Popliteal Artery Branching Variations: A Study on Multidetector CT Angiography.

Determining the branching pattern of the popliteal artery (PA) is an important step in planning some radiological and surgical procedures. The aim of this study was to investigate the course and morphology of the terminal branches of the popliteal artery using multidetector computed tomography (MDCT) angiography, and also to determine possible role gender in branching pattern. Three-hundred forty lower extremity MDCT angiography images for 170 patients (118 M, 52 F), who were between 20-80 years old, were examined. Popliteal artery branching types were grouped as percentage incidences. TPT diameters and lengths in Type IA extremities were compared based on gender and right or left side. Anterior tibial artery (ATA), posterior tibial artery (PTA) and peroneal artery dominance rates were calculated. 5000 times measurement data was mixed so that the cascade mean filter values were calculated for the right and left TPT length each time. It was observed that Type IA was the most common branching pattern (89.4%). The variational pattern incidence was 10.6% and the most common category was Type III (4.1%). The most common pattern was Type IB (3.2%). Variational pattern was 2 times more prevalent in females when compared to the males. The mean TPT diameter was 4.5 mm (2.7-7.3 mm) and there was no difference based on gender and the right-left side. The most common dominant artery for the right and left legs was PTA in both genders. The cut-off values calculated for the right and left TPT independent of gender were 31.30 ± 2.40 and 28.36 ± 2.58, respectively. Three new subtypes were identified as short (S ≤ 2 cm), standard (N = 2-4 cm) and long (L ≥ 4 cm) in Type IA, since it is in a wide variational range although it is a typical PA branching pattern.

Heterogeneous histomorphology, yet homogeneous vascular smooth muscle cell dedifferentiation, characterize human aneurysm disease.

OBJECTIVE: Abdominal aortic aneurysm (AAA) is a frequent, potentially life-threatening, disease that can only be treated by surgical means such as open surgery or endovascular repair. No alternative treatment is currently available, and despite expanding knowledge about the pathomechanism, clinical trials on medical aneurysm abrogation have led to inconclusive results. The heterogeneity of human AAA based on histologic examination is thereby generally neglected. In this study we aimed to further elucidate the role of these differences in aneurysm disease. METHODS: Tissue samples from AAA and popliteal artery aneurysm patients were examined by histomorphologic analysis, immunohistochemistry, Western blot, and polymerase chain reaction. The results were correlated with clinical data such as aneurysm diameter and laboratory results. RESULTS: The morphology of human AAA vessel wall probes varies tremendously based on the grade of inflammation. This correlates with increasing intima/media thickness and upregulation of the vascular endothelial growth factor cascade but not with any clinical parameter or the aneurysm diameter. The phenotypic switch of vascular smooth muscle cells occurred regardless of the inflammatory state and expressional changes of the transcription factors Kruppel-like factor-4 and transforming growth factor-ß lead to differential protein localization in aneurysmal compared with control arteries. These changes were in similar manner also observed in samples from popliteal artery aneurysms, which, however, showed a more homogenous phenotype. CONCLUSIONS: Heterogeneity of AAA vessel walls based on inflammatory morphology does not correlate with AAA diameter yet harbors specific implications for basic research and possible aneurysm detection.

Elevated plasma B-type natriuretic peptide concentration and resistive index, but not decreased aortic distensibility, associate with impaired blood flow at popliteal artery in type 2 diabetic patients.

Blood flow in lower extremity arteries is frequently impaired in diabetic patients even though they have a normal ankle-brachial index (ABI 1.0-1.4). Risk factors contributing to this lower extremity arterial disease have not been fully elucidated. We enrolled 52 type 2 diabetic patients with normal ABI and 30 age-matched nondiabetic subjects consecutively admitted to our hospital. Plasma B-type natriuretic peptide (BNP) concentrations were measured. Distensibility in ascending thoracic and abdominal aortas as well as total flow volume and resistive index at popliteal artery were evaluated by gated magnetic resonance imaging. An automatic device was used to measure ABI and brachial-ankle pulse-wave velocity (baPWV). Diabetic patients showed lower distensibility in ascending thoracic aorta (p<0.001) and total flow volume (p<0.001) and higher baPWV (p<0.001) and resistive index (p=0.005) and similar BNP and distensibility in abdominal aorta compared to nondiabetic subjects. Simple linear regression analyses revealed that distensibility in ascending thoracic (p=0.019) and abdominal (p=0.030) aortas positively as well as baPWV (p=0.020), resistive index (p<0.001) and BNP (p<0.001) negatively correlated with total flow volume. Stepwise multiple regression analysis demonstrated that increased BNP and resistive index were independent risk factors for total flow volume in diabetic patients (r(2)=0.639, p<0.001). These results indicate that increased plasma BNP levels and peripheral vascular resistance, but not decreased aortic distensibility, associate with impaired blood flow in lower extremity arteries in diabetic patients.

Popliteal artery aneurysms differ from abdominal aortic aneurysms in cellular topography and inflammatory markers.

OBJECTIVE: Popliteal artery aneurysms (PAAs) and abdominal aortic aneurysms (AAAs) frequently coincide; however, symptoms differ. We systematically assessed aneurysm cellular wall composition and inflammatory markers to compare both anatomic locations. METHODS: Aneurysmal walls of 38 PAAs and 198 AAAs were harvested from patients undergoing elective open surgical repair. Elastin, collagen, smooth muscle cells, iron, and inflammatory cells were quantified by immunohistochemistry. In addition, protease and cytokine levels were measured. RESULTS: Aneurysmal degradation resulted in similarly degraded media. The location of inflammation differed: the focus for T and B lymphocytes and plasma cells was the intima in PAAs (all P < .001) and the adventitia for AAAs (all P < .001). Iron was more often observed in PAAs than in AAAs (68% vs 1%; P < .001), indicating more previous intramural hemorrhages. Matrix metalloproteinase 2 activity was higher in PAAs than in AAAs (median [interquartile range], 0.363 [0.174-0.556] vs 0.187 [0.100-0.391]; P = .008), whereas matrix metalloproteinase 9 showed no difference. Walls of AAAs were richer in tested cytokine levels than were walls of PAAs. CONCLUSIONS: PAAs showed more signs of previous intramural hemorrhages compared with AAAs. In addition, inflammation in PAAs is mainly located in the intima, whereas its focus in AAAs is the adventitia. These results suggest important differences in the pathophysiologic mechanism of aneurysm formation between these locations and might explain the differences in presentation on diagnosis.

Alterations of specific biomarkers of metabolic pathways in vascular tree from patients with Type 2 diabetes.

The aims of this study were to check whether different biomarkers of inflammatory, apoptotic, immunological or lipid pathways had altered their expression in the occluded popliteal artery (OPA) compared with the internal mammary artery (IMA) and femoral vein (FV) and to examine whether glycemic control influenced the expression of these genes. The study included 20 patients with advanced atherosclerosis and type 2 diabetes mellitus, 15 of whom had peripheral arterial occlusive disease (PAOD), from whom samples of OPA and FV were collected. PAOD patients were classified based on their HbA1c as well (HbA1c ≤ 6.5) or poorly (HbA1c > 6.5) controlled patients. Controls for arteries without atherosclerosis comprised 5 IMA from patients with ischemic cardiomyopathy (ICM). mRNA, protein expression and histological studies were analyzed in IMA, OPA and FV. After analyzing 46 genes, OPA showed higher expression levels than IMA or FV for genes involved in thrombosis (F3), apoptosis (MMP2, MMP9, TIMP1 and TIM3), lipid metabolism (LRP1 and NDUFA), immune response (TLR2) and monocytes adhesion (CD83). Remarkably, MMP-9 expression was lower in OPA from well-controlled patients. In FV from diabetic patients with HbA1c ≤6.5, gene expression levels of BCL2, CDKN1A, COX2, NDUFA and SREBP2 were higher than in FV from those with HbA1c >6.5. The atherosclerotic process in OPA from diabetic patients was associated with high expression levels of inflammatory, lipid metabolism and apoptotic biomarkers. The degree of glycemic control was associated with gene expression markers of apoptosis, lipid metabolism and antioxidants in FV. However, the effect of glycemic control on pro-atherosclerotic gene expression was very low in arteries with established atherosclerosis.

The pathophysiology of abdominal aortic aneurysm growth: corresponding and discordant inflammatory and proteolytic processes in abdominal aortic and popliteal artery aneurysms.

OBJECTIVE: There is remarkable controversy over the processes driving abdominal aneurysm growth. The inherent limitations of animal and human studies hamper elucidation of the key inflammatory and proteolytic processes. Human data are largely derived from surgical specimens that typically reflect the final stages of the disease process and thus do not allow distinction between primary and secondary processes. Clear epidemiologic and genetic associations between abdominal aortic aneurysm (AAA) and popliteal artery aneurysms (PAA) suggest that that these two pathologies share common grounds. On this basis, we reasoned that information of corresponding and discordant processes in these aneurysms might provide critical clues on the processes that are crucial for aneurysm progression. METHODS: Messenger RNA (semi-quantitative real-time polymerase chain reaction) and protein analysis (enzyme-linked immunosorbent assay, multiplex, Western blotting), and histology were performed on aneurysm wall samples obtained during elective PAA and AAA repair. Nonaneurysmal aorta tissue from organ donors was included as reference. RESULTS: Messenger RNA and protein analysis showed that PAA and AAA are both characterized by a marked activation of nuclear factor-kappaB (NF-kappaB) and activator protein-1 (AP-1) proinflammatory transcription factors, and hyperexpression of interleukin (IL)-6 and IL-8. Discordant findings were found for other inflammatory markers such as interferon-gamma, interferon-inducible protein 10, tumor necrosis factor-alpha, monocyte chemotactic protein-1, and macrophage inflammatory protein 1alpha and beta, which were all lower in PAA. On the cellular level, both pathologies exhibited profuse infiltration of macrophages, neutrophils, and T-helper cells. Results for B cells, plasma cells, and cytotoxic T cells were discordant, with minimal infiltration of these cell types in PAA. Evaluation of protease expression and activation showed that both conditions are dominated by increased matrix metalloproteinase 8 and 9, and cathepsin K, L and S expression and activation. CONCLUSION: This explorative study characterizes degenerative aneurysmal disease general inflammatory conditions that are dominated by profound activation of the NF-kappaB and AP-1 pathways, hyperexpression of IL-6 and IL-8, and neutrophil involvement. Discordant findings for interferon gamma, cytotoxic T cells, B cells, and plasma cells challenge a critical role for these factors in the process of aneurysm growth. Pharmaceutic strategies targeting the common components in AAA and PAA may prove effective for the stabilization of AAA.

Cystic adventitial degeneration of the popliteal artery: lectin-histochemical study.

A case of cystic adventitial degeneration (CAD) of the popliteal artery is presented. Histologically the cyst appeared localised in the adventitia, outside the elastic lamina. A lectin-histochemical study evaluated the following peroxidase conjugated lectins: Peanut agglutinin, Concanavalin A, Ulex Europaeus (UEA I) and Wheat Germ Agglutinin. The lack of UEA I reactivity excluded an arterial origin of the cyst. Moreover, the lectin binding pattern of CAD appeared to be similar to the reactivity pattern of normal synovia.