Current role of saphenous vein graft in coronary artery bypass grafting

Advanced Manufacturing of Coil-Reinforced Multilayer Vascular Grafts to Optimize Biomechanical Performance

Small diameter vascular grafts require a complex balance of biomechanical properties to achieve target burst pressure, arterial compliance-matching, and kink resistance to prevent failure. Iterative design of our multilayer vascular was previously used to achieve high compliance while retaining the requisite burst pressure and suture retention strength for clinical use. To impart kink resistance, a custom 3D solution printer was used to add a polymeric coil to the electrospun polyurethane graft to support the graft during bending. The addition of this reinforcing coil increased kink resistance but reduced compliance. A matrix of grafts were fabricated and tested to establish key structure-property relationships between coil parameters (spacing, diameter, modulus) and biomechanical properties (compliance, kink radius). A successful graft design was identified with a compliance similar to saphenous vein grafts (4.1 ± 0.4 %/mmHgx10-2) while maintaining comparable kink resistance to grafts used currently in the clinic. To explore graft combinations that could increase graft compliance to match arterial values while retaining this kink resistance, we utilized finite element (FE) models of compliance and kink radius that simulated experimental testing. The FE-predicted graft compliance agreed well with experimental values. Although the kink model over-predicted the experimental kink radius values, key trends between graft parameters and kink resistance were reproduced. As an initial proof-of-concept, the validated models were then utilized to parse through a targeted graft design space. Although this initial parameter range tested did not yield a graft that improved upon the previous balance of graft properties, this combination of advanced manufacturing and computational framework paves the way for future model-driven design to further optimize graft performance.

Unsung Heroes of Coronary Interventions: Indian Cardiac Surgeons and the Challenges of South Asian Coronary Anatomy and Physiology

Background and significance: The coronary artery disease (CAD) epidemic has seen a logarithmic increase in morbidity and mortality over the past decade. Cardiovascular diseases account for about 19.1 million deaths annually—with 80% of reports coming from low and middle-income countries, which have been attributed to a lack of infrastructure, human resources, and financial coverage. In tandem with the developed world, India has also seen significant growth in interventional and surgical cardiovascular care. The dominance of coronary artery bypass grafting (CABG) procedures in India has attracted the attention of the world. With this review, the authors aim to highlight the role of cardiac surgeons in India as the “unsung heroes” of coronary interventions. Observations: A pernicious atherosclerotic pathology develops in thendian population as a result of genetic and socio-cultural predispositions, which is further complicated by anatomical and physiological differences. The pathology manifests as a diffuse disease in relatively small caliber coronary arteries, necessitating the consideration of CABG over interventional procedures. Indian cardiac surgeons have stood up to the challenge and have powered health tourism to India from around the world due to the excellent success rate and long-term outcomes at a 50–80% lesser cost than most developed countries. Beyond the costs, a major highlight is the high rate of arterial bypass and off-pump surgery. These balance the unbridled exuberance of the interventional cardiology medical–industrial complex, providing a critical balance that benefits patients and improves acute and long-term outcomes. Conclusions: Indian cardiac surgery is now known globally not only for its affordability but also for the skill set and the quality of surgeons. The surgeons’ vast experience and risk-taking capacity have made them an indispensable part of the interventional cardiology team and has allowed a multidisciplinary collaboration that inspires the world. This is evident from the rising trend of medical tourism to India.

Long-Term Outcomes of Vein Adjuncts in Distal Infrainguinal Bypass

BACKGROUND

Autologous vein is recommended for infrainguinal bypass due to improved freedom from occlusion compared to prosthetic graft. In patients without adequate vein, a vein adjunct at the distal anastomosis has been suggested to improve patency in small studies. This study aimed to determine if performance of a distal vein adjunct was associated with improved freedom from occlusion in below-knee popliteal and tibial bypasses compared to prosthetic bypass alone.

METHODS

A retrospective review of the Vascular Quality Initiative Infrainguinal Bypass database was conducted. Patients undergoing prosthetic-only and prosthetic with vein adjuncts were compared. Inclusion criteria included age ≥18 years, and bypass to below-knee popliteal or tibial vessels. Exclusion criteria included autologous vein conduits and prior interventions. Groups were further divided into below-knee popliteal and tibial subgroups.

RESULTS

A cohort of 3,939 patients underwent bypass to the below-knee popliteal artery, with 287 (7.3%) receiving vein adjuncts. More patients were male (68.8 vs. 57.8%, P < 0.001) and had higher rates of congestive heart failure (21.1 vs. 16.0%, P = 0.040) within the below-knee popliteal group. Two-year bypass occlusion was decreased in patients receiving vein adjuncts (11.6 vs. 17.1%, P = 0.004). A cohort of 2,378 patients underwent tibial bypass, with 473 (19.9%) receiving vein adjuncts. Within the tibial group, patients were similar in age, body mass index, race, comorbidities, and indications. Bypass occlusion (24.8 vs. 17.6%, P = 0.005) and amputation (20.5 vs. 15.9%, P = 0.048) rates at 2 years were worse for patients who did not receive a distal vein adjunct to tibial arteries.

CONCLUSIONS

Distal vein adjuncts are associated with improved freedom from occlusion, amputation, major adverse limb events, and overall survival when compared to bypasses performed with prosthetic graft alone for tibial bypasses within the Vascular Quality Initiative. A vein adjunct was not associated with improved freedom from occlusion in below-knee popliteal bypasses. Consideration should be given to utilization of a distal vein adjunct to improve prosthetic bypass longevity and limb salvage for patients requiring tibial bypasses.

The Current Status of Minimally Invasive Conduit Harvesting for Coronary Artery Bypass Grafting

The harvesting of conduits for coronary artery bypass surgery has evolved over the last decade to include endoscopic approaches to access the saphenous vein, radial artery, and internal mammary artery. These minimally invasive techniques reduce the morbidity associated with open procedures by decreasing pain and recovery time and increasing mobility post operatively. This review highlights the differences in morbidity, quality, and patency between the most common conduits that are harvested minimally invasively for coronary artery bypass grafting surgery.

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.

External Stenting for Saphenous Vein Grafts in Coronary Surgery: A Systematic Review and Meta-Analysis

The external stenting of saphenous vein grafts (SVGs) during coronary artery bypass grafting (CABG) has been proven to reduce intimal hyperplasia (IH) in animal models, paving the way for human randomized controlled trials (RCTs) to be conducted. Herein, we performed a study-level meta-analysis to assess the impact of the Venous External SupporT (VEST) device, an external stent, on the outcomes of SVGs. A systematic search was conducted to identify all RCTs comparing VEST-stented to non-stented SVGs in patients undergoing CABG. The primary outcome was graft occlusion. The main secondary outcomes were repeat revascularization, SVG IH area, and intimal-medial thickness. Two RCTs totaling 407 patients were included. At a mean follow-up of 1.5 years, there was no difference in graft occlusion between groups (incidence rate ratio: 1.11; 95% confidence interval (CI): 0.80-1.53). The rate of repeat revascularization was also similar (odds ratio: 0.66; 95% CI: 0.27-1.64). The IH area (standardized mean difference (SMD): -0.45; 95% CI: -0.79 to -0.10) and intimal-medial thickness (SMD: -0.50; 95% CI: -0.90 to -0.10) were significantly reduced in the VEST group. Our findings show that significant reductions in the IH area and the intimal-medial thickness in VEST-stented SVGs do not currently translate into a lesser need for repeat revascularization or less graft occlusion events compared to non-stented SVGs at 1.5 years after CABG.

Current practice of saphenous vein graft harvesting in coronary artery bypass graft surgery: an Indian survey

Purpose

The treatment of occluded saphenous vein graft (SVG) is challenging, and thus preventing the graft occlusion is of utmost importance. However, despite its recognized importance, a paucity of data exists regarding how SVGs are handled and preserved. Hence, this survey was conducted to document the techniques of vein graft preservation and handling among cardiac surgeons in India.

Methods

The survey had 26 questions regarding vein graft usage, harvesting, handling, and preservation techniques. Three hundred cardiac surgeons across India participated in this survey between March 2019 and July 2019.

Results

Responses were received from 215 (71.6%) surgeons across 13 states. Around 87% of respondents reported that ≥ 76% of veins were harvested by the open technique. Among the respondents, around 67% used one SVG in ≥ 96% of their patients, 45% used two SVGs in ≥ 86% of their patients, and 38% used ≥ 3 SVGs in < 25% of their patients, respectively. Around 54%, 27%, 9%, and 9% of respondents used autologous whole blood, saline solution, pH-buffered solution, and other solutions, respectively. In addition, 96.74% of respondents heparinized their vein graft preservation solutions, and 98.14% preserved the solution at room temperature. 34.88% and 83.26% of respondents used dual antiplatelet therapy (DAPT) before and after surgery in ≥ 76% of their patients, respectively. 63.26% of the surgeons reported that the patients received DAPT for > 12 months.

Conclusion

There is a significant variance in the process of vein harvesting, preservation, handling, and antiplatelet therapy protocols among various cardiac surgeons across India. Therefore, there is a need for standardization in the practice of vein harvesting.

Coronary artery disease imaging reporting and data system (CAD-RADS): what radiologists need to know?

The aim of this work is to review Coronary Artery Disease Imaging Reporting and Data System (CAD-RADS) that was designed to standardize reporting language and improve the communication of data among radiologists and clinicians. Stenotic lesions are graded into 5 grades ranging from 0 (no stenosis) to 5 (total occlusion), where the highest grade represents the final score. The expert consensus platform has added 4 special modifiers (non-diagnostic, stent, graft, and vulnerability) to aid patient management through linking these scores with decision algorithm and treatment plan. Adherence to standard imaging protocol; knowledge of normal, variant, and anomalous anatomy; and skillful evaluation of stenosis are important for proper utilization of this reporting system. Lastly, radiologists should be aware of the inherited benefits, limitations, and common pitfalls of this classification system.