Search PubMed⌕ Search

Biomedical subjects

S Silber

Publications and source records attributed to S Silber.

At least 55 records · Page 3Linked to original sources
PubMed2000

[10 years of arterial closure devices: a critical analysis of their use after PTCA].

With worldwide over 1 million applications, vascular closure devices have been established as an essential tool of invasive cardiology. This overview compares today's four commercially available closure devices, VasoSeal (VS), Angio-Seal (AS), Perclose, Inc. (PC) and Duett (DU) for their usefulness after coronary interventions. The published data regarding deployment success rates for VS, AS, PC and DU are in the range of 88%, 91%, 90% and 98% up to 100%, respectively. Times to hemostasis were 5-13', 2-4', 11-19' and 4-14', accompanied by times to mobilization of 6-9 h, 6-8 h, 4-7 h and 2-6 h. Minor complications were described in 8%, 5.9%, 5.3% and 2.1%, major complications in 5.3%, 1.3%, 4% and 2.6%. Although none of the closure devices has been shown to reduce major local complications as compared to manual compression, all sealing devices have documented a significant reduction in time to hemostasis. The increased patient comfort is essentially related to the ability of sheath removal immediately after PTCA. Vascular closure devices reduce the burden of medical staff and decrease hospital costs by earlier discharge.

Angioplasty, Balloon, Coronary↗
PubMed2000

Pediatric advanced life support training of pediatricians in New Jersey: cause for concern?

OBJECTIVE: The Pediatric Advanced Life Support (PALS) course teaches the fundamental basics for pediatric emergency care, and it is recommended that all physicians, nurses, and paramedics who care for children complete training and refresher courses on a regular basis. The purpose of this study was to determine how many pediatricians in general practice participated in PALS courses in the first 3 years since its introduction in New Jersey. METHODS: A questionnaire was sent to all PALS training centers in New Jersey that administered the course from 1990 through 1993. The questionnaire was designed to determine the number of physicians trained; their specialty, and their practice setting. The questionnaire and follow-up telephone interviews focused on the perceptions of course coordinators as to why primary care pediatricians did or did not take PALS courses, and their recommendations for improving pediatrician participation. RESULTS: Two PALS training centers provided courses for only 1 year and did not maintain records of their students. A total of 3652 individuals completed training in the remaining 11 centers. Only 649 of these students were physicians. The largest groups of physicians who completed training were Emergency Medicine physicians (248) and Pediatric residents (175). Forty-two students were pediatricians in general office-based practice, which represents a crude rate of only 0.81% of New Jersey American Academy of Pediatrics (AAP) members. Training center coordinators offered several opinions for these findings. CONCLUSIONS: The majority of those students who participated in PALS training were not physicians. Pediatricians in general office practice accounted for a small percentage of those who could have participated. Further research should be conducted to determine attitudes toward PALS training and the barriers that exist to the office-based pediatrician participating in PALS training.

Child↗
PubMed2000

[Second and Third Annual Report of the German Society of Coronary Angiography and Interventions in Private Practice (BNK) concerning quality assurance in invasive cardiology].

Since 1995, the German Society for Cardiac Angiography and Interventions in Private Practice (BNK) has been intensely involved in quality assurance; since 1996, it has registered relevant data for diagnostic left heart catheterization (DIAG) and coronary interventions (PTCA). The following data are based on a total of 72,777 cardiac catheters, of which 54,513 were DIAG and 18,264 were PTCA (DIAG in 1996: 10,316; in 1997: 15,692 and in 1998: 28,505. PTCA in 1996: 2,597; in 1997: 5,600 and in 1998: 10,067). The mean patient age was 61.9 years for males and 65.3 years for females (31%). DIAG was performed on an out-patient basis in 60% of the cases. The proportion of self-referrals is circa one-third and has not increased over time. A s/p PTCA was present in 21% of the DIAG patients; those after coronary bypass surgery showed a steadily increasing trend towards a follow-up DIAG (8% of the patients). There was a distinctive decrease in the use of contrast medium from an average of 164 ml (1996) to 138 ml (1998). The symptoms leading to DIAG did not substantially change in the years from 1996 to 1998; the angiographic range of the coronary disease and the degree of an impaired myocardial function have remained virtually unchanged. The treatment recommendations appear to tend towards medical therapy with decreasing indications for PTCA (20%) and open heart surgery (16%). The mean duration of a PTCA procedure decreased from 57 +/- 8 (1996) to 44.6 +/- 25 (1998) minutes. The success rates remained unchanged for coronary stenoses as well as for recanalization of chronic total occlusions. PTCA complications: the incidence of abrupt coronary occlusions was 2% and of emergency bypass surgery 0.4%; mortality was 0.1%.

Aged↗
PubMed1999

A novel vascular sealing device for closure of percutaneous arterial access sites.

The purpose of this study was to investigate the safety and efficacy of a novel vascular sealing device that incorporates a unique low-profile balloon-positioning catheter and a procoagulant delivered after diagnostic cardiac catheterization and percutaneous transluminal coronary angioplasty (PTCA) procedures. Current management of the vascular access site after percutaneous interventions is associated with patient discomfort and complications. Based on previously reported successful results in canine models, we proceeded with this first human feasibility and safety study. Immediately after an invasive procedure, the sealing device was successfully deployed at the femoral arterial access site in 24 of 24 procedures (diagnostic 19, PTCA 5). All patients were followed up at 1 month with clinical assessment, ankle-brachial index measurement, and Doppler ultrasound. Successful hemostasis was achieved in all patients. The activated clotting time before sealing device deployment was 125.5 +/- 22.2 and 267.8 +/- 60.0 seconds for diagnostic and PTCA patients, respectively. The time to hemostasis was 2.5 +/- 0.9 minutes for diagnostic and 6.0 +/- 2.2 minutes for PTCA patients. No major complications were observed. Coagulation markers (fibrinogen, D-dimer, thrombin-antithrombin-3 complex, and prothrombin fragment 1 and 2) measured before and after sealing device deployment did not reveal excessive intravascular thrombin generation or other coagulopathy. This novel vascular sealing device successfully achieves safe and effective vascular access site hemostasis immediately after cardiac catheterization and PTCA. These promising first human results will need to be confirmed by a multicenter randomized trial.

Aged↗
PubMed1999

Final report of the European multi-center registry using the Duett vascular sealing device.

Duett, a novel vascular sealing device, was first clinically used in July 1997. A European multi-center registry was established to evaluate the safety and procedural success of the Duett sealing device in a broad range of patients undergoing diagnostic or interventional endovascular procedures. At 25 European sites 1587 patients were enrolled. All patients (> or = 18 years) must have given informed consent for the use of the sealing device after a diagnostic and/or interventional endovascular procedure performed via a femoral arterial approach. Standard length (< or = 10 cm) 5 to 9 F introducer sheaths had to be used. An ACT of < or = 400 s, and any approved GP IIb/IIIa platelet receptor antagonist was permitted. Successful deployment could be achieved in 96.2% (1526/1587 patients) with complete hemostasis within 2 to 5 minutes in over 95% of the patients. The complication-free rate was 96.4%. Arterial occlusions were rare (4 patients) and successfully treated with surgical repair in 1 and with thrombolysis in 3 patients. Pseudoaneurysms occurred in 34 patients, the majority (30/34) were successfully treated with ultrasound-guided compression or resolved spontaneously. The total rate of major complications was 2.6% (41/1587). The final results of the European registry demonstrate that the Duett sealing device can be used with a high procedural success following diagnostic and interventional endovascular procedures. The incidence of major complications is low and comparable to all other approved vascular closure devices and manual compression. CE-mark certification was approved at the end of 1998.

Adolescent↗
PubMed1999

An azoospermic man with a de novo point mutation in the Y-chromosomal gene USP9Y.

In humans, deletion of any one of three Y-chromosomal regions- AZFa, AZFb or AZFc-disrupts spermatogenesis, causing infertility in otherwise healthy men. Although candidate genes have been identified in all three regions, no case of spermatogenic failure has been traced to a point mutation in a Y-linked gene, or to a deletion of a single Y-linked gene. We sequenced the AZFa region of the Y chromosome and identified two functional genes previously described: USP9Y (also known as DFFRY) and DBY (refs 7,8). Screening of the two genes in 576 infertile and 96 fertile men revealed several sequence variants, most of which appear to be heritable and of little functional consequence. We found one de novo mutation in USP9Y: a 4-bp deletion in a splice-donor site, causing an exon to be skipped and protein truncation. This mutation was present in a man with nonobstructive azoospermia (that is, no sperm was detected in semen), but absent in his fertile brother, suggesting that the USP9Y mutation caused spermatogenic failure. We also identified a single-gene deletion associated with spermatogenic failure, again involving USP9Y, by re-analysing a published study.

Base Sequence↗
PubMed1999

No differences in outcome after intracytoplasmic sperm injection with fresh or with frozen-thawed epididymal spermatozoa.

This retrospective consecutive case series aimed at comparing the results of intracytoplasmic sperm injection (ICSI) with fresh and with frozen-thawed epididymal spermatozoa obtained after microsurgical epididymal sperm aspiration (MESA) in 162 couples. These couples were suffering from infertility because of congenital bilateral absence of the vas deferens (n = 109), failed microsurgical reversal for vasectomy or postinfectious epididymal obstruction (n = 44), irreparable epididymal obstruction (n = 4), ejaculatory duct obstruction (n = 2) or anejaculation (n = 3). Overall, 176 MESA procedures were performed in the husbands, followed by 275ICSI procedures with either fresh (n = 157) or frozen-thawed (n = 118) epididymal spermatozoa. No significant differences were observed in the parameters of spermatozoa used either freshly or frozen-thawed. In the fresh epididymal sperm group 59.4% of all the injected oocytes fertilized normally as compared to 56.2% of all injected oocytes in the frozen-thawed epididymal sperm group, and embryonic development was comparable between the two groups. A total of 245 transfers were performed: 145 after the use of fresh epididymal spermatozoa and 100 after the use of frozen-thawed spermatozoa. The overall pregnancy rate per ICSI cycle was significantly lower when frozen-thawed epididymal spermatozoa were used (26.3 versus 39.5%). However, no significant differences were found either in clinical and ongoing pregnancy rates or in implantation rates. There were no differences in pregnancy outcome. In patients suspected of having obstructive azoospermia with no work-up or an incomplete one, MESA is the preferred method for sperm recovery because a full scrotal exploration can be performed and, whenever indicated, a vasoepididymostomy may be performed concomitantly. Recovery of epididymal spermatozoa for cryopreservation during a diagnostic procedure is certainly a valid option in these patients since ICSI may be performed later or even in another centre using the frozen-thawed epididymal spermatozoa without jeopardizing the ICSI success rate.

Cryopreservation↗
PubMed1999

Men with infertility caused by AZFc deletion can produce sons by intracytoplasmic sperm injection, but are likely to transmit the deletion and infertility.

Deletion of the AZFc region of the Y chromosome is the most frequent molecularly defined cause of spermatogenic failure. We report three unrelated men in whom azoospermia or severe oligozoospermia was caused by de-novo AZFc deletions, and who produced sons by intracytoplasmic sperm injection (ICSI). We employed polymerase chain reaction (PCR) assays to examine the Y chromosomes of their four infant sons. All four sons were found to have inherited the Y chromosome deletions. Such sons are likely to be infertile as adults. This likelihood should be taken into account when counselling couples considering ICSI to circumvent infertility due to severe oligozoospermia or non-obstructive azoospermia.

Adult↗
PubMed1999

Usefulness of collagen plugging with VasoSeal after PTCA as compared to manual compression with identical sheath dwell times.

This study investigated the usefulness of collagen plugging with VasoSeal (Datascope Corporation, Montvale, New Jersey) in patients after PTCA compared to a control group having identical sheath dwell times and therefore comparable levels of anticoagulation. A total of 150 patients were enrolled in this prospective and randomized study. Sheaths were pulled at exactly 5 hours after arterial puncture. Time to hemostasis and local complications were determined. There were no statistical differences in baseline characteristics. The mean time to hemostasis in the collagen group was significantly shorter (3 +/- 3 minutes) than that of the control group (17.4 +/- 7 minutes). At 24 hours, 23% of the collagen group patients had a small, 1% a medium and 4% a large hematoma. In the control group, 32% had a small and 4% a medium-sized hematoma, but no patient a large hematoma. After collagen, one patient developed a pseudoaneurysm needing vascular surgery. In the control group, no major complications occurred. Compared to patients with manual compression at an identical sheath dwell time and an identical level of anticoagulation, there was a significant reduction in time to hemostasis but no statistical difference regarding local complications. Although the incidence of medium or large hematoma was low, the trend towards a decreased risk of smaller hematomas seemed to be counterbalanced by an increased risk of larger hematomas.

Aged↗
PubMed1998

Usefulness of collagen plugging with VasoSeal after PTCA as compared to manual compression with identical sheath dwell times.

This study investigated the usefulness of collagen plugging with VasoSeal in patients after PTCA compared to a control group having identical sheath dwell times and therefore comparable levels of anticoagulation. A total of 150 patients were enrolled in this prospective and randomized study. Sheaths were pulled at exactly 5 h after arterial puncture. Time to hemostasis and local complications were determined. There were no statistical differences in baseline characteristics. The mean time to hemostasis in the collagen group was significantly shorter (3 +/- 3 min) than that of the control group (17.4 +/- 7 min). At 24 h, 23% of the collagen group patients had a small, 1% a medium and 4% a large hematoma. In the control group, 32% had a small, 4% a medium sized, but no patient a large hematoma. After collagen, one patient developed a pseudoaneurysm needing vascular surgery. In the control group, no major complication occurred. Compared to patients with manual compression at an identical sheath dwell time and an identical level of anticoagulation, there was a significant reduction in time to hemostasis but no statistical difference regarding local complications. Although the incidence of medium or large hematoma was low, the trend towards a decreased risk of smaller hematomas seemed to be counterbalanced by an increased risk of larger hematomas.

Angioplasty, Balloon, Coronary↗
PubMed1998

[First annual report of practitioners of interventional cardiology in private practice in Germany. Results of procedures of left heart catheterization and coronary interventions in the year 1996].

The German Society for Cardiac Angiography and Interventions in Private Practice has started a registry of cardiac procedures since 1996 in order to establish a standard for performance. Although quality management for the cath lab makes sense and is also legally required, there is no generally recommended infrastructure for quality assurance existing in Germany at this time. Therefore, the German Society of Cardiologists in Private Practice (BNK) initiated a project in 1994 to develop a computer program for paperless documentation of diagnostic cardiac catheterizations and coronary interventions (PTCA) using a minimal data set. In 1996, 8 private associated groups participated in this project. The (anonymous) analysis of 10,316 diagnostic cardiac catheterizations and 2597 PTCA yielded the following results: In 95% of the patients, diagnostic cardiac catheterization was performed using the femoral and in 5% the brachial/radial approach. The mean volume of administered contrast medium was 164 +/- 138 ml/patient. The mean LV-EF was greater than 50% in 58.4% of the patients and between 30% and 50% in 10.1%. Coronary artery disease was diagnosed in 69.6% of the patients and valvular/congenital heart disease in 8.5%. In 18.4% of the patients undergoing diagnostic cardiac catheterizations no significant heart disease was identified. Mortality in the cath lab as well as the rate of cerebral insults was 0.05%. In 22.9% and 19% of the patients PTCA and cardiac surgery respectively was recommended. In patients undergoing PTCA, stable angina was present in 74.4% and unstable angina in 13.1%. Of the total number of PTCA procedures, 5.8% were performed in the setting of acute myocardial infarction. The PTCA lesion success rate was 96%, the mean diameter stenosis was 81% pre and 6% post-intervention. The mortality rate at 1 month post-PTCA was 0.4%, and myocardial infarction 1.0%. An acute occlusion occurred in 1.3% of the PTCA patients; 0.6% had to be transferred for emergency bypass surgery. None of the cath labs had on-site surgery. In comparison to other registries, our data show some similarities but also some different trends. Thus, our newly developed software proved to be reliable, fast and easy to use. Participating centers receive immediate feedback regarding their position within the whole group.

Angiocardiography↗
PubMed1998

[Intracoronary brachytherapy with strontium/yttrium-90. Initial experiences in Germany].

Restenosis after PTCA is still an unresolved problem and occurs in approximately 30% of our patients despite a stent implantation rate of up to 63%. Intracoronary brachytherapy has the potential to counteract the proliferative component of restenosis as well as to prevent shrinking of the coronary artery. Two years ago, we applied for the license to use the Novoste Beta-Cath system. This is the first report of its use in Germany. Attaining the license was complicated by the facts that this device did not yet have CE-certification (MPG section 17), that brachytherapy is not yet an approved method of treatment (StrSchV section 41), the report of the BfS and the approval by an accredited ethical committee. The application becomes even more complicated by the amount demanded by the LfU for insurance: 1 Million DM for each individual patient (AtDeckV section 15). The final local inspection needs to be performed by an expert from the LfAS (StrSchV section 76). Strontium-90 decays into Yttrium-90 with a half-life time of approximately 28 years. Yttrium-90, too, is a pure beta-emitter with a shorter half-life time of approximately 64 hours and a considerably higher electron energy of maximum 2.27 MeV. Yttrium-90 is the therapeutic agent. The radiation source of the Beta-Cath system consists of 12 single, separate cylinders (pellets, seeds) with a total length of 3 cm. The activity of the total train is approximately 1.3 to 1.5 GBq (35 to 40 mCi). For verification of the dose rate provided by the manufacturer, we performed a check using the GafChromic film. The test dose (exactly 2 mm from the center of the long axis of the activity train) was 150 Gy. We obtained the following results for the optical density: reference source: 0.29 +/- 0.01, source C: 0.318 +/- 0.013 and source D: 0.317 +/- 0.028. For a dose rate of e.g. 0.083 Gy/s, the radiation times are 169 s for a dose of 14 Gy (vessel diameter 2.7 to 3.35 mm) or 217 s for 18 Gy (vessel diameter 3.36 to 4.0 mm), respectively. In our cath lab, the following dose rates were measured: at the lead container: 20 microSv/h, surface of the transfer device: 400 microSv/h, surface of the phantom: 20 microSv/h and surface of the bail out box: 100 microSv/h. Because moving the source train to the tip of the catheter takes only approximately 1 s, the exposure to other tissues or organs is negligible. However, inappropriate handling of the device could cause significant radiation of other organs. Therefore, the importance of intensive training cannot be overemphasized. The results of the currently ongoing multicenter trials (Beta-Cath system trial in the USA and the BRIE trial in Europe) are being anxiously awaited and will have a decisive impact on the medical acceptance of intracoronary radiation for prophylaxis and/or therapy of restenosis.

Angioplasty, Balloon, Coronary↗
PubMed1998

[Accidental occlusion of the common femoral artery after Angio-Seal-application].

Removal of the arterial sheath immediately after PTCA is desirable for patients, reduces the medical staff's workload, and may decrease hospital costs due to a shortened length of stay. Although the safety and efficacy of the hemostatic systems used especially for the above purpose have been sufficiently documented, inadvertent intraluminal vascular occlusion is theoretically possible. While partial or complete arterial occlusion in conjunction with the VasoSeal collagen prototype device has been previously reported, similar complications occurring with the Angio-Seal device were not published. In this report, we describe a 54-year old female patient (height: 150 cm, weight: 42.5 kg) who was transferred for PTCA following an acute anterior wall myocardial infarction. Immediately after PTCA, the Angio-Seal device was deployed utilizing standard technique. No difficulties were encountered during device deployment, however, immediately following device placement active arterial bleeding occurred. Due to the inadequacy of hemostasis, heparin was reversed with protamine to avoid further hemorrhagic complications. Following this, the desired hemostasis quickly occurred, but the patient soon complained about symptoms suggestive of an acute occlusion of the right femoral artery. Unsatisfactory attempts at lysis resulted in the patient being transferred to vascular surgery. The complete Angio-Seal system (anchor including collagen) was located intravascularly, and removed during surgery. This case report demonstrates that even an experienced examiner can inadvertently deploy the Angio-Seal completely intraarterially. In addition to the known contraindication, "peripheral arterial occlusive disease", we recommend that the Angio-Seal device not be utilized in patients of small physical size.

Angioplasty, Balloon, Coronary↗
PubMed1998

Hemostasis success rates and local complications with collagen after femoral access for cardiac catheterization: analysis of 6007 published patients.

Since the first clinical studies regarding sealing of arterial puncture sites with collagen with the use of the vascular hemostatic device (VHD) and the hemostatic puncture closing device (HPCD) in the early 1990s were performed, no analysis summarizing the published patients has been reported. Therefore we performed a Medline search of data as far back as 1990 and included abstracts presented at the major scientific meetings in the United States (American Heart Association, American College of Cardiology), Europe (European Society of Cardiology), and Germany (German Society of Cardiology). A total of 6007 patients were found to have been enrolled in studies with VHD (4448 patients) or with HPCD (1559 patients). Parameters analyzed in this review were hemostasis success rates and local complications. To assess the impact of the sealing devices on local complications, studies without control groups were excluded. The hemostasis success rates immediately after deployment seemed to be higher for HPCD, but at 2' to 5' after sheath removal, they were in the same range for VHD and HPCD. In controlled studies minor local complications occurred at a rate of 7.6% in the VHD group and in 6.7% of the HPCD group. Because the control group in the HPCD studies showed a considerably higher rate of minor complications than the VHD group (11.7% vs 5.7%), the reduction in minor complications was statistically significant for HPCD, whereas VHD did not reduce minor local complications. Major local complications were reported in 3.8% of the VHD group but in only 1.8% of the HPCD group. The increase of major local complications was statistically significant with VHD (control, 1.7%) but not with HPCD (control, 1.4%). Our analysis shows that some differences between collagen devices may exist, but neither device has been proven to reduce major local complications.

Cardiac Catheterization↗
PubMed1998

Enzymatic digestion of testicular tissue may rescue the intracytoplasmic sperm injection cycle in some patients with non-obstructive azoospermia.

Recovery of testicular spermatozoa from azoospermic patients with testicular failure, followed by intracytoplasmic sperm injection (ICSI) is a recent advance in the treatment of male infertility. In most cases, free spermatozoa are recovered from testicular tissue after mechanical mincing of multiple biopsies. Testicular sperm retrieval, however, remains unsuccessful in 30-50% of male patients suffering from Sertoli cell-only syndrome and maturation arrest. In this study, a strategy was developed in order to maximize the chance of sperm retrieval in difficult cases of testicular failure. The ultimate step was the use of enzymatic procedures (collagenase type IV) to dissociate the testicular tissue completely. Testicular tissue of 41 patients for whom no spermatozoa were found after mechanical mincing of the testicular tissue was investigated. In 14 out of the 41 cases (34%), enough spermatozoa for ICSI were found after fine mincing of multiple biopsies and several hours' search in the cell suspension treated with the erythrocyte-lysing buffer (ELB). In 27 out of the 41 patients, no spermatozoa were found even after the use of ELB. In seven out of these 27 failures (26%), spermatozoa for ICSI were retrieved after enzymatic dissociation of the residual minced tissue pieces, thus making ICSI possible despite failure to find spermatozoa with conventional mincing. From this study, we may conclude that enzymatic digestion of testicular tissue is easy to perform, is not time-consuming and constitutes a successful method in reducing the sperm recovery failures in patients with non-obstructive azoospermia.

Adult↗
PubMed1997

Impact of various compression rates on interpretation of digital coronary angiograms.

According to the ACC/ACR/NEMA/ESC-guidelines, digital techniques should be replaced by cinefilm for coronary angiography. The ad hoc group of experts recently chose CD-R (CD recordable) as transport media and the JPEG standard for image compression. To avoid a possible loss of image quality, the guidelines allow a maximal data compression of only 2:1. This, however, leads to a considerable limitation: coronary angiograms cannot be viewed in real-time directly from CD. Since the possible influence of higher compression rates on image quality of coronary angiograms had not been investigated in a controlled study, we evaluated 8 various compression rates (ranging from 5:1 to 43:1) according to a prospective, randomized and blinded protocol. Four independent observers assessed 1440 angiograms using a semiquantitative score. We found that angiograms with a compression rate of 5:1 and 6:1 did not lead to a clinically relevant deterioration of image quality, whereas 11:1 was still acceptable, but 43:1 becomes unacceptable. Since no clinically relevant loss of information at a compression rate of 6:1 was experienced in our study, a modification of the ACC/ACJ/NEMA/ESC-guidelines allowing higher compression rates should be considered.

Angiography, Digital Subtraction↗