• Maxillofacial Plastic and Reconstructive Surgery
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• v.23 no.2
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• pp.137-143
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• 2001

The effect of topical heparin application and vascular freezing on thrombosis was evaluated in the femoral vein of rabbits. The femoral veins were crushed, incised transversely and treated by 4 different ways; 1) group 1, heparin treated only, 2) group 2, frozen only, 3) group 3, heparin treated and frozen, 4) group 4, treated with saline as control. The patency was evaluated by empty-and-refill test and thrombus formation was judged by stereoscopic and SEM observation. The results obtained were as follows: 1. Thirty minutes after suture, the patency was more improved in the three groups than the control, but there was no significant difference among groups. 2. Three days after suture, the patency was more improved in the three groups than the control, and was prominent in group 1 and group 3 (P<0.05). 3. Significantly reduced thrombus could be seen in most case of group 3. These results suggest that topical application of heparin and vascular freezing is effective in reducing thrombus formation in microsurgery of vein.

• Archives of Reconstructive Microsurgery
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• v.9 no.2
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• pp.179-185
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• 2000

In the field of microsurgery, the vascular obstruction of the microvascular anastomosis by thrombus is one of the most important complication. The purpose of this study is to compare the effect between aspirin and prostaglandin $E_1$($PGE_1$) which act as the peripheral vasodilatation and platelet disaggregation. We have used total 48 white male rats and divided them into three gruoups(A, B and C group). Each group consists of 16 rats respectively. A group is as control, B group is medicated with aspirin(3.0mg/kg/day) and C group with $PGE_1(1.2{\mu}g/kg/day)$. The gross and histopathologic findings at anastomosed site were observed on 3, 5, 10 and 15 days after vascular anastomosis and the results were obtained as the followings. 1. The microvascular patency rate is 81.2% in control group, 93.8% in aspirin group and 100% in $PGE_1$ group. 2. On the histologic examination, the formation of mural thrombus is decreased both in the aspirin and $PGE_1$ group as comparing with the control group and also the hypertrophy of the intima forming from media is less formed in $PGE_1$ group than aspirin group and the degree of thickeness is also less. 3. The fibrosis of media is less observed in $PGE_1$ group than aspirin group. According to the above results, the application of $PGE_1$ to the microsurgery is considered to be effective on the prevention of the thrombus formation and on providing high patency rate.

• Journal of Chest Surgery
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• v.54 no.6
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• pp.500-508
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• 2021

Background: The major limitation of arteriovenous graft access is the high incidence of thrombotic occlusion. This study investigated the outcomes of our salvage strategy for thrombosed hemodialysis arteriovenous grafts (including surgical thrombectomy with balloon angioplasty) and evaluated the efficacy of intragraft curettage. Methods: Salvage operations were performed for 290 thrombotic occluded arteriovenous grafts with clinical stenotic lesions from 2010 to 2018. Of these, 117 grafts received surgical thrombectomy and balloon angioplasty from 2010 to 2012 (group A), and 173 grafts received surgical thrombectomy and balloon angioplasty, with an additional salvage procedure using a curette and a graft thrombectomy catheter, from 2013 to 2018 (group B). Outcomes were described in terms of post-intervention primary patency and secondary patency rates. Results: The post-intervention primary patency rates in groups A and B were 44.2% and 66.1% at 6 months and 23.0% and 38.3% at 12 months, respectively (p=0.003). The post-intervention secondary patency rates were 87.6% and 92.6% at 6 months and 79.7% and 85.0% at 12 months, respectively (p=0.623). Multivariate Cox regression analysis demonstrated that intragraft curettage was a positive predictor of post-intervention primary patency (hazard ratio, 0.700; 95% confidence interval, 0.519-0.943; p=0.019). Conclusion: Surgical thrombectomy and balloon angioplasty showed acceptable outcomes concerning post-intervention primary and secondary patency rates. Additionally, intragraft curettage may offer better patency to salvage thrombotic occluded arteriovenous grafts with intragraft stenosis.

• Journal of Chest Surgery
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• v.51 no.2
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• pp.122-129
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• 2018

Background: For hemodialysis patients with end-stage renal disease (ESRD), it is important to construct an efficient vascular access with a superior patency rate. This study investigated the factors influencing the efficiency of arteriovenous fistulas (AVFs) constructed using an autologous vessel and evaluated the necessity of ultrasonography as a preoperative tool for AVF construction. Methods: A retrospective analysis was performed of 250 patients in whom an AVF was constructed using an autologous vessel due to ESRD at our institution from January 2009 to April 2016. Results: The 1-, 3-, and 5-year patency rates for all subjects were 87.6%, 85.6%, and 84.4%, respectively. The patients who underwent a preoperative evaluation of their vessels via ultrasonography had better patency rates than those who did not. Superior patency rates were found in patients under 65 years of age or with an anastomotic vein diameter of 3 mm or more. The 1-year patency rate and the diameter of the anastomotic vein showed a positive relationship. Conclusion: Ultrasonography is strongly recommended for AVF construction, and efforts should be made to increase the patency rate in patients over 65. Superior clinical results can be expected when an AVF is made using an autologous vessel with an anastomotic vein diameter of at least 3 mm.

• Journal of the Korean Association of Oral and Maxillofacial Surgeons
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• v.33 no.4
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• pp.340-349
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• 2007

Free flap transplantation with microvascular anastomosis has been successfully performed by development of surgical technique, materials and postoperative monitoring equipments of flap. But success rate of microvascular anastomosis is influenced by various factors, and failure rate is about 5-10%. The most influential factor for success rate is surgical technique and other factors that influence failure of microvascular anastomosis are ischemic time of free flap, thrombus formation of anastomosis region and vascular spasm. In this study, vascular patency and thrombus formation in experimental micro-venous anastomosis, and endothelial repair were observed with histologic analysis, scanning electron microscopy, transmission electron microscopic examination. The results were obtained as follows: 1. In vascular patency test in 30 minute and 7 days after micro-venous anastomosis with heparin irrigation, all of 12 anastomosis site were good vascular patency. 2. In thrombus formation in 2 weeks group(Experimental I), 2 site of 6 cases were observed thrombus, and in 4 weeks group(Experimental II), 1 site of 6 cases were observed thrombus. 3. In histologic examination, normal vein(Control Group) showed continued internal elastic lamina, well formed thick smooth muscle layer and connective tissue. The group of 2 weeks after microvenous anastomosis(Experimental I) showd locally recovered internal lamina, discontinued internal lamina, disorganized smooth muscle cells and granulation tissue around suture silk. In the group of 4 weeks after micro-venous anastomosis(Experimental II), anastomosis site showed almostly continued internal lamina, disorganized smooth muscle cells and cicartrized tissue around suture silk. 4. In scanning electron microscope examination in 2 weeks(Experimental I) after micro-venous anastomosis, mesh fibrin formation showed near to endothelial cells, and in 4 weeks after micro-venous anastomosis(EXperimental II), numerous blood cells and fibrin mesh formation was seen associated with irregular endothelial cell arrangement. 5. In transmission electron microscope examination in 2 weeks after micro-venous anastomosis(Experimental I), irregular arrangement of smooth muscle cells was seen adjacent to collagenized tissue around suture silk. In 4 weeks after micro-venous anastomosis(Experimental II), denuded venous wall composed of relatively well arranged smooth muscle cells was covered by endothelial cells, but fibroblast cells and foreign body giant cells near to suture silk was remained. From the results obtained in this study, results of good vascular patiency and anti-thrombotic effect of heparin were obtained as a local irrigation solution, and repair of venous endothelial cell was observed in 2 weeks after micro-venous anastomosis.

• Journal of the Korean Society of Radiology
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• v.84 no.1
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• pp.197-211
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• 2023

Purpose To evaluate the circuit patency after nitinol bare-metal stent (BMS) placement according to the type of access and location of the stent in dysfunctional hemodialysis access. Materials and Methods Between January 2017 and December 2019, 159 patients (mean age, 64.1 ± 13.2 years) underwent nitinol BMS placement for dysfunctional access. The location of stents was as follows: 18 brachiocephalic vein, 51 cephalic arch, 40 upper arm vein, 10 juxta-anastomotic vein, 7 arteriovenous (AV) anastomosis, and 33 graft-vein (GV) anastomosis. Circuit patency was evaluated by the Kaplan-Meier method, and cox regression model. Results A total of 159 stents were successfully deployed in 103 AV fistula (AVF) and 56 AV graft (AVG). AVG showed lower primary and secondary patency at 12-months compared with AVF (primary patency; 25.0% vs. 44.7%; p = 0.005, secondary patency; 76.8% vs. 92.2%; p = 0.014). Cox regression model demonstrated poorer primary patency at 12 months after stenting in the cephalic arch and GV anastomosis compared with the other sites. Conclusion AVF showed better primary and secondary circuit patency at 12 months following the placement of BMS compared with AVG. Stents in the cephalic arch and GV anastomosis were associated with poorer primary patency at 12 months compared to those in other locations.

• Proceedings of the KOSOMBE Conference
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• v.1997 no.11
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• pp.478-481
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• 1997

A technique or the preparation of porous polyurethane vascular prostheses was investigated. Small-diameter vessels are not in general clinical use due to their limited long-term biocompatibility and low patency rates in experimental trial. These limits are mainly due to the failure of mechanical unction of the vascular grafts. This failure has been suggested to result partially from compliance mismatch. The long-term patency is considered to depend critically on the properties of the material and the fabrication process of the graft. So the control of pores is very important and main points to develop a available vascular grafts. Two-kind polymer sheets was compared. One was the porous PU-sheet made at room temperature by the solvent/non-solvent exchange. And the other was the porous PU-sheet which was fabricated by thermal phase transition and solvent-/non-solvent exchange using the thermal controller. The polymer sheets had a uniform pore size and pore occupation. According to the result of the above experiments, polyurethane solution was injected into a mold designed or U-type tube. The average pore size and pore occupation were easily changed by changing polyurethane concentration, freezing temperature, and methods. This technique can give a proper pore size ($10{\sim}45\;{\mu}m$) or tissue in growth, and suitable compliances or matching with arteries and veins. Besides, the fabrication of more complicated shaped vessels such as the U-type vascular grafts is easily controlled by using the fixed mold. this method might give a desired compliant graft or artificial implantation with the presently valid medical polymers.

• Journal of Chest Surgery
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• v.32 no.10
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• pp.943-946
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• 1999

There was no significant difference in morbidity and mortality between those that received simultaneous operation for coronary artery disease and peripheral vascular disease versus those that received coronary artery bypass graft alone. Simultaneous operation is also cost effective. A 46 year-old patient with resting chest pain and intermittent claudication was diagnosed as unstable angina and Leriche's syndrome. We performed simultaneous revascularization for coronary artery stenosis with internal mammary artery and right gastroepiploic artery and a bifurcated vascular graft interposition between in the aorta, left common iliac and right femoral arteries for Leriche's syndrome. The postoperative coronary angiogram and aortogram revealed a good patency of the arterial conduits and vascular graft. He has been followed for 12 months without any problem.

• Journal of Chest Surgery
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• v.33 no.1
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• pp.7-19
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• 2000

Background :To assess the accuracy of Electron-Beam Tomography(EBT) in following evaluation of the pulmonary vascular system after a shunt operation in the cyanotic con-genital heart disease with pulmonary stenosis or pulmonary atresia. Material and Method : Sixteen patients(M:F=11:5) who received Blalock-Taussig(n=8) bidirectional cavo-pulmonary shunt(n=10) and unifocalization (n=2) were ncluded in the study. We evaluated the patency of the shunt the morphology of intrapericardial and hilar pulmonary arteries(PA) peripheral pulmonary vascularity by background lung attenuation and the abundance of arterial & venous collateral. Angiography(n=12) and echocardiography(n=20) were used as the gold standard for the comparison of EBT results. Result: EBT was consistent with angiogram/ echo in 100% of the evaluation for the patency of the shunt and in 12(by angiogram 100%) and 19(by echo 95%) for the detection the hypoplasia stenosis or interruption of central PA In measuring of PA EBT and angiogram corrlated(r=0.91) better than EBT-echo(r=0.88) or echo-angiogram(r=0.72) Abundant systemic arterial collateral were noted in 4 and venous collateral in 3 cases. In evaluating the peripheral pulmonary vascularity the homogenous and normal-ranged lung attenuation(m=6) decreased but homo-genous attenuation(n=1) segment-by-sgment heterogeneous attenuation(n=3) homogenous but asymmetrical attenuation(n=3) segment-by-segment heterogeneous attenuation(n=3) homogenous but asymmetrical attenuation(n=3) and venous congestion(n=2) were observed nd 12 of them were compatible with the blood flow pattern revealed by cardiac catheterization. Conclusion: EBT was accurate in the integrated evaluation of the pulmonary vascular system after the shunt including the patency of the shunt operaion the morphology and dimension of the central and hilar PAs and the loco-regional pulmonary flow in the lung parenchyma. It suggests the useful information about the need of secondary shunt operation the proper timing time for total repair and the need of interventional procedure prior to total repair.

• Journal of Chest Surgery
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• v.19 no.3
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• pp.412-420
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• 1986

From 1968 through September 1986, the authors have experienced 34 cases of peripheral arterial surgery using various vascular grafts. Almost all patients [32] were men, and age distribution was variable according to the disease entities. There were twenty eight cases of chronic occlusive peripheral vascular disease including ASO [21], Buerger`s disease [6], Aortoenteric fistula complicating infrarenal abdominal aortic aneurysm [1], four cases of vascular trauma, one case of acute arterial embolism [1] and one case of unknown etiology. The indications of operations for chronic vascular disease was intermittent claudication in 48%, rest pain in 45%, ischemic pregangrene or gangrene in 28%, and sensory change in 10% of patients. Types of operation used were arterial bypass in 28 cases [Aortobifemoral in 5, Aortoiliac in 3, Aortofemoral in 4, Aortoiliac with Aortofemoral in 1, Femorofemoral in 1, Femoropopliteal in 8, Femoroperoneal in 2, Axillofemoral in 3 cases of patients], graft interposition in four and patch angioplasty in three cases. Thirty four prosthetic vascular grafts including Dacron, Gore-Tex, Nylon and two autogenous saphenous vein graft and patch were used for vascular reconstruction in thirty four patients. Unfortunately recently performed one vein bypass was failed immediate postoperatively due to severity of disease and poor case selection. The authors experienced five post operative complications: wound infection [1], graft infection [1], bleeding [1], great saphenous neuralgia [1], pseudoaneurysm [1]. Twenty two of thirty four patients were followed up for more than one month and their cumulative patency rate was 81% [17/22] at 1 month and, 31% [7/22] at 5 month.