABG were older (72.4 vs 68.6 years, p <0.001), more likely men (68.8% vs 56.9%, p <0.001), and of White race (79.7% vs 74.8%, p <0.001). The previous CABG cohort had lower rates of invasive procedures (50.4% vs 65.6%, p <0.001), PCI (23.7% vs 32.0%, p <0.001), or CABG (1.2% vs 10.6%; p <0.001) in the unmatched analysis. The results were consistent in the propensity score-matched analysis with the previous CABG group less likely to receive any invasive procedures (odds ratio [OR] 0.48, 95% confidence interval [CI] 0.47 to 0.49), including coronary angiography (OR 0.54, 95% CI 0.53 to 0.55), PCI (OR 0.66, 95% CI 0.64 to 0.67), or repeat CABG (OR 0.11, 95% CI 0.10 to 0.12). Moreover, the risk of in-hospital mortality was higher in the previous CABG group (OR 1.15, 95% CI 1.10 to 1.21). In the subset of patients who were revascularized in both groups, this excess mortality was no longer observed (OR 0.82, 95% CI 0.66 to 1.03). In conclusion, a previous CABG in patients who present with NSTEMI is associated with lower rates of invasive procedures and revascularization and higher in-hospital mortality than patients without a previous CABG.

Late Clinical Outcomes of Total Arterial Revascularization or Multiple Arterial Grafting Compared to Conventional Single Arterial with Saphenous Vein Grafting for Coronary Surgery

Coronary surgery provides better long-term outcomes than percutaneous coronary intervention. Conventional practice is to use a single arterial conduit supplemented by saphenous vein grafts. The use of multiple arterial revascularization (MAG), or exclusive arterial revascularization (TAR), however, is reported as having improved late survival. Survival is a surrogate for graft failure that may lead to premature death, and improved survival reflects fewer graft failures in the non-conventional strategy groups. The reasons for not using MAG or TAR may be due to perceived technical difficulties, a lack of definitive large-scale randomized evidence, a lack of confidence in arterial conduits, or resources or time constraints. Most people consider radial artery (RA) grafting to be new, with use representing approximately 2-5% worldwide, despite select centers reporting routine use in most patients for decades with improved results. In conclusion, the current body of evidence supports more extensive use of total and multiple arterial revascularization procedures in the absence of contraindications.

Venous External Support in Coronary Artery Bypass Surgery: A Systematic Review and Meta-Analysis

OBJECTIVES

Neointimal hyperplasia and lumen irregularities are major contributors to vein graft failure and the use of VEST^(R) should prevent this. In this review, we aim to evaluate the angiographic outcomes of externally supported vein grafts.

METHODS

Medline, Embase and Cochrane Library were systematically reviewed for randomized clinical trials published by August 2022. The primary outcome was graft failure. Secondary outcomes included graft ectasia, intimal hyperplasia area and thickness, and graft non-uniformity. Odds ratios (OR) for dichotomous variables and mean difference (MD) for continuous variables with 95% confidence intervals (CI) were pooled using a fixed-effects model.

RESULTS

Three randomized controlled trials with a total of 437 patients were included with follow-up ranging from 1 to 2 years. The odds of graft failure were similar in the two groups (OR 1.22; 95%CI 0.88 to 1.71; I²=0%). Intimal hyperplasia area [MD -0.77 mm²; 95%CI -1.10 to -0.45; I²=0%] and thickness [MD -0.06 mm; 95%CI -0.08 to -0.04; I²=0%] were significantly lower in the VEST group. Fitzgibbon Patency Scale of II or III (representing angiographic conduit non-uniformity; OR 0.67; 95%CI 0.48 to 0.94; I²=0%) and graft ectasia (OR 0.53; 95%CI 0.32 to 0.88; I²=33%) were also significantly lower in the VEST group.

CONCLUSIONS

At short-term follow-up, VEST does not seem to reduce the incidence of graft failure, although it is associated with attenuation of intimal hyperplasia and non-uniformity. Longer angiographic follow-up is warranted to determine whether these positive effects might translate into a positive effect in graft failure and in long-term clinical outcomes.

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.

Long-term antithrombotic therapy after coronary artery bypass grafting in patients with preoperative atrial fibrillation. A nationwide observational study from the SWEDEHEART registry

AIMS

To provide data guiding long-term antithrombotic therapy after coronary artery by-pass grafting (CABG) in patients with preoperative atrial fibrillation (AF).

METHODS AND RESULTS

From the SWEDEHEART registry, we included all patients, between January 2006 and September 2016, with preoperative AF and CHA₂DS₂-VASC score ≥2, undergoing CABG. Based on dispensed prescriptions 12 to 18 months after CABG, patients were divided in 3 groups: use of platelet inhibitors (PI) only, oral anticoagulant (OAC) only or a combination of OAC + PI. Outcomes were: Major adverse cardiac and cerebrovascular events (MACCE, [all-cause death, myocardial infarction, or stroke]), net adverse clinical events (NACE, [MACCE or bleeding]) and the individual components of NACE. Inverse probability of treatment weighting was used to adjust for the non-randomized study design. Among 2,564 patients, 1,040 (41%) were treated with PI alone, 1,064 (41%) with OAC alone, and 460 (18%) with PI + OAC. Treatment with PI alone was associated with higher risk for MACCE (adjusted HR 1.43, 95% CI 1.09-1.88), driven by higher risk for stroke and MI, compared with OAC alone. Treatment with PI + OAC, was associated with higher risk for NACE (adjusted HR 1.40, 95% CI 1.06-1.85), driven by higher risk for bleeds, compared with OAC alone.

CONCLUSION

In this real-world observational study, a high proportion of patients with AF, undergoing CABG, did not receive a long-term OAC therapy. Treatment with OAC alone was associated with a net clinical benefit, compared with PI alone or PI + OAC.

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.

Detection of microplastics in human saphenous vein tissue using μFTIR: A pilot study

Microplastics (MPs) are ubiquitous in the environment, in the human food chain, and have been recently detected in blood and lung tissues. To undertake a pilot analysis of MP contamination in human vein tissue samples with respect to their presence (if any), levels, and characteristics of any particles identified. This study analysed digested human saphenous vein tissue samples (n = 5) using μFTIR spectroscopy (size limitation of 5 μm) to detect and characterise any MPs present. In total, 20 MP particles consisting of five MP polymer types were identified within 4 of the 5 vein tissue samples with an unadjusted average of 29.28 ± 34.88 MP/g of tissue (expressed as 14.99 ± 17.18 MP/g after background subtraction adjustments). Of the MPs detected in vein samples, five polymer types were identified, of irregular shape (90%), with alkyd resin (45%), poly (vinyl propionate/acetate, PVAc (20%) and nylon-ethylene-vinyl acetate, nylon-EVA, tie layer (20%) the most abundant. While the MP levels within tissue samples were not significantly different than those identified within procedural blanks (which represent airborne contamination at time of sampling), they were comprised of different plastic polymer types. The blanks comprised n = 13 MP particles of four MP polymer types with the most abundant being polytetrafluoroethylene (PTFE), then polypropylene (PP), polyethylene terephthalate (PET) and polyfumaronitrile:styrene (FNS), with a mean ± SD of 10.4 ± 9.21, p = 0.293. This study reports the highest level of contamination control and reports unadjusted values alongside different contamination adjustment techniques. This is the first evidence of MP contamination of human vascular tissues. These results support the phenomenon of transport of MPs within human tissues, specifically blood vessels, and this characterisation of types and levels can now inform realistic conditions for laboratory exposure experiments, with the aim of determining vascular health impacts.