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Sternberg K.,University of Rostock | Grabow N.,University of Rostock | Petersen S.,University of Rostock | Weitschies W.,University of Greifswald | And 4 more authors.
Current Pharmaceutical Biotechnology | Year: 2013

Beyond their originally sole mechanical function, current drug-eluting stents (DES) implement the concept of local drug delivery for the re-opening of stenotic arterial vessels, and for prevention of in-stent restenosis as one of the major limitations of conventional bare metal stents (BMS). Current DES consist of a permanent metallic stent platform and an active agent being released from a drug-incorporated polymer coating or a porous stent surface. Although DES have impressively demonstrated their capability of reducing in-stent restenosis, their safety remains under debate due to potential risks, such as delayed healing, late thrombosis and hypersensitivity demanding further development. Current advancements in the stent design address the stent platform, the pharmacologically active substance and/or the drug carrier. For instance, novel biocompatible absorbable stent platforms and drug carriers are developed and novel drugs with a differential effect on vascular endothelial and smooth muscle cells, providing efficient inhibition of muscle cells without altering the endothelial cell function, are identified. Moreover, biofunctionalization of the stent's surface with capture molecules for endothelial progenitor cells are under investigation in order to achieve an in situ endothelialization of the implant. In this context, this review paper discusses the current advances in coronary stent technology with a special focus on novel stent platforms, drugs and stent coatings for the prevention of restenosis and improvement of biocompatibility. © 2013 Bentham Science Publishers.

Herschel M.,University of Tubingen | Naumann F.,Hasso Plattner Institute For Softwaresystemtechnik | Szott S.,Konrad Zuse Zentrum fur Informationstechnik Berlin | Taubert M.,BIOTRONIK SE and Co. KG
IEEE Transactions on Knowledge and Data Engineering | Year: 2012

Duplicate detection determines different representations of real-world objects in a database. Recent research has considered the use of relationships among object representations to improve duplicate detection. In the general case where relationships form a graph, research has mainly focused on duplicate detection quality/effectiveness. Scalability has been neglected so far, even though it is crucial for large real-world duplicate detection tasks. We scale-up duplicate detection in graph data (ddg) to large amounts of data and pairwise comparisons, using the support of a relational database management system. To this end, we first present a framework that generalizes the ddg process. We then present algorithms to scale ddg in space (amount of data processed with bounded main memory) and in time. Finally, we extend our framework to allow batched and parallel ddg, thus further improving efficiency. Experiments on data of up to two orders of magnitude larger than data considered so far in ddg show that our methods achieve the goal of scaling ddg to large volumes of data. © 2012 IEEE.

Shanmugam N.,St Georges Healthcare NHS Trust | Boerdlein A.,BIOTRONIK SE and Co. KG | Proff J.,BIOTRONIK SE and Co. KG | Ong P.,St Georges Healthcare NHS Trust | And 5 more authors.
Europace | Year: 2012

AimsUncertainty exists over the importance of device-detected short-duration atrial arrhythmias. Continuous atrial diagnostics, through home monitoring (HM) technology (BIOTRONIK, Berlin, Germany), provides a unique opportunity to assess frequency and quantity of atrial fibrillation (AF) episodes defined as atrial high-rate events (AHRE).Methods and resultsProspective data from 560 heart failure (HF) patients (age 67 ± 10 years, median ejection fraction 27) patients with a cardiac resynchronization therapy (CRT) device capable of HM from two multi-centre studies were analysed. Atrial high-rate events burden was defined as the duration of mode switch in a 24-h period with atrial rates of >180 beats for at least 1 or total of 14 min per day. The primary endpoint was incidence of a thromboembolic (TE) event. Secondary endpoints were cardiovascular death, hospitalization because of AF, or worsening HF. Over a median 370-day follow-up AHRE occurred in 40 of patients with 11 (2) patients developing TE complications and mortality rate of 4.3 (24 deaths, 16 with cardiovascular aetiology). Compared with patients without detected AHRE, patients with detected AHRE>3.8 h over a day were nine times more likely to develop TE complications (P 0.006). The majority of patients (73) did not show a temporal association with the detected atrial episode and their adverse event, with a mean interval of 46.7 ± 71.9 days (range 0194) before the TE complication.ConclusionIn a high-risk cohort of HF patients, device-detected atrial arrhythmias are associated with an increased incidence of TE events. A cut-off point of 3.8 h over 24 h was associated with significant increase in the event rate. Routine assessment of AHRE should be considered with other data when assessing stroke risk and considering anti-coagulation initiation and should also prompt the optimization of cardioprotective HF therapy in CRT patients.© The Author 2011.

Wollmann C.G.,Hospital of St. Polten Lilienfeld | Wollmann C.G.,Institute of Research on Ischemic Heart Diseases and Rhythmology | Steiner E.,Institute of Diagnostic Imaging | Vock P.,Hospital of St. Polten Lilienfeld | And 4 more authors.
Journal of Cardiovascular Magnetic Resonance | Year: 2012

Background: The purpose of this study was to evaluate the feasibility of the magnetic resonance (MR) conditional pacemaker (PM) system (Evia SR-T and DR-T with Safio S leads) under MR conditions. Methods. Patients with standard PM indications and Evia PM were eligible for enrollment in this single center prospective non-randomized pilot study. Patients underwent MR of the brain and lower lumbar spine at 1.5 Tesla. Atrial (RA) und ventricular (RV) lead parameters (sensing, pacing threshold [PTH], pacing impedance) were assessed immediately before (baseline follow-up [FU]) and immediately after MRI (1 st FU), after 1 month (2nd FU) and 3 months (3 rd FU). The effect of MR on serious adverse device effect (SADE) free-rate, on atrial and ventricular sensing (AS/VS; mV) and atrial (RA) and ventricular (RV) pacing thresholds (PTH; V/0.4 ms) were investigated between baseline and 2nd FU. Continuous variables are expressed as meanSD and were compared using paired Students t-test. A p<0.05 was considered significant. Results: Thirty-one patients were enrolled. One patient had to be excluded because of an enrollment violation. Therefore, data of 30 patients (female 12 [40%], age 7312 years, dual chamber PM 15 [50%]) were included in this analysis. No MR related SADE occurred. Lead measurements were not statistically different between the baseline FU and the 2nd FU (AS/VS at baseline 3.22.1/15.06.0, at 2nd FU 3.22.1/14.96.5; p=ns. RA-PTH/RV-PTH at baseline 0.680.18/0.780.22, at 2nd FU 0.710.24/0.780.22; p=ns). The presence of the permanent pacemakers led to MR imaging artifacts on diffusion weighted sequences of the brain, but did not affect other sequences (e.g. FLAIR and T2 weighted spin-echo images). Conclusion: The use of the MR conditional Evia PM in a MR environment under predefined conditions is feasible. No MR related SADEs nor clinically relevant changes in device functions occurred. © 2012 Wollmann et al.; licensee BioMed Central Ltd.

Joner M.,TU Munich | Radke P.W.,Universitatsklinik Schleswig Holstein | Byrne R.A.,TU Munich | Hartwig S.,BIOTRONIK SE and Co. KG | And 3 more authors.
Journal of Biomaterials Applications | Year: 2013

Despite advances in contemporary stent technology, in-stent restenosis (ISR) remains the major limitation following revascularization procedures. We developed a porcine model of ISR to specifically investigate the preclinical outcomes of a novel drug-eluting balloon (DEB) in this particular setting. Fifteen pigs received bare metal stents in each of the major coronary arteries for 28 days to induce neointimal growth. Following repeat angiography, animals were allocated to fourdifferent treatment groups. The control group consisted of a bare angioplasty catheter, while the Pantera Lux™ (3.0 μg/mm2 paclitaxel) (30 s inflation) was compared to two consecutive deployments of the Pantera Lux™ (60 s inflation each) and the commercial SeQuent® Please balloon (60 s inflation). Twenty-eight days following balloon deployment, the animals underwent repeat angiography and were subsequently sacrificed for histopathologic assessment. There was a trend in reduction of percent diameter stenosis in the DEB group versus control (13.9% vs. 20.4%), while longer inflation duration or consecutive DEB deployment had no additional growth-limiting effect. Neointimal thickness was reduced from 0.38 ± 0.13 to 0.30 ± 0.09 mm in the control versus DEB group. All DEB groups showed delayed vascular healing characterized by dose-dependent increases in fibrin deposition and neointimal cell vacuity. Investigation of DEB in a porcine model of ISR is feasible and more accurately represents human disease conditions. The magnitude of neointima suppression is lower than that observed in non-diseased animal models and is accompanied by delayed vascular healing. © The Author(s) 2012.

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