MRI plaque imaging reveals high-risk carotid plaques especially in diabetic patients irrespective of the degree of stenosis.

BACKGROUND: Plaque imaging based on magnetic resonance imaging (MRI) represents a new modality for risk assessment in atherosclerosis. It allows classification of carotid plaques in high-risk and low-risk lesion types (I-VIII). Type 2 diabetes mellitus (DM 2) represents a known risk factor for atherosclerosis, but its specific influence on plaque vulnerability is not fully understood. This study investigates whether MRI-plaque imaging can reveal differences in carotid plaque features of diabetic patients compared to nondiabetics. METHODS: 191 patients with moderate to high-grade carotid artery stenosis were enrolled after written informed consent was obtained. Each patient underwent MRI-plaque imaging using a 1.5-T scanner with phased-array carotid coils. The carotid plaques were classified as lesion types I-VIII according to the MRI-modified AHA criteria. For 36 patients histology data was available. RESULTS: Eleven patients were excluded because of insufficient MR-image quality. DM 2 was diagnosed in 51 patients (28.3%). Concordance between histology and MRI-classification was 91.7% (33/36) and showed a Cohen's kappa value of 0.81 with a 95% CI of 0.98-1.15. MRI-defined high-risk lesion types were overrepresented in diabetic patients (n = 29; 56.8%). Multiple logistic regression analysis revealed association between DM 2 and MRI-defined high-risk lesion types (OR 2.59; 95% CI [1.15-5.81]), independent of the degree of stenosis. CONCLUSION: DM 2 seems to represent a predictor for the development of vulnerable carotid plaques irrespective of the degree of stenosis and other risk factors. MRI-plaque imaging represents a new tool for risk stratification of diabetic patients.

Is serum pregnancy-associated plasma protein A really a potential marker of atherosclerotic carotid plaque stability?

OBJECTIVES: The search for markers predicting risk of plaque rupture in carotid atherosclerosis is still ongoing. Previous findings showed that pregnancy-associated plasma protein-A (PAPP-A) levels correlate with an adverse plaque morphology. However, the role of PAPP-A in plaque destabilisation is still uncertain. MATERIAL AND METHODS: Patients with carotid artery stenosis involved in the study were asymptomatic (n=29) and symptomatic (n=37). Carotid plaques were characterised by histology (n=33). Immunohistochemistry (n=17) was used to determine expression of PAPP-A and CD68 within the plaques. Serum levels of PAPP-A were measured by the enzyme-linked immunosorbent assay (ELISA). RESULTS: Circulating PAPP-A levels were significantly higher in patients with unstable versus stable plaques (0.10+/-0.06 vs. 0.07+/-0.04 microg ml(-1), p=0.047) and interestingly, in asymptomatic versus symptomatic patients (0.11+/-0.05 vs. 0.069+/-0.09 microg ml(-1), p=0.025). These differences remained statistically significant after adjustment for age, gender and degree of stenosis (p=0.050). PAPP-A expression in plaques correlated significantly with CD68 positive macrophages, cap-thickness and its serological values (r=+0.291, p<0.001, r=-0.639, p<0.001 and r=0.618, p<0.008, respectively). Furthermore, PAPP-A serum values demonstrated a significant positive predictive value of 68.8% for unstable plaques. CONCLUSION: Our present data confirmed the close relationship between expression of PAPP-A and plaque instability and furthermore correlated significantly with cap thickness. However, the question whether PAPP-A is a useful predictive marker of plaque instability remains unresolved.

PEPE II--a multicenter study with an end-point heparin-bonded expanded polytetrafluoroethylene vascular graft for above and below knee bypass surgery: determinants of patency.

AIM: The Propaten European Product Evaluation (PEPE II) study was a product evaluation intended to characterize the performance of the GORE PROPATEN vascular graft in above-knee (AK) and below-knee bypass (BK) surgery. METHODS: This prospective multicenter trial enrolled 142 patients with peripheral arterial disease. In 87 patients AK and in 52 patients BK bypasses (including 15 femorocrural) were implanted (67.6% males, 32.4% females). RESULTS: The one-year overall primary and secondary patency rates were 80% and 84.7%, respectively. Overall limb salvage rate at 12-months was 96.2%. The primary patency rate for AK bypasses was 82.7%, for BK femoro-popliteal bypasses 74.2% and for BK tibial-peroneal bypasses 79.4%. Secondary patency rates were 87.3%, 78.8% and 85.1%, respectively. Primary patency rates decreased depending on the number of patent run-off vessels (three 84.3%, two 80.8%, one 73.3%). Subgroup analysis showed that female patients had a significantly higher primary patency rate for BK bypasses (95.5% vs. 67.8%, P=0.037 ) compared to male patients. Subgroup analysis comparing patients younger and older than 70 years did not show a statistically significant difference in patency rates. Twenty-one patients underwent 42 reinterventions after bypass surgery. CONCLUSIONS: Present data show that the end-point heparin-bonded polytetrafluoroethylene graft yields patency rates comparable to those obtained with other graft material in above-knee locations. The encouraging results for BK bypasses suggests that this graft is an excellent option for small diameter vascular reconstructions when autologous vein is unavailable.

Detection of unstable carotid artery stenosis using MRI.

BACKGROUND AND PURPOSE: Carotid artery stenosis can be classified by magnetic resonance imaging (MRI) as lesion types I-VIII according to a modified histological scheme based on American Heart Association (AHA) guidelines. Lesion types IV-V and VI are regarded as high-risk plaques.We aimed to evaluate the clinical relevance of this classification for identifying unstable plaques. METHODS: Eighty-five patients (29 female) with severe carotid artery stenosis (diagnosed by Doppler and duplex ultrasonography) were imaged using a 1.5 T scanner with bilateral phased-array carotid coils. T1-, T2-, time-offlight (TOF) and proton-density (PD)-weighted studies were obtained. The carotid plaques were classified as lesion types III-VIII according to the MRI-modified AHA criteria. RESULTS: Thirty-five patients presented with a recently symptomatic stenosis; 50 patients were asymptomatic. Lesion types IV-V (51.4 % vs. 22 %) and VI (20 % vs. 4%; P < 0.0001) were found significantly more often in symptomatic patients compared to those without a history of cerebral ischemia. CONCLUSIONS: The distribution of lesion types differs significantly between symptomatic and asymptomatic carotid artery stenosis. High-risk lesion types IV-V and VI were overrepresented in recently symptomatic patients. MRI according to the modified AHA-criteria may be a suitable tool for detection of unstable carotid lesions.

[New developments in diagnostic and therapy of asymptomatic carotid stenosis]. / Aktuelles zur Diagnostik und Therapie der asymptomatischen Karotisstenose.

Stroke is the leading cause of long-term major disability in developed countries, although several improvements could be achieved in acute stroke therapy (e. g. thrombolysis, stroke-unit treatment, optimized early rehabilitation strategies). Therefore, primary prevention is essential to reduce the burden of stroke. 10 -20 % of all cerebral ischemias are caused due to stenosis or occlusion of the extracranial carotid arteries. This review summarizes the indications, diagnostics as well as the actual data for a medical, endovascular or operative treatment of asymptomatic carotid stenosis.

The relationship between volume and outcome following elective open repair of abdominal aortic aneurysms (AAA) in 131 German hospitals.

OBJECTIVES: Several studies indicate that high-volume hospitals have better results in open repair of unruptured abdominal aortic aneurysms (AAA). Up to now no studies had addressed this question in German hospitals. DESIGN: Post-hoc-analysis from a prospective physician-led registry. MATERIAL AND METHODS: Since 1999, the German Society for Vascular Surgery has conducted a prospective registry for open and endovascular repair of AAAs. This study includes 131 hospitals who conducted n=10163 elective open repairs for unruptured AAA between 1999 to 2004. All perioperative variables including annual volume as a continuous variable were analysed in a step-wise logistic regression model. In order to define a threshold annual volume an additional logistic regression analysis was performed by use of annual volume groups (0-9, 10-19, 20-29, 30-39, 40-49, 50 or more). The relationship between annual volume and further outcome parameters (length of procedure, blood transfusion, length of stay) were also analyzed. RESULTS: The overall mortality rate was 3.2%. The stepwise logistic regression model identified the following predictors of an increased perioperative mortality: age (OR 1.084, 95% CI 1.066-1.102), AAA diameter (OR 1.008, 95% CI 1.001-1.016), length of procedure (OR 1.008, 95% CI 1.006-1.009), ASA-Score (OR 2.636, 95% CI 2.129-3.264), suprarenal clamping (OR 1.447, 95% CI 1.008-2,078), blood transfusion (OR 1.786, 95% CI 1.268-2.514). Annual volume was moderately predictive (OR 1.003, 95% CI 1-1.006) but failed to reach statistical significance (p=0.07). The analysis of volume groups identified a significantly higher risk for hospitals with an annual volume of 1-9 AAA-repairs by comparison to hospitals with an annual volume of 50 or more AAA-repairs (OR 1.903, 95% CI 1.124-3.222). Operations at low volume hospitals were also longer (p<0.001), with an extended postoperative stay (p<0.001) and a higher transfusion rate (p<0.001). CONCLUSIONS: Patient's age, ASA classification, AAA diameter, length of procedure, suprarenal clamping and blood transfusion are predictive variables for an increased perioperative mortality in elective open AAA repair. Mortality is also increased by a low annual volume. Further studies are needed to examine whether these data are applicable to all German hospitals.

[Aneurysms and dissections of the thoracal and abdominal aorta]. / Aneurysmen und Dissektionen der thorakalen und abdominellen Aorta.

One to four per cent of all deaths in patients over 65 are caused by aneurysmatic diseases of the abdominal or thoracic aorta. For elective surgery in abdominal aneurysms, open surgery and endovascular treatment both demonstrate brilliant overall results. In the thoracic aorta, new endovascular procedures have led to considerable reductions of postoperative morbidity and mortality. Nevertheless, in view of the endovascular procedure's high cost and the still unclear long-term behaviour of the stent device, a second opinion from a specialised centre is an absolute necessity.

Association of circulating transforming growth factor beta, tumor necrosis factor alpha and basic fibroblast growth factor with restenosis after transluminal angioplasty.

OBJECTIVES: To assess prospectively the early time course of Transforming Growth Factor beta-1 (TGFbeta-1), basic Fibroblast Growth Factor (bFGF) and Tumor Necrosis Factor alpha (TNFalpha) as possible contributors to restenosis development after angioplasty. DESIGN: Prospective Study. METHODS: The levels of the soluble forms of these factors in the early response to Percutaneous Transluminal Angioplasty (PTA) in the arteries of the lower limb were prospectively assessed. 32 patients with peripheral arterial occlusive disease (PAOD), presenting with intermittent claudication (Fontaine stage IIb) were scheduled for angioplasty treatment. Serum levels of TGFbeta-1, TNFalpha and bFGF were assessed before intervention, 15 and 60 minutes after, 24 hours after as well as 2 and 4 weeks after intervention. We compared the distribution patterns between patients treated with balloon angioplasty and patients who required secondary stent implantation. Endpoint was the development of restenosis within 6 months after interventional treatment, defined as a lumen diameter reduction of more than 50% by ultrasound measurement compared to the result after PTA. RESULTS: The patients who later developed restenosis had significantly higher levels of TGFbeta-1 at 15 minutes, 24 hours and 2 weeks after PTA (p<0.05). TNFalpha and bFGF were only detected in a few patients and no significant change of serum levels was observed. CONCLUSION: The results demonstrate a possible role of TGFbeta-1 in the formation of restenosis after PTA.

Early endothelial and haematological response to cryoplasty compared with balloon angioplasty of the superficial femoral artery--a pilot study.

The purpose of the present study was to assess the course of adhesion molecules (intercellular adhesion molecule (ICAM), vascular cell adhesion molecule (VCAM), e-selectin, p-selectin and monocyte chemoatlractant protein 1 (MCP-1)), growth factors (transforming growth factor beta (TGFbeta) and basic fibroblast growth factor (bFGF)) and the cytokine tumour necrosis factor alpha (TNFalpha) after both angioplasty and cryoplasty. Recently cryoplasty has been suggested as a new method to oppose neointimal hyperplasia resulting in restenosis formation. While in vitro models have shown that the application of cryothermal energy to the endothelium during angioplasty leads to apoptosis induction and reduced proliferation rates, no human in vivo proof for an inhibition of neointimal hyperplasia exists. For restenosis initiation adhesion molecules, growth factors and cytokines play an important role. One possibility to investigate the endothelial response to angioplasty is the measurement of the soluble forms of adhesion molecules, growth factors and cytokines that are released into the circulation after denuding the vessel wall. In the present study we assessed the distribution pattern of the soluble forms of e-selectin, p-selectin, ICAM, VCAM, MCP-1, TGFbeta, bFGF and TNFalpha after angiography, angioplasty and cryoplasty of the femoropopliteal artery in the early course of 4 weeks in 29 patients with peripheral arterial occlusive disease. During the 4 weeks after intervention levels of e-selectin, ICAM, VCAM and MCP-1 increased after both angioplasty and cryoplasty. The course of the screened biomarkers was similar between angioplasty and cryoplasty. P-selectin and TGFbeta both decreased after cryoplasty, but not significantly. The present results show that the release of adhesion molecules, growth factors and cytokines is similar between balloon angioplasty and cryoplasty.

[Thrombosis of the inferior vena cava and the iliac and femoral veins in a 24-year old man]. / Thrombose der Vena cava inferior sowie der Iliacal- und Femoralvenen bei einem 24-jährigen Patienten.

HISTORY AND ADMISSION FINDINGS: A 24-year-old patient presented with nonspecific epigastric pain, general feebleness and weakness of both legs. The cardiopulmonary investigations were unremarkable. The abdomen was soft, without muscular resistance or local pressure tenderness. Both legs were moderately swollen without other findings. INVESTIGATIONS: The laboratory tests showed an elevated D-dimer and fibrinogen, as well as a heterozygous factor V Leiden mutation. Both duplex ultrasonography and computed tomography revealed thrombosis of the distal inferior vena cava (IVC) and both iliac and femoral veins. A short segment of the IVC between the left renal and intrahepatic veins was a-genetic. DIAGNOSIS, TREATMENT AND COURSE: Anticoagulation treatment with phenprocoumon was started for the deep vein thrombosis. At the one-year follow-up no thrombosis of the vena cava and the iliac and femoral veins was detected. CONCLUSION: Thrombosis of the IVC in combination with a pelvic vein thrombosis is a rare condition in young patients. If this venous abnormality is found, thrombophilia should be considered in the differential diagnosis. Anticoagulation is the treatment of choice.

MRI lesions after invasive therapy of carotid artery stenosis: a risk-modeling analysis.

BACKGROUND: Diffusion-weighted imaging (DWI) abnormalities can frequently be detected after carotid endarterectomy (CEA) and carotid angioplasty with stent placement (CAS) of the carotid arteries. We looked for possible predictors for the development of DWI lesions during the intervention. METHODS: We investigated 41 patients who underwent CAS without protection devices and 93 patients who underwent CEA. DWI studies were performed 1 day before and after the intervention. RESULTS: Ischemic complications consisted of two strokes (2.2%) in the CEA group and one stroke (2.4%) in the CAS group. DWI lesions were detected in 28.0% of all patients after intervention. Using a multivariate regression analysis, diabetes mellitus (DM), hyperlipidemia, symptomatic stenosis, age and CAS were found to be significant predictors for the occurrence of DWI lesions. CONCLUSIONS: DWI is an objective and highly sensitive method for monitoring interventions of the carotid arteries. Our results point to an increased risk of patients with diabetes and hyperlipidemia to develop DWI lesions during invasive therapy of the ICA.

[Controversies in the treatment of carotid stenoses. Present state of research and evidence-based medicine]. / Kontroversen in der Behandlung von Karotisstenosen. Studienstand und evidence-based medicine.

Endarterectomy for extracranial carotid stenosis has proven to be effective in the prophylaxis of carotid-related strokes by prospective, randomised trials (ECST, NASCET, ACAS, ACST). The safety and efficiency of carotid stenting has to be proven in prospective randomised trials comparing surgery and endovascular treatment.

Frequency, clinical significance and course of cerebral ischemic events after carotid endarterectomy evaluated by serial diffusion weighted imaging.

OBJECTIVES: Neurological deficit defines the outcome of Carotid Endarterectomy (CEA) that is mainly caused by cerebral ischemia. Diffusion-weighted imaging (DWI) is a sensitive method for demonstrating even small ischemic lesions. The aim of this study was to evaluate the frequency, clinical significance and course of ischemic lesions after CEA using serial DWI. METHODS: DWI was performed within 1 day before and after CEA in 88 patients. Postoperative lesions were analyzed by their quantity, volume and distribution. To differentiate temporary ischemia from definite cerebral infarction (blood brain barrier disruption) all patients with a positive postoperative DWI were reexamined with contrast-enhanced T1-MRI 7-10 days after the procedure. All patients were examined by a neurologist within 2 days before and after CEA. RESULTS: Two patients showed a postoperative neurological deficit. Postoperative DWI revealed ipsilateral ischemic lesions in 15 patients. In seven of these patients a brain infarction was diagnosed on the T1-MRI during follow-up. A significant correlation between the number of DWI lesions (p=0.031) as well as the volume of DWI lesions (p=0.023) and definite infarction was found. Symptomatic patients preoperatively showed significantly more DWI lesions (p=0.036) and cerebral infarcts (p=0.003). CONCLUSION: DWI is a sensitive method of demonstrating ischemic events after CEA. The number and volume of DWI lesions after CEA are highly predictive of brain infarction.

Semi-closed femoropopliteal thromboendarterectomy: a prospective study.

OBJECTIVE: to study the primary patency rates of angioscopically controlled thromboendarterectomies of the superficial femoral artery. DESIGN: prospective open study. METHODS: between 1990 and 1995, femoropopliteal thromboendarterectomies were performed in 63 patients (41 male, 22 female). Postoperative follow up was performed at 3- to 6-month intervals using non-invasive pressure measurements plus IVDSA at 1 year. RESULTS: eight patients were not evaluable, leaving 55 patients eligible for follow-up analysis. Postoperative complications (arteriovenous fistulas, false aneurysms) were observed in 5.4% of patients. Immediate perioperative occlusions occurred in 7.3%, early occlusions in 21.8% and late occlusions in 16.4% of all cases. The mean follow-up was approximately 57 months. The mean primary patency rate at 5 years was 44.5% (28 patients with the superficial femoral artery still open). Six patients died during the follow-up period. CONCLUSIONS: in contrast to the very positive reports found in recent literature, this prospective study shows a lower five-year patency rate for semi-closed femoropopliteal thromboendarterectomy than for bypass grafting. Thromboendarterectomy cannot be considered as a standard procedure in revascularisation of the femoropopliteal region.