Vascular Conduits Research Articles

Preimplantation processing of ex vivo‐derived vascular biomaterials: Effects on peripheral cell adhesion

The use of ex vivo-derived scaffolds as vascular conduits has shown to be a clinically valid approach to repair or bypass occluded vessels. Implantation of allogeneic tissue grafts requires careful processing to lower immunogenicity and prevent bacterial infection. However, the mechanical/chemical treatments used to prepare biological scaffolds can result in significant alterations to the native structure and surface chemistry, which can affect in vivo performance. Of particular importance for vascular grafts are binding interactions between the implanted biomaterial and host cells from the circulation and adjacent vasculature. Here we present a comparison of four strategies used to decellularize allogeneic human umbilical vein (HUV) scaffolds: ethanol/acetone, sodium chloride, sodium dodecyl sulfate (SDS), or Triton X-100. Scanning electron microscopy revealed that all four techniques achieved removal of native cells from both the lumenal and ablumenal surfaces of HUV grafts. Platelets and promyelocytic HL-60 cells showed preferential binding on the more loosely structured ablumenal surface, although low surface coverage was observed overall by peripheral blood cells. Vascular endothelial cell adhesion was highest on HUV decellularized using ethanol/acetone, and significantly higher than on SDS-processed grafts (p = 0.016). Primary cells showed high viability on the lumenal surface regardless of decellularization technique (over 95% in all cases). These results demonstrate the critical effects of various chemical processing strategies on the adhesive properties of ex vivo-derived vascular grafts. Careful application-specific consideration is warranted when selecting a processing strategy that minimizes innate responses (e.g. thrombosis, inflammation) that are often deleterious to graft survival.

Extracranial-intracranial bypass: Resurrection of a nearly extinct operation

Giant intracranial artery aneurysms (GIAAs) are often not amenable to neurosurgical clipping or endovascular coiling. Extracranial-intracranial (EC-IC) bypass, a procedure that has been essentially abandoned for the treatment of intracranial ischemic disease, followed by parent vessel occlusion, is often successful in treating these aneurysms. Vascular surgeons should be familiar with this operation, especially in centers with neurosurgical capability. A retrospective review of patients treated from 1990 to 2010 at New York University Medical Center was performed. Office and hospital records of all patients identified were reviewed with attention to the age and sex of the patient, presenting symptoms, preoperative testing, procedure performed, type of bypass conduit, graft patency, intraoperative and postoperative complications, length of follow-up, and overall outcome. EC-IC bypass was performed using a graft of great saphenous vein (GSV) or radial artery (RA). The vascular surgeon harvested the vascular conduit, tunneled the graft, and performed the extracranial anastomosis, and the intracranial anastomosis was performed by the neurosurgeon. A total of 36 patients (14 men, 22 women) underwent 37 EC-IC bypasses with 34 GSV and three RA grafts. The median age was 57 years (interquartile range, 49-66 years), and the median follow-up was 53 months (interquartile range, 29-77 months). Aneurysm location was the internal carotid artery in 30 patients, the basilar artery in three, and the middle cerebral artery in four. All 37 aneurysms were excluded from the cerebral circulation, with 33 grafts remaining patent at follow-up, as determined by serial cerebral or magnetic resonance angiogram. At follow-up, 33 of 34 of the GSV grafts (88%) and three of three (100%) of the RA grafts were patent. There were two deaths (5.6%), despite patent grafts. Postoperative graft occlusion led to homonymous hemianopsia in one patient and temporary hemiparesis in another (5.6%). Graft occlusions were asymptomatic in two patients. EC-IC bypass is a safe and effective treatment for GIAAs, with acceptable rates of morbidity (5.6%), mortality (5.6%), and graft patency (89.2%). We suggest that the technique described in this report should be routinely used for treatment of GIAAs in centers where neurosurgery and vascular surgery services are available and should be considered a standard procedure in the armamentarium of the vascular surgeon.

The Utility of Recanalized Umbilical Vein Graft to the Hepato-pancreato-biliary Surgeon

The authors recently published their experience of recanalizing umbilical veins in deceased liver donors, with recanalized umbilical veins as vascular conduits for meso-Rex bypass procedures. They have since found recanalized umbilical veins to be an excellent, easy to harvest vascular conduit that can be used for multiple vascular procedures and repair. Here, they report their experience using this vessel for bypass and vascular reconstruction. They have recanalized umbilical veins and used them in a total of 5 Meso-Rex bypasses; 5 pancreaticoduodenectomies; 1 left hepatic trisegmentectomy with right portal vein (PV) resection and reconstruction; 1 right hepatectomy and 1 adrenalectomy, both with partial inferior vena cava (IVC) resection and reconstruction; 1 coronary-Rex bypass shunt for extrahepatic PV thrombosis; and 1 orthotopic liver transplantation with infrahepatic IVC anastomotic dehiscence patched with umbilical vein graft. Umbilical veins were dilated mechanically and used in situ for the meso-Rex bypass surgery; they were ligated in the space of Rex and then dilated ex vivo otherwise to be used as interposition grafts or a vein patch. A total of 15 hepato-pancreato-biliary procedures were done using the recanalized umbilical vein as graft; 2 patients required thrombectomy postoperatively with reexploration, venotomy, thrombectomy with fogarty catheter, and venotomy closure. The umbilical vein graft is a fine vascular conduit and can serve many purposes in hepatobiliary surgery.

PS212. Evaluation of Porcine Dermal Collagen (Permacol) as an Alternative Vascular Conduit for Interposition Grafting in the Presence of Bacterial Contamination in a Rabbit Model

Autogenous vein and PTFE are two common conduits used to bypass arterial injuries. PTFE is prone to infection and subsequent graft failure in contaminated wounds. Biosynthetic materials used as conduit are potentially more resistant to infection than PTFE. The objective of this study is to compare Permacol, a biosynthetic material, to vein as a vascular conduit for arterial repair in the presence of bacterial contamination. Thirty six New Zealand white rabbits were randomized to one of four groups: Permacol or autogenous vein graft, with or without bacterial contamination (n = 9). All groups underwent interposition grafting of the common carotid artery. Grafts were contaminated with Staphylococcus aureus upon completion of surgery. Grafts were then excised at day 42 and segments were collected for histological evaluation and bacterial load measurement. Three animals in the contaminated vein group died within 72 hours of surgery. There were no deaths in the other groups. At 42 days, Permacol demonstrated greater patency than vein in the contaminated groups (P > .05) and equivalent patency in the non-contaminated group. No difference was found between the 2 contaminated groups in the bacterial content of graft material at 42 days. When used as a conduit in a contaminated field, Permacol was equivalent to autogenous vein graft with respect to patency and bacterial contamination. When contaminated, Permacol was associated with better survival rates as compared to autogenous vein. Permacol may function as an alternative to autogenous vein as a vascular conduit.

Abstract 236: Significant Mechanical Puncture Resealing Properties of a Novel (Nano-Composite) Compliant Hemodialysis Access Graft Compared with PTFE Conduit Currently in Clinical Use

Aims: The compliance, non-thrombogenicity and biodurability of POSS-PCU graft have been reported in in vitro studies. In vivo studies reveal high patency rate at 9 months (to be published data). A further application of this graft could be in vascular access, where currently PTFE (polytetrafluoroethylene) is the prosthetic conduit of choice. Resilience to puncture with large guage (15-17Ch) dialysis needles is vital for a graft being used as vascular access conduit. We performed ex-vivo tests to compare this specific property between POSS-PCU and PTFE grafts. Methods: A flow circuit containing human blood was used to mimic the arterial system using a phantom pulse generator. Lengths of test graft (8 - 10 cm) were connected to the circuit and submerged in a 2 litre isotonic (0.9%) saline bath. The pulse generator was set at 80 beats/min. A single 15 Ch dialysis needle was used to puncture the full wall thickness of the graft. Samples of saline bath were taken at distances of 2.5cm and 5cms from the puncture site at 5 minute intervals, for a period of 30 minutes. The concentration of red blood cells (cells/litre) were calculated at each time and location point for each graft being compared. Results: Macroscopically, the POSS-PCU graft ’self-sealed’ within seconds after the initial puncture whereas the PTFE puncture site had not sealed by 30 minutes. There was about 15 times lower concentration of red blood cells seen in the samples with POSS-PCU graft compared with PTFE at both 2.5 and 5cm. POSS-PCU as compared to PTFE leaked less red blood cells over a total of 30 minutes. The results were statistically significant (p<0.0001) when analysed with the Friedman test. Conclusions: A significantly better resilience to needle puncture of POSS-PCU over PTFE graft suggests an improved alternative for vascular access surgery. This may result in safer earlier needling and possibly also reflect better long term durability.

Tissue-Engineered Vascular Grafts for Use in the Treatment of Congenital Heart Disease: From the Bench to the Clinic and Back Again

Since the first tissue-engineered vascular graft (TEVG) was implanted in a child over a decade ago, growth in the field of vascular tissue engineering has been driven by clinical demand for improved vascular prostheses with performance and durability similar to an autologous blood vessel. Great strides were made in pediatric congenital heart surgery using the classical tissue engineering paradigm, and cell seeding of scaffolds in vitro remained the cornerstone of neotissue formation. Our second-generation bone marrow cell-seeded TEVG diverged from tissue engineering dogma with a design that induces the recipient to regenerate vascular tissue in situ. New insights suggest that neovessel development is guided by cell signals derived from both seeded cells and host inflammatory cells that infiltrate the graft. The identification of these signals and the regulatory interactions that influence cell migration, phenotype and extracellular matrix deposition during TEVG remodeling are yielding a next-generation TEVG engineered to guide neotissue regeneration without the use of seeded cells. These developments represent steady progress towards our goal of an off-the-shelf tissue-engineered vascular conduit for pediatric congenital heart surgery.

Abstract 269: Collagen Topographical Patterning Modulates Endothelial Cell Morphology, Gene Expression and Function

Endothelial cells (ECs) exposed to laminar shear stress align in the direction of blood flow and express low levels of adhesion molecules. However, it is unknown whether these biological responses result from shear stress per se, or if they can be recapitulated using topography cues from the underlying extracellular matrix (ECM). We hypothesized that collagen topographical patterning can regulate EC assembly and function in the absence of shear stress. We fabricated collagen-coated polydimethylsiloxane microchannels (30μm wide) to induce EC alignment. When grown on microchannels, the ECs underwent striking re-organization of their actin cytoskeleton (aligned within 10 degrees of the microchannel direction) and their focal adhesions (Fig A). Mimicking the reported EC responses to laminar shear stress, aligned ECs were more quiescent (reduced Ki67 expression), and less adhesive for monocytes (with 50% reductions in the expression of intercellular adhesion molecule 1, and in monocyte adhesion in a functional binding assay). DNA microarrays revealed a transcriptional signature of 600 genes that were differentially expressed by ECs cultured on the patterned substrates (Fig B), including genes previously not associated with EC function such as histones (HIST1H2AH, HIST2H2BF) and heat shock proteins (HSPB7, HSPB9). These results demonstrate that topographical cues from the underlying ECM are potent regulators of EC morphology and function and mimic the effects of laminar shear-stress. This work highlights the importance of cell-ECM interactions in maintenance of EC phenotype and has implications in the design of vascular conduits to minimize atherogenesis.

Pre- and Postoperative Imaging of the Rex Shunt in Children: What Radiologists Should Know

The objective of this article is to illustrate the imaging features of patients with extrahepatic portal venous obstruction who are evaluated before or after a Rex shunt surgery. The Rex shunt is a potentially curative surgical procedure that reestablishes physiologic hepatopetal portal flow. It is typically accomplished by interposing a vascular conduit between the superior mesenteric vein to the still patent intrahepatic portal venous system. This procedure results in resolution of portal hypertension.

Living Donor Liver Transplantation for the Patients With Portal Vein Thrombosis: Use of an Interpositional Venous Graft Passed Posteriorly to the Pancreatic Parenchyma Without Using Jump Graft

BackgroundIt is difficult to reconstruct the portal vein (PV) using a long interpositional venous graft in living donor liver transplant (LDLT) patients with portal vein thrombosis (PVT), which involves the confluence of the superior mesenteric vein (SMV) and splenic vein (SV). We successfully performed LDLT for three patients with PVT using an interpositional vascular conduit passing posterior to the pancreas without a jump graft. MethodsThree of 130 patients who underwent LDLT in our hospital between March 2002 and June 2011 required this technique. After indentifying the location of the SMV, SV and gastrocolic trunk, we ligated and cut the posterior superior pancreaticoduodenal vein and other short branches from the PV. The PV was drawn inferiorly to the pancreas and transected at the confluence of SMV and SV. The external iliac vein or internal jugular vein was sacrificed as a graft for anastomosis to the cut end of the SMV using 6-0 polypropylene running sutures. Then the venous graft was drawn superiorly to the pancreas by passing it posterior to the pancreas parenchyma for anastomosis to the liver graft PV. The interpositional vein was placed posterior to the pancreas where the PV used to be. ResultsAll three patients displayed favorable postoperative courses with the Doppler ultrasound demonstrating good portal flow perioperatively. The postoperative portogram demonstrated patency of the vascular graft. ConclusionThis method is easy and helpful to treat portal vein thrombosis, by providing the shortest route between the PV of the donor and the SMV of the recipient.

Salvage of infected vascular graft via ‘perivascular venous banding’ technique coupled with rectus abdominis myocutaneous muscle flap transposition

This is the case of a severe Pseudomonas aeruginosa biological vascular graft infection, completely involving the perianastomotic tract of a femoro - femoral crossover bypass and resulting in repeated bleeding from the offended vessel wall. After the failure of a sartorious rotational muscle flap transposition into the infected groin wound, this 'high-grade' vascular graft infection was finally treated successfully by wrapping a great saphenous vein patch reinforcement circumferentially around the damaged biological vascular conduit and filling the infected wound with a rectus abdominis myocutaneous muscle flap transposition. The aim of this report is to illustrate this novel, to our knowledge, 'perivascular venous banding' technique and to evaluate the prospective of future testing of this surgical procedure. Starting from this singular case, we will also review the role of the rotational muscle flaps in the conservative management of major vascular graft infections.

Abstract No. 410: The use of the patent ductus venosus as an access for portal vascular interventions in children

The ductus venosus, a fetal communication between the portal and systemic venous circulations, spontaneously closes early in the neonatal period. The persistence of the ductus venosus is rare and can be primary (congenital) or secondary to abnormal portal hemodynamics. Vascular anomalies of the portal vein can be associated with serious clinical presentation and pose technical challenges at interventions. In such patients, the patent ductus venosus provides a safe and valuable alternative access for endovascular treatment. 4 children (age: 2 months 6 years) underwent interventional treatment of vascular anomalies of the portal vein using the patent ductus venosus as a vascular conduit to the portal vein via a transjugular approach. Two patients had arterioportal fistulae; one had a large portosystemic shunt with severe gastrointestinal bleeding and one congenital hemangioma with heart and liver failure. Mesenteric arteriography was initially performed followed by transjugular access of the patent ductus venosus and embolization of the portal anomaly. All the procedures were technically successful using the patent ductus venosus. In patient # 1 with a fistula between the inferior phrenic artery and portal vein, the shunt was embolized with coils. Patient # 2 had a complex arterioportal shunt with a giant portal aneurysm was embolized with an Amplatzer septal occluder and coils. The portosystemic shunt in patient # 3 was closed using an Amplatzer vascular plug. Embolization of the portal feeding tributaries to the liver hemangioma in patient # 4 was done with coils. The procedures were technically successful in the four children without complications. The arterioportal fistula (patient # 1) and the portosystemic shunt (patient # 3) were completely obliterated and clinically successfully. Though technically successful, the response to embolization in patients # 2 and 3 (complex arterioportal fistula and congenital liver hemangioma, respectively) was partial; largely related to other serious comorbidity. Patent ductus venosus provides an invaluable safe access for endovascular portal venous interventions in children.

Invited commentary

The poor availability of usable autogenous conduit for vascular bypass grafting remains a significant clinical problem. Less than half of all patients requiring lower extremity bypass grafting can be reconstructed using appropriately sized, disease-free, single-segment greater saphenous vein. This has long prompted the search for an operative strategy wherein, instead of harvesting autologous veins or implanting prosthetics, useable vascular conduits can be “grown” in a laboratory in the days prior to elective revascularization. Such “tissue-engineered” conduits are the subject of the study conducted by Quint et al and reported herein. In a series of bench top and animal experiments, human tissue engineered vessels (hTEV) were grown using a process employing human aortic smooth muscle cells (SMCs), biodegradable scaffolds, biomimetic perfusion, and decellularization. After creation in vitro, the hTEVs were implanted as aortic interposition grafts in nude rats and found to have acceptable 6-week patency (83%) without evidence of aneurysm formation or rupture. When explanted and examined, the decellularized hTEVs were found to have recruited a confluent endothelium and coaxial subendothelial SMCs. This is a remarkable and ingenious scientific feat. Of course, a myriad of issues must be addressed prior to consideration of clinical application of hTEVs. First and foremost is the certain immunogenicity of conduits created using heterologous human tissue, immunogenicity that was not observed in this experiment given the use of nude hosts. Decellularization could be expected to attenuate immunologic responses to the level of tolerance, perhaps, but even low levels of chronic antigenicity may negatively affect patency. The logistical practicalities of the approach also loom large, as the consistent creation of acceptable conduits is obviously a highly specialized and technical endeavor. Do we really envision a time when personalized surgical “spare parts” are routinely available in clinical practice? It seems more likely that conduits such as these will be created in a central, commercial laboratory and distributed to hospitals in a similar fashion as currently available medical devices. Thus, the “personal” nature of such devices will likely be limited. These shortcomings notwithstanding, Quint and colleagues offer a provocative and inventive solution to the ubiquitous problem of small-diameter, long-segment vascular conduit availability. It is hoped that this group will refine their process and technique, extend these initial experimental observations, and swiftly advance to the clinical phase of development. Allogeneic human tissue-engineered blood vesselJournal of Vascular SurgeryVol. 55Issue 3PreviewArterial bypass graft implantation remains the primary therapy for patients with advanced cardiovascular disease; however, there is no available synthetic small-diameter vascular graft. Full-Text PDF Open Archive

Arteriovenous Loop Grafts for Free Tissue Transfer

Arteriovenous (AV) loop grafts are a type of vascular conduit that can be used to support free tissue transfer. Wounds of various etiologies may require free tissue transfer, and the AV loop graft is a useful adjunct when adjacent blood supply is inadequate. Here we present 2 cases and review the technique and published literature.

MORHOLOGICAL AND FUNCTIONAL ASPECTS OF THE APPLICATION OF FEMORAL VEINS FOR AORTOILIAC RECONSTRUCTION IN EXPERIMENT

The aim of the study. To study the functional adequacy of different vascular conduits. Material and methods. The morphological and functional qualities of femoral vein in comparison with those of superficial vein and artificial prosthesis in 12 pedigreeless male dogs weighted 15,3 ± 3,7 kg have been studied. All the dogs underwent ilio-femoral bypass with combined conduit, sewn from the fragments of femoral vein, superficial vein and polytetrafluorinethylene vascular prosthesis. The specimens were obtained in the interval of 3, 6, 9 and 12 months. Mann-Whitney`s U-criterion, a non-parametric method for comparison of two independent samples was applied to compare the quantities that are not subject to Gauss` distribution. Results and discussion. The apex of morphological-functional rebuilding of veins, caused by their involvement in arterial flow, seems to appear in the interval from 3 to 6 months since the implantation. The changes of femoral vein occur earlier then those of subcutaneous vein. The dystrophic signs are less expressed in femoral vein. The morphological-functional properties of femoral vein differ from those of superficial vein. A peak of regenerative processes on the surface of the artificial vascular prosthesis falls on the term of 6 months. The later termed involutive processes prevail over the regenerative processes.

Superior Vena Cava and Innominate Vein Reconstruction in Thoracic Malignancies: Double-Vein Reconstruction

Extensive major venous resection and reconstruction with prosthetic vascular conduits are feasible with very good shortand long-term results. Okereke et al1 described the use of an externally stented polytetrafluoroethylene (PTFE) conduit for bypass of the superior vena cava (SVC) with 90% patency at a mean of 24 months. Sekine et al2 expanded on the traditional method of reconstruction by using direct independent grafts between the left and right innominate veins (IV) and the right atrium. We describe our technique for independent reconstruction of the left and right innominate venous systems by using ringed PTFE prosthetic vascular grafts.

Widening of xylem conduits in a conifer tree depends on the longer time of cell expansion downwards along the stem.

The diameter of vascular conduits increases towards the stem base. It has been suggested that this profile is an efficient anatomical feature for reducing the hydraulic resistance when trees grow taller. However, the mechanism that controls the cell diameter along the plant is not fully understood. The timing of cell differentiation along the stem was investigated. Cambial activity and cell differentiation were investigated in a Picea abies tree (11.5 m in height) collecting microsamples at nine different heights (from 1 to 9 m) along the stem with a 4 d time interval. Wood sections (8–12 μm thick) were stained and observed under a light microscope with polarized light to differentiate the developing xylem cells. Cell wall lignification was detected using cresyl violet acetate. The first enlarging cells appeared almost simultaneously along the tree axis indicating that cambium activation is not height-dependent. A significant increase in the duration of the cell expansion phase was observed towards the tree base: at 9 m from the ground, xylem cells expanded for 7 d, at 6 m for 14 d, and at 3 m for 19 d. The duration of the expansion phase is positively correlated with the lumen area of the tracheids (r2=0.68, P < 0.01) at the same height. By contrast, thickness of the cell wall of the earlywood did not show any trend with height. The lumen area of the conduits down the stem appeared linearly dependent on time during which differentiating cells remained in the expansion phase. However, the inductive signal of such long-distance patterned differentiation remains to be identified.

Evolution of anterior segment reconstruction after live donor adult liver transplantation: a single‐center experience

Controversy exists regarding the best method for venous outflow reconstruction after live donor liver transplantation using right lobe grafts. Some authors advocate routine inclusion of the middle hepatic vein with the graft, whereas others favor a more selective approach. In this report, we examine the evolution of our decision making and technique of selective anterior venous segment reconstruction during live donor adult liver transplantation performed in 226 recipients. We have developed a simplified back-bench procedure using sequential-composite anastomosis using various vascular conduits with syndactylization to the right hepatic vein creating a single large-outflow anastomosis in the recipient. Conduits used include iliac artery or vein allograft, recanalized umbilical vein, cryopreserved iliac artery allograft, and 6-mm synthetic expanded polytetrafluoroethylene vascular graft. This technique can be performed quickly, safely, and under cold storage conditions and results in excellent outcome while minimizing donor risk.

Hierarchically Designed Electrospun Tubular Scaffolds for Cardiovascular Applications

Hierarchically designed tubular scaffolds with bi-layer and multi-layer structures are expected to mimic native vessels in its structural geometry. A new approach for the fabrication of hierarchically designed tubular scaffold with suitable morphology was introduced through electrospinning technique. Among these scaffolds, bi-layer scaffold had a single inner and outer layer whereas multilayer scaffold had more number of inner layers. The inner layer/layers of the scaffolds were made up of aligned poly (lactic acid) (PLA) fibers for EC adhesion where as outer layers were composed of random fibers of poly (caprolactone) (PCL) and PLA providing larger pores for SMC penetration. The fabricated scaffolds were characterized by FTIR spectroscopy and Differential Thermal Analysis (DTA) and examined by evaluating cellular interactions. Human Umbilical Vein Endothelial Cells (HUVECs) seeded on aligned PLA fibers showed enhanced cellular orientation and cytoskeletal organization. In addition, the PCL-PLA composite random fibers supported SMC adhesion and proliferation sufficiently. The functionality of the endothelial cells grown on the PLA-aligned scaffold was also found to be satisfactory. Lining the constructs with a luminal monolayer of well-organized ECs along with homogenously distributed SMCs surrounding them might result in vascular conduits suitable for in vivo applications. Since this hierarchically designed tubular scaffold closely mimics the morphology of native vessel, this could be a better candidate for vascular tissue engineering.

Aligned electrospun scaffolds and elastogenic factors for vascular cell-mediated elastic matrix assembly

Strategies to enhance the production of organized elastic matrix by smooth muscle cells (SMCs) are critical in engineering functional vascular conduits. Therefore, the goal of this study was to determine the effect of different surfaces, i.e. random and aligned electrospun poly(ε-caprolactone) meshes and two-dimensional (2D) controls, and exogenous elastogenic factors on the cultured rat aortic SMC phenotype and production of extracellular matrix. This study demonstrated that aligned electrospun fibres guide cell alignment, induce a more elongated cell morphology and promote a more synthetic phenotype. Importantly, these cells produced greater amounts of elastin-rich matrix per cell on the electrospun scaffolds. In addition, exogenous elastogenic factors severely limited rat aortic smooth muscle cells (RASMCs) proliferation and promoted a more synthetic SMC phenotype on electrospun meshes, but they had less effect on 2D controls. Finally, the elastogenic factors induced the SMCs to generate more matrix collagen and elastin on a per cell basis. Together, these results demonstrate the elastogenic benefits of electrospun meshes.

The Artery of Bernasconi and Cassinari: A Morphometric Study for Superselective Catheterization

The artery of Bernasconi and Cassinari is an important infraclinoid branch of the internal cerebral artery. It is of neuroendovascular relevance in view of its supply to complex lesions such as meningiomas and arteriovenous malformations in the tentorial and falcotentorial regions. The present microanatomic study attempts a morphometric elucidation of this slender but important branch of the meningohypophyseal trunk. The origin, course, dimensions, and related variations of the tentorial artery were studied in 10 formalin-fixed human cadaveric sides. The tentorial artery originated from the meningohypophyseal trunk in all but 1 specimen, in which it arose directly from the intracavernous internal carotid artery. In 80% of specimens, it took origin as a single branch; as a bifurcation and trifurcation in 1 each. It was usually the terminal branch of the meningohypophyseal trunk (in 90%). In all, 5 distinct microvascular patterns were noted. The mean diameter of this artery was 0.7 mm (range, 0.3-0.8 mm; SD, ± 0.1 mm). The mean length was 15.4 mm (range, 9-23 mm; SD, ± 4.4 mm). Its mean distance from the origin of the meningohypophyseal trunk was 1.7 mm (range, 1.3-2.3 mm; SD, ± 0.4 mm). The mean distance from the free edge of the tentorium was 3.7 mm (range, 3-5 mm; SD, ± 0.7 mm). The artery of Bernasconi and Cassinari is an important vascular conduit to myriad neoplasms and vascular malformations in the vicinity of the tentorium cerebelli. In this era of advanced microneurosurgical techniques and superselective endovascular interventions, morphometric knowledge of this artery is important for precise and safe management of these lesions.