Coronary Artery Bypass: Review of Surgical Techniques and Impact on Long-Term Revascularization Outcomes

CTA in roadmapping post-CABG evaluation

Although coronary artery bypass grafting (CABG) outcomes are typically highly successful, outpatient evaluation of bypass grafts is an important step. Moreover, the return of myocardial ischemia and acute coronary syndrome (ACS) events after bypass is not uncommon. Whether due to failure of prior bypass grafts or progression of underlying arteriosclerosis in native coronaries, regularly evaluating if a patient requires intervention (and assessing graft patency vs. closure) is essential. Imaging via cardiac computed tomography angiography (CTA) offers a gold standard anatomical map to facilitate efficiency and accuracy in later invasive coronary angiography (ICA) or surgical re-CABG intervention. This review discusses the utility of CTA as a safe pre and post CABG evaluation tool, in guiding outpatient evaluation of graft patency and roadmapping subsequent reintervention if needed. We seek to ameliorate clinical uncertainties and synthesize growing amounts of research, to help encourage a homogenous approach to post-CABG evaluation. This comprehensive review paper introduces the indications for bypass grafting surgery and transcatheter PCI approaches, details techniques and strategies for bypass surgery, discusses CTA in evaluating post-CABG graft patency, and consolidates research surrounding pre-reintervention CTA in post-CABG patients. Last, this review explores future directions in standardizing post-CABG evaluation guidelines.

Comparison of the effects of perioperative fentanyl and morphine use on the short-term prognosis of patients with cardiac surgery in the ICU

Aim

This study aimed to analyze the effects of perioperative morphine and fentanyl use on delirium, length of ICU stay, and in-hospital mortality after cardiac surgery.

Methods

This cohort study retrieved the data of 4,596 patients admitted to ICU after cardiac surgery in MIMIC-IV database from 2008 to 2019. The primary outcome was postoperative delirium. The secondary outcomes were length of ICU stay, and in-hospital mortality. To compare the effects of perioperative fentanyl and morphine use on postoperative delirium, length of ICU stay, and in-hospital mortality, univariate, two-way stepwise, as well as multivariable Logistic regression, linear regression, and Cox proportional hazards models was respectively used. Odd ratio (OR), β coefficient, hazard ratio (HR), and respective confidence interval (CI) were calculated. Subgroup analysis was conducted in terms of age, use of extracorporeal circulation, midazolam, dexmedetomidine or surgery type.

Results

In total, the data of 4,596 patients were analyzed including 2,589 morphine user and 2007 fentanyl user. We found that the risk of postoperative delirium was reduced in patients with cardiac surgery undergoing perioperative morphine relative to perioperative fentanyl (OR = 0.62, 95%CI: 0.40-0.96). Perioperative morphine use was negatively correlated with the length of ICU stay in patients with cardiac surgery in comparison to patients with perioperative fentanyl use (β = -0.72, 95%CI: -1.06, -0.39). Relative to patients who had perioperative fentanyl, patients who had perioperative morphine were associated with reduced risk of in-hospital mortality in patients with cardiac surgery after adjusting for respective confounding factors (HR = 0.35, 95%CI: 0.13-0.91).

Conclusion

Perioperative morphine use was related to lower risk of delirium and in-hospital mortality as well as shortened length of ICU stay in these patients. The findings might offer a reference for perioperative anesthesia management in patients receiving cardiac surgery.

Introducing sequential partial aortic clamp technique for proximal anastomoses and its advantages in myocardial protection in coronary artery bypass grafting

Ischemic heart disease (IHD) is a common and potentially lethal cardiovascular disorder. Coronary artery bypass grafting (CABG) is a standard procedure for treating IHD. This study aims to introduce a novel technique for proximal anastomoses in CABG. This clinical trial studied 29 cases and 29 matched controls. Data were gathered from June 2014 to June 2023. Regarding proximal anastomoses, the sequential partial aortic clamp was performed in cases, and the partial aortic clamp was done for controls. In the sequential partial aortic clamp technique, a relatively small or medium vascular clamp was used instead of one clamp for all proximal anastomoses, which closed a small amount of the aortic wall at each stage. At each stage, only one hole in the aortic wall and only one anastomosis between the conduit and the aorta was performed. After the end of each anastomosis, the clamp was opened and placed on another part of the aorta, and the next anastomosis was performed. CK-MB (p < 0.001, Eta Squared = 0.255) level was significantly lower in cases that underwent sequential partial ascending aorta clamping. However, cTnI level was not statistically different among cases and controls(p = 0.05). Of all patients, 3 (10.3%) cases and 12 (41.4%) controls developed with postoperative atrial fibrillation (p = 0.007). The sequential partial aortic clamp technique leads to less myocardial injury than the partial aortic clamp technique. Also, patients undergoing sequential partial aortic clamp technique are less likely to develop postoperative atrial fibrillation.

3D Printing for Cardiovascular Surgery and Intervention: A Review Article

3D printing technology can be applied to practically every aspect of modern life, fulfilling the needs of people from various backgrounds. The utilization of 3D printing in the context of adult heart disease can be succinctly categorized into 3 primary domains: preoperative strategizing or simulation, medical instruction, and clinical consultations. 3D-printed model utilization improves surgical planning and intraoperative decision-making and minimizes surgical risks, and it has demonstrated its efficacy as an innovative educational tool for aspiring surgeons with limited practical exposure. Despite all the applications of 3D printing, it has not yet been shown to improve long-term outcomes, including safety. There are no data on the outcomes of controlled trials available. To appropriately diagnose heart disease, 3D-printed models of the heart can provide a better understanding of the intracardiac anatomy and provide all the information needed for operative planning. Experientially, 3D printing provides a wide range of perceptions for understanding lower extremity arteries' spatial geometry and anatomical features of pathology. Practicing cardiac surgery processes using objects printed using 3D imaging data can become the norm rather than the exception, leading to improved accuracy and quality of treatment. This study aimed to review the various applications of 3D printing technology in cardiac surgery and intervention.

Aortic Regurgitation After Right Coronary Cusp Injury During Percutaneous Coronary Intervention

Injury of a coronary cusp of the aortic valve is a rare complication that can occur during coronary angiography. It usually occurs from multiple attempts with different catheters to access the ostia of the right coronary artery, but it has also occurred accessing the ostia of the left coronary artery. We present the case of a patient who underwent coronary angiography with suspected coronary cusp injury that remained asymptomatic but was found to have severe aortic regurgitation during coronary artery bypass graft surgery (CABG) one week later, requiring an aortic valve replacement.

Integrated biophysical matching of bacterial nanocellulose coronary artery bypass grafts towards bioinspired artery typical functions

Revascularization via coronary artery bypass grafting (CABG) to treat cardiovascular disease is established as one of the most important lifesaving surgical techniques worldwide. But the shortage in functionally self-adaptive autologous arteries leads to circumstances where the clinical reality must deal with fighting pathologies coming from the mismatching biophysical functionality of more available venous grafts. Synthetic biomaterial-based CABG grafts did not make it to the market yet, what is mostly due to technical hurdles in matching biophysical properties to the complex demands of the CABG niche. But bacterial Nanocellulose (BNC) Hydrogels derived by growing biofilms hold a naturally integrative character in function-giving properties by its freedom in designing form and intrinsic fiber architecture. In this study we use this integral to combine impacts on the luminal fiber matrix, biomechanical properties and the reciprocal stimulation of microtopography and induced flow patterns, to investigate biomimetic and artificial designs on their bio-functional effects. Therefore, we produced tubular BNC-hydrogels at distinctive designs, characterized the structural and biomechanical properties and subjected them to in vitro endothelial colonization in bioreactor assisted perfusion cultivation. Results showed clearly improved functional properties and gave an indication of successfully realized stimulation by artery-typical helical flow patterns.

Recent Advances in Coronary Artery Bypass Grafting Techniques and Outcomes: A Narrative Review

Coronary artery bypass grafting (CABG) has witnessed remarkable progress in recent years, driven by innovative techniques and refined approaches that have transformed patient outcomes and treatment paradigms. This review article comprehensively explores the latest advances in CABG techniques and their consequential impacts on patient outcomes. The advent of minimally invasive CABG techniques has revolutionized traditional surgical approaches. Robotic-assisted surgery and small thoracotomy methods offer reduced invasiveness, yielding shorter recovery times and improved patient satisfaction. Integrating CABG with percutaneous coronary intervention (PCI), hybrid procedures have emerged as a versatile strategy, providing tailored treatment solutions for complex coronary anatomies. The paradigm shift to off-pump CABG, which preserves the beating heart during surgery, has shown promise in reducing perioperative complications and neurocognitive deficits. Advances in graft selection, particularly the utilization of arterial grafts such as the internal thoracic artery and radial artery, have significantly enhanced graft patency rates and long-term survival. Adjunctive technologies, such as intraoperative imaging and graft flow assessment, have bolstered the precision of CABG procedures. Pharmacological agents have demonstrated their potential to improve graft outcomes. Surgical decision-making is now optimized based on patient characteristics and disease severity owing to the development of patient selection and risk stratification tools. Long-term results have also significantly improved. Patients undergoing CABG have higher survival rates, less angina, and better quality of life. Developing more resilient grafts through tissue engineering, using bioresorbable materials in graft fabrication, and using gene therapy to improve graft patency and overall cardiac recovery are all exciting future research directions. This review's summary of current developments in CABG procedures highlights their profoundly positive effects on patient outcomes. These developments can change the face of cardiovascular care by giving clinicians more tools to treat coronary artery disease (CAD) and enhance patients' quality of life.

Preoperative albumin corrected anion gap is associated with in-hospital and long-term mortality in patients undergoing coronary artery bypass grafting in a retrospective cohort study

Background

Coronary artery disease remains a global health concern and the leading cause of death. Till today, coronary artery bypass grafting (CABG) is one of the main treatment strategies for coronary artery disease, especially for Multivessel coronary disease or complex coronary lesions. The present study aimed to explore the relationship of preoperative albumin corrected anion gap (ACAG) with mortality in all those patients who undergoing CABG.

Methods

All the patients undergoing CABG were included in the study. All clinical data were collected from CareVue and MetaVision system. The predictive value of ACAG for mortality was determined by receiver operating characteristic (ROC) curves survival curves were estimated using the Kaplan-Meier method. Multivariate regression models were constructed to determine the association of ACAG with mortality.

Results

A total of 2,180 patients were identified and divided into a high ACAG group (ACAG ≥16.0 mmol/L) and low ACAG group (ACAG <16.0 mmol/L) according to the ROC analysis. Patients in the high ACAG group were older and presented with more comorbidities and concomitant valvular surgeries. Further more, in the high ACAG group, we observed a higher length of stay in the intensive care unit [3.88 (2.15, 7.09) vs. 2.29 (1.29, 3.94), P<0.001]. Both the in-hospital mortality [28 (4.5%) vs. 11 (0.7%), P<0.001], and the 4-year mortality [125 (27.1%) vs. 111 (12.7%), P<0.001] were also rised in those patients. And it was also showed in the survival curves, patients with ACAG ≥16.0 mmol/L had a significant lower 4-year survival (P<0.001). While in the multivariate regression model, we found ACAG was act as an independent risk factor for both the in-hospital mortality [odds ratio (OR): 1.248 (1.060, 1.470), P=0.008] and the 4-year mortality [hazard ratio (HR): 1.134 (1.063, 1.210), P<0.001]. An ACAG ≥16.0 mmol/L was significantly associated with a 2.7-fold risk of in-hospital mortality [OR: 2.732 (1.129, 6.610), P=0.026].

Conclusions

Preoperative ACAG is an independent risk factor for in-hospital and long-term mortality in CABG patients. A higher ACAG may relate to severe coronary artery stenosis and cardiac dysfunction, which is more likely to lead to a postoperative systemic inflammatory response, microcirculation disorder, and subsequent complications.

Microfluidic bioprinting of tough hydrogel-based vascular conduits for functional blood vessels

Three-dimensional (3D) bioprinting of vascular tissues that are mechanically and functionally comparable to their native counterparts is an unmet challenge. Here, we developed a tough double-network hydrogel (bio)ink for microfluidic (bio)printing of mono- and dual-layered hollow conduits to recreate vein- and artery-like tissues, respectively. The tough hydrogel consisted of energy-dissipative ionically cross-linked alginate and elastic enzyme-cross-linked gelatin. The 3D bioprinted venous and arterial conduits exhibited key functionalities of respective vessels including relevant mechanical properties, perfusability, barrier performance, expressions of specific markers, and susceptibility to severe acute respiratory syndrome coronavirus 2 pseudo-viral infection. Notably, the arterial conduits revealed physiological vasoconstriction and vasodilatation responses. We further explored the feasibility of these conduits for vascular anastomosis. Together, our study presents biofabrication of mechanically and functionally relevant vascular conduits, showcasing their potentials as vascular models for disease studies in vitro and as grafts for vascular surgeries in vivo, possibly serving broad biomedical applications in the future.

Diagnostic and Management Strategies in Patients with Late Recurrent Angina after Coronary Artery Bypass Grafting

PURPOSE OF REVIEW

This review will outline the current evidence on the anatomical, functional, and physiological tools that may be applied in the evaluation of patients with late recurrent angina after coronary artery bypass grafting (CABG). Furthermore, we discuss management strategies and propose an algorithm to guide decision-making for this complex patient population.

RECENT FINDINGS

Patients with prior CABG often present with late recurrent angina as a result of bypass graft failure and progression of native coronary artery disease (CAD). These patients are generally older, have a higher prevalence of comorbidities, and more complex atherosclerotic lesion morphology compared to CABG-naïve patients. In addition, guideline recommendations are based on studies in which post-CABG patients have been largely excluded. Several invasive and non-invasive diagnostic tools are currently available to assess graft patency, the hemodynamic significance of native CAD progression, left ventricular function, and myocardial viability. Such tools, in particular the latest generation coronary computed tomography angiography, are part of a systematic diagnostic work-up to guide optimal repeat revascularization strategy in patients presenting with late recurrent angina after CABG.

Mechano-regulated cell-cell signaling in the context of cardiovascular tissue engineering

Cardiovascular tissue engineering (CVTE) aims to create living tissues, with the ability to grow and remodel, as replacements for diseased blood vessels and heart valves. Despite promising results, the (long-term) functionality of these engineered tissues still needs improvement to reach broad clinical application. The functionality of native tissues is ensured by their specific mechanical properties directly arising from tissue organization. We therefore hypothesize that establishing a native-like tissue organization is vital to overcome the limitations of current CVTE approaches. To achieve this aim, a better understanding of the growth and remodeling (G&R) mechanisms of cardiovascular tissues is necessary. Cells are the main mediators of tissue G&R, and their behavior is strongly influenced by both mechanical stimuli and cell-cell signaling. An increasing number of signaling pathways has also been identified as mechanosensitive. As such, they may have a key underlying role in regulating the G&R of tissues in response to mechanical stimuli. A more detailed understanding of mechano-regulated cell-cell signaling may thus be crucial to advance CVTE, as it could inspire new methods to control tissue G&R and improve the organization and functionality of engineered tissues, thereby accelerating clinical translation. In this review, we discuss the organization and biomechanics of native cardiovascular tissues; recent CVTE studies emphasizing the obtained engineered tissue organization; and the interplay between mechanical stimuli, cell behavior, and cell-cell signaling. In addition, we review past contributions of computational models in understanding and predicting mechano-regulated tissue G&R and cell-cell signaling to highlight their potential role in future CVTE strategies.

Infrared Thermographic Imaging of Chest Wall Perfusion in Patients Undergoing Coronary Artery Bypass Grafting

Coronary artery disease represents a leading cause of death worldwide, to which the coronary artery bypass graft (CABG) is the main method of treatment in advanced multiple vessel disease. The use of the internal mammary artery (IMA) as a graft insures an improved long-term survival, but impairment of chest wall perfusion often leads to surgical site infection and increased morbidity and mortality. Infrared thermography (IRT) has established itself in the past decades as a non-invasive diagnostic technique. The applications vary from veterinary to human medicine and from head to toe. In this study we used IRT in 42 patients receiving CABG to determine the changes in skin surface temperature preoperatively, two hours, 24 h and 6 days after surgery. The results showed a significant and independent drop of surface temperature 2 h after surgery on the whole surface of the chest wall, as well as a further reduction on the left side after harvesting the IMA. The temperature returned to normal after 24 h and remained so after 6 days. The study has shown that IRT is sufficiently sensitive to demonstrate the known, subtle reduction in chest wall perfusion associated with IMA harvesting.

Bioengineering silk into blood vessels

The rising incidence of cardiovascular disease has increased the demand for small diameter (<6 mm) synthetic vascular grafts for use in bypass surgery. Clinically available synthetic grafts (polyethylene terephthalate and expanded polytetrafluorethylene) are incredibly strong, but also highly hydrophobic and inelastic, leading to high rates of failure when used for small diameter bypass. The poor clinical outcomes of commercial synthetic grafts in this setting have driven significant research in search of new materials that retain favourable mechanical properties but offer improved biocompatibility. Over the last several decades, silk fibroin derived from Bombyx mori silkworms has emerged as a promising biomaterial for use in vascular applications. Progress has been driven by advances in silk manufacturing practices which have allowed unprecedented control over silk strength, architecture, and the ensuing biological response. Silk can now be manufactured to mimic the mechanical properties of native arteries, rapidly recover the native endothelial cell layer lining vessels, and direct positive vascular remodelling through the regulation of local inflammatory responses. This review summarises the advances in silk purification, processing and functionalisation which have allowed the production of robust vascular grafts with promise for future clinical application.