Survival in patients undergoing transjugular intrahepatic portosystemic shunt: ePTFE-covered stentgrafts versus bare stents

In patients with liver cirrhosis, implantation of a transjugular intrahepatic shunt (TIPS) leads to reduction of portal pressure, but not of mortality compared with other therapies. The high stenosis rates of conventional bare stents causes high reintervention rates and costs and may be correlated with poor survival. ePTFE-covered stentgrafts provide much improved patency rates, but their impact on survival is unclear. All suitable patients receiving either bare TIPS (419/466) or undergoing implantation of ePTFE endoprostheses (89/100) in several centers in Austria up to 2002 were included in this retrospective analysis. Both patient groups were compared regarding survival with Kaplan-Meier and Cox regression analysis. Unmatched and 1:1-matched survival analyses were performed. Patients undergoing ePTFE stentgraft implantation had significantly higher survival rates in all analyses. The 3-month, 1-year, and 2-year survival rates were 93%, 88%, and 76% for the ePTFE-group and 83%, 73%, and 62% for conventional TIPS patients, respectively. The matched survival analyses validated these findings. The model of the stent, patient age, and Child-Pugh Class (CPC) were independent predictors of survival. In conclusion, patients undergoing ePTFE-endoprosthesis implantation had higher survival rates within 2 years after TIPS-implantation. This may be the result of improved patency rates after correct placement (up to the inferior caval vein [ICV]) of the ePTFE stentgraft. These data should be validated in a prospective series.

Perkutane, radiologisch gesteuerte Vertebroplastie zur Therapie osteoporotischer und tumor�ser Wirbelk�rperl�sionen

Vertebroplasty is a radiological intervention for the augmentation of bone lesions with bone cement. Main indications are the treatment of osteoporotic vertebral body fractures, however also the treatment of tumorous lesions becomes more and more established. The indication for vertebroplasty of tumorous lesions is therapy-refractory pain in symptomatic hemangiomas, metastases and myelomas. By minimal invasive therapy stabilization of vertebral bodies and pain reduction may be achieved.

Contrast Material–enhanced, Moving-Table MR Angiography versus Digital Subtraction Angiography for Surveillance of Peripheral Arterial Bypass Grafts

PURPOSE

To assess the accuracy of moving-table MR angiography (MRA) in the evaluation of peripheral bypass grafts.

MATERIALS AND METHODS

There were 39 patients who had had peripheral bypass graft surgery and then subsequently underwent digital subtraction angiography (DSA) and contrast material-enhanced MRA, which was performed with moving-table software on a 1.0-T system before and during administration of 40 mL gadolinium. For evaluation, every bypass graft was divided into three parts and every leg into 14 segments. Disease severity was scored in four categories (0%-29%, 30%-69%, 70%-99%, 100%). Results were compared with those of the DSA. A total of 147 bypass graft segments and 938 vessel segments were classified.

RESULTS

In 132 of the assessable 147 bypass segments, disease gradings with both methods were congruent; however, 13 stenoses were misinterpreted by MRA for one grade and two additional lesions by two grades, leading to an accuracy in precise stenoses detection of 89.9%. The sensitivity and specificity values in the detection of bypass graft stenoses >69% (grade 3 + 4 lesions) reached 90.0% and 98.3%, respectively. In 821 of 938 vessel segments the accuracy of MRA in stenoses detection reached 87.5%. The sensitivity and specificity values in the detection of grade 3 + 4 lesions were 95.6% and 94.0% for the native vessels, respectively.

CONCLUSION

Moving-table MRA was as accurate in assessing bypass grafts as it was for the native arteries and showed a great accuracy in stenosis detection compared with DSA. Therefore, MRA is a promising modality for bypass graft surveillance and might be a noninvasive alternative to DSA in this regard.

Child-Pugh versus MELD score in predicting survival in patients undergoing transjugular intrahepatic portosystemic shunt

BACKGROUND

In patients undergoing transjugular intrahepatic portosystemic shunt (TIPS), prognostic scores may identify those with a poor prognosis or even those with a clear survival benefit. The Child-Pugh score (CPS) is well established but several drawbacks have led to development of the model of end stage liver disease (MELD).

AIM

The aim of the study was to compare the predictive power of CPS and MELD, to validate the original MELD formula, and to assess the predictive value of the determinants used in the two prognostic scores outside of a study setting.

PATIENTS

A total of 501 patients underwent elective TIPS placement and 475 patients fulfilled the inclusion criteria.

METHODS

Data of all patients undergoing elective TIPS in one university hospital and four community hospitals in Vienna, Austria, between 1991 and 2001, were analysed retrospectively. The main statistical tests were Cox proportional hazards regression model, the log rank test, Kaplan-Meier analysis, and concordance c statistics.

RESULTS

Median follow up was 5.2 years and median survival was 4.6 years. During follow up, 230 patients died, 75 within three months after TIPS placement. In stepwise proportional hazards analyses, independent predictors of death were creatinine level, bilirubin level, age, and refractory ascites. MELD was better in predicting survival in a stepwise Cox model but both scores were equally predictive in c statistics for one month, three month, and one year survival. Renal function was the strongest independent predictor of survival.

CONCLUSIONS

Although MELD was the primary predictor of overall survival in multivariate analysis, c statistics showed that both scores can be used for patients undergoing TIPS with equal accuracy. For assessing prognosis in patients undergoing TIPS implantation, there seems little reason to replace the well established Child-Pugh score.

[Noninvasive vascular diagnosis with magnetic resonance angiography]

Currently contrast medium-enhanced, 3D magnetic resonance angiography enables fast and non-invasive depiction of the arterial vessels in the neck, thorax, abdomen, and limbs, which allows high sensitivity and specificity in the diagnostically evaluation of aneurysms, dissection and arterial stenosis. Intravenous bolus administration of a paramagnetic contrast medium is performed after timing of the bolus arrival time, thus enabling rapid acquisition of 3D datasets with high contrast between vessel lumen and surrounding soft tissue. Thorax and abdomen are examined within one breath-hold, the periphery of the extremities and the supra-aortal vessels can be imagined with longer sequences and even increased spatial resolution. Fast contrast-enhanced 3D magnetic resonance angiography--in combination with flow measurements--carries the potential to replace the additional functional information obtained by conventional digital subtraction angiography.

Permanent transarterial embolization of neuroendocrine metastases of the liver using cyanoacrylate and lipiodol: assessment of mid- and long-term results

OBJECTIVE

The purpose of our study was to assess the results of hepatic artery embolization using N-butyl-2-cyanoacrylate and ethiodized oil for the treatment of small-bowel neuroendocrine metastases to the liver as part of a multimodality protocol for the treatment of liver metastases from neuroendocrine small-bowel tumors.

MATERIALS AND METHODS

Twenty-three patients underwent permanent embolization of the hepatic artery using cyanoacrylate and Lipiodol for treatment of liver metastases after radical resection of small-bowel neuroendocrine tumors. All patients received additional treatment including somatostatin, and most patients received interferon as well. Cumulative survival rates were estimated using the Kaplan-Meier method.

RESULTS

Overall, 75 embolizations (range, 1-10; mean, 3.3) were performed. Median survival time was 69 months, and the estimated cumulative survival rates reached 95.7% and 65.4% for 1 and 5 years, respectively. Two deaths (8.7%) occurred within 1 month of treatment, and one patient experienced a vascular complication at the time of embolization.

CONCLUSION

Permanent embolization of hepatic arteries as part of a multimodality treatment protocol is beneficial in long-term follow-up for patients with metastasized small-bowel neuroendocrine tumors. The use of cyanoacrylate as an embolic agent is safe and effective.

Elective endovascular stent-graft repair of atherosclerotic thoracic aortic aneurysms: clinical results and midterm follow-up

OBJECTIVE

The purpose of this study was to evaluate the clinical and midterm results after endovascular treatment of atherosclerotic thoracic aortic aneurysms.

MATERIALS AND METHODS

Twenty-eight consecutive patients who were 53-82 years old (mean age, 71.6 years) were treated with a commercially available endoprosthesis. Subclavian transposition or bypass surgery was performed before the procedure in eight patients. Size dynamics of the aneurysms were analyzed on the basis of diameter and thrombus volume measurements obtained on three-dimensional CT reconstructions before hospital discharge (n = 22) and at the 1-year (n = 22), 2-year (n = 12), and 3-year (n = 5) follow-ups.

RESULTS

The technical success rate was 100%. There was no 30-day mortality. None of the patients had symptoms due to spinal cord ischemia. The survival rate at 1, 2, and 3 years was 96.1%, 90.9%, and 80.2%, respectively. During the perioperative period, patients presented with leukocytosis (37%), fever (36%), elevated C-reactive protein value (92%), pleural effusion (50%), and periaortic atelectasis (41%). Three early type I endoleaks sealed spontaneously. Three early type II endoleaks persisted over time, and one late type II endoleak was detected. In patients with type II endoleaks, thrombus volume of the aneurysms was constant (n = 2) or increased (n = 2). In patients without endoleaks, mean thrombus volume decreased (-53.2 +/- 56.8 mL, -40%) significantly (p = 0.001) during the first year. There was no significant interval decrease between the 1- and 2-year follow-ups (mean, -2.4 mL, p = 0.92) and between the 2- and 3-year follow-ups (mean, -0.4 mL, p = 0.68).

CONCLUSION

Endovascular treatment of atherosclerotic thoracic aortic aneurysms may result in a substantial reduction of the aneurysm sac in patients without endoleaks.

Elective and emergent endovascular treatment of subclavian artery aneurysms and injuries

PURPOSE

To demonstrate our short and long-term results after transbrachial treatment of subclavian artery aneurysms and injuries with stent-grafts in elective and emergency settings.

METHODS

Ten of 12 consecutive patients (6 men; mean age 63.8 years, range 38-80) were treated electively with commercially prepared endografts delivered via a transbrachial access to repair a subclavian artery aneurysm (n=3) or an injury from a misplaced central venous catheter (n=7). Two patients required emergency treatment for a ruptured atherosclerotic aneurysm in one and an unintentional arterial puncture during placement of a central venous access in the other. Stent-graft patency during follow-up was assessed by physical examination with comparison of brachial blood pressures in all patients; computed tomography angiography (CTA) was performed in available patients.

RESULTS

Successful deployment of stent-grafts with sealing of the lesion was achieved in all cases. There were 2 (17%) procedural complications. One patient developed an access-site hematoma that required surgical revision. The second patient, who had a right subclavian injury, suffered an embolic cerebral infarction. The primary stent-graft patency during follow-up (mean 11.6 months) was 100%. CTA examinations in 7 patients at a mean 18 months showed strut dislocation at the thoracic outlet without luminal narrowing in 1 patient. A 50% intraluminal narrowing due to compression between the clavicle and the first rib occurred in another patient. Six patients with a mean follow-up of 23 months (range 0.3-4.5 years) are still alive with patent stent-grafts.

CONCLUSIONS

Endovascular stent-graft treatment of subclavian artery aneurysms and injuries is a less invasive alternative to surgical repair. Long-term results must still be confirmed in further studies.

Endovascular stent-graft repair of complicated penetrating atherosclerotic ulcers of the descending thoracic aorta

OBJECTIVE

To report our initial experience with endovascular stent-graft repair of complicated penetrating atherosclerotic ulcers as an alternative to surgery in patients with increased risk of perioperative morbidity and mortality.

METHOD

During a 2-year period, eight patients with complicated penetrating atherosclerotic ulcers of the descending thoracic aorta were treated with the Gore Excluder stent-graft. Patients (mean age, 70.6 years) presented with two to five comorbid conditions causing an increased risk for surgical repair. In addition to painful events, three patients presented with severe hemoptysis, one patient with shortness of breath, and one patient with dysphagia. All patients underwent emergency computed tomography, and diagnosis of contained rupture was confirmed in five patients. Computed tomographic findings included one to three penetrating ulcers per patient (n = 4), pseudoaneurysms (n = 5), additional intramural hematomas (n = 4), mediastinal bleeding (n = 2), and hematothoraces (n = 4). Through an iliac or femoral access site, a total of 11 stent-grafts were implanted under general (n = 5), epidural (n = 2), or spinal (n = 1) anesthesia.

RESULTS

Deployment of stent-grafts was successful in all patients, and all sites of hemorrhage were sealed. The intramural hematoma resolved completely in three cases, and two pseudoaneurysms decreased in size. Intentional occlusion of the origin of left subclavian artery with the stent-graft in one patient was tolerated without left arm or cerebral symptoms. One patient experienced permanent paraplegia immediately after endovascular repair. There were no deaths during the hospital stay (range, 7-35 days; mean, 14.5 days). One patient was lost to follow-up after hospital discharge. The clinical observation period for the remaining seven patients was 38 to 99 weeks (mean, 60 weeks).

CONCLUSIONS

Endovascular stent-graft repair in complicated penetrating atherosclerotic ulcers is an alternative therapeutic option to conventional thoracotomy, especially in patients at high risk of increased morbidity and mortality perioperatively and postoperatively.

Malignant biliary obstruction: treatment with ePTFE-FEP- covered endoprostheses initial technical and clinical experiences in a multicenter trial

PURPOSE

To determine and present the initial technical and clinical results of using an expanded polytetrafluoroethylene-fluorinated ethylene propylene (ePTFE-FEP)-covered biliary endoprosthesis to treat malignant biliary obstruction.

MATERIALS AND METHODS

This prospective nonrandomized study included 42 patients with malignant obstruction of the common bile duct, common hepatic duct, and hilar confluence. Unilateral (n = 38) or bilateral (n = 4) bile duct drainage was performed by using fully covered endoprostheses with anchoring fins. To avoid branch duct blockage, endoprostheses with drainage holes at the proximal end were available. Procedure- and device-related complications were recorded. Patient survival and stent patency rates were calculated with Kaplan-Meier survival analysis. Mean follow-up bilirubin and alkaline phosphatase levels were calculated, and differences in means were evaluated with a paired t test.

RESULTS

Successful deployment, correct positioning, and patency of the device were achieved in all patients. Procedure-related complications occurred in two (5%) patients. Thirty-day mortality rate was 20% (eight of 41 patients), and median survival time was 146 days. Laboratory values decreased significantly after the procedure (P <.001). Recurrent obstructive jaundice occurred in six (15%) patients. Primary patency rates at 3, 6, and 12 months were 90%, 76%, and 76%, respectively. Calculation of the composite end point of death or obstruction revealed a median patency duration of 138 days. No endoprosthesis migration was observed. Branch duct obstruction was observed in four (10%) patients. Postmortem examination of one stent revealed a widely patent endoprosthesis with intact covering.

CONCLUSION

Initial results of percutaneous treatment of malignant biliary obstructions with fully covered ePTFE-FEP endoprostheses suggest that they are safe and potentially clinically effective.

ePTFE-covered stent-grafts for revision of obstructed transjugular intrahepatic portosystemic shunt

PURPOSE

To determine whether transjugular intrahepatic portosystemic shunt (TIPS) revisions with the Hemobahn stent-graft or the Viatorr endoprosthesis increase secondary patency rates.

METHODS

Between 1998 and June 1999, Hemobahn endoprostheses (W.L. Gore, Flagstaff, AZ, USA) were used for the revision of obstructed TIPS in seven patients, 51-67 years of age (mean 59 years). From June 1999 to 2000, the Viatorr endoprosthesis (W.L. Gore, Flagstaff, AZ, USA) was used for revision of obstructed TIPS in nine patients, 33-64 years of age (mean 49 years). Follow-up included duplex ultrasound, clinical assessment and venous portography.

RESULTS

The technical success rate of TIPS revision with the Hemobahn stent-graft was 100%. The pressure gradient decreased from a mean of 20 mmHg to 10 mmHg. The mean follow-up was 407 days (range 81-868 days). In two patients TIPS occlusion occurred at 62 and 529 days after stent-graft placement, respectively; in another two patients outflow tract stenosis occurred at 275 and 393 days, respectively. The technical success rate of TIPS revision with the Viatorr endoprosthesis was also 100%. The pressure gradient decreased from a mean of 27 mmHg to 11 mmHg. At a mean follow-up of 201 days (range 9-426 days), all Viatorr endoprostheses are still patent without in-graft stenosis, but angioplasty was required in two patients to treat a portosystemic pressure gradient > 15 mmHg. Four of the nine patients in the Viatorr group suffered from new encephalopathy after TIPS revision.

CONCLUSION

The Viatorr endoprosthesis yielded optimal results with 100% in-graft patency rates at follow-up but had a high incidence of new encephalopathy, whereas the use of Hemobahn stent-graft for TIPS revision did not appear to improve the secondary patency rates in our series.

Predictors of long-term results after treatment of iliac artery obliteration by transluminal angioplasty and stent deployment

PURPOSE

To investigate initial and long-term success rate after percutaneous treatment of iliac artery occlusion with angioplasty and stent deployment. To investigate the influence of vascular comorbidity, lesion length, stent placement and lesion coverage as possible predictors of outcome.

METHODS

Between January 1994 and December 1999, 80 iliac recanalizations were performed on 78 patients, median age 61.1 +/- 11.5 (SD) years. All patients were followed up by clinical examinations, duplex ultrasound and intravenous digital subtraction angiography. Mean follow-up time was 2.0 +/- 1.53 (SD) years. Multivariate Cox regression analysis was used to determine the influence of cofactors on patency.

RESULTS

One, 2 and 4 years after recanalization, primary patency was 78.1%, 74.5% and 64.0%; secondary patency was 88.8%, 88.8% and 77.9%, respectively. Patients with shorter occlusions, complete lesion coverage and patent ipsilateral femoral arteries had significantly longer patency rates. Complications included inguinal hematoma (n=1), technical failure (n=3) aortic dissection (n=1), embolic occlusions (n=7), gluteal claudication (n=1) and genital necrosis after subsequent urethral surgery in one patient with contralateral occlusion and ipsilateral overstenting of the internal iliac artery with subsequent stenosis. Complications were of permanent clinical significance in seven of 78 (9%) of the patients. In 17 (22%) cases, percutaneous reintervention was performed with angioplasty in the stent (n=16) or deployment of a new stent (n=1).

CONCLUSION

Endoluminal stent placement has its place in an interdisciplinary therapeutic approach as a viable therapeutic alternative to major transabdominal bypass surgery and can be performed with comparable complication rates. Patients with short occlusions, patent femoral arteries, and stents covering the entire occlusion have significant longer patency.

Combined surgical and endovascular treatment of acute aortic dissection type A: preliminary results

BACKGROUND

The established treatment modality of acute Stanford type A dissection includes repair of the ascending aorta and various portions of the aortic arch, whereas the descending aorta is left untreated. We report a simultaneous approach of open repair of the ascending aorta with transluminal stent grafting of the descending aorta to minimize the consequences of an untreated descending aorta.

METHODS

From April 2001 to February 2002, 8 consecutive patients (3 women [37.5%] and 5 men [62.5%]) with a mean age of 55.7 years (range, 45 to 70 years) were intended to be treated with the combined method of surgical repair of the ascending aorta and transluminal stent grafting into the descending aorta during the period of deep hypothermic circulatory arrest. Circulatory arrest time ranged between 30 and 67 minutes (average, 38.8 minutes). Specially designed Talent stent grafts (32 to 40 mm in diameter, length 13 cm) were inserted under direct vision and deployed with the proximal end at the origin of the left subclavian artery.

RESULTS

Intraoperative stent graft placement was successful in 7 patients (87.5%). Because of severe kinking of the distal arch, stent insertion failed in 1 patient (12.5%). One patient with a history of preoperative stroke in the middle cerebral artery died because of intracerebral bleeding on postoperative day 2, resulting in an in-hospital mortality of 12.5%. Mean intensive care unit stay was 6.4 days (range, 2 to 21 days) and overall hospital stay was 18.2 days (range, 7 to 33 days). Completion computed tomographic scans revealed complete thrombosis of the false lumen in 2 patients and partial thrombosis in 4 patients. Follow-up was complete and ranged from 1 to 9 months (mean, 5.4 months).

CONCLUSIONS

This preliminary study shows that combined surgical and endovascular treatment of acute type A dissection is feasible, and at least partial thrombosis of the false lumen can be achieved, potentially minimizing the risk of further dilatation or rupture. Additionally, the stent graft expands the otherwise sickle-shaped true lumen, thereby ameliorating distal aortic perfusion. Long-term results are warranted to demonstrate the effectiveness of this new combined treatment modality.

Biocompatibility and performance of the Wallstent and the Wallgraft, Jostent, and Hemobahn stent-grafts in a sheep model

PURPOSE

Three recently developed stent-grafts and the Wallstent were compared directly in an ovine animal model with regard to performance and biocompatibility.

MATERIALS AND METHODS

Three stent-grafts, the Hemobahn (polytetrafluoroethylene [ePTFE]/nitinol), Wallgraft (polyester/Ni-Co-Ti-steel alloy), and Jostent peripheral stent-graft (balloon-expandable ePTFE/stainless steel), and the Wallstent (Ni-Co-Ti-steel alloy), were implanted in sheep iliac arteries (one type of each stent or stent-graft per animal, n = 8). Pre- and postimplantation luminal diameters were measured for each prosthesis and implantation site. Angiography, intravascular ultrasonography (IVUS), and histomorphometric, histologic, and scanning electron microscopic analyses were performed at 3 months.

RESULTS

Early lumen gain, late lumen loss, and patent vessel diameter at angiography were not significantly different. Two stent-grafts had significantly more neointima formation (Hemobahn, 9.88 mm(2) +/- 0.94; Wallgraft, 14.98 mm(2) +/- 0.90) than the other stent-graft (Jostent, 6.52 mm(2) +/- 0.46) and the Wallstent (5.24 mm(2) +/- 0.62; P <.01). Patent lumen area was not significantly different (Hemobahn, 42.57 mm(2) +/- 1.41; Jostent, 39.76 mm(2) +/- 2.04; Wallgraft, 40.22 mm(2) +/- 1.04; Wallstent, 41.64 mm(2) +/- 1.59; P =.57). The Hemobahn had significantly more inflammatory reaction (inflammation score of 0.83 +/- 0.03) than the Jostent (0.58 +/- 0.03), Wallgraft (0.55 +/- 0.04), or Wallstent (0.16 +/- 0.01). Angiography and IVUS demonstrated absence of anastomotic neointima formation. Endothelialization was incomplete and immature for all prostheses.

CONCLUSIONS

The stent-grafts caused a greater degree of neointima formation and inflammatory vessel wall reaction than the bare stent. However, these changes did not interfere with patent lumen areas and occurred in the absence of excessive anastomotic neointima formation.

MR angiography vs CT angiography in the follow-up of nitinol stent grafts in endoluminally treated aortic aneurysms

Our objective was to evaluate the accuracy of contrast-enhanced 3D MR angiography (MRA) in the follow-up of patients with endoluminally treated aortic aneurysms and correlate these findings with uni- or biphasic CT angiography (CTA). Forty MR angiograms in 32 patients with implanted aortic nitinol stent grafts were compared to CTA. Twenty-two MR examinations were correlated with arterial-phase CTA (uniphasic), and 18 MR examinations were correlated with biphasic CTA. Uniphasic CTA demonstrated three type-1/type-3 endoleaks and four reperfusion (type-2) endoleaks. In addition, MRA depicted two type-2 reperfusion endoleaks that were missed by CTA. Using biphasic CTA, two type-1/type-3 endoleaks and three reperfusion (type-2) endoleaks were detected; of those, delayed scanning detected three reperfusion (type-2) endoleaks missed during arterial-phase CTA. In addition to the findings by CTA, MRA depicted another type-2 reperfusion endoleak. Magnetic resonance angiography is at least as sensitive as uni- or biphasic CTA for detecting endoleaks and may consequently offer advantages in patients with contraindications to iodinated contrast agents.

Imaging of aortic stent-grafts and endoleaks

Although the technical success of stent-graft implantation is established and relatively safe, data on the long-term safety and efficacy of endovascular repair are just emerging. Because several late complications of aortic stent-graft placement have been observed, life-long follow-up remains essential. Imaging methods form an integral part of every stage of endovascular aortic aneurysm repair. The current imaging strategy should include initial plain films, CT angiography, and color-coded Duplex sonography. Plain films are an excellent means to detect migration, angulation, kinking, and structural changes of the stent mesh, including material fatigue, at follow-up. Helical CT angiography is considered a potentially revolutionary method for the noninvasive complete postprocedural assessment of aortic sten-grafting. Current data justify the use of biphasic C angiography as the postprocedural imaging technique of choice in most patients [118]. Ultrasound offers the advantages of low cost and lack of radiation exposure. High-quality ultrasound reliably excludes endoleaks in patients after stent-grafting of AAAs. There is a substantial variability, however, in measuring the diameter of aneurysm sacs; thus, confirmation using an alternative study is prudent in cases that demonstrate a significant change in size during follow-up. MR angiography serves as an attractive alternative to CT angiography in patients with impaired renal function or known allergic reaction to iodinated contrast media. With current techniques, the visualization of aortic stent-grafts (with the exception of stainless-steel-based devices) is sufficient with MR angiography. There is evidence that MR imaging is superior to CT angiography in detecting small type 2 endoleaks or for excluding retrograde perfusion in patients with suspected endotension. The role of diagnostic catheter angiography is limited to assessment of vascular pathways in equivocal cases or for suspected endotension. Currently, a consensus view about postprocedural management after aortic stent-graft implantation is lacking. The authors propose performing a baseline CT angiography at discharge and a biphasic CT angiography and Duplex ultrasound scan at three months. In patients with no evidence of an endoleak, CT angiography, plain film and Duplex sonography (abdomen) should be repeated every year after endovascular repair. If an endoleak is present at follow-up, immediate appropriate treatment should be initiated.

Inhibition of neointimal formation after stent placement with adenovirus-mediated gene transfer of I kappa B alpha in the hypercholesterolemic rabbit model: initial results

PURPOSE

To evaluate the feasibility and efficacy of the local application of a replication-defective adenovirus construct for the expression of the antiinflammatory protein I kappa B alpha, inhibitor of nuclear factor kappa B (NF-kappa B), to reduce neointimal formation after stent placement.

MATERIALS AND METHODS

Nitinol stents were implanted in the iliac arteries of hypercholesterolemic rabbits, followed by balloon dilation (30 seconds at 6 atm). Local adenovirus-mediated transfer of I kappa B alpha (3 mL of 10(9) plaque-forming units per milliliter at 6 atm) was performed and compared with three control groups: stent alone, stent plus local delivery of phosphate-buffered saline (PBS) (3 mL at 6 atm), and stent plus local delivery of control adenovirus coding for green fluorescent protein (GFP) (3 mL of 10(9) plaque-forming units per milliliter at 6 atm). A multichannel balloon was used for local drug delivery and balloon dilation. Animals were sacrificed 1 or 4 weeks after treatment. Effective transfection was demonstrated with immunofluorescence staining. Angiographic patency and luminal diameter were evaluated at quantitative angiography. Luminal and neointimal areas were measured on surface-stained ground sections with methylmethacrylate embedding and the cutting-grinding technique.

RESULTS

All vessels with stents were patent at angiography. Neointimal area was negligible in all groups 1 week after stent placement (range, 0.42-0.52 mm(2); P =.44; analysis of variance). Neointimal formation was demonstrated in all groups 4 weeks after implantation but was significantly reduced with I kappa B alpha treatment compared with treatment with stent alone (by 22%, from 2.80 mm(2) +/- 0.20 to 2.28 mm(2) +/- 0.14, P =.05), stent plus PBS (by 43%, from 3.26 mm(2) +/- 0.25 to 2.28 mm(2) +/- 0.14, P =.005), and stent plus GFP (by 53%, from 2.32 mm(2) +/- 0.19 to 1.51 mm(2) +/- 0.08, P <.005).

CONCLUSION

Local adenovirus-mediated I kappa B alpha gene transfer has the potential to reduce intimal hyperplasia after stent placement.

Endovascular placement of a nitinol-ePTFE stent-graft for abdominal aortic aneurysms: initial and midterm results

PURPOSE

Because first-generation stent-grafts did not meet initial expectations, a recently designed nitinol-expanded polytetrafluoroethylene (ePTFE) stent-graft was tested for treatment of abdominal aortic aneurysms (AAAs) in a prospective clinical study. The primary study endpoints were technical success and safety.

MATERIALS AND METHODS

A nitinol-ePTFE self-expandable stent-graft (Excluder) was used to treat 72 patients with AAAs. The median follow-up period was 21.5 months +/- 13 (range, 1-46 mo).

RESULTS

Primary technical success in accurate placement of the device was achieved in 70 of 72 patients (97%). Complete exclusion of the aneurysm from arterial flow was achieved in 57 of 72 patients (79.2%). Three type I leaks were observed during implantation and were immediately corrected with a proximal cuff prosthesis in two patients. Fourteen of 72 patients (19.4%) had a type II leak. Major complications were observed in three patients (4.1%), including one death in the early postinterventional period (one of 72, 1.4%). At 3 months, aneurysms were excluded in 70 of 71 patients (98.6%), and at 12 months, aneurysms were occluded in 29 of 30 patients (96.7%). The maximum diameter of the aneurysm decreased from 55 mm +/- 11 (median +/- SD) before intervention to 53 mm +/- 13 at 6 and 12 months. None of the patients showed aneurysm growth.

CONCLUSION

This newly designed stent-graft proved to be effective and safe for treatment of AAAs.

MRA of the lower extremities in patients with pulmonary embolism using a blood pool contrast agent: initial experience

PURPOSE

To evaluate the feasibility of blood pool contrast-enhanced magnetic resonance angiography (MRA) to visualize the arterial and venous vessel tree and to detect deep venous thrombosis (DVT) of the lower extremities.

MATERIALS AND METHODS

Nine consecutive patients with pulmonary embolism (mean age = 46 +/- 9) were randomized to various doses of NC100150 (between 0.75 and 6 mg of Fe/kg of body weight). A T1-weighted (T1W) 3D gradient recalled echo (GRE) sequence (TE = 2.0 msec, TR = 5.0 msec) was used. Two observers blinded to the dose of contrast agent assessed image quality, contrast attenuation, and appearance of thrombi.

RESULTS

Qualitative assessment of overall MRA image quality and semiquantitative vessel scoring revealed good to excellent delineation of venous and arterial vessel segments independent of the dose of NC100150. However, quantitative region of interest analysis revealed a significantly higher signal-to-noise ratio (SNR) in the high-dose group than in the mid- and low-dose groups of NC100150 (P < 0.01). Between dose groups, the SNR was independent of vessel type (artery or vein) and vessel segment localization (proximal or distal). All seven venous thrombi (mean length = 7.2 +/- 0.95 cm) were characterized by a very low signal intensity (SI), which was only 16.6 +/- 7% of the SI in adjacent venous segments (P < 0.0001).

CONCLUSION

High-quality MR angiograms of the lower extremities can be obtained using low concentrations of NC100150 in combination with a strong T1W 3D GRE sequence. The obvious delineation of venous thrombi suggests that this technique may be potentially used as a noninvasive "one-stop shopping" tool in the evaluation of thromboembolic disease.

Activation of nuclear factor-kappa B significantly contributes to lumen loss in a rabbit iliac artery balloon angioplasty model

BACKGROUND

To investigate the contribution of inflammation to postangioplasty lumen loss, we used an adenoviral gene therapy approach to inhibit the central inflammatory mediator nuclear factor-kappaB (NF-kappaB) by overexpression of its natural inhibitor, IkappaBalpha.

METHODS AND RESULTS

The adenovirus carrying human IkappaBalpha was applied immediately after balloon dilatation by a double-balloon catheter in a rabbit iliac artery restenosis model. Immunohistochemistry of IkappaBalpha revealed that mainly smooth muscle cells of the media but also cells of the adventitia were transduced and expressed the transgene IkappaB alpha for >/= 8 days. At this time point, intercellular adhesion molecule-1 (30%) and monocyte chemotactic protein-1 (50%) expression, as well as recruitment of macrophages into the wounded area (90%), were significantly reduced in IkappaB alpha-treated vessels. In addition, expression of inhibitor of apoptosis proteins was reduced and the percentage of apoptotic cells was increased compared with control-treated contralateral vessels. Animals killed 5 weeks after treatment exhibited a significantly reduced degree of lumen narrowing (P<0.02) on the side treated with adenovirus IkappaBalpha. The lumen gain of approximately 40% was due to positive remodeling.

CONCLUSIONS

From these data, we conclude that balloon angioplasty-induced activation of NF-kappaB contributes to lumen loss likely via induction of an inflammatory response and a decrease in the rate of apoptosis. These data show for the first time that inflammation mediated by NF-kappaB is involved in postangioplasty lumen narrowing. Specific and more potent inhibitors of NF-kappaB might therefore be a useful therapeutic measure to improve clinical outcome after balloon dilatation.

Imaging features of iliopsoas bursitis

The aim of this study was firstly to describe the spectrum of imaging findings seen in iliopsoas bursitis, and secondly to compare cross-sectional imaging techniques in the demonstration of the extent, size and appearance of the iliopsoas bursitis as referenced by surgery. Imaging studies of 18 patients (13 women, 5 men; mean age 53 years) with surgically proven iliopsoas bursitis were reviewed. All patients received conventional radiographs of the pelvis and hip, US and MR imaging of the hip. The CT was performed in 5 of the 18 patients. Ultrasound, CT and MR all demonstrated enlarged iliopsoas bursae. The bursal wall was thin and well defined in 83% and thickened in 17% of all cases. The two cases with septations on US were not seen by CT and MRI. A communication between the bursa and the hip joint was seen, and surgically verified, in all 18 patients by MR imaging, whereas US and CT failed to demonstrate it in 44 and 40% of the cases, respectively. Hip joint effusion was seen and verified by surgery in 16 patients by MRI, whereas CT (4 of 5) and US ( n=12) underestimated the number. The overall size of the bursa corresponded best between MRI and surgery, whereas CT and US tended to underestimate the size. Contrast enhancement of the bursal wall was seen in all cases. The imaging characteristics of iliopsoas bursitis are a well-defined, thin-walled cystic mass with a communication to the hip joint and peripheral contrast enhancement. The most accurate way to assess iliopsoas bursitis is with MR imaging; thus, it should be used for accurate therapy planning and follow-up studies. In order to initially prove an iliopsoas bursitis, US is the most cost-effective, easy-to-perform and fast alternative.