Objective To understand the value of pre-coating in artificial vessel endothelialization. Methods Literature concerning precoating in artificial vessel endothelialization was extensively reviewed. Results Pre-coating included chemical coatings(collagen, fibronectin, laminin, poly-l-lysin, gelatin andextracellular matrix), pre-clotting(plasma, blood, serum and fibrin glue), chemical bonding (heparin, RGD and lectins) and surface modification. Most of them could enhance the adhesion of the endothelial cells. Conclusion Pre-coating couldimprove endothelialization, but further research is needed to search for the appropriate concentration and incubation time.
ObjectiveTo analyze the causes and preventions of stent graft induced new entry (SINE) after thoracic endovascular aortic repair (TEVAR) for Stanford type B dissection, particularly from the standpoint of biomechanical behavior of stent graft. MethodsSINE was defined as the new tear caused by the stent graft itself, excluding those arising from natural disease progression or any iatrogenic injury from the endovascular manipulation. Twentytwo patients with SINE were retrospectively collected and analyzed out of 650 cases undergoing TEVAR for type B dissection from August 2000 to June 2008 in our center. An additional case included was referred to our center in 14 months after TEVAR performed in another hospital. ResultsTotally, there were 24 SINEs found in 23 cases, including SINE at the proximal end in 15 cases, at the distal end in 7, and at both in 1, and 6 patients died. The incidence was 3.4% ( 22/650) in our hospital, and the mortality was 26.1% (6/23). All 16 proximal SINEs was located at the greater curve of the arch and caused retrograde type A dissection. All 8 distal SINEs occurred at the dissected flap, and 5 of them caused enlarging aneurysm while 3 remained stable. All 23 cases had the endograft placed across the distal aortic arch during the primary TEVAR. ConclusionsSINE is not rare following TEVAR for type B dissection, and associates with a high substantial mortality. The stress yielded by the endograft seems to play a predominant role in its occurrence. It is of significance to take the stressinduced injury into account during both design and placement of the endograft.
Objective To evaluate surgical treatment of infected femoral artery pseudoaneurysm. Methods The data on surgical treatment of 45 patients with infected femoral artery pseudoaneurysm admitted from January 2003 to June 2008 were analyzed retrospectively. Fourty-three patients underwent operative treatment including excision of infected femoral artery pseudoaneurysm, exhaustive debridement and bypass graft with vascular prosthesis. Two patients were unavoidable to undergo removing of infected femoral artery pseudoaneurysm and ligating the proximal and distal artery of pseudoaneurysm because of severe infection and large volume. Results The patients were followed up from 3 to 12 months (mean 7.82 months). The limbs of all the patients underwent bypass graft with vascular prosthesis were salvaged successfully, patients of which had secondary wound healing and had not intermittent lameness. One of two patients performed ligation of artery was salvaged successfully but had severe intermittent lameness, another patient underwent high amputation above knee because of ischemic gangrene. Conclusion For infected femoral artery pseudoaneurysm, the operative treatment including excision of infected femoral artery pseudoaneurysm, exhaustive debridement and bypass graft with vascular prosthesis is effective and safe.
ObjectiveTo explore the role of chest wall arteriovenous graft (CWAVG) for establishing hemodialysis access in patients with end-stage renal disease.MethodsA retrospective analysis was made on the clinical data of 12 patients with end-stage renal disease who underwent CWAVG for establishing hemodialysis access between January 2014 and June 2015. There were 3 males and 9 females with an average age of 63.6 years (range, 54-82 years). The renal disease causes were chronic glomerulonephritis in 2 cases, hypertensive renal damage in 4 cases, diabetic nephropathy in 1 case, both kidney resection because of urinary tract tumors in 3 cases, and causes unknown in 2 cases. Hemodialysis time ranged from 1 to 144 months, with an average of 38.4 months. The 12 patients all underwent 1-14 times (mean, 4.2 times) anterior pathway failure in CWAVG, all of which were caused by repeated occlusion of dialysis pathway or poor vascular condition of upper extremity, resulting in the exhaustion of vascular pathway in upper extremity.ResultsAll patients were followed up 30-48 months (mean, 35.4 months). Two patients died, including 1 case of digestive tract hemorrhage, 1 case of heart failure. The other 10 CWAVGs were functionally useful for hemodialysis access about 6 weeks after operations. The primary patency rates at 6, 12, 18, 24, and 30 months were 83.3%, 75.0%, 33.3%, 33.3%, and 16.7%, respectively, and the cumulative patency rates at 6, 12, 18, 24, and 30 months were 83.3%, 75.0%, 50.0%, 33.3%, and 16.7%, respectively. Among 8 cases of CWAVG dysfunction, 6 cases had thrombosis, 1 case had seroma, and 1 case had vertebral artery stealing. Among them, 4 patients underwent hemodialysis using tunneled-cuffed catheter, 3 patients using fistula or graft on other limbs, and 1 patient was not treated with hemodialysis.ConclusionAlthough the long-term patency rate of CWAVG is yet to be further increased by improvement of treatment strategies, but it is still a supplementary option for end-stage renal disease patients with inadequate upper extremity venous access sites.
Objective To study the effect of preparation conditions for small-diameter polyurethane(PU) vascular graft on microstructure and mechanical properties. Methods The small-diameter microporous PU artificial vascular grafts were prepared by dipping and leaching method. The dimension and microstructure were controlled by changing mold diameter, PU materials, salt sizes, salt to polymer ratio, times of dipping layers etc. The mechanical properties of PU grafts including radical compliance, water permeability, longitudinal strength, burst strength, and suture tearing strength were measured and the effect of the graft dimension and microstructure on their properties were studied. Results The internal diameter of grafts prepared was 2-4 mm depending on mold diameter. The wall thickness was 0.6-1.2 mmafter dipping 4-8 layers. The density was 0.23-0.49 g/cm3. The pore was 42-95 μm in diameter. The porosity was 56%80%. The radical compliance was 1.2%-7.4%·13.3 kPa-1 and higher compliances could be obtained by using moreelastic polyurethane, higher salt to polymer ratio, longer diameter and less wall thickness. The water permeability, mainly depending on salt to polymer ratio,diameter, and wall thickness, was 0.29-12.44 g／(cm2·min). The longitudinal strength was 1.55-4.36 MPa correlating with tensile strength of polyurethane and salt to polymer ratio. The burst strength was 60-300 kPa also depending on tensile strength of polyurethane and salt to polymer ratio. The suture tearing strength was 19.5-96.2 N／cm2 depending on tensile strength of polyurethanebut not on the angle of tearing and graft axial directions. The compliance and water permeability of Chronoflex grafts were higher than those of PCU1500 grafts, but longitudinal strength, burst strength, and suture tearing strength of PCU1500 grafts were better than those of Chronoflex grafts. Conclusion Small-diameter grafts with proper pore sizes, porosity, matching compliance can be obtained by selecting PU materials and optimizing the preparation conditions.
To evaluate the implantation effect of artificial vascular grafts with recombinant fibrinolytic enzyme factor II (rF II)-immobil ized lumina in animal test. Methods Four mm internal diameter (ID) polyurethane (PU) artificial vascular grafts were prepared by di pping and leaching method. The micro-pore size and morphology of the graft walls were observed by SEM. The graft lumina were immobil ized with rF II. Twenty hybrid male dogs [weighing (20 ± 1) kg] were used for animal model of carotid artery defect and were randomly divided into 3 groups: rF II -immobil ized PU group, no rF II -immobil ized PU group and expanded polytetrafluoroethylene (ePTFE) group. The vascular grafts were implanted for repairing injured segments of carotid artery in dogs. The general health state of animals was recorded. At 30 days and 60 days,the patency rate of every group was calculated. At 60 days IDs were measured, cell prol iferation in neointima was inspected by l ight microscope, morphology on neointima was observed by SEM. Results The ID of the PU vascular grafts was (3.74 ± 0.06) mm, wall thickness was 0.4-0.6 mm, the wall density was 0.25 g/cm3, the porosity was 79.8%, racical compl iance was 8.57%/100 mmHg. In the wall, micropores were well distributed and opened-pores structure was observed. Pore size was (140 ± 41) μm in the outside layer, pore size was (100 ± 3) μm in the inside layer, thickness ratio of outside / inside layers was 2 ∶ 1, the pore size was (40 ± 16) μm on the lumina surface. After operation the wounds on neck healed, all the animals survived and had no compl ication. At 30 days and 60 days after implantation, the patency rate for rF II -immobil ized PU group were 100% and 66.7%, for no rF II -immobil ized PU group were 66.7% and 33.3%, and for ePTFE group were 67.7% and 0 respectively, but at 60 days there were thrombosis at anastamotic sites of some grafts occluded. Before operation the IDs for rF II-immobil ized PU group, no rF II -immobil ized PU group and ePTFE group were (3.74 ± 0.06), (3.74 ± 0.06) and (4.00 ± 0.03) mm, at 60 days after operation the IDs were (4.51 ± 0.05), (4.31 ± 0.24) and (4.43 ± 0.12) mm respectively, showing no statistically significant differences between 3 groups (P gt; 0.05). Histological inspection indicated that at 15 days a layer of plasma protein deposited on the lumina, at 30 days some cells adhered to the lumina, at 60 days neointima could be observed on the lumina. Thickness of the neointima became larger with implantation time. At 60 days neointima thickness at proximal end, middle site and distal end ofgraft were (560 ± 22), (78 ± 5) and (323 ± 31) μm respectively for rF II -immobil ized PU group. The results of SEM showed that neointima surface consisted of flat and long cells which long axes ranged with blood flow direction and was similar to lumina morphology of carotid artery of dog. Conclusion Immobil ization of rF II to lumina of grafts could enhance fibrinolytic activity and inhibited formation of thrombo-embol ia which led to an increase in patency rate after implantation.
OBJECTIVE: To investigate the clinical effects of revascularization in lower extremity for severe ischemia. METHODS: Fifty-six lower limbs with severe ischemia in 49 patients were evaluated retrospectively, who underwent surgical intervention from January of 1995 to December of 2000. By arteriography, the actual anatomic distributions of occlusive disease included infrarenal aorta-bicommon iliac arteries, abdominal aorta-bicommon iliac arteries, iliac artery, and femoral artery or femoropopliteal artery. The indication for surgery was disabling claudication, rest pain and gangrene. Fourteen limbs in 12 cases received arterialization of femoral venous system by artificial venous-arterial fistula. Artificial vascular grafts were implanted in 33 limbs of 28 cases, endarterectomy and patch profundaplasty were performed in 5 limbs of 5 cases, and primary amputation was carried out in 4 cases. RESULTS: During 38 months follow-up in average, 4 limbs were amputated within 52 revascularizated limbs, and accumulated amputation rate was 14.3%. Patency rate was 68.4% in arterial revascularization limbs (26/38 limbs), and limb survival rate was 94.7%(36/38 limbs) by procedure of artificial vascular grafts, endarterectomy and patch profundaplasty. Limb survival rate in procedure of artificial venous-arterial fistula was 85.7%(12/14 limbs). CONCLUSION: In treatment of severe lower extremity ischemia, the effective revascularization can be achieved by artificial vascular bypass, endarterectomy and patch profundaplasty, or arterialization of femoral venous system. Options in the surgical management should depend on individual. Arteriography is essential for revascularization and properly planning a practicable surgical approach.
ObjectiveTo compare the recent and mid-term results of two different treatments in bicuspid aortic valve (BAV) patients with dilated ascending aorta. MethodsFrom march 2007 to April 2014, there were totally 70 BAV patients received surgical treatment in Nanjing Cardiovascular Disease Hospital. According to the procedure of the ascending aorta, they were divided into two groups. As for group A which repaired the ascending aorta, there were 28 males and 9 females with an average age of 58.68±8.01 years. As for group B which replaced the ascending aorta, there were 25 males and 8 females with an average age of 54.18±11.97 years. And we compared perioperative clinical data and follow-up results of these two groups. ResultsThere were statistical differences between the two groups in cardiopulmonary bypass time, aortic cross clamping time, and ICU stay time (105.19±11.17 min vs. 180.94±32.10 min, P=0.000; 78.65±13.18 min vs. 110.24±29.64 min, P=0.000; 1.62±1.09 d vs. 3.58±2.89 d, P=0.001). And the time of the group A is shorter than that in the group B. Two patients in the group B died postoperatively, and the other 68 patients discharged. There was no significant difference in cumulative survival rate between the two groups (P=0.582). Postoperative following-up results showed that the ascending aortic diameter of both groups was smaller than that during the preoperative period. And at the latest time of the following-up, ascending aortic diameter was increased compared with pre-discharge in the group A (38.50±1.77 mm vs. 34.85±1.53 mm, P=0.007). But there was no increase in the group B. ConclusionWe suggests simultaneous treatment to dilated ascending aorta for BAV patients. Both the repair and replacement procedure could achieve satisfactory recent and mid-term results.