Wall shear stress in the development of in-stent restenosis revisited. A critical review of clinical data on shear stress after intracoronary stent implantation

The average wall shear stress (WSS) is in 1 Pa range in coronary arteries, while the stretching effect of an implanted coronary stent can generate up to 3 × 105 times higher circumferential stress in the vessel wall. It is widely accepted that WSS plays a critical role in the development of restenosis after coronary stent implantation, but relevant clinical endpoint studies are lack­ing. Fluid dynamics modeling suggests an association between WSS and intimal hyperplasia, however, such an association is not established when the compensating healing process becomes an overshoot phenomenon. This review summarizes available clinical results and concepts of potential clinical importance

A kalcium tranziens kialakulásának mechanizmusa működő szívben = Development of the calcium transient in the beating heart

Kutatásaink a ciklikus intracelluláris kalciumion koncentráció (Ca2+i) változásait kialakító transzport folyamatok felderítésére irányultak normál és kardiomiopátiás szívben. A mért primer jel a Ca2+i tranziens volt, melynek kvantitív analízisére matematikai modellt fejlesztettünk ki. Ennek segítségével lehetővé vált a rianodin csatorna és a SERCA2a kinetikai paramétereinak kiszámítása. Megfigyeléseink szerint a posztiszkémiás szívben a tartósan megemelkedett Ca2+i szint kontraktúrát, valamint a PLA2 aktiválásával membrán degradációt okoz. Ezek a károsodások hő-sokk előkezeléssel részlegesen kivédhetők. További megfigyelésünk szerint a diabéteszes és toxikus kardiomiopátia Ca2+i felszabadulási és szekvesztrációs zavarokat okoz, valamint a nukleáris poli(ADP-ribóz)polimeráz enzim gátlásával a toxikus kardiomiopátia ezen hatásai a Ca2+i homeosztázisra mérsékelhetők. Összefoglalva; a T038121 sz. OTKA támogatás segítségével jelentős előrelépést tettünk a myocardium Ca2+i tranziensét kialakító mechanizmusok feltérképezésében mind normál, mind patofiziológiás körülmények között. | During the grant period of 2002-2005 our research focused on the delineation of the processes responsible for the cyclic changes of the intracellular calcium concentration (Ca2+i) in the normal and diseased heart. A mathematical model was developed to allow the quantitative analysis of the observed Ca2+i signal. Using this novel mathematical approach we have calculated the kinetic parameters of the sarcoplasmic reticulum calcium release channel (RyR2) and SERCA2a. We have observed that the persistent increase in end-diastolic Ca2+i is associated with contracture of the myocardium and activation of PLA2 resulting in membrane degradation. These pathological events can be ameliorated with heat shock pretreatment. We have found that cardiomyopathy of either diabetes or toxic origin results in malfunction of Ca2+ release and sequestration. We have also shown that the disruptive effects of toxic cardiomyopathy on Ca2+i handling can be suppressed with the inhibition of the nuclear enzyme ply(ADP-ribose)polymerase. In summary; funds provided by OTKA T038121 spawned major progress in our research to delineate the processes involved in Ca2+i handling both under normal and pathological circumstances

Guided de-escalation of antiplatelet treatment in patients with acute coronary syndrome undergoing percutaneous coronary intervention (TROPICAL-ACS): a randomised, open-label, multicentre trial

BACKGROUND: Current guidelines recommend potent platelet inhibition with prasugrel or ticagrelor for 12 months after an acute coronary syndrome managed with percutaneous coronary intervention (PCI). However, the greatest anti-ischaemic benefit of potent antiplatelet drugs over the less potent clopidogrel occurs early, while most excess bleeding events arise during chronic treatment. Hence, a stage-adapted treatment with potent platelet inhibition in the acute phase and de-escalation to clopidogrel in the maintenance phase could be an alternative approach. We aimed to investigate the safety and efficacy of early de-escalation of antiplatelet treatment from prasugrel to clopidogrel guided by platelet function testing (PFT). METHODS: In this investigator-initiated, randomised, open-label, assessor-blinded, multicentre trial (TROPICAL-ACS) done at 33 sites in Europe, patients were enrolled if they had biomarker-positive acute coronary syndrome with successful PCI and a planned duration of dual antiplatelet treatment of 12 months. Enrolled patients were randomly assigned (1:1) using an internet-based randomisation procedure with a computer-generated block randomisation with stratification across study sites to either standard treatment with prasugrel for 12 months (control group) or a step-down regimen (1 week prasugrel followed by 1 week clopidogrel and PFT-guided maintenance therapy with clopidogrel or prasugrel from day 14 after hospital discharge; guided de-escalation group). The assessors were masked to the treatment allocation. The primary endpoint was net clinical benefit (cardiovascular death, myocardial infarction, stroke or bleeding grade 2 or higher according to Bleeding Academic Research Consortium [BARC]) criteria) 1 year after randomisation (non-inferiority hypothesis; margin of 30%). Analysis was intention to treat. This study is registered with ClinicalTrials.gov, number NCT01959451, and EudraCT, 2013-001636-22. FINDINGS: Between Dec 2, 2013, and May 20, 2016, 2610 patients were assigned to study groups; 1304 to the guided de-escalation group and 1306 to the control group. The primary endpoint occurred in 95 patients (7%) in the guided de-escalation group and in 118 patients (9%) in the control group (pnon-inferiority=0.0004; hazard ratio [HR] 0.81 [95% CI 0.62-1.06], psuperiority=0.12). Despite early de-escalation, there was no increase in the combined risk of cardiovascular death, myocardial infarction, or stroke in the de-escalation group (32 patients [3%]) versus in the control group (42 patients [3%]; pnon-inferiority=0.0115). There were 64 BARC 2 or higher bleeding events (5%) in the de-escalation group versus 79 events (6%) in the control group (HR 0.82 [95% CI 0.59-1.13]; p=0.23). INTERPRETATION: Guided de-escalation of antiplatelet treatment was non-inferior to standard treatment with prasugrel at 1 year after PCI in terms of net clinical benefit. Our trial shows that early de-escalation of antiplatelet treatment can be considered as an alternative approach in patients with acute coronary syndrome managed with PCI. FUNDING: Klinikum der Universitat Munchen, Roche Diagnostics, Eli Lilly, and Daiichi Sankyo

Comparison of Platelet Function Guided Versus Unguided Treatment With P2Y12 Inhibitors in Patients With Acute Myocardial Infarction (from the Hungarian Myocardial Infarction Registry)

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Commissioning Plan of the IFMIF-DONES Accelerator

IFMIF-DONES (International Fusion Materials Irradiation Facility- DEMO-Oriented Neutron Early Source) - a powerful neutron irradiation facility for studies and certification of materials to be used in fusion reactors - is planned as part of the European roadmap to fusion electricity. Its main goal will be to characterize and to qualify materials under irradiation in a neutron field similar to the one faced in a fusion reactor. The intense neutron source is produced by impinging deuterons, from high-power linear deuteron accelerator, on a liquid lithium curtain. The facility has accomplished the preliminary design phase and is currently in its detailed design phase. At the present stage, it is important to have a clear understanding of how the commissioning of the facility will be performed, especially the commissioning of a 5 MW CW deuteron beam, together with the lithium curtain and the beam optimization for the neutron irradiation. In this contribution, the present plans for the hardware and beam commissioning of the accelerator will be given, focusing on the most critical aspects of the tiered approach and on the integration of the procedure with the lithium and tests systems

Target Identification for Stereotactic Thalamotomy Using Diffusion Tractography

BACKGROUND: Stereotactic targets for thalamotomy are usually derived from population-based coordinates. Individual anatomy is used only to scale the coordinates based on the location of some internal guide points. While on conventional MR imaging the thalamic nuclei are indistinguishable, recently it has become possible to identify individual thalamic nuclei using different connectivity profiles, as defined by MR diffusion tractography. METHODOLOGY AND PRINCIPAL FINDINGS: Here we investigated the inter-individual variation of the location of target nuclei for thalamotomy: the putative ventralis oralis posterior (Vop) and the ventral intermedius (Vim) nucleus as defined by probabilistic tractography. We showed that the mean inter-individual distance of the peak Vop location is 7.33 mm and 7.42 mm for Vim. The mean overlap between individual Vop nuclei was 40.2% and it was 31.8% for Vim nuclei. As a proof of concept, we also present a patient who underwent Vop thalamotomy for untreatable tremor caused by traumatic brain injury and another patient who underwent Vim thalamotomy for essential tremor. The probabilistic tractography indicated that the successful tremor control was achieved with lesions in the Vop and Vim respectively. CONCLUSIONS: Our data call attention to the need for a better appreciation of the individual anatomy when planning stereotactic functional neurosurgery