Hemocompatibility of carotid artery stents: alterations of the electrical parameters of erythrocyte cell membrane--a word of caution.

The hemocompatibility of standard surgical treatment of carotid artery disease through the insertion of metallic stents is investigated by means of radio wave dielectric spectroscopy technique that allows the measurements of the electrical parameters of the red blood cell membrane. Our measurements suggest that both the membrane permittivity and the membrane conductivity, which characterize the overall electrical behavior of the cell membrane, undergo an appreciable alteration of their standard values as a consequence of the stent insertion. These alterations persist over long period of time, up to 4 weeks. Even if these effects could not cause any evident damage at physiological or clinical level to the patient, the presence of a host response to the stent implant suggests that a full hemocompatibility has not yet reached, and a word of caution is necessary.

Doppler ultrasonography and exercise testing in diagnosing a popliteal artery adventitial cyst.

We describe popliteal arterial adventitial cystic disease which causes intermittent claudication in a young athletic man, with atypical manifestation, without loss of foot pulses on knee flexion nor murmur in the popliteal fossa. The findings obtained from Magnetic Resonance Imaging were non-diagnostic. The diagnosis resulted from Echo-Doppler ultrasonography along with peak exercise testing. Ultrasonography also provided useful physiopathological informations suggesting that a popliteal artery adventitial cyst can become symptomatic if muscle exertion increases fluid pressure within the cyst, enough to cause hemodynamically significant endoluminal stenosis. Rapid diagnosis is essential to prevent progressive claudication threatening limb viability. To guarantee this professional sportsman a reliable and durable outcome, instead of less aggressive management, we resected the involved arterial segment and interposed an autologous saphenous-vein graft.

Cerebral embolization during transcervical carotid stenting with flow reversal: a diffusion-weighted magnetic resonance study.

Transfemoral filter-protected carotid artery stenting (CAS) has emerged as a valid alternative to carotid surgery. To overcome the drawbacks of femoral access for CAS and reduce embolic load, some have proposed cervical access with internal carotid artery (ICA) flow reversal. In a series of patients at high risk for femoral access who underwent transcervical CAS with ICA flow reversal, we report clinical outcome and intraoperative embolization rates measured by diffusion-weighted magnetic resonance imaging (DW-MRI). A series of 48 patients were selected for transcervical CAS with carotid flow reversal from September 2004 to July 2007. The indications used for this technique were age >or=80 years, severe aortic and epiaortic vessel tortuosity, widespread calcification of aortic arch or epiaortic vessels, severe aortoiliac occlusive disease, large abdominal aortic aneurysm, and aortobifemoral prosthesis. During the procedure, no adjunctive maneuvers such as external carotid artery balloon occlusion were used. Of the 48 patients, 43 underwent preoperative and postoperative cerebral DW-MRI. The death/stroke rate in the 48 patients was 2.1% (one transient ischemic attack, one minor stroke, and no deaths). None of the procedures led to carotid dissections or access-site complications. Of the 43 patients who underwent DW-MRI, 16 new ischemic lesions were disclosed in six patients (13.9%), four (9.3%) of whom remained asymptomatic. All ischemic lesions were ipsilateral to the treated carotid artery. In patients at high risk for the transfemoral approach, transcervical carotid stenting with flow reversal achieves good technical and clinical results and seems able to reduce the incidence of postoperative DW-MRI ischemic lesions previously reported for transfemoral filter-protected CAS.

Are aortic endograft prostheses fully hemo-compatible? A dielectric spectroscopy investigation of the electrical alterations induced on erythrocyte cell membranes.

In this paper we present a new approach directed to ascertain the full hemo-compatibility of aortic endograft prostheses based on the measurement of the passive electrical parameters of the erythrocyte cell membrane. The red blood cell membrane, from an electric point of view, is characterized by an electrical permittivity, (s), which takes into account the structural charged organization of the lipid double layer, and by the electrical conductivity, sigma(s), which accounts for the ionic transport processes across the membrane. These parameters can be easily measured by means of a radiowave dielectric spectroscopy technique, analyzing the dependence of the electrical impedance of an erythrocyte suspension on the frequency of the applied electric field. In this preliminary report, we investigate the alterations induced, at a membrane level, by two different devices commonly employed for endovascular abdominal aortic aneurysm exclusion, i.e., Excluder and Zenith devices, implanted in ten patients. We observe, in all the cases investigated, a statistically significant increase of both the permittivity (s) and electrical conductivity sigma(s) of the erythrocyte membrane upon the prosthesis implant, this increase being higher than about 20% of the un-treated values. Moreover, these alterations remain roughly unaffected 30 days after surgery. These findings suggest that a complete hemo-compatibility of these prostheses is lacking, even if the observed alterations may not have a clinical relevance.

Metalloproteinase expression in carotid plaque and its correlation with plasma levels before and after carotid endarterectomy.

PURPOSE: To assess baseline and follow-up plasma concentrations of metalloproteinase-9 (MMP-9), MMP-2, and tissue inhibitor of metalloproteinase-2 (TIMP-2) in patients undergoing carotid thromboendarterectomy (TEA) in relation to tissue expression and diagnostic features. BASIC METHODS: Using sandwich enzyme-linked immunosorbent assay, plasma levels of enzymes were determined in 15 patients undergoing carotid TEA. Tissue sections were incubated with specific antibodies and fluorescence intensity was analyzed. PRINCIPAL FINDINGS: MMP-9 levels were higher in patients with carotid stenosis versus controls, significantly in those with cerebral lesions at neuroimaging. MMP-9 levels decreased in 93.4% of the patients at 1 month. MMP-2 levels tended to increase 30 days after surgery. TIMP-2 showed no difference. CONCLUSIONS: High concentrations of MMP-9 found in patients with carotid stenosis and cerebral lesions suggest that MMP-9 assay could be useful in the evaluation of all carotid lesions to help identify those at highest risk of a neurologic event.

Laryngeal and cranial nerve involvement after carotid endarterectomy.

CONCLUSIONS: Laryngeal and/or cranial nerve involvement after CEA surgery is not a rare condition, occurring in almost half of operated subjects. However, in most cases the functional deficit is transient and does not need any particular form of treatment. In this study, specific rehabilitative procedures were needed in only a relatively small number of cases (9%). A routine ENT examination has also proved to be extremely useful for detecting slight functional deficits which may occur following CEA surgery, bearing in mind that possible permanent lesions may require a rehabilitative procedure. OBJECTIVE: To identify, by means of a careful otolaryngologic examination, the incidence and degree of cranial nerve deficit related to carotid endarterectomy (CEA), starting from the first postoperative days. MATERIAL AND METHODS: A consecutive cohort of patients with symptomatic and asymptomatic carotid artery stenosis who underwent CEA was carefully followed on the basis of possible laryngeal and/or cranial nerve involvement. An ENT examination was carried out preoperatively (phase I) and at different times [3 (phase II) and 15 days (phase IIIa)] after surgery; in addition, patients with persisting neurological lesions were also checked 60 days after surgery (phase IIIb). RESULTS: In 59% of the patients, isolated or associated forms of deficit were found. Only 17.5% of these deficits did not appear to be transient, but rehabilitative procedures for voice or swallowing impairments were only needed in 9% of them.