Impact of the size mismatch between saphenous vein graft and coronary artery on graft patency

Optimal Conduit Diameter Selection in Coronary Bypass Grafting Using Saphenous Vein

BACKGROUND

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

METHODS

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

RESULTS

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

CONCLUSIONS

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

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.

Anomalous Right Coronary Artery Originating From the Pulmonary Artery (ARCAPA): A Rare Presentation in the Fifth Decade

Presented is a case report of a 54-year-old male Jehovah's Witness diagnosed with an anomalous right coronary artery originating from the main pulmonary artery with the initial presentation with a history of episodic fatigue, chest pain, palpitation, and bodily weakness. The patient was managed with reimplantation of the anomalous coronary artery onto the ascending aorta.

Sex differences in saphenous vein graft patency: A systematic review and meta-analysis

BACKGROUND

Saphenous vein grafts (SVG) are the most commonly used conduits in coronary artery bypass grafting (CABG). Graft failure is observed in up to 50% of SVG at 10 years after surgery. Whether a difference in SVG patency rates exists between men and women remains unclear.

METHODS

We performed a study-level meta-analysis to evaluate sex-related differences in follow-up patency rates of SVG after CABG. A systematic literature search was conducted to identify studies on CABG that reported follow-up SVG patency rates in men and women. The primary outcome was SVG patency rates by sex at follow-up.

RESULTS

Seventeen studies totaling 8235 patients and 14,781 SVG grafts were included. There was no significant difference in follow-up SVG patency rates between men and women (incidence rate ratio 0.96, 95% confidence interval 0.90-1.03, p = .24), with mean angiographic follow-up of 33.5 months (standard deviation 29.2). Leave-one-out and cumulative analysis were consistent with the main analysis. We concluded that follow-up SVG patency rate is similar between men and women undergoing CABG.

Impact of the no-touch harvesting technique on the vessel diameter of saphenous vein grafts for coronary artery bypass grafting

Objectives

To explore the impact of the no-touch harvesting technique on the vessel diameter of saphenous vein grafts.

Methods

This retrospective, single-center study enrolled 166 patients who underwent isolated coronary artery bypass grafting using saphenous vein grafts. Saphenous vein grafts were harvested conventionally in 83 patients (conventional group) and using the no-touch technique in 83 patients (no-touch group). We analyzed graft patency and the vessel diameters of saphenous vein grafts in the pre- and postoperative states. The diameter mismatch between the saphenous vein grafts and the coronary artery at the anastomotic site was also measured; preoperative diameter was measured using ultrasound imaging, and the postoperative diameter was measured using electrocardiogram-gated enhanced computed tomography.

Results

A total of 135 saphenous vein grafts (66 and 69 grafts in the conventional and no-touch groups, respectively) were evaluated for postoperative patency. Graft patency was equivalent in the 2 groups (conventional, 96.9% vs no-touch, 100%; P = .24). A detailed evaluation was performed in 109 saphenous vein grafts (52 and 57 grafts in the conventional and no-touch groups, respectively). Saphenous vein graft diameter was significantly distended in the conventional group (preoperative, 2.6 ± 0.7 mm vs postoperative, 3.4 ± 0.5 mm; P < .0001). However, saphenous vein graft diameter did not change in the no-touch group (preoperative, 2.9 ± 0.4 mm vs postoperative 2.8 ± 0.4 mm, P = .33). The diameter mismatch was significantly smaller in the no-touch group (conventional 1.4 ± 0.6 mm vs no-touch 1.0 ± 0.4 mm, P < .0001).

Conclusions

The no-touch technique avoids the expansion of graft diameter and diameter mismatch between the saphenous vein grafts and coronary artery.

Linking the region-specific tissue microstructure to the biaxial mechanical properties of the porcine left anterior descending artery

Coronary atherosclerosis is the main cause of death worldwide. Advancing the understanding of coronary microstructure-based mechanics is fundamental for the development of therapeutic tools and surgical procedures. Although the passive biaxial properties of the coronary arteries have been extensively explored, their regional differences and the relationship between tissue microstructure and mechanics have not been fully characterized. In this study, we characterized the passive biaxial mechanical properties and microstructural properties of the proximal, medial, and distal regions of the porcine left anterior descending artery (LADA). We also attempted to relate the biaxial stress-stretch response of the LADA and its respective birefringent responses to the polarized light for obtaining information about the load-dependent microstructural variations. We found that the LADA extensibility is reduced in the proximal-to-distal direction and that the medial region exhibits more heterogeneous mechanical behavior than the other two regions. We have also observed highly dynamic microstructural behavior where fiber families realign themselves depending on loading. In addition, we found that the microstructure of the distal region exhibited highly aligned fibers along the longitudinal axis of the artery. To verify this microstructural feature, we imaged the LADA specimens with multi-photon microscopy and observed that the adventitia microstructure transitioned from a random fiber network in the proximal region to highly aligned fibers in the distal region. Our findings could offer new perspectives for understanding coronary mechanics and aid in the development of tissue-engineered vascular grafts, which are currently limited due to their mismatch with native tissue in terms of mechanical properties and microstructural features. STATEMENT OF SIGNIFICANCE: The tissue biomechanics of coronary arteries is fundamental for the development of revascularization techniques such as coronary artery bypass. These therapeutics require a deep understanding of arterial mechanics, microstructure, and mechanobiology to prevent graft failure and reoperation. The present study characterizes the unique regional mechanical and microstructural properties of the porcine left anterior descending artery using biaxial testing, polarized-light imaging, and confocal microscopy. This comprehensive characterization provides an improved understanding of the collagen/elastin architecture in response to mechanical loads using a region-specific approach. The unique tissue properties obtained from this study will provide guidance for the selection of anastomotic sites in coronary artery bypass grafting and for the design of tissue-engineered vascular grafts.

Intraoperative angiography during coronary artery bypass grafting

INTRODUCTION

The aim of this study was to evaluate the incidence rate of technical failure of graft patency while performing intra-operative angiography after coronary artery bypass grafting.

METHODS

This prospective pilot study included 50 patients with multi-vessel coronary artery disease who underwent coronary artery bypass grafting, in addition to intra-operative angiographic graft assessments, on open-chest. Overall, 144 grafts and 160 distal anastomoses were assessed in a hybrid operating room.

RESULTS

Intra-operative angiography allowed the identification of 23 angiographic defects (15.9% of all grafts) in 22 patients (44%): three graft defects (2% of all grafts), 17 anastomotic defects (10.6% of all distal anastomoses), and three target artery errors (1.8% of all grafted arteries). Ten re-interventions (43.4%) were performed based on the angiographic defects detected. During the follow-up period, computed tomography angiography of the attached grafts at a mean of 224 days (range, 80-318 days) showed that all repaired grafts were patent. During surgery, the total mean dose of radiation was 1.848 ± 0.54 mSv (range, 0.78-3.4 mSv) per patient and investigation time was 19.4 ± 4.94 minute (range, 9-31 minute).

CONCLUSIONS

Intra-operative angiography is a powerful tool allowing the identification of graft defects, anastomotic defects and target vessel errors. Assuming relatively low level of exposure to radiation and short investigation time, intra-operative angiography could be included in routine practice as safe procedure improving surgery quality.

Development of a risk score for early saphenous vein graft failure: An individual patient data meta-analysis

OBJECTIVES

Early saphenous vein graft (SVG) occlusion is typically attributed to technical factors. We aimed at exploring clinical, anatomical, and operative factors associated with the risk of early SVG occlusion (within 12 months postsurgery).

METHODS

Published literature in MEDLINE was searched for studies reporting the incidence of early SVG occlusion. Individual patient data (IPD) on early SVG occlusion were used from the SAFINOUS-CABG Consortium. A derivation (n = 1492 patients) and validation (n = 372 patients) cohort were used for model training (with 10-fold cross-validation) and external validation respectively.

RESULTS

In aggregate data meta-analysis (48 studies, 41,530 SVGs) the pooled estimate for early SVG occlusion was 11%. The developed IPD model for early SVG occlusion, which included clinical, anatomical, and operative characteristics (age, sex, dyslipidemia, diabetes mellitus, smoking, serum creatinine, endoscopic vein harvesting, use of complex grafts, grafted target vessel, and number of SVGs), had good performance in the derivation (c-index = 0.744; 95% confidence interval [CI], 0.701-0.774) and validation cohort (c-index = 0.734; 95% CI, 0.659-0.809). Based on this model. we constructed a simplified 12-variable risk score system (SAFINOUS score) with good performance for early SVG occlusion (c-index = 0.700, 95% CI, 0.684-0.716).

CONCLUSIONS

From a large international IPD collaboration, we developed a novel risk score to assess the individualized risk for early SVG occlusion. The SAFINOUS risk score could be used to identify patients that are more likely to benefit from aggressive treatment strategies.

The clinical application of microincision vein harvesting of the great saphenous vein in coronary artery bypass grafting

BACKGROUND

The present study aimed to summarize the clinical application of microincision vein harvesting (MVH) of the great saphenous vein in coronary artery bypass grafting (CABG).

METHODS

From July 2014 to October 2017, 160 patients underwent coronary artery bypass grafting. Among them, 80 patients received MVH of the great saphenous vein, and 80 received open venous harvesting (OVH). The results of the sampling operation, complications during hospitalization, and the long-term patency of the great saphenous vein were compared between the two groups.

RESULTS

All the patients in both groups received successful operations. The difference in the length of the veins obtained and the injury of the veins was not statistically significant (P > 0.05). The difference in the long-term patency rate of the graft vessels between the two groups was not statistically significant. The in-hospital mortality rate was the same in both groups. The MVH group had noticeable advantages over the OVH group in terms of the vein collection times, the incision length, and the complications experienced when performing the leg incisions (P < 0.01). The time relating to the patients' observed early out-of-bed activity was significantly longer in the MVH group. Furthermore, the patients' hospitalization length was significantly shorter in the MVH group compared to the OVH group (P < 0.05). The MVH group had significant advantages in pain score and patient satisfaction, and this difference was also statistically significant (P < 0.05).

CONCLUSIONS

The MVH procedure met the requirements of CABG in vein grafting. When compared with OVH, MVH can significantly reduce leg incision complications and improve patients' overall satisfaction with their hospital experience.

No-touch saphenous vein graft harvesting technique for coronary artery bypass grafting

OBJECTIVES

Although the patency of internal artery grafts in coronary artery bypass grafting (CABG) is superior to that of saphenous vein grafts (SVGs), good long-term patency rates have been reported with SVGs harvested using the no-touch technique. Here, we report the early results of CABG with no-touch SVGs (NT-SVGs) along with the precautions required while handling these grafts.

METHODS

This retrospective study included 41 patients who underwent CABG with NT-SVGs between May 2016 and March 2018. NT-SVGs were harvested with minimal electric scalpel use, and post-harvesting vascular overdilation with a syringe was not performed. Blood with heparinized saline was used to prevent vascular endothelial damage. A drain was inserted into the SVG harvest site, which was closed with a single interrupted suture, and elasticated bandage and compression stockings were used to prevent fluid retention and avoid delayed wound healing.

RESULTS

There was no case of postoperative thoracotomy due to bleeding or myocardial infarction, and postoperative graft assessment confirmed graft patency in all patients, with a little mismatch between the diameters of SVG and the anastomotic vessel. Delayed wound healing at the graft harvest site seemed to improve after introducing the above procedures.

CONCLUSIONS

Early results of CABG with NT-SVGs were good. Some precautions must be taken during harvesting and anastomosis. Taking precautions described in this study may help reduce the risk of perioperative complications and make the no-touch technique the standard procedure for harvesting SVGs for CABG.

Review of risk factors, treatment, and prevention of saphenous vein graft disease after coronary artery bypass grafting

Saphenous vein graft disease (SVGD) is a type of vascular disease that may develop after coronary artery bypass grafting (CABG). SVGD seriously affects the short-term and long-term effects of CABG and increases the incidence of major adverse cardiovascular events. It is very important to identify patients at greatest risk and carry out prevention and treatment measures to determine the risk factors for SVGD. Many factors contribute to SVGD when the vein is grafted into an arterial environment, such as surgery-related factors, smoking, diabetes mellitus, hyperlipidemia, and others. In this review, we discuss the risk factors for SVGD, current surgical and pharmacologic therapies with which to manage SVGD, and the prevention of SVGD.