ObjectiveTo determine the influence of proximal aneurysm neck anatomy on typeⅠA endoleak follo-wing endovascular aortic aneurysm repair (EVAR) for infrarenal abdominal aortic aneurysm. MethodsFrom September 2007 to February 2014, 111 consecutive patients with non-ruptured abdominal aortic aneurysms were treated with EVAR. The preoperative CTA of abdominal aortic was obtained by every patient, and the three-dimensional imaging was reconstructed and measured by software of Osorix. Then, the relation between the recurrence of typeⅠA endoleak and the concerned data measured by Osorix was analyzed by the statistical software. ResultsThe recurrence of typeⅠA endo-leak was related to the proximal neck angle of the abdominal aortic aneurysm, which weren't related to the proximal neck diameter and variation rates, the mural thrombas and calcification rate, and the maximum diameter of abdominal aortic aneurysm by multivariate analysis. ConclusionsThe complicated proximal aneurysm neck anatomy is a major cause for the typeⅠA endoleak, the proximal neck angle of the abdominal aortic aneurysm is the independent factor. The applica-tion of EVAR depends largely on the shape of the proximal aneurysm neck.
Abstract: Objective To examine the cell viability and hemodynamic functions of the stented homograft valves preserved in liquid nitrogen. Methods Cell viability of the stented homograft valve preserved in liquid nitrogen after 3 months of preservation (experimental group，n=6) was examined using flow cytometer. Fresh homografts served as control group (n=6). We prepared three sorts of stented homograft valve(21#, 23#, 25#) preserved by liquid nitrogen. In vitro pulsatile flow tests were performed on valves of two groups. Effective opening area EOA),transvalve pressure gradient and regurgitation ratio were recorded at various flow volume, and compare with Perfect bioprosthetic valve. Results The results revealed that the death ratio of endothelial cell was 10.24%±1.71% in the experimental group, and 9.09%±2.72% in the control group (P=0.441). The death ratio of smooth muscle cell was 8.76%±1.82% in the experimental group, and 7.84%±0.59% (P=0.178) in the control group. The death ratio of total cell was 8.79%±1.44% in the experimental group, and 7.40%±0.49% in the control group (P=0.072). There were no significantly differences between two groups. The transvalve pressure gradient of two groups of valve depended on the flow volume, and increased with the flow volume increasing. The transvalve pressure gradient of the stented homograft valve was higher than that of Perfect valve. Regurgitation ratio of the stented homograft valve was bigger than Perfect valve’s. EOA had an increasing character when flow volume increased. EOA of the stented homograft valve was smaller than that of Perfect valve’s. Conclusion Liquid nitrogen can offer the benefit of cell viability of the stented homograft bioprosthetic valves. The stented homograft valve has salisfactory hemodynamic functions.
To address the conflict between the “fitness” and “feasibility” of body-fitted stents, this paper investigates the impact of various smoothing design strategies on the mechanical behaviour and apposition performance of stent. Based on the three-dimensional projection method, the projection region was fitted with the least squares method (fitting orders 1–6 corresponded to models 1–6, respectively) to achieve the effect of smoothing the body-fitted stent. The simulation included the crimping and expansion process of six groups of stents in stenotic vessels with different degrees of plaque calcification. Various metrics were analyzed, including bending stiffness, stent ruggedness, area residual stenosis rate, contact area fraction, and contact volume fraction. The study findings showed that the bending stiffness, stent ruggedness, area residual stenosis rate, contact area fraction and contact volume fraction increased with the fitting order's increase. Model 1 had the smallest contact area fraction and contact volume fraction, 77.63% and 83.49% respectively, in the incompletely calcified plaque environment. In the completely calcified plaque environment, these values were 72.86% and 82.21%, respectively. Additionally, it had the worst “fitness”. Models 5 and 6 had similar values for stent ruggedness, with 32.15% and 32.38%, respectively, which indicated the worst "feasibility" for fabrication and implantation. Models 2, 3, and 4 had similar area residual stenosis rates in both plaque environments. In conclusion, it is more reasonable to obtain the body-fitted stent by using 2nd to 4th order fitting with the least squares method to the projected region. Among them, the body-fitted stent obtained by the 2nd order fitting performs better in the completely calcified environment.
Objective To explore the clinical experience of endovascular treatment for arteriosclerosis obliterans (ASO) of lower extremities. Methods Endovascular treatment were performed on 22 patients (26 limbs) suffering from ASO which were diagnosed by magnetic resonance angiography (MRA). The clinical efficacy after operation was analyzed. Results Twentytwo lower extremities of 18 patients successfully accepted endovascular treatment with 12 stents planted without major complications. Four cases failed to endovascular treatment and 2 of them converted to bypass surgery. The clinical symptoms of limb ischemia vanished or significantly improved after treatment. The ankle brachial index (ABI) of affected extremities increased from 0.35±0.13 (before operation) to 0.70±0.15 (after operation), Plt;0.01. During the follow-up of 2-18 months, 3 cases suffered re-occlusion of artery of lower extremity, in them one case received drug treatment and 2 cases resolved by percutaneous transluminal angioplasty (PTA) and stenting again. Conclusion Endovascular treatment for ASO of lower extremities has such advantages as minimal invasiveness, reduced complications and repeatability. It may serve as a more promising choice of method to clinical treatment of ASO.
Objective To introduce the experience of treating 85 cases of stanford type B aortic dissection by endovascular implantment of stent-grafts，to provide more clinical evidence for endovascular repairment for stanford B type aortic dissections.Methods Imaging examination by computed tomography angiography （CTA） were done to obtain anatomical detail of dissection. Stent-grafts were implanted under the guide of DSA in all cases. The patients were followed-up for 3 months，6 months，12 months，and then annually by CTA examination to observe the complications and morphological changes of the aneurysm.Results The technical success rate was 95.3%（81/85），and the clinical success rate was 91.8%（78/85）. Eight patients died after operation in hospital，who were all in acute phase，and no patients of chronic phase died，there had statistic differences （P＜0.05）. The perioperative complications’ incidence of endovascular repair which happened in patients of acute phase was higher than that patients of chronic phase （38.2% vs.13.3%，P＜0.05）. Left subclavian artery were covered completely for 13 cases，and partially covered for 22 cases，there was no obvious cerebralvascular insufficiency. There were 41 patients of whom other tears which were not covered during operation exsited at abdominal aortic and one year following-up showed that at those section thromblization of false cavity was not clear. The rest of patients whose abdominal aortic didn’t exist tears hadn’t new tears appeared.Conclusions Regardless in the acute or chronic stage，endovascular therapy is an effective mathod of treating stanford type B dissection. However，implanting stent-grafts have a higher security in chronic period than doing that in acute period. If the right carotid artery，vertebra and Willis ring are smoothly，there is little need to set up a by-pass to left subclavian artery before endovascular repairment. For those patients that other uncovered tears exited，following-up should be a must，and further strategy should be studied and prepared in advance.
ObjectiveTo summarize the effects of endovascular intervention and artificial graft bypass for the occlusive superficial femoral artery disease. MethodsThe clinical data of 122 patients (136 limbs) with superficial artery occlusive disease underwent endovascular intervention or artificial graft bypass from January 2008 to April 2011 in this hospital were collected retrospectively. Age, TASCⅡgrading, condition of outflow tract, complications before and after procedures, hospital stay, primary patency rate, rate of amputation, and death rate were recorded. Results①Seventy-four limbs of 64 patients were accepted percutaneous transluminal angioplasty and stent graft (PTA/S group), 62 limbs of 58 patients were accepted femoral popliteal artery artificial graft bypass (artificial graft bypass group). Compared with the artificial graft bypass group, the age was significantly older (P < 0.05), TASCⅡA or B lesions were more (P < 0.05), TASCⅡC or D lesions were less (P < 0.05), the limbs with one or three outflow tracts were more (P < 0.05) in the PTA/S group. The limbs with two outflow tracts, and the patients combined with diabetes or hypertension or diabetes and hypertension had no significant differences between these two groups (P > 0.05).②There was no perioperative mortality in two groups. Compared with the artificial graft bypass group, the average hospital stay was sifnificantly shorter (P < 0.05), the 3-year death rate after procedure was higher (P < 0.05), the rate of postoperative incision infection was lower (P < 0.05), the primary patency rate of 36-month after operation was lower (P < 0.05) in the PTA/S group. The rate of amputation, the primary patency rates of 6-, 12-, and 24-month after operation had no significant differences between these two groups (P > 0.05). ConclusionsManagement of occlusive superficial femoral artery disease with femoral popliteal artery artificial bypass grafting exhibits a higher long term patency as compared with percutaneous stent graft. However, the hospital stay is longer than that in PTA/S group, and postoperative infection also occurres individually in artificial graft bypass group. Percutaneous transluminal angioplasty and stent graft has little trauma, faster recovery, shorter hospital stay, which is an important significance for the patients with too old or weak to accept femoral popliteal artery artificial graft bypass. But its long term patency rate needs to be improved.
Stent migration is one of the common complications after tracheal stent implantation. The causes of stent migration include size mismatch between the stent and the trachea, physiological movement of the trachea, and so on. In order to solve the above problems, this study designed a non-uniform Poisson ratio tracheal stent by combining the size and structure of the trachea and the physiological movement of the trachea to improve the migration of the stent, meanwhile ensuring the support of the stent. In this study, the stent corresponding to cartilage was constructed with negative Poisson's ratio, and the stent corresponding to the circular connective tissue and muscular membrane was constructed with positive Poisson's ratio. And four kinds of non-uniform Poisson's ratio tracheal stents with different link lengths and negative Poisson's ratio were designed. Then, this paper numerically simulated the expansion and rebound process of the stent after implantation to observe the support of the stent, and further simulated the stretch movement of the trachea to calculate the diameter changes of the stent corresponding to different negative Poisson's ratio structures. The axial migration of the stent was recorded by applying different respiratory pressure to the wall of the tracheal wall to evaluate whether the stent has anti-migration effect. The research results show that the non-uniform Poisson ratio stent with connecting rod length of 3 mm has the largest diameter expansion in the negative Poisson ratio section when the trachea was stretched. Compared with the positive Poisson's ratio structure, the axial migration during vigorous breathing was reduced from 0.024 mm to 0.012 mm. The negative Poisson's ratio structure of the non-uniform Poisson's ratio stent designed in this study did not fail in the tracheal expansion effect. Compared with the traditional stent, the non-uniform Poisson's ratio tracheal stent has an anti-migration effect under the normal movement of the trachea while ensuring the support force of the stent.
ObjectiveTo investigate the clinical efficacy of sarpogrelate hydrochloride in preventing restenosis after femoral artery stent implantation. MethodsTwo hundreds and fifty-one cases of ischemic disease of lower extremity (286 affected limbs in total) who got treatment in our hospital were collected, and were divided into prevention group(125 cases with 146 affected limbs) and control group(126 cases with 140 affected limbs) according kinds of medicine. At the basement of medicine in control group, cases of prevention group got treatment of sarpogrelate hydrochloride in addition. Comparison of related indexed was performed by SPSS 17.0 software. ResultsCompared with before treatment in prevention group, only foot skin ulcer and gangrene score decreased(P<0.05), and there were no significant difference on other indexes included visual anafogue scales(VAS), intermittent claudication distance score, ankle brachial index (ABI), and vascular stenosis score(P>0.05). But in control group, compared with before treatment, foot skin ulcer and gangrene score and ABI value decreased(P<0.05), the VAS score, intermittent claudication distance score, and vascular stenosis score increased(P<0.05). There were significant difference on the difference between after treatment and before treatment of all 5 indexes(P<0.05), that the changed value of foot skin ulcer and gangrene score was higher in prevention group, but lower on other 4 indexes. There were no untoward effect happened during treatment. ConclusionClinical effect of sarpogrelate hydrochloride in the prevention of restenosis of the femoral artery after stent implantation was significantly, and it can keep related indexes stable.
ObjectiveTo investigate the value of different minimally invasive surgical techniques, stent placement, laparoscopic surgery, and sustained-releasing 5-fluorouracil, in solving intestinal obstruction due to colorectal cancer. MethodsFrom May 2000 to May 2010, total 68 patients with obstructed colorectal cancers in three centers were treated in two ways in terms of the stage: The first, patients with resectable tumors underwent colorectal stent placement as a ‘bridge to surgery’ guided by enteroscope under X-ray. After clinical decompression and bowel preparation, laparoscopic radical resection was performed. The second, patients with unresectable tumors underwent rectal stent placement just for palliation. Sustained-releasing 5-fluorouracil was implanted into the local cancerous intestinal tract through stent walls. ResultsFifty-one of 52 patients underwent laparoscopic radical resection successfully following stent placement, while one failed and died during follow-up 93 d postoperatively. Forty patients with successful laparoscopic surgery were followed up in 3 to 36 months (with an average of 15 months) without tumor planting in the incision, postoperative local recurrence or anastomotic stricture. Fifteen unresectable patients and one high-risk, intolerable patient underwent rectal stent placement and implantation of sustained-releasing 5fluorouracil. During follow-up 3 to 24 months (with an average of 14 months), 11 died, who survived for (350±222) d (range 101-720 d), and 5 were still alive for 3 to 13 months (with an average of 9 months) without intestinal obstruction. ConclusionsLaparoscopic surgery combined with stent placement is an effective and safe procedure for resectable obstructed colorectal cancer. For unresectal obstructed rectal cancer, rectal stent placement combined with sustained-releasing 5-fluorouracil can prolong survival time avoiding colostomy.
Objective To design a novel stentless porcine aortic bioprosthesis and test the feasibility and its function in vitro after the valve was implanted by a modified method. Methods Six stentless porcine aortic bioprosthesis were divided into two groups according to different implantation, single layer suture group: new improvement stentless porcine aortic bioprosthesis sutured with single layer was implanted; double layer suture group: stentless porcine aortic bioprosthesis developmented by our laboratory used double layer suture was implanted. Each group contained three scales: 23 mm ,25 mm and 27 mm. Analogue ex vivo aortic valve replacement was performed , the feasibility of the new implantation was detected. Effective orifice area, transvalvular pressure gradient and regurgitation ratio were recorded at the cardiac output of 2.0 L/min, 3.5 L/min, 5.0 L/min and 7.0 L/min under the guideline of International Organization for tandardization （ISO）5840. Results The average aortic valve implantation time used for single layer suture and tradition double layer suture were 50 min and 70 min respectively. The transvalvular pressure gradient in the single layer suture group were significantly lower than those in double layer suture group under the flow of 5.0 L/min in 23 mm valve and 27 mm valve （13.51±0.51 mm Hg vs. 14.44±0.99 mm Hg, 7.36±0.19 mm Hg vs. 7.53±0.28 mm Hg；P＜0.01）;and the effective orifice area in the single layer suture group were larger than those in double layer suture group in the same case(1.87±0.06 cm2 vs. 1.76±0.08 cm2, 2.26±0.07 cm2 vs. 2.16±0.05 cm2；P＜0.01). There was no statistically difference in other parameters between both groups. Conclusion The novel design of new improvement stentless porcine aortic bioprosthesis used single layer suture has good hemodynamic characteristics as the nature structure . The modified suture method decrease the implantation time.Nemerical data of the evaluation in vitro show that the difference between single layer suture group and double layer suture group in effective orifice area,transvalvular pressure gradient and regurgitation ratio haveno statistical significance. This experiment is the foundation of the animal and clinical experiment in the future.