Biomedical subjects

Werner Weber

Publications and source records attributed to Werner Weber.

11 recordsLinked to original sources

PubMed2006

Repeated endovascular coil occlusion in 350 of 2759 intracranial aneurysms: safety and effectiveness aspects.

OBJECTIVE: Evaluation of the safety and effectiveness of endovascular retreatment of intracranial aneurysms with detachable coils. METHODS: Retrospective analysis of clinical outcome as well as angiographic studies both before and after coil retreatment. The indication for retreatment was based on either inadequate occlusion after previous treatment or recurrent perfusion of the aneurysm. RESULTS: A total of 2759 intracranial aneurysms in 2360 patients were treated by endovascular coil occlusion. Of those, 350 (12.3%) aneurysms underwent a second treatment, and 94 (3.4%) aneurysms underwent three or more treatment sessions. The second treatment sessions were performed an average of 27.2 months after the previous procedure. The third and following treatment sessions were conducted an average of 25.3 months after the previous procedure. Initial treatment resulted in 100% occlusion in 63.7% of aneurysms. One hundred percent occlusion was achieved in only 46.9% of the second and 35.2% of the third and following sessions. Stent-assisted coil treatment was used in 5.6% of initial, 28.0% of second, and 20.7% of third and following sessions. Initial treatment sessions were uneventful in 83.2% of cases, second sessions in 86.9% of cases, and third and following sessions in 87.6% of cases. The morbidity-mortality rate for 495 retreatment sessions was 2.2% (n = 11). CONCLUSION: The natural course of aneurysm remnants or recurrent aneurysm perfusion after coil treatment is not completely understood. The low risk of bleeding from partially filled aneurysms must be balanced against the procedure-related risks of retreatment. Great caution is recommended for the treatment of asymptomatic recurrent aneurysms.

Embolization, Therapeutic↗

PubMed2006

Elective treatment of saccular and broad-necked intracranial aneurysms using a closed-cell nitinol stent (Leo).

OBJECTIVE: Endovascular coil embolization of saccular intracranial aneurysms is safe and effective, but long-term results are dissatisfying. Reconstructive treatments using stents improve occlusion rate and protect parent vessels. We present data on our experience with a new self-expanding stent manufactured with braided nitinol wires. METHODS: Twenty-five saccular, complex, and broad-necked intracranial aneurysms in 21 patients were treated electively. They were located at the internal carotid artery (10), basilar trunk (5), cavernous carotid artery (4), basilar tip (2), anterior cerebral artery (2), anterior communicating artery (1), and middle cerebral artery (1). Eleven aneurysms exhibited recanalization after primary endovascular treatment without stent. RESULTS: Stent deployment was successful in 24 lesions, and additional coil embolization was performed in 23. No permanent neurological deficits were encountered consequent to endovascular procedure. Complete or partial occlusion immediately after stent deployment was achieved in 19 aneurysms, whereas no immediate coil embolization was chosen in 6 cases. There were two thromboembolic events related to the deployment of the Leo stent, one failure of stent deployment, difficulties in stent positioning in three cases, and one asymptomatic parent artery occlusion after 7 months. Follow-up (available in 18 patients and 21 aneurysms and obtained at 3-12 mo; average, 5 mo) revealed patent stents in the remaining cases. Angiographic recurrences arose in three lesions, which were retreated without complications. CONCLUSION: Primary and recurrence treatment of saccular and broad-necked intracranial aneurysms using the Leo stent is feasible and effective. No permanent neurological deficits were associated with stent placement. Short-term follow-up identified intact parent arteries and stable occlusion rates in the majority of cases.

Adult↗

PubMed2005

Angiographic and clinical results in 316 coil-treated basilar artery bifurcation aneurysms.

OBJECT: The aim of this study was to analyze the effect of the endovascular treatment of basilar artery (BA) bifurcation aneurysms and to compare the results with those published by other neuroendovascular teams. METHODS: The authors performed a retrospective analysis of 316 aneurysms of the BA bifurcation that had been treated using endovascular coil occlusion between November 6, 1992, and February 12, 2005. After the initial embolization procedure, a 90 to 100% occlusion rate was achieved in 86% of the aneurysms. No complication was evident in 80% of the lesions, although periprocedural aneurysm rupture (3.2%) and thromboembolic events (12.3%) were the most frequent complications. Clinical outcome according to the Glasgow Outcome Scale (GOS) was a score of 5 or 4 in 77%, 3 in 11%, 2 in 5%, and 1 in 7% of patients. Initial follow-up angiography studies were obtained in 56% of patients at a mean of 19 months posttreatment and demonstrated a 90 to 100% occlusion rate in 70%. No recurrence was seen on 65% of the aneurysms. Coil compaction was evident on 24% of the follow-up angiograms. A second treatment was performed on 48 aneurysms (15%) a mean of 27 months after the first therapeutic session and resulted in 90 to 100% occlusion in 83% of the lesions. Complications were encountered in 19% of the aneurysms. Rupture did not occur during any of the procedures. Clinical outcome was rated as GOS Score 5 or 4 in 83% of the patients and Grade 3 in 17%. During a cumulative clinical follow up of 821 years in 237 patients, 182 patients (81%) were independent (GOS Score 5 or 4), 33 (14%) were dependent (GOS Score 3), eight (3%) were in a vegetative state, and two (1%) had died. Clinical outcome was significantly worse after previous aneurysm rupture and following procedural complications. CONCLUSIONS: These results are within the range of published data for coil treatment of BA tip aneurysms and confirm both the safety and efficacy of this endovascular treatment method.

Aneurysm, Ruptured↗

PubMed2005

Treatment and follow-up of 22 unruptured wide-necked intracranial aneurysms of the internal carotid artery with Onyx HD 500.

BACKGROUND AND PURPOSE: The purpose of this study was to demonstrate endovascular treatment of wide-necked aneurysms of the internal carotid artery with the liquid embolic agent Onyx HD 500. METHODS: Twenty-two wide-necked, large or giant aneurysms of the internal carotid artery (ICA) were treated in 22 patients with Onyx HD 500 (15 ophthalmic, 1 clinoid, and 6 cavernous aneurysms). Sixteen patients were asymptomatic, and mass effect of the aneuryms caused cranial nerve palsy in 6. Seven aneurysms showed regrowth after prior endovascular coiling. RESULTS: Postinterventional angiography demonstrated total occlusion in 18 aneurysms, and a small remnant was left in 4. Clinical and angiographic follow-up data are available in 19 patients (average follow-up, 13 months; range, 5-36 months). Total occlusion was demonstrated in 17 aneurysms (91%), and a partial recanalization was seen in 2. There were 2 ICA occlusions and 1 ICA stenosis. Clinical follow-up demonstrated a transient ischemic attack in 1 patient; 2 with cranial nerve palsy were unchanged, and 2 showed improved symptoms compared with the findings before treatment. The remaining 14 patients were clinically asymptomatic. There was no permanent severe morbidity and no mortality at follow-up. CONCLUSION: The endovascular treatment of wide-necked, large or giant ICA aneurysms with Onyx HD 500 is a treatment option in these selected cases. The benefit is a primary high and stable occlusion rate and good clinical outcome. ICA occlusion caused by Onyx migration in the parent artery is a typical problem, with a benign clinical course in this series.

Adult↗

PubMed2005

Integrated microelectronics for smart textiles.

The combination of textile fabrics with microelectronics will lead to completely new applications, thus achieving elements of ambient intelligence. The integration of sensor or actuator networks, using fabrics with conductive fibres as a textile motherboard enable the fabrication of large active areas. In this paper we describe an integration technology for the fabrication of a "smart textile" based on a wired peer-to-peer network of microcontrollers with integrated sensors or actuators. A self-organizing and fault-tolerant architecture is accomplished which detects the physical shape of the network. Routing paths are formed for data transmission, automatically circumventing defective or missing areas. The network architecture allows the smart textiles to be produced by reel-to-reel processes, cut into arbitrary shapes subsequently and implemented in systems at low installation costs. The possible applications are manifold, ranging from alarm systems to intelligent guidance systems, passenger recognition in car seats, air conditioning control in interior lining and smart wallpaper with software-defined light switches.

Algorithms↗

PubMed2004

Stent-angioplasty of intracranial vertebral and basilar artery stenoses in symptomatic patients.

BACKGROUND: To present our two-center treatment results with stent angioplasty of intracranial vertebrobasilar stenoses in symptomatic patients. MATERIAL AND METHODS: Between 2001 and 2003, 21 patients with 22 stenoses, refractory to medical therapy, who underwent elective stenting of intracranial vertebrobasilar stenoses were retrospectively analyzed. All patients had ischemic events clinically referable to the stenoses. Only high-grade stenoses of at least 80% were treated. Clinical evaluation was done based on the modified ranking scale (MRS). RESULTS: In all cases, the stent deployment turned out to be technically successful and control angiography demonstrated the elimination of the high-grade stenoses. A minor residual stenoses was still detectable in six cases. According to the MRS, clinical outcome improved in the case of four patients, seemed unchanged in 14 and worsened in three. The clinical morbidity rate amounted to 14%. Clinical follow-up was available for 13 patients after 9 months with no recurrent symptoms and angiographic follow-up was available after 10 months. Re-stenoses occurred in two cases without clinical symptoms. Retreatment was not done. CONCLUSION: According to our data, stent angioplasty for symptomatic intracranial vertebrobasilar stenoses can be a treatment alternative in case of recurrent symptoms despite medical therapy; particularly, for stenoses of type Mori A or B.

Aged↗

PubMed2004

Pharmacokinetics of intravenous, single-dose tiotropium in subjects with different degrees of renal impairment.

Tiotropium, a new potent anticholinergic bronchodilator, is excreted mainly by the kidney. To investigate the pharmacokinetics of tiotropium in renal impairment, the authors evaluated the pharmacokinetics and safety after administration of a single dose of intravenous tiotropium 4.8 microg, given as an infusion over 15 minutes in subjects with normal renal function and a wide range of renal impairment based on measured creatinine clearance (normal: > 80 mL/min, n = 6; mild impairment: > 50-80 mL/min, n = 5; moderate impairment: 30-50 mL/min, n = 7; severe impairment: < 30 mL/min, n =6). As expected for a drug excreted predominantly in unchanged form by the kidneys, tiotropium plasma concentrations increased as renal impairment worsened, with mean values of 55.5 (16.2 percent geometric coefficient of variation [%gCV]), 77.1 (20.1 %gCV), 101 (29.8 %gCV), and 108 (27.3 %gCV) pgh/mL for AUC(0-4h) in the normal renal function and the mild, moderate, and severe renal impairment groups, respectively. The percentage of tiotropium dose excreted unchanged in the urine decreased from 60.1% of dose (17.7 %gCV) to 59.3% (14.4 %gCV), 39.9% (34.5 %gCV), and 37.4% (10.2 %gCV) in the normal renal function and the mild, moderate, and severe renal impairment groups, respectively. Plasma protein binding of tiotropium did not significantly change in the renal-impaired subjects. Two subjects with normal renal function experienced headache 10 hours after the infusion, which was mild and transient. No adverse events occurred in subjects with renal impairment. There were no clinically relevant changes in blood pressure, pulse rate, 12-lead ECG, physical examination, hematology, or clinical chemistry, compared with baseline values, in any subject after intravenous administration of tiotropium. Tiotropium should only be used in patients with moderate to severe renal insufficiency if the potential benefit outweighs the potential risks.

Adult↗

PubMed2004

Endovascular coil occlusion of 1811 intracranial aneurysms: early angiographic and clinical results.

OBJECTIVE: We sought to evaluate the early angiographic and clinical outcomes of the first session of endovascular coil occlusion of a large number of patients with intracranial aneurysms treated by five neurointerventionalists during a decade at a single center. METHODS: We performed retrospective analyses of pre- and postprocedural angiographic studies and early clinical outcomes. Enrolled patients underwent endovascular treatment of intracranial aneurysms with detachable coils. RESULTS: A total of 1811 aneurysms in 1579 patients were treated with coil occlusion. Of these, 90 to 100% occlusion of 86.5% of the aneurysms was achieved. In 82.3% of the procedures, no complications occurred. The clinical outcome profile at primary discharge according to the Glasgow Outcome Scale was as follows: Grade V, 74.6%; Grade IV, 6.7%; Grade III, 11.1%; Grade II, 3.1%; and Grade I, 4.5%. In patients with large aneurysms with wide necks, a lower occlusion rate and an increased complication rate were encountered. The use of three-dimensional and fibered coils resulted in higher occlusion rates. Balloon remodeling and stent deployment increased the complication rate. Previous aneurysm rupture, procedural complications, and vasospasm correlated with poor outcome. Of the patients in poor grade after aneurysm rupture, 42% recovered to Glasgow Outcome Scale Grade IV or V, as opposed to 90% of patients who were treated for unruptured aneurysms. The ischemic complication rate was 9%, and the hemorrhagic complication rate was 3%. The early procedural morbidity rate was 5.3%, and the procedural mortality rate was 1.5%. The management mortality rate was 4.4%. CONCLUSION: These data confirm the safety and efficacy of endovascular coil occlusion for patients with intracranial aneurysms.

Adolescent↗

PubMed2004

Treatment of extracranial and intracranial aneurysms and arteriovenous fistulae using stent grafts.

OBJECTIVE: Treatment of 11 patients with aneurysms or arteriovenous fistulae of the craniocervical arteries with stent grafts. METHODS: Peripheral stent grafts were deployed in two extracranial internal carotid arteries. Coronary stent grafts were used to treat two giant aneurysms, five direct carotid-cavernous fistulae, one vertebrojugular fistula, and two dissecting aneurysms of the vertebral artery (V2 and V4). RESULTS: Stent grafts were used successfully in two extracranial internal carotid and two extracranial vertebral arteries, one dissecting aneurysm of the intracranial vertebral artery, one giant aneurysm and one pseudoaneurysm of the cavernous internal carotid artery, and five direct carotid-cavernous sinus fistulae. Angiographic follow-up examinations (available in nine patients; obtained at 3 mo to 5 yr; average, 24 mo) revealed normal vessel caliber, and the stent grafts in all 9 of 11 initial patients were patent. There was a recurrent saccular aneurysm adjacent to the stent graft in the patient with the intracranial vertebral artery aneurysm. The following five complications were encountered: transient hemiparesis (n = 2), increased hemiparesis, postprocedural management-related fatality, and ICA dissection. In six patients, stent graft deployment was accomplished without any technical or clinical complication. There were no permanent neurological deficits consequent to stent graft placement. CONCLUSION: Stent grafts are a useful tool for the endovascular treatment of head and neck aneurysms and direct arteriovenous fistulae in selected patients. The major disadvantage of the currently available stent grafts is their lack of mechanical flexibility. Maneuvering stent grafts in the intracranial arteries carries the risk of iatrogenic vessel dissection and may require supportive measures and protection of the target site by conventional stents.

Adult↗

PubMed2004

Doppler sonographic evaluation of shunts in patients with dural arteriovenous fistulas.

BACKGROUND AND PURPOSE: Doppler sonography has been used to assess global cerebral circulation time (CCT) in healthy volunteers and a small number of patients with cerebral arteriovenous malformations. We evaluated the effect of arteriovenous shunts on global CCT in patients with dural arteriovenous fistulas (DAVFs) by using this Doppler echo contrast-bolus tracking test. METHODS: We measured CCT as the time delay in a contrast bolus to the internal carotid artery (ICA) and internal jugular vein (IJV) in 13 patients with DAVF and 30 age-matched control subjects. Mean CCT and mean arterial and venous rise times (Delta t = 80% of total signal-intensity increase) were compared. Posttreatment follow-up measurements were performed in five patients. RESULTS: Mean CCT and venous Delta t were significantly different between patients and controls (CCT, 1.1 +/- 0.9 vs 6.9 +/- 1.2 seconds, P <.0001; venous Delta t, 5.2 +/- 2.0 vs 7.0 +/- 2.6 seconds, P =.024), but arterial Delta t values were not (4.4 +/- 1.8 vs 4.7 +/- 2.0 seconds). Posttreatment follow-up of two occluded fistulas showed CCT normalization. One near-occlusion showed a two-step increase in signal intensity, and incomplete occlusion in two patients left the CCT unchanged. One patient with an extracranial, highly vascularized glomus tumor draining into the IJV had a CCT of 1.8 seconds. CONCLUSION: In DAVF patients, sonographic CCT is significantly shortened. Our test is highly sensitive for arteriovenous shunts but not specific for DAVF alone. Follow-up measurements in DAVF patients are well correlated with results of angiographic treatment. CCT assessment might become an additional tool for evaluating these patients and monitoring their treatment.

Adult↗

PubMed1992

Patient controlled analgesia for extracorporeal shock wave lithotripsy of gallstones.

Sixty patients undergoing shock wave lithotripsy of gallbladder stones (ESWL) were randomly assigned to receive alfentanil either by infusion controlled by the attending anesthesiologist (standard treatment group, n = 31) or by analgesia controlled by the patient (PCA group, n = 29). Patients using PCA were allowed to self-administer 0.25 mg of alfentanil i.v. every minute as required. Data collected during treatment included the total dose of drug required, transcutaneous pCO2 values, verbal pain and sedation scores, visual analogue scale (VAS) patient satisfaction scores, and the incidence of nausea or vomiting. PCA patients used less alfentanil than the standard treatment group (PCA group: 12.8 micrograms/kg; standard treatment group: 44.3 micrograms/kg; mean values, P = 0.0001), tolerated significantly higher pain intensities and self-administered the narcotic only to moderate levels of pain but not to pronounced analgesia. Standard treatment patients reported lower levels of pain, were more sedated (P less than 0.05) and showed significantly higher transcutaneous pCO2 values. There was a trend towards a lower incidence of nausea or vomiting in PCA patients without reaching statistical significance. No significant difference with regard to patient satisfaction with pain relief could be demonstrated. Self-administered alfentanil during ESWL of gallbladder stones provided adequate analgesia with minimal side effects and high patient satisfaction. ESWL may represent a new and useful indication for PCA.

Adult↗