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Biomedical subjects

D Liermann

Publications and source records attributed to D Liermann.

52 records · Page 3Linked to original sources
PubMed1989

[Rotational angioplasty--recanalization of chronic arterial occlusion using a slowly rotating catheter. Clinical results with 100 patients].

Between December 1986 and January 1989, 100 patients with chronic occlusions of peripheral arteries were treated with the new technique of low speed rotational angioplasty. This uses a relatively thick, flexible and blunt catheter, which is driven by an electric motor (100 to 200 r.p.m.). The success rate in the superficial femoral and popliteal arteries of the initial intervention for occlusions less than 10 cm was 90%, for occlusions of less than 10 cm, it was 80%. Occlusions on which conventional techniques had failed were successfully recanalized in 65%. Recanalisation was also successful in seven out of 12 patients with occluded iliac arteries. There were no perforations or other serious complications. It is concluded that the new method is particularly effective and safe for recanalisation of chronic vascular occlusions and should also be considered for cases which previously could only be treated surgically.

Adult↗
PubMed1989

[Rotation angioplasty--clinical experiences in 83 patients with chronic arterial vascular occlusion].

Chronic, total vascular occlusion represents the limit for use of balloon dilatation. Occlusions of the superficial femoral artery and popliteal artery of more than 10 cm in length have a low recanalization rate of 50 to 60% with conventional angioplasty. In iliac artery occlusions, in addition to a high rate of complications, the recanalization rate is only about 30 to 40%. Starting in 1984, we developed a slowly rotating (100 to 200 r.p.m.), electrically-driven, flexible catheter with a blunt tip, inside lumen and outer diameter of 2.2 mm for the purpose of recanalization (Figure 1). The theoretical basis was that such a catheter would seek the soft occluding thrombus as the path of least resistance. Since 1986, the procedure has been carried out in 56 patients with occlusion of the superficial femoral artery, 21 with occlusion of the popliteal artery and six with occlusion of the iliac artery. The duration of occlusion ranged between five and 48 months and the length of the occlusions between 5 and 35 cm (mean 12.5 cm); the patients were in Fontaine stage II and IV, the ankle arm-index ranged between 0 and 0.86 (mean 0,51). After antegrade or retrograde puncture of the common femoral artery and intra-arterial injection of 5,000 units of heparin, the rotation catheter was advanced through an 8F sheath through the occlusion by means of slow rotation (Figure 2). After contrast medium injection to document the intraluminal position of the catheter and the catheter exchange over a 0.35'' wire, the channel created was dilated.(ABSTRACT TRUNCATED AT 250 WORDS)

Aged↗
PubMed1988

Results of low speed rotational angioplasty for chronic peripheral occlusions.

After experimental investigation using postmortem human arteries, 19 patients with chronic peripheral artery occlusions were treated with a new angioplasty technique between December 1986 and October 1987. In 17 patients the superficial femoral artery and in 2 patients the popliteal artery were completely occluded. The length of the occlusions ranged between 5 and 25 cm (mean 11). The duration--estimated according to patients' history--was 5 to 48 months (mean 17). In 5 patients, durations of up to 30 months had been documented by angiography. A flexible, blunt, motor-driven rotating catheter was introduced through an 8 or 9Fr sheath and rotational angioplasty was performed at low speeds (up to 200 rpm). In 11 of 14 patients in whom this new technique was used as the primary intervention, the occlusions could be successfully reopened. In 2 patients after failure of conventional techniques the rotating catheter could not bypass the preexisting dissections in the same intervention. In 2 of 3 further patients after failure of conventional techniques the occlusions could be successfully reopened in a second intervention after several weeks. In none of the 19 patients did a perforation occur. It is concluded that with the new technique chronic peripheral artery occlusions can be reopened with a high success rate and without the danger of arterial wall perforation. The method can also be used in patients in whom conventional techniques have failed.

Adult↗
PubMed1988

[Rotation angioplasty--initial clinical results of peripheral vascular occlusions].

After experimental investigations in postmortem human arteries, 19 patients with chronic peripheral artery occlusions were treated with a new technique between December 1986 and October 1987. In 17 patients the superficial femoral artery, and in two patients the popliteal artery, was completely occluded. The length of occlusions were between 5 and 25 cm (mean 10.9 cm); the duration (estimated according to patient's history) was 5-48 months (mean 17.2 months). In five patients, durations of up to 30 months had been documented by angiography. A flexible, blunt, motor-driven rotating catheter was introduced over an 8 or 9 F sheet and rotational angioplasty was performed at low speed, up to 200 rpm. In 11/14 patients in whom this new technique was used as the first attempt, the occlusions could be successfully reopened. In two patients after failure of the conventional technique the rotating catheter could not bypass the preexisting dissections in the same intervention. In 2/3 further patients after failure of the conventional technique the occlusions could be successfully reopened in a second intervention after several weeks. In none of our 19 patients did a perforation occur. It is concluded that by using the new technique, chronic peripheral artery occlusions can be reopened with a high success rate and without the danger of vessel wall perforation. The method can also be applied in patients in whom conventional techniques have failed.

Adult↗
PubMedDate not supplied

Iliac and femoropopliteal vascular occlusive disease treated with flexible tantalum stents.

Two hundred patients were treated with tantalum stents, 2 in the aortoiliac bifurcation, 114 in the iliac, and 84 in the femoropopliteal arteries. The indications for stenting were technically unsuccessful percutaneous transluminal angioplasty (PTA) due to arterial recoil, dissection (156 patients), or acute occlusions (15 patients). Long iliac artery occlusions (29 patients) were indications for primary stenting. Life-table analysis revealed a 3-year patency rate of 95% for stented iliac arteries, and a 1-year patency rate of 80% for stented femoropopliteal arteries. Restenosis of the stented femoropopliteal lumen was particularly frequent in stents placed for restenosis following prior PTA (7 of 12 patients), in stents placed into the distal superficial femoral and popliteal arteries (14 of 24 patients), and in stents positioned over a longer than 4-cm artery segment (9 of 16 patients). For the aortic bifurcation and iliac arteries, arterial stenting has proved to be a valuable adjunct to PTA; for femoropopliteal arteries, stenting should be restricted to acute arterial occlusions or severe residual stenosis following PTA.

Adult↗
PubMedDate not supplied

The Strecker stent: indications and results in iliac and femoropopliteal arteries.

We have implanted more than 100 Strecker stents in the iliac and femoral arteries. In iliac arteries, follow-up is available from 8 to 48 months (mean 20 months) and in peripheral arteries, from 8 to 32 months (mean 19 months). In iliac and proximal femoral arteries there was a patency rate of 98% (mean 20 months after stent implantation) whereas in peripheral arteries the patency rate was 70.8% (mean 19 months after stent implantation). Besides careful selection of patients, anticoagulation is very important for successful stenting. Because of the excellent results of stents in iliac vessels there is a wide range of good indications, including primary stenting after recanalization of occlusions. In contrast, stent implantation in peripheral vessels should be restricted to special cases such as acute dissection or reocclusion after successful recanalization.

Anticoagulants↗
PubMedDate not supplied

CT fluoroscopy-guided abdominal interventions.

Computed tomographic fluoroscopy (CTF) is one of the most recent developments in helical computed tomography (CT), which is increasingly being used in interventional radiology. The method combines the advantages of CT with the real-time capabilities of ultrasonography. This article reviews the current clinical applications of CTF in the monitoring of abdominopelvic interventions with reference to published clinical studies.

Biopsy, Needle↗
PubMedDate not supplied

First experiences in CT-guided percutaneous transhepatic biliary decompression by means of real-time CT fluoroscopy.

BACKGROUND: Computed tomographic fluoroscopy (CTF), also called real-time CT, is increasingly used in interventional radiology but has not yet been recommended to guide percutaneous transhepatic biliary decompression (PTBD). We report our early clinical experiences with CTF-guided PTBD. METHODS: Sixteen consecutive patients underwent PTBD under CTF guidance because of obstructive jaundice caused by malignant tumor (11 cases of carcinoma of the bile duct, four cases of pancreatic cancer, and one case of metastasis). CTF-guided PTBD was performed on a helical CT scanner and a surgical C arm. Main target parameters were the success and complication rates, the number of necessary punctures, the time needed for successful puncture of a suitable bile duct, and the patients' radiation exposure. RESULTS: CTF-guided punctures of the bile duct for PTBD were successful on the first trial in 10 cases; in six patients, two hits were necessary. The time needed to hit a suitable bile duct was 6-21 s (median = 13 s). Therefore, the radiation exposure (skin) was 27-94.5 mSv. The additional implantation and stenting of the bile duct by means of the surgical C arm was uneventful in 15 cases. In one case, only external drainage could be achieved. Complications did not occur. CONCLUSION: CTF enables good visualization of the most suitable duct for puncture. Therefore, subsequent recanalization seems to be easier than other methods.

Bile Duct Neoplasms↗
PubMedDate not supplied

A comparative study of CT fluoroscopy combined with fluoroscopy versus fluoroscopy alone for percutaneous transhepatic biliary drainage.

PURPOSE: We compared CT fluoroscopy (CTF) for the initial puncture of bile ducts with conventional fluoroscopic guidance in patients with malignant jaundice in whom percutaneous transhepatic biliary drainage (PTBD) was planned. METHODS: Forty consecutive patients were randomized to two study groups: group A underwent PTBD under CTF and fluoroscopic guidance, group B underwent PTBD under fluoroscopic guidance alone. CTF-guided PTBD was performed using a combination of a helical CT scanner of the latest generation and a mobile C-arm; conventional PTBD was performed under fluoroscopic guidance in the angiographic unit. End points of the study were the success (a puncture that enabled safe placement of a guidewire in a suitable bile duct) and the complication rate (hemobilia, bile fistula, biliary peritonitis), the number of punctures required, the time needed for successful puncture of a suitable bile duct, and the patient's radiation exposure. RESULTS: CTF-guided puncture of peripheral bile ducts suitable for PTBD was successful at the first attempt in 16 cases, under conventional fluoroscopic guidance, in only two cases. We found a significantly different number of punctures (1.2 in group A vs 2.9 in group B), a significantly shorter time for puncture in group A (mean 39 sec), but also a significantly higher skin exposure dosage in group A (mean 49.5 mSv surface dosage). There was no significant difference regarding the total procedure time. Only one complication occurred in group B (portobiliary fistula). CONCLUSION: CTF-guided initial puncture of bile ducts allowed a significantly reduced number of punctures and puncture times compared with puncture under conventional fluoroscopic guidance for placement of percutaneous transhepatic biliary drainage catheters.

Adult↗
PubMedDate not supplied

Better visualization of transbronchial biopsy using CT fluoroscopy.

PURPOSE: Computed tomography fluoroscopy (CTF) provides the capability for continuous CT imaging and has been increasingly used in interventional procedures. Our objective was to assess the usefulness of CTF in the monitoring of transbronchial biopsy procedures. METHODS: We evaluated nine patients in whom yield of "conventional" transbronchial biopsies had failed. CTF was performed on a Somatom Plus 4 Power scanner (CARE Vision CT, Siemens, Forchheim, Germany) using 120 kV, 50 mA at a frame rate of eight images per second on a matrix of 256 x 256. Image reconstruction was based on a partial scan with an acquisition time of 0.5 sec. The maximal time without interruption was 79 sec; after stopping for a few seconds a new period of 79 sec was available. The number of biopsies, procedure times, applied dose, and histologic results were documented. RESULTS: With CTF-guided transbronchial biopsy, the yield of the biopsies was improved. In seven patients biopsy yielded bronchial cancer; in one patient histopathologic examination showed tuberculosis. Only in one patient did CTF-guided transbronchial biopsy fail. The mean number of biopsies was four in each patient. Mean fluoroscopy time was 165 +/- 92 sec (range 111-272 sec) and mean procedure time was 800 +/- 302 sec (range 480-1081 sec). The applied dose ranged between 500 and 1224 mSv; the mean applied dose was 743 +/- 414 mSv. There were no fatal complications. CONCLUSION: Computed tomography fluoroscopy appears to facilitate visualization of transbronchial biopsy procedures, with the drawback of increased radiation exposure. To compare the "conventional" method versus CTF a randomized prospective study is necessary.

Aged↗
PubMedDate not supplied

First experiences in percutaneous arterial chemoembolization of malignant liver lesions by means of real-time CT fluoroscopy.

Computed tomography fluoroscopy (CTF) allows real-time display (continuous imaging) and has been increasingly used in interventional procedures. We wished to demonstrate the usefulness of CTF in chemoembolization of the liver. Twenty-one patients with primary or secondary malignant lesions of the liver underwent CTF-guided chemoembolization after angiographic positioning of a catheter in the hepatic artery. Embolization materials such as Lipiodol and mitomycin C were administered under continuous CT scanning. CTF led to a change of the method (correction of catheter position, application of norepinephrine) in nine of 21 cases. There were no fatal complications.

Aged↗
PubMedDate not supplied

CTF-guided puncture of an unenhanced isodense liver lesion during continuous intravenous injection of contrast medium.

CT fluoroscopy (CTF) facilitates guidance of percutaneous biopsies and other interventional procedures. We wished to demonstrate the usefulness of CTF for the puncture of an unenhanced isodense liver lesion during continuous injection of intravenous contrast medium. We performed CTF-guided puncture of a 2-cm lesion in the liver of a patient suffering from lung cancer. CTF enables puncture of liver foci even if they are unenhanced and isodense with the surrounding parenchyma.

Contrast Media↗
PubMedDate not supplied

[Origin and course of renal arteries. A CT study for determining optimal projection plane in renal artery angiography].

In an attempt to optimize renal artery angiography we performed a CT-study. In 500 patients we determined the angle at which the arteries arise from the aorta and their course. Both renal arteries are in one plane, which is tilted 13 degrees ventrally on the right and 13 degrees dorsally on the left. More distally we found an angle of 35 degrees on the right and an angle of 29 degrees on the left in the dorsal direction. These findings were independent of age and sex of the patient.

Adolescent↗
PubMedDate not supplied

Prophylactic endovascular radiotherapy to prevent intimal hyperplasia after stent implantation in femoropopliteal arteries.

PURPOSE: Recurrent stenosis or occlusion by intimal hyperplasia occurs in up to 40% of patients with tantalum stent implantations in femoropopliteal arteries and greatly restricts their usefulness. We evaluated the effect of prophylactic endovascular radiotherapy on stenosed/occluded stents. METHODS: We investigated prophylactic endovascular radiotherapy with a surface dose of 12 Gy using an iridium 192 source as a means to reduce or eliminate recurrent stenosis in 4 patients with stenosed/occluded stents, 6-8 months after the original implantation. Confirmatory diagnostic atherectomy, PTA or laser recanalization and endovascular radiotherapy were performed. RESULTS: None of the four has developed recurrent obstruction within 23 to 30 months after this treatment, which up to now shows no short-term or long-term complications. CONCLUSION: We conclude that this limited experience is promising enough to warrant further study.

Aged↗