PTA Versus Carbofilm-Coated Stents in Infrapopliteal Arteries: Pilot Study

PURPOSE

To determine the primary success and short-term patency of stent application as a primary treatment modality for high-grade lesions of the infrapopliteal arteries compared with treatment with percutaneous transluminal angioplasty (PTA) in critical limb ischemia in a randomized prospective study.

METHODS

Endovascular therapy was performed on 95 lesions in 51 patients (mean age 72.0 years, range 47-80 years) who presented clinically with Fontaine stages III and IV. One patient underwent treatment in both limbs. After angiographic lesion identification, patients were randomized for treatment by PTA (53 lesions in 27 patients) or stent application (42 lesions in 24 patients). Follow-up by clinical investigation and conventional angiography or spiral CT angiography was performed in 37 patients (57 lesions) 6 to 12 months after the procedure, or when clinically indicated. Evaluation was performed by two observers, double-blinded, with thresholds for lesion restenosis of 50% and 70%. Statistical evaluation was performed on a lesion basis by Kaplan-Meier estimated probability rates, and log-rank and Wilcoxon tests. The primary endpoint was the angiographic patency rate of treated lesions.

RESULTS

The inter-reader agreement was high (kappa = 0.82). For the stent group the cumulative primary patency at 6 months was 83.7% at the 70% restenosis threshold, and 79.7% at the 50% restenosis threshold. For PTA, the primary patency at 6 months was 61.1% at the 70% restenosis threshold and 45.6% at the 50% restenosis threshold. Both results were statistically significant (p < 0.05).

CONCLUSION

Infrapopliteal stent application is an effective treatment modality for high-grade lesions in chronic critical limb ischemia. Compared with PTA, higher patency rates can be expected after 6 months.

Successful Type II Endoleak Closure by Subclavian-to-Carotid Artery Transposition After Stent-Graft Placement of a Distal Aortic Arch Aneurysm

Endovascular stent-graft placement has become a safe and effective treatment modality for various diseases of the distal aortic arch as well as of the descending aorta. However, its effectiveness may be limited by various kinds of endoleaks resulting in persistent or recurrent perfusion of the aneurysm sac. Subsequently, systemic pressurization leads to expansion of the aneurysm sac, exposing the patient to a recurrent risk of aneurysm rupture. We report on the case of a 57-year-old male who underwent emergency stent-graft placement in March 2001 due to a contained rupture of a distal aortic arch aneurysm involving the origin of the left subclavian artery. Due to the emergency condition, a subclavian-to-carotid artery transposition had not been performed prior to stent-graft placement. During follow-up the patient developed a type II endoleak originating from the left subclavian artery with consecutive enlargement of the aneurysm sac. The endoleak was successfully treated by subclavian-to-carotid artery transposition.

PTA versus Stent bei Stenosen der A. femoralis und A. poplitea: Ergebnisse einer prospektiv randomisierten Multizenterstudie (REFSA)

PURPOSE

To evaluate whether stent placement is superior to percutaneous transluminal angioplasty (PTA) in the treatment of chronic symptoms in short femoropopliteal arterial stenoses.

MATERIALS AND METHODS

One hundred twenty-four limbs in 116 patients, who ranged in age from 39 to 87 years (mean age, 67 years), were randomized to PTA (n = 53) versus PTA followed by implantation of long-medium Palmaz-Stents (n = 71). Inclusion criteria were intermittent claudication or chronic critical limb ischemia, short stenosis or occlusion (lesion length < or = 5 cm), and at least one patent run-off vessel at angiography. The follow-up included clinical assessment, measurement of ankle/brachial index (ABI), color duplex ultrasound, and/or angiography at 6, 12 and 24 months. Angiographic follow-up between 12 and 36 months was available in 54 limbs (45 %).

RESULTS

Initial technical success was achieved in 50 of 53 limbs (94.4 %) in the PTA group versus 70 of 71 limbs (98.6 %) in the stent group. Overall, major complications occurred in 9.5 % (n = 11), with n = 4 in the PTA group compared to n = 7 in the stent group. No difference was found between the groups of treatment: clinical success at 1 and 2 years was 80.5 and 77.1 % in the PTA group versus 78.1 and 71.0 % in the stent group. The cumulative 1-year and 2-year angiographic primary patency rates were 66.1 and 49.1 % in the stent group versus 76.1 and 66.1 % in the PTA group. The secondary 1-year and 2-year angiographic patency rates were 88.5 and 53.3 % in the stent group versus 82.7 % and 76.2 % in the PTA group.

CONCLUSION

The primary success rate was slightly higher after stent placement than after PTA. However, the angiographic, clinical and hemodynamic success after 1 and 2 years tends to be slightly better for PTA.

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.

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.

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.

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.

[Interventions in infrainguinal bypass grafts]

The long-term success of infrainguinal bypass grafts depends on meticulous surgical technique and a periodic program of postoperative surveillance. Duplex scanning is the method of choice for the detection of stenotic lesions that threaten graft patency. As an alternative to surgery, PTA is gaining increasing acceptance for the treatment of non-recurrent, short, and single stenotic lesions, despite somewhat controversial opinions. The initial technical success rates for PTA were reported to be up to 100 %, and a 5-year primary assisted patency rate of up to 65 % has been achieved. Some authors favorize intra-arterial infusion of fibrinolytic agents for the treatment of bypass graft occlusion with technical success rates of up to 92 %. In addition to a reduced trauma compared to surgical thrombectomy, of the venous wall the advantage of thrombolytic therapy is clot lysis in run-off vessels, and uncovering of the stenotic lesions. This stenosis may then be treated by an endovascular or surgical approach.

Creation of transjugular intrahepatic portosystemic shunts with stent-grafts: initial experiences with a polytetrafluoroethylene-covered nitinol endoprosthesis

PURPOSE

To evaluate the safety and performance of a recently developed expanded polytetrafluoroethylene (ePTFE)-covered nitinol stent-graft to create transjugular intrahepatic portosystemic shunt (TIPS) in patients with portal hypertension and related complications.

MATERIALS AND METHODS

The ePTFE-covered nitinol stent-graft was used to create TIPS in 16 patients with recurrent variceal bleeding (n = 13) or refractory ascites (n = 3). Follow-up was performed with duplex ultrasonography, clinical assessment, and venography at 6 months. Technical success and portosystemic pressure gradients (PPGs) before and after stent-graft implantation and at follow-up were assessed. Two patients died during follow-up. Histopathologic follow-up data were available for one patient at autopsy and for the other after liver transplantation.

RESULTS

The implantation technical success rate was 100%. Mean (+/- SD) PPG was reduced from 24 mm Hg +/- 5 to 9 mm Hg +/- 2. Histopathologic analysis of the explanted endoprostheses revealed no inflammatory response or neointima formation. The venographic follow-up data available for 10 patients demonstrated 100% in-graft patency (mean follow-up, 289 days +/- 26). Revisions with implantation of a new ePTFE-covered nitinol stent-graft or another commercially available stent in 10 patients were necessary because of hepatic vein stenosis above the grafted portion and/or relative diameter mismatch causing TIPS dysfunction.

CONCLUSION

The ePTFE-covered nitinol stent-graft was used successfully to create TIPS and has the potential to prolong TIPS patency upon complete coverage to the hepatocaval junction.

Internal iliac artery embolization before endovascular repair of abdominal aortic aneurysms: frequency, efficacy, and clinical results

OBJECTIVE

The aim of our study was to assess the frequency, efficacy, and incidence of adverse effects of internal iliac artery embolization.

MATERIALS AND METHODS

Of 343 patients examined for stent-graft repair, 147 were suitable for endovascular treatment. Fifty-five patients underwent preprocedural embolization of the internal iliac artery either unilaterally (46 patients) or bilaterally (nine patients). Successful embolization was assessed angiographically and with helical CT follow-up examinations. Colonic ischemia was ruled out clinically or colonoscopically. Buttock claudication, and sexual dysfunction in men, were evaluated through a questionnaire.

RESULTS

Embolization of the internal iliac artery increased by 16% the percentage of patients for whom endovascular repair was suitable. After successful embolization in all patients, routine CT follow-up examinations after a mean time of 16.7 months showed no evidence of endoleaks related to retrograde perfusion via embolized internal iliac arteries. Nevertheless, in all patients who had undergone embolization, a primary endoleak was detected in 43.4% at the first postoperative CT examination. None of our patients had evidence of colonic ischemia. Clinical follow-up data of 46 patients were available. Of these patients, mild to severe new onset buttock claudication was found in 13 (36.1%) of 36 patients with unilateral, and in eight (80%) of 10 patients with bilateral, internal iliac artery embolization (p = 0.03). Five (25%) of 20 men had an erectile dysfunction after the procedure.

CONCLUSION

Embolization of the internal iliac artery is a safe and efficient procedure that increases the applicability for endovascular repair of aortoiliac aneurysms. However, buttock claudication and erectile dysfunction are a drawback in a substantial number of patients.

Intraluminal 192Ir brachytherapy following transjugular intrahepatic portosystemic shunt revision: long-term results and radiotherapy parameters

PURPOSE

The stenosis or occlusion of transjugular intrahepatic portosystemic shunt (TIPS) occurs in up to 75% of patients within 12 months after treatment. The aim of our investigation was to evaluate the feasibility, safety and efficacy of intraluminal high-dose rate brachytherapy (HDRBT) with Iridium-192 following TIPS revision to prevent restenosis due to pseudointimal hyperplasia.

MATERIALS AND METHODS

Between September and November 1996, intraluminal BT was performed in five patients after TIPS revision. The indications for initial TIPS were a Budd-Chiari syndrome in two female patients and recurrent variceal bleeding by alcoholic liver cirrhosis in three male patients. TIPS was created with Wallstents (10 mm diameter in four patients) and Palmaz stent (10 mm diameter in one patient). The re-dilatation was done in all five patients 6 months after first stenting because of restenosis (>50% stent lumen reduction) or occlusion of the stent. A 5-French closed-tip, noncentered BT delivery catheter was used for subsequent radiotherapy. The whole length of the stent and performed dilatation (interventional length - IL) was taken as clinical target length (CTL). A 10-mm safety margin was added proximal and distal to the CTL due to uncertainties of BT source positioning, so forming the planning target length (PTL). To ensure that prescribed dose covers the whole PTL, the active source length (ASL) was 5 mm longer proximal and distal than PTL, so forming the reference isodose length (RIL). A dose of 12 Gy was prescribed in 3 mm distance from the source axis in the mid-plane of the applicator for three patients and in 5 mm distance for two patients.

RESULTS

A normal patency (<50% lumen reduction) of the stent was achieved at 44 months follow-up (duplex sonography+portography) in all three patients with liver cirrhosis, whereas further revisions were necessary in two patients with Budd-Chiari syndrome (after 5.5 and 18 months). No acute, subacute or late brachytherapy (BT)-related side effects were seen until now.

CONCLUSIONS

HDRBT following TIPS revision was safe and feasible in all patients. The exact impact of BT on the TIPS patency should be evaluated in larger clinical trials. Moderate dose escalation and use of today's commercially available centering radiation catheters seem to be necessary.

rt-PA thrombolysis in acute thromboembolic upper-extremity arterial occlusion

PURPOSE

Retrospective analysis of the results of rt-PA thrombolysis in the treatment of acute thromboembolic occlusion of the upper limb.

METHODS

Of 55 patients with demonstrated acute embolic arterial occlusion, rt-PA thrombolysis was performed on 40 occlusions in 38 patients (23 women with a mean age of 62 years, range 32-85 years; 15 men with a mean age of 65 years, range 32-92 years) according to the following design: 6 mg rt-PA/hr for 30 min, 3 mg rt-PA/hr for the next 30 min, 1 mg rt-PA/hr for 7 hr, and 0.4 mg rt-PA/hr until the end of lysis. Onset of symptoms varied from 1 to 14 days. Included were three isolated upper-arm occlusions, nine combined brachial and forearm occlusions, and 28 forearm and hand artery occlusions.

RESULTS

The overall success rate was 55%. The lysis results for isolated upper arm, combined brachial and forearm occlusions, and forearm and hand artery occlusions were 100%, 66%, and 46%, respectively. In eight patients surgical embolectomy had to be performed after failed thrombolysis. No amputation was required in the follow-up period. No lethal complications occurred.

CONCLUSIONS

Interventional rt-PA treatment of proximal upper-extremity arterial occlusions may be performed with comparable success rates to surgical embolectomy and without severe complications. For distal occlusions the results are inferior to the success rates obtained with surgery.

Biocompatibility and performance of the Wallstent and several covered stents in a sheep iliac artery model

PURPOSE

To compare the biocompatibility and performance of various stent-grafts to those of a bare stent in an ovine model with a subchronic (3 months) endpoint.

MATERIALS AND METHODS

Three different types of stent-grafts (ePTFE/nitinol, n = 8; polyester/nitinol, n = 8; and polycarbonate urethane/cobalt-alloy, n = 8) and a bare stent as a control (Ni-Co-Ti-steel-alloy, n = 8) were implanted in the iliac arteries in eight female sheep. One type of each stent-graft was implanted per animal, two implants at each side. The implantation sites for each type varied from animal to animal. Angiographic control and intravascular ultrasound (IVUS) imaging were performed before and after implantation, after 2 months, and before explantation at 3 months and were used to characterize patency and to assess intimal hyperplasia. After 3 months, the implants were retrieved and subjected to histologic evaluation (after methacrylate embedding, cutting, and histologic staining) to characterize the biologic response.

RESULTS

Implantation was technically successful in all procedures. At 2 and 3 months after implantation, all segments in which stents had been implanted were patent. Marked neointima formation was found in the polyester-covered stent-graft that showed significant luminal narrowing of 50%, compared to the ePTFE-covered (24%) and polycarbonate urethane-covered endoprostheses (22%), as well as the bare stent (Wallstent; 9%; P < .001). A minimal inflammatory vessel wall reaction was demonstrated for the polyester-covered and ePTFE-covered endoprostheses; the polycarbonate urethane-covered stent-graft's response was demonstrable but not significantly different from that of the Wallstent. At 3 months, the ePTFE-covered stent-graft showed incomplete (>90%) endothelial coverage; in the other endoprostheses, complete but partially immature endothelialization was found.

CONCLUSION

All stent-grafts induced an inflammatory vessel wall reaction with neointimal hyperplasia. The polyester-covered endoprosthesis caused a marked reaction with 50% luminal stenosis. Endothelialization was retarded with the ePTFE-covered stent-graft. The bare stent performed best in regard to neointimal formation and caused the least inflammatory response.

Glue embolization of a ruptured celiac trunk pseudoaneurysm via the gastroduodenal artery

Percutaneous transcatheter embolization of splanchnic artery aneurysms is a minimally invasive and alternative therapy to conventional surgical intervention. Due to a high-grade stenosis at the origin of the celiac trunk, a retrograde approach to the celiac trunk pseudoaneurysm via the gastroduodenal artery was necessary. To prevent undesirable embolization into the peripheral left gastric artery initial occlusion of the central portion of the left gastric artery was performed with microcoils using a Tracker catheter. Complete occlusion of the celiac trunk itself and the short adjacent segments of the celiac artery was achieved by using a mixture of N-butyl-2-cyanoacrylate and ethiodized oil as the embolizing agent.

PTA versus Palmaz stent placement in femoropopliteal artery obstructions: a multicenter prospective randomized study

PURPOSE

To evaluate if stent placement is superior to percutaneous transluminal angioplasty (PTA) in the treatment of chronic symptoms in short femoropopliteal arterial lesions.

MATERIALS AND METHODS

One hundred fifty-four limbs in 141 patients who ranged in age from 39 to 87 years (mean age, 67 years) were randomized to PTA (n = 77) versus PTA followed by implantation of Palmaz stents (n = 77). Inclusion criteria were patients with intermittent claudication (n = 108, Society of Vascular Surgery/International Society of Cardiovascular Surgery [SVS-ISCVS] categories 1-3) or chronic critical limb ischemia (n = 46 with either ischemic rest pain [category 4] or minor tissue loss [category 5]), short stenosis or occlusion (lesion length < or = 5 cm), and at least one patent run-off vessel at angiography. Follow-up included clinical assessment, measurement of ankle/ brachial index (ABI), color duplex ultrasound, and/or angiography at 6 or 12 months. Angiographic follow-up between 12 and 36 months was available in 46 limbs (29.9%).

RESULTS

In the PTA group, initial technical success was achieved in 65 of 77 limbs (84%) versus 76 of 77 (99%) limbs in the stent group (chi2 value = 0.009). Overall, major complications occurred in 3.9% (n = 6); n = 4 in the PTA group compared to n = 2 in the stent group. There was no difference between groups of treatment: hemodynamic/clinical success at 1 and 2 years in the PTA group was 72% and 65% versus 77% and 65% in the stent group (Gehan P value = .26). The cumulative 1- and 2-year angiographic primary patency rates were 63% and 53%, respectively, for both groups. The secondary 1- and 2-year angiographic patency rates were 86% and 74% in the PTA group versus 79% and 73% in the stent group (P = .5).

CONCLUSION

After stent placement, the primary success rate was significantly higher than after PTA. However, 1-year angiographic and clinical/hemodynamic success was not improved.

Simple and effective technique of guided biopsy in a closed MRI system

BACKGROUND

Magnetic resonance (MR)-guided biopsies are generally regarded as complex interventions. We implemented interventional MR (IMR) with the resources available in and for practical application in a large (1100 beds) central hospital.

METHODS

This simple and straightforward IMR technique uses a step-by-step approach for localization, access route planning, biopsy, verification in at least two planes, and postoperative control. The technique has been used and evaluated unchanged for more than 400 punctures and interventions.

RESULTS

Contrast, signal, matrix options, and visibility of needle track and tip permit uncomplicated orientation. The mean duration of a biopsy is 19 min. The technique can be applied to all radiologic puncture settings without any technical or medical complications.

CONCLUSION

The crucial step in implementing IMR is not to contemplate its application but to simply start applying the procedure.

Peripheral arterial obstruction: prospective study of treatment with a transluminally placed self-expanding stent-graft. International Trial Study Group

PURPOSE

To evaluate the safety and efficacy of an endoluminal prosthesis for treatment of peripheral arterial occlusive disease (PAOD).

MATERIALS AND METHODS

A self-expanding endoprosthesis with an expanded polytetrafluoroethylene tube inside a nitinol support structure was implanted in 127 patients with symptomatic PAOD in the iliac (61 limbs) and femoral arteries (80 limbs). Clinical category status, ankle-brachial index, and color duplex flow imaging results were recorded before treatment, at discharge, and at 1, 3, 6, and 12 months after treatment. Aspirin was administered throughout the study, and heparin was administered during and for 2 days after the procedure.

RESULTS

Endoprosthesis deployment was technically successful in all patients. Complications occurred in 24 of 141 procedures and included three major complications. Early thrombosis (within 30 days) occurred in one iliac and three femoral arteries. Late restenosis or reocclusion was observed in five iliac and 14 femoral arteries within the 1st year. Primary patency rates in iliac arteries were 98% +/- 3% (standard error) and 91% +/- 4%, respectively, at 6 and 12 months after treatment. Primary patency rates in femoral arteries were 90% +/- 3% and 79% +/- 5%, respectively, at 6 and 12 months. Secondary patency rates were 95% and 93% for iliac and femoral arteries, respectively, at 12 months after treatment.

CONCLUSION

The device used in this study can be implanted without additional risks to the patient and provided encouraging patency rates up to 1 year.

Contrast-enhanced magnetic resonance angiography in the evaluation of peripheral bypass grafts

The aim of this study was to determine the potential of contrast-enhanced magnetic resonance (MR) angiography in the evaluation of peripheral bypass grafts. Digital subtraction angiography (DSA) served as a standard of reference. Thirty-five patients with previous bypass graft surgery underwent DSA and contrast-enhanced MR angiography within 2 weeks. MR angiography was performed using a three-dimensional fast gradient-echo sequence after administration of gadopentetate dimeglumine. Every leg was divided into 11 segments and scored in five categories of stenosis. MR angiography findings were compared with those of DSA. A total of 38 bypass grafts and 454 segments in 27 patients were included in the evaluation. In 33 (87%) bypass grafts stenosis grading with both methods corresponded, and in 5 (13%) cases stenosis was overestimated on MR angiography. Agreement in detection of hemodynamically significant stenosis (stenosis =50%) was 94.7% with a sensitivity of 100% and a specificity of 91.3%. In 340 (83.0%) vascular segments there was conformity in graduation, in 69 (16.88%), there was a difference of one or more grades on MR angiograms. Forty-four segments (9.6%) were not assessable due to technical limitations. Contrast-enhanced MR angiography is an useful noninvasive tool in the detection of failing peripheral vascular bypass grafts.

Preoperative fast MRI of brain tumors using three-dimensional segmented echo planar imaging compared to three-dimensional gradient echo technique

The purpose of this study was to compare the diagnostic efficacy of a newly developed T(1)-weighted three-dimensional segmented echo planar imaging (3D EPI) sequence versus a conventional T(1)-weighted three dimensional spoiled gradient echo (3D GRE) sequence in the evaluation of brain tumors. Forty-four patients with cerebral tumors and infections were examined on a 1.0 T MR unit with 23 mT/m gradient strength. The total scan time for the T(1) 3D EPI sequence was 2 min 12 s, and for a conventional 3D GRE sequence it was 4 min 59 s. Both sequences were performed after administration of a contrast agent. The images were analyzed by three radiologists. Image assessment criteria included lesion conspicuity, contrast between different types of normal tissue, and image artifacts. In addition, signal-to-noise and contrast-to-noise-ratio (C/N) were calculated. The gray-white differentiation and C/N ratio of 3D EPI were found to be inferior to conventional 3D GRE images, but the difference was not statistically significant. In the qualitative comparison, lesion detection and conspicuity of 3D EPI images and conventional 3D GRE images were similar, but a tow-fold reduction of the scanning time was obtained. With the 3D EPI technique, a 50% scan time reduction could be achieved with acceptable image quality compared to conventional 3D GRE. Thus, the 3D EPI technique could replace conventional 3D GRE in the preoperative imaging of brain.

Primary implantation of polyester-covered stent-grafts for transjugular intrahepatic portosystemic stent shunts (TIPSS): A pilot study

PURPOSE

To investigate whether placement of a polyester-covered stent-graft increases the primary patency of transjugular intrahepatic portosystemic stent shunts (TIPSS).

METHODS

Between 1995 and 1997 Cragg Endopro or Passager MIBS stent-grafts were used for the creation of TIPSS in eight male patients, 35-59 years of age (mean 48 years). All patients suffered from recurrent variceal bleeding and/or refractory ascites due to liver cirrhosis. Seven stent-grafts were dilated to a diameter of 10 mm, one to 12 mm. Follow-up was performed with duplex ultrasound, clinical assessment, and angiography.

RESULTS

The technical success rate for creation of a TIPSS was 100%. The mean portosystemic pressure gradient decreased from 25 mmHg to 12 mmHg. In seven of eight patients TIPSS dysfunction occurred between 2 days and 3 years after stent-graft placement. In one patient the TIPSS is still primarily patent (224 days after creation). The secondary patency rates are 31 days to 3 years.

CONCLUSION

The primary use of polyester-covered stent-grafts for TIPSS did not increase primary patency rates in our small series.

[PTA vs. stent in femoro-popliteal obstruction]

PURPOSE

To evaluate whether primary stenting is superior to balloon angioplasty (PTA) alone in the treatment of femoropopliteal obstructive disease.

MATERIALS AND METHODS

Sixty-two patients, 24 female and 38 male, mean age 67 years (39-87) years, were randomized to PTA alone (n = 37) or balloon angioplasty followed by implantation of Palmaz stents (n = 33). Follow-up included clinical assessment, ankle-brachial index (ABI), color duplex ultrasound at 1, 3, 6 and 12 months after intervention and intravenous angiography at 6 or 12 months.

RESULTS

We had four cases of primary PTA failures (10.8%) and no early (< 30 days) thrombosis compared to one primary stent failure (3.0%) and three early thromboses (9.0%) in the stent group. Cumulative primary angiographic patency rates (life-table analysis) for PTA alone were 82% and 72% (6 and 12 months, respectively) compared to 81% and 60% for primary stent placement. The secondary angiographic patency were 97% and 88% for PTA and 88% and 72% for stent implantation, respectively. However, there was no significant difference in patency rates.

CONCLUSIONS

Despite fewer primary technical failures, mid-term angiographic and clinical patency were not improved by primary stent placement compared to PTA alone.

[Simple and effective rt-PA thrombolysis design]

PURPOSE

Assessment of a novel, simple and practical thrombolysis scheme for the purposes of a central hospital.

MATERIALS AND METHODS

314 thromboembolic lower extremity occlusions in 260 consecutive patients were treated by thrombolysis as follows: 6 ml rt-PA/h for 30 min; 3 ml rt-PA/h for another 30 min; 1 ml rt-PA/h for 7 hours, and 0.4 ml rt-PA until vessel patency. Antegrade introduction of a 5 F straight end-hole catheter through a 6 F, constantly heparin-flushed sheath, to the level of occlusion was followed by subsequent advancement of the catheter tip according to progress of lysis at time intervals of 2, 4, and 8 hours. The regimen was continued overnight.

RESULTS

82% of arterial occlusions were completely recanalized at the end of thrombolysis. Then, angioplasty was performed if appropriate. Best results (100% recanalization rate) were achieved by treating occlusions of the superficial femoral artery, even in cases of involvement of the entire length of the vessel, and isolated popliteal occlusions. A recanalization rate of 70% was achieved by treating distal crural vessel occlusion. Bypass grafts were recanalized in 50%.

COMPLICATIONS

3 x major hematoma, 2 x transluminal perforation; 16 x minor hematoma from the puncture site at the sheath, 4 x erythema, obviously reaction to rt-PA (together n = 25; 8%).

CONCLUSIONS

We empirically found and solidly evaluated an effective thrombolysis scheme. Our results demonstrate that major advances are possible even in this well-grounded field.

Kinetics of apoptosis and secondary necrosis in cultured rat thymocytes and S.49 mouse lymphoma and CEM human leukemia cells

Cell culture systems are widely used to study metabolic changes during apoptosis. In cell culture, unlike in vivo, apoptotic cells are not phagocytosed and eventually lyse (secondary necrosis). This is of practical importance because metabolic changes seen in cultures may be due to the transition from apoptosis to necrosis, rather than to the induction of apoptosis itself. In the present study, we followed the kinetics of the occurrence of several indicators of cell death in rat thymocytes and mouse lymphoma (S.49), and human leukemia (CEM) cell cultures after dexamethasone treatment (10(-6) M). The presence of apoptosis and secondary necrosis was demonstrated by electron microscopy. Nuclear condensation and fragmentation, which are considered to reflect early stages of apoptosis, were visualized with Hoechst fluorescent dye H 33258 for quantitative determination by light microscopy. In S.49 and CEM cultures their incidence increased after glucocorticoid treatment, but remained at relatively low levels not exceeding 6-9% until 36 h (S.49) or 3-4% until 92 h (CEM). The trypan blue positive cells, however, increased steadily to about 60%. Furthermore, flow cytometry (single parameter DNA analysis after propidium iodide staining) revealed the occurrence of cells with reduced DNA fluorescence. Morphological and biochemical (internucleosomal DNA cleavage) analysis of FACS-sorted cells showed that early after dexamethasone the majority of them were apoptotic. In S.49 and CEM cell cultures no clear-cut time lag between increase in cells with reduced DNA fluorescence, chromatin condensation/fragmentation, and the uptake of trypan blue could be detected.(ABSTRACT TRUNCATED AT 250 WORDS)