A randomized comparison of a durable polymer Everolimus-eluting stent with a bare metal coronary stent: The SPIRIT first trial

BACKGROUND

Everolimus is a sirolimus analogue with similar efficacy in animal models, and has been previously successfully tested in humans using an erodable polymer.

METHODS

This first-in-man single blind multi-centre randomized controlled trial assessed the safety and efficacy of everolimus eluting from a durable polymer on a cobalt chromium stent in patients with de novo native coronary artery lesions. Sixty patients were allocated to stent implantation with an everolimus-eluting stent (n=28) or an identical bare stent (n=32). Patients had either stable, unstable angina or silent ischaemia. Suitable lesions treated were single de novo native coronary lesions with 50-99% stenosis and could be covered by a 18 mm stent. The primary endpoint was in-stent late loss at 180 days, analysed on a per treatment basis. The major secondary endpoint was percent in-stent volume obstruction (%VO) as measured by intravascular ultrasound (IVUS) at 180 days. The clinical secondary endpoint was major adverse cardiac events (MACE) at 180 days.

RESULTS

At 6 months, (matched pairs angiographic analysis), the in-stent late loss, percentage diameter stenosis and percentage of patients with binary restenosis were 0.10 mm, 16% and 0% respectively, in the everolimus arm (n=23), as compared with 0.87 mm, 39% and 25.9%, respectively in the bare stent arm (n=27, p<0.001 for late loss and diameter stenosis, p = 0.01 for restenosis). Significantly less neointimal hyperplasia was observed in the everolimus group compared to the bare stent group (10 +/- 13 mm3 vs 38 +/- 19 mm3, p<0.001) and similarly, less volume obstruction (8.0 +/- 10.4% versus 28.1 +/- 14.0%, p<0.001). A major adverse cardiac event occurred in 2 patients in the everolimus arm versus 6 in the bare stent arm.

CONCLUSION

Everolimus eluted from a durable polymer on a cobalt chromium stent effectively suppresses neointimal growth at 6 months compared to an identical bare stent.

Computertomographische Untersuchung von Muskelvolumen, -querschnitt und -dichte bei Dysgnathiepatienten

PURPOSE

The individual jaw position is determined by the masticatory muscle among other factors. Before surgical treatment of malocclusions, thorough evaluation of the muscles is required to estimate the relapse risk.

MATERIALS AND METHODS

By means of computer tomography, lateral radiographs of the skull and denture models, the relationships between morphological parameters of the masticatory muscles and the jaw bone were analyzed. Furthermore, possible causes for the extent of the malocclusion are described.

RESULTS

A patient group with deep overbite was found to have significantly higher muscle densities (measured in Hounsfield units [HU]) in the medial pterygoideus muscle (59.89 +/- 3.91 HU to 48.94 +/- 4.14 HU, p < 0.01), masseter muscle, and genioglossus muscle (p < 0.05) in comparison to open bite patients. Significant differences of the muscle cross-section were measured in the masseter muscle between patients with retroclined maxillary incisors and with an open bite (5.4 +/- 0.7 cm (2) to 3.8 +/- 0.4 cm (2), p < 0.05).

CONCLUSION

The results show a correlation between different jaw positions and masticatory muscles. They also suggest that the function of each muscle may be different. Additional examinations of the muscle structures are required for verification of the influence of the masticatory muscles on facial morphology.

Endovascular Interventions in Iliac and Infrainguinal Occlusive Artery Disease

Percutaneous endovascular procedures are increasingly applied to treat symptomatic peripheral occlusive artery disease. While the primary technical success and recanalization rates in iliac and infrainguinal interventions are high, differences in the long-term patency rates exist with respect to the anatomic localization, separating the iliac, femoropopliteal, and infrapopliteal arterial regions. In iliac arteries, even complex lesions can be recanalized with good long-term patency rates, especially when using self-expanding nitinol stents. In the infrainguinal arteries the method of choice is still under debate (e.g., balloon angioplasty vs stent implantation). A high restenosis rate represents one of the major limitations in femoropopliteal and infrapopliteal interventions. Therefore, additional methods and treatment strategies for peripheral interventions with the potential for future applications are under investigation and will be discussed such as drug-eluting stents, brachytherapy, subintimal angioplasty, laser angioplasty, atherectomy/thrombectomy, cutting balloon, polytetrafluoroethylene (PTFE)-covered stent grafts, biodegradable stents, and cryoplasty. The increasing amount of data on successful peripheral interventions supports the necessity to adapt and reevaluate the current consensus guidelines that were put together in 2000.

Relationship between Size of Myocardial Infarctions Assessed by Delayed Contrast-Enhanced MRI after Primary PCI, Biochemical Markers, and Time to Intervention

BACKGROUND

The quantitative assessment of myocardial infarctions using delayed contrast-enhanced magnetic resonance imaging (MRI) has recently been validated using postmortem histopathological animal studies. In a prospective study, we investigated the correlation between infarct size as assessed by delayed contrast-enhanced MRI, elevation of creatine kinase (CK), and c-reactive protein (CRP) as well as the time from onset of symptoms to intervention.

METHODS

Four to 10 days after immediate PCI in 45 acute ST-segment elevation myocardial infarction (STEMI) patients (<24 hour) with stenting of the infarct-related artery and treatment with abciximab, we performed gadolinium contrast-enhanced three-dimensional inversion recovery gradient-echo MR sequences with complete coverage of the LV-myocardium in short-axis slices. The mass of infarcted tissue based on the volume of hyperenhanced myocardium was calculated and linear regression analysis was performed to assess the correlation between absolute size of infarctions (g) as well as relative size (LV%) with peak values of CK, CRP, and the time to PCI.

RESULTS

There was a significant correlation between absolute size of infarctions (g) and peak CK values (r = 0.72; P < 0.001) as well as the relative size (LV%) and peak CK (r = 0.77; P < 0.001). No correlations were found between absolute size (r = 0.33) as well as relative size (r = 0.27) of infarctions and peak CRP. There was also no correlation between absolute (r = 0.29) as well as relative size of infarctions (r = 0.27) and the time from onset of symptoms to PCI.

CONCLUSIONS

In patients with acute STEMI (<24 hour) undergoing immediate PCI with stenting and treatment with abciximab, peak CK values correlated well with infarct size as assessed by delayed contrast-enhanced MRI. There were no correlations between infarct size and peak CRP as well as the time to intervention.

Clinical Experiences Using Everolimus-Eluting Stents in Patients with Coronary Artery Disease

Despite the growing use of drug-eluting stents, restenosis remains to occur especially in high risk subgroups like patients with diffuse in-stent restenosis. This observation is supporting the search for new and potentially even more effective drug eluting stent systems. Everolimus has been used in conjunction with a new bioabsorbable polymer and gave promising results in initial clinical studies. In FUTURE I, a single-center, single-blinded randomized safety and feasibility study enrolling 15 patients with bare metal stents and 27 patients with everolimus-coated stents, 30-day MACE rate was 0% in both groups. In-stent late loss at six months was 0.83 mm in the control group and 0.10 mm in the everolimus group (p < 0.0001). In FUTURE II, a randomized multi-center study, a total of 64 patients were enrolled confirming safety and feasibility. After 6 months late loss was 0.85 mm in the control group and 0.12 mm in the everolimus group (p < 0.001).

Influence of Doxycycline on Clinical and Angiographic Outcome Following Percutaneous Coronary Intervention

BACKGROUND

Infection with Chlamydia pneumoniae may be involved in atherosclerosis. Neointima proliferation after percutaneous coronary intervention (PCI) could be aggravated by proinflammatory action of chronic vascular chlamydial infection. We investigated the influence of doxycycline therapy on restenosis rate and adverse clinical event rates after PCI.

METHODS

We followed 1,019 consecutive patients in a single center nonrandomized observational study. During a 3-month period, all patients having PCI (n = 541; treatment group) received oral doxycycline 100 mg/day for 50 days starting from the day of the procedure. A control group (n = 478) consisted of consecutive post-PCI patients recruited from immediately preceding (n = 250) and ensuing periods. Event rates were gained by questionnaires after 259 +/- 57 days. Restenosis rate was derived from the routine angiographic restudies after 172 +/- 15 days.

RESULTS

No significant differences between treatment and control group were found in adverse clinical event rates (myocardial infarction: 0.7% vs 1.3%; repeat-PCI: 24.0% vs 20.9%; coronary bypass grafting: 5% vs 3.9%; overall death after 6 months: 3.5% vs 2.1%) and overall restenosis rate (21.6% vs 23.4%). A subgroup analysis of nondiabetic male smokers revealed a lower restenosis rate in the treatment group (10.9% vs 30.9%; P = 0.0195).

CONCLUSION

Doxycycline therapy for 50 days following PCI does not appear to have a substantial influence on the clinical and angiographic outcome in unselected patients. The observed reduction in restenosis rate among nondiabetic male smokers defines a new hypothesis that should stimulate further investigations.

Method for modelling cerebral blood vessels and their bifurcations using circular, homogeneous, generalised cylinders

A method for automatic modelling of blood vessels and their bifurcations from 3D scans of the brain is presented. The method is a three-step procedure. First, a skeleton of the cerebral blood vessels is developed, and then the surfaces of the blood vessels are located using an active contour approach. The active contour approach uses circular homogeneous generalised cylinders (CHGCs) to model the thin, elongated blood vessels. Finally, a novel method for modelling the surfaces of the bifurcations in a vessel tree is presented. The method was tested on simulated data: a computed tomography angiography (CTA) and four magnetic resonance angiography (MRA) volumes. Furthermore, the method was tested on ten magnetic resonance images (MRIs) to demonstrate its robustness. The test on the simulated data indicated that the approach for the surface modelling of vessels had a mean radius error of less than 0.1 mm and a mean localisation error of 0.1 mm. Surface models evaluated by an expert in vascular neurosurgery were found to have a smooth appearance and generally agreed with the image data. The test on the MRI scans indicated that the method performed well in noisy environments.

Long-term outcome after implantation of bare metal stents for the treatment of coronary artery disease: rationale for the clinical use of antiproliferative stent coatings

BACKGROUND

The widespread use of drug-eluting stents in patients with coronary artery disease (CAD) is hampered by unequal regulations for reimbursement. Identification of patients with maximal benefit from this technology may be achieved by assessing long-term clinical outcome after implantation of uncoated bare metal stents.

PATIENTS AND METHODS

A consecutive series of 1,000 patients with CAD treated with bare metal coronary stents of various designs from January 1995 to December 1995 was retrospectively followed over 4 years. The primary end points of the study were major adverse cardiac events.

RESULTS

The mean age of patients was 62 +/- 10.3 years, 77.5% were male, and 18% were diabetic. Clinical follow-up was obtained in 821 patients (82.1%) after 4.6 +/- 1.1 years. During this period of time, 31.8% were admitted for repeat PCI, 15.1% underwent CABG operation, 3.5% had myocardial infarctions, and 3.7% died. At 4 years, 46.3% of diabetic patients survived without event versus 57.6% of nondiabetic patients (P < 0.05). Patients with CAD I survived without event in 65.3% versus 54.0% of patients with CAD II and 48.5% of patients with CAD III (P < 0.02).

CONCLUSION

Implantation of uncoated stents provides the worst long-term clinical outcome in patients with diabetes and those with multivessel CAD. Both groups of patients appear to be primary candidates for the use of drug-eluting stents.

A randomized trial of polytetrafluoroethylene-membrane-covered stents compared with conventional stents in aortocoronary saphenous vein grafts

We compared a conventional stent (Jostent Flex, Jomed GmbH, Rangendingen, Germany) with a polytetrafluoroethylene (PTFE)-membrane-covered stent (Jostent Stentgraft) in patients undergoing intervention of a stenosis in an obstructed vein graft. The use of stents improved results of percutaneous revascularization of obstructed vein grafts, but did not demonstrate the reduced elevated restenosis rate. In addition, long-term clinical event rate is still high compared with intervention in native vessels. Observational studies suggested that stents covered with a PTFE membrane might be associated with a low complication and restenosis rate in venous bypass grafts. This prospective multicenter study included a total of 211 patients who were randomly assigned to receive either a Flex stent or Stentgraft. The primary end point was binary restenosis rate at six months by core lab quantitative coronary angiography. Acute success and procedural events were comparable between the two groups. Restenosis rate was not significantly different between the Flex (20%) and the Stentgraft (29%) groups (p = 0.15), although there was a nonsignificant trend toward a higher late occlusion rate in the Stentgraft group (7% vs. 16%, p = 0.069) at follow-up. Likewise, after a mean observation period of 14 months, cumulative event rates (death, myocardial infarction, or target lesion revascularization) were comparable in the two groups (31% vs. 31%, p = 0.93). This controlled trial does not indicate a superiority of the PTFE-membrane-covered Stentgraft compared with a conventional stent with respect to acute results, restenosis, or clinical event rates.

Comparison of stainless steel stents coated with turbostratic carbon and uncoated stents for percutaneous coronary interventions

BACKGROUND

Stent coating with turbostratic carbon was supposed to minimize the local inflammatory response after stent implantation and to thereby also reduce the rates of restenosis and clinical events.

METHODS AND RESULTS

From October, 1999 to February, 2002, a total of 329 patients with symptomatic coronary artery disease (CAD) eligible for single-lesion PCI were randomized for implantation of either a CarboStent (C; n = 168) or a stainless-steel stent (S; n = 161). The stainless-steel stents were Tristar stents in 60.2%, Tetra stents in 17.4% and Penta stents in 22.4%. Both groups showed no differences in baseline clinical and angiographic characteristics. Angiographic follow-up (FU) was obtained after 6 months in 287 patients (87.2%), clinical FU in 295 patients (89.7%). With the exception of a smaller post-procedure minimal luminal diameter (MLD) in the C group (2.59 0.43 mm versus 2.72 0.46 mm in the S group; p = 0.01), there were no significant differences between the C and S groups in lesion length (10.28 4.45 mm versus 10.37 4.79 mm, respectively), reference diameter (2.92 0.59 mm versus 2.89 0.53 mm, respectively), pre-procedure MLD (0.77 0.36 mm versus 0.84 0.36 mm, respectively), MLD at FU (1.67 0.64 mm versus 1.68 0.57 mm, respectively), late loss (0.93 0.63 mm versus 1.05 0.59 mm, respectively), late loss index (0.51 0.32 versus 0.57 0.32, respectively) and restenosis rate (18.1% versus 20.6%, respectively). There were also no significant differences regarding major adverse cardiac events (MACE) between the C and S groups, i.e., occurrence of death (0% versus 0.7%, respectively), myocardial infarction (0% versus 0.7%, respectively), coronary artery bypass graft (0.7% versus 1.4%, respectively) and target lesion revascularization (16.4% versus 21.5%, respectively).

CONCLUSION

Coronary stents coated with turbostratic carbon gave no clinically relevant reduction of in-stent restenosis and MACE rates when compared to uncoated stents.

Regulation of the serotonin transporter by interacting proteins

The serotonin transporter (SERT) plays a critical role in the maintenance of normal neurotransmission by serotonin [5-hydroxytryptamine (5-HT)]. Recent evidence suggests that SERT and other neurotransmitter transporters are tightly regulated. Activation of protein kinase C results in a decrease in SERT-mediated 5-HT uptake, which is due to an internalization of the transporter. However, to date little is known about the mechanism and proteins involved in the down-regulation of the transporter. One candidate SERT-regulatory protein is the SNARE (soluble N-ethylmaleimide-sensitive factor-attachment protein receptor) protein, syntaxin 1A (Syn1A), which has recently been implicated in the regulation of ion channels as well as the SERT-related gamma-aminobutyric acid- and glycine-transporters. Using 5-HT uptake assays, confocal microscopy and glutathione S-transferase (GST) pull-down assays we showed that Syn1A also interacts with SERT and alters the subcellular localization of the transporter, resulting in a reduction of 5-HT transport. In addition, we have used the yeast two-hybrid system to search for novel regulatory proteins that interact with the cytoplasmic N-terminal domain of SERT. By screening rat brain cDNA library we have identified six potential SERT-binding proteins. Here we also present progress towards the elucidation of the biological relevance of these proteins and their potential role for the regulation of the serotonin transporter.

Signals from skin mechanoreceptors used in control of a hand grasp neuroprosthesis

We used signals from tactile mechanoreceptors in the skin of the index finger, recorded with an implanted cuff electrode, to automatically control grasp force in a hand grasp neuroprosthesis. Phasic events in the recorded nerve signal, related to mechanical events on the skin, were used to adjust electrical stimulation of hand muscles without any prior knowledge about muscle strength and properties of a held object. A simulated eating task was used to evaluate the hand grasp neuroprosthesis. When using the neuroprosthesis with feedback from natural sensors, the average grasp force could be reduced in comparison to not using feedback. Reducing grasp force is considered a major factor to decrease muscle fatigue, allowing a prolonged use of the hand grasp neuroprosthesis.

The Virtual Brain Project--development of a neurosurgical simulator

As a joined project between Aalborg University and Aalborg Hospital Denmark, a neuro-surgical simulator is being developed. In this paper the objective of the project is outlined and an overview of the research activities within the project is given. Focus is on 3D modelling of the brain, deformable models and the development of two demonstrators, including one for training of punctuation of ventricle using visual and haptic feedback.

Extracranial-intracranial bypass surgery in cerebrovascular diseases

Since the report from the International Study on extracranial-intracranial bypass was presented in 1985, an abrupt stop to almost all bypass surgery was introduced. The clear goals of the bypass study to reduce repeated strokes based on extracranial-intracranial bypass could not be documented. This review emphasizes the drawbacks of this previous study and why its conclusions were too sweeping, including statements that the study could not validate. The present status on cerebral hemodynamics and possible augmentations of reduced cerebral vascular reserve using extracranial-intracranial bypass are given. It is concluded that in hemodynamic proven cases extracranial-intracranial bypass may definitely benefit the patients. This group of patients, among all stroke victims in the International Study, could not be deducted due to the study design. The high frequency of repeated serious strokes occurring among patients with hemodynamic insufficiency and its prevention by bypass surgery is documented. The right operation was carried out among a large group of `wrong` patients. The prevention of repeated strokes that an extracranial-intracranial bypass allows us today, indicates that this operative method should also be possibly applied in the Kingdom under well defined hemodynamic circumstances.

Extracranial-intracranial bypass surgery in cerebrovascular diseases

Since the report from the International Study on extracranial-intracranial bypass was presented in 1985, an abrupt stop to almost all bypass surgery was introduced. The clear goals of the bypass study to reduce repeated strokes based on extracranial-intracranial bypass could not be documented. This review emphasizes the drawbacks of this previous study and why its conclusions were too sweeping, including statements that the study could not validate. The present status on cerebral hemodynamics and possible augmentations of reduced cerebral vascular reserve using extracranial-intracranial bypass are given. It is concluded that in hemodynamic proven cases extracranial-intracranial bypass may definitely benefit the patients. This group of patients, among all stroke victims in the International Study, could not be deducted due to the study design. The high frequency of repeated serious strokes occurring among patients with hemodynamic insufficiency and its prevention by bypass surgery is documented. The right operation was carried out among a large group of "wrong" patients. The prevention of repeated strokes that an extracranial-intracranial bypass allows us today, indicates that this operative method should also be possibly applied in the Kingdom under well defined hemodynamic circumstances.

Components of the RP4 conjugative transfer apparatus form an envelope structure bridging inner and outer membranes of donor cells: implications for related macromolecule transport systems

During bacterial conjugation, the single-stranded DNA molecule is transferred through the cell envelopes of the donor and the recipient cell. A membrane-spanning transfer apparatus encoded by conjugative plasmids has been proposed to facilitate protein and DNA transport. For the IncPalpha plasmid RP4, a thorough sequence analysis of the gene products of the transfer regions Tra1 and Tra2 revealed typical features of mainly inner membrane proteins. We localized essential RP4 transfer functions to Escherichia coli cell fractions by immunological detection with specific polyclonal antisera. Each of the gene products of the RP4 mating pair formation (Mpf) system, specified by the Tra2 core region and by traF of the Tra1 region, was found in the outer membrane fraction with one exception, the TrbB protein, which behaved like a soluble protein. The membrane preparation from Mpf-containing cells had an additional membrane fraction whose density was intermediate between those of the cytoplasmic and outer membranes, suggesting the presence of attachment zones between the two E. coli membranes. The Tra1 region is known to encode the components of the RP4 relaxosome. Several gene products of this transfer region, including the relaxase TraI, were detected in the soluble fraction, but also in the inner membrane fraction. This indicates that the nucleoprotein complex is associated with and/or assembled facing the cytoplasmic site of the E. coli cell envelope. The Tra1 protein TraG was predominantly localized to the cytoplasmic membrane, supporting its potential role as an interface between the RP4 Mpf system and the relaxosome.

French transportable laser ranging station: scientific objectives, technical features, and performance

The French Transportable Laser Ranging Station (FTLRS) is a highly mobile satellite laser ranging (SLR) system unit that weighs 300 kg and is housed in eight containers. This telemetry laser station is dedicated to the tracking of geodetic satellites equipped with retroreflectors. There are fascinating uses in the geosciences for such a system: in tectonics, oceanography, terrestrial reference frames, and precise positioning. The idea is to use a very small 13-cm-diameter telescope installed on a motorized mount and derived from a geodetic motorized theodolite of high precision. The laser is also compact, and the use of an avalanche photodiode makes detection possible at a single photoelectron level. On-site installation of this new SLR system is fast, and the system's routine operation is quite automated. It started its operational phase in late 1996. At present, it can track satellites at altitudes of as much as 3000 km and is designed to range to the Laser Geodynamic Earth Orientation Satellite (LAGEOS) at 6000 km in a further step. The standard error of individual measurements during the first observation campaign in Corsica is estimated to be of the order of 2-3 cm. Since then, significant improvements have been implemented. A technical description of the FTLRS is given, and the main results of the Corsica campaign are summarized.

Neuronavigation

The fact that the visualization process has been deferred since MRI and CT scanning have become the imaging standards for today's neurosurgeons has led to the importance of developing a tool for testing and teaching young pediatric neurosurgeons in the future. Navigation and teaching in a virtual reality model seems a sound solution.