Functional MR imaging in patients with carotid artery stenosis before and after revascularization.

BACKGROUND AND PURPOSE: Significant extracranial stenosis of the ICA is a known risk factor for future stroke and it has been shown that revascularization reduces the risk of future stroke. We applied BOLD fMRI in patients with carotid artery stenosis before and after CEA. Our purpose was to determine whether fMRI is able to demonstrate impaired CVR and to identify patient parameters that are associated with postoperative changes of cerebral hemodynamics. MATERIALS AND METHODS: Nineteen consecutive patients with symptomatic (n = 13) and asymptomatic (n = 6) stenosis of the ICA were prospectively recruited (male/female ratio = 16:3; age, 69 ± 8,1 years). fMRI using a simple bilateral motor task was performed immediately before and after CEA. RESULTS: Mean BOLD MSC was significantly increased postoperatively (MSC, 0.13 ± 0.66; P = 0.0002). Patients with a stenosis of <80% demonstrated an increase in MSC (MSC, 0.32 ± 0.59; P ≤ .0001). Patients with previous ischemic stroke showed a larger MSC than patients with TIAs (stroke: MSC, 0.55 ± 0.65; P ≤ .0001; TIA: MSC, 0.05 ± 0.26; P = 0.054). Patients older than 70 years had a significantly larger MSC following surgery (≤70 years: MSC, -0.01 ± 0.39; P = .429; >70 years: MSC, 0.29 ± 0.48; P ≤ .0001). CONCLUSIONS: BOLD fMRI can demonstrate changes in cerebral hemodynamics before and after CEA, indicative of an ameliorated CVR. This response is dependent on the age of the patient, the degree of preoperative stenosis, and the patient's symptoms.

Early control of distal internal carotid artery during carotid endarterectomy: does it reduce cerebral microemboli?

AIM: According to the results of the large trials on carotid endarterectomy (CEA), this type of surgery is only warranted if perioperative mortality and morbidity are kept considerably low. Less attention has been paid to methods of cerebral protection during CEA, although intraoperative transcranial Doppler (TCD) can visualise intracerebral microemboli (MES) during routine carotid dissection, although MES occur throughout the CEA, only those during dissection are related to neurological outcome. Prevention of MES by means of early control of the distal internal carotid artery dislodging from the carotid artery plaque during dissection is very likely the mechanism behind an eventual benefit from this approach. Hence, the amount of MES might serve as a surrogate parameter for the risk of periprocedural neurological events. So, the aim of the present study was to evaluate whether early control of the distal carotid artery during CEA is capable of reducing the number of MES by means of a prospective randomised trial. METHODS: Twenty-eight patients (29 procedures) could be prospectively included in our study. Before surgery we randomly assigned the patients to two groups: group A (N.=12): CEA by means of early control of the distal internal carotid artery; group B (N.=17): CEA with dissection of the total carotid bifurcation before clamping the arteries. Periprocedurally, we continuously monitored the cerebral blood flow in the ipsilateral middle cerebral artery by means of TCD. Pre- and postoperative morbidity were independently verified by a neurologist <2 days before and not later than five days after the procedure. Values of microembolic signs during dissection were summarised with arithmetic means and standard deviations. For further analysis non parametric Wilcoxon test was performed between both methods. P-values <0.05 were considered as statistically significant. Wilcoxon test was performed to compare both methods concerning clamp- and procedure times. RESULTS: We performed EEA 26 times, in three patients a longitudinal arteriotomy with endarterectomy and patchplasty was performed, in one of these patients a shunt was necessary. In 12 twelve patients MES occurred during the dissection before clamping. Eight of these patients belonged to group B and four patients to group A. The mean number of MES during dissection for group A was 2.4 (SD 4.6; 5-15) and for group B 3.9 (SD 7.1; 2-28). There is no statistically significant difference in the Wilcoxon-test; P=0.4375. There was no patient showing reperfusion syndrom or clinical signs of a new cerebral infarction or any other neurological deficit. There were no other major complications like myocardial infarction or death as well as no minor complications like periphereal nerve lesions, bleeding or wound healing disturbance. CONCLUSION: In this prospective, randomised trial early control of the distal internal carotid artery did not reduce the occurrence of MES during dissection of the carotid bifurcation. Also, the total number of MES throughout the procedure and postoperatively was comparable between both groups. The procedure related times as well as the clinical outcome did not differ significantly. Thus, early control of the distal internal carotid artery has got no advantage but also no disadvantage as compared to the traditional CEA technique. However, a limitation of the study is the small number of patients included.

Case-control comparison of profundaplasty and femoropopliteal supragenicular bypass for peripheral arterial disease.

BACKGROUND: The aim of this study was to compare preoperative and postoperative findings, and clinical progress in patients with peripheral arterial occlusive disease undergoing femoropopliteal supragenicular bypass or profundaplasty in a case-control study. METHODS: Between January 2001 and June 2004, 171 patients with occlusion of the superficial femoral artery underwent surgery. A retrospective analysis of 28 matched patient pairs was performed. Endpoints were bypass occlusion, surgical revision, amputation and death. Mean length of follow-up was 36 months. RESULTS: At 3 years after surgery there was no statistically significant difference in outcome between femoropopliteal bypass surgery and profundaplasty. There was a trend towards improved results in patients who had bypass surgery for critical leg ischaemia. Preoperative patency of the crural outflow arteries was an independent prognostic factor in multivariable analysis. CONCLUSION: There were no significant outcome differences between supragenicular bypass surgery or profundaplasty in patients who had surgery for intermittent claudication or ischaemic rest pain. Patients with a single patent tibial artery and gangrene or ulceration appeared to benefit more from bypass surgery.

Carotid plaque analysis: comparison of dual-source computed tomography (CT) findings and histopathological correlation.

PURPOSE: Plaque morphology is an important predictor of stroke risk and may also be a predictor of postoperative outcome after carotid endarterectomy (CEA). Thus, the purpose of our study was to evaluate the findings of preoperative dual-source computed tomography (DSCT) of carotid plaque morphology and correlate these findings with histopathological findings. MATERIAL AND METHODS: Thirty patients undergoing CEA due to neurological events and high-grade carotid artery stenosis were evaluated with DSCT for degree of stenosis following the North American Symptomatic Carotid Endarterectomy Trial (NASCET) criteria and for non-invasive plaque morphology prior to CEA. CT protocol was as follows (SOMATOM Definition, Siemens Medical Solutions, Forchheim, Germany): A dual-energy protocol was used with tube A (140 kV, 55 mA) and tube B (80 kV, 230 mA) with 2 x 64 x 0.6-mm collimation, pitch 0.65 and rotation time of 0.33 s. Histopathological work-up was performed on the surgically retrieved tissues. The findings from DSCT and histopathology were compared with respect to image quality and plaque composition (fatty plaque, mixed plaque and calcified plaque), were correlated with histological specimens and classified according to the American Heart Association (AHA) classification of atherosclerotic plaque. Pearson correlation and kappa statistics were performed. RESULTS: The image quality of DSCT was rated as 'excellent' in all the examinations. The mean degree of stenosis was quantified as 82%. The sensitivity of DSCT for the detection of calcification was 100% (standard deviation (SD) 0%, confidence interval (CI): 99-100). While the sensitivity for the detection of mixed plaques was 89% (SD 12%, CI: 79-98), it was 85% (SD 10%, CI: 76-92) for the detection of low-density fatty plaques. The mean degree of agreement was k=0.81. CONCLUSION: DSCT angiography of the carotid arteries is feasible and the evaluation of carotid plaque composition allows non-invasive assessment of different plaque components. This may have an impact on the non-invasive differentiation of vulnerable plaques.

The role of procalcitonin as predictor for neurological deficits after carotid endarterectomy.

AIM: Outcome of carotid endarterectomy (CEA) is defined by mortality rate as well as the neurological outcome due to cerebral ischemia. Thus the aim of this study was to evaluate the role of the acute phase protein procalcitonin (PCT) as a predictor for neurological deficits after carotid endarterectomy. METHODS: Fifty-five patients with high grade stenosis of the internal carotid artery and interdisciplinary consensus for endarterectomy were followed. Neurological examination was performed before and after the procedure to analyze perioperative neurological deficits. Blood samples were obtained before and after CEA and procalcitonin was analyzed in 55 consecutive patients (65.5% symptomatic/34.5% asymptomatic). RESULTS: No perioperative or in-hospital death was observed. Major complications did not occur, two patients suffered from bleeding requiring surgical intervention and one patient had a temporary peripheral facial nerve lesion. Postoperative neurological examination revealed no new deficit, there was no significant change of PCT (level pre- and post-CEA (the mean preoperative PCT was 0.25 ng/mL [SD 0.78, min 0.1, max 4.3]; the mean postoperative PCT was 0.11 ng/mL [SD 0.06, min 0.1, max 0.5]). There was no association found between perioperative neurological deficit and PCT. CONCLUSIONS: The present study demonstrates that there is still not sufficient evidence to recommend PCT measurement as a predictor for perioperative neurological deficit during CEA.

Thoracoabdominal aortic aneurysm repair in patients with marfan syndrome.

OBJECTIVE: We assessed the surgical outcome of descending thoracic aortic aneurysm repair (DTAA) and thoracoabdominal aortic aneurym (TAAA) repair in patients with Marfan syndrome. METHODS: During a six year period, 206 patients underwent DTAA and TAAA repair. In 22 patients, Marfan syndrome was confirmed. The median age was 40 years with a range between 18 and 57 years. The extend of the aneurysms included 6 DTAA (1 with total arch, 2 with distal hemi-arch), 11 type II TAAA (2 with total arch, 3 with distal hemi-arch), 4 type III and one type IV TAAA. All patients suffered from previous type A (n=6) or type B (n=16) aortic dissection and 15 already underwent aortic procedures like Bentall (n=7) and ascending aortic replacement (n=8). All patients were operated on according to the standard protocol with cerebrospinal fluid drainage, distal aortic and selective organ perfusion and monitoring motor evoked potentials. In patients undergoing simultaneous arch replacement (via left thoracotomy), transcranial Doppler and EEG assessed cerebral physiology during antegrade brain perfusion. In four patients circulatory arrest under moderate hypothermia was required. RESULTS: In-hospital mortality did not occur. Major postoperative complications like paraplegia, renal failure, stroke and myocardial infarction were not encountered. Mean pre-operative creatinine level was 125mmol/L, which peaked to a mean maximal level of 130 and returned to 92mmol/L at discharge. Median intubation time was 1.5 days (range 0.33-30 days). Other complications included bleeding requiring surgical intervention (n=1), arrhythmia (n=2), pneumonia (n=2) and respiratory distress syndrome (n=1). At a median follow-up of 38 months all patients were alive. Using CT surveillance, new or false aneurysms were not detected, except in one patient who developed a visceral patch aneurysm six years after open type II repair. CONCLUSION: Surgical repair of descending and thoracoabdominal aortic aneurysms provides excellent short- and mid-term results in patients with Marfan syndrome. In this series, a surgical protocol with cerebrospinal fluid drainage, distal aortic and selective organ perfusion and monitoring motor evoked potentials resulted in low morbidity and absent mortality. These outcomes of open surgery should be considered when discussing endovascular aneurysm repair in Marfan patients.

Differences of venous thromboembolic risks in vascular general and trauma surgery patients.

AIM: Venous thromboembolism (VTE) is a common complication in patients undergoing surgery. The risk for VTE is determined by the combination of individual predisposing factors and features of the specific type of surgery. Although the knowledge about VTE has increased enormously during the last years VTE-prophylaxis is still inadequate. The goals of our study were to assess the correctness of the adjusted pharmacological prophylaxis, and the difference of the VTE-risks in the different surgical departments. METHODS: During a three months period, 451 patients were prospective included. These patients were admitted to the Departments of Vascular and General Surgery and of Traumatology of our hospital. Based on the modified Hertfelder's VTE-risk-assessment model, we scored the patients and categorized them into 4 groups: low, moderate, high and very high risk for VTE. We enrolled every admitted patient taking their medical history and reviewing medical documents. RESULTS: The mean cumulative risk value for VTE-risk was 3.68 (median 3.5, minimum: 0, maximum: 13 and standard deviation: 2.206), whereas 20.2% of our patients had a low, 27.2% middle, 21.7% high and 30.9% very high risk. The patients with vascular procedures had significantly higher mean value (5.03, SD 2.2) than the patients with general operations (3.6, SD 2.2) and those who underwent traumatology (3.06, SD 1,8) (P value <0.001). The majority of patients (n=356), (78.9%) received VTE-prophylaxis with low dose of low molecular weight heparin (LMWH). Of the remaining patients, 40 (8.9%) received therapeutic dose and 55 (12.2%) received none VTE-prophylaxis. CONCLUSION: The VTE-risk for surgical patients remains high, despite all efforts for prophylaxis. The main reason may be that risk-assessment is time consuming and not standardized. We demonstrated that VTE-risk for patients in vascular surgery is significantly higher than the VTE-risk for patients in general and trauma surgery. We also showed that the VTE-risk in some patients was underestimated and prophylaxis was inadequate. Therefore, it is recommended to emphasize more on short risk-assessment, adequate prophylaxis and optimal dosage in order to prevent deep venous thrombosis and embolism disease.

Surgical repair of thoracoabdominal aortic aneurysms.

Morbidity and mortality following thoracoabdominal aortic aneurysm (TAAA) repair are tremendous. Preoperative assessment is essential in detecting cardiac and pulmonary risk factors in order to reduce cardiopulmonary complications. Paraplegia and renal failure are main determinants of postoperative mortality and therefore gained substantial attention during the last decades. Left heart bypass, cerebrospinal fluid (CSF) drainage and epidural cooling have significantly reduced paraplegia rate, however, this dreadful event still occurs in up to 25% of patients undergoing type II repair. Renal failure has been partly prevented by means of retrograde aortic perfusion and cooling but renal failure still remains a significant problem. We have evaluated the effects of protective measures aiming for reduction of paraplegia and renal failure. Monitoring motor evoked potentials (MEPs) is an accurate technique to assess spinal cord integrity during TAAA repair, guiding surgical strategies to prevent paraplegia. Selective volume- and pressure controlled perfusion is a technique to continuously perfuse the kidneys during aortic cross clamping and subsequent circulatory exclusion In patients with atherosclerotic thoracoabdominal aortic aneurysms, blood supply to the spinal cord depends on a highly variable collateral system. In our experience, monitoring MEPs allowed detection of cord ischemia, guiding aggressive surgical strategies to restore spinal cord blood supply and reduce neurologic deficit: overall paraplegia rate was less than 3%. We believe that these protective measures should be included in the surgical protocol of TAAA repair, especially in type II cases. Renal and visceral ischemia can be reduced significantly by continuous perfusion during aortic cross clamping in TAAA repair. Not only sufficient volume flow but also adequate arterial pressure appears to be essential in maintaining renal function.Obviously, endovascular modalities have been successfully applied in TAAA patients, the majority of which as part of hybrid procedures. Technological innovation will eventually cause a shift from open to minimal invasive surgical repair. At present, however, open surgery is considered the gold standard for TAAA repair, especially in (relatively) young patients and patients suffering from Marfan's disease.

The coeliac aneurysm: a rare cause of abdominal pain.

Visceral artery aneurysms (VAA) represent 0.1-0.2% of all vascular aneurysms. For VAA's etiology, congenital or arteriosclerotic factors, media defects, infections, vasculitis and trauma are discussed. Ultrasound, CT scan and magnetic resonance imaging underline the diagnosis of VAA. The low perioperative morbidity and mortality and the excellent surgical longterm results justify the prophylactic therapy also from asymptomatic VAA because the mortality of ruptured VAA is close to 100%. The radiological interventional treatment is indicated for only selected patients whereas an advantage is not verified yet.