The need for emergency surgical treatment in carotid-related stroke in evolution and crescendo transient ischemic attack.

OBJECTIVE: The purpose of this study was to examine the safety of emergency carotid endarterectomy (CEA) in patients with carotid stenosis and unstable neurological symptoms. METHODS: This prospective, single-center study involved patients with stroke in evolution (SIE) or fluctuating stroke or crescendo transient ischemic attack (cTIA) related to a carotid stenosis ≥ 50% who underwent emergency surgery. Preoperative workup included National Institute of Health Stroke Scale (NIHSS) neurological assessment on admission, immediately before surgery and at discharge, carotid duplex scan, brain contrast-enhanced head computed tomography (CT) or magnetic resonance imaging (MRI). End points were perioperative (30-day) neurological mortality, NIHSS score variation, and hemorrhagic or ischemic stroke recurrence. Patients were evaluated according to clinical presentation (SIE or cTIA), timing of surgery, and presence of brain infarction on neuroimaging. RESULTS: Between January 2005 and December 2009, 48 patients were submitted to emergency surgery. CEAs were performed from 1 to 24 hours from onset of symptoms (mean, 10.16 ± 7.75). Twenty-six patients presented an SIE with a worsening NIHSS score between admission and surgery, and 22 presented ≥ 3 cTIAs with a normal NIHSS score (= 0) immediately before surgery. An ischemic brain lesion was detected in four patients with SIE and eight patients with cTIA. All patients with cTIA presented a persistent NIHSS normal score before and after surgery. Twenty-five patients with SIE presented an NIHSS score improvement after surgery. Mean NIHSS score was 5.30 ± 2.81 before surgery and 0.54 ± 0.77 at discharge in the SIE group (P < .0001). One patient with SIE had a hemorrhagic transformation of an undetected brain ischemic lesion after surgery, with progressive neurological deterioration and death (2%). CONCLUSIONS: Due to the absence of randomized controlled trials of CEA for neurologically unstable patients, data currently available do not support a policy of emergency CEA in those patients. Our results suggest that a fast protocol, including CT scans and carotid duplex ultrasound scans in neurologically unstable patients, could help identify those that can be safely submitted to emergency CEA.

Urgent carotid endarterectomy to prevent recurrence and improve neurologic outcome in mild-to-moderate acute neurologic events.

OBJECTIVES: This study evaluated the safety and benefit of urgent carotid endarterectomy (CEA) in patients with carotid disease and an acute stable neurologic event. METHODS: The study involved patients with acute neurologic impairment, defined as ≥ 4 points on the National Institutes of Health Stroke Scale (NIHSS) evaluation related to a carotid stenosis ≥ 50% who underwent urgent CEA. Preoperative workup included neurologic assessment with the NIHSS on admission or immediately before surgery and at discharge, carotid duplex scanning, transcranial Doppler ultrasound imaging, and head computed tomography or magnetic resonance imaging. End points were perioperative (30-day) neurologic mortality, significant NIHSS score improvement or worsening (defined as a variation ≥ 4), and hemorrhagic or ischemic neurologic recurrence. Patients were evaluated according to their NIHSS score on admission (4-7 or ≥ 8), clinical and demographic characteristics, timing of surgery (before or after 6 hours), and presence of brain infarction on neuroimaging. RESULTS: Between January 2005 and December 2009, 62 CEAs were performed at a mean of 34.2 ± 50.2 hours (range, 2-280 hours) after the onset of symptoms. No neurologic mortality nor significant NIHSS score worsening was detected. The NIHSS score decreased in all but four patients, with no new ischemic lesions detected. The mean NIHSS score was 7.05 ± 3.41 on admission and 3.11 ± 3.62 at discharge in the entire group (P < .01). Patients with an NIHSS score of ≥ 8 on admission had a bigger score reduction than those with a lower NIHSS score (NIHSS 4-7; mean 4.95 ± 1.03 preoperatively vs 1.31 ± 1.7 postoperatively, NIHSS ≥ 8 10.32 ± 1.94 vs 4.03 ± 3.67; P < .001). CONCLUSIONS: In patients with acute neurologic event, a high NIHSS score does not contraindicate early surgery. To date, guidelines recommend treatment of symptomatic carotid stenosis ≤ 2 weeks from onset of symptoms to minimize the neurologic recurrence. Our results suggest that minimizing the time for intervention not only reduces the risk of recurrence but can also improve neurologic outcome.

Comparative study on carotid revascularization (endarterectomy vs stenting) using markers of cellular brain injury, neuropsychometric tests, and diffusion-weighted magnetic resonance imaging.

OBJECTIVE: Subclinical alterations of cerebral function can occur during or after carotid revascularization and can be detected by a variety of standard tests. This comparative study assessed the relationship among serum levels for two biochemical markers of cerebral injury, postoperative diffusion-weighted magnetic resonance imaging (DW-MRI), and neuropsychometric testing in patients undergoing carotid endarterectomy (CEA) or carotid artery stenting (CAS) for high-grade asymptomatic carotid stenosis. METHODS: Forty-three consecutive asymptomatic patients underwent carotid revascularization by endarterectomy (CEA, 20) or stenting (CAS, 23). They were evaluated with DW-MRI and the Mini-Mental State Examination (MMSE) test preoperatively and 5 points (P = .001). Analysis of S100beta and NSE levels showed a significant increase at 24 hours in CAS patients compared with CEA patients (P = .02). The MMSE score at 6 months showed a nonsignificant increase vs the postoperative score in both groups. CONCLUSIONS: Biochemical markers measurements of brain damage combined with neuropsychometric tests and DW-MRI can be used to evaluate silent injuries after CAS. The mechanisms of rise in S100beta and NSE levels at 24 hours after CAS may be due to increased perioperative microembolization rather than to hypoperfusion. Further studies are required to assess the clinical significance of those tests in carotid revascularization.

Chronological changes in morphometry and histology in the rabbit vascular wall after external radiation for the prevention of intimal hyperplasia.

BACKGROUND: Although ionizing radiation has been proposed for the prevention of intimal hyperplasia in coronary and peripheral arteries, information is lacking on how irradiation affects arterial histology and neointimal smooth-muscle cell proliferation-the hallmark of restenosis. We chronologically investigated early histological changes and quantitative changes in arterial wall cell proliferation after arterial injury followed by external radiation for the prevention of intimal hyperplasia in rabbits. MATERIALS AND METHODS: The aorta was experimentally injured in 26 rabbits who were then assigned to two groups: irradiation with 20 Gy and a control group with no irradiation. The aorta was resected for morphometric and histological studies at 3, 7, 15, 30, and 45 days after experimental injury. RESULTS: Intimal thickness was reduced and the intima/media ratio was significantly lower in irradiated groups than in control rabbits. In the irradiated group histological examination showed delayed neointimal proliferation with an intact endothelium. In the 20-Gy irradiated group the vascular media at 7 days contained necrotic areas and delayed fibrosis with calcifications. There was no statistical difference between the number of proliferating cells in the irradiated groups and the control group. Proliferating cells reached maximum numbers later in irradiated groups than in control rabbits (45 days versus 3 days). CONCLUSION: After arterial injury, external irradiation at 20 Gy effectively reduced aortic neointimal thickening. Irradiation-induced histological changes include recasting with rapid necrosis and delayed fibrosis. Radiation-induced parietal recasting with necrosis, fibrosis, and calcifications might worsen in time. Although irradiation after arterial injury leaves proliferative smooth-muscle cells within the arterial wall quantitatively unchanged in the early days after the procedure, it then induces a delayed reaction (observed over 45 days in our study). Whether neointimal hyperplasia is merely delayed or will ultimately develop causing restenosis awaits confirmation from experimental and clinical studies with a long-term follow-up.

Aortoiliac stent graft infection: current problems and management.

Aortic stent graft infection is uncommon. Most cases have been described anecdotaly in single-case reports. After observing one case in our experience, we decided to review the literature and contact centers performing endovascular aortic repair to determine the frequency, risk factors, and current treatment of stent graft infection. The literature was reviewed and the authors of identified articles were contacted for further information. In addition, 40 centers specializing in endovascular treatment were contacted by means a dedicated questionnaire. A total of 65 aortic stent graft infections were identified, including 43 reported cases and 22 previously unpublished cases that were observed at specialized centers. Stent grafts were implanted in the aorta in 50 cases and in the iliac artery in 15 cases. The frequency of infection was 0.43%. The gender ratio was 4:1 (M:F). Twenty-three percent of patients had immunodeficiency factors. Placement was performed in an interventional radiology suite in 62.5% of cases and in a sterile operating theater in 37.5%. Also, 35.5% of patients underwent other vascular procedures during the course of study and 29.2% stent grafts benefited from adjuvant endovascular procedures. Infection was classified as low grade in 35.4% of patients and high grade in 64.6%. Thirty-one percent of infections were associated with aortoenteric fistula. The offending microorganism was Staphylococcus aureus in 54.5% of cases. Treatment was conservative in 18% of cases and surgical in 82%. Surgical treatment consisted of stent graft removal followed by either extraanatomical bypass (59.5%) or in situ prosthetic reconstruction (40.5%). Mortality was 18% overall, 36.4% after conservative treatment and 14% after surgical treatment ( p = 0.083). Mortality was 16% after surgical treatment with extraanatomical bypass vs. 5.8% surgical treatment with in situ reconstruction. From these results we conclude that stent graft infection is an uncommon occurrence associated with poorly defined risk factors. Surgical treatment with complete excision of the infected stent graft followed by in situ reconstruction provides the best outcome. Establishment of a multicenter register to record such complications is needed to confirm the findings of this study.

Morphometric and histological changes in the vascular wall after external radiation for the prevention of intimal hyperplasia.

BACKGROUND: Recent reports describe spontaneous dissections and aneurysms after coronary and peripheral artery irradiation for the prevention of intimal hyperplasia. We investigated histological changes and the vasomotor reaction in the vascular wall after external radiation for the prevention of intimal hyperplasia in rabbits. MATERIALS AND METHODS: The aorta was experimentally injured in 34 rabbits who were then assigned to one of three groups: irradiation with 20 Gy; with 25 Gy; and a control group with no irradiation. Before the arterial injury and 45 days later, vasomotor function was assessed with an intravascular ultrasound catheter. The aorta was resected for morphometric and histological studies. RESULTS: After injury and irradiation, vasomotor responses were significantly lower in the two irradiated groups (P < 0.05). Intimal thickness and the intima/media ratio were significantly lower in irradiated groups. In the irradiated group histological examination showed reduced intimal proliferation with an intact endothelium. In the 20-Gy irradiated group the vascular media contained necrotic areas, and in the 25-Gy irradiated group, severe fibrosis. CONCLUSION: After arterial injury, external irradiation at 20 and 25 Gy effectively reduces aortic intimal and medial thickening. Histological changes include recasting with necrosis and fibrosis causing a decreased vasomotor response. Further investigations are needed to confirm medial necrosis and replacement with fibrosis. Because the irradiation doses in this study match those currently used and also recommended for experimental and clinical use, if confirmed in humans parietal recasting might possibly explain the reported spontaneous dissections and aneurysm formation after irradiation.

Matrix metalloproteinase 9 activity in patients before and after endovascular or surgical repair of abdominal aortic aneurysms.

The objective of this prospective study was to assess matrix metalloproteinase 9 (MMP-9) activity in patients undergoing open surgery or endovascular repair of abdominal aortic aneurysms (AAAs), comparing changes in plasma levels in the two groups. We studied 12 patients after conventional open surgery and 9 patients after endovascular aneurysm repair. MMP-9 was assayed in plasma at baseline and 1 week and 1 month thereafter. Preoperative MMP-9 levels were similar in the two groups (41.7 +/- 19.1 vs 44.4 +/- 24.6 ng/mL; p = not significant). Assessment 1 week later showed that MMP levels in both repair groups had increased. In the open surgery group, they increased significantly (59.7 +/- 16.8 ng/mL; p < .05) but not in the endovascular group (49.3 +/- 32.4 ng/mL). One month later, MMP-9 levels decreased in both groups but not significantly (to 32.6 +/- 24.6 ng/mL for open surgery repair and to 34.7 +/- 23.5 ng/mL for endovascular repair). At 1 month after repair, MMP-9 levels decreased significantly only in smokers, whereas in nonsmokers, they did not (from 46.9 +/- 22.1 to 31.7 +/- 21.5 ng/mL in smokers [p < .05] vs from 34.7 +/- 17.4 to 37.1 +/- 28.9 ng/mL in nonsmokers). This study confirms that enzyme secretion changes during the postoperative course. The differing patterns of MMP-9 expression prevent us from reaching definitive conclusions about the use of MMP-9 as a marker during early postprocedural follow-up. An important matter to clarify is the role of MMP-9 in long-term follow-up, especially after endovascular AAA repairs.

Endovascular graft infection: preliminary results of an international enquiry.

PURPOSE: To investigate the frequency of aortoiliac endovascular graft infections and seek the main factors influencing their development. METHODS: To augment personal experience (1 case), a questionnaire was sent to 40 international centers of vascular and endovascular surgery. The literature was also reviewed to collect data on infections developing in endovascular grafts. RESULTS: The survey (85% response rate) and literature review identified 62 cases of infected endovascular grafts (0.4% frequency of endograft infection). In 22 (35%) patients, the infection manifested initially with vague symptoms only, but 41 (65%) patients eventually presented with abdominal abscess, groin fistula, and septic embolization. Common bacteria, such as Staphylococcus aureus, were identified as the cause of most infections (54.5%). The majority (49, 79%) of the 62 patients were treated surgically; 11 (17.7%) patients received conservative therapy (no therapeutic data in 2 patients). Overall mortality was 27.4% (17/62), and operative mortality was 16.3% (8/49). Conservative treatment led to a mortality rate of 36.4% (4/11). The mean follow-up for all patients was 47.8 weeks. Possible factors influencing the development of an infection were secondary adjunctive procedures, immunosuppression, treatment of false aneurysms, and infected central lines. CONCLUSIONS: Infected endovascular grafts are an urgent problem that has been heretofore underestimated and will probably increase as follow-up lengthens. New techniques should be sought to expedite the diagnosis, and an international registry should be set up to provide validated data.

Contrast-enhanced ultrasound imaging for aortic stent-graft surveillance.

PURPOSE: To compare unenhanced and enhanced ultrasound imaging to computed tomographic angiography (CTA) or magnetic resonance angiography (MRA) for surveillance of aortic endografts. METHODS: Thirty consecutive patients (29 men; mean age 69 years, range 50-82) who underwent endovascular aortic aneurysm repair agreed to participate in a follow-up program. Patients underwent CTA (26/30) or MRA (4/30), plain abdominal radiography, and unenhanced and enhanced ultrasound examinations at 3, 12, and 24 months to evaluate aneurysm diameter, endoleaks, and graft patency. The accuracy of ultrasound was compared with CTA or MRA as the reference standards. RESULTS: Twenty-six patients reached the 24-month assessment (mean follow-up 30 months, range 6-60). All endoleaks detected by CTA or MRA were confirmed by enhanced ultrasound; the aneurysm diameter in these patients remained unchanged or increased. In patients without endoleaks on any imaging method, the sac diameter remained unchanged or decreased. Endoleaks disclosed by enhanced ultrasound alone, all type II, numbered 16 at 3 months, 6 at 12 months, and 3 at 24 months. In this group, the aneurysm diameter remained unchanged or increased. Enhanced ultrasound yielded 100% sensitivity in detecting endoleaks, but compared with CTA and MRA, all endoleaks detected by enhanced ultrasound alone were false positives (mean specificity 65%). Nevertheless, because changes in the postoperative aneurysm diameter were similar in patients with endoleaks detectable on CTA/MRA and on enhanced ultrasound ("true positives") and in those with endoleaks detectable only on enhanced ultrasound ("false positives"), some endoleaks were possibly "true positive" results. CONCLUSIONS: Enhanced ultrasound is a useful method in the long-term surveillance of endovascular aortic aneurysm repairs, possibly in association with CTA or MRA. Enhanced ultrasound also seems able to identify endoleaks missed by other imaging techniques, but this conclusion awaits further investigation.

Color Doppler ultrasound guidance during renal angioplasty and stenting.

PURPOSE: To investigate whether an imaging technique combining color Doppler ultrasonography and selective renal artery digital subtraction angiography reduces contrast requirements in patients with progressive renal insufficiency undergoing renal artery angioplasty and stenting. METHODS: Eight patients (5 men; mean age 58 years) with renal artery stenosis and renal insufficiency underwent percutaneous transluminal angioplasty and stenting under color Doppler ultrasound guidance. RESULTS: Color Doppler ultrasound imaging yielded the information necessary for verifying catheter position, stent placement and expansion, and hemodynamics after revascularization. The combined imaging technique considerably reduced contrast requirements to only 10 mL in each case. No worsening of renal function was seen in any patient. CONCLUSIONS: The combined imaging procedure uses low doses of contrast agent and is especially suited to patients with renal dysfunction undergoing percutaneous renal revascularization.

Diagnosis of vascular graft infections with antibodies against staphylococcal slime antigens.

Late-onset infections of synthetic vascular grafts (LO-SVGIs) are generally caused by staphylococci that produce a slime polysaccharide and grow as a biofilm on the graft surface. We developed an ELISA to detect serum antibodies against staphylococcal slime polysaccharide antigens (SSPA). Patients with an ongoing staphylococcal LO-SVGI had greater titres of IgM antibodies against SSPA than did patients in other groups. Antibody titres of 0.40 ELISA units (EU) or more, or 0.35 EU or more detected 97% and 100% of staphylococcal LO-SVGIs, respectively, 0% and 2% titre/unit false-positive results. Our findings suggest that such an ELISA represents a sensitive, specific, and non-invasive diagnostic test for staphylococcal LO-SVGIs.