Effect of different storage solutions on oxidative stress in human saphenous vein grafts

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.

Vein graft preservation with an endothelial damage inhibitor in isolated coronary artery bypass surgery: an observational propensity score-matched analysis

Background

Preservation solutions may be used intraoperatively during coronary artery bypass grafting (CABG) to flush and preserve vein grafts. The aim of this study is to evaluate the effect of DuraGraft, an endothelial damage inhibitor (EDI) preservation solution on major adverse cardiac events (MACEs) after CABG.

Methods

We conducted an observational, prospective, longitudinal, single-center study that included patients who underwent isolated CABG. The cohort treated with an EDI was matched 1:1 with a control group treated with conventional vein preservation, and matching was adjusted for possible confounding factors through propensity score (PS) matching. Three years follow-up was conducted, and the occurrence of MACE [defined as all cause-death, acute coronary syndrome (ACS), and new unplanned revascularization] was analyzed using Kaplan-Meier method.

Results

The study included 180 patients, 90 in each group. There were no significant differences in baseline characteristics across study groups. The EDI group had a significantly better event-free survival at 3 years (89% vs. 78%, log-rank test P=0.035), with an incidence rate ratio of 0.41 [95% confidence interval (CI): 0.16-0.96]. In the pre-specified subgroups analysis, the use of an EDI was associated with a significantly better event-free survival in diabetic patients (log-rank test P=0.041) and those with two or more saphenous vein grafts (log-rank test P=0.015).

Conclusions

The utilization of an EDI for vein flushing and storage after vein harvest in CABG procedures has been shown to significantly decrease the incidence of MACE at 3 years post-surgery. This protective effect is particularly notable in diabetic patients and in individuals who have multiple vein grafts.

[Transcriptome sequencing for identification of the genes associated with restenosis of venous grafts in rabbits]

OBJECTIVE

To identify the genes associated with venous graft restenosis in rabbits using transcriptome sequencing.

METHODS

Forty New Zealand rabbits were randomly divided into experimental group and control group, and in the experimental group, the left external jugular veins of the rabbits were engrafted to the left common carotid artery with continuous running suture; the rabbits in the control group received no operation. At 2 and 4 weeks after the operation, 10 rabbits from each group were euthanized and the venous grafts (in experimental group) or left external jugular vein (in control group) were harvested for measurement of the intima-media thickness using HE staining. RNA high-throughput sequencing (RNA-seq) was performed to identify the differentially expressed genes (DEGs) between the venous grafts and the control veins, and the biological functions of the DEGs were analyzed using GO and KEEG databases.

RESULTS

In the experimental group, intima-media thickening with increased extracellular matrix and vascular smooth muscle cell proliferation occurred in the venous grafts at 2 weeks and aggravated at 4 weeks after the operation. RNA high-throughput sequencing identified 1583 up-regulated genes and 608 down-regulated genes in the venous grafts in the experimental group, and GO and KEGG analysis of the DEGs pinpointed 10 hub genes, namely CD4, ZAP70, SYK, CD28, PIK3CD, CXCR4, CCR5, ITK, CCL5 and BTK.

CONCLUSION

CD4, ZAP70, SYK, CD28, PIK3CD, CXCR4, CCR5, ITK, CCL5 and BTK are probably the key genes associated with vein graft restenosis in rabbits.

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

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

The Role of Endothelial Cells in the Onset, Development and Modulation of Vein Graft Disease

Endothelial cells comprise the intimal layer of the vasculature, playing a crucial role in facilitating and regulating aspects such nutrient transport, vascular homeostasis, and inflammatory response. Given the importance of these cells in maintaining a healthy haemodynamic environment, dysfunction of the endothelium is central to a host of vascular diseases and is a key predictor of cardiovascular risk. Of note, endothelial dysfunction is believed to be a key driver for vein graft disease-a pathology in which vein grafts utilised in coronary artery bypass graft surgery develop intimal hyperplasia and accelerated atherosclerosis, resulting in poor long-term patency rates. Activation and denudation of the endothelium following surgical trauma and implantation of the graft encourage a host of immune, inflammatory, and cellular differentiation responses that risk driving the graft to failure. This review aims to provide an overview of the current working knowledge regarding the role of endothelial cells in the onset, development, and modulation of vein graft disease, as well as addressing current surgical and medical management approaches which aim to beneficially modulate endothelial function and improve patient outcomes.

Graft preservation confers myocardial protection during coronary artery bypass grafting

Background

During on-pump coronary artery bypass grafting (ONCAB), graft flushing for distal anastomoses testing also perfuses the downstream myocardium. This single-center retrospective study evaluated the impact of specific preservation solutions on myocardial protection during ONCAB.

Materials and methods

Between July 2019 and March 2020 either DuraGraft (DG) or 0.9% Saline/Biseko (SB) was applied to 272 ONCAB. Overall, 166 patients were propensity-matched into two groups. Cardiac enzymes [high-sensitive Troponin I (hs-TnI) and creatine kinase (CK)] were evaluated 7 days post-surgery.

Results

Post-surgery, hs-TnI values were significantly lower from 3 to 6 h (h) up to 4 days in the DG group: 3–6 h: 4,034 ng/L [IQR 1,853–8,654] vs. 5,532 ng/L [IQR 3,633—8,862], p = 0.05; 12–24 h: 2,420 ng/L [IQR 1,408–5,782] vs. 4,166 [IQR 2,052–8,624], p < 0.01; 2 days: 1,095 ng/L [IQR 479–2,311] vs. 1,564 ng/L [IQR 659–5,057], p = 0.02 and at 4 days: 488 ng/L [IQR 232–1,061] vs. 745 ng/L [IQR 319–1,820], p = 0.03. The maximum value: 4,151 ng/L [IQR 2,056–8,621] vs. 6,349 ng/L [IQR 4,061–12,664], p < 0.01 and the median area under the curve (AUC): 6,146 ng/L/24 h [IQR 3,121–13,248] vs. 10,735 ng/L/24 h [IQR 4,859–21,484], p = 0.02 were lower in the DG group. CK values were not significantly different between groups: maximum value 690 [IQR 417–947] vs. 631 [464–979], p = 0.61 and AUC 1,986 [1,226–2,899] vs. 2,081 [1,311–3,063], p = 0.37.

Conclusion

Repeated graft flushing with DG resulted in lower Troponin values post-surgery suggesting enhanced myocardial protection compared to SB. Additional studies are warranted to further assess the myocardial protection properties of DG.