Vasa Vasorum in Saphenous Vein for CABG: A Review of Morphological Characteristics

This short article discusses selected scanning electron microscope and transmission electron microscope features of vasa vasorum including pericytes and basement membrane of the human saphenous vein (SV) harvested with either conventional (CON) or no-touch (NT) technique for coronary artery bypass grafting. Scanning electron microscope data shows the general damage to vasa vasorum of CON-SV, while the transmission electron microscope data presents ultrastructural features of the vasa in more detail. Hence there are some features suggesting pericyte involvement in the contraction of vasa blood vessels, particularly in CON-SV. Other features associated with the vasa vasorum of both CON-SV and NT-SV preparations include thickened and/or multiplied layers of the basement membrane. In some cases, multiple layers of basement membrane embrace both pericyte and vasa microvessel making an impression of a "unit" made by basement membrane-pericyte-endothelium/microvessel. It can be speculated that this structural arrangement has an effect on the contractile and/or relaxing properties of the vessels involved. Endothelial colocalization of immunoreactive inducible nitric oxide synthase and endothelin-1 can be observed (with laser confocal microscope) in some of the vasa microvessels. It can be speculated that this phenomenon, particularly of the expression of inducible nitric oxide synthase, might be related to structurally changed vasa vessels, e.g., with expanded basement membrane. Fine physiological relationships between vasa vasorum endothelium, basement membrane, pericyte, and perivascular nerves have yet to be uncovered in the detail needed for better understanding of the cells'specific effects in SV preparations for coronary artery bypass grafting.

[Endoscopic vessel (radial artery and/or vein) : harvesting for coronary bypass grafting]

We report the technique of endoscopic vessel (radial artery and/or vein) harvesting for coronary bypass grafting. Clearly less invasive, this endoscopic approach therefore offers the following advantages for the patient: limited postoperative pain and therefore faster rehabilitation in terms of mobility, less postoperative care, the absence of a long scar and therefore a lower risk of surgical complications with a better aesthetic result, while allowing a quality and a permeability of the graft similar to those obtained after a classic surgical harvest.

Ambulatory surgery for chronic venous insufficiency using radiofrequency thermoablation: quality and satisfaction

BACKGROUND

Chronic venous disease is a frequent and prevalent pathology. Its surgical treatment has been shown to be cost-effective. Thermal endoablation performed as major outpatient surgery (MAS) is the technique of choice.

OBJECTIVE

To know the satisfaction of patients after MAS and the quality of care provided.

METHOD

Observational, descriptive, cross-sectional study, carried out between January 2019 and March 2020. A survey was carried out on patients who underwent endovascular radiofrequency thermoablation in two hospitals in Spain, consisting of two questionnaires: one ad hoc and one another of satisfaction (SERCAL). Quality indices for MAS were measured.

RESULTS

We analyzed 156 episodes. 145 interventions were carried out. We found 4 (2.8%) unscheduled admissions. 3 patients (2.1%) attended the emergency department. There was a 99.3% success rate. 100% of the patients had pre-surgical recommendations and informed consent. We obtained 48 surveys (response rate: 33.1%). All the patients gave a rating greater ≥ 8 in quality of care (x = 9.83) and would recommend this procedure to their relatives (x = 9.71).

CONCLUSIONS

Endovascular radiofrequency thermoablation performed in MAS has a high success rate and a very low rate of admission and visit to the emergency room. Patient satisfaction is high.

A Case of Using No-Touch Saphenous Vein Graft in Redo CABG after Multiple Failed Percutaneous Coronary Interventions

The modality of repeat revascularization due to late graft failure is a debated topic. The latest available European guidelines recommend redo coronary artery bypass graft (CABG) for cases of extensively diseased and/or occluded grafts and those with diffuse native vessel disease. We present the case of a patient being relieved of recurrent unstable angina pectoris with redo CABG using no-touch saphenous vein grafts after repeated and unsuccessful attempts with percutaneous coronary intervention (PCI). This could be an alternative to PCI in patients with a complex medical history. Teamwork between cardiologists and surgeons is pivotal in deciding the best treatment modality.

A Brief Comment on Vasa Vasorum of Human Saphenous Vein: relevance for Coronary Artery Bypass Surgery

The importance of the vasa vasorum and blood supply to the wall of human saphenous vein (hSV) used for coronary artery bypass grafting (CABG) is briefly discussed. This is in the context of the possible physical link of the vasa vasorum connecting with the lumen of hSV and the anti-ischaemic impact of this microvessel network in the hSV used for CABG.

Saphenous Vein Vasa Vasorum as a Potential Target for Perivascular Fat-Derived Factors

Perivascular adipose tissue (PVAT) is a source of factors affecting vasomotor tone with the potential to play a role in the performance of saphenous vein (SV) bypass grafts. As these factors have been described as having constrictor or relaxant effects, they may be considered either beneficial or detrimental. The close proximity of PVAT to the adventitia provides an environment whereby adipose tissue-derived factors may affect the vasa vasorum, a microvascular network providing the vessel wall with oxygen and nutrients. Since medial ischaemia promotes aspects of graft occlusion the involvement of the PVAT/vasa vasorum axis in vein graft patency should be considered.

COVID-19 - Endothelial Axis and Coronary Artery Bypass Graft Patency: a Target for Therapeutic Intervention?

It has been reported that severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) infection induces endothelial inflammation, therefore facilitating the progression of endothelial and vascular dysfunction in coronavirus disease 2019 (COVID-19) patients. Coronary artery bypass grafting (CABG) involves mainly the use of the saphenous vein (SV) and internal mammary artery as graft material in the stenosed coronary arteries. Unfortunately, graft patency of the SV is low due to endothelial dysfunction and inflammation. We propose that SARS-CoV-2 might cause vascular inflammation, endothelial dysfunction, and thrombosis in coronary artery bypass graft vessels by binding angiotensin-converting enzyme 2 receptor. Therefore, in this Special Article, we consider the potential influence of COVID-19 on the patency rates of coronary artery bypass graft vessels, mainly with reference to the SV. Moreover, we discuss the technique of SV graft harvesting and the therapeutic potential of focusing on endothelial dysfunction, vascular inflammation, and thrombosis for protecting coronary artery bypass grafts in COVID-19 infected CABG patients.

Twenty-Five Years of No-Touch Saphenous Vein Harvesting for Coronary Artery Bypass Grafting: Structural Observations and Impact on Graft Performance

The saphenous vein is the most common conduit used in coronary artery bypass grafting (CABG) yet its failure rate is higher compared to arterial grafts. An improvement in saphenous vein graft performance is therefore a major priority in CABG. No-touch harvesting of the saphenous vein is one of the few interventions that has shown improved patency rates, comparable to that of the left internal thoracic artery. After more than two decades of no-touch research, this technique is now recognized as a Class IIa recommendation in the 2018 European Society of Cardiology and the European Association for Cardio-Thoracic Surgery guidelines on myocardial revascularization. In this review, we describe the structural alterations that occur in conventional versus no-touch saphenous vein grafts and how these changes affect graft patency. In addition, we discuss various strategies aimed at repairing saphenous vein grafts prepared at conventional CABG.

Why Use the Radial Artery? The Saphenous Vein is the Second Graft of Choice for CABG in Brazil

The saphenous vein (SV) is the most commonly used conduit for coronary artery bypass surgery (CABG) and the second conduit of choice in Brazil and many other countries. The radial artery (RA) is suggested, by some, to be superior to SV grafts, although its use in the USA declined over a 10 year period. The patency of SV grafts (SVG) is improved when the vein is harvested with minimal trauma using the no-touch (NT) technique. This improved performance is due to the preservation of the outer pedicle surrounding the SV and reduction in vascular damage that occurs when using conventional techniques (CT) of harvesting. While the patency of NT SVGs has been shown superior to the RA at 36 months in one study, data from the RADIAL trial suggests the RA to be the superior conduit. When additional data using NT SVG is included in this trial the difference in risk of graft occlusion between the RA and SV grafts dissipates with there no longer being a significant difference in patency between conduits. The importance of preserving SV structure and the impact of NT harvesting on conduit choice for CABG patients are discussed in this short review.

The Predictive Effects of Clinical Hematological Changes on Saphenous Graft Patency after Coronary Artery Surgery

Objectives

To investigate the association between clinical hematologic parameters and saphenous vein graft failure after on-pump coronary artery bypass surgery.

Methods

A total of 1950 consecutive patients underwent isolated on-pump coronary artery surgery between November 2010 and February 2013. Of these, 284 patients met our inclusion criteria; their preoperative clinical hematological parameters were retrospectively obtained for this cohort study. And of them, 109 patients underwent conventional coronary angiography after graft failure was revealed by coronary computed tomography angiography. The primary endpoint was to catch at least one saphenous vein graft stenosis or occlusion following the coronary angiogram. We then analyzed risk factors for graft failure. In sequential or T grafts, each segment was analyzed as a separate graft.

Results

In logistic regression analysis, older age, platelet distribution width, and diabetes mellitus were identified as independent predictors of saphenous vein graft failure (P<0.). In contrast, preserved ejection fraction value favored graft patency (P<0.001).

Conclusion

Increased platelet distribution width is easily measurable and can be used as a simple and valuable marker in the prediction of saphenous vein graft failure.

Effects of in vitro Amitriptyline, Fluoxetine, Tranylcypromine and Venlafaxine on Saphenous Vein Grafts

Objective

In this study, we aimed to examine the effects of amitriptyline, fluoxetine, tranylcypromine and venlafaxine on saphenous vein grafts in coronary artery bypass graft surgeries.

Methods

59 patients (40 males and 19 females; mean age 65.1 years, distribution: 45-84 years) who had coronary artery bypass graft surgery between February 2014 and May 2016 were included in the study. After the saphenous vein grafts with intact and denuded endothelium were precontracted with 3×10^-6M phenylephrine, amitriptyline, fluoxetine and tranylcypromine were cumulatively added to isolated organ baths in the range of 10^-11-3x10^-5M, while venlafaxine was added in the range of 10^-9-3×10^-5M. Then, the antidepressant-induced relaxation responses were recorded isometrically.

Results

While the relaxation response of amitriptyline at -6.42 (Log M) was 74.6%, the response at -6.32 (Log M) was 75.5%. While the relaxation response at -6.46 (Log M) of fluoxetine was 68.02%, the response at -6.02 (Log M) was 72.12%. While the relaxation response of tranylcypromine at -7.53 (Log M) was 61.13%, the response at -7.23 (Log M) was 65.53%. While the relaxation response of venlafaxine at -6.21 (Log M) was 29.98%, the response at -5.90 (Log M) was 32.96%.

Conclusion

The maximum relaxation at minimum and maximum therapeutic concentrations was obtained with amitriptyline, fluoxetine and tranylcypromine, and the minimum relaxation was obtained with venlafaxine. The relaxation responses were independent of the endothelium.

Different expression of Micro RNA-126, 133a and 145 in aorta and saphenous vein samples of patients undergoing coronary artery bypass graft surgery

Introduction: microRNAs (miRNAs) are highly conserved, noncoding RNA molecules that regulate gene expression on the post-transcriptional level. Some evidence indicates that microRNAs dysfunction plays a crucial role in human disease development. The role of microRNAs in cardiac growth, hypertrophy, heart failure, cardiovascular complications in diabetes and many other hearth conditions are demonstrated. In this study we aimed to evaluate the expression of six microRNAs (mir-100, mir-126, mir-127, mir-133a, mir-133b and mir-145) that have been shown to overexpress in aortic and carotid plaques.

Methods: Thirty Coronary Artery Disease patients who underwent elective coronary artery bypass graft surgery were enrolled in the study. The expression patterns of six miRNAs (mir-100, mir-126, mir-127, mir-133a, mir-133b, and mir-145) were examined in 30 patients of whom we obtained aorta and saphenous vein samples.

Results: In three miRNAs, mir-100, mir-127 and mir-133b, we did not obtain expression data from real-time experiments. We found that the expression level of mir-126, mir-133a and mir145 were lower in aorta in comparison with saphenous vein. Mir-126 was highly expressed in saphenous vein samples (13.8±1.1) when compared with aorta samples (20.2±1.1), although mir133a was highly expressed in saphenous vein samples (16.1±0.5) when compared with the aorta (17.9±1.5). Expression of mir-145 saphenous vein samples was also dramatically higher than aorta (7.2±0.5 versus 10.8±0.6) that was statistically significant (P<0.05).

Conclusion: Understanding the role of miRNAs in cardiovascular physiology and diseases might suggest miRNA- based therapeutic methods in the management of coronary artery disease.

Factors associated with the no-reflow phenomenon following percutaneous intervention of saphenous vein coronary bypass grafts

BACKGROUND

We investigated clinical and procedural factors associated with the no-reflow phenomenon following percutaneous coronary intervention (PCI) of the saphenous-vein grafts (SVG).

METHODS

A cross-sectional study was done on patients who had undergone PCI of the SVG. Patients' medical documents were reviewed for demographic, clinical, laboratory, and procedural data. Slow/no-reflow was defined based on the thrombolysis in myocardial infarction (TIMI) grade (0 to 2). Univariate and multiple logistic regression analyses were performed to investigate factors associated with slow/no-reflow and P < 0.050 was considered as significant.

RESULTS

A total of 205 patients were studied (81% man, mean ± standard deviation of age was 66.8 ± 9.6 years). Slow/no-reflow was found in 38 (18.5%) patients. High diastolic blood pressure (P = 0.010), leukocytosis (P = 0.017), diffuse lesions (P = 0.007), degenerated SVG (P < 0.001), proximal lesions (P < 0.001), thrombosis (P = 0.013), and lower number of used stents during procedure (P = 0.032) were associated with slow/no-reflow in unadjusted analyses. Factors independently associated with slow/no-reflow were pre-procedural high diastolic blood pressure with odds ratio (OR) = 3.858 [95% confidence interval (95% CI), 1.157-12.860], degenerated SVG with OR = 5.901 (95% CI: 1.883-18.492), proximal lesions with OR = 5.070 (95% CI: 1.822-14.113), pre-intervention TIMI grade with OR = 0.618 (95% CI: 0.405-0.942), number of used stents for PCI with OR = 0.074 (95% CI: 0.011-0.481) for > 1 stent, and length of stents used for PCI with OR = 0.100 (95% CI: 0.019-0.529) for > 30 mm stents.

CONCLUSION

This study on the clinical and procedural factors associated with the slow/no-reflow phenomenon following PCI of the SVG can be used in risk estimation of this serious complication and tailoring preventive strategies to at-risk patients.

Fatty acids composition of aorta and saphenous vein tissues in patients with coronary artery diseases

Introduction: Considering importance of fatty acids in developing coronary artery disease (CAD) and lack of information about saphenous vein which is commonly used as coronary arterial bypass, in this study we investigated differences in fatty acids composition between saphenous vein and aorta tissues in patients with CAD.

Methods: Biopsy samples of aortic tissues and saphenous veins as well as blood samples were obtained form 42 patients with CAD. Fatty acids composition of the tissues was determined using gas chromatography and also serum lipid profile was evaluated by commercial kits.

Results: Levels of palmitic acid (16:0) were significantly higher in aorta in compared with saphenous (P < 0.001). Also levels of most unsaturated fatty acids (16:1, 18:1n-9, 18:1t, 18:2t, 18:3 n‐9 and 22:3n-3) were statistically higher in saphenous tissue than aorta tissue (P < 0.05). Mean levels of linoleic acid (18:2 n-6) was higher in aorta tissue in comparison with saphenous tissue (P = 0.01). We observed positive correlations between serum levels of LDL-C with elaidic acid and linoleic acid levels in saphenous. Evaluation of aorta tissue fatty acids revealed that palmitoleic acid (16:1) had positive and arachidonic and linoleic acids had negative correlations with serum HDL-C levels.

Conclusion: Our results revealed difference between fatty acids composition of aorta and saphenous vein tissues and existence of correlations between the fatty acids levels with serum lipid profile. The saphenous vein had higher poly-unsaturated fatty acids in compared to aorta tissue and thus this vein is not at risk of atherosclerosis and can be used as coronary arterial bypass.

Prophylactic GSV surgery in elderly candidates for hip or knee arthroplasty

Aging is one of the major risk factors for varicose veins. The same is for Knee and Hip Osteoarthritis. Most of the patients undergoing to Hip (THA) or Knee (TKA) arthroplasty are over sixteen. Varicose veins, excluding thrombophilia, are the most significant risk factors for VTE after THA and TKA. This study investigates on the usefulness of prophylactic treatment of GSV insufficiency in elderly patients undergoing to orthopedic surgery. A retrospective study enrolling 44 over-sixty five patients, undergoing to TKA or THA. 24 patients underwent to traditional surgery and 20 to EVLA. The presence of evident varicosities and/or a saphenic reflux lasting > 500 ms has been considered as operability criterion. Both in surgery and EVLA group has been performed the ablation of visible varicosities and only saphenic refluxing traits.

RESULTS

1 case of symptomatic DVT was recorded after arthroplasty. A statistically significant difference (p = 0.006) of recovery time between surgery and EVLA groups has been detected. There is not a statistically significant difference in long-term recurrence rate between surgery and EVLA.

CONCLUSIONS

It is useful to program GSV surgery, before treat hip or knee. This study showed a 50% decrease in the incidence of postoperative DVT.

Saphenous vein graft aneurysm: A case report

BACKGROUND

Saphenous vein graft aneurysms (SVGAs) are rare seen issues after coronary artery bypass graft (CABG) operation which may lead to major complications including compression of adjacent structure, myocardial ischemia, rupture, and even death.

CASE REPORT

We report a patient with recurrent SVGA and its treatment by percutaneous intervention with a covered stent, the diagnostic and treatment procedure were based on contrast enhanced computed tomography and myocardial perfusion scintigraphy (MPS).

CONCLUSION

Multimodality imaging is required to demonstrate the true size and complications of the SVGA, the relationship among the adjacent structure, and to assess ischemia and size of myocardial territory supplied by the aneurysmal graft to decide treatment strategy.

Vasorelaxant effect of 17α-ethynylestradiol on human saphenous vein

PURPOSE

A protective effect for estrogens against cardiovascular problems has long been known. The aim of this study was to investigate the vasorelaxant effect of 17α-Ethynylestradiol (17α-EE) on human saphenous vein.

METHODS

The veins were suspended horizontally between two triangular stainless steel hooks for the measurement of isometric tension in individual organ baths containing 10ml Krebs solution, at 37°C and gassed with carbogen under 3gr optimum tension. The effect of different concentrations of 17α-EE (2-40 μM) on vascular tone was investigated in veins precontracted with PGF2α. Relaxation was measured after 40min and expressed as the percent decrease of initial contraction. To determine the involvement of potassium channels, endothelium, nitric oxide synthase, guanylylcyclase and prostaglandins in the vasorelaxant effect of estrogen, the veins were incubated with tetraethyl ammonium, N-nitro-L-arginine methyl ester, methylene blue or indomethacin, respectively for 20min prior to experimentation. Responses to 17α-EE were directly compared to those obtained in the same tissues in the absence of the inhibitors.

RESULTS

The mean relaxations induced by 17α-EE with concentrations of 2, 5, 10, 20 and 40μM in tissues precontracted with PGF2α were 19.8 ±5.5%, 26.1±10.8%, 32.2±7.4%, 48.6±10.8%and56±7.6%, respectively. The results of the inhibition of potassium channels, nitric oxide synthase, guanylylcyclase, cyclooxygenase and removing endothelium in relaxation induced by 17α-EE on precontracted veins with PGF2α proved no significant differences.

CONCLUSION

This study showed that 17α-EE has significant vasorelaxant effect on human saphenous vein in a concentration-dependent manner. This effect is probably independent of potassium channels, nitric oxide synthase, guanylylcyclase, prostaglandin synthesis and endothelium functions.

Mid-Term Patency in Radial Artery and Saphenous Vein After Coronary Artery Bypass Grafting in Asymptomatic Patients Using 128-Slice CT Coronary Angiography

Background:

Patency of the revascularization conduit is an essential predictor of long-standing survival after coronary artery bypass grafting.

Objectives:

We have conducted this study to compare the mid-term patency rates of radial artery (RA), left internal thoracic artery (LITA) and also saphenous vein (SV) grafts in asymptomatic patients following coronary artery bypass graft surgery (CABG) undergoing total IV anesthesia.

Patients and Methods:

In this study, 30 three-vessel disease patients with 104 RA, LITA, and SV grafts used concomitantly for primary isolated non-emergent CABG surgery were assessed. The primary end point was CT angiographic graft patency rate. After 53.5 (24-97) months’ follow-up, graft patency was assessed using 128-slice CT coronary angiography. Logistic regression analysis was used to detect the independent predictors of graft failure.

Results:

A total of 104 grafts, including 30 LITA, 44 SV, and 30 RA grafts, were studied. Cumulative graft patency rates were 93.3% in LITA, 83.3% in RA, and 70.5% in SV grafts. Statistically significant difference was found between the LITA and the SV graft patency rates (P = 0.019), whereas the difference between the RA conduit patency and the LITA or SV graft patency rates did not have any statistical significance (P = 0.424 and P = 0.273, respectively). Independent predictors of RA grafts occlusion were native coronary stenosis < 70% and female gender.

Conclusions:

In our patients, the RA grafts had an acceptable patency rate in 2 to 5 years’ follow-up. Although the SV grafts had a relatively higher patency rate than RA grafts in our asymptomatic patients, the patency rates in RA and SV grafts were close to each other. The RA graft function was poor in the patients with a higher number of risk factors and in the females.

Early and midterm major adverse cardiac events in patient with saphenous vein graft using direct stenting or embolic protection device stenting

Background:

The treatment of an occluded saphenous vein graft (SVG) with percutaneous coronary intervention may encounter major adverse cardiac events (MACE). MACE rates have been reduced significantly by using the embolic protection device (EPD).

Objectives:

The aim of this study was to clarify the risks and the benefits of embolic protection devices.

Patients and Methods:

In a prospective, non-randomized observational study, patients aged 33 to 85 years old who underwent elective percutaneous coronary intervention due to SVG stenosis at our tertiary care center were enrolled between 2009 and 2011. The incidence rates of adverse events, including MACE, were obtained during the patients’ hospitalization and at 30-day and 6-month follow-up. MACE included death, Q-wave and non-Q-wave myocardial infarction, in-stent thrombosis, target lesion revascularization, and target vessel revascularization.

Results:

From 150 patients enrolled to the study, 128 (85.3%) patients underwent direct stenting and the rest underwent the EPD procedure. In-hospital MACE occurred in 17.2% of the patients in the direct stenting group versus only 9.1% in the EPD group (P = 0.530). MACE incidence was gradually increased at one and 6-month follow-up periods in the direct stenting group (19.5% and 21.9%, respectively), and remained unchanged in the EPD group (9.1% at six-month follow-up). Multivariate logistic regression model showed that the stenting procedure type could not predict early and midterm MACE with the presence of baseline characteristics as cofounders.

Conclusions:

Despite the considerable lower early and midterm MACE rates, numerically following the EPD procedure compared to direct stenting, the difference in the MACE rates between the two groups was not significant.

Vascular injuries: trends in management

ABSTRACT

Vascular injury presents a great challenge to the emergency resident because these injuries require urgent intervention to prevent loss of life or limb. Sometimes serious vascular injury presents with only subtle or occult signs or symptoms. The patient may present weeks or months after initial injury with symptoms of vascular insufficiency, embolization, pseudoaneurysm, arteriovenous fistula etc. Although the majority of vascular injuries are caused by penetrating trauma from gunshot wounds, stabbing or blast injury, the possibility of vascular injury needs to be considered in patients presenting with displaced long bone fractures, crush injury, prolonged immobilization in a fixed position by tight casts or bandages and various invasive procedures. iatrogenic vascular injuries constitute about 10% of cases in most series; however the incidence is an increasing trend because more endovascular procedures such as angioplasty and cardiac catheterization are being performed routinely. Civilian trauma is more frequently seen in young males. However, it can occur at any age due to road accidents, firearms, bomb blasts and diagnostic procedures. Most of the time, civilian trauma causes less tissue damage. There is an epidemic of vascular injuries in Kashmir valley because of problems in law and order in the past two decades. This review deals with the topic in detail.