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Biomedical subjects

J Lammer

Publications and source records attributed to J Lammer.

At least 73 records · Page 4Linked to original sources
PubMed1994

Iliac artery stent placement: clinical experience with a nitinol stent.

PURPOSE: To determine the effectiveness of a prototype nitinol stent in the iliac arteries. MATERIALS AND METHODS: Fourteen patients with arteriosclerotic lesions of the iliac arteries (nine stenoses, five occlusions) were treated percutaneously with a prototype nitinol vascular stent (Cragg stent) after unsuccessful percutaneous transluminal angioplasty. RESULTS: In 13 patients available for follow-up, the mean ankle-brachial index (ABI) increased from 0.4 +/- 0.32 (standard deviation) before the procedure to 0.81 +/- 0.27 after the procedure (P < .01). After 6, 12, and 24 months, the mean ABI was 0.97 +/- 0.2, 0.87 +/- 0.15, and 0.89 +/- 0.1, respectively. In two patients, radial stiffness of the stent was too low to completely eliminate a high-grade, calcified stenosis; long-term patency of the vessel, however, was preserved. In all other patients, stent placement achieved good vascular reconstitution. No stent occlusion or restenosis was observed. CONCLUSION: The results with the Cragg stent were similar to those with other commercially available stents. These preliminary results require confirmation with a larger series.

Aged↗
PubMed1994

Determination of optimal time window for liver scanning with CT during arterial portography.

PURPOSE: To determine the optimal time window for scanning the liver with computed tomography (CT) during arterial portography (CTAP). MATERIALS AND METHODS: After vasodilation and contrast medium injection into the superior mesenteric artery (80 mL at 5 mL/sec), 25 repeated scans were obtained at a single level within 83 seconds in 13 patients. Attenuation was measured on every scan, and time-attenuation curves were created. Enhancement characteristics of the portal vein, liver parenchyma, aorta, and tumors were evaluated. RESULTS: Parenchymal enhancement of more than 60 HU was achieved between 18 seconds +/- 4 (standard deviation) and 67 seconds +/- 15, and high parenchyma-to-tumor contrast of more than 50 HU occurred between 18 seconds +/- 3 and 62 seconds +/- 14. CONCLUSION: To scan the liver within such a narrow time window, a spiral CT technique is necessary. When the above injection parameters are used in CTAP, the spiral CT sequence should be started 20 seconds after the beginning of the injection.

Adult↗
PubMed1994

Doppler sonography of varicocele: long-term follow-up after venography and transcatheter sclerotherapy.

Sixty-eight patients with unilateral left-sided idiopathic varicocele who had not been treated previously were examined with Doppler sonography before and 1, 3, and 12 months after selective venography with balloon occlusion and transcatheter sclerotherapy of the internal spermatic vein. Varicocele and its persistence or recurrence was diagnosed by reflux only. Reflux was differentiated into stop-type and shunt-type by Doppler sonography. The resolution of varicocele was defined by absence of any reflux. The rate of resolution was greatest 3 months after sclerotherapy (49 patients, 72%). The diagnosis of persisting or recurring varicocele at this time does not seem to be justified, however, as in our study both further improvement and deterioration were observed up to 12 months after treatment. Twenty patients (29%) had a persisting or recurring varicocele 12 months after sclerotherapy. Reflux is the parameter of significance for diagnosing varicocele and its persistence or recurrence after therapy. Improvement of clinical aspects of varicocele (e.g., sperm count, sperm motility, and conception rates) depends on therapy of even subclinical varicoceles. Therefore, diagnosis and retreatment of persistent or recurrent varicoceles seems essential. The high sensitivity of Doppler sonography permits adequate assessment of the therapeutic result and evaluation of real rates of persistent or recurrent varicoceles after venography with balloon occlusion and transcatheter sclerotherapy.

Adult↗
PubMed1993

[Doppler ultrasound of the saphenous vein as a bypass. Detection of arteriovenous fistulae].

In 13 patients who underwent a femorodistal revascularisation with an in situ saphena vein graft and who had been operated on by angioscopic technique, intraoperative angiography and postoperative colour-coded Doppler sonography and i.v./i.a. digital subtraction angiography (DSA) were performed to detect arteriovenous fistulas (AV fistulas). In intraoperative completion angiography no AV fistulas were seen. Colour-coded Doppler sonography and DSA studies performed three to five days postoperatively revealed AV fistulas in 8 patients. The fistulas could be exactly located by sonography, and, if confirmed haemodynamically significantly by i.v./i.a. DSA, they were marked on the skin and ligated. In the detection of AV fistulas in in situ saphenous vein grafts operated by angioscopic technique colour-coded doppler sonography and i.v./i.a. DSA showed equivalent results. In the detection of connections of AV fistulas to the deep draining veins the i.v./i.a. DSA was superior.

Aged↗
PubMed1993

A simplified procedure for intra-arterial thrombolysis with tissue-type plasminogen activator in peripheral arterial occlusive disease: primary and long-term results.

One-hundred and fifty patients with thrombotic and 60 patients with embolic occlusions of the superficial femoral and/or popliteal artery underwent a simplified IAT (intra-arterial thrombolysis) procedure. Ten mg rt-PA combined with 3000 IU Heparin were infused over 6 h, thereafter the extent of thrombolysis was checked fluoroscopically and the above mentioned treatment course repeated up to four times if necessary. The IAT regimen employed did not involve mechanical recanalization attempts; if complete thrombolysis revealed an underlying stenosis, a PTA (percutaneous transluminal angioplasty) was subsequently performed. IAT resulted in complete recanalization of 88 thrombotic occlusions (59%; 95% confidence interval: 50.8%-66.8%) and of 53 embolic occlusions (88%; 95% confidence interval: 77.1%-94.8% P < 0.001). In a further 33 (22%) thrombotic and four (7%) embolic occlusions IAT reduced the length of the occluded segment. At discharge, 102 (67%) patients with thrombotic and 55 (92%) patients with embolic occlusions were clinically improved. Overall, untoward effects occurred in 60 patients (29%): 47 (22%) were minor. Four patients (2%) suffered a systemic haemorrhage (three gastrointestinal, one macrohaematuria). The cumulative potency rate was significantly higher in patients with embolic occlusions throughout follow-up (82% vs 49% for thrombotic occlusions at 2 years, P < 0.001). Although all amputations were carried out in patients with thrombotic occlusions, follow-up mortality did not differ significantly between patients with embolic and thrombotic occlusions.

Adult↗
PubMed1993

Malignant ureteral obstruction: preliminary results of treatment with metallic self-expandable stents.

Self-expandable metal stents 7 mm in diameter were percutaneously implanted into 13 ureters in 10 patients with malignant ureteral obstruction not amenable to double-J stent placement. In nine ureters, one stent was placed, and in four ureters, two overlapping stents were placed. Primary reconstitution of ureteral patency was achieved in all ureters. After 1-2 weeks, four ureters showed a urothelial reaction encroaching on the lumen of the ureter, and a double-J stent was placed coaxially. One ureter was occluded by urothelial hyperplasia 4 weeks after stent placement, and a double-J stent was therefore placed. One ureter was occluded 8 months after stent placement by distal tumor overgrowth. The other ureters showed no signs of obstruction during a follow-up of 3-14 (average, 5.8) months. Peristalsis was preserved at both ends of the stent in all ureters. The use of this stent alone or in combination with a double-J stent alleviated upper urinary tract obstruction and avoided external drainage in all patients.

Adult↗
PubMed1992

Pulsed excimer laser versus continuous-wave Nd:YAG laser versus conventional angioplasty of peripheral arterial occlusions: prospective, controlled, randomised trial.

Early clinical studies of coronary and peripheral laser angioplasty showed that arterial occlusions could be recanalised by continuous-wave lasers delivered with contact probes and by pulsed lasers applied with multifibre catheters. However, whether laser-assisted angioplasty improves success rates in reopening occlusions and in long-term patency rates is unclear. We have compared the primary recanalisation and long-term patency rates after laser-assisted and conventional percutaneous transluminal angioplasty (PTA) of femoropopliteal artery occlusions in 116 consecutive symptomatic patients (excimer laser 37, Nd:YAG laser 40, PTA 39). Primary recanalisation was achieved in 81 patients (70%). The primary recanalisation rate achieved with the excimer laser was significantly lower than that with the Nd:YAG laser (49% vs 78%, p < 0.01) or with PTA (82%, p < 0.003). The overall angiographic recanalisation rate (primary and secondary recanalisation) after laser and PTA was 89%. After 3 months, clinical improvement was recorded in 76% of patients. Clinical long-term results were available in 94 (91%), and angiographic long-term results in 77 (75%), of 103 successfully recanalised patients. Life-table analysis of the long-term results revealed no significant difference of the restenosis rate between the three treatment groups. The 12-month patency rate was 60% as assessed clinically and 39% as judged by angiography. Primary and secondary recanalisation rates and long-term patency rates were significantly correlated with length of the occlusion. Our results suggest that PTA of femoropopliteal artery occlusions is only indicated if the occlusion is short (< 8 cm) and that laser-assisted angioplasty should only be used after failure of conventional PTA.

Aged↗
PubMed1992

[Metallic mesh endoprosthesis and intraluminal high dose rate 192Ir brachytherapy in the palliative treatment of malignant bile duct obstruction. Initial results].

Since December 1989, 9 patients with inoperable malignant biliary tract obstruction were treated palliatively by a combined modality treatment consisting of placement of a permanent biliary endoprosthesis followed by intraluminal high dose-rate 192Ir brachytherapy. A dose of 10 Gy was delivered in a hyperfractionated schedule at the point of reference in a distance of 7.5 mm of centre of the source. External small field radiotherapy (50.4 Gy, 1.8 Gy per day, 5 fractions per week) was also given in six cases (M/O, Karnofsky greater than 60%). In 9/9 cases an unrestrained bile flow and an interruption of pruritus was achieved, in 78% (7/9) of cases the duration of palliation was as long as the survival time (median survival time 7.5 months).

Adenocarcinoma↗
PubMed1992

Transoesophageal echocardiography during removal of a caval filter in a patient at high risk of massive pulmonary thromboembolism.

A new type of vena caval filter was to be removed from a woman who had a high risk of massive pulmonary thromboembolism because of extensive thrombus in the iliac vein incorporating the filter. The removal was performed under general anaesthesia in the cardiac operating theatre using transoesophageal echocardiography to monitor the right heart and the pulmonary artery during the critical phase of removal. The manoeuvre succeeded with only insignificant embolisation occurring, and that was identified by transoesophageal echocardiography.

Echocardiography↗
PubMed1992

Malignant biliary obstruction: histologic findings after treatment with self-expandable stents.

Histologic analysis was performed of bile duct tissue from 15 patients who underwent treatment for malignant obstructive jaundice with a self-expandable stent. Stents were in place from 5 days to 21 months. Malignancies included adenocarcinoma of the pancreas or gallbladder or cholangiocellular, hepatocellular, or gastric carcinoma. Stents were blocked by sludge in two cases and tumor overgrowth in two others. Microscopic evaluation showed that stent placement caused complete denudation of the mucosa and mild submucosal inflammation with edema. In all but one patient, the stent was incorporated into the bile duct wall and was covered by a fibrogranulomatous tissue layer after 2 months. In some cases, an epithelium-like cell formation covered the inner surface of the stent. Tumor ingrowth was observed in two patients with poorly differentiated tumors. In stents placed for longer than 2 months, mild to moderate fibrosis and foreign body reaction were observed. Hyperplastic biliary epithelium was not found within the stent or at the stent ends.

Adult↗
PubMed1992

Percutaneous transluminal angioplasty of crural arteries.

In 91 patients suffering from peripheral arterial occlusive disease (Fontaine stage IIb-IV) 125 percutaneous transluminal angioplasties (PTA) of crural arteries were performed. Eighty-six of the dilatations were done in combination with a recanalization procedure (PTA, laser angioplasty, fibrinolysis) of a femoropopliteal obstruction in order to improve outflow. PTA was performed with 5 F balloon catheters 2.5 to 4 mm in diameter in combination with steerable guide wires. A primary technical success was achieved in 41 of 42 (97.6%) vessels with a single stenosis, in 64 of 68 (94.1%) vessels with 2 or more stenoses, and 9 of 15 (60%) vessels with total occlusions (overall primary success rate 91.2%). Complications included spasm (n = 3), thrombosis (n = 2), peripheral embolization (n = 2), and dissection (n = 1). None of the complications required surgical intervention. After PTA, accumulative patency rate of 71% at 2 years and 64.2% at 3 years was achieved. These results demonstrated that PTA of crural arteries is a safe procedure with an excellent primary success rate and satisfying long-term results. Thus we believe that even arterial occlusive disease in the clinical stage Fontaine IIb should be accepted as an indication for crural PTA. Furthermore, crural PTA should be used to improve reduced peripheral outflow after femoropopliteal PTA.

Adult↗
PubMed1992

Iliac artery stenting--clinical experience with the Palmaz stent, Wallstent, and Strecker stent.

A total of 82 iliac artery lesions (62 stenoses and 20 occlusions) were treated with 3 different types of endovascular metallic stents (12 lesions with the Palmaz stent, 36 with the Wallstent, and 34 with the Strecker stent). The complication rate was 12%. Occlusion of 2 Wallstents occurred 4 and 12 weeks after stent placement, respectively. Both stents were recanalized by local fibrinolysis. One Strecker stent occluded after 8 months. The observation period was 3 to 26 months (mean 9.7 months). The patency rate with secondary intervention (fibrinolysis) was 100% after 3 and 6 months, and 98% after 9 months. All 3 stent designs turned out to be effective in the treatment of complicated iliac artery occlusive disease.

Adult↗
PubMed1991

[Percutaneous recanalization of pelvic artery occlusions--fibrinolysis, PTA, stents].

In 42 patients with symptomatic chronic iliac artery occlusions with a length of 2-15 cm (mean 4.3 cm), percutaneous recanalization was attempted. The study population was divided into 2 groups: Group I (n = 17) is a retrospective control group, the patients were treated with fibrinolysis (FL) and percutaneous transluminal angioplasty (PTA). In group II (n = 25) the patients were treated according to a prospective protocol including FL, PTA and placement of endovascular self-expandable stents. The recanalization rate for Group I and II together was 83% (35/42). FL was effective in 47%, in 53% the recanalization was performed mechanically only. The patency rate in Group I during a maximum of 69 months was 67%, in Group II, in which residual stenoses were treated with stents, 100% during max. 18 months. Obviously stents help to improve the results after percutaneous recanalization of iliac artery occlusions significantly.

Adult↗
PubMed1991

Laser angioplasty: results of a prospective, multicenter study at 3-year follow-up.

A prospective multicenter trial was initiated to evaluate the efficacy and safety of laser angioplasty. Laser recanalization was performed in 338 patients with arteriosclerotic femoropopliteal artery occlusions (average length, 8.5 cm). Neodymium-yttrium-aluminum-garnet lasers were used in combination with sapphire probe catheters. The initial recanalization rate was 85%. Complications were observed in 14% of the patients. Emergency surgery was required in 1.5%. The cumulative long-term patency rate of the successfully recanalized arteries was 80%, 70%, 62%, and 57% at 6 months, 1 year, and 2 and 3 years, respectively. The patency rates were not affected by the length of the occlusion and the long-term medication (platelet inhibition vs anticoagulation), but patients with a normal runoff had significantly better patency rates than those with reduced runoff (63% vs 52%, P less than .01). The study has shown that laser-assisted angioplasty is safe and at least as effective as conventional angioplasty.

Adult↗
PubMed1991

Nd:YAG laser with sapphire tip combined with balloon angioplasty in peripheral arterial occlusions. Long-term results.

In 167 patients with complete occlusion (greater than 3 cm) of the femoropopliteal artery, percutaneous transluminal laser angioplasty (PTLA) was performed after an unsuccessful attempt at crossing with a guide wire and was immediately followed by balloon dilatation. An Nd-YAG laser and an optical fiber delivery system with a sapphire tip serving as a contact probe were used for PTLA. In 132 of 167 (79%) patients, the occluded segment was successfully reopened. Clinical symptoms improved in 126 of 167 (75%) patients. PTLA was unsuccessful in 35 patients, and in 15 of these, injury of the vessel wall occurred. In one patient, surgical drainage of a large hematoma became necessary. All patients in whom recanalization had been achieved were randomized to receive long-term treatment with either phenprocumarol or acetylsalicylic acid (ASA) plus dipyridamole to prevent rethrombosis. At 36 months of follow-up, the cumulative patency rate (CPR) was 63%. A complete reobstruction in 32 patients (24%) and a partial reobstruction in 15 patients (11%) were found angiographically. The CPR after 36 months was significantly lower (p less than 0.05) in patients younger than 60 years of age (54%) than in patients older than 60 (68%); it was also significantly lower (p less than 0.05) in patients with reduced peripheral runoff (55%) due to obstructed arteries of the lower leg than in patients with unaffected runoff (73%). The CPR was 65% in recanalized segments shorter than 7 cm and was 62% in recanalized segments longer than 7 cm.(ABSTRACT TRUNCATED AT 250 WORDS)

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