Faculty Bibliography

Recent reviews of device-specific complications using neuroprotection have addressed technical difficulties during delivery as well as adverse outcomes, intraoperative and 30-day. Little has been written, however, regarding the relevance of filter occlusion during the carotid stent procedure. A retrospective review was conducted of patients undergoing carotid artery stent procedures using a variety of neuroprotection devices from 2003 to 2007. Prospective databases from two institutions were examined for incidence and management of filter occlusions during procedures as well as adverse neurological events (intraoperative and 30-day) associated with filter occlusion. There were 283 carotid artery stent procedures performed on 256 patients (163 male, 93 female): 177 (62.5%) arteries were asymptomatic and 106 were symptomatic. Neurological adverse events occurred in six patients (2.1%); three of these resolved completely at 72 hr. Neuroprotection was used in 95% of all patients, and filters were used in 221 stent procedures: Boston Scientific Filter Wire (n = 81), Guidant Accunet (n = 100), Angioguard (n = 17), and Abbot Emboshield (n = 23). Filter occlusion occurred in 11 patients (4.9%) in whom this form of neuroprotection was employed: Angioguard (n = 5), Accunet (n = 2), Emboshield (n = 2), and EPI Filter wire (n = 2). Two of the 11 patients with filter occlusions suffered a neurological event. There was no correlation between filter occlusion and gender, symptoms, stent, or filter type (p > 0.05). Filter occlusion was managed with export catheter-directed aspiration in seven patients and with prompt filter retrieval in five patients. Filter occlusion is an infrequent event that does not appear to be filter-specific and can be managed successfully by catheter-directed aspiration or filter retrieval. The majority of patients with filter occlusion do not suffer from atheroemboli as a result of this occlusion

Carotid artery interventions can be associated with adverse hemodynamic changes, including bradycardia and hypotension. These hemodynamic changes are believed to be caused by direct stimulation of the carotid sinus baroreceptors, mimicking normal physiological response to rises in blood pressure. During open carotid surgery, these hemodynamic changes can be controlled by direct injection of medications that block fast voltage gated sodium channels in the neuron cell membrane, thus preventing depolarization of the presynaptic neuron in the carotid sinus. This form of control is difficult or impossible during percutaneous carotid interventions because direct access to the carotid artery and carotid sinus is not available. This discussion focuses on the cause, effects, and possible treatments for the hemodynamic changes associated with carotid artery stenting procedures

PURPOSE: Clinical decision making for carotid surgery depends largely upon stenosis grade. While digital subtraction angiography remains the gold standard for stenosis grading, many physicians use less invasive modalities. The purpose of this study was to compare the results of multidimensional Computed tomography (CTA) with ultrasound (US) grading and peak flow velocity (PSV). METHODS: 37 stenosed carotid arteries were studied retrospectively in 36 consecutive patients. US grading and PSV were compared to multidimensional CTA analysis (diameter, area and volumetric measurements), performed by a medical software company. Calculations of stenosis percentage on CTA were made using the NASCET and ECST methodology. Diameter measurements were also performed by a neuroradiologist. RESULTS: All CTA diameter, area and volume measurements had only modest correlation with PSV (r<0.5) and ultrasound grading (p<0.5). There was concordant classification of stenosis grades in only 40-60% of cases. CTA diameter, area and volume measurements had good correlation (0.69<r<0.87) with one another using ECST methodology. Using NASCET methodology on CTA, correlation between diameter and area was insignificant (r=0.32). CTA volumetric analysis with the NASCET method yielded 27 negative stenosis grades. Repeatability coefficient for selecting the normal distal ICA 20 mm more distally was 20% for diameter and 43% for area. CTA diameter interobserver repeatability coefficients were 22.9% (NASCET) and 17.8% (ECST) and 0.7 mm (lumen) and 1.9 mm (vessel). CONCLUSIONS: All CTA measurements showed moderate correlation with both ultrasound grading and PSV. Selection of the level of the normal distal ICA influences the NASCET calculations and can produce discrepant stenosis grades. Multidimensional CTA analysis seems to have no additional value for stenosis grading, but provides other useful anatomic information

BACKGROUND: In previous studies, we found that approximately 25% of patients having carotid endarterectomy with general anesthesia (CEA general) develop cognitive dysfunction compared with a surgical control Group 1 day and 1 mo after surgery. In this study, we tested the hypothesis that patients having CEA with regional anesthesia (CEA regional) will develop significant cognitive dysfunction 1 day after surgery compared with a control group of patients receiving sedation 1 day after surgery. We did not study persistence of dysfunction. METHODS: To test this hypothesis, we enrolled 60 patients in a prospective study. CEA regional was performed with superficial and deep cervical plexus blocks in 41 patients. The control group consisted of 19 patients having coronary angiography or coronary artery stenting performed with sedation. A control group is necessary to account for the 'practice effect' associated with repeated cognitive testing. The patients from the CEA regional group were enrolled at New York Medical Center and the control group at Columbia-Presbyterian Medical Center. The cognitive performance of all patients was evaluated using a previously validated battery of neuropsychometric tests. Differences in performance, 1 day after compared with before surgery, were evaluated by both event-rate and group-rate analyses. RESULTS: On postoperative day 1, 24.4% of patients undergoing CEA regional had significant cognitive dysfunction, where 'significant' was defined as a total deficit score > or =2 SD worse than the mean performance in the control group. CONCLUSIONS: Patients undergoing CEA regional had an incidence of cognitive dysfunction which was not different than patients having CEA general as previously published and compared with a contemporaneously enrolled group

We present a case of Viabahn (W. L. Gore & Associates, Flagstaff, Ariz) collapse during popliteal artery aneurysm treatment. An elderly man with severe comorbidities presented with a 34-mm popliteal artery aneurysm. Proximal and distal landing sites of 11 and 9 mm, respectively, demonstrated by preoperative computed tomography angiography were confirmed by intraoperative angiography. After Viabahn deployment, angiography revealed a filling defect in the distal popliteal graft with poor flow. Balloon dilatation failed. A femoropopliteal bypass with aneurysm ligation was performed. Transection of the distal popliteal vessel demonstrated complete infolding. Our choice of grafts represented 15% to 18% proximal and distal oversizing. Focal areas of relative vessel narrowing may lead to incomplete graft unfolding and graft failure

Determination of degree of carotid artery stenosis is of critical importance when deciding whether a patient warrants surgical intervention. While angiography is still considered by some to be the true reference standard for imaging the internal carotid artery (ICA), physicians rely most commonly on duplex imaging when planning for endarterectomy. It is noninvasive, safe, and overall reliable for grading stenosis but is nevertheless user-dependent and can be limited in cases of severe calcification. Moreover, a lack of consensus for duplex criteria can be confounding. In recent years, magnetic resonance angiography (MRA) and computed tomographic angiography (CTA) have assumed a more prominent role in the preoperative planning for treatment of carotid stenosis. Improved resolution and faster acquisition times for both of these imaging modalities have allowed for accurate depictions of degree of stenosis, as well as plaque characterization. CTA and MRA may have special relevance in the era of carotid stenting, since challenging arch anatomy and identification of a high-risk vulnerable plaque may be useful when deciding whether to perform a stent procedure or endarterectomy

Durable vascular access for hemodialysis remains a critical issue in end-stage renal disease patients. Creation of an autogenous arteriovenous (AV) fistula in the most distal location of the nondominant extremity is the preferred technique and provides superior patency over an AV graft. Others have shown that regional anesthesia in the form of axillary block results in the dilatation of the native veins and allows for their increased utilization in creating AV fistulae. We report on 26 patients undergoing creation of a vascular access for hemodialysis. Regional anesthesia consisting of axillary nerve block was used in all cases. All surgical plans with regard to the site and type of access were made based on the physical exam and ultrasound vein measurements taken prior to surgery. On the day of surgery patients were reevaluated with venous ultrasound using tourniquet before and after administration of the regional block. The previously determined operative plan either remained unchanged or was modified depending on the venous dilatation noted after administration of regional block. Among 26 patients, average vein diameter increased from 0.29 +/- 0.12 cm to 0.34 +/- 0.11 cm (P = 0.008). Twenty-one of 26 patients had no modification in operative plan (group 1). Five had some modification of the original operative plan (group 2): AV graft to a brachial vein transposition (n = 2), AV graft to a Cimino fistula (n = 2), and brachiocephalic to a Cimino (n = 1). The average follow-up for all patients was 82.6 +/- 75.6 days and did not differ between the groups. There was one failure in a patient from group 1, and there was no significant difference in the patency rate between study groups (P = 0.29). Following regional nerve block, operative plans in patients undergoing AV access surgery were modified in 29.4% of patients undergoing creation of an AV access for hemodialysis; either from graft to fistula creation or from the proximal to more distal fistula site. The routine use of regional anesthesia as well as intraoperative ultrasound during AV access surgery can lead to improved site selection and increased opportunity for AV fistula creation

Ischemic complications after endovascular abdominal aortic aneurysm repair (EVAR) are well-recognized and have been reported to be as high as 9%. The goal of our study was to examine the incidence, management, and outcome of ischemic complications at our institution after EVAR and to compare complications according to graft type and time period. This is a retrospective review of all EVARs performed at our institution from 1993 through 2005 (n = 430). EVAR was performed in asymptomatic patients in most cases. Follow-up consisted of a computed tomography scan and office visit at 1, 6, and 12 months and yearly thereafter. Ischemic complications after EVAR have decreased significantly with the advent of lower-profile devices with easier delivery systems and supported limbs. Simultaneous coil embolization of internal iliac artery at the time of EVAR implant does not appear to increase the risk of pelvic or lower-extremity ischemia, can be done safely, and does not need to be staged

Left renal vein ligation has been used as a technical aid to gain exposure to the perirenal aorta and to control bleeding in abdominal aortic operations. Left renal vein ligation is considered to be well tolerated in patients with 2 functioning kidneys, but has rarely been described in the setting of concomitant right nephrectomy and presents a management challenge. Some reports suggest recovery of renal function may be possible after left renal vein ligation during right nephrectomy, but other suggest that a delay in revascularizing the left renal venous drainage may result in irreversible nephropathy. This article reports the inadvertent division of the left renal vein during right nephrectomy. Renal failure ensued postoperatively. The left renal vein was reconstructed, and renal function was recovered. The inability to reliably predict which patients will have adverse outcome after left renal vein ligation in the setting of a right nephrectomy may necessitate preemptive intervention