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At least 37 records · Page 2Linked to original sources
PubMed1985

Influence of vessel clips on vascular patency in microarterial grafts less than 0.5 mm in external diameter.

Autogenous interpositional microarterial grafting of 140 saphenous branches of albino rat femoral arteries with an external diameter of 0.3 to 0.5 mm (mean 0.45 +/- 0.06 mm) resulted in an immediate patency rate of 100%. The patency rate observed at 72 hours was 64.3%. The late patency rate was related to blade tip pressure of the double approximator clip used in the microanastomosis. The patency rate with a clip with a blade tip pressure of 22 gm was 52.7% and that with a clip with a blade tip pressure of 2 gm was 77.3%. When arterial occlusion lasted less than 30 minutes, the late patency rate was 76.9% to 78.3%. If arterial occlusion lasted for as long as 1 hour, the late patency rate of vessels occluded by a clip with a blade tip pressure of 22 gm dropped to 27.8%. These results demonstrate that an interpositional microarterial graft as small as 0.5 mm in external diameter is clinically feasible.

Animals↗
PubMed1977

Correlation of myocardial contraction band necrosis and vascular patency. A study of coronary artery bypass graft anastomoses at branch points.

Eleven patients who died within 1 week of operation and in whom saphenous vein bypass graft anastomoses were located at or extended across coronary artery branch points were studied at autopsy. New surgically introduced narrowings of greater than 75% in one branch of the 13 anastomoses studied were more frequent (six of eight) when the arteriotomy extended into a branch artery than when the arteriotomy ended proximal to the flow divider of the branch point (zero to five). Obstruction was most frequently caused by suture compression of the arterial lumen. In five of the six anastomoses, where one branch contained a significant new narrowing and the other did not, a striking difference in the severity of myocardial contraction band necrosis in the distribution of the two arteries was found. In each such case the severe necrosis was in the distribution of the patent branch artery and the obstructed branch had slight or trivial injury. The results are interpreted as showing that myocardium that has the potential for developing contraction band necrosis may not develop it if the reflow phase is suppressed.

Adult↗
PubMed1988

Vascular medullary patency in free vascularized bone grafts: CT scan experimental study.

In an experimental study using 13 mongrel adult dogs, 6 cm of the anterior part of the left ninth rib were harvested, including the posterior intercostal vessels. The grafts were transferred, based on the periosteal circulation alone, to a previously induced femoral head ischemic necrosis. Microsurgical anastomoses were performed between the posterior intercostal vascular bundle and the caudal gluteal vessels at the recipient thigh zone. Using a high resolution CT scan and morphologic evaluation, it was demonstrated that the medullary circulation network filled on contrast medium. The entire cortex and medullary cavity were supplied from endosteal vessels coming from a reversed periosteal blood flow.

Anastomosis, Surgical↗
PubMed1986

Maintenance of vascular access patency in pediatrics.

The patency of vascular access shunts and fistulae has been prolonged by a combined surgical and radiological approach that includes percutaneous transluminal angioplasty (PTA), surgical revision, thrombectomy, and thrombolysis. Over the last 3 years, 35 vascular accesses in 27 patients were found to have angiographic abnormality. PTA was performed 32 times on 19 accesses and 7 PTAs resulted in patent accesses by the end of the study. Surgical revision was performed 9 times on 8 accesses and 2 of the surgical revisions resulted in a patent access by the end of the study. Concerning Thomas femoral shunts, PTA prolonged the patency by 2.2 months and surgical revision by 3.8 months per procedure. Concerning arteriovenous (AV) fistulae, PTA prolonged the patency by 4.3 months and surgical revision by 3.5 months per procedure. A combination of procedures effectively doubles the duration of patency of Thomas femoral shunts and almost triples the duration of patency of AV fistulae in children. Forty-one percent of these accesses remain open 1 year following the initiation of these procedures.

Adolescent↗
PubMed1992

Maintenance of patency after vascular trauma by topical irrigation with a peptide homologous to the carboxy-terminus of the fibrinogen gamma chain.

Synthetic peptides with amino acid sequences homologous to the carboxy-terminal sequence of the gamma chain of human fibrinogen were evaluated for their capacity to inhibit thrombus development. A 21-residue peptide effectively inhibited surface-mediated fibrin clot propagation in vitro. Since this effect was localized to the surface, we proceeded with in vivo evaluation, using site-specific topical application only. In a rat model of arterial trauma and microvascular repair, topical application of the 21-residue peptide significantly reduced the rate of thrombosis to 17%, as compared with a control rate of 83%; in comparison, a 12-residue homologue reduced the thrombosis rate only modestly to 61%, which was not significant compared with the control rate. These results indicate the feasibility of antithrombotic therapy with topically applied agents, an approach that may obviate the use of systemic anticoagulation in extremity-replantation surgery.

Administration, Topical↗
PubMed1987

Determination of the patency of vascular prostheses implanted in the rat aorta by means of ultrasonic blood-flow measurements.

Patency of vascular prostheses implanted in the rat aorta is usually confirmed by reoperation and inspection of the distal stump of the aorta for pulsations. Repeated reoperation on rats included in long-term investigations is not possible because of the increasing formation of scar tissue and adhesions at the site of the distal aorta. Consequently, noninvasive ultrasonic Doppler measurement was investigated to determine whether this method could provide accurate information about the patency of an implanted prosthesis. A total of 37 rats with 10-cm-long prostheses implanted in the aorta (groups C nonsupported prostheses, n = 12; and D supported prostheses, n = 25), eight normal nonoperated controls (group A), and three rats with a ligated aorta (negative controls, group B) were studied over a period of 12 weeks. The Dopplerrecordings obtained in the normal animals served as controls for the recordings of rats with an implanted prosthesis. A prosthesis was considered patent if the Dopplermeasurements obtained from the femoral artery resembled that of the normal pattern. In seven cases a prosthesis was suspected to be occluded since the Dopplermeasurements resembled those obtained after aortic ligation. Autopsy confirmed the Dopplermeasurements in all cases. No Dopplermeasurements returned to normal in the femoral artery in the aorta-ligated rats even after longer periods post-operation. It is concluded that Dopplermeasurements can accurately provide information about the patency of a vascular prosthesis implanted in the rat aorta.

Animals↗
PubMed1988

Histologic comparison of experimental coronary artery bypass grafts. Similarity of in situ and free internal mammary artery grafts.

This study compares patency and histologic structure of in situ internal mammary artery grafts, free internal mammary artery grafts, stripped, free internal mammary artery grafts, and stripped, free superficial femoral artery grafts (a muscular artery model) in a canine model of coronary artery bypass. Twenty-four adult mongrel dogs underwent bypass of the circumflex coronary artery with one of the above grafts. Three months postoperatively, graft patency was assessed by angiogram, and postmortem specimens were studied by intraluminal injection of a dilute barium solution proximal to the graft. Proximal, mid, and distal segments of each graft were examined microscopically. In situ internal mammary artery grafts and free internal mammary artery grafts were not significantly different in regard to patency, vascular wall cellular structure, or perfusion of the vasa vasorum. The stripped, free internal mammary artery group had a higher incidence of thrombosis, intimal thickening, and medial injury than the pedicled (in situ and free internal mammary artery) grafts. This difference may be due to early vascular wall ischemia as a result of poor early perfusion of the vasa vasorum. The stripped, free superficial femoral artery grafts were all patent, but all had adventitial injury.

Angiography↗
PubMed1977

Improvement in experimental vascular graft patency by controlled defibrinogenation.

A sensitive animal model was used to investigate treatment designed to improve vascular graft patency. A Dacron graft was inserted into the infrarenal vena cava of 30 rabbits. Half were treated with subcutaneous Arvin for 28 days after operation. This produced a significant lowering of the post operative plasma fibrinogen. The patency rate of the grafts in the treated rabbits was significantly greater than in the control rabbits.

Ancrod↗
PubMed1987

A reliable technique of free vascularized sural nerve grafting and preliminary results of clinical applications.

A technique of harvesting a free vascularized sural nerve graft based on either the cutaneous branch of the peroneal artery or the muscular perforating branch of the posterior tibial artery is described. Anatomic dissections with dye injection studies confirmed the reliability of this blood supply to a 25 cm long segment of the sural nerve. The sural nerve can be sectioned into as many as four segments while safely maintaining each segment's vascularity through intact fascia. A skin monitor can be elevated with the nerve to monitor vascular patency. The free vascularized sural nerve was used to reconstruct 16 nerve defects in the upper extremity. All 13 skin monitors elevated have survived. Early follow-up (range, 2 to 31 months) has shown encouraging clinical recovery. Although our preliminary results are difficult to compare with other series, this technique appears promising in clinical circumstances when interfascicular nerve grafting is indicated but the recipient bed is heavily scarred and poorly vascularized.

Adolescent↗
PubMed2006

Effect of secondary interventions on patency of vascular access sites for hemodialysis.

PURPOSE: To determine the impact of secondary procedures performed to maintain arteriovenous fistula (AVF) and arteriovenous graft (AVG) patency. METHODS: There hundred and eighty six vascular access procedures were retrospectively evaluated. 156 (40.4%) patients required radiological interventions to treat acute thrombosis, swelling of the extremity with the access site, insufficient hemodialysis, or stenosis at an anastomotic site. RESULTS: The 386 cases comprised 106 AVGs and 280 AVFs. In 138 of the 156 cases, which required a radiological intervention, the treatment was successful and saved the vascular access site. The unassisted post-intervention patency time for these 138 successful cases was 13.1 +/- 12 months (range, 1-65 months). Twenty-nine (63%) of the 46 access sites treated with surgical thrombectomy were saved. CONCLUSIONS: Frequent, regular follow-up of hemodialysis patients with vascular access sites is the best way to diagnose problems early and allow the best chance of long-term function.

Adult↗
PubMed1994

The effect of comorbid conditions on hemodialysis access patency.

Vascular access complications are a continuing source of hospitalization and morbidity in chronic dialysis patients. Several factors have been identified that are associated with complications in patients with native vein and prosthetic bridge arteriovenous graft fistulas. Early failure of native vein arteriovenous fistulas most consistently are related to small blood vessels. It remains unclear whether other comorbid factors play a role in complications of this fistula type. Prosthetic bridge fistulas are frequently placed in the United States and are associated with frequent complications. Factors most consistently associated with higher complication rates are diabetes mellitus, older age, and black race. Antiphospholipid antibody-associated syndromes and erythropoietin therapy have also been suggested as contributing factors. In addition, elevated lipoprotein(a) and hypoalbuminemia have been found to be associated with an increase of prosthetic graft thrombosis in white and Hispanic dialysis patients. This information strongly suggests that fistula complications are multifactorial. An improved understanding of the mechanisms of these associations may aid in the delineation of the pathogenesis and an improvement in the outcome of this important problem.

Aging↗