[Certification of vascular centers. Influence on quality and healthcare structures]. / Zertifizierung von Gefäßzentren. Auswirkungen auf Qualität und medizinische Versorgungsstrukturen.

Diagnosis and therapy of vascular diseases are increasingly being performed following a multimodal, interdisciplinary and less invasive approach. The introduction of specialized, organ-related centers is a logical consequence in view of a better treatment quality and a more effective use of resources. The German societies of radiology, vascular surgery and angiology jointly developed a process of certification, which has been successfully applied to more than 100 units in Germany. In this article the terms and results of the process are described and possible effects on the quality and structures of the healthcare system are discussed.

[Chitosan pads vs. manual compression to control bleeding sites after transbrachial arterial catheterization in a randomized trial]. / Randomisierte Untersuchung zur Anwendung eines Chitosan-Gerinnungspads zur Blutstillung bei transbrachialen Angiographien.

PURPOSE: Until now, no mechanical closure devices were available to achieve fast and secure hemostasis for vessel closure after catheterization of small arterial vessels. MATERIAL AND METHODS: Eighty patients were randomized to evaluate the effect on hemostasis by use of a chitosan pad (Chito-Seal, Abbott Vascular Devices, Galway/Ireland) in comparison to manual compression after diagnostic transbrachial arterial catheterization. Hemostasis after three minutes and one hour as well as local development of a hematoma after one and twenty-four hours were assessed. RESULTS: The use of chitosan pads significantly decreased the bleeding time in the first three minutes after manual compression time (p < 0.01). Significant decrease in bleeding risk at three minutes by use of the chitosan closure pads was also found in subgroups of patients with hypertension (p < 0.001) or diabetes (p < 0.01) and also in patients under anticoagulation therapy (p < 0.01). In addition, long-term protection from bleeding complications such as the risk of hematoma was decreased by the use of chitosan closure pads one hour (p < 0.01) or twenty-four hours (p < 0.001) after catheter removal. CONCLUSION: The use of an intravascular anchor or suture system is not safely applicable in these vessels due to the small diameter of the brachial artery. Our results document a significant improvement in hemostasis by using chitosan pads in these cases.

Tissue response of the biliary and digestive system of rabbits after MTBE infusion into the gallbladder.

We evaluated the tissue response of the biliary and digestive system after Methyl-tert-Butyl-Ether (MTBE) gallbladder infusion in 32 rabbits. After laparotomy, MTBE (5-11 ml) was infused into the gallbladder for eight hours. Animals were sacrificed after eight hours or after two months. Control animals received saline solution infusion into the gallbladder. Afterwards the gallbladder, the common bile duct, the liver, the pancreas and the duodenum were examined histologically. All animals receiving MTBE had different degrees of gallbladder necrosis, common bile duct necrosis and necrosis of intrahepatic bile ducts. After two months, scar formation and a hyperplastic cholecystitis were observed. Control animals did not have comparable tissue reactions; only small areas of necrosis in the gallbladder and the common bile duct occurred after eight hours. The gallbladder, common bile duct and liver remained unchanged in those animals which survived two months. Although the results of this animal study cannot be directly transferred to humans, the data suggest that MTBE should be used in gallstone therapy with caution, and that if it is used, a well-controlled follow-up of these patients is necessary.

Vascular tissue ablation by an erbium-YAG laser: a fiber-transmittable pulsed laser in the infrared range.

Vascular tissue ablation by an erbium:YAG laser of 2,940 nm was tested in-vitro with the application of increasing energies from 20 to 80 mJ per pulse. Effective ablation of normal vascular tissue, lipomatous atheromas and calcified plaques was achieved. Penetration depth was considerably diminished in the presence of calcifications. The lasered craters showed smooth surfaces and were regularly shaped. The solid state erbium:YAG, which is transmittable by fluoride fibers, offers theoretical advantages for laser angioplasty.

Thermal laser-induced stenosis of the common bile duct. An alternative model for experimental research.

An experimental model of bile duct stenosis and occlusion in dogs is presented. After percutaneous cholecystostomy of the gallbladder, which had been affixed to the abdominal wall during laparotomy four weeks earlier, a standard 2 mm laser heat probe adapted to an Nd:YAG laser (1,064 nm) was advanced inside the proximal common bile duct in 12 animals, using 6 or 7 F sheaths. The proximal part of the common bile duct was exposed to laser pulses of 6 to 10 Watts for one second. Within 3 to 15 days, total occlusion or severe stenosis of the common bile duct consistently occurred and was verified by follow-up percutaneous cholecystocholangiography. No perforations occurred. Compared with other models, laser thermal damage is an easy and reliable method of producing bile duct stenoses for experimental purposes.

Color-coded duplex sonography of experimentally induced multilevel stenosis. Evaluation of poststenotic Doppler spectrum.

RATIONALE AND OBJECTIVES: The authors evaluated the influence of a proximal arterial stenosis on the poststenotic doppler spectrum of a second, distal stenosis and determined duplex parameters, which permitted description of the severity of the distal stenosis. METHODS: Moderate (ie, 50%) and severe (ie, 90%) stenoses of the distal aorta and the distal iliac arteries of 10 pigs were created surgically and characterized by angiography. All possible combinations of moderate and severe stenoses were examined. The Doppler spectrum was depicted in the distal iliac and distal femoral arteries of both limbs and analyzed by use of maximum and minimum flow velocity (Vmax, Vmin), acceleration index (modified Handa index), acceleration time, and pulsatility index. RESULTS: In cases of moderate as well as severe proximal stenosis, acceleration index, acceleration time, and pulsatility index of the poststenotic curve of the distal stenosis were significantly reduced (P < 0.05). Independent of the severity of the proximal stenosis, differentiation of moderate as well as severe distal stenosis was possible (P < 0.05) with these parameters. CONCLUSIONS: Despite interference of spectral curves in proximal and distal stenosis, duplex sonography enabled the differentiation of experimental aortic iliac multilevel stenosis.

In vitro ablation of normal and diseased vascular tissue by a fiber-transmitted holmium laser.

An in vitro study was performed to test the ablative potential of a fiber-transmitted pulsed holmium laser (2.1 microns) applied to normal vascular wall, lipomatous plaques, and calcified plaques. Different fluences per pulse of 42, 80, 205, and 315 J/cm2 were used. Ablation of normal tissue and lipomatous plaques was achieved with all power settings. Effective ablation of calcified plaques, however, occurred only after a minimum fluence of 205 J/cm2, and the effect was significantly less pronounced compared to ablation of soft lesions.

Experimental arterial stent placement. Comparison of a new Nitinol stent and Wallstent.

RATIONALE AND OBJECTIVES: To compare technical aspects and neointima formation of a new Nitinol stent and a Wallstent. METHODS: A Nitinol sten and a Wallstent were placed into the iliac arteries of 14 sheep (total of 28 stents) and followed angiographically. Seven sheep were killed after 1 month and 7 after 4.5 months. Examination of histologic specimen by light microscopy was performed to determine neointimal and medial thickness inside the stents. Measurements were analyzed statistically. RESULTS: Neointima was thicker in Nitinol stents (N) than in Wallstents (W) (P < 0.004), both adjacent to (W = 0.265 mm, N = 0.596 mm) and between the stent wires (W = 0.177 mm, N = 0.361 mm). Because of poor radiopacity and the Crochê releasing technique, delivery was more difficult with Nitinol stents. High-grade stenosis was found in two Nitinol stents at 1 and 4.5 months of follow-up, respectively. One Wallstent was insufficiently incorporated into the vessel wall. CONCLUSIONS: The observed difference in neointima formation that may be caused by differences in design, mechanical properties or the metal alloy of the stents probably is too insignificant to be relevant to patency of large arteries. However, it may be relevant in small vessels such as coronary arteries.

Interventional magnetic resonance. Initial clinical experience with a 1.5-tesla magnetic resonance system combined with c-arm fluoroscopy.

RATIONALE AND OBJECTIVES: The authors evaluate the feasibility of performing magnetic resonance (MR) procedures on a 1.5-tesla (T) system combined with conventional c-arm fluoroscopy. METHODS: A 1.5-T MR imaging system was combined with a conventional c-arm fluoroscopy unit in one room. The two systems were connected via a floating table top. Twenty-six interventional procedures (biopsies, MR-portography, percutaneous alcohol injection, laser ablation, fluid aspiration, and breast marking) were performed in 22 patients under MR, fluoroscopic control, or both. For MR guidance, fast gradient echo sequences were used, initiated from a panel at the front of the magnet. Images were displayed on an liquid crystal display screen positioned on the magnet. RESULTS: All MR-guided procedures were performed successfully without complications. The addition of c-arm fluoroscopy was useful for bone interventions and MR-portography. All diagnostic biopsies yielded sufficient amounts of tissue for histologic diagnosis. In breast lesions, the target identified on dynamic MR imaging was marked correctly in each case. In interstitial laser thermotherapy the laser effect could be visualized, and in percutaneous ethanol injection the distribution of the alcohol could be seen. Both imaging systems worked without image distortions and high-quality MR images were obtained. CONCLUSIONS: The combination of a 1.5-T MR imager with a c-arm fluoroscopy system seems to be a promising technical solution for performing interventional MR procedures.

Bedside testing (SimpliRED) in the diagnosis of deep vein thrombosis. Evaluation of 250 patients.

RATIONALE AND OBJECTIVES: The authors evaluate the sensitivity and specificity of a bedside test (SimpliRED) in the diagnosis of deep vein thrombosis compared with contrast phlebography. METHODS: Two hundred fifty patients, referred for phlebography, underwent bedside testing for detection of deep vein thrombosis. Contrast phlebography was performed immediately afterward. SimpliRED provides a clearly visible agglutination of the patient's red blood cells in the presence of elevated levels of cross-linked fibrin derivative (D-dimer), which is specific for fibrin breakdown. RESULTS: In 82 (32.8%) patients, deep vein thrombosis was confirmed venographically. An abnormal D-Dimer test was found in 79 of the 82 patients with thrombosis (sensitivity: 96.3%). The three patients who were diagnosed falsely as normal on agglutinin testing, had venograms which showed only an isolated calf thrombosis in small muscle veins (< 2 cm in diameter) not requiring treatment. One hundred of 168 patients without venographic thrombosis were diagnosed correctly by SimpliRED (specificity: 59.5%). The positive predictive value was 53.7%; the negative predictive value was 96.8%. CONCLUSIONS: All thrombotic disorders in the leg that required further treatment were identified correctly. SimpliRED is a very sensitive test with moderate specificity in the diagnosis of deep vein thrombosis. Therefore, further invasive testing is needed only in those patients in whom the D-dimer test is abnormal. A false-positive result of the bedside test may be nonspecific or due to elevated levels of fibrin split products, which can occur whenever the coagulation system has been activated by any of several conditions.

S-1 radiculopathy as a possible predisposing factor in focal myositis with unilateral hypertrophy of the calf muscles.

Associated with chronic S-1 radiculopathy, a 44-year-old man developed unilateral hypertrophy of the calf muscles. Electromyography revealed neurogenic alterations in the corresponding limb compatible with S-1 radiculopathy. In addition, MR-tomographic and bioptic findings were consistent with a focal inflammatory myopathy of the enlarged right gastrocnemius muscle. Predisposing factors for the localisation of a focal myositis are unknown. This case report highlights the diagnostic difficulties in distinguishing focal myositis and denervation hypertrophy following S-1 radiculopathy or secondary inflammation related to denervation. We consider the possibility that in our case the inflammatory process might have been triggered by electromyographically proven chronic denervation related to radiculopathy.

Fine caliber cholangioscopy.

The miniaturized diameters of endoscopes (miniendoscopes) allow percutaneous access for endoscopic visualization of the extrahepatic and intrahepatic biliary system. Practical aspects of different miniendoscopes in an experimental model are described. Clinically, fine caliber cholangioscopy is helpful in detection of retained biliary stones. Nevertheless, discrimination of benign and malignant stenosis remains difficult, and simultaneous intervention under endoscopic guidance is compromised by the low steerability of the instruments.

[Endoluminal vascular prostheses]. / Endoluminale Gefässprothesen.

Endoluminal vascular prostheses that can be implanted by percutaneous routes represent the most recent development in vascular interventional radiology. Various commercially available types of prosthesis are presented and the construction principles and applications are described. At present secure indications for the implantation of endoluminal prostheses are limited to the elimination of aneurysms and arteriovenous fistulae of the large vessels near the trunk in sections that do not cross a joint. The wide use in peripheral occlusive diseases cannot yet be recommended because confirmed data are not available.

[Use of a new tiltable angiography table for diagnostic and interventional CO2 angiography]. / Nutzen eines neuartigen kippbaren OP-Angiographietisches bei diagnostischen und interventionellen CO2-Angiographien.

A new tiltable angiographic table was tested for its applicability during carbon dioxide angiography in 11 patients. A change of position could be performed easily without delaying the procedure time and improved image quality in 8 patients while carbon dioxide was applied as contrast agent. The new tiltable angio table--originally designed for surgical procedures performed within the angiosuite--proved to be of use also during percutaneous diagnostic procedures, particularly with carbon dioxide as a contrast agent.

[Long-term follow-up of vena cava filters: real-time sonography and the native x-ray image]. / Langzeitkontrollen bei Kavafiltern: Real-time-Sonographie und Nativröntgenbild.

In 16 patients with vena cava filters (12 Günther filters, 4 Kimray-Greenfield filters) a follow-up study was performed by ultrasound and abdominal plain film. Ultrasound allows to identify type and location of the filter as well as the entrapment of emboli. Abdominal radiography is useful for exact evaluation of changes in filter position. Combination of sonography and plain films is considered to be most suitable for follow-up studies of caval filters.

[Diagnosis of obstruction and stone passage following ESWL therapy (extracorporeal shock-wave lithotripsy)]. / Diagnostik von Obstruktion und Steinabgang nach ESWL-Therapie.

78 patients with ureteral formations of stone fragments after ESWL therapy have been controlled by both ultrasound and plain abdominal films. Detection of renal stone fragments was possible similarly by sonography or radiographs. The plain films demonstrated well location and length of the "Steinstrasse", which did not necessarily cause obstruction. Combination of sonography and plain abdominal film allows an easy follow-up after ESWL therapy, so i.v. urogramm is not aquired routinely.

[The technical requirements for percutaneous fine-caliber cholangioscopy. Experimental experiences with an animal model]. / Technische Bedingungen der perkutanen Feinkalibercholangioskopie. Experimentelle Erfahrungen im Tiermodell.

A total of 115 percutaneous fine-calibre cholangioscopies were performed in an animal model, using different types of fine-calibre cholangioscopes of 0.8 to 2.8 mm. diameter. Additional properties of single endoscopes included different flexibility, deflectability of the tip, occlusion balloon and working channel. Due to the low steerability of the instruments used, a coaxial guidance by an introducing sheath was mandatory for sufficient imaging quality. Besides flexibility and provision of a working channel, no other properties contributed to a successful endoscopic inspection of the biliary system.

[Transbrachial selective carotid DSA in outpatients: safety and efficacy]. / Diagnostische Sicherheit und Effizienz ambulanter transbrachialer selektiver Karotisangiographien.

PURPOSE: To describe safety and efficacy of transbrachial selective carotid digital subtraction angiography (DSA) in outpatients. MATERIALS AND METHODS: From July 1999 to November 2001, selective carotid angiography was performed in 141 outpatients preferably using a left brachial arterial approach. The average age of the patients was 68 years (range: 39 - 89 years). After flush aortography through a 4F-pigtail catheter, bilateral selective common carotid artery (CCA) catheterization was performed with 4F-Sidewinder-1 or Sidewinder-2 catheters. In 49 patients, Doppler-sonography was performed before or after arteriography. A total of 41 patients underwent carotid surgery. RESULTS: Selective catheterization of the CCA was successful in 96 % of the cases. The diagnostic quality of the opacified aorta and CCA images was good to excellent. The overall complication rate did not exceed 2.1 %, and severe complications were not observed. One patient showed transient neurological symptoms and another mild nausea and agitation, probably as toxic reaction to the contrast medium. A single local hematoma developed after unsuccessful puncture of the brachial artery. CONCLUSION: Transbrachial selective carotid DSA is safe, reliable and well-tolerated in outpatients and achieves a superimposition-free CCA visualization.

[Simple localization of peripheral pulmonary nodules - CT-guided percutaneous hook-wire localization]. / Einfache Lokalisation von intrapulmonalen Rundherden - CT-gesteuerte perkutane Hakenmarkierung.

BACKGROUND: Video-assisted thoracoscopic surgery (VATS) is an alternative approach to small intrapulmonary nodules, if transbronchial or percutaneous biopsy have failed. We investigated the feasibility and effectiveness of the percutaneous CT-guided placement of hook-wires to localize such nodules before video-assisted thoracoscopy. SUBJECTS AND METHODS: 19 patients with new by diagnosed intrapulmonary nodules underwent CT-guided hook-wire localization by application of a X-Reidy -Set (Cook, Inc., Bjaeverskov, Denmark). The average age of the patient was 63 years (range: 19 - 80 years), the mean distance between the nodule and the pleura visceral was 7.58 mm (range: 0 - 25 mm) and the mean diameter was 11.58 mm (range: 5 - 25 mm). After localization, the patients underwent a VATS resection of the lesion within a mean time of 30 min (range 10 - 48 min). RESULTS: In all cases, resection of the nodules was successful. In 4 older patients the marking was complicated by poor cooperability. At the end of manipulation the end of the hook was distanced from the nodule. But also in these cases, resection was successfully performed. 8 patients developed an asymptomatic pneumothorax: 5 of them in a minor (max. 1.5 cm rim), three of them in a moderate (max. 3 cm rim) dimension. In 4 patients, in whom the tumor was hit directly by the needle, local bleeding occurred. In one case, haemoptoe was present. In no patient did a dislocation of the hookwire-system occur. CONCLUSION: CT-guided placement of a hook-wire system is a simple and reasonable procedure which facilitates safe VATS resection of small pulmonary nodules.

[Color-coded duplex sonography (angiodynography) in the evaluation of arteriovenous shunts]. / Farbkodierte Duplexsonographie (Angiodynographie) in der Beurteilung arteriovenöser Shunts.

In 21 hemodialysis patients colour coded duplex sonography (angiodynography) was performed on 23 av-fistulae. In all patients topographic shunt pathways could be evaluated sufficiently, which corresponded well to digital subtraction angiography, that was available in a number of cases. Pathology could be easily identified by morphologic tissue changes in combination with altered flow patterns. The advantage of angiodynography in av-fistulae is a combined information about both morphology and flow dynamics, which can be won in an absolutely noninvasive manner.