Management of Patients with Carotid Artery Stenosis

Abstract : A stenosis of the internal carotid artery may cause 10-20% of all ischemic strokes. Duplex ultrasound is the diagnostic cornerstone, and CT angiography or MR angiography may be used to confirm the severity of the stenosis or prior to revascularization. Catheter-based digital subtraction angiography is rarely needed for diagnostic purposes. In symptomatic patients, carotid revascularization is indicated in the presence of a stenosis ≥ 50%. In asymptomatic patients, the indication for revascularization based on randomized trials is given at ≥ 60% stenosis, as long as the estimated perioperative death or stroke risk is < 3%. In clinical practice, however, asymptomatic stenoses are usually treated only if luminal narrowing exceeds 70-80% and the patient has a life expectancy of at least 5 years. The choice of the revascularization strategy (endarterectomy vs. stenting) should be based on the patient's surgical risk profile and on the locally available expertise. Independently of the revascularization option, carotid artery stenosis patients remain at risk of cardiovascular events because of the high prevalence of associated coronary artery disease. A broad disease management focusing on risk factor and lifestyle modification may impact quality and duration of life of these patients to a greater extent than the revascularization procedure itsel

Il Presidente della Repubblica nell'evoluzione della forma di governo

La tesi si propone di definire il ruolo assunto dal Presidente della Repubblica nell’odierno assetto della forma di governo, influenzata dal crollo dei partiti politici e dalla diffusione del fenomeno dell’anti- politica, dalle trasformazioni della legge elettorale e dall’influenza dell’Unione Europea e dell’andamento del mercati sulle decisioni politiche interne al sistema. In questo contesto la figura del Presidente suscita un rinnovato interesse e con essa la contrapposizione tra le due teorie classiche che definiscono il Capo dello Stato l’una come potere neutro, l’altra come portatore di un autonomo indirizzo politico- costituzionale. Esposti i termini delle stesse la trattazione procede, nella parte centrale, all’analisi di alcuni importanti poteri presidenziali considerati particolarmente indicativi al fine del presunto esercizio di autonomi poteri d’indirizzo: lo scioglimento delle Camere, la formazione del Governo e la scelta dei suoi Ministri, il rinvio della legge, i messaggi di accompagnamento alla legislazione, il rinvio e il rifiuto dei decreti legge, il controllo sulle leggi di conversione; rilevante appare inoltre un’analisi dei conflitti di attribuizione che hanno visto coinvolto, anche in tempi molto recenti, il Capo dello Stato. La trattazione si propone una esposizione tecnico- giuridica degli istituti al fine di garantire una lettura critica delle vicende politico istituzionali più recenti, e di comprendere se l’operato presidenziale possa dirsi o meno consonante al dettato costituzionale. Nella parte conclusiva, constatata l’effettiva ambiguità della figura in esame, si svolge una riflessione sul rapporto tra i poteri da essa esercitati e le diverse tipologie di responsabilità di cui il Presidente è chiamato a rispondere. Nell’ottica di quella dottrina che non ritiene equilibrato tale rapporto si procede ad una succinta esposizione del modello semipresidenziale e ad una valutazione circa l’applicazione dello stesso nel nostro sistema. Nella riflessione conclusiva si esclude di poter ridurre la figura presidenziale negli schemi dottrinali inizialmente esposti: il Presidente ricopre oggi un ruolo di garanzia attiva che lo chiama talvolta ad assumere posizioni incisive anche all'interno di procedimenti molto complessi ai fini degli equilibri politici, spesso contestate, ma sempre finalizzate a garantire la continuità istituzionale e la salvaguardia dell’unità nazionale e non certamente a sovvenzionare un presunto e ambiguo autonomo indirizzo

Platelet Inhibition in Percutaneous Coronary Interventions

Abstract : Mechanical disruption of atherosclerotic plaques at the time of percutaneous coronary intervention (PCI) is a potent stimulus for arterial thrombosis. Since platelets play a crucial role in the cascade of clot formation, platelet inhibition is an essential step for successful PCI. Aspirin remains the cornerstone of any antithrombotic regimen in the interventional setting. The addition of a thienopyridine is mandatory following stenting to prevent thrombosis of the device. Whenever possible, patients undergoing PCI should be pretreated with clopidogrel and the drug should be continued for up to 1 year. Glycoprotein IIb/IIIa antagonists should be administered in high-risk patients, such as those with acute coronary syndromes, diabetes, or complex coronary anatom

Carotid artery stenting vs. endarterectomy

Randomized clinical trials have demonstrated that carotid endarterectomy (CEA) is superior to medical management for stroke prevention in patients with symptomatic and, to a lesser degree, asymptomatic internal carotid artery stenosis. However, large-scale registries have shown that the adverse event rates following CEA are commonly higher than observed in the trials. In the last decade, carotid artery stenting (CAS) has emerged as a less invasive alternative to surgery. In order to address the efficacy of CAS, we performed a meta-analysis of 10 randomized trials comparing CAS with CEA in 4648 mainly symptomatic patients. The analysis showed that CAS was associated with a statistically significant increased death or stroke rate at 30 days compared with CEA (odds ratio 1.60, 95% confidence interval 1.26-2.02). However, most of the trials had inadequate requirements in terms of endovascular expertise and did not mandate the use of emboli protection devices. Beyond 30 days, long-term follow-up of the trials previously reported suggest that both revascularization techniques are equivalent in terms of stroke prevention. Conversely, large-scale high-quality CAS registries—mostly with independent neurological assessment and clinical event committee adjudication—have reported results in the range of current recommendation for CEA in over 20 000 patients, despite the fact that the majority of patients were at high risk for surgery. Until further data become available, the performance of CAS should be limited to protocols or centres of excellence and targeted especially to patients at high risk for surger

Perancangan Pesawat Tanpa Awak (Unmanned Aerial Vehicle) untuk Pencitraan Lokasi Siaga Bencana di Sumatera Barat

Dalam penelitian ini dilakukan sebuah perancangan Pesawat Tanpa Awak (Unmanned Aerial Vehicle/ UAV). Penelitian ini diawali dengan merumuskan konsep rancangan yang sesuai dengan wilayah pencitraan lokasi siaga bencana di Sumatera Barat. Hasil dari perumusan konsep rancangan akan dilanjutkan kedalam tahapan disain berikutnya sehingga menghasilkan detail design yang akan menjadi acuan dalam proses rancang bangun. Penelitian ini difokuskan pada perancangan UAV jenis wingspan yang dilengkapi teknologi pencitraan. Dimulai dengan melakukan proses perancangan UAV meliputi disain model pesawat (fuselage, wing, nose, horizontal stabilizer, vertical stabilizer, aeleron, elevator, ruder dan landing gear) dan menguji karakteristik aerodinamika. Pada makalah ini disajikan tahapan perancangan UAV dengan pendekatan Computational Fluid Dynamics (CFD). Dari hasil perancangan didapatkan bentuk airfoil dan disain UAV yang mampu memenuhi spesifikasi disain yaitu mampu membawa beban sebesar 1.75 kg dengan kecepatan jelajah 12 m/s

Nachbehandlung nach medikamentös beschichteten Stents

Zusammenfassung: Die medikamentös beschichteten Stents, die sog. "drug-eluting stents" (DES), haben die Restenoserate und damit die Notwendigkeit einer erneuten Revaskularisation nach perkutaner koronarer Intervention (PCI) um 50-71% gesenkt. Sie werden zunehmend bei anatomisch schwierigen Verhältnissen, wie langen, dünnkalibrigen Gefäßen, Totalverschlüssen und Bifurkationsstenosen, eingesetzt. Eine seltene, jedoch folgenschwere Komplikation der Stenteinlagen ist die Stentthrombose, eine partielle oder vollständige Obstruktion des Implantats. Die zunehmend komplexen Interventionen mittels DES, die potentiell prothrombotische Wirkung der antiproliferativen Substanzen und die verlangsamte Endothelialisierung verlängern und erhöhen theoretisch das Stentthromboserisiko nach Implantation eines DES. Eine 1-jährige doppelte plättchenhemmende Therapie wird deshalb zur Nachbehandlung empfohlen. Für den Nutzen einer routinemäßigen doppelten plättchenhemmenden Therapie über 1 Jahr hinaus fehlen zurzeit die Grundlagen. Nichtkardiale chirurgische Eingriffe sollten für 1 Jahr aufgeschoben werden oder nach Möglichkeit unter dem Schutz von Acetylsalicylsäure durchgeführt werde

Percutaneous coronary intervention in diabetic patients with non-ST-segment elevation acute coronary syndromes

Key pathophysiologic mechanisms of diabetes-related coronary disease include inflammation and a prothrombotic state. In the setting of non-ST-segment elevation acute coronary syndromes diabetic patients are at high risk for subsequent cardiovascular events. At the same time, they derive greater benefit than non-diabetic counterparts from aggressive antithrombotic therapy, early coronary angiography, and stent-based percutaneous coronary intervention. The mainstays of antithrombotic therapy for diabetic patients undergoing percutaneous revascularization include aspirin, clopidogrel, platelet glycoprotein IIb/IIIa receptor antagonists, and heparin or low-molecular-weight heparin. Despite dramatic reduction in restenosis conferred by drug-eluting stents, diabetic patients remain at increased risk for repeat revascularization. More efforts are needed both in terms of local drug elution as well as systemic pharmacologic therapies to further contain the excessive neointimal proliferation that characterizes the diabetic response to vascular injur