Antibodies to prothrombin in antiphospholipid syndrome and inflammatory disorders

The ability to noninvasively assess the patency of coronary stents would represent a significant advance. We evaluated the safety and ability of two-dimensional coronary MR angiography in imaging stents and suggesting patency. Coronary MR angiography of 26 coronary stents (Palmaz-Schatz) was performed in 16 patients 39 to 73 years of age. Studies were performed between 2 and 4 months after stent placement. All patients were symptom free at the time of imaging. Coronary MR angiography was performed with a commercial 1.5-T MR imager using an electrocardiographically gated pulse sequence with breath-holding. Images were obtained in mid-diastole with and without fat suppression. Image artifacts caused by the metal in the stents were clearly visualized in all 26 stents (100% sensitivity for stent detection). Arterial flow signal was seen in the coronary artery or graft distal to the stent in 25 of 26 cases (96%). All patients, except for the one in which distal flow could not be seen, remained symptom free for >2 years. The distribution of stent locations was as follows: 10 in the right coronary artery (RCA), 10 in the left anterior descending coronary artery (LAD), 2 in the left circumflex coronary artery, and 4 in saphenous vein grafts (SVGs) to RCA. One patient had 2 RCA and 2 LAD stents, one had 3 RCA and 1 LAD stents, one had 3 SVG stents, and two had double RCA stents. Coronary MR angiography is safe for noninvasive imaging of coronary stents, and in the proper clinical setting, it can be used to help suggest patency.     

Cytokine-induced sequential migration of neutrophils through endothelium and epithelium

RATIONALE AND OBJECTIVES: To evaluate different vein graft-coated stent systems in the endovascular treatment of experimental arteriovenous fistulae (AVF) in a canine model. METHODS: Bilateral carotid-to-external jugular vein AVF were created. Two balloon-expandable tantalum stents (Strecker stent), two self-expanding nitinol stents (Strecker stent), and one stainless-steel stent (Wallstent) were coated with autologous vein grafts and placed using a transfemoral approach. Angiography was performed immediately after stent placement and at week 1 and 3, as well as at months 3, 6, and 9. All stents were removed and underwent histologic examination. RESULTS: Occlusion of the AVF succeeded with the Wallstent and both tantalum stents. The nitinol stents were misplaced, maintaining the AVF. One undersized tantalum stent and the Wallstent were occluded after 3 weeks. One nitinol stent was occluded at 3 months, whereas the two remaining stents were patent during the whole observation period. No inflammatory tissue response was seen, and no host-versus-graft reaction was present. CONCLUSIONS: Preparation and implantation of vein graft-coated stents, especially in the case of self-expanding stent systems, is cumbersome. This restricts the common use of such a coating, which shows an excellent biocompatibility. Vein graft-coated stents might be of use in infected endangered vessels.     

Percutaneous coronary angioplasty of radial artery conduits

The higher long-term patency of internal mammary artery grafts has stimulated the search for alternative conduits in order to achieve a complete arterial myocardial revascularization. Percutaneous angioplasty is often the preferred strategy for the treatment of recurrent ischemia in patients who previously underwent bypass surgery, but there is limited experience in the treatment of arterial grafts. We describe two cases of percutaneous treatment of diseased radial artery (RA) grafts. In the first case, two disarticulated stents were deployed through an RA graft: half stent inside the anastomosis to the left anterior descending (LAD) artery, and half stent in the distal LAD artery. Diffuse spasm of the RA graft, resistant to ic nitrates, was successfully reversed after ic calcium antagonists. Absence of restenosis was confirmed two years later. In the second case, after simultaneous catheterization of both the left coronary artery and RA graft, two long stents were implanted in the LAD artery and a final "reversed" kissing-balloon dilation through the stent struts was performed; four months later the patient showed proximal occlusion of the LAD artery and the stenotic RA distal anastomosis was successfully dilated.     

Electron-beam CT in the noninvasive assessment of coronary stent patency

RATIONALE AND OBJECTIVES: Coronary artery stents reduce the rate of restenosis in patients who have undergone balloon angioplasty; therefore, the implantation of coronary stents represents an important method in the treatment of coronary stenoses. The authors' purpose was to investigate the usefulness of electron-beam computed tomography (CT) as a noninvasive means of assessing the patency of coronary artery stents in patients who had undergone balloon angioplasty and stent placement. MATERIALS AND METHODS: Electron-beam CT was used to assess stent patency in 177 patients with 285 stents. Contrast material-enhanced multisection flow studies were performed, and the images were evaluated by three investigators and compared with the findings of coronary angiography. RESULTS: Cine loop evaluations and time-attenuation curve analysis led to the correct diagnosis in 167 (94.3%) patients, as confirmed with coronary angiography. Stenoses had occurred in 18 of the 194 vessels with stents, and 14 of these were detected with electron-beam CT. CONCLUSION: Electron-beam CT appears to be a valuable imaging modality in the noninvasive assessment of stent patency in coronary arteries.     

Analysis of T-cell receptor gene rearrangement in lymph nodes of patients with mycosis fungoides. Prognostic implications

PURPOSE: To evaluate different vein grafts for luminal coating of endovascular stents in normal canine arteries. METHODS: Twenty-four tantalum Strecker stents were coated with either autologous (n = 10), denatured heterologous (n = 11), or denatured homologous vein grafts (n = 3). The carotid artery (n = 11) and the iliac artery (n = 13) were stented using a transfemoral approach. Angiograms were performed at days 0, 7, and 21, and months 3, 6, and 9. All grafts underwent histological examination. RESULTS: Eight of 10 autologous vein grafts showed patency during the whole observation period of 9 months, without histological signs of inflammation. Denatured heterologous vein grafts revealed acute (n = 3), subacute (n = 5), or delayed (n = 3) vessel occlusion. Hyaloid transformation of the vein graft and lympho-plasmacellular formations were seen. Denatured homologous vein grafts showed acute vessel occlusion. Although significant inflammatory tissue response was seen, no host-versus-graft reaction was present. CONCLUSION: Autologous vein graft-coated stents showed good biocompatibility in canine arteries. Preparation was cumbersome and required surgical venae-sectio. Denatured vein grafts, however, were limited by inflammatory reactions.     

Initial experience with venous stents in exertional axillary-subclavian vein thrombosis

PURPOSE: Exertional thrombosis of the axillary and subclavian veins, also known as Paget-Schr?tter syndrome, has been increasingly recognized in recent years as a cause of long-term morbidity. Recent aggressive approaches to treating Paget-Schr?tter syndrome have suggested the association of early failure with residual subclavian vein stenosis. As a result, the use of endoluminal stents has been proposed as an aid to venous percutaneous transluminal angioplasty for this disorder. METHODS: This report outlines the therapy of 11 consecutive patients with Paget-Schr?tter syndrome who were treated at our institution between October, 1992, and December, 1995. Stents were placed when percutaneous transluminal angioplasty was unsuccessful at achieving an adequate residual lumen. RESULTS: Stents were placed after initial thrombolysis in six patients and in late follow-up in two patients. Of the six patients who had stents placed at initial thrombolysis, first-rib resection was eventually performed in four. In two patients first-rib resection was not performed, and stent fracture occurred in both. Late patency was achieved in the stents of six of the eight patients. CONCLUSIONS: Trials to evaluate stents as an adjunct to conventional therapy seem warranted. The use of stents alone without first-rib resection, however, appears to be associated with stent fracture.     

Very distal bypass for salvage of the severely ischemic extremity

Forty-six bypass grafts to tibial arteries distal to the ankle were performed in 35 patients for salvage of extremities threatened by gangrene or nonhealing ulcers (grade III, category 5) or ischemic rest pain (grade II, category 4). Most patients (80%) were diabetic, with severely calcified arteries, whom previously we would have considered as candidates for primary amputation. All reconstructions were performed with autologous saphenous vein. Inflow was from the common femoral artery in 5 (11%), the popliteal artery in 25 (54%), or the mid-tibial arteries in 16 (35%). Life-table analysis was used to calculate primary patency and limb salvage. Results were analyzed according to origin of inflow, outflow, or configuration of the conduit (in situ saphenous vein, n = 29 [63%], reversed saphenous vein, n = 11 [24%], or nonreversed saphenous vein, n = 6 [13%]). Overall cumulative primary graft patency at 2 years for all grafts was 72%, and the cumulative limb salvage rate was 89% for the same interval. No significant differences were seen in comparing grafts originating from the femoral or popliteal level with those arising from the tibial arteries. No significant differences were noted in graft patency or limb salvage among grafts with a posterior tibial, dorsalis pedis, or plantar artery outflow. No significant difference was noted between in situ saphenous vein grafts and reversed saphenous vein grafts. A significant decreased primary patency was noted for grafts performed with nonreversed, translocated saphenous vein. We conclude that bypass grafts to the ankle or foot vessels are beneficial and should be considered for limb salvage in extremities with gangrene, ischemic ulceration, or ischemic rest pain. In our experience, in situ saphenous vein grafts or reversed saphenous vein grafts performed similarly, whereas nonreversed saphenous vein grafts have a poorer prognosis. Vessel wall calcification requires a modification in technique for performance of these grafts but did not affect long-term performance or limb salvage, and thus should not be considered a contraindication to vascular reconstruction. The operative microscope was used in 61% (28 of 46) of these cases and found useful in creating these delicate anastomoses. Additional follow-up is needed to document the long-term results of these very distal reconstructions.     

Metallic stents in malignant biliary obstruction: prospective long-term clinical results

OBJECTIVE: The purpose of this prospective study was to evaluate the long-term clinical efficacy of metallic stents when used as the initial palliative treatment of patients with inoperable malignant biliary obstruction. SUBJECTS AND METHODS: From August 1991 through May 1995, 100 consecutive patients with malignant biliary obstruction were treated with percutaneous placement of metallic stents. The causes of obstruction were bile duct carcinoma (n = 50), pancreatic carcinoma (n = 17), gallbladder carcinoma (n = 6), hepatocellular carcinoma (n = 2), and metastatic lymphadenopathy in the hepatoduodenal ligament (n = 25). We used 123 stents: 64 Gianturco Z stents, 39 Hanaro spiral stents, 16 Wallstents, two tantalum Strecker stents, one Endocoil stent, and one Memotherm nitinol stent. Every 3 months we followed up all patients except those who died. The average length of follow-up was 220 days (range, 4-1125 days). Patient survival and stent patency rates were estimated by life-table analysis. RESULTS: The median length of survival for the entire patient group was 246 days: 25-week and 50-week survival rates were 62% and 25%, respectively. We found no statistically significant difference in the median length of survival between patients with hilar obstruction (256 days) and patients with common bile duct (CBD) obstruction (227 days). Patients with bile duct carcinoma had longer median survival (269 days) than did patients with other conditions (197 days). The overall median length of patency for all stents was 360 days; the 25-week and 50-week patency rates were 81% and 53%, respectively. The stent patency rate at the median length of survival was 71%. The median length of stent patency in patients with hilar obstruction (617 days) was nearly double that of patients with CBD obstruction (324 days). However, the median length of stent patency in patients with bile duct carcinoma showed no statistically significant difference from the median length in patients with other disease. Four patients (4%) died within 1 month after stent placement. Twenty-one patients (21%) developed recurrent jaundice or cholangitis. In order of frequency, the causes of recurrent jaundice were tumor overgrowth, incrustation of bile sludge, duodenal obstruction due to tumor invasion, stent impaction into the bile duct wall, stent malposition, and tumor ingrowth. CONCLUSION: Metallic stents showed a favorable patency rate with regard to patient survival. In patients with hilar obstruction, the clinical efficacy of metallic stents was superior to that in patients with CBD obstruction. We believe that placement of metallic stents is the procedure of choice for palliation of malignant biliary obstruction.     

Benign biliary strictures associated with recurrent pyogenic cholangitis: treatment with expandable metallic stents

OBJECTIVE: The purpose of this study was to determine the long-term effectiveness of expandable metallic stents in benign biliary strictures associated with recurrent pyogenic cholangitis and the differences in primary patency of the various types of stents deployed. SUBJECTS AND METHODS: During a 20-month period, 26 metallic stents (19 Gianturco-Rosch Z stents and seven Strecker stents) were used to treat benign biliary strictures associated with recurrent pyogenic cholangitis in 23 patients (11 men and 12 women; mean age, 42 years; range, 30-78 years). Insertion routes were percutaneous transhepatic biliary drainage tracts for 16 stents, T-tube tracts for seven stents, and retrograde endoscopic routes for three stents. The deployed locations were common hepatic or common bile ducts for 11 stents, right or left hepatic ducts for 10 stents, and segmental ducts for five stents. RESULTS: The initial technical success rate was 100%. Two stents in one patient migrated spontaneously. Primary stent patency for the remaining 24 stents was 34 months (range, 3-58 months). Primary stent patency of the Gianturco-Rosch Z and Strecker stents was 50 and 10 months, respectively (p < .05). Primary stent patency for the intrahepatic and extrahepatic ducts was 50 and 18 months, respectively (p = .05). Primary patency rates for all stents at 6, 12, 24, and 36 months were 92%, 75%, 67%, and 46%, respectively. The causes of stent obstruction were recurrent stone or sludge in eight stents and epithelial hyperplasia in five stents. CONCLUSION: We believe that metallic stent placement is not an effective long-term treatment technique for benign biliary stricture associated with recurrent pyogenic cholangitis.     

Application of rectal stents for palliation of obstructing rectosigmoid cancer

BACKGROUND: The rationale of palliative endoscopic treatment is to avoid a colostomy in patients with advanced disease and limited life expectancy. This study was conducted to evaluate the role of endoscopic stent implantation for palliation of obstructing rectal cancer. METHODS: Overall, 19 patients (aged 47-87 years) with nonresectable or metastatic rectal cancer were treated by stent insertion after laser recanalization or dilation. Three types of stents, i.e., plastic tubes (n = 8), self-expanding mesh stents (n = 6), and endocoil stents (n = 5), were used to maintain luminal patency. RESULTS: Endoscopic stent implantation was successfully performed in all 19 patients. Long-term luminal patency and satisfactory bowel function were achieved in 16 of 19 patients (84%). After a median follow-up of 6 months, eight of the patients have died and eight are still alive without evidence of recurrent obstruction. Dislocation of the endoprosthesis occurred in two of eight plastic tubes and one of five mesh stents. Recurrent obstruction due to tumor ingrowth was only observed in patients treated with self-expanding mesh stents (n = 2). In spite of reinsertion and laser therapy a colostomy was required in three of 19 patients. There was no evidence of treatment failure in five patients who received endocoil stents. None of the patients experienced serious complications related to the endoscopic procedure. CONCLUSIONS: Endoscopic stent implantation seems to be a safe and efficient palliative approach to selected patients with obstructing rectal cancer. Currently, self-expanding coil stents are superior to other devices because of lower risk of dislocation and tumor ingrowth.     

A prospective randomized trial of Teflon versus polyethylene stents for distal malignant biliary obstruction

BACKGROUND AND STUDY AIMS: Clogging of biliary stents continues to be a major clinical problem. Different polymer materials may have different effects on clogging. In vitro studies have shown a direct relation between the frictional coefficient of a polymer and the amount of encrusted material. Teflon appeared to be the best polymer for biliary stents. Two different types of stents made of Teflon have been tested in clinical practice and showed favourable patency rates. However, a randomized trial has never been performed. We compared the patency of an Amsterdam-type polyethylene stent with a Teflon stent in a prospective randomized trial. PATIENTS AND METHODS: Between September 1995 and November 1996, 42 patients received a Teflon stent and 42 patients a polyethylene stent. All patients had a distal malignant biliary stricture without a previous drainage procedure. Diagnoses included carcinoma of the pancreas (n = 76), papilla (n = 1), bile duct (n = 5) and metastases (n = 2). The internal and external diameter (10 Fr), length (9 cm) and stent design (a straight stent with two side flaps and one side hole at each end) were similar for both stents. RESULTS: A reduction in bilirubin of more than 20% within one week was seen in 91% of the patients. Early complication rates were similar in both groups (10%). The median follow-up was 142 days. Stent dysfunction occurred in 28 Teflon and 29 polyethylene stents. The thirty-day mortality was 14% in both groups. Patient survival did not differ significantly between the groups (median survival: Teflon 165 days, polyethylene 140 days). The median stent patency was 83 days for Teflon and 80 days for polyethylene stents, and was not significantly different either. CONCLUSION: Teflon material did not improve patency in biliary stents with an Amsterdam-type design.     

Transfemoral endovascular aortic graft placement

PURPOSE: The purpose of this study was to develop an endovascular system for transfemoral placement of straight aortic grafts and bifurcated aortoiliac grafts. METHODS: Both types of graft consist of barbed, self-expanding stents attached to a woven polyester fabric. Survival studies of straight-graft function were performed in six large mongrel dogs. Digital subtraction fluoroscopic equipment was used to guide insertion and record angiograms at 0, 1, and 3 months. Bifurcated grafts were inserted in an additional eight dogs, four with distal stents and four without. Straight grafts were inserted into six cadaveric aortas (five atherosclerotic and one aneurysmal; age 68.7 + 5.7 years) to assess stent attachment. RESULTS: Angiograms obtained immediately after straight-graft insertion showed placement to be within 4.6 + 1.6 mm of the intended level. Follow-up angiograms at 1 and 3 months showed no migration, no leakage, and patency of all six grafts. After bifurcated graft insertion there were no angiographic signs of perigraft leakage, with or without distal stents. The mean force required to displace straight grafts 10 mm from their original position in cadaveric aortas was 1388 + 127 g. CONCLUSION: These preliminary results show that straight and bifurcated endovascular grafts can be positioned accurately and securely in the abdominal aorta.     

Restenosis of peripheral stents and stent grafts as revealed by intravascular sonography: in vivo comparison with angiography

OBJECTIVE: Our objective was to compare intravascular sonography with digital subtraction angiography (DSA) in the assessment of luminal dimension and morphologic features of endovascular stents and stent grafts. MATERIALS AND METHODS: Thirty-seven pelvic and 24 femoral stents (12 Wall-stents; 27 covered and 22 uncovered nitinol stents) in 50 patients were evaluated 15 +/- 10 months after implantation by DSA and intravascular sonography. The degree of maximum instent restenosis as revealed by DSA and intravascular sonography was compared for each location. Morphologic features of the stents and stenoses were also assessed. RESULTS: Intravascular sonography and DSA correlated well (R2 = .96) in determining in-stent restenosis. In-stent restenosis was underestimated by 13% +/- 6% by DSA compared with intravascular sonography. Differences in determining in-stent restenosis with intravascular sonography and DSA were not associated with severity of stenosis or type of stent. Intravascular sonography revealed incomplete expansion of stents in 21 cases, whereas DSA revealed incomplete expansion of stents in seven cases. The intra- and interobserver variabilities in our study were 4% and 5%, respectively. CONCLUSION: In-stent restenoses are underestimated with DSA. Intravascular sonography is superior to DSA for detection of incomplete stent expansion.     

Negative control elements of the cell cycle in human tumors

OBJECTIVE: To report our experience with metallic self-expanding stents in the palliative care of patients with ureteric obstruction caused by advanced pelvic malignancy. PATIENTS AND METHODS: Seven patients (five men and two women, mean age 72.8 years, range 58-88) with ureteric obstruction caused by advanced pelvic malignancy were evaluated. Self-expanding metallic Memotherm stents (Angiomed, Karlsruhe, Germany) were deployed using an antegrade approach in all patients. Patients were followed for a mean (range) of 9 (4-13) months to assess renal function and survival. RESULTS: All seven patients had good palliation; their quality of life was improved and symptom such as loin pain were ameliorated. Renal function was preserved; the mean serum creatinine level before and after stenting was 636 and 263 mumol/L, respectively). The mean duration of stent patency was 9 months. Of the five patients who subsequently died, only two had recurrent renal failure, presumably caused by stent occlusion. CONCLUSIONS: The use of metallic stents in the palliative care of ureteric obstruction caused by advanced pelvic malignancy is a safe and effective treatment.     

Reconstruction of large veins for nonmalignant venous occlusive disease

To evaluate the effectiveness of venous grafting, we reviewed the management and clinical course of 28 patients (21 males and seven females) who underwent 29 reconstructions of large veins for benign disease. There were 12 patients with superior vena cava (SVC) syndrome, two with subclavian vein thrombosis, and 15 with occlusion of the inferior vena cava (IVC) or iliac veins. One of these patients underwent both IVC and SVC reconstructions. Reconstruction of the SVC was performed with spiral saphenous vein graft (SSVG) in nine patients and expanded polytetrafluoroethylene (ePTFE) in three. All seven straight SSVGs had documented patency at a median of 7 months (2 weeks to 5 years) after reconstruction. Six patients had complete relief of symptoms. Two patients with bifurcated SSVG had early occlusion of one graft limb. Two of the three ePTFE grafts needed early thrombectomy. One graft reoccluded at 6 months and two were patent at 2 and 5 years. The two subclavian vein reconstructions with axillary-jugular ePTFE grafts with an arteriovenous fistula had documented early patency. Both patients had rapid resolution of symptoms. The IVC or iliac vein was reconstructed with ePTFE graft in 11 patients, SSVG in three, and Dacron in one. A femorofemoral arteriovenous fistula was added in eight patients with ePTFE grafts. Seven of the 11 ePTFE grafts had documented patency at the last follow-up (median 9 months; range 2 weeks to 5 years). None of the three SSVGs had documented long-term patency. The one Dacron cavoatrial graft occluded at 3 years. A straight SSVG continues to be our first choice for SVC replacement. Short, large-diameter ePTFE grafts perform the best in the abdomen. Femorocaval or long iliocaval grafts need an arteriovenous fistula to maintain patency. Long-term patency after closure of the fistula is still unknown. Femorocaval grafts with poor venous inflow have limited chance of success. Failed or failing grafts may be salvaged by early thrombectomy. Venous reconstruction to treat selected patients with symptoms with large vein occlusion continues to be a viable option.     

Effect of growth hormone therapy in children with achondroplasia: growth pattern, hypothalamic-pituitary function, and genotype

PURPOSE: To evaluate the success rates of the implantation of stent grafts in the treatment of peripheral aneurysms. MATERIALS AND METHODS: In 13 patients with 15 aneurysms at the common iliac artery (n = 6), external iliac artery (n = 1), hypogastric artery (n = 2), femoral artery (n = 2) or popliteal artery (n = 4), implantation of dacron-covered nitinol stents was performed. The patients were followed up for three to 20 months (mean, 8.8 months) with intravenous digital subtraction angiography, CT or colour-coded Doppler sonography. RESULTS: In all cases, the aneurysm was successfully occluded after stent implantation. In one case with a popliteal aneurysm, kinking of the vessel caused thrombosis of the stent. The stent was successfully reopened. The aneurysm however, had to be surgically treated 9 months later. The primary and secondary patency rates at 6 months were 93% and 100%, respectively. CONCLUSION: The method described might be an alternative therapy to surgery. There are some limitations in respect of treatment of popliteal aneurysms.     

Impact of inflow reconstruction on infrainguinal bypass

PURPOSE: This study assessed whether multisegmental disease that is severe enough to require an inflow procedure adversely affects infrainguinal bypass patency, limb salvage, or patient survival rates. METHODS: The records of 495 patients who underwent 551 infrainguinal bypass grafting procedures were reviewed. Saphenous vein and prosthetic grafts were evaluated separately. Graft patency rates, patient limb salvage rates, and patient survival rates in those grafts that arose from a reconstructed inflow source were compared with those that arose from normal, nonreconstructed inflow sources. When grafts had either hemodynamic failure or occlusion, the cause of failure was identified. RESULTS: Four-year primary patency rates in vein grafts that arose from a reconstructed inflow sources were lower than those in grafts that arose from nonreconstructed inflow sources (41% vs 54%; p = 0.006). Assisted primary patency rates and secondary patency rates, however, were similar (62% vs 74% and 64% vs 77%, respectively). The 4-year primary patency rate (45% vs 55%), assisted primary patency rate (60% vs 60%), and secondary patency rate (60% vs 61%) in prosthetic grafts did not vary based on inflow source. The most common cause of graft failure was inflow failure, except in the vein grafts that did not require an inflow procedure, in which the most common cause of failure was graft failure. Inflow failure occurred in 24% and 22% of the vein and prosthetic grafts with multisegmental disease, respectively, but in only 7% (p < 0.001) and 10% (p < 0.05), respectively, of those that arose from normal nonreconstructed inflow. The presence of an inflow procedure did not affect limb salvage rates or patient survival rates, regardless of graft material. CONCLUSIONS: Long-term patency rates, patient limb salvage rates, and survival rates in patients with a reconstructed inflow source were similar to those of patients with a normal nonreconstructed inflow. A major cause of occlusion is inflow failure, and this occurs in a greater proportion of patients with multisegmental disease. These patients, in particular, may benefit from patient surveillance to screen for progression of their inflow disease and to allow for intervention before infrainguinal graft occlusion.     

New stent technologies

Poor long-term patency of saphenous vein grafts limits the long-term success of the coronary artery bypass operation. If this is to be improved, either measures that increase the patency of saphenous vein grafts or alternative conduits are required. The benefits of using the left internal mammary artery as a pedicled graft to the left anterior descending coronary artery have prompted increasing use of arterial grafts to further improve outcome. Concurrently advances in the understanding of the pathological processes underlying saphenous vein graft occlusion raise the possibility of improving vein graft patency. In this paper we review the problem of vein graft occlusion and possible solutions, the theoretical benefits of arterial grafts and the clinical results associated with their use.     

On a mechanism for isochromatid 17q in a subset of Ph+ chronic myeloid leukemia patients

Considerable advances have been made in reconstructive venous surgery in the past two decades because of an increased recognition of venous disease and because of extensive experimental work. Meaningful evaluation of longterm patency of bypass grafts and midterm patency of stent placement are now available and seem appropriate to provide guidelines. Based on our experience and on the literature, this article highlights the techniques and the respective indications of surgical and endovascular treatment of large vein reconstructions.     

Rapid intraoperative construction of autologous small caliber blood vessels

Autologous pericardium, briefly tanned in glutaraldehyde, is an excellent biomaterial when used in various cardiac procedures, including repair and replacement of heart valves. A generalized lack of calcification and an absence of inflammatory response in these combined experiences has led the authors to consider the use of treated autologous pericardium for the construction of substitute small caliber blood vessels. Rapid, intraoperative construction of a vascular graft from autologous pericardium, briefly treated in 0.62% glutaraldehyde, is accomplished through the use of two concentric, mating helical stents that support a rectangular pattern of tissue into a cylindrical, nonkinking, compliant conduit. A disposable automated assembly tool provides for precise assembly of the tissue and stents. The tools and methods for construction of vascular grafts from nonvascular tissue are known as the Rapidgraft (Ramus Medical Technologies, Santa Barbara, CA). The technique can be used with any suitable tissue. Accelerated fatigue test studies have confirmed that stent supported pericardial grafts are capable of withstanding physiologic pressures and flows beyond 7 equivalent years. Six autologous pericardial grafts measuring 5 mm in diameter by 5.5 cm in length showed 100% patency beyond 5 months in a growing calf carotid artery model. Pathological examination of explanted grafts confirm the presence of a continuous endothelial lined surface, infiltration of the tissue by fibrous connective tissue such that the individual layers of the pericardial vessel wall could not be identified, and there was no inflammatory response. Based on the encouraging results in animal studies, a small multicenter clinical trial has been initiated to evaluate the performance of the Rapidgraft as a replacement conduit for the radial artery in cases in which the radial artery has been harvested as a coronary artery bypass conduit. Results from the radial artery trial will be used as an indication to evaluate the Rapidgraft as a coronary artery substitute. We conclude that the material properties, including the biological origin of a vessel wall, may be significant determinants of graft patency, and that the Rapidgraft may be an answer to the need for small caliber arterial graft with the potential for long-term patency and durability.