Popliteal artery aneurysm in a 14-year-old boy with tuberous sclerosis complex.

Tuberous sclerosis complex (TSC) is rarely associated with aneurysms. We have described a patient with a popliteal artery aneurysm that was associated with TSC and occlusion of the right posterior tibial artery. The patient underwent aneurysm resection and vein graft replacement, with an uneventful postoperative course and no recurrence at 11 months of follow-up. Patients with TSC could have aneurysms in areas that will not be recognized on abdominal imaging. Physical examination of the lower extremities should be performed owing to the possibility of a popliteal artery aneurysm, and imaging studies should be performed if an aneurysm is suspected.

Endovascular coil embolization for an anomalous splenic artery aneurysm with a splenomesenteric trunk.

We present a case of a splenic artery (SA) aneurysm (SAA) that had arisen abnormally from the superior mesenteric artery in a 63-year-old man who underwent successful endovascular treatment. Although SAAs characterized by this anatomic abnormality are rare, in all 46 reported cases, the SAAs were located at the root of the SA and had originated abnormally from the superior mesenteric artery. This location is different from that of orthotopic SAAs, which are mostly located in the distal third of the SA. The differences in hemodynamics due to the anatomic abnormalities might play an important role in the formation of the anomalous SAAs.

Volumetric computed tomography analysis for gastroduodenal and pancreaticoduodenal artery aneurysm formation: A retrospective single-center study.

ABSTRACT: Gastroduodenal artery aneurysms (GDAA) and pancreaticoduodenal artery aneurysms (PDAA) are rare, have high rupture risks, and are located in the arcade between the celiac artery and the superior mesenteric artery. Pancreaticoduodenal artery aneurysms are associated with celiac artery stenosis, and it is hypothesized that these celiac lesions might contribute to the formation of aneurysms. In contrast, a few studies have reported an association between a gastroduodenal artery aneurysm and celiac lesions. This study aimed to investigate the potential differences between patients with gastroduodenal and pancreaticoduodenal artery aneurysms and better understand their pathogenesis.We selected patients with GDAA and PDAA who were admitted to our department between January 2010 and December 2020. Aortic wall volume, aortic wall calcification, and pancreaticoduodenal arcade volume of computed tomography images were calculated semi-manually using Horos 3.3.5.Eight GDAAs and 11 PDAAs were analyzed. Celiac lesions were found in all PDAA patients, with none in GDAA cases. Volumetry demonstrated that aortic wall volume and calcification were more prominent in the GDAA group than in the PDAA group (P = .026 and P = .049, respectively). The pancreaticoduodenal arcade volume was larger in the PDAA group (P = .002).In our study, celiac artery lesions were strongly correlated with PDAA. The volume of the pancreaticoduodenal arcade was larger in the PDAA group, and aortic wall volume and calcification were larger in the GDAA group.

Motion analysis of suturing technique with Leap Motion ControllerTM. Proof-of-concept.

PURPOSE: Leap Motion Controller is a device that can capture hand gestures and reproduce these as data comprising several parametric elements. We analyzed surgical suture motion using this device and investigated the optical methodology for clinical applications. METHODS: We recruited medical students and residents (novice group) and vascular surgeons (specialist group). The operators applied sutures once on a prosthetic graft, and the captured motion was analyzed. RESULTS: Ten novices, who each received procedural instruction for at least 2 h, and 10 specialists were recruited. The hand gesture consisted of four elements (roll, pitch, yaw, and wrist angle). Since "roll" was the only element in this simple suture movement that showed some difference between the two groups, we analyzed three parameters: (1) the suturing time, (2) the difference in the degree between two piercing points, and (3) slope of the roll. We found that the specialist group demonstrated significantly shorter suturing times and a larger degree of the slope. CONCLUSION: Leap Motion Controller analysis with the roll revealed that the novices could use the roll motion after only 2 h of instruction; however, the suturing speed and smoothness were secondary to those of the specialists.

Ten-Hour Simulation Training Improved the Suturing Performance of Medical Students.

PURPOSE: We evaluated the effectiveness of an original simulation training system in improving the suturing performance of medical students using a previously developed web application for scoring suturing performance. METHODS: Medical students were recruited for this study and trained on vascular graft anastomosis. Prosthetic grafts were anastomosed and evaluated after orientation, and after 1 hr and 10 hr after training. Vascular surgeons were recruited as controls. Using a previously developed web application, suturing performance was evaluated on the basis of procedural time, coefficient of variation of bite (length of a stitch across the graft), coefficient of variation of pitch (interval between stitches), and skewness (symmetry of the angles between stitches). RESULTS: Forty-eight medical students and 10 vascular surgeons were recruited. After 1 hr of training, only the students' procedural time improved. After 10 hr of training, all scores improved compared with those in the first trial, and all students' scores except procedural time were statistically similar to those of the vascular surgeons. CONCLUSIONS: Ten-hour training improved all factors, including bite, pitch, skewness, and time. Our simple and inexpensive training system and web application for calculating anastomosis scores can be a useful open educational resource.

Drug-Coated Balloon versus Plain Balloon Angioplasty in the Treatment of Infrainguinal Vein Bypass Stenosis: A Systematic Review and Meta-Analysis.

The optimal endovascular therapy for vein graft stenosis (VGS) following infrainguinal arterial bypass is yet to be established. Drug-coated balloons (DCB) have rapidly improved the inferior patency outcomes of angioplasty using a conventional plain balloon (PB). This study compares the efficacy of DCBs and PBs for the treatment of infrainguinal VGS. This systematic review and meta-analysis was performed according to the PRISMA statement. Multiple electronic searches were conducted in consultation with a health science librarian in September 2022. Studies describing the comparative outcomes of angioplasty using DCBs and PBs in the treatment of infrainguinal VGS were eligible. Datasets from one randomized controlled trial and two cohort studies with a total of 179 patients were identified. The results indicated no significant difference in target lesion revascularization between DCBs and PBs (OR, 0.64; 95% CI, 0.32-1.28; p = 0.21), with no significant heterogeneity between studies. Additionally, differences in primary patency, assisted primary patency, secondary patency, and graft occlusion were not significant. Subgroup analysis showed similar effects for different DCB devices. In conclusion, DCBs showed no significant benefit in the treatment of VGS compared to PBs. Given the small population size of this meta-analysis, future trials with a larger population are desired.

A Radiation-Crosslinked Gelatin Hydrogel That Promotes Tissue Incorporation of an Expanded Polytetrafluoroethylene Vascular Graft in Rats.

A prosthetic vascular graft that induces perigraft tissue incorporation may effectively prevent serious sequelae such as seroma formation and infection. Radiation-crosslinked gelatin hydrogel (RXgel) mimics the chemical and physical properties of the in vivo extracellular matrix and may facilitate wound healing by promoting tissue organization. Fibroblasts cultured on RXgel actively migrated into the gel for up to 7 days. RXgels of three different degrees of hardness (Rx[10], soft; Rx[15], middle; Rx[20], hard) were prepared, and small disc-like samples of RXgels were implanted into rats. In vitro and in vivo results indicated that Rx[10] was too soft to coat vascular grafts. Thus, expanded polytetrafluoroethylene (ePTFE) vascular grafts coated with RXgel were developed using Rx[15] and Rx[20] gels, and ring-shaped slices of the graft were implanted into rats. Alpha-smooth muscle actin (αSMA) and type III collagen (Col-III) levels were detected by immunohistochemistry. Immunohistochemical staining for αSMA and Col-III demonstrated that RXgel-coated vascular grafts induced more granulation tissue than non-coated grafts on days 14 and 28 after implantation. RXgel-coated ePTFE vascular grafts may provide a solution for patients by reducing poor perigraft tissue incorporation.

Carotid Stump Pressure and Contralateral Internal Carotid Stenosis Ratio During Carotid Endarterectomies: 1D-0D Hemodynamic Simulation of Cerebral Perfusion.

Objective: We selectively place carotid shunting when ipsilateral mean stump pressure is less than 40 mmHg during carotid endarterectomy (CEA). This study aimed to assess the validity of our selective shunting criterion by 1D-0D hemodynamic simulation technology. Materials and Methods: We retrospectively reviewed 88 patients (95 cases) of CEA and divided them into two groups based on the degree of contralateral internal carotid artery (ICA) stenosis ratio, which was determined as severe when the peak systolic velocity ratio of the ICA to the common carotid artery was ≥4 by carotid duplex ultrasonography. Patients with severe stenosis or occlusion in contralateral ICA were classified as hypoperfusion group, and those without such contralateral ICA obstruction were classified as control group. Results: Perioperatively, the mean carotid stump pressures were 33 mmHg in hypoperfusion group and 46 mmHg in the control group (P=0.006). We simulated changes in carotid stump pressure according to the changes in the contralateral ICA stenosis ratio. 1D-0D simulation indicated a sharp decline in carotid stump pressure when the contralateral stenosis ratio was >50%, while peripheral pressure of the middle cerebral arteries declined sharply at a ≥70% contralateral stenosis ratio. At this ratio, the direction of the ipsilateral cerebral arterial flow became inverted, the carotid stump pressure became dependent on the basilar artery circulation, and the ipsilateral middle cerebral artery became hypoperfused. Conclusion: Our clinical and computer-simulated results confirmed the validation of our carotid shunting criterion and suggested that contralateral ICA stenosis ratio over 70% is a safe indication of selective shunting during CEA.

A comparison of subjective clinical and objective judgement of abdominal aortic aneurysm morphology.

BACKGROUND: We compared the subjective, clinical judgement of "saccular" morphology with the objective judgement of mechanical structural analysis. METHODS: Using structural analysis with the finite element method, we previously created a simple model of abdominal aortic aneurysm (AAA) that visualized the distribution of the maximum principal stress (MPS) in the aortic wall and identified the area of prominent stress. AAA "saccular" morphology was determined according to the area showing MPS>0.03 MPa. AAAs with low aspect ratio (horizontally long AAA sac) and small fillet radius were defined as "saccular." Twelve vascular surgeons were recruited. First, they judged the AAA as saccular or fusiform with 3-dimensional images at their clinical impression (subjective "eyeball" judgement). Second, they applied the deformable figure tools on the simple AAA-shaped sagittal view in the application model for 30 AAA cases. From the data of the tools applied, the mechanical structural analysis was performed semi-automatically and the morphology was judged with the objective "simple application." RESULTS: The structural analysis revealed that only one case was judged as saccular by 11 out of 12 surgeons and the other 29 AAAs were judged as fusiform by two-thirds or more of the surgeons. In contrast, 5 cases were subjectively judged as saccular by eight and more of the surgeons. CONCLUSIONS: The clinical judgement of AAA saccular morphology by the vascular surgeons was different from the judgement derived from the mechanical structural analysis using the application model. The saccular morphology may be theoretically rare in AAAs.

High aneurysm wall enhancement values are associated with late sac shrinkage after endovascular repair of abdominal aortic aneurysms.

ABSTRACT: To analyze the correlation between aneurysm wall enhancement (AWE) values and early and late sac shrinkage after endovascular aneurysm repair (EVAR).We retrospectively analyzed 28 patients who underwent EVAR for abdominal aortic aneurysms (AAA) using a bifurcated main body stent graft. The value of AWE in the slice of the maximum AAA diameter was measured using a volumetric analysis of computed tomography images. Sac measurements before EVAR and more than 10 months after EVAR were compared, and the maximum sac shrinkage rate was calculated.The AWE value immediately after (4 to 7 days) EVAR correlated positively with the sac shrinkage rate (R2 = 0.0139). The AWE value at 6 months after EVAR was also strongly correlated with the sac shrinkage rate (R2 = 0.4982).Higher AWE values at 6 months after EVAR were strongly associated with the sac volume shrinkage rate. High AWE values may be a predictive factor for sac shrinkage and may aid in the selection of the appropriate clinical strategy after EVAR.

Hydrogel-based 3D bioprints repair rat small intestine injuries and integrate into native intestinal tissue.

3D Printing has become a mainstay of industry, with several applications in the medical field. One area that could benefit from 3D printing is intestinal failure due to injury or genetic malformations. We bioprinted cylindrical tubes from rat vascular cells that were sized to form biopatches. 2 mm enterotomies were made in the small intestine of male Sprague-Dawley rats, and sealed with biopatches. These intestinal segments were connected to an ex vivo perfusion device that provided independent extraluminal and intraluminal perfusion. The fluorescence signal of fluorescein isothiocyanate (FITC)-inulin in the intraluminal perfusate, a non-absorbable fluorescent marker of intestinal integrity, was measured every 15 min over 90 min, and used to assess the integrity of the segments under both continuous perfusion and alternate-flow perfusion. Enterotomies were made an inch away from the ileocecal junction in male Wistar rats and sealed with biopatches. The animals were monitored daily and euthanized at post-operative days 7, 14, 21, and 30. Blinded histopathological analysis was conducted to compare the patch segments to native intestine. Biopatch-sealed intestinal segments withstood both continuous and pulsatile flow rates without leakage of FITC-inulin above the control baseline. 21 of 26 animals survived with normal activity, weight gain, and stool output. Histopathology of the explanted segments showed progressive villi and crypt formation over the enterotomies, with complete restoration of the epithelium by 30 days. This study presents a novel application of 3D bioprinting to develop a universal repair patch that can seal lesions in vivo, and fully integrate into the native intestine.

A case of endovascular therapy for treating idiopathic arterial deteriorations of unknown etiology.

INTRODUCTION: Peripheral artery pseudoaneurysm as a consequence of arterial deterioration is relatively rare in young populations, who typically lack an atherosclerotic background. Such pseudoaneurysms are known to pose a risk of rupture, which is correlated with high mortality and morbidity rates. Pseudoaneurysms are more prone to rupture than true aneurysms are, as their vessel walls tear more easily. We present the case of a 50-year-old patient who had multiple arterial deteriorations. CASE PRESENTATION: The patient experienced backache, and computed tomography revealed a tear of the right renal artery, and a pseudoaneurysm of the left internal iliac artery. He had a history of graft replacement for the right superficial artery pseudoaneurysm, which had been occluded. Although various tests were performed for differential diagnosis, the etiology was unidentified. Considering the suspected vascular fragility and failure of previous direct intervention, these 2 lesions were treated by placing endografts simultaneously. DISCUSSION: We investigated various diseases causing vascular fragility in the reported case, such as vascular Behçet disease, vascular Ehlers-Danlos syndrome, fibromuscular dysplasia, and segmental arterial mediolysis. However, these were all excluded and the etiology remains unclear. Progress in endovascular techniques enables the use of minimally invasive treatment in patients with vascular fragility. CONCLUSION: When vascular fragility may exist, endovascular treatment is a desirable option, as it can be performed repetitively and is less invasive.

Altered hemodynamics during arteriovenous fistula remodeling leads to reduced fistula patency in female mice.

OBJECTIVE: The arteriovenous fistula (AVF) is the preferred method of dialysis access because of its proven superior long-term outcomes.However, women havelower rates of AVF patency andutilizationthan men.We used a novel mouseAVF model that recapitulates human AVF maturation to determine whether there are differences in AVF patency in female and male mice. METHODS: Aortocaval fistulas were created in female and male C57BL/6 mice (9-10 weeks). At days 0, 3, 7, and 21, infrarenal inferior vena cava (IVC) and aortic diameters and flow velocity were monitored by Doppler ultrasound and used to calculate the vessel diameter, blood flow, and shear stress. AVF were harvested, and expression of proteins was examined by proteomic analysis and immunofluorescence and of messenger RNA by quantitative polymerase chain reaction analysis. RESULTS: At baseline, female mice weighed less and had lower IVC velocity and smaller magnitudes of shear stress, but there was no significant difference in IVC diameter and thickness. After AVF creation, both female and male mice had similar IVC dilation and thickening with no significant differences in IVC wall thickness at day 21. However, female mice had diminished AVF patency by day 42 (25.7% vs 64.3%; P = .039). During fistula remodeling, female mice had lower IVC mean velocity and shear stress magnitude and increased spectral broadening (days 0-21). Messenger RNA and protein expression of Krüppel-like factor 2, endothelial nitric oxide synthase, and vascular cell adhesion molecule 1 was similar at baseline in female and male mice but increased in the AVF only in male mice but not in female mice (day 21). Proteomic analysis of female and male mice detected 56 proteins expressed at significantly higher levels in the IVC of female mice and 67 proteins expressed at significantly higher levels in the IVC of male mice (day 7); function-specific analysis showed that the IVC of male mice overexpressed proteins that belong to pathways implicated in the regulation of vascular function, thrombosis, response to flow, and vascular remodeling. CONCLUSIONS: AVF in female mice have diminished patency, preceded by lower velocity, reduced magnitudes of shear stress, and less laminar flow during remodeling. There is also sex-specific differential expression of proteins involved in thrombosis, response to laminar flow, inflammation, and proliferation. These findings suggest that hemodynamic changes during fistula maturation may play an important role underlying the diminished rates of AVF utilization in women. CLINICAL RELEVANCE: Women have lower rates of arteriovenous fistula (AVF) utilization than men. Using a mouse AVF model that recapitulates human AVF maturation, we show that female mice have similar AVF remodeling but diminished patency. AVF remodeling in female mice is associated with reduced shear stress and laminar flow; lack of increased transcription and translation of several anti-inflammatory, antiproliferative, and laminar flow response proteins (endothelial nitric oxide synthase, Krüppel-like factor 2, and vascular cell adhesion molecule 1); and different patterns of expression of pathways that regulate thrombosis and venous remodeling. Identifying downstream targets involved in these mechanisms may improve AVF outcomes in female patients.

Author Correction: Inhibition of the Akt1-mTORC1 Axis Alters Venous Remodeling to Improve Arteriovenous Fistula Patency.

An amendment to this paper has been published and can be accessed via a link at the top of the paper.

TGFß (Transforming Growth Factor-Beta)-Activated Kinase 1 Regulates Arteriovenous Fistula Maturation.

OBJECTIVE: Arteriovenous fistulae (AVF) are the optimal conduit for hemodialysis access but have high rates of primary maturation failure. Successful AVF maturation requires wall thickening with deposition of ECM (extracellular matrix) including collagen and fibronectin, as well as lumen dilation. TAK1 (TGFß [transforming growth factor-beta]-activated kinase 1) is a mediator of noncanonical TGFß signaling and plays crucial roles in regulation of ECM production and deposition; therefore, we hypothesized that TAK1 regulates wall thickening and lumen dilation during AVF maturation. Approach and Results: In both human and mouse AVF, immunoreactivity of TAK1, JNK (c-Jun N-terminal kinase), p38, collagen 1, and fibronectin was significantly increased compared with control veins. Manipulation of TAK1 in vivo altered AVF wall thickening and luminal diameter; reduced TAK1 function was associated with reduced thickness and smaller diameter, whereas activation of TAK1 function was associated with increased thickness and larger diameter. Arterial magnitudes of laminar shear stress (20 dyne/cm2) activated noncanonical TGFß signaling including TAK1 phosphorylation in mouse endothelial cells. CONCLUSIONS: TAK1 is increased in AVF, and TAK1 manipulation in a mouse AVF model regulates AVF thickness and diameter. Targeting noncanonical TGFß signaling such as TAK1 might be a novel therapeutic approach to improve AVF maturation.

Development of a Web Application That Evaluates Suture Performance in Off-the-Job Training.

Objective: To create a web application that can evaluate suture performance and assess its quality. Material and Methods: We developed the web application using a few cloud computing systems, servers, database, and computing languages. We used 20 anastomosed graft samples for optimizing the application. The images of the anastomosed grafts were captured two-dimensionally. Five vascular surgeons utilized the application to compute the objective score and rank the score of the anastomoses subjectively. Results: Steps for using the application include uploading a two-dimensional image of sutures, tracing the stitch line manually, and pushing the button to have the score displayed. After using this system for more than 1,000 times without server issues or failures, we confirmed its stability and easy accessibility. The system calculated the score within several seconds. The score of the three factors (bite, pitch, and skewness of angle) ranged from 0.25 to 0.76. The error range of the application was acceptable. The interclass correlation coefficient (ICC (2,1)) of the three factors was 0.92. Conclusion: The quality of the application was acceptable considering the low range of interoperator variations in the scores.

Venous Mechanical Properties After Arteriovenous Fistulae in Mice.

BACKGROUND: An arteriovenous fistula (AVF) exposes the outflow vein to arterial magnitudes and frequencies of blood pressure and flow, triggering molecular pathways that result in venous remodeling and AVF maturation. It is unknown, however, how venous remodeling, that is lumen dilation and wall thickening, affects venous mechanical properties. We hypothesized that a fistula is more compliant compared with a vein because of altered contributions of collagen and elastin to the mechanical properties. METHODS: Ephb4+/- and littermate wild-type (WT) male mice were treated with sham surgery or needle puncture to create an abdominal aortocaval fistulae. The thoracic inferior vena cava was harvested 3 wk postoperatively for mechanical testing and histological analyses of collagen and elastin. RESULTS: Mechanical testing of the thoracic inferior vena cava from Ephb4+/- and WT mice showed increased distensibility and increased compliance of downstream veins after AVF compared with sham. Although Ephb4+/- veins were thicker than WT veins at the baseline, after AVF, both Ephb4+/- and WT veins showed similar wall thickness as well as similar collagen and elastin area fractions, but increased collagen undulation compared with sham. CONCLUSIONS: Fistula-induced remodeling of the outflow vein results in circumferentially increased distensibility and compliance, likely due to post-translational modifications to collagen.

A mouse model of stenosis distal to an arteriovenous fistula recapitulates human central venous stenosis.

OBJECTIVE: Central venous stenosis (CVS) is a major cause of arteriovenous fistula (AVF) failure. However, central veins are relatively inaccessible to study with conventional Doppler ultrasound methods. To understand mechanisms underlying AVF failure owing to CVS, an animal model was established that creates a stenosis distal to an AVF. We hypothesized that this mouse model will show comparable morphology and physiology to human CVS. METHODS: An aortocaval fistula was created between the distal aorta and inferior vena cava (IVC); a stenosis was then created distal to the fistula by partial IVC ligation. Sham-operated animals, AVF without venous stenosis, and venous stenosis without AVF were used as controls. Physiologic properties of the IVC, both upstream and downstream of the stenosis, or the corresponding sites in models without stenosis, were assessed with ultrasound examination on days 0 to 21. The spectral broadening index was measured to assess the degree of disturbed shear stress. The IVC was harvested at day 21 and specimens were analyzed with immunofluorescence. RESULTS: The IVC diameter of mice with an AVF and stenosis showed increased upstream (P = .013), but decreased downstream diameter (P = .001) compared with mice with an AVF but without a stenosis, at all postoperative times (days 3-21). IVC wall thickness increased in mice with an AVF, compared with IVC without an AVF (upstream of stenosis: 13.9 µm vs 11.0 µm vs 4.5 µm vs 3.9 µm; P = .020; downstream of stenosis: 6.0 µm vs 6.6 µm vs µm 4.5 µm vs 3.8 µm; P = .002; AVF with stenosis, AVF, stenosis, sham, respectively). AVF patency significantly decreased in mice with an AVF and stenosis by day 21 (50% vs 90%; P = .048). The IVC of mice with AVF and stenosis showed a venous waveform with pulsatility as well as enhanced velocity at and downstream of the stenosis; similar waveforms were observed in a human case of CVS. Downstream to the stenosis, the spectral broadening index was significantly higher compared with mice with AVF alone (1.06 vs 0.78; P = .011; day 21), and there was a trend towards less immunoreactivity of both Krüppel-like factor 2 and phosphorylated-endothelial nitric oxide synthase compared with mice with an AVF alone. CONCLUSIONS: Partial IVC ligation distal to a mouse aortocaval fistula alters the fistula diameter and wall thickness, decreases patency, and increases distal disturbed flow compared with fistulae without a distal stenosis. Our mouse model of stenosis distal to an AVF may be a faithful representation of human CVS that shows similar morphology and physiology, including disturbed shear stress.

Egg-shell like Calcification as a Protective Factor for Splenic Artery Aneurysm Dilatation.

BACKGROUND: The purpose of this study was to evaluate the factors associated with asymptomatic splenic artery aneurysm (SAA) dilatation. METHODS: Among patients with SAA admitted to our department from 2001 to 2018, 70 lesions in 59 patients were selected and analyzed retrospectively. There were no cases of rupture or pregnancy in the follow-up period. We defined egg-shell appearance as SAA with >75% calcification of the outer shell. We measured the dilatation rate (mm/year) and evaluated the comorbidity and anatomical factors using univariate and multiple linear regression models. Post-hoc multiple linear regression models were fitted to evaluate the possible interactions. RESULTS: The mean age was 61.4 years (range 35-85 years), and the initial aneurysm diameter was 15.1 mm (range 3-47 mm). The mean dilatation rate was 0.26 mm/year (range 0-3.2 mm/year) during the follow-up period (average 4.6 years). Univariate analysis revealed that, portal hypertension (PHT) (P = 0.0003), egg-shell appearance (P = 0.007), and aneurysm diameter > 20 mm (P = 0.05) were significantly associated with the dilatation rate. Multivariate analysis revealed that egg-shell appearance was found to be an independent inverse risk factor of dilatation rate (P = 0.006). The multivariate analysis, including interaction terms, revealed a stronger effect of PHT and diameter >20 mm in cases with no egg-shell appearance (P = 0.08 and P = 0.05 for interactions, respectively). CONCLUSIONS: The egg-shell appearance of SAA was an independent inverse risk factor affecting the SAA dilatation rate. The dilatation rates in the case of PHT and diameter >20 mm were restricted in the presence of the egg-shell appearance.

Reduced patency in left-sided arteriovenous grafts in a porcine model.

OBJECTIVE: The porcine arteriovenous graft model is commonly used to study hemodialysis vascular access failure, with most studies using a bilateral, paired-site approach in either the neck or femoral vessels. In humans, left- and right-sided central veins have different anatomy and diameters, and left-sided central vein catheters have worse outcomes. We assessed the effect of laterality on arteriovenous prosthetic graft patency and hypothesized that left-sided carotid-jugular arteriovenous prosthetic grafts have reduced patency in the porcine model. METHODS: Arteriovenous polytetrafluoroethylene grafts were placed ipsilaterally or bilaterally in 10 Yorkshire male pigs from the common carotid artery to the internal jugular vein. Ultrasound measurements of blood flow velocities and diameters were assessed before graft placement. Animals were sacrificed at 1 week, 2 weeks, or 3 weeks. Patency was determined clinically; grafts and perianastomotic vessels were excised and analyzed with histology and immunostaining. RESULTS: At baseline, left- and right-sided veins and arteries had similar blood flow velocities. Although internal jugular veins had similar diameters at baseline, left-sided carotid arteries had 11% smaller outer diameters (P = .0354). There were 10 left-sided and 8 right-sided polytetrafluoroethylene grafts placed; only 4 of 10 (40%) grafts were patent on the left compared with 7 of 8 (88%) grafts patent on the right (P = .04). Left-sided grafts had increased macrophages at the arterial anastomosis (P = .0007). Left-sided perianastomotic arteries had thicker walls (0.74 vs 0.60 mm; P = .0211) with increased intima-media area (1.14 vs 0.77 mm2; P = .0169) as well as a trend toward 38% smaller luminal diameter (1.6 vs 2.5 mm; P = .0668) and 20% smaller outer diameter (3.0 vs 3.7 mm; P = .0861). Left- and right-sided perianastomotic veins were similar histologically, but left-sided veins had decreased expression of phosphorylated endothelial nitric oxide synthase (P = .0032) and increased numbers of α-actin-positive smooth muscle cells (P = .0022). CONCLUSIONS: Left-sided arteriovenous grafts are associated with reduced short-term patency compared with right-sided grafts in the Yorkshire pig preclinical model of arteriovenous prosthetic grafts. Laterality must be considered in planning and interpreting surgical preclinical models.