Balloon venoplasty of acute subclavian vein thrombosis.

Two patients with subclavian vein thrombosis are presented in which a balloon venoplasty led to recanalization of the subclavian vein and complete remission of clinical symptoms. In patients with extreme symptoms and unsuccessful initial catheter-directed local thrombolysis, this non-operative approach can be considered despite known favourable spontaneous outcome of subclavian vein thrombosis.

Optimisation strategies and justification: an example in uterine artery embolisation for fibroids.

Radiation risk has to be justified and optimised. This study discusses the radiation risk of uterine artery embolisation (UAE) for the treatment of fibroids. A total of 70 consecutive UAE dosimetry parameters were assessed. Using Monte Carlo simulation, organ and effective doses and dose conversion coefficients (DCCs) (mSv Gy cm(-2)) were calculated. During UAE optimisation, avoidance of oblique views and use of last-image-hold (LIH) documentation instead of digital subtraction angiography (DSA) were investigated. Mean dose-area product (DAP) was 37.1 Gy cm2 (median 23.7 Gy cm2) and mean fluoroscopy time was 18.4 min (median 16.6 min). Dose values decreased as the study progressed: mean DAP for patients 1-21, 68.5 Gy cm2; patients 22-43, 35.7 Gy cm2; and patients 44-69, 13.0 Gy cm2. Average DCC for DSA image procedures was 0.572, yielding a mean effective dose of 29.6 mSv (median 17.1 mSv). For LIH-only procedures, an average DCC of 0.813 was estimated [using mean effective dose: 10.6 mSv (median 8.1 mSv)].

Patient radiation exposure in uterine artery embolization of leiomyomata: calculation of organ doses and effective dose.

The goal of this study was estimation of patient effective dose from uterine artery embolization of leiomyomata. Parameters and data relevant to patient dose were recorded for 33 consecutive procedures. Using Monte Carlo simulation of radiation transport, organ and effective doses were calculated in detail for a subset of five procedures, to estimate the effective dose for all procedures. Mean dose area product was 59.9, median 23.4, and range 8.8-317.5 Gycm(2). Mean absorbed ovarian dose was calculated as 51 mGy in the five procedures. Using the dose conversion factor estimated from the Monte Carlo simulation for all procedures a mean estimated effective dose of 34 mSv (median 13 mSv, range 5-182 mSv) results, with a tendency to lower values regarding the succession of the procedures. Patients' radiation exposure level is up to twice of that of an abdominal CT examination. Angiographic equipment related dose-reducing features and radiographic technique essentially influence organ doses and effective dose. Consistent application of dose-reducing techniques and awareness of radiation exposure justifies uterine artery embolization as a therapeutic option for the treatment of uterine fibroids.

Clinical aspects of quality criteria in digital radiography.

In clinical radiological practice two main questions regarding image quality have to be looked at: Which degree of image quality is needed? and: How can this image quality be objective? Image quality requirements depend on size, density and contrast of the objects of interest and on the clinical question which has to be answered. In comparison to conventional radiography, the digital radiographic techniques offer additional features concerning optimisation of image quality and dose, like a wider dynamic range, digital fluoroscopic techniques and post-processing. Therefore it is necessary to define new quality criteria for these techniques. In the following, typical examples demonstrate the development of the 'Diagnostic Requirements for Digital Radiographic Procedures'. These examinations include projection radiographs with digital luminiscent radiography, fluoroscopic procedures with digital image intensifier radiography and angiographic procedures with digital subtraction angiography. The clinical question of a radiological examination also forms the background to optimisation strategies considering image quality and radiation dose.

Popliteal artery stenting using flexible tantalum stents.

PURPOSE: To evaluate the safety and efficacy of stent therapy for the treatment of residual stenoses after percutaneous transluminal angioplasty (PTA) of popliteal stenoses and occlusions. METHODS: In a prospective single-center study, flexible tantalum stents were implanted in 32 popliteal arteries for the treatment of residual stenosis greater than 50% after PTA of stenoses (n = 17) or occlusions (n = 15) in the P1 (n = 16), the P2 (n = 13), or both P1 and P2 segment (n = 3). Follow-up patency was assessed by clinical examination, ankle-brachial index, and color Doppler sonography or angiography. RESULTS: Early stent thrombosis (10 days): 1 of 32 arteries (3%). 1-year and 2-year primary patency rate (PPR): 81% +/- 7.1% and 74% +/- 9.1%, respectively. 1-year PPRs for subgroups: stented stenoses versus stented occlusions: 88% +/- 7.8% vs 73% +/- 12.0%, p = 0.12; good lower limb runoff versus poor: 84.0% +/- 8.7% vs 76.0% +/- 12.4; p = 0.09; P1 versus P2: 77.3% +/- 9.8% vs 85.7% +/- 9.4%, p = 0.38. Recurrent PTA lesions treated with stents showed higher restenosis rate than de novo lesions. CONCLUSION: The results of stent therapy of residual popliteal stenosis after PTA are encouraging and warrant further investigation.

Flexible tantalum stents for the treatment of renovascular hypertension: a 10-year experience.

The aim of this study was to determine long-term success of flexible tantalum stents for the treatment of ostial and truncal renal artery stenosis. Since 1989, flexible tantalum stents (type Strecker) were implanted in 34 patients (36 arteries, 25 ostial lesions, 11 truncal lesions) with uncontrollable renovascular hypertension, 9 of them in association with renal insufficiency. Stents were placed unilaterally in 32 patients, and bilaterally in 2 patients for the treatment of renal artery stenosis. Thirty-five of 36 lesions were atherosclerotic, including 5 recurrencies after previous percutaneous transluminal renal angioplasty (PTRA). One patient had Takayasu arteritis. Stents were implanted after unsuccessful PTRA of 11 truncal and 23 ostial lesions, and as a primary procedure in 2 ostial lesions. Follow-up examinations included blood pressure measurement, determination of serum creatinine level, color duplex sonography, or angiography. The technical success rate was 92%. Technical failure included incorrect stent placement (1 of 36 lesions, 2.8 % ), and stent dislocation (2 of 36 lesions, 5.6 %), and two stents were retrieved percutaneously. In one case of Takayasu arteritis, residual stenosis of 40% was observed. After technically successful stent placement, 77% of patients became normotensive with or without medication. In the remaining patients there was partial improvement with blood pressure between 140 and 180 mmHg. Renal function improved in 76% of patients (completely in 3 of 8, 38%; and partially in 3 of 8, 38%). Primary patency rate including all stented lesions and initial technical failures was 82.4% +/- 6.8 (1 year) and 82.4% +/- 9.2 (3 years). After technically successful stent placement, patency rates were 89.9 +/- 5.6% (1 year), and 89.9 +/- 7.6% (3 years). For ostial lesions, primary patency rate was 87.9 +/- 6.7% (1 year) and 87.9 +/- 9.2% (3 years). Placement of flexible tantalum stents in renal arteries is technically demanding, especially in ostial lesions. Once placed successfully stent patency rate is excellent.

Current practice of temporary vena cava filter insertion: a multicenter registry.

PURPOSE: To evaluate the current practice of temporary vena cava filter placement and its complications. MATERIALS AND METHODS: A multicenter registry was conducted from May 1995 until May 1997 using a standardized questionnaire. One hundred eighty-eight patients were evaluated. Patient characteristics, filter indications, filter characteristics, and complications were registered. RESULTS: Deep vein thrombosis was proven in 95.2% of the patients. Main filter indication was thrombolysis therapy (53.1%). Average filter time was 5.4 days. An Antheor filter was inserted in 56.4%, a Guenther filter in 26.6%, and a Prolyser filter in 17.%. Transfemoral filter implantation was slightly preferred (54.8%). Four patients died of pulmonary embolism (PE) during filter protection. Major filter problems were filter thrombosis (16%) and filter dislocation (4.8%). When thrombus was found in or at the filter before explantation, additional thrombolysis was performed in 16.7%, additional filter implantation in 10%, and thrombus aspiration in 6.7%; 4.8% of filters were replaced with permanent filters. DISCUSSION: Temporary vena cava filters are placed to prevent PE in a defined patient population. Despite their presence, PEs still occur in a small percentage. Problems of filter thrombosis and dislocation have to be solved. CONCLUSION: The results of this multicenter registry support the need for innovative filter design, as well as a randomized, prospective study.

Improvement in claudication after angioplasty of distal ostial collateral stenosis in patients with long-segment occlusion of the femoral artery.

PURPOSE: To evaluate the angiographic and clinical effects of percutaneous transluminal angioplasty (PTA) of distal ostial collateral stenoses in patients with claudication and long-segment occlusion of the superficial femoral artery (SFA). METHODS: In ten patients (9 men, 1 woman) with stable intermittent claudication due to chronic long-segment occlusion of the SFA a high-grade stenosis of the distal collateral ostium of the deep femoral artery to the popliteal artery were dilated. PTA was performed using popliteal artery access. Claudication distances on the treadmill and ankle-brachial pressure indices (ABI) at rest were analyzed before, 1 week, and 14 weeks after PTA. RESULTS: Initial technical success was obtained in all patients. There were no significant periprocedural local complications. The initial mean claudication distance on the treadmill increased significantly from 107 +/- 65 m to 306 +/- 209 m (p < 0.01), the maximal claudication distance from 203 +/- 128 m to 392 +/- 167 m (p < 0.01). The mean ABI changed slightly but significantly (0.61 +/- 0.08 vs. 0.64 +/- 0.07; p < 0.05). Early follow-up after 14 weeks revealed no clinical deterioration. CONCLUSION: This new technique is considered helpful in patients with well-defined claudication and long-segment occlusion of the SFA.

Treatment of a recurrent choanal atresia by balloon dilatation.

A 16-year-old female patient with recurrent stenosis after unilateral choanal atresia that had been treated by surgery and laser therapy presented with restenosis 3 weeks after laser resection. As an alternative to repeat surgery, she was treated by balloon dilatation. Four balloon dilatations were performed (three at 4-week intervals and the last after an 8-week interval) over a 4-month period on an outpatient basis. She tolerated the treatment well without any complications. Over a follow-up period of 2 years the choana has remained completely open. The balloon dilatation described in this context here for the first time may be a good alternative to repeated operations in the treatment of recurrent choanal atresia, with minimal stress to the patient.

Correlation of hemodynamic and functional variables with the angiographic extent of peripheral arterial occlusive disease.

The aim of the study was to determine whether hemodynamic and functional variables are related to the angiographic extent of lower limb atherosclerosis. In 150 patients with stable intermittent claudication, the Bollinger angiogram score was compared with the resting Doppler pressure values, and the initial claudication distance (ICD) and absolute claudication distance (ACD) with treadmill exercise. The extent of lower limb atherosclerosis correlated significantly with the age of the patients and the duration of the claudication. The angiogram scores of the patients were negatively correlated with the ankle systolic blood pressure (SBP) and the ankle/brachial index (ABI). In a multiple regression analysis, ABI was the most predictive variable for the angiographic severity of disease. ICD, ACD and work on the treadmill failed to correlate with the angiogram summation score. If patients were classified into groups for those with iliac or femoropopliteal disease, a weak correlation between ACD and femoropopliteal angiogram score was found. The comparison between Doppler measurements and treadmill exercise testing showed no significant correlation between SBP/ABI of the more diseased limb and ICD. However, both SBP and ABI did correlate significantly with ACD (r = 0.16, p < 0.05 and r = 0.20, p < 0.01, respectively). In conclusion, SBP and ABI are reliable parameters for indirect assessment of the angiographic extent of lower limb atherosclerosis. In contrast, the walking capacity of claudicant patients is independent of the angiographic severity of the disease.

CT-guided epidural/perineural injections in painful disorders of the lumbar spine: short- and extended-term results.

PURPOSE: Evaluation of short- and extended-term results of repeated epidural/perineural injections (EDT/PRT) of corticoids in painful afflictions of the lumbar spine. METHODS: Thirty-two patients who had persistent radicular or low back pain for more than 6 weeks were treated with CT-guided injection therapy. By EDT/PRT, 40 mg of triamcinolonacetonid was injected either periradicularly or by a direct intraspinal epidural method at intervals of 3 weeks. Altogether, 140 EDT/PRT were performed in 32 patients (mean 4.4, range 2-8). In nine patients partial facet joint denervation with 1-2 ml of 50% alcohol solution was combined with EDT/PRT to reduce low back pain. Before and after treatment and at follow-up (mean 9.6 months), treatment success was evaluated on a visual analog scale and by physical examination (good = >50% improvement, moderate = 20%-50%, no improvement = <20%). RESULTS: Short-term (end of therapy) good or moderate improvement was achieved in 91% of patients, extended-term (mean 9.6 months) in 56%. Regarding certain subgroups, those with disc herniations of the lumbar spine showed a better outcome with good or moderate improvement in 95% short-term and 69% extended-term than those with spinal stenosis who had 72% short-term and 28% long-term. CONCLUSION: Results indicate that CT-guided EDT/PRT in combination with partial facet joint denervation is a safe and effective outpatient treatment.

[Dose-dependent decrease of the rate of restenosis of stents in peripheral vessels with reviparin]. / Dosisabhängige Senkung der Restenoserate von Stents in peripheren Gefässen mit Reviparin.

PURPOSE: In clinical prospective trials, we examined the effect of the low molecular weight heparin (lmwh) reviparin on restenosis rate after Strecker stent implantation in femoral popliteal arteries. MATERIALS AND METHODS: 62 patients were treated between 1992 and 1998. Patients received reviparin, 3500 IU, prior to stent implantation followed by 7500 IU for 24 h (i.v.) and 2 x 1750 IU/day s.c. over three weeks (n = 12) or 10,500 IU for 24 h (i.v.) and 2 x 3500 IU/day s.c. over 3 1/2 weeks (n = 50). Follow-up parameters were clinical symptoms, ankle-brachial index, color Doppler flow duplex sonography, and DSA. RESULTS: Three thrombotic occlusions and three stenoses were observed in the low-dose group. Raising the dose resulted in neither thrombotic nor other events within the first three months. Seven stenoses occurred afterwards up to the 7th month. The complication rate was low: one moderate hematoma and one puncture aneurysm. Primary patency rate was 88% and 80% for one and two years, respectively. This is significantly better than the primary patency rates for patients receiving low-dose lmwh (p < 0.005) or unfractionated heparin (p < 0.05). CONCLUSIONS: Hence, high-dose administration of the lmwh reviparin lowers the restenosis rate after stent implantation in femoropopliteal arteries.

Low-molecular-weight heparin (reviparin) reduces the incidence of femoropopliteal in-stent stenosis: preliminary results of an ongoing study.

PURPOSE: To examine the efficacy of the low-molecular-weight heparin, reviparin, for prevention of femoropopliteal stent restenosis. METHODS: Forty-two patients who had implantation of flexible tantalum stents for the treatment of stenosis (n = 24) or occlusion (n = 18) of the femoral (n = 27) or popliteal (n = 15) arteries were included in this study protocol. An intraarterial bolus of 5000 IU heparin was given before percutaneous transluminal angioplasty (PTA), and in the case of stent implantation due to unsuccessful PTA, an additional dose of reviparin (3500 anti-factor Xa IU) was given. Postprocedurally, 10,500 anti-factor Xa IU of reviparin were administered intravenously over 24 hr, followed by 3500 anti-factor Xa IU subcutaneously twice a day for 23 days. Oral aspirin (100 mg/day) was prescribed for the long term. Follow-up criteria (maximum follow-up 37 months) were clinical symptoms, Doppler ankle arm indices, color and duplex sonography, and angiography for suspicion of restenosis. RESULTS: Early stent thromboses were not observed. Overall primary patency rate (PPR) was 88% +/- 6.0% (1 year) and 74% +/- 10.1% (2 years). Major hemorrhagic complications have not occurred. CONCLUSION: Reviparin administered in a high dose over a period of 24 days is a safe medication regimen and provides excellent patency rates after stent implantation.

Effect on intimal hyperplasia of dexamethasone released from coated metal stents compared with non-coated stents in canine femoral arteries.

PURPOSE: Polymer-coated, dexamethasone (DXM)-releasing stents were tested in order to assess the efficacy of DXM released locally for the prevention of stent restenosis due to intimal hyperplasia. METHODS: Strecker stents coated with a biodegradable membrane containing DXM were implanted percutaneously into the femoral artery in 14 dogs. The contralateral artery received a conventional non-coated stent serving as control. The drugs are eluted by degradation of the carrier membrane. Follow-up intraarterial digital subtraction angiography (DSA) was obtained at 3, 6, 9, 12, and 24 weeks with subsequent autopsy. Specimens for gross and microscopic pathology were obtained and histomorphometry was performed. RESULTS: Four of 14 DXM-coated stents showed thrombotic occlusion within the first 3 weeks; ten DXM-coated stents remained patent. At follow-up DSA, DXM-coated stents showed a significantly wider lumen than the non-coated stents. At morphometry there was less intimal hyperplasia over DXM-coated stents than over non-coated stents (p < 0.05). CONCLUSION: DXM-coated stents reduce neointimal hyperplasia in dogs when compared with non-coated stents.

[Clinical aspects of image quality and doses in gated pulsed imaging]. / Klinische Aspekte zu Bildqualität und Dosis bei gittergesteuerter gepulster Durchleuchtung.

PURPOSE: The relations between image quality in last image hold images and dose in grid controlled fluoroscopy in comparison to the continuous mode need to be characterised and recommendations for the clinical application of this technique should be given. MATERIAL AND METHODS: Spatial resolution, signal-noise ratio and, contrast-detail visibility were evaluated by phantom measurements in grid controlled pulsed and continuous fluoroscopy. Dose was measured at the image intensifier entrance. Image quality of last image hold (LIH) images of clinical examinations was graded in relation to single shot exposures. RESULTS: Signal-noise ratio and contrast-detail visibility depend on the dose per puls. Spatial resolution and contrast-detail visibility in grid controlled fluoroscopy are superior than to in the continuous mode. Image quality of the LIH images from the grid controlled fluoroscopy was improved. Radiation exposure could be reduced to 10-46%. CONCLUSIONS: Combinations of puls-dose and -frequency are recommended for achieving extensive dose reduction and improved image quality of LIH images.

Intraarterial infusion therapy via a subcutaneous port for limb-threatening ischemia: a pilot study.

PURPOSE: To present the initial results of a new percutaneously implantable catheter port system (PIPS) used for long-term intraarterial infusion therapy in patients with severe ischemic limb disease. METHODS: Ten patients with deep, extended ischemic ulcerations (all 10) and osteomyelitis (6/10) of the foot received intraarterial infusions of prostaglandine E1 and antibiotics, if indicated, via a new port catheter system with the port placed subcutaneously above the groin after percutaneous introduction and the catheter tip placed into the superficial or deep femoral artery. RESULTS: Port implantation and repeated port access were uncomplicated. During the follow-up period (mean 11 months, range 1 week-50 months), port migration, leakage, or infection was not observed. Three catheters thrombosed and were opened by fibrinolysis with recombinant tissue plasminogen activator instilled via the port. Treatment success was achieved in 8 patients: relief from rest pain (8 patients), reduction of ulcer size (4/8), and complete healing (4/8). Limb savage rate was 80%. In 2 patients amputation could not be avoided. CONCLUSION: Selective long-term arterial infusion therapy presents a valuable therapeutic regimen for limb salvage. With the new catheter port system, repeated local intraarterial infusion is safe and simple.

Femoropopliteal artery stent placement: evaluation of long-term success.

PURPOSE: To evaluate the long-term success of femoropopliteal artery stent placement after technical failure of balloon angioplasty and to determine potential factors predictive of stent failure. MATERIALS AND METHODS: In 80 patients, flexible tantalum stents were implanted for treatment of residual stenosis greater than 30% after balloon angioplasty of femoropopliteal artery stenoses (n = 33) or occlusions (n = 47). Follow-up examinations were performed at 1-72 months to evaluate early and late stent failure according to risk factors such as lesion type, anatomic location, stent length, runoff quality, and restenosis after balloon angioplasty. RESULTS: Early stent thrombosis occurred within 10 days after stent placement in four (5%) patients; the frequency was higher (P < .01) in stents longer than 4 cm (14%) versus that in stents 4 cm or shorter (2%). For all stents, the 2-year primary patency rate was 51% and the 3-year rate was 48%. The 2-year primary patency rate was significantly better (P < .05) for shorter stents (59%) versus that for longer stents (30%) and for treated stenoses (73%) versus treated occlusions (33%). Multivariate analysis revealed that lesion type and lesion length were the most reliable factors predictive of stent failure. CONCLUSION: Successful stent therapy does not seem to depend on the type of stent used but rather on lesion type, lesion length, and other predisposing factors.

Preoperative embolization of cervical spine tumors.

PURPOSE: To assess the technical success rate, complications, and effect on intraoperative blood loss of preoperative transarterial embolization of cervical spine tumors. METHODS: A retrospective analysis was performed on 38 patients with tumors of the cervical spine; 69 vertebrae were affected. Polyvinyl alcohol particles, coils, gelfoam particles, either alone or in combination, were used for preoperative tumor embolization. After embolization a total of 57 corporectomies with titanium basket implantation were performed. RESULTS: In 36 of 38 patients, complete (n = 27) or partial (n = 9) embolization was achieved. In 23 patients one vertebral artery was completely occluded by coil placement, and in one patient the ipsilateral internal and external carotid arteries were occluded in addition. No neurological complications could be directly related to the embolization, but two postoperative brain stem infarctions occurred. The mean intraoperative blood loss was 2.4 L. CONCLUSION: Transarterial embolization of cervical spine tumors is a safe and effective procedure to facilitate extensive surgery.

[Studies of image quality and dose in digital subtraction angiography]. / Untersuchungen zu Bildqualität und Dosis bei der DSA.

METHODS: The dose needed for high image quality in l.a. DSA, was determined by investigation of the necessary relationship between dose and image quality. This method is based on measurements of the signal-to-noise ratio and of the contrast-detail detectability. It has been tested on two different systems (Philips integris V3000, Philips Diagnost 97). RESULTS: Our measurements prove that an image intensifier entrance dose of 1.1 microGy (image intensifier diameter 38 cm) is sufficient for high image quality in DSA. An increased dose value does not lead to an improvement in image information. For details larger than the pixel size the 512 matrix produces a higher signal-to-noise ratio with a higher contrast-detail detectability, whereas higher spatial resolution results by the use of a 1024 matrix. In rotational angiography, high image quality can be achieved at an image intensifier entrance dose of 1.1 microGy. In contrast to sequences without rotation, image quality is decreased through movement unsharpness. As the maximum exposure time 25 ms should be selected. The use of a 1024 matrix does not lead to a better spatial resolution in rotational angiography.

Percutaneously implantable catheter-port system: preliminary technical results.

The function and safety of a percutaneously implantable catheter-port system were studied in 44 patients with different diseases (32 patients with malignant disease, 11 with peripheral arterial disease, and one with recurrent asthmatic attacks). Most patients required repeated local-regional arterial infusion. Infection (two patients) and catheter-related complications (10 patients) were observed during the follow-up period (maximum length of follow-up, 542 days; mean, 177 days). Port migration or leakage did not occur. The data suggest that this new catheter-port system is safe and easy to handle.