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OBJECTIVE: Small diameter vascular grafts (＜ 6 mm) are used predominantly in revascularization and reconstructive procedures. The small diameter vascular grafts already used in our clinical practice include autologous veins or arteries, polyethylene terephthalate (Dacron) and expanded polytetrafluoroethylene (ePTFE) synthetic vascular grafts. Unfortunately these vascular grafts all have some disadvantages that prohibit their uses. Therefore search for ideal small diameter vascular grafts has become the focus in recent years.DATA SOURCES: A computer-based online search of Pubmed database was undertaken to identify the articles about small diameter vascular grafts published in English between January 1990 and January 2007 with the key words of "prosthetic graft, vascular bypass graft, small diameter vascular graft, tissue engineering".STUDY SELECTION: The data were selected firstly to choose the full-text of articles met the criteria. Inclusion criteria: ① Articles about biological vascular grafts; ②Articles about synthetic vascular grafts; ③Articles about small diameter tissue engineering blood vessels. Exclusion criteria: Repetitive or analogical articles or case reports.DATA EXTRACTION: Totally 113 articles on small diameter vascular grafts were collected and 41 met the inclusive criteria after eliminated the repetitive or similar studies or case reports.DATA SYNTHESIS : Although biological vascular grafts have the outstanding advantages, such as superior long-term patency, relatively resistant to infection, minimal thromboembolism, etc., they also have predominant disadvantages of limited availability, durability and aneurysm formation. Dacron and ePTFE are currently the standard synthetic vascular grafts in the vascular bypass surgery, but their immediate or long-term patency rates are relatively poor due to compliance mismatch, thrombogenicity and poor haemodynamics, especially when they are used in small diameter revascularization and reconstructive procedures. Thus, various modifications have been applied to Dacron and ePTFE grafts to improve their function. In recent two decades, the emergence of tissue-engineering technology has made the development of a novel biologically viable vascular substitute feasible, and it may prove to be the ultimate solution for better small-diameter vascular grafting.CONCLUCTION: So far there is no completely biodegradable small diameter vascular graft suitable for the arterial circulation in humans. Construction of an ideal small-diameter vascular graft will require an interdisciplinary effort requiring critical contributions from biologists, engineers, and clinicians, with strong collaborations among these 3 fields being crucial to success.
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Objective To evaluate the mid-term outcomes of endovascular repair of descending thoracic aortic aneurysm(DTAA) in high-risk patients.Methods Twenty four patients with DTAA received stent-grafts implantation between January 2001 and July 2007 and their clinical data were retrospectively analyzed.All patients were considered high-risk for open surgical repair due to the location or rupture of the aneurysm,high age and severe comorbidities.Spiral computed tomography angiography and 3-dimentional reconstructions were performed at 1,3,6 and 12 months postoperatively and thereafter every year.Results The primary operational success rate was 100%.There were 2 deaths(8.3%) during perioperative period due to multiorgan failure and acute myocardial infarction respectively.Two(8.3%) patients had severe post-operational complications(1 stroke and 1 acute renal insufficiency).Eleven cases of type Ⅰ(46%) endoleak were detected immediately after the operation and among them,the endoleak disappeared after balloon dilatation in 3 cases while the other 8 patients were treated conservatively.Follow-up of 1 to 60 months(mean 18.6?4.2 months) was completed in 19 patients(79.2%).Stent displacement with type Ⅰ endoleake was found in 1 patient at 4 years after the operation and delayed type Ⅲ endoleak occured in another patient at 2 years post-operation.Both patients received endovacular repair again and the endoleaks were closed successfully.One patient died of colon cancer during the follow up.Complete thrombosis of the thoracic aneurysm sac and no stent migration or endoleak was found on the followup CT at 3 months after the operation in all the patients.The decrease in maximal aneurysm diameter was 0-18 mm(mean 6.3?3.1 mm).The prosthetic vascular grafts implanted in 4 patients with preliminary carotid subclavian bypass surgery were patent during the follow-up period.Conclusion Treatment of descending thoracic aortic aneurysm in high-risk patients with endovascular approach showed acceptable early mortality and morbidity and may be considered as a treatment alternative for carefully selected patients.
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Objective To evaluate diagnostic procedures and clinical outcomes of vascular prosthetic and stent graft infection. Methods Clinical data of 15 cases suffering from vascular graft infection between 1985 and 2005 were retrospectively analyzed. Results The rate of vascular graft infection was 1. 14% among our series of 1316 cases of revascularizations. Vascular graft infection occurred within 4 months after graft implantation in 13 cases (86. 7% ). Graft infection developed after 4 months postoperatively in the other 2 cases ( 13. 3% ). Clinical manifestations included wound infection with vascular graft exposure, inguinal swelling or fistula, fever or sepsis, anastomotic hemorrhage, pulse loss of vascular graft or distal lower extremity and gangrene of distal lower extremity. Surgical treatment included en bloc removal of the infected graft and surrounding infected tissue, drainage and local irrigation with antibiotic solution, graft en bloc removal and primary amputation; Graft en bloc removal, drainage and revascularization with a saphenous vein or a new prosthetic graft; Aggressive debridement and local irrigation with antibiotic solution. Four patients died and the others recovered successfully. Conclusion The infection of a vascular graft is a rare complication in vascular surgery. Early diagnosis and aggressive surgical management can improve its prognosis.