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.

Large animal model of vein grafts intimal hyperplasia: A systematic review.

Coronary artery bypass grafting remains the treatment of choice for a large cohort of patients with significant coronary disease. Despite the increased use of arterial grafts, the long saphenous vein remains the most commonly used conduit. Long-term graft patency continues to be the Achilles heel of saphenous vein grafts. This is due to the development of intimal hyperplasia, a chronic inflammatory disease that results in the narrowing and occlusion of a significant number of vein grafts. Research models for intimal hyperplasia are essential for a better understanding of pathophysiological processes of this condition. Large animal models resemble human anatomical structures and have been used as a surrogate to study disease development and prevention over the years. In this paper, we systematically review all published studies that utilized large animal models of vein graft disease with a focus on the type of model and any therapeutic intervention, specifically the use of external stents/mesh.

Saphenous Vein Graft Failure: From Pathophysiology to Prevention and Treatment Strategies.

Saphenous vein grafts (SVGs) remain the most frequently used conduits in coronary artery bypass graft surgery (CABG). Despite advances in surgical techniques and pharmacotherapy, SVG failure rates remain high, often leading to repeat coronary revascularization. The no-touch SVG harvesting technique (minimal graft manipulation with preservation of vasa vasorum and nerves) reduces the risk of SVG failure, whereas the effect of the off-pump technique on SVG patency remains unclear. Use of buffered storage solutions, intraoperative graft flow measurement, careful selection of the target vessels, and physiological assessment of the native coronary circulation before CABG may also reduce the incidence of SVG failure. Perioperative aspirin and high-intensity statin administration are the cornerstones of secondary prevention after CABG. Dual antiplatelet therapy is recommended for off-pump CABG and in patients with a recent acute coronary syndrome. Intermediate (30%-60%) SVG stenoses often progress rapidly. Stenting of intermediate SVG stenoses failed to improve outcomes; hence, treatment focuses on strict control of coronary artery disease risk factors. Redo CABG is associated with higher perioperative mortality compared with percutaneous coronary intervention (PCI); hence, the latter is preferred for most patients requiring repeat revascularization after CABG. SVG PCI is limited by high rates of no-reflow and a high incidence of restenosis during follow-up. Drug-eluting and bare metal stents provide similar long-term outcomes in SVG PCI. Embolic protection devices reduce no-reflow and should be used when feasible. PCI of the corresponding native coronary artery is associated with better short- and long-term outcomes and is preferred over SVG PCI, if technically feasible.

Drug-Eluting versus Bare-Metal Stents in Saphenous Vein Grafts Compared to Native Coronary Vessels: The Norwegian Coronary Stent Trial Study.

BACKGROUND: Drug-eluting stents (DES) reduce target lesion revascularization (TLR) with no effect on mortality or myocardial infarction (MI) compared to bare-metal stents (BMS) in native vessels. Randomized stent studies in saphenous vein grafts (SVG) are few and the reported effects are ambiguous. The Norwegian Coronary Stent Trial study is the first to randomize lesions to percutaneous coronary intervention in native vessels and SVG. AIMS: The aim of this study was to compare the rate of mortality, MI, and TLR across stent and vessel types. METHODS: In this substudy, 6,087 patients with a single lesion in native vessels and 164 in SVG were followed for 5 years. RESULTS: MI was more frequent in SVG (subdistributional hazard ratio [SHR] 4.95 (3.75-6.54, p < 0.001), but not affected by stent type. In the first 500 days, DES reduced TLR in native vessels (SHR 0.21 (0.15-0.30) p < 0.001) and SVG (SHR 0.18 (0.04-0.80) p = 0.02). Thereafter, DES and BMS were equivalent in native vessels, but DES had a higher TLR rate than BMS in SVG (SHR 3.31 (1.23-8.94) p = 0.02). After 5 years, the TLR rate was still significantly lower for DES in native vessels (3.2% vs. 7.8%, p < 0.001) but not in SVG (21.4% vs. 18. 4%). CONCLUSION: In SVG, no difference in TLR between DES and BMS was observed after 5 years in contrast to persistent benefit in native vessels. The high rate of TLR and MI in SVG makes treatment of native vessels a preference whenever feasible and better treatment options for SVG are warranted.

All-Trans Retinoic Acid Prevented Vein Grafts Stenosis by Inhibiting Rb-E2F Mediated Cell Cycle Progression and KLF5-RARα Interaction in Human Vein Smooth Muscle Cells.

PURPOSE: Vein graft failure (VGF) is an important limitation for coronary artery bypass graft (CABG) surgery. Inhibition of the excessive proliferation and migration of venous smooth muscle cells (SMCs) is an effective strategy to alleviate VGF during the CABG perioperative period. In the present study, we aimed to explore the role and potential mechanism of all-trans retinoic acid (ATRA) on preventing vein grafts stenosis. METHODS: The autogenous vein grafts model was established in the right jugular artery of rabbits. Immunohistochemistry staining and western blot assays were used to detected the protein expression, while real-time PCR assay was applied for mRNAs expression detection. The interaction between proteins was identified by co-immunoprecipitation assay. The Cell Counting Kit-8 and wound-healing assays were used to investigate the role of ATRA on human umbilical vein smooth muscle cells (HUVSMCs) function. Cell cycle progression was identified by flow cytometry assay. RESULTS: Vein graft stenosis and SMCs hyperproliferation were confirmed in vein grafts by histological and Ki-67 immunohistochemistry assays. Treatment of ATRA (10 mg/kg/day) significantly mitigated the stenosis extent of vein grafts, demonstrated by the decreased thickness of intima-media, and decreased Ki-67 expression. ATRA could repress the PDGF-bb-induced excessive proliferation and migration of HUVSMCs, which was mediated by Rb-E2F dependent cell cycle inhibition. Meanwhile, ATRA could reduce the interaction between KLF5 and RARα, thereby inhibiting the function of cis-elements of KLF5. KLF5-induced inducible nitric oxide synthase (iNOS) expression activation could be significantly inhibited by ATRA. CONCLUSIONS: These results suggested that ATRA treatment may represent an effective prevention and therapy avenue for VGF.

Coronary Artery Bypass Graft Patency and Survival in Patients on Dialysis.

BACKGROUND: Little is known about graft patency after coronary artery bypass grafting (CABG) performed in patients on dialysis. Our aim was to assess patency of internal thoracic artery (ITA) grafts and saphenous vein grafts (SVGs) in these patients. METHODS: From 1/1997 to 1/2018, 500 patients on dialysis underwent primary CABG with or without concomitant procedures at Cleveland Clinic, 40 of whom had 48 postoperative angiograms for recurrent ischemic symptoms. Complete follow-up was obtained on all but 1 patient lost to follow-up 1 y after CABG. Thirty-six ITA grafts and 65 SVGs were evaluable for stenosis and occlusion. RESULTS: Two of 40 patients (5%) had emergency CABG; 3 (7.5%) with calcified aortas had a change in operative strategy to avoid ascending aortic manipulation, 2 (5%) had poor conduit quality, and 12 (30%) had severe diffuse atherosclerotic disease with calcification of the coronary targets causing technical difficulties. Thirty-three patients (82%) were bypassed with an in situ ITA and 3 (7.5%) had a free ITA graft. Three of 36 ITA grafts were occluded at 0.78, 1.8, and 9.4 y (too few to model). SVG patency was 52% and 37% at 1 and 2 y, respectively. CONCLUSIONS: Among patients on dialysis who underwent CABG, coronary angiography for ischemic symptoms in a select subset revealed that SVG patency was lower than expected from published reports in the general CABG population and may contribute to the poor prognosis of this cohort. Further work is needed to guide graft selection and improve graft patency in dialysis patients.

[Comparison of graft vessel versus native vessel strategies for late saphenous vein graft disease after coronary artery bypass grafting].

Objective: To compare clinical efficacy of interventional treatment with graft vessel and native coronary artery for patients with late saphenous vein grafts disease(SVGD) after coronary artery bypass grafting (CABG). Methods: A total of 1 608 patients underwent CABG in Tianjin Chest from March 2014 to December 2017 were screened. During the follow-up period, 165 hospitalized patients with recurrence of angina pectoris within one year after CABG, who had at least one narrow vein graft(≥50%) confirmed by the coronary angiography were enrolled. According to the results of angiography and surgeon's clinical experiences, the patients received interventional treatment to vein grafts(grafts group, n=53) or native coronary vessels(native group, n=112). The operation success rate, mortality and incidence of serious complications after interventional treatment in two groups at the time of hospitalization were compared.And the incidence of major adverse cardiovascular events(MACE) in two groups at one year after discharge were also compared. Kaplan-Meier survival curve was used to compare the cumulative event-free survival rates. The risk factors for the MACE in the patients with late SVGD and treated by interventional therapy were analyzed by Cox regression analysis. Results: A total of 165 patients were included for analysis, including 98 males(59.4%). The age was (64.2±7.1) years old. The follow-up time was 12 (8, 12) months. In the grafts group, operation success rate was 90.57%(48/53), and 3 cases(5.66%) suffered from serious complications after interventional treatment, 2 cases(3.77%) died. For native group the operation success rate was 88.39%(99/112), and 7(6.25%) cases suffered from serious complications after interventional treatment, and no deaths. The operation success rate and the incidences of serious complications after interventional treatment in two groups had no statistically significant difference(both P>0.05). The mortality in hospital of native group was lower than that in grafts group(P<0.05). Within 12 months after discharge, there was no statistically significant difference in incidence of MACE of two groups (11.32%(6/53) vs. 10.71%(12/112), P>0.05). Survival analysis showed that the cumulative event-free survival rates in two groups were 73.58% (39/53) and 66.13%(74/112), and there was no statistically significant difference (P>0.05). Cox regression analysis showed acute coronary syndrome (HR=41.203, 95%CI 4.859-349.361, P<0.01), and peripheral vascular diseases (HR=2.808, 95%CI 1.067-7.393, P<0.05) were the risk factors of the MACE for the patients treated by interventional therapy with late SVGD. Conclusion: For the patients with late SVGD after CABG, the success rate of intervention with vein grafts and own coronary vessels are both high with satisfactory safety.The in-hospital mortality of interventional therapy in own coronary vessels is lower than in graft vessel. Patients with acute coronary syndrome and peripheral vascular disease have a poor prognosis.

Renal Autotransplantation with Autologous Saphenous Vein Graft in a Patient with Takayasu Arteritis and Existing Renal Artery Stent in Her Solitary Kidney.

Takayasu arteritis is a disease that results in the granulomatous inflammation of large vessel walls. Takayasu arteritis is generally observed in young females during the second or third decades of life. This disease is treated by the revascularization of the affected organs either by surgery or by endovascular interventions. In this study, we present a case where renal autotransplantation was performed on a lady with an autologous saphenous vein graft subsequent to numerous previous endovascular interventions for her solitary kidney due to Takayasu arteritis-induced renal artery stenosis. The patient was prevented from becoming dialysis dependent through this surgical intervention. Renal autotransplantation is the choice of treatment, especially for those in whom endovascular interventions have failed. Patient management must include the partnership of an experienced vascular surgeon, transplant urologist, rheumatologist, nephrologist and radiologist.

Comparison between the STENTYS self-apposing bare metal and paclitaxel-eluting coronary stents for the treatment of saphenous vein grafts (ADEPT trial).

AIMS: To describe the safety and performance of STENTYS self-expandable bare metal stents (BMS) versus paclitaxel-eluting stents (PES) in saphenous vein grafts (SVGs). METHODS AND RESULTS: A randomised controlled trial was performed in four hospitals in three European countries between December 2011 and December 2013. Patients with de novo lesions (>50% stenosis) in an SVG with a diameter between 2.5-6 mm were included. Primary endpoint was late lumen loss at 6 months. Secondary endpoints included procedural success and the occurrence of major adverse cardiac events (MACE) at 12 months. A total of 57 patients were randomised to STENTYS self-apposing BMS (n = 27) or PES (n = 30). Procedural success was obtained in 89.5%. No significant differences in late lumen loss were found between BMS and PES at 6 months (0.53 mm vs 0.47; p = 0.86). MACE rates at 12 months were comparable in both groups (BMS 22.2% vs. PES 26.7%; p = 0.70). CONCLUSIONS: Treatment of SVGs with STENTYS self-expandable stents is safe and effective. No significant differences were found in late lumen loss and MACE between BMS and PES.

[The Role of Bone Morphogenic Protein-4 in the Progression of Vein Graft Hyperplastic Remodeling under Hyperglycemic Condition].

OBJECTIVE: This study was designed to assess the vessel wall characteristics and the expression levels of bone morphogenic protein4(BMP4) and proliferating cell antigen Ki67 in vein grafts harvested from diabetic rats,and to investigate the role of BMP4 in progression of vein graft hyperplastic remodeling under hyperglycemic condition. METHODS: 48 male SpragueDawky rats [body mass (194±16) g] aged 8 weeks were randomly divided into diabetes mellitus (DM) group ( n=24) and nondiabetes mellitus (NDM) group ( n=24). The DM rats were induced by streptozotocin in combination with highsugar and highfat diet. The unilateral external jugular vein was interposition grafted into the common carotid arteries in the two groups. The vein grafts were harvested at preoperatively and 1,2 and 4 weeks postoperatively ( n=6) in each group. The morphological characteristics of the venous graft wall were evaluated by hematoxylineosin staining,and the expression levels and the distribution of Ki67 and BMP4 were assessed by immunohistochemistry analysis,then the expression of BMP4 gene and protein was measured by realtime polymerase chain reaction (RTPCR) and Western blot assay respectively. RESULTS: In the progression of rats vein grafts hyperplastic remodeling,the venous wall thickness of rats thickened with time increasing,and the intimal and medial thickness of the vein grafts harvested from DM rats were significantly higher than those from NDM rats at the same time postoperatively ( P<0.05). Ki-67 was highly xpressed in smooth muscle cells nucleus located in the rats vein grafts,and its expression level was up-regulated gradually in the progression of vein graft failure,and the Ki 67 positive cells of vein grafts from DM rats were significantly higher than those from NDM controls at the same period ( P<0.05). Immunohistochemistry analysis showed that BMP4 was expressed in smooth muscle cells cytoplasmof the rats vein grafts,combined with the results of RT-PCR and Western blot assay,there was a little BMP4 expression could be seen in venous wall of NDM rats,while BMP4 positive cells and the expression level of BMP4 gene and protein from DM rats vein grafts was increasing with obvious time dependence and significantly higher than the NDM rats ( P<0.05). CONCLUSION: The morphological and pathological changes within the venous wall were significantly correlated with the high expression levels of BMP4 in vein grafts harvested from diabetic rats,implying a potential role of BMP4 in the progression of accelerated vein graft failure under hyperglycemic condition.

Safety and clinical effectiveness of drug-eluting stents for saphenous vein graft intervention in older individuals: Results from the medicare-linked National Cardiovascular Data Registry(®) CathPCI Registry(®) (2005-2009).

OBJECTIVES: To evaluate the safety of drug-eluting stents (DES) when treating patients with failing saphenous vein grafts (SVG). BACKGROUND: DES reduce target vessel revascularization in patients with failing SVGs; however, compared with bare metal stents (BMS), DES have been variably associated with increased mortality. METHODS: Clinical records from National Cardiovascular Data Registry(®) CathPCI Registry(®) (49,325 older individuals [≥65 years] who underwent SVG stenting 2005-2009) were linked to Medicare claims to create a longitudinal record. Death, myocardial infarction (MI), and urgent revascularization with DES versus BMS were evaluated to 3 years using propensity matching (PM). Results were stratified by clinical presentation (acute coronary syndrome [ACS], non-ACS), previous lesion treatment (in-stent, de novo), and graft segment (aortic, body, distal anastomosis). RESULTS: In this older cohort (median age, 75 years), acute presentations were prevalent (ACS, 69%; TIMI flow <3, 45%), and adverse clinical outcomes were common by 3 years (death, 24.5%; MI, 14.6%; urgent revascularization, 29.5%). Among DES patients (n = 31,403), 3-year mortality was lower (vs. BMS) (22.7% vs. 28.0%, P < 0.001; PM hazard ratio [HR] 0.87, 95% confidence interval 0.83-0.91), and no difference was observed in the adjusted risk for MI (PM HR 0.97, 0.91 to 1.03) or urgent revascularization (PM HR 1.04, 0.99-1.08). These findings were independent of clinical presentation, previous lesion treatment, and graft segment (P interaction, ns). CONCLUSIONS: In this large SVG PCI cohort, all-cause mortality was lower among those receiving DES, and no difference in MI or urgent revascularization was observed to 3 years. © 2015 Wiley Periodicals, Inc.

Extracellular Vesicles Derived from Adipose Mesenchymal Stem Cells Regulate the Phenotype of Smooth Muscle Cells to Limit Intimal Hyperplasia.

PURPOSE: Extracellular vesicles (EVs) derived from mesenchymal stem cells (MSCs) play important roles in the reduction of inflammation in multiple disease models. However, their role in vein graft (VG) remodeling is undefined. We aimed to investigate the effect of EVs from adipose MSCs (ADMSC-EVs) on VG intimal hyperplasia and to explore the possible mechanisms. METHODS: After generation and characterization of control-EVs and ADMSC-EVs in vitro, we investigated their effect on the proliferation and migration of vascular smooth muscle cells (VSMCs) in vitro. Next, we established a mouse model of VG transplantation. Mice underwent surgery and received control-EVs or ADMSC-EVs by intraperitoneal injection every other day for 20 days. VG remodeling was evaluated after 4 weeks. We also assessed the effect of ADMSC-EVs on macrophage migration and inflammatory cytokine expression. RESULTS: Significant inhibitory effects of ADMSC-EVs on in vitro VSMC proliferation (p < 0.05) and migration (p < 0.05) were observed compared with control-EVs. The extent of intimal hyperplasia was significantly decreased in ADMSC-EV-treated mice compared with control-EV-treated mice (26 ± 8.4 vs. 45 ± 9.0 µm, p < 0.05). A reduced presence of macrophages was observed in ADMSC-EV-treated mice (p < 0.05). Significantly decreased expression of inflammatory cytokines interleukin (IL)-6 and monocyte chemoattractant protein-1 (MCP-1) was also found in the ADMSC-EV-treated group (both p < 0.05). In addition, phosphorylation of Akt, Erk1/2, and p38 in VGs was decreased in the ADMSC-EV-treated group. CONCLUSIONS: We demonstrated that ADMSC-EVs exert an inhibitory effect on VG neointima formation by regulating VSMC proliferation and migration, macrophage migration, inflammatory cytokine expression, and the related signaling pathways.

Stenting as a bail-out option after failed percutaneous transluminal angioplasty in infrainguinal vein bypass grafts.

OBJECTIVES: To study the safety and efficacy of bare and covered stents in infrainguinal vein grafts after failure of PTA for treating graft stenoses. METHODS: An analysis of a prospective database of all patients who underwent stenting of infrainguinal vein bypass grafts at this institution between 1 January 2008 and 31 December 2012 was carried out. The main outcome considered was primary patency, which was reported at 1, 6 and 12 months. RESULTS: A total of 18 patients with a mean age of 73 years (range: 56 to 86) were included. The indications for stent placement were significant recoil (7, 39%), graft rupture (6, 33%), residual vein cusps (3, 17%) and aneurysmal degeneration (2, 11%). There was a high overall technical success rate of 94% (17/18) and arrest of haemorrhage was achieved in all cases of graft rupture. The primary patency at 1, 6 and 12 months was 89%, 71% and 59%, respectively. CONCLUSION: The use of bare and covered stents in infrainguinal vein grafts appears safe and effective. They are an excellent bail-out option for the treatment of graft rupture and give acceptable short-term results.

[The Association Between Bone Morphogenic Protein-4 and in-situ Saphenous Vein Graft Pathology in Diabetic Patients Undergoing Coronary Revascularization].

OBJECTIVES: This study was designed to assess the expression levels of bone morphogenic protein-4 (BMP4) in saphenous veins harvested from diabetic patients undergoing coronary artery bypass grafting (CABG), and to investigate its association with in-situ morphological and pathological changes within the venous wall. METHODS: From January 2013 to December 2014, forty patients with type 2 diabetes mellitus (DM) and risk factors matched non-DM controls (n =40) were enrolled prospectively. Of the 40 DM patients, 24 had noninsulin-dependent diabetes (NIDM) and the remaining 16 had insulin-dependent diabetes (IDM). Segments of saphenous vein without surgical dilatation from these 80 patients were obtained. Vessel wall characteristics were evaluated by hematoxylin-eosin (HE) staining, and the expression and distribution of BMP4 was assessed by Western blot assay and immunohistochemistry analysis. RESULTS: The intimal and medial thickness of the saphenous veins harvested from DM patients were higher than those from non-DM controls. Compared with non-DM patients, the expression level of BMP4 was significantly elevated in diabetic veins ( P<0.05), and BMP4 was highly expressed in smooth muscle cells located in the medial layer. Moreover, the expression levels of BMP4 in diabetic veins were significantly correlated with intimal thickness (r =0.655, P<0.01), intimal area (r =0.684, P<0.01), medial thickness (r =0.642, P<0.01) and medial area (r =0.692, P<0.01). CONCLUSIONS: The pre-existing intimal and medial hyperplasia were significantly correlated with the high expression levels of BMP4 in saphenous veins harvested from diabetic patients, implying a potential role of BMP4 in the progression of vein graft stenotic diseases in this cohort of post-CABG patients. Future studies were warranted in investigating novel therapeutic strategy targeting at BMP4 for improving long-term vein graft patency.

Retrieval of a subintimal fractured guide wire from the brachial artery following saphenous vein graft stenting.

We present a case of a 58-year-old woman with diabetes mellitus with a history of angina, coronary artery bypass 24 years previously and who underwent retrieval of a fractured coronary buddy wire from the right brachial artery following attempted coronary intervention to a saphenous vein graft via the right radial route. Attempted removal of the guide wire had caused guide catheter-induced dissection of the vein graft in addition to a distal stent edge dissection before fracture in the brachial artery. The fractured end of the buddy wire was found to be in the subintimal space and could only be retrieved by advancing the wire into the subclavian artery by means of wrapping its free portion around the guiding catheter. Its fractured end could then be snared into the guiding catheter but could only be withdrawn from behind the stented segment in the vein graft by means of a trap balloon in the guiding catheter. Successful stenting of a guide catheter-induced dissection and distal stent edge dissection within the vein graft was then performed. This case highlights the hazards of deploying stents over buddy wires and of fractured guide wires in coronary intervention. © 2015 Wiley Periodicals, Inc.

Utility of arteriovenous loops before free tissue transfer for post-traumatic leg defects.

Crush injuries of severe magnitude involving lower limbs require complex bone and soft tissue reconstructions in the form of microvascular free tissue transfers. However, satisfactory recipient vessels are often unavailable in the leg due to their vulnerability to trauma and post traumatic vessel disease (PTVD), which extends well beyond the site of original injury. In such situations, healthy recipient vessels for free flap anastomosis can be made available by constructing temporary arteriovenous loops with saphenous vein grafts, anastomosed to corresponding free flap vessels. Our study included 7 patients with severe crush injuries of leg due to rail and road traffic accidents. Long and short saphenous vein grafts were anastomosed to Femoral artery in the subsartorial canal in 2 cases and to large muscular branches and accompanying veins in rest of the cases. Free flap transfers were performed in the same sitting in 6 cases. One case showed insufficient dilatation of the vein loop and hence free flap transfer was staged. Free Latissimus dorsi, Gracilis and Rectus abdominis flaps were performed. There were two cases of flap necrosis - one in the case of a pathologic vein graft with staged flap transfer which showed vein thrombosis on re exploration. The other case of flap failure was caused by a hematoma underneath the flap. In another patient, secondary haemorrhage occurred on day 18, without any consequence to the flap. All the other cases had complete free flap survival. We consider the use of single stage arteriovenous loops, a valuable tool to increase the applications of free flap, whenever healthy recipient vessels are not available in the periphery of the trauma.

Outcomes of Head and Neck Free Tissue Transfer Requiring Vein Grafting: Systematic Review and Meta-analysis.

OBJECTIVE: To systematically review the literature to determine the prevalence of free flap failure in head and neck free flaps requiring vein grafting. DATA SOURCES: Search strategies created in collaboration with a medical librarian were implemented using PubMed, Cochrane, Scopus, Web of Science, and Google Scholar from inception to August 2022. REVIEW METHODS: The population of interest included adult and pediatric patients undergoing reconstruction of oncologic or traumatic head and neck defects with a free flap requiring a vein graft that presents the success/failure rate. The primary outcome was the flap failure rate, and the secondary outcome was the flap compromise/revision rate. Inclusion and exclusion criteria were designed to capture all study designs. Initially, 2778 articles were identified by the search strategy. Two reviewers independently performed the review, data extraction for analysis, and a quality assessment. Primary Reporting Items for Systematic Reviews and Meta-analyses guidelines were followed. Meta-analysis was performed using a random effects model. RESULTS: Eleven studies of 789 flaps were included for data extraction. Random effects meta-analysis resulted in an estimated prevalence of free flap failure of 12.30% (95% confidence interval: 6.39%-19.49%, I2 = 77.4%). CONCLUSION: Taking into account that head and neck free tissue transfers that require a vein graft are typically associated with more challenging reconstructions and the lack of a suitable alternative, vein grafts appear to be a reliable method for bridging the gap between the flap and recipient vessels in head and neck free tissue transfer when indicated.

External stenting for saphenous vein grafts reduces early postoperative graft failure.

OBJECTIVES: Multiple studies have shown that external stenting (ExSt) mitigates the progression of vein graft disease years after coronary artery bypass grafting (CABG). We used computed tomography to evaluate the effect of ExSt on perioperative vein graft patency. METHODS: This study assessed graft patency rates of saphenous vein grafts (SVG) in consecutive patients with isolated coronary artery bypass grafting (CABG) between 2018 and 2021. Logistic regression analyses were conducted to compare the outcomes of supported and non-supported groups at both patient and graft levels, with age, EuroSCORE II, gender, diabetes and arterial grafts as covariates. Subgroup analyses were performed based on different covariates. The goal of the study was to provide valuable insights into the clinical outcomes of SVG in patients having CABG. RESULTS: The study examined a total of 357 patients who met the inclusion criteria and evaluated 572 vein grafts. Of these, 150 patients (205 SVGs) received ExSt, whereas 207 patients (337 SVGs) did not receive ExSt. The study results indicated that the likelihood of overall SVG patency at discharge was higher in the stented group than in the non-stented group, both at the level of the grafts [93.8% vs 87.8%, odds ratio (OR) 2.1; 95% confidence interval (CI) 1.0-4.5; P = 0.05] and at the patient level (90.1% vs 83.5%, OR 1.8; 95% CI 0.9-3.6; P = 0.1). It is worth noting that the difference between the stented and non-stented groups was most significant in the subgroup that received 2 arterial grafts (96.5% vs 89.6%, OR 3.2; 95% CI 1.2-8.4; P = 0.02) and in the subgroup with a higher EuroSCORE II (median >1.1) (98.6% vs 88.6%, OR 8.8; 95% CI 1.1-72.7; P = 0.04). CONCLUSIONS: The ExSt is associated with improved perioperative SVG patency at both the graft and the patient levels. Moreover, SVGs to the right territory and high-risk patients appear to have an advantage using ExSt.

Impact of distension pressure on saphenous vein endothelial injury in coronary artery bypass grafting.

Introduction: Long saphenous vein grafts (LSVGs) are pivotal conduits in coronary artery bypass grafting (CABG), yet concerns persist regarding early failure and long-term patency. Endothelial damage, a potent initiator of graft failure, necessitates exploration of factors contributing to endothelial injury during LSVG preparation. Methods: A prospective, single-center study was conducted, assessing the impact of unregulated distension pressure on LSVG endothelium during CABG. Histological and CD31 (cluster of differentiation 31) immunohistochemical analyses were performed on 21 paired vein samples, categorized into non-distended (group A) and distended (group B) groups. Pressure recordings were obtained using different syringe sizes during vein distension. Results: Histological examination revealed a significantly higher percentage of endothelial cell loss in distended veins (31.95% ± 31.31) compared to non-distended veins (11.67% ± 28.65) (p = 0.034). CD31 immunohistochemistry corroborated greater endothelial cell loss in distended veins (p = 0.001). The pressure recordings with a 20-cc syringe, as opposed to using a 10-cc syringe, were considerably lower (44.5 mmHg vs. 92.75 mmHg) emphasizing the inverse relationship between syringe size and pressure generated. In our study, pre-existing endothelial injury was observed in one-third of diabetic patients (36%), with all instances of such injury exclusively identified in individuals with diabetes. Conclusion: Unregulated distension pressure during LSVG preparation is associated with greater endothelial damage, as evidenced by histological and immunohistochemical analyses. The inverse relationship between syringe size and pressure underscores the importance of controlled distension.