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Biomedical subjects

J Lammer

Publications and source records attributed to J Lammer.

At least 91 records · Page 5Linked to original sources
PubMed1990

[Percutaneous transluminal balloon valvuloplasty and balloon angioplasty in congenital heart defects with left heart obstruction in childhood].

Balloon dilation was performed in 31 patients with congenital left heart obstructions. In 16 patients with aortic stenosis aged 2 days to 16.3 years (mean 10.03 +/- 4.79 years) the peak systolic gradient decreased significantly from 80 +/- 21 mmHg to 23 +/- 13 mmHg immediately after dilation, and remained low at the time of follow up (6 months to 3 years), namely 30 +/- 12 mmHg (p less than 0.0001). Mild aortic regurgitation (I degrees) was already present before the procedure in 56%, increased in 3 patients, and reached haemodynamic significance in 1 (III degrees). Half of the 14 patients with coarctation, aged 2 months to 16.75 years (mean 4.98 +/- 5.15 years), had undergone previous surgery 2 months to 7.9 years before the balloon dilation; coarctation was native in the remainder. Peak systolic gradient across the coarctation site was reduced from 46 +/- 10 mmHg to 5 +/- 5 mmHg, and was 9 +/- 7 mmHg at the time of follow up (6 months-3.6 years) (p less than 0.0001). Aneurysms were not detected. In a 6-year-old girl with congenital mitral stenosis the gradient fell from 13 mmHg to 7 mmHg immediately after the procedure. There were no serious complications. Peripheral arterial lesions required medical or surgical treatment in 16% of cases. Our report suggests that balloon valvuloplasty and angioplasty is a safe and well-tolerated procedure in childhood. It can reduce the gradient in congenital left heart obstructions with good short-term and intermediate-term results.

Adolescent↗
PubMed1990

Renal cell carcinoma presenting as spontaneous retroperitoneal haemorrhage.

On the basis of a spontaneous retroperitoneal haematoma in a 55-year-old female patient the diagnostic and therapeutical problems of such an emergency situation will be discussed. Due to the high incidence of malignant tumours as the bleeding source, radical surgery becomes the necessary treatment, which may be needlessly burdened by high operative risk in the acute phase. For that reason the mode of treatment chosen in this particular case was immediate embolization subsequent to arteriography along with consecutive extracapsular nephrectomy and removal of the haematoma.

Carcinoma, Renal Cell↗
PubMed1990

Obstructive jaundice: use of expandable metal endoprosthesis for biliary drainage. Work in progress.

Expandable metal endoprostheses were implanted transhepatically in 61 patients with obstructive jaundice. Fifty-three patients had malignant and eight had benign obstructions. Because of the small diameter of the compressed stent (7 F), primary implantation of the stent without a previous catheter drainage was preferred. Postprocedural complications occurred in three patients (5%) (biliary pleuritis, peritonitis, hepatic artery aneurysm). The 30-day mortality rate was 8.2%. Reocclusions were observed in six of the patients with malignant obstructions (11%) (observation period, 1-10 months; mean, 4.5 months) and in two of the patients with benign stenoses (25%) (observation period, 3-21 months; mean, 9 months). The higher reocclusion rate of benign obstructions must be interpreted with care because of the small number of patients. From their preliminary experience, the authors conclude that expandable metal endoprostheses offer patency rates equal to those of plastic stents. The implantation trauma is reduced due to the small 7-F introducing catheter system.

Bile Ducts↗
PubMed1990

[Primary and secondary inoperable teratoid hepatoblastoma--multidisciplinary management].

Hepatoblastomas are the most frequent malignant liver tumors of childhood. Prognosis mostly depends on their resectability. Unresectable tumors are almost invariably fatal, unless their size can be decreased by chemotherapy and/or irradiation to permit surgical removal. In the present case report we discuss the clinical course of a 15 months old boy, who was admitted with primary inoperable teratoid hepatoblastoma. After alternating intravenous and intraarterial chemotherapy as well as radiation therapy, the tumor could be successfully resected. Specific problems of histological diagnosis and of the therapeutic management are discussed, and an overview of the recent literature in behalf of the histological basis, therapeutic possibilities and prognostic factors of hepatoblastomas is given.

Antineoplastic Combined Chemotherapy Protocols↗
PubMed1990

[Femoropopliteal laser recanalization--a multicenter study].

Laser-assisted angioplasty was performed in four different hospital centers, following the same treatment protocol and using an Nd-YAG laser with a sapphire-probe catheter. The initial recanalization rate of 259 femoro-popliteal occlusions with a mean length of 7.5 cm was 84%. Dissections or perforations were observed in 10%. An emergency surgical intervention was required in 1.1%. The long-term patency rate of the successfully recanalized arteries was 74% after 2 years. The cumulative cure rate of all 259 patients was 62%.

Adult↗
PubMed1990

Biliary endoprostheses. Plastic versus metal stents.

Plastic biliary endoprostheses relieved malignant obstructive jaundice in 80% to 90% of the patients. The comfort of a completely indwelling endoprosthesis should be offered to all palliatively treated tumor patients, and external-internal catheters should be reserved for the minority of patients who return with reoccluded endoprostheses. These patients have bacterial flora that rapidly contaminates the endoprosthesis and causes encrustations and reocclusions. Thus, a second endoprosthesis also would reocclude quickly. The mechanism of reocclusion of plastic and metal endoprostheses is completely different. In plastic endoprostheses, bacterial contamination causes decomposition of the bile and subsequent encrustation. In metal endoprostheses tumor ingrowths between the struts of the stent cause reocclusion. Tumor ingrowths were observed in only 6.5% of metal prostheses with a narrow woven mesh (Wallstent), whereas prostheses with large distances between the struts (Gianturco stent) had ingrowth rates of 19% to 50%. This fact shows that tumor ingrowths can be reduced by narrowing the spaces between the metallic network, and, therefore, improvements in the design of the metal stents should reduce the occlusion rate to or below that of plastic endoprostheses, which currently have a lower encrustation rate. The major advantages of expandable metal prostheses are the relative ease and the minimal trauma of the implantation procedure. The Wallstent endoprosthesis, in particular, can be inserted through a 7-F introducer sheath and offers the chance of single-step placement. The 30-day mortality rate, therefore, was only 5%. This is significantly lower than the 30-day mortality rate after insertion of plastic prostheses (15% to 24%). Even simple external catheter drainage procedures have a higher reported 30-day mortality rate (27%). Expandable metal endoprostheses would be the most useful device if the occlusion rate could be kept under 10% in large series. Increasing the length of the endoprostheses to 10 cm in the expanded state could also improve the long-term patency rates.

Bile Ducts↗
PubMed1989

[Management of acute intrathoracic aortic dissection].

At the intensive care station of the Internal Medicine Department, University Clinic Graz, all patients admitted were promptly and carefully examined in case of suspected acute intrathoracic aortic dissection and immediately treated. In 1987 a total of 4446 patients were referred to this CCU, 893 suffered from acute thoracic pain. In 21 patients of the latter a clinical suspicion of aortic dissection was observed. In 9 patients of these, diagnosis could be established within 5 hours by echocardiography, CT and angiography. 11 patients had no dissection while one positive finding could only be determined by postmortem exam. Retrospectively, these figures for 1982 were 3908 admitted patients, 790 suffering from acute thoracic pain of which only 5 showed suspected dissection. In 3 cases dissection could be confirmed using the same diagnostic procedures, but 2 were without finding. Further 3 patients out of the total series were affected with dissection which could only be determined postmortem. Out of the 9 patients with positive diagnosis, 6 showed Typ I, 1 Typ II and 2 Typ III dissection according to DeBakey (8m, 1f, range 46-78 years). 2 patients underwent surgery immediately after diagnosis, 1 after 12 hours, while 4 cases were conservatively treated. These 7 patients have survived by controlled hypotension up to now (10 to 22 months). Two patients died 2 and 10 hours, respectively, after admission with positive diagnosis. In spite of the severity of this disease prompt and efficient diagnosis and rapid therapeutic management are the key to survival.

Aged↗
PubMed1989

Contact probes for intravascular laser recanalization. Experimental evaluation.

Experimental laser ablation of atheromatous plaques was performed with a bare quartz glass fiber, a metal probe, and a sapphire probe. The tissue response after irradiation with increasing energies was evaluated by means of light and scanning electron microscopy. Laser emission through the bare fiber caused a narrow, deep crater with an irregular surface surrounded by a zone of thermal necrosis. After tissue ablation with the metal probe, a disproportion between the small tissue defect and the large zone of thermal necrosis was observed. The largest tissue defect was vaporized by the sapphire contact probe. A small zone of thermal necrosis surrounded the laser crater.

Arteries↗
PubMed1989

[Current state and perspectives of laser use in vascular surgery].

We report on a project to determine the feasibility of treating carotid artery stenosis with the argon laser (1985) and the clinical results of recanalising peripheral arteries. Training for the above-mentioned project showed that sapphire-tipped Nd:YAG laser optical fibers are the proper instruments for recanalisation. New attempts with new catheter material should make the recanalisation of the carotid artery possible in the future.

Adult↗
PubMed1988

Preoperative angiography in reconstructive microsurgery of the maxillofacial region.

The value of preoperative angiography of the donor and recipient sites in the reconstruction of the head and neck is reported. After neck-dissection an angiographic study of the carotid artery is routinely carried out as the vascular anatomy of the donor site can be determined only by angiography once surgery has been carried out. Angiography indicates not only the possible location for the planned microsurgical anastomosis, but also the potential difficulties which can arise from kinking and other changes in the vessel wall. The operative time can be reduced also by better preoperative planning of the best anastomotic sites.

Anastomosis, Surgical↗
PubMed1988

Laser angioplasty with a contact probe for the treatment of peripheral vascular disease.

Percutaneous transluminal laser angioplasty was carried out for the dilatation of 30 completely occluded peripheral arterial segments and three subtotal stenoses. A neodymium-YAG laser and an optical fibre delivery system with a sapphire tip were used. All three arterial stenoses and 26 of the 30 occluded arterial segments were successfully dilated. In 20 patients additional dilatation was carried out with a balloon catheter. Laser angioplasty failed to recanalise four occlusions, and vessel leakage without clinical consequences occurred in one patient. Reocclusion occurred within 48 h in two patients and after five months in one patient during a follow up period of at least six months. It is concluded that percutaneous transluminal laser angioplasty using direct contact with a sapphire tip is highly effective (89% success rate) in reopening peripheral vascular occlusions. The procedure is safe, and reocclusion of vessels is rare during the six month follow up period.

Adult↗
PubMed1988

Intraluminal stents in atherosclerotic iliac artery stenosis: preliminary report of a multicenter study.

Fifteen patients with symptomatic iliac artery stenosis were treated with intraluminal placement of balloon-expandable stents. Before treatment, 14 patients had intermittent claudication, and one had a limb at risk for amputation. One patient had diabetes mellitus, nine had hypertension, and all were long-term smokers. Two patients had surgical placement of the stent; in one patient this was part of a combined revascularization procedure. All other stents were placed percutaneously. The transstenotic gradient after injection of vasodilating drugs distal to the lesion decreased from a mean of 32.3 mm Hg +/- 16.7 to 3.1 mm Hg +/- 4.2 after stent placement. Ankle-arm Doppler systolic pressure index increased from a mean of 0.68 +/- 0.22 to 0.96 +/- 0.24 after the procedure. The treatment eliminated intermittent claudication in 14 patients and increased exercise tolerance to 500 m in the patient with a limb at risk for amputation before the procedure. The improved condition persisted in all patients during the follow-up of 6-12 months. Stent placement may be a valuable adjunct in the management of iliac artery disease.

Angiography↗