High-resolution and accelerated multi-parametric mapping with automated characterization of vessel disease using intravascular MRI

BACKGROUND

Atherosclerosis is prevalent in cardiovascular disease, but present imaging modalities have limited capabilities for characterizing lesion stage, progression and response to intervention. This study tests whether intravascular magnetic resonance imaging (IVMRI) measures of relaxation times (T1, T2) and proton density (PD) in a clinical 3 Tesla scanner could characterize vessel disease, and evaluates a practical strategy for accelerated quantification.

METHODS

IVMRI was performed in fresh human artery segments and swine vessels in vivo, using fast multi-parametric sequences, 1-2 mm diameter loopless antennae and 200-300 μm resolution. T1, T2 and PD data were used to train a machine learning classifier (support vector machine, SVM) to automatically classify normal vessel, and early or advanced disease, using histology for validation. Disease identification using the SVM was tested with receiver operating characteristic curves. To expedite acquisition of T1, T2 and PD data for vessel characterization, the linear algebraic method ('SLAM') was modified to accommodate the antenna's highly-nonuniform sensitivity, and used to provide average T1, T2 and PD measurements from compartments of normal and pathological tissue segmented from high-resolution images at acceleration factors of R ≤ 18-fold. The results were validated using compartment-average measures derived from the high-resolution scans.

RESULTS

The SVM accurately classified ~80% of samples into the three disease classes. The 'area-under-the-curve' was 0.96 for detecting disease in 248 samples, with T1 providing the best discrimination. SLAM T1, T2 and PD measures for R ≤ 10 were indistinguishable from the true means of segmented tissue compartments.

CONCLUSION

High-resolution IVMRI measures of T1, T2 and PD with a trained SVM can automatically classify normal, early and advanced atherosclerosis with high sensitivity and specificity. Replacing relaxometric MRI with SLAM yields good estimates of T1, T2 and PD an order-of-magnitude faster to facilitate IVMRI-based characterization of vessel disease.

Variability in Atherosclerotic Disease Progression within the Infrainguinal Arterial Circulation is Dependent on Both Patient and Anatomical Factors

BACKGROUND

Studies suggest 25% of patients with symptomatic peripheral arterial disease develop symptom progression over time, yet there is minimal data related to actual atherosclerotic progression.

METHODS

Patients who underwent consecutive duplex imaging of the lower limb arteries, at least 6 months apart with no intervening arterial intervention, were identified. Atherosclerotic burden was determined for both femoropopliteal (FP) and crural (CR) arterial segments utilizing the Bollinger score (BoS). Overall change in BoS over time was determined, and patients were divided into group 1: disease progression and group 2: no change/disease regression. Patient demographics, comorbidities, and long-term outcomes were collated.

RESULTS

A total of 215 FP segments (155 men; median age 74 years) were assessed with 82 limbs showing atherosclerotic disease progression. FP atherosclerotic progression was associated with increased age, a diagnosis of ischemic heart disease and hypertension, and a lack of prescription of both an antiplatelet therapy and an angiotensin-converting enzyme inhibitor (all P < 0.05). FP atherosclerotic progression was also associated with an increased longer term mortality rate. A total of 272 CR arterial segments (190 men; median age 74 years) were assessed with 86 limbs showing atherosclerotic disease progression. CR atherosclerotic disease progression was associated with a diagnosis of diabetes mellitus at baseline (P = 0.019).

CONCLUSIONS

A number of variable factors predict atherosclerotic progression. Differences exist between factors and the arterial segments affected (FP/CR). This suggests that underlying atherosclerotic processes may vary depending on arterial segment, warranting further investigation.

Lower limb arterial calcification (LLAC) scores in patients with symptomatic peripheral arterial disease are associated with increased cardiac mortality and morbidity

AIMS

The association of coronary arterial calcification with cardiovascular morbidity and mortality is well-recognized. Lower limb arterial calcification (LLAC) is common in PAD but its impact on subsequent health is poorly described. We aimed to determine the association between a LLAC score and subsequent cardiovascular events in patients with symptomatic peripheral arterial disease (PAD).

METHODS

LLAC scoring, and the established Bollinger score, were derived from a database of unenhanced CT scans, from patients presenting with symptomatic PAD. We determined the association between these scores outcomes. The primary outcome was combined cardiac mortality and morbidity (CM/M) with a secondary outcome of all-cause mortality.

RESULTS

220 patients (66% male; median age 69 years) were included with follow-up for a median 46 [IQR 31-64] months. Median total LLAC scores were higher in those patients suffering a primary outcome (6831 vs. 1652; p = 0.012). Diabetes mellitus (p = 0.039), ischaemic heart disease (p = 0.028), chronic kidney disease (p = 0.026) and all-cause mortality (p = 0.012) were more common in patients in the highest quartile of LLAC scores. The area under the curve of the receiver operator curve for the LLAC score was greater (0.929: 95% CI [0.884-0.974]) than for the Bollinger score (0.824: 95% CI [0.758-0.890]) for the primary outcome. A LLAC score ≥ 4400 had the best diagnostic accuracy to determine the outcome measure.

CONCLUSION

This is the largest study to investigate links between lower limb arterial calcification and cardiovascular events in symptomatic PAD. We describe a straightforward, reproducible, CT-derived measure of calcification-the LLAC score.

Spectral Doppler ultrasound of peripheral arteries: a pictorial review

This article reviews the pathophysiology and sonographic findings of peripheral arterial lesions, with emphasis on the spectral Doppler waveforms encountered in each. It discusses the characteristic features of the Doppler spectra in obstructive conditions, including thromboembolism, atherosclerotic disease, bypass graft occlusion, dissection, trauma, and compartment syndrome, as well as non-obstructive conditions, including hyperemia, pseudoaneurysm, and arteriovenous fistula. Familiarity with the commonly-encountered spectral waveforms in the setting of these lesions is necessary for timely and accurate diagnosis and treatment.

Histological Analysis of a New Route after Subintimal Crural Angioplasty

BACKGROUND

Subintimal angioplasty is an alternative approach in treating critical limb ischemia with crural artery disease. However, route or location of the newly created channel is not understood.

CASE PRESENTATION

A 68-year-old man was referred to our hospital with ischemic gangrene of the right big toe. We performed endovascular treatment because he was a poor candidate for bypass surgery. The posterior tibial artery was treated using subintimal angioplasty, although it resulted in early occlusion. We decided that he was not able to receive any further limb salvage treatment and performed amputation below the knee 7 days after treatment. The specimen from the origin of posterior tibial artery to plantar artery bifurcation was resected and the formalin-fixed vessel was cut into 39 segments. Histological analysis showed that the newly formed lumen was comparatively well dilated and created in the media by tearing internal elastic lamina in almost the whole of its length. The severely poor runoff vessels below the ankle were thought to be a main cause of early occlusion.

CONCLUSIONS

The newly formed lumen by subintimal crural angioplasty could be well dilated and created in the media.

Pseudoxanthoma elasticum

Pseudoxanthoma elasticum (PXE) is a genetic metabolic disease with autosomal recessive inheritance caused by mutations in the ABCC6 gene. The lack of functional ABCC6 protein leads to ectopic mineralization that is most apparent in the elastic tissues of the skin, eyes and blood vessels. The clinical prevalence of PXE has been estimated at between 1 per 100,000 and 1 per 25,000, with slight female predominance. The first clinical sign of PXE is almost always small yellow papules on the nape and sides of the neck and in flexural areas. The papules coalesce, and the skin becomes loose and wrinkled. The mid-dermal elastic fibers are short, fragmented, clumped and calcified. Dystrophic calcification of Bruch's membrane, revealed by angioid streaks, may trigger choroidal neovascularization and, ultimately, loss of central vision and blindness in late-stage disease. Lesions in small and medium-sized artery walls may result in intermittent claudication and peripheral artery disease. Cardiac complications (myocardial infarction, angina pectoris) are thought to be relatively rare but merit thorough investigation. Ischemic strokes have been reported. PXE is a metabolic disease in which circulating levels of an anti-mineralization factor are low. There is good evidence to suggest that the factor is inorganic pyrophosphate (PPi), and that the circulating low levels of PPi and decreased PPi/Pi ratio result from the lack of ATP release by hepatocytes harboring the mutant ABCC6 protein. However, the substrate(s) bound, transported or modulated by the ABCC6 protein remain unknown. More than 300 sequence variants of the ABCC6 gene have been identified. There is no cure for PXE; the main symptomatic treatments are vascular endothelial growth factor inhibitor therapy (for ophthalmic manifestations), lifestyle, lipid-lowering and dietary measures (for reducing vascular risk factors), and vascular surgery (for severe cardiovascular manifestations). Future treatment options may include gene therapy/editing and pharmacologic chaperone therapy.

Galectin-3 in Peripheral Artery Disease. Relationships with Markers of Oxidative Stress and Inflammation

Galectin-3 is a modulator of oxidative stress, inflammation, and fibrogenesis involved in the pathogenesis of vascular diseases. The present study sought to characterize, in patients with peripheral artery disease (PAD), the localization of galectin-3 in arterial tissue, and to analyze the relationships between the circulating levels of galectin-3 and oxidative stress and inflammation. It also sought to compare the diagnostic accuracy of galectin-3 with that of other biochemical markers of this disease. We analyzed femoral or popliteal arteries from 50 PAD patients, and four control arteries. Plasma from 86 patients was compared with that from 72 control subjects. We observed differences in the expression of galectin-3 in normal arteries, and arteries from patients with PAD, with a displacement of the expression from the adventitia to the media, and the intima. In addition, plasma galectin-3 concentration was increased in PAD patients, and correlated with serologic markers of oxidative stress (F2-isoprostanes), and inflammation [chemokine (C−C motif) ligand 2, C-reactive protein, β-2-microglobulin]. We conclude that the determination of galectin-3 has good diagnostic accuracy in the assessment of PAD and compares well with other analytical parameters currently in use.

Inhibition of 14q32 microRNA miR-495 reduces lesion formation, intimal hyperplasia and plasma cholesterol levels in experimental restenosis

BACKGROUND AND AIMS

We aimed at investigating the role of 14q32 microRNAs in intimal hyperplasia and accelerated atherosclerosis; two major contributors to restenosis. Restenosis occurs regularly in patients treated for coronary artery disease and peripheral arterial disease. We have previously shown that inhibition of 14q32 microRNAs leads to increased post-ischemic neovascularization, and microRNA miR-494 also decreased atherosclerosis, while increasing plaque stability. We hypothesized that 14q32 microRNA inhibition has beneficial effects on intimal hyperplasia, as well as accelerated atherosclerosis.

METHODS

Non-constrictive cuffs were placed around both femoral arteries of C57BL/6J mice to induce intimal hyperplasia. Accelerated atherosclerotic plaque formation was induced in hypercholesterolemic ApoE^-/- mice by placing semi-constrictive collars around both carotid arteries. 14q32 microRNAs miR-329, miR-494 and miR-495 were inhibited in vivo using Gene Silencing Oligonucleotides (GSOs).

RESULTS

GSO-495 administration led to a 32% reduction of intimal hyperplasia. Moreover, the number of macrophages in the arterial wall of mice treated with GSO-495 was reduced by 55%. Inhibition of miR-329 and miR-494 had less profound effects on intimal hyperplasia. GSO-495 administration also decreased atherosclerotic plaque formation by 52% and plaques of GSO-495 treated animals showed a more stable phenotype. Finally, cholesterol levels were also decreased in GSO-495 treated animals, via reduction of the VLDL-fraction.

CONCLUSIONS

GSO-495 administration decreased our primary outcomes, namely intimal hyperplasia, and accelerated atherosclerosis. GSO-495 administration also favourably affected multiple secondary outcomes, including macrophage influx, plaque stability and total plasma cholesterol levels. We conclude that 14q32 microRNA miR-495 is a promising target for prevention of restenosis.

Impact of Indoxyl Sulfate on Progenitor Cell-Related Neovascularization of Peripheral Arterial Disease and Post-Angioplasty Thrombosis of Dialysis Vascular Access

Patients with chronic kidney disease (CKD) have an increased risk of vascular disease, which is associated with considerable health care costs. Vascular disease in CKD differs clinically and pathobiologically from that in patients with normal renal function. Besides the traditional risk factors, retention of uremic toxins contributes to the pathogenesis of vascular disease in patients with CKD. Indoxyl sulfate is a protein-bound uremic toxin and is inefficiently removed by conventional dialysis. Accumulating evidence suggests that indoxyl sulfate is a vascular toxin involved in atherosclerosis, arteriosclerosis, vascular calcification and vascular repair. Clinically, indoxyl sulfate is associated with total and cardiovascular mortality in patients with CKD. Recent studies have indicated that in addition to coronary and cerebral arteries, indoxyl sulfate plays a role in peripheral artery disease (PAD) and dialysis graft thrombosis. Emerging evidence suggests that indoxyl sulfate is implicated via novel mechanisms, including progenitor cell-related neovascularization and tissue factor-related hypercoagulability. These findings raise the possibility that strategies targeting serum indoxyl sulfate may have the potential to improve the outcomes of PAD and dialysis vascular access in patients with CKD.

[POSSIBILITIES OF THE FORCED INTRAARTERIAL INJECTION OF MEDICINAL PREPARATIONS IN A COMPLEX OF TREATMENT FOR THE LOWER EXTREMITIES CHRONIC ISCHEMIA]

The efficacy and prognostic significance of the forced intraarterial injection of medicinal preparations in complex of treatment in patients, suffering chronic ischemia of the lower extremities tissues, was studied. In experimental conditions of the main blood flow blockade the forced intraarterial injection of medicinal preparations have promoted the release of vessels from cellular aggregates and the blood clots; and in the ischemia of degree ІІ - ІІІа – has determined more pronounced clinical improvement. Appearance of reactive hyperemia of the foot in terms more than 2 min have witnessed the hopelessness of the extremity saving.

Image Quality and Stenosis Assessment of Non-Contrast-Enhanced 3-T Magnetic Resonance Angiography in Patients with Peripheral Artery Disease Compared with Contrast-Enhanced Magnetic Resonance Angiography and Digital Subtraction Angiography

PURPOSE

To evaluate the diagnostic performance of flow-sensitive dephasing (FSD)-prepared steady-state free precession (SSFP) magnetic resonance angiography (MRA) at 3 T for imaging infragenual arteries relative to contrast-enhanced MRA (CE-MRA) and digital subtraction angiography (DSA).

MATERIALS AND METHODS

A series of 16 consecutive patients with peripheral arterial disease (PAD) underwent a combined peripheral MRA protocol consisting of FSD-MRA for the calves and large field-of-view CE-MRA. DSA was performed on all patients within 1 week of the MR angiographies. Image quality and degree of stenosis was assessed by two readers with rich experience. Inter-observer agreement was determined using kappa statistics. Receiver operating characteristic (ROC) curve analysis determined the diagnostic value of FSD-MRA, CE-MRA, and CE-MRA combined with FSD-MRA (CE+FSD MRA) in predicting vascular stenosis.

RESULTS

At the calf station, no significantly difference of subjective image quality scores was found between FSD-MRA and CE-MRA. Inter-reader agreement was excellent for both FSD-MRA and CE-MRA. Both of FSD-MRA and CE-MRA carry a stenosis overestimation risk relative to DSA standard. With DSA as the reference standard, ROC curve analysis showed that the area under the curve was largest for CE+FSD MRA. The greatest sensitivity and specificity were obtained when a cut-off stenosis score of 2 was used.

CONCLUSION

In patients with severe PAD,3 T FSD-MRA provides good-quality diagnostic images without a contrast agent and is a good supplement for CE-MRA. CE+FSD MRA can improve the accuracy of vascular stenosis diagnosis.

The Association of Peri-Procedural Blood Transfusion with Morbidity and Mortality in Patients Undergoing Percutaneous Lower Extremity Vascular Interventions: Insights from BMC2 VIC

Objective

To determine the predictors of periprocedural blood transfusion and the association of transfusion on outcomes in high risk patients undergoing endoluminal percutaneous vascular interventions (PVI) for peripheral arterial disease.

Methods/Results

Between 2010–2014 at 47 hospitals participating in a statewide quality registry, 4.2% (n = 985) of 23,273 patients received a periprocedural blood transfusion. Transfusion rates varied from 0 to 15% amongst the hospitals in the registry. Using multiple logistic regression, factors associated with increased transfusion included female gender (OR = 1.9; 95% CI: 1.6–2.1), low creatinine clearance (1.3; 1.1–1.6), pre-procedural anemia (4.7; 3.9–5.7), family history of CAD (1.2; 1.1–1.5), CHF (1.4; 1.2–1.6), COPD (1.2; 1.1–1.4), CVD or TIA (1.2; 1.1–1.4), renal failure CRD (1.5; 1.2–1.9), pre-procedural heparin use (1.8; 1.4–2.3), warfarin use (1.2; 1.0–1.5), critical limb ischemia (1.7; 1.5–2.1), aorta-iliac procedure (1.9; 1.5–2.5), below knee procedure (1.3; 1.1–1.5), urgent procedure (1.7; 1.3–2.2), and emergent procedure (8.3; 5.6–12.4). Using inverse weighted propensity matching to adjust for confounders, transfusion was a significant risk factor for death (15.4; 7.5–31), MI (67; 29–150), TIA/stroke (24; 8–73) and ARF (19; 6.2–57). A focused QI program was associated with a 28% decrease in administration of blood transfusion (p = 0.001) over 4 years.

Conclusion

In a large statewide PVI registry, post procedure transfusion was highly correlated with a specific set of clinical risk factors, and with in-hospital major morbidity and mortality. However, using a focused QI program, a significant reduction in transfusion is possible.

Plaque Composition in the Proximal Superficial Femoral Artery and Peripheral Artery Disease Events

OBJECTIVES

The aim of this study was to describe associations of the presence of lipid-rich necrotic core (LRNC) in the proximal superficial femoral artery (SFA) with lower extremity peripheral artery disease (PAD) event rates and systemic cardiovascular event rates.

BACKGROUND

LRNC in the coronary and carotid arteries is associated with adverse outcomes but has not been studied previously in lower extremity arteries.

METHODS

Participants with ankle-brachial index (ABI) values <1.00 were identified from Chicago medical centers and followed annually. Magnetic resonance imaging was used to characterize SFA atherosclerotic plaque at baseline. Medical records for hospitalizations and procedures after baseline were adjudicated for lower extremity revascularization, amputation, and critical limb ischemia and also for new coronary events, ischemic stroke, and mortality.

RESULTS

Of 254 participants with PAD, 62 (24%) had LRNC and 149 (59%) had calcium in the SFA at baseline. Cox regression analyses were adjusted for age, sex, race, comorbidities, baseline ABI, and other confounders. SFA LRNC was associated with an increased incidence of the combined outcome of lower extremity amputation, critical limb ischemia, ABI decline >0.15, and revascularization at 47-month follow-up (hazard ratio: 2.18; 95% confidence interval: 1.27 to 3.75; p = 0.005). The association of SFA LRNC with PAD events was maintained even when this combined outcome excluded lower extremity revascularization (hazard ratio: 2.58; 95% confidence interval: 1.25 to 5.33; p = 0.01). LRNC in the SFA was not associated with all-cause mortality, acute coronary events, or stroke.

CONCLUSIONS

Among patients with PAD, LRNC in the SFA was associated with higher rates of clinical PAD events, and this association was independent of ABI. Further study is needed to determine whether interventions that reduce SFA LRNC prevent PAD events.

A Novel Index Using Ankle Hemodynamic Parameters to Assess the Severity of Peripheral Arterial Disease: A Pilot Study

In peripheral arterial disease (PAD) of the lower extremities, the presence of flow-limiting stenoses can be objectively detected by the ankle-brachial index (ABI). However, the severity of ischemic symptoms is not necessarily associated with the ABI value. Atherosclerotic plaque in lower extremity PAD induces ankle arterial stiffness and reduces ankle vascular resistance, which may decrease ankle blood flow and cause ischemic symptoms. We hypothesized that the ankle hemodynamic index (AHI), defined as the ratio of ankle arterial stiffness to ankle vascular resistance, could be used to assess the blood supply deficiency in a diseased lower limb in patients with PAD. The 85 consecutive patients with PAD who were retrospectively analyzed in this study had Rutherford grade 1 to grade 6 ischemia diagnosed as PAD and significant stenotic lesions (>50% diameter stenosis) of the lower extremity on contrast angiography. The AHI was calculated as the product of the ankle pulse pressure and the ratio of heart rate to ankle mean arterial pressure (ankle pulse pressure × heart rate/ankle mean arterial pressure). The Rutherford grade was significantly correlated with the AHI (r = 0.50, P < 0.001), but not with the ABI (r = 0.07, P = 0.52). Multiple ordinal regression analysis showed that anemia (odds ratio 0.66, P = 0.002) and AHI (odds ratio 1.04, P = 0.02) were independently associated with Rutherford grade. Our study shows that AHI, a novel parameter based on the ABI measurement, is well correlated with ischemic symptoms, and may be a useful means to assess the arterial blood supply of the lower extremities of patients with PAD.

Talin and vinculin are downregulated in atherosclerotic plaque; Tampere Vascular Study

BACKGROUND AND AIMS

Focal adhesions (FA) play an important role in the tissue remodeling and in the maintenance of tissue integrity and homeostasis. Talin and vinculin proteins are among the major constituents of FAs contributing to cellular well-being and intercellular communication.

METHODS

Microarray analysis (MA) and qRT-PCR low-density array were implemented to analyze talin-1, talin-2, meta-vinculin and vinculin gene expression in circulating blood and arterial plaque.

RESULTS

All analyzed genes were significantly and consistently downregulated in plaques (carotid, abdominal aortic and femoral regions) compared to left internal thoracic artery (LITA) control. The use of LITA samples as controls for arterial plaque samples was validated using immunohistochemistry by comparing LITA samples with healthy arterial samples from a cadaver. Even though the differences in expression levels between stable and unstable plaques were not statistically significant, we observed further negative tendency in the expression in unstable atherosclerotic plaques. The confocal tissue imaging revealed gradient of talin-1 expression in plaque with reduction close to the vessel lumen. Similar gradient was observed for talin-2 expression in LITA controls but was not detected in plaques. This suggests that impaired tissue mechanostability affects the tissue remodeling and healing capabilities leading to development of unstable plaques.

CONCLUSIONS

The central role of talin and vinculin in cell adhesions suggests that the disintegration of the tissue in atherosclerosis could be partially driven by downregulation of these genes, leading to loosening of cell-ECM interactions and remodeling of the tissue.

Vascular Disease and Risk Stratification for Ischemic Stroke and All-Cause Death in Heart Failure Patients without Diagnosed Atrial Fibrillation: A Nationwide Cohort Study

Background

Stroke and mortality risk among heart failure patients previously diagnosed with different manifestations of vascular disease is poorly described. We conducted an observational study to evaluate the stroke and mortality risk among heart failure patients without diagnosed atrial fibrillation and with peripheral artery disease (PAD) or prior myocardial infarction (MI).

Methods

Population-based cohort study of patients diagnosed with incident heart failure during 2000–2012 and without atrial fibrillation, identified by record linkage between nationwide registries in Denmark. Hazard rate ratios of ischemic stroke and all-cause death after 1 year of follow-up were used to compare patients with either: a PAD diagnosis; a prior MI diagnosis; or no vascular disease.

Results

39,357 heart failure patients were included. When compared to heart failure patients with no vascular disease, PAD was associated with a higher 1-year rate of ischemic stroke (adjusted hazard rate ratio [HR]: 1.34, 95% confidence interval [CI]: 1.08–1.65) and all-cause death (adjusted HR: 1.47, 95% CI: 1.35–1.59), whereas prior MI was not (adjusted HR: 1.00, 95% CI: 0.86–1.15 and 0.94, 95% CI: 0.89–1.00, for ischemic stroke and all-cause death, respectively). When comparing patients with PAD to patients with prior MI, PAD was associated with a higher rate of both outcomes.

Conclusions

Among incident heart failure patients without diagnosed atrial fibrillation, a previous diagnosis of PAD was associated with a significantly higher rate of the ischemic stroke and all-cause death compared to patients with no vascular disease or prior MI. Prevention strategies may be particularly relevant among HF patients with PAD.

[THROMBOANGIITIS OBLITERANS OVERLAPPING WITH ATHEROSCLEROTIC OCCLUSIVE ARTERIAL DISEASE: SMALL MESENTERIC ARTERY INVOLVEMENT BY THROMBOANGIITIS OBLITERANS]

INTRODUCTION

Thromboangiitis obliterans is an inflammatory occlusive vascular disease of young smokers that commonly involves the small and medium sized arteries and veins of the extremities. An important differential diagnosis of thromboangiitis obliterans is atherosclerotic arterial disease. An atypical presentation of thromboangiitis obliterans by involvement of mesenteric arteries has been described sporadically.

CASE PRESENTATION

We report the case of a patient presenting with Raynaud's phenomenon, ischemia of the upper and lower extremities, as well as mesenteric ischemia. The dramatic course of the disease advanced to gangrene of the calves and intestinal infarction. In this patient, angiographic and histologic features were consistent with thromboangiitis obliterans associated with atherosclerotic arteriopathy.

DISCUSSION

A review of the literature revealed 31 reported cases of mesenteric artery involvement by thromboangiitis obliterans. The overlap between thromboangiitis obliterans and atherosclerotic arteriopathy is rare but has recently focused attention in the literature.

CONCLUSION

In the differential diagnosis of mesenteric ischemia, thromboangiitis obliterans is a rare but important diagnosis that should be considered. In view of shared features of thromboangiitis obliterans and peripheral artery disease, awareness of their possible coexistence is needed in order to make the right diagnosis and offer proper treatment.

Transgenic Overexpression of Tissue-Nonspecific Alkaline Phosphatase (TNAP) in Vascular Endothelium Results in Generalized Arterial Calcification

BACKGROUND

Ectopic vascular calcification is a common condition associated with aging, atherosclerosis, diabetes, and/or chronic kidney disease. Smooth muscle cells are the best characterized source of osteogenic progenitors in the vasculature; however, recent studies suggest that cells of endothelial origin can also promote calcification. To test this, we sought to increase the osteogenic potential of endothelial cells by overexpressing tissue-nonspecific alkaline phosphatase (TNAP), a key enzyme that regulates biomineralization, and to determine the pathophysiological effect of endothelial TNAP on vascular calcification and cardiovascular function.

METHODS AND RESULTS

We demonstrated previously that mice transgenic for ALPL (gene encoding human TNAP) develop severe arterial medial calcification and reduced viability when TNAP is overexpressed in smooth muscle cells. In this study, we expressed the ALPL transgene in endothelial cells following endothelial-specific Tie2-Cre recombination. Mice with endothelial TNAP overexpression survived well into adulthood and displayed generalized arterial calcification. Genes associated with osteochondrogenesis (Runx2, Bglap, Spp1, Opg, and Col2a1) were upregulated in the aortas of endothelial TNAP animals compared with controls. Lesions in coronary arteries of endothelial TNAP mice showed immunoreactivity to Runx2, osteocalcin, osteopontin, and collagen II as well as increased deposition of sialoproteins revealed by lectin staining. By 23 weeks of age, endothelial TNAP mice developed elevated blood pressure and compensatory left ventricular hypertrophy with preserved ejection fraction.

CONCLUSIONS

This study presented a novel genetic model demonstrating the osteogenic potential of TNAP-positive endothelial cells in promoting pathophysiological vascular calcification.

The association of bone and osteoclasts with vascular calcification

The presence of bone tissue in calcified arteries may provide insights into the pathophysiology and potential reversibility of calcification, but the prevalence, distribution, and determinants of bone and osteoclasts in calcified arteries are unknown. Specimens of 386 arteries from lower limb amputations in 108 patients were examined retrospectively. Calcification was present in 282 arteries from 89 patients, which was medial in 64%, intimal in 9%, and both in 27%. Bone was present in 6% of arteries, essentially all of which were heavily calcified. Multiple sampling revealed that the true prevalence of bone in heavily calcified arteries was 25%. Bone was more common in medial rather than intimal calcifications (10% vs 3%, p=0.03) but did not vary with artery location (above vs below the knee). Heavily calcified arteries with bone were more likely to come from patients who were older (p=0.04), had diabetes (p=0.06), or were receiving warfarin (p=0.06), but there was no association with gender or renal failure. Bone was almost always adjacent to calcifications, along the periphery, but never within. Staining for the bone-specific proteins osteocalcin and osterix was noted in 20% and 45% of heavily calcified arteries without visible bone. Osteoclasts were present in 4.9% of arteries, all of which were heavily calcified and most of which contained bone. The frequent absence of bone in heavily calcified vessels and the histologic pattern strongly suggests a secondary rather than primary event. Recruitment of osteoclasts to vascular calcifications can occur but is rare, suggesting a limited capacity to reverse calcifications.

Risk Stratification of Patients with Peripheral Arterial Disease and Abdominal Aortic Aneurysm Using Aortic Augmentation Index

Background

Central augmentation index (cAIx) is an indicator for vascular stiffness. Obstructive and aneurysmatic vascular disease can affect pulse wave propagation and reflection, causing changes in central aortic pressures.

Aim

To assess and compare cAIx in patients with peripheral arterial disease (PAD) and / or abdominal aortic aneurysm (AAA).

Methods

cAIx was assessed by radial applanation tonometry (Sphygmocor) in a total of 184 patients at a tertiary referral centre. Patients were grouped as having PAD only, AAA only, or both AAA and PAD. Differences in cAIx measurements between the three patient groups were tested by non-parametric tests and stepwise multivariate linear regression analysis to investigate associations with obstructive or aneurysmatic patterns of vascular disease.

Results

In the study sample of 184 patients, 130 had PAD only, 20 had AAA only, and 34 patients had both AAA and PAD. Mean cAIx (%) was 30.5 ± 8.2 across all patients. It was significantly higher in females (35.2 ± 6.1, n = 55) than males (28.4 ± 8.2, n = 129), and significantly higher in patients over 80 years of age (34.4 ± 6.9, n = 22) than in those under 80 years (30.0 ± 8.2, n = 162). Intergroup comparison revealed a significant difference in cAIx between the three patient groups (AAA: 27.3 ± 9.5; PAD: 31.4 ± 7.8; AAA & PAD: 28.8 ± 8.5). cAIx was significantly lower in patients with AAA, higher in patients with both AAA and PAD, and highest in patients with PAD only (beta = 0.21, p = 0.006).

Conclusion

Non-invasive assessment of arterial stiffness in high-risk patients indicates that cAIx differs according to the pattern of vascular disease. Measurements revealed significantly higher cAIx values for patients with obstructive peripheral arterial disease than for patients with aneurysmatic disease.

Histomorphological evaluation of atherosclerotic lesions in patients with peripheral artery occlusive disease

PURPOSE

Peripheral arterial occlusive disease (PAOD) is mainly caused by atherosclerosis of the vessel wall. These pathological changes are classified into different stages and are well described for carotid and coronary vessels, but not for PAOD. The aim of our study was to analyze plaque morphology of femoral arteries in patients with intermittent claudication and critical limb ischemia.

PATIENTS AND METHODS

In this retrospective study 85 atherosclerotic plaques (common and superficial femoral artery) of 71 patients with a clinical symptomatic PAOD were analyzed, by histology (01/2009-07/2010). Atherosclerotic lesions were classified according to Stary (type I-VIII). For further characterization, plaques were evaluated for the presence of collagen, elastin, calcifications, smooth muscle cells, macrophages, leucocytes, and cellularity.

RESULTS

The majority (91%) of atherosclerotic lesions were of advanced types according to Stary (V-VII). Atherosclerotic lesion type VI was associated with significant higher amount of inflammatory cells in comparison to all other atherosclerotic plaque types (CD45: p<0.001; CD68: p=0.013). In addition, atherosclerotic plaques with a pronounced neovascularization contained a higher amount of CD45 (p=0.015; rho=0.273) and CD68 (p=0.016; rho=0.275) positive cells.

CONCLUSION

Atherosclerotic lesions of femoral arteries show similar morphological changes as coronary or carotid arteries. But inflammatory cells had a higher impact on plaque progression and destabilization than any other factor.

[THE METHOD OF TREATMENT OF LYMPHORRHEA AFTER RECONSTRUCTION OF THE LOWER EXTREMITIES ARTERIES]

Lymphorrhea have had occur after performance of 1381 reconstructive operative interventions on arteries of the lower extremities in 42 (3.04%) of patients. While application of 76% solution of triombrast and further elastic compression in 83.3% observations a good result was achieved, in 16.7%--satisfactory.

Dixon-based fat-free MR-angiography compared to first pass and steady-state high-resolution MR-angiography using a blood pool contrast agent

INTRODUCTION

Compared to standard arterial-only first-pass MR-angiography (FPMRA), imaging during the equilibrium phase of a blood pool contrast agent (steady state) has been shown to provide higher image quality and better stenosis grading. Homogenous Dixon fat-suppression promises to increase contrast by suppression of fat adjacent to vessels. This study was performed to compare diagnostic image quality and vessel-to-background contrasts in equilibrium phase Dixon-based fat-free MRA (DFSMRA) of run-off vessels to FPMRA imaging and equilibrium phase T1-weighted non-fat-suppressed ultra-high resolution MRA (SSMRA).

MATERIAL AND METHODS

In a prospective, intra-individual comparative study, 17 patients with known or suspected peripheral arterial occlusive disease (PAOD; 11 men, mean age 65.6±18.1 [23-89] years) received FPMRA, DFSMRA, and SSMRA at 1.5 Tesla using a clinical whole body MRI scanner. All sequences were performed within the same session applying a single dose of a blood pool contrast agent (gadofosveset trisodium) that was injected during acquisition of FPMRA. The diagnostic image quality of the run-off vessels was evaluated on a 3-point scale. Quantitative analysis consisted of contrast-ratio (CR) measurements of vascular lumen signals compared to signals of adjacent muscle and fat.

RESULTS

The average image quality of vessel visualization was rated highest in SSMRA (mean 1.34±0.41), followed by standard FPMRA (mean 1.15±0.33) and DFSMRA (mean 0.99±0.61). Image quality was rated similarly high in the thighs and pelvic region, whereas small vessels in the lower legs and in the feet were best visualized by SSMRA. CR of vascular lumen compared to adjacent fatty tissue was 2.7 times higher in DFSMRA compared to SSMRA, whereas CR of vascular lumen to muscle was 1.3 times higher in SSMRA.

CONCLUSION

Vessel to fat contrast is strongly increased in DFSMRA compared to T1-weighted ultra-high resolution non-fat suppressed SSMRA, whereas vessel to muscle contrast is decreased in DFSMRA. Given the current technical limitations of DFSMRA, possible benefits are outweighed by advantages of first-pass imaging regarding arterial selectivity as well as advantages of SSMRA with respect to spatial resolution.

Baseline Platelet Activation and Reactivity in Patients with Critical Limb Ischemia

Background

Patients with critical limb ischemia (CLI) have a high risk to develop cardiovascular events (CVE). We hypothesized that in CLI patients platelets would display increased baseline activation and reactivity.

Objectives

We investigated baseline platelet activation and platelet reactivity in patients with CLI.

Patients/Methods

In this study baseline platelet activation and platelet reactivity in response to stimulation of all major platelet activation pathways were determined in 20 CLI patients (11 using aspirin and 9 using vitamin K-antagonists) included in the Juventas-trial (clinicaltrials.gov NCT00371371) and in 17 healthy controls. Platelet activation was quantified with flow cytometric measurement of platelet P-selectin expression and fibrinogen binding.

Results

CLI patients not using aspirin showed higher baseline platelet activation compared to healthy controls. Maximal reactivity to stimulation of the collagen and thrombin activation pathway was decreased in CLI patients compared to healthy controls. In line, attenuated platelet reactivity to stimulation of multiple activation pathways was associated with several traditional risk factors for cardiovascular disease.

Conclusions

Baseline platelet activation was increased in CLI patients, whereas the reactivity of circulating platelets to several stimulatory agents is decreased. Reactivity of platelets was inversely correlated with cardiovascular risk factors.