Purpose: In this article, we reported on the up-to-date literature regarding skeletonized bilateral internal mammary artery (BIMA) flow and the effect on sternal perfusion. We also reviewed the pros ...and cons of the skeletonization technique versus the conventional pedicle technique for harvesting the BIMA.Methods: We performed an up-to-date review using the PubMed database, with a specific focus on the contemporary published literature.Results: BIMA skeletonization can preserve the sternal microcirculation, minimize tissue damage, and maintain blood supply to the chest wall at the tissue level. This effect is also apparent in diabetics. Deep sternal wound infection (DSWI) rates are significantly less with skeletonization versus the conventional pedicle technique and are comparable to single internal mammary artery harvesting.Conclusions: Contemporary large-scale studies demonstrate that skeletonization of the BIMA increases conduit length, provides superior flow, reduces the incidence of DSWIs, and improves late survival. Hopefully, this review will increase awareness of the compelling evidence in favor of using skeletonized internal mammary arteries and stimulate increased uptake of BIMA revascularization surgery.
The right internal mammary artery (RIMA) has been considered the second-best graft after the left internal mammary artery by many. Recent guidelines have awarded class IIa recommendation for using ...the RIMA. The findings of the Cardiovascular Outcomes for People Using Anticoagulation Strategies (COMPASS)—coronary artery bypass grafting (CABG) sub-study showed a high graft failure rate for the RIMA. The findings of the study should initiate further scientific scrutiny of the RIMA and studies need to be carried out for further evaluation of the RIMA as a conduit.
A best evidence topic was constructed according to a structured protocol. The question addressed was whether the configuration of bilateral internal thoracic arteries (BITAs) influences survival, ...patency or repeat revascularization in patients undergoing coronary artery bypass grafting. Five hundred and seventy-one papers were found using the reported searches, of which 8 represented the best evidence to answer the clinical question. One systematic review, 4 randomized trials and 3 observational studies were selected. The authors, date, journal, study type, population, main outcome measures and results are tabulated. All 4 prospective randomized trials found no significant difference in graft patency or mortality when comparing Y-graft and in situ configurations. Three of the 4 randomized trials found no difference in major adverse cardiovascular and cerebrovascular events or repeat revascularization at follow-up. An exception was Glineur et al. (Bilateral internal thoracic artery configuration for coronary artery bypass surgery: a prospective randomized trial. Circ Cardiovasc Interv 2016;9:7), who found that the Y-configuration resulted in lower rates of major adverse cardiovascular and cerebrovascular events. All 3 observational studies reviewed found no alteration in survival, cardiac events or repeat revascularization between in situ and Y-graft BITA configurations. One systematic review found similar outcomes with respect to mortality, cardiac events and repeat revascularization with in situ and composite BITA. In summary, existing literature demonstrates no difference in clinical outcomes between composite and in situ graft configurations. Furthermore, the configuration of BITA does not affect mortality, graft patency or repeat revascularization.
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Neointimal hyperplasia, which results from the activation, proliferation and migration of vascular smooth muscle cells (SMCs), is a detrimental condition for vascular stents or ...vascular grafts that leads to stenosis. Preventing neointimal hyperplasia of vascular grafts is critically important for the success of arterial vascular grafts. We hypothesized that tropoelastin seeding onto the luminal surface of the graft would prevent neointimal hyperplasia through suppressing neointimal smooth muscle cell proliferation. In this study, we investigated the efficacy of tropoelastin seeding in preventing neointimal hyperplasia of bioresorbable arterial vascular grafts. Poly (glycolic acid) (PGA) fiber mesh coated with poly (l-lactic-co-ε-caprolactone) (PLCL) scaffolds reinforced by poly (l-lactic acid) (PLA) nano-fibers were prepared as bioresorbable arterial grafts. Tropoelastin was then seeded onto the luminal surface of the grafts. Tropoelastin significantly reduced the thickness of the intimal layer. This effect was mainly due to a substantial reduction the number of cells that stained positive for SMC (α-SMA) and PCNA in the vessel walls. Mature elastin and collagen type I and III were unchanged with tropoelastin treatment. This study demonstrates that tropoelastin seeding is beneficial in preventing SMC proliferation and neointimal hyperplasia in bioresorbable arterial vascular grafts.
Small resorbable vascular grafts can block due to the over-proliferation of smooth muscle cells in neointimal hyperplasia. We show here that the proliferation of these cells is restricted in this type of graft.
This is achieved with a simple dip, non-covalent coating of tropoelastin. It is in principle amendable to other grafts and is therefore an attractive process.
This study is particularly significant because: (1) it shows that smooth muscle cell proliferation can be reduced while still accommodating the growth of endothelial cells, (2) small vascular grafts with an internal diameter of less than 1mm are amenable to this process, and (3) this process works for resorbable grafts.
Listeria monocytogenes may cause serious vascular and graft infections. In the present case report, a 71-year-old man underwent partial prosthetic endograft replacement due to high-flow endoleak and ...limb occlusion. Following surgery, a multiple empiric antibiotic regime was initiated due to fever, malaise, abdominal tenderness and signs of an acute abdomen; however, in spite of this, the clinical condition of the patient worsened. An aorto-enteric fistula was discovered, and duodenal resection with duodeno-jejunal anastomosis packaging was performed. Gastrointestinal bleeding originating from this anastomosis both complicated and prolonged the clinical course, necessitating appropriate parenteral support and endoscopic hemostasis. The growth of Candida lusitanae in the drained abdominal and pleural effusion, and the isolation of L. monocytogenes from the thrombus inside the removed abdominal aorto-bi-iliac endograft allowed for establishment of a specific antibiotic treatment. After a suitable period of clinical improvement, the patient was transferred to a clinical rehabilitation center. At the present time, the patient maintains a good condition. To the best of our knowledge, the present study represents the first described case of thrombotic infection of an aorto-bi-iliac endograft by L. monocytogenes. In the event of graft thrombotic occlusion, L. monocytogenes infection should be considered as a potential cause. In case of complications requiring open conversion, even if not suspected from the medical history of the patient, the possibility of an underlying and occult infection should always be excluded with an in-depth preoperative work-up.
Late survival of patients having deep sternal wound infection (DSWI) after bilateral internal thoracic artery (BITA) grafting is largely unexplored.
Outcomes of 3391 consecutive BITA patients were ...reviewed retrospectively. Patients with DSWI after surgery (n = 142, 4.2%) were compared with those having no sternal complications (n = 3177). Predictors of DSWI and of mortality during the follow-up period were found with negative-binomial and Cox proportional-hazards regression, respectively. One-to-one propensity score-matched analysis, which considered simultaneously baseline patient characteristics, operative data, and postoperative complications was performed. The resulting matched pairs were compared for non-parametric estimates of late survival. The same comparison was performed in matched pairs having no major complications (except DSWI) early after surgery.
In-hospital mortality was higher in DSWI cohort than in patients having no sternal complications (5.6% vs. 1.8%, p = 0.0035). Almost all of postoperative complications were more frequent in DSWI patients. Female sex, obesity, chronic lung disease, renal impairment, extracardiac arteriopathy, congestive heart failure, and urgent/emergency priority were predictors of DSWI common to two DSWI risk models that were developed. DSWI was independent predictor of reduced late survival (multiple covariates-adjusted hazard ratio HR, 1.91, p < 0.0001). The propensity matching resulted in 135 pairs with same in-hospital mortality (5.2%). Estimates of freedom from all-cause death were lower in DSWI cohort (HR, 1.92, p < 0.0001), even when only pairs (n = 59) having no major postoperative complications (except DSWI) were considered (HR, 1.84, p = 0.026).
DSWI after BITA use seems to reduce late survival even after adjusting for baseline patient characteristics and concomitant postoperative complications.
•Bilateral internal thoracic artery (BITA) grafting is underused primarily because of increased risk of sternal complications.•Deep sternal wound infection (DSWI) is associated with increased morbidity and mortality after surgery.•To date, late survival of patients having DSWI after BITA grafting is largely unexplored.•Based on the results of this study, DSWI in BITA patients seems to be independent predictor of reduced late survival.
The surgical management of acute and chronic complex diseases involving the aortic arch and the descending thoracic aorta remains challenging. Hybrid procedures associating total open arch ...replacement and stent-grafting of the proximal descending aorta were developed to allow a potential single-stage treatment, promote remodeling of the downstream aorta, and facilitate a potential second-stage thoracic endovascular aortic repair by providing an ideal landing zone. While these approaches initially used various homemade combinations of available conventional prostheses and stent-grafts, the so-called frozen elephant trunk technique emerged with the development of several custom-made hybrid prostheses. The aim of this study was to review the contemporary outcomes of this technique in the management of complex aortic diseases, with a special focus on procedural planning, organ protection and monitoring, refinements in surgical techniques, and long-term follow-up.
Tubularized graft urethroplasty fails largely because of inadequate graft take. Prefabrication of buccal mucosa lined flap has theoretical indications for constructing neourethra with an independent ...blood supply. The efficacy of using a tissue expander capsule as an induced vascular bed to prefabricate an axial vascularized buccal mucosa-lined flap for tubularized urethral reconstruction in a rabbit model was tested. The experiments were performed in three stages. First, silicone tissue expanders were inserted into the groin to induce vascularized capsule pouch formation. Next, buccal mucosa grafts were transplanted to the newly formed capsular tissue supplied by the axial vessel for buccal mucosa-lined flap prefabrication. Then, circumferential urethral defects were created and repaired by buccal mucosa graft (Group 1), capsule flap (Group 2) and prefabricated capsule buccal mucosa composite flap (Group 3). With retrograde urethrography, no rabbits in Group 1 maintained a wide urethral caliber. In Group 2, the discontinued epithelial layer regenerated at 1 month, and the constructed neourethra narrowed even though the lumen surface formed intact urothelial cells at 3 months. In Group 3, buccal mucosa formed the lining in the neourethra and kept a wide urethral caliber for 3 months. The capsule may serve as an induced vascular bed for buccal mucosa-lined flap prefabrication. The prefabricated buccal mucosa-lined flap may serve as a neourethra flap for circumferential urethral replacement.
Aneurysms are common vascular diseases which affect normal haemodynamics in the aorta. Endovascular aortic repair (EVAR) using stent-grafts is a common treatment that excludes the aneurysm from the ...circulation, preventing further growth and eventual rupture. However, complications such as endoleak, dislocation or limb occlusion have been reported after EVAR. This study hypothesized that the compliance mismatch between the graft and parent artery causes haemodynamic disturbances at the distal edge of the graft. Therefore, the potential for the graft to cause limb occlusion was assessed. A compliant phantom was fabricated. A circulatory loop was developed to run the fluid and generate a physiological flow waveform. Particle Image Velocimetry was utilised to capture fluid dynamics in the replica. The result showed a low velocity region at the graft trailing edge wall. The low velocity boundary layer thickness decreased downstream of the graft. A flow recirculation was initiated and increased in size during the mid-acceleration at the low velocity region. Shear stresses fluctuated at the trailing edge of the graft which is a risk factor for intimal thickening followed by graft or limb occlusion. It was concluded that this haemodynamic behaviour was due to the graft and parent artery compliance mismatch.
Cardiovascular diseases such as coronary heart disease often necessitate the surgical repair using conduits. Although autografts still remain the gold standard, the inconvenience of harvesting and/or ...insufficient availability in patients with atherosclerotic disease has given impetus to look into alternative sources for vascular grafts.
There are four main techniques to produce tissue-engineered vascular grafts (TEVGs): i) biodegradable synthetic scaffolds; ii) gel-based scaffolds; iii) decellularised scaffolds and iv) self-assembled cell-sheet-based techniques. The first three techniques can be grouped together as scaffold-guided approach as it involves the use of a construct to function as a supportive framework for the vascular graft. The most significant advantages of TEVGs are that it possesses the ability to grow, remodel and respond to environmental factors. Cell sources for TEVGs include mature somatic cells, stem cells, adult progenitor cells and pluripotent stem cells.
TEVG holds great promise with advances in nanotechnology, coupled with important refinements in tissue engineering and decellularisation techniques. This will undoubtedly be an important milestone for cardiovascular medicine when it is eventually translated to clinical use.
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