1 – Investigation

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Vascular Centers in 2008: team approach to medicine, surgery and endovascular intervention
Chairman: R Simkin (Argentina)
Lecture by P Gloviczki (USA)

In the spirit of the words of Dr. William P. Mayo—“No one is big enough to be independent of others”—P Gloviczki described the new model of multidisciplinary teams in the treatment of vascular patients. With this aim, P Gloviczki and the Mayo Clinic created the Mayo Clinic Gonda Vascular Center in 1991. At the center patients with vascular diseases receive high-quality medical, endovascular, and open surgical treatment by appropriate experts working as a coordinated team. The principal advantages are that the attention is disease- and patient-centered and the needs of the patients come first in a multidisciplinary, integrated approach to the patient care, education, and research. This is an integrated program with participation of all disciplines involved in vascular care.

A major project developed by the Mayo Clinic Gonda Vascular Center was the Integrated Endovascular Program. Specialists from interventional cardiology, vascular and interventional radiology, vascular medicine, and vascular surgery participated in this exciting project. The aim was to build a premier endovascular program designed to provide every patient with the best care every day through integrated clinical practice, education, and research. The success of this strategic plan depends entirely on the full support, expertise, and collaboration of each participant .

Gloviczki P. Vascular and endovascular surgeons: the vascular specialist for the 21sth century and beyond. J Vasc Surg 2006;43:412-21.

Investigations for carotid endarterectomy and carotid angioplasty stenting
Moderators: F Benedetti Valentini (Italy), PL Antignani (Italy)
Participants: PL Antignani (Italy), C Liapis (Greece), B Gossetti (Italy), O Martinelli (Italy), E Hussein (Egypt), C Setacci (Italy), F Benedetti Valentini (Italy).

This session consisted of a number of presentations from several countries dealing with the value of different diagnostic methods in the fields of carotid endarterectomy (CEA) and carotid angioplasty stenting (CAS). PL Antignani emphasized that the cost of a general screening for carotid disease is high, the absolute risk of stroke in asymptomatic stenosis is low, and that CEA performed with surgical morbidity and mortality <3% would prevent one stroke in five years.

High-risk patients have to be identified by evaluating risk factor, i.e., ageing, cervical bruits, peripheral arterial disease. Carotid ultrasonography and magnetic resonance are similar, but cost, availability, and local experience are important in choosing the best test. Duplex screening can result in many false positives. Screening for bypass surgery is recommended among patients who are 65 years or older and have other significant risk factors, symptomatic peripheral vascular disease, a history of abdominal aortic aneurysm in a setting of cerebrovascular disease, restenosis, restenosis following carotid stenting, patients who receive radiation therapy for head and neck cancer, patients with a history of retinal ischemic events.

B Gossetti discussed plaque morphology and emphasized the role of color flow duplex imaging and its efficacy in establishing the degree of stenosis, echogenicity, surface contour. The introduction of computer-assisted objective grading solved the problem of inter and intra-observer agreement on plaque echogenicity which was high in few comparative studies. In patients with high-grade carotid stenosis, ultrasound study using contrast enhancement is a sensitive method of detecting pseudo-occlusion of the internal carotid. Radiological imaging obtained by computed tomography or magnetic resonance imaging allows complete evaluation of the aortic arch, of the origin of carotid arteries and of intra-cranial vessels, avoiding the use of angiography. Microembolic events and strokes are the major drawback of CEA and CAS and may be investigated by transcranial Doppler, which allows good monitoring of blood flow changes and of microembolic signals in the middle cerebral artery. O Martinelli reported her personal experience in transcranial Doppler monitoring on 1326 CAS and 157 CEA. In CAS, the rate of microembolic events was 54.2% during cannulation + filter positioning (2.7% neurological events), 64.3% during peripheral transluminal angioplasty (PTA) and/or stenting and ballooning (1.2% neurological events). In CEA, microembolic events were detected in 74% of cases and the highest incidence during dissection and 30’ after declamping. Microembolic events were symptomatic in 18% cases of CEA and 3.9% cases of CAS. For C Setacci the accuracy of carotid ultrasound has not been well established in predicting intrastent restenosis (ISR) after carotid stenting (CAS). The aim of this study was to determine different degrees of ISR using ultrasound velocity criteria compared with angiography. After CAS, each patient underwent angiography to measure ISR (NASCET method) which was compared with peak systolic velocity (PSV) end-diastolic velocity (EDV), and the ratio between PSV values of the internal carotid artery and common carotid artery (ICA/CCA). This was done within 48 hours, thus creating a baseline value. An ultrasound examination was performed at 30 days, 3, 6, 9, and 12 months. Patients with a more than 3-fold increase in PSV above baseline or with PSV >200 cm/s underwent angiography. RESULTS: 814 CAS procedures, 6427 ultrasound examinations and 1123 angiographies were performed. ISR > 70% and ISR >50% were detected, respectively, in 22 and 73 patients. We defined velocity criteria for grading carotid ISR: PSV <104 cm/s with <30% stenosis; PSV:105 to 174 cm/s with 30% to 50% stenosis; PSV:175 to 299 cm/s with 50% to 70% stenosis; PSV >300 cm/s, EDV >140 cm/s, and ICA/CCA >3.8 with >70% stenosis. Receiver operator characteristic (ROC) curves for ISR >or=70% were, respectively, for PSV, EDV, and ICA/CCA: 0.99, 0.98, and 0.99. Conclusions: ultrasound grading of carotid ISR can guarantee a correct follow-up after CAS if new customized velocity criteria are validated by skilled operators using a specific follow-up protocol in a certified laboratory. F Benedetti Valentini summarized the cases when the use of color-coded duplex sonography (CD) is not sufficient: unclear color-coded duplex sonography in the presence of heavy calcifications or discrepancy of symptoms versus color-coded duplex sonography. Pseudocclusion with the patency of distal internal carotid also suggests the use of transcranial Doppler. Finally in occlusion of the distal internal carotid with ocular/cerebral symptoms, external carotid stenosis, anomalies/lesions of supraortic trunks, intracranial aneurysm >7 mm, associated nonvascular disease of the neck, the use of angio computed tomography (aCT) and nuclear magnetic resonance (MR) is recommended.