The prospective GermanVasc cohort study.

Background: Previous observational studies reported a wide variation and possible room for improvement in the treatment of patients suffering from symptomatic peripheral artery disease (PAD). Yet, systematic assessment of everyday clinical practice is lacking. A General Data Protection Regulation (GDPR) compliant registry was developed and used to collect comprehensive data on clinical treatment and outcomes regarding PAD in Germany. Here, we report baseline characteristics of patients prospectively enrolled until the end of 2020. Methods: The GermanVasc registry study is a prospective longitudinal multicentre cohort study. Between 1st May 2018 and 31st December 2020, invasive endovascular, open-surgical, and hybrid revascularisations of patients suffering from chronic symptomatic PAD were prospectively included after explicit informed consent (NCT03098290). For ensuring high quality of the data, we performed comprehensive risk-based and random-sample external and internal validation. Results: In total, 5608 patients from 31 study centres were included (34% females, median 69 years). On-site monitoring visits were performed at least once in all centres. The proportion of chronic limb-threatening ischaemia was 30% and 13% were emergent admissions. 55% exhibited a previous revascularisation. Endovascular techniques made 69% among all documented invasive procedures (n=6449). Thirty-five percent were classified as patients with severe systemic disease, and 3% exhibited a constant threat to life according to the American Society of Anaesthesiologists classification. The risk profile comprised of 75% former or current smokers, 36% diabetes mellitus, and in 30% a current ischemic heart disease was present. At discharge, 93% of the patients received antiplatelets and 77% received statins. Conclusions: The GermanVasc registry study provides insights into real-world practice of treatment and outcomes of 5,608 patients with symptomatic PAD in Germany. The cohort covers a broader range of disease severity and types of interventions than usually found in trials. In future studies, comparative outcomes will be analysed in more detail.

Ex vivo characterization of carotid plaques by intravascular ultrasonography and virtual histology: concordance with real plaque pathomorphology.

BACKGROUND: The purpose of this study was to evaluate the accuracy of carotid plaque characterisation by virtual histology using intravascular ultrasonography (VH-IVUS) by comparing the results with real morphology. METHODS: Following elective carotid endarterectomy (CEA), atherosclerotic plaques from 36 patients (19 asymptomatic, 17 symptomatic) underwent ex-vivo VH-IVUS examination. Afterwards, tissue specimens were fixed with formalin and embedded in paraffin. Atherosclerotic lesions were characterised following hematoxylin/eosin (HE) and Elastin van Gieson (EvG) staining using AHA classification (stages I to VIII). The plaque composition, cellularity, severity of inflammation, and atheroma-associated macrophages and foam cells were compared with virtual histology. RESULTS: Patients with symptomatic carotid artery stenosis showed most commonly lesion type IV-V (N.=9; 52.9%), followed by type VI (N.=3; 17.6%) and type VII (N.=3, 17.6%), type VIII (N.=1; 5.9%) and type I-III (N.=1; 5.9%). In asymptomatic patients with the main lesion was type VII (N.=8; 42.1%), followed by type I-III (N.=4; 21.1%), type IV-V (N.=3, 15.8%) and type VIII (N.=1; 5.3%). The composition of unstable lesions differed significantly in symptomatic patients compared to asymptomatic subjects (70.1% vs. 31.6%, P=0.03). The concordance between the histological results and the VH-IVUS classification was 86.1% (Cohen`s kappa of 0.72). CONCLUSIONS: In the present study, our findings demonstrated significant correlation between true plaque composition determined by histology and VH-IVUS. Thus, IVUS might be useful as an additional diagnostic method to detect patients with unstable rupture-prone plaques.

PET/CT imaging of integrin αvß3 expression in human carotid atherosclerosis.

OBJECTIVES: The goal of this study was to evaluate the feasibility of [(18)F]Galacto-RGD positron emission tomography (PET)/computed tomography (CT) imaging of αvß3 expression in human carotid plaques. BACKGROUND: The integrin αvß3 is expressed by macrophages and angiogenic endothelial cells in atherosclerotic lesions and thus is a marker of plaque inflammation and, potentially, of plaque vulnerability. [(18)F]Galacto-RGD is a PET tracer binding specifically to αvß3. Therefore, [(18)F]Galacto-RGD PET/CT imaging of αvß3 expression in human carotid plaques might provide a novel noninvasive biomarker of plaque vulnerability. METHODS: [(18)F]Galacto-RGD PET/CT imaging was performed in 10 patients with high-grade carotid artery stenosis scheduled for carotid endarterectomy. Tracer uptake was measured in the stenotic areas of the carotid arteries, as well as on the contralateral side, and was corrected for blood pool activity, measured in the distal common carotid artery (target-to-background [TB] ratio). TB ratio was correlated with immunohistochemistry of αvß3 expression (LM609), macrophage density (CD68), and microvessel density (CD31) of the surgical specimen. In addition, ex vivo autoradiography of the surgical specimen with [(18)F]Galacto-RGD and competition experiments with an unlabeled αvß3-specific RGD peptide were performed. RESULTS: [(18)F]Galacto-RGD PET/CT showed significantly higher TB ratios in stenotic areas compared with nonstenotic areas (p = 0.01). TB ratios correlated significantly with αvß3 expression (R = 0.787, p = 0.026) and intensity of ex vivo autoradiography (R = 0.733, p = 0.038). Binding to atherosclerotic plaques was efficiently blocked in ex vivo competition experiments. A weak-to-moderate correlation was found with macrophage density (R = 0.367, p = 0.299) and microvessel density (R = 0.479, p = 0.176), which did not reach statistical significance. CONCLUSIONS: [(18)F]Galacto-RGD PET/CT shows specific tracer accumulation in human atherosclerotic carotid plaques, which correlates with αvß3 expression. Based on these initial data, larger prospective studies are now warranted to evaluate the potential of molecular imaging of αvß3 expression for assessment of plaque inflammation in patients.

Impact of chronic kidney disease on carotid plaque vulnerability.

OBJECTIVE: Little is known about the effect of chronic kidney disease (CKD) on plaque morphology in cerebral vessels. We therefore analyzed plaque composition and metabolic and chemical parameters with regard to clinical outcome in patients with advanced carotid artery stenosis (>70%) and normal or impaired renal function. METHODS: Carotid endarterectomy plaques were collected from 114 patients, 51 with CKD and 63 without CKD (mean estimated glomerular filtration rate, 49 ± 9 vs 88 ± 14 mL/min), and analyzed by histology and immunohistochemistry. Serum levels of matrix metalloproteinases (MMP-1, -2, -3, -7, -8, and -9), calcium, phosphate, parathyroid hormone, fetuin-A, osteoprotegerin, and inflammatory factors, including fibrinogen, and high-sensitive C-reactive protein (hsCRP) were measured by appropriate enzyme-linked immunosorbent assay. RESULTS: Compared with patients without CKD, patients with CKD had significantly more early-stage (11.2% vs 2.8%, P = .002) and end-stage (7.4% vs 0.2%, P = .036) calcification, unstable (50.8% vs 20.4%, P = .001) and ruptured (53.1% vs 32.8%, P = .035) lesions, and a significantly lower amount of collagenous fibers (39.2% vs 54.6%, P = .001). Serum samples of CKD patients had significantly enhanced levels of fibrinogen (393 ± 88 vs 331 ± 60 mg/dL, P = .018), hsCRP (1.7 ± 2.9 vs 0.8 ± 0.9 mg/dL; P = .042), parathyroid hormone (47.3 ± 24.1 vs 32.8 ± 12.2 ng/L, P = .010), fetuin-A (0.21 ± 0.05 vs 0.18 ± 0.04 mg/mL, P = .039), and MMP-7 (13.0 ± 5.3 vs 8.3 ± 3.0 ng/mL; P < 0.001). The incidence of cerebrovascular events >6 months before carotid surgery was significantly increased in CKD patients (84.0% vs 26.2% P < .001). CONCLUSIONS: In patients with CKD and advanced carotid artery stenosis, morphologic changes in plaque composition may contribute to plaque vulnerability and consequently to the risk of cerebrovascular events. Furthermore, relevant serum markers of inflammation, vascular calcification, and vessel wall degradation might be an indication of stroke risk in CKD patients.

Characterization of carotid artery plaques with USPIO-enhanced MRI: assessment of inflammation and vascularity as in vivo imaging biomarkers for plaque vulnerability.

To evaluate ultra small superparamagnetic iron oxide particles (USPIO) enhanced magnetic resonance (MR) imaging for characterization of atherosclerotic carotid plaques by assessing vascularity and plaque inflammation, besides contrast-enhanced MR angiography (CE-MRA) of the carotid artery stenosis. Twelve patients with severe carotid artery stenosis, scheduled for endarterectomy, underwent MRI of the carotid artery bifurcation using SHU 555 C at a dose of 40 µmol Fe/kg BW. The MR imaging protocol comprised pre- and post-contrast T2*-w, a first-pass CE-MRA and dynamic T1-w sequences. For quantitative data analysis, the signal intensities (SI) were measured and SNR-data (SNR = SI(blood/plaque/bone marrow)/standard deviation(noise)) as well as ΔSI-data (SNR(post)-SNR(pre)) were calculated. In addition, two radiologists rated the diagnostic performance of first-pass MRA according to a four level decision scale. Staining of anti-dextran (SHU 555 C) and anti-CD68 (macrophages) was performed for immunohistological confirmation. Plaque sections with a T2*-w signal decline (intracellular USPIO accumulation in macrophages) showed significantly changes (mean -14%, 95% CI, -5 to -20%; P < 0.01) and corresponding plaque regions had significantly higher (15.15 ± 1.76 vs. 5.22 ± 1.50; P < 0.01) T1-w enhancement data (global estimation of vascularity). The first-pass MRA of the supra-aortal vessels provided images of diagnostic quality. Representative immunohistology sections revealed colocalization of dextran- and CD68-immunoreactive cells. USPIO-enhanced MRI is feasible for in vivo assessment of vascularity and macrophage content in atherosclerotic carotid plaques, determining an association of these potential imaging biomarkers of plaque vulnerability. Diagnostic MRA of the supra-aortal vessels can be imaged additionally with a single administration of SHU 555 C.

Evaluation of serum matrix metalloproteinases as biomarkers for detection of neurological symptoms in carotid artery disease.

OBJECTIVE: Relevant soluble matrix metalloproteinases (MMPs), their inhibitors, tissue inhibitor of metalloproteinases (TIMPs), and serological factors were analyzed as possible biomarkers for neurological symptoms in patients with carotid artery stenosis. METHODS AND RESULTS: Asymptomatic (n = 76) and symptomatic (n = 69) patients were evaluated. Serum levels of collagenases (MMP-1, -8), gelatinases (MMP-2, -9), stromelysin (MMP-3), matrilysin (MMP-7), and TIMP-1, -2 were determined by enzyme-linked immunosorbant assay (ELISA). Furthermore, fibrinogen, C-reactive protein (CRP), leukocytes, and further serological parameters were measured. Circulating MMP-7, -8, -9, and TIMP-1 were significantly enhanced in symptomatic individuals with P < .001 for MMP-7 and P < .05 for MMP-8, -9, and TIMP-1. Significant correlations were found between various MMPs with highest correlation coefficient of r = .749 between MMP-8 and -9. In addition, MMP-1, -3, -7, -9 correlated significantly with leukocytes, MMP-1, and TIMP-1 with thrombocytes, MMP-8 with fibrinogen, and MMP-7 with creatinine. Combination of more than one biomarker led to significantly enhanced positive predictive value (PPV) for neurological symptom compared to single MMP (MMP-7 + MMP-9: PPV = 73.1%, MMP-7 + MMP-8 + MMP-9: PPV = 73.8% vs. PPV = 62.5%; P < .001). CONCLUSIONS: Thus, using appropriate analytical approaches, we showed for the first time the possibility to use set of relevant biomarkers as predictors of neurological symptoms. Such biomarkers together with current diagnostic techniques may further contribute to recognize vulnerable lesions to define patients at risk.

Fibrinogen and high-sensitive C-reactive protein as serologic predictors for perioperative cerebral microembolic lesions after carotid endarterectomy.

BACKGROUND: Neurologic deficit caused by cerebral ischemia defines the outcome of carotid endarterectomy (CEA). Although few patients have clinically evident neurologic deficit, diffusion-weighted imaging (DWI) presents a number of cases with ischemic brain lesions. This study should elucidate preoperative risk factors for perioperative microemboli that cause brain infarction. METHODS: We studied 183 patients (58 women, 69.2 +/-12.7 years; 125 men, 69.3 +/- 8.9 years) with high-degree carotid artery stenosis. DWI was performed before and after CEA to analyze new cerebral ischemia. Blood samples were obtained before operation to measure fibrinogen and C-reactive protein (CRP), and preoperative high-sensitive CRP (hsCRP) was analyzed in 30 consecutive patients. RESULTS: Postoperative DWI revealed new ipsilateral ischemic lesions in 41 patients (22.4%), and eight (4.4%) showed new neurologic deficit. Preoperative fibrinogen levels were higher in patients with new lesions (397.6 mg/dL +/- 104.7 mg/dL) than in those without (324.7 mg/dL +/- 74.2 mg/dL, P < .001). Preoperative levels of hsCRP were also higher in patients with new lesions (7.9 mg/dL +/- 5.2 mg/dL) than in those without (2.8 mg/dL +/- 2.6 mg/dL, P = .004). Significant association was found between fibrinogen and CRP (Spearman rho = 0.402; P < .001) as well as hsCRP (Spearman rho = 0.603, P = .003). No association was found between postoperative lesions and CRP (P = .833). CONCLUSION: The present study demonstrates that preoperative levels of fibrinogen and hsCRP are independent determinants for new periprocedural cerebral ischemic lesions caused by microembolic events. There is still not sufficient evidence to recommend measurement of CRP as a prognostic marker for perioperative cerebral lesion.

Role of adhesion molecules in the induction of restenosis after angioplasty in the lower limb.

OBJECTIVE: The adhesion molecules P selectin, E selectin, intercellular adhesion molecule, vascular cellular adhesion molecule (VCAM), and monocyte chemoattractant protein 1 play a important role in the development of arteriosclerotic lesions and are considered main contributors to restenosis after angioplasty. We expected that the serum levels of these markers would increase in the early phase of the first few weeks after angioplasty. METHODS: We assessed prospectively the levels of soluble forms of adhesion molecules on the day before and then 24 hours and 2 and 4 weeks after angioplasty in arteries of the lower limb by using enzyme-linked immunosorbent assays. We investigated the distribution pattern of these markers in 44 patients (25 male and 19 female; age, 67.7 +/- 8.5 years [mean +/- SD]) presenting with intermittent claudication (Fontaine stage IIb). Twelve patients (27.3%) underwent diagnostic angiography, 32 (72.2%) received interventional treatment, 22 (68.8%) received balloon angioplasty, and 10 (31.2%) required stent placement. RESULTS: Ten (31.3%) of the treated patients developed restenosis within 6 months. These patients had significantly higher levels of P selectin (P = .034), E selectin (P = .006), and VCAM (P = .050) at all time points. E selectin, VCAM, and monocyte chemoattractant protein 1 levels increased between 24 hours and 4 weeks after angiographic procedures, thus indicating that the angiographic procedure itself leads to activation and inflammation of the endothelium. CONCLUSIONS: This study emphasizes a meaningful role of the adhesion molecules E selectin, P selectin, and VCAM as interesting contributors to restenosis formation after percutaneous transluminal angioplasty.

Microembolic signals detected by transcranial Doppler sonography during carotid endarterectomy and correlation with serial diffusion-weighted imaging.

BACKGROUND AND PURPOSE: Embolic events are a major cause for procedure-related strokes after carotid endarterectomy (CEA). Transcranial Doppler sonography can reveal embolic events as microembolic signals (MES) during CEA. MES during declamping and shunting are frequently detected. MES during shunting are rare and known to be correlated with the neurological outcome of the patient. In the present study, we analyzed the occurrence of MES within different stages of CEA and whether MES within those stages were correlated with cerebral ischemia, as detected by diffusion-weighted imaging (DWI), and brain infarction, as detected by contrast-enhanced MRI. METHODS: Thirty-three patients were monitored intraoperatively for MES using transcranial Doppler sonography. DWI was performed within 24 hours before and after surgery. Positive postoperative DWI led to reexamination with contrast-enhanced T1-MRI 7 to 10 days after CEA for detection of cerebral infarction. RESULTS: MES were detected in 32 of 33 patients. The highest number of MES was found during shunting and declamping. A significant correlation was found between MES and DWI-lesions during dissection. A significant correlation was found between MES during dissection and shunting, and nonsignificant correlation was found between MES and the occurrence of cerebral infarction. CONCLUSIONS: MES could be regularly detected during CEA. Dissection and shunting seem to be the most vulnerable stages of the procedure.