Arthur Tarricone

Genotype-Dependent Impairment of Hemoglobin Clearance Increases Oxidative and Inflammatory Response in Human Diabetic Atherosclerosis

Objective—Haptoglobin (Hp) protein is responsible for hemoglobin clearance after intra-plaque hemorrhage. Hp gene exists as Hp-1 and Hp-2 alleles and the phenotypes show important molecular heterogeneity. We tested the hypothesis that hemoglobin clearance may be deficient in diabetic atheroma from patients with Hp2-2, triggering increased oxidative, inflammatory, and angiogenic patterns compared with controls. Methods and Results—Forty patients with diabetes mellitus were genotyped and their peripheral plaques compared after atherectomy. Plaque hemorrhage, iron content, hemoglobin-binding protein CD163, and heme-oxygenase-1 were quantified. Oxidative, inflammatory, and angiogenic patterns were evaluated by measuring myeloperoxidase, interleukin-10, macrophages, vascular cell adhesion molecule-1, smooth muscle actin, and plaque neovascularization (CD34/CD31). Plaques with Hp2-2 (n=7) had increased hemorrhage (P<0.005), iron content (P<0.001), and reduced CD163 expression (P<0.002) compared with controls (n=14). Hp2-2 plaques had increased heme-oxygenase-1 protein (P<0.02), myeloperoxidase gene (P<0.05), and protein (P<0.0001). Anti-inflammatory interleukin-10 gene (P<0.04), and protein expressions (P<0.0001) were decreased in Hp2-2. Finally, macrophage (P<0.0001), vascular cell adhesion molecule-1 (P=0.001), smooth muscle actin (P=0.002) scores, and neovessels density (P<0.0001) were increased in Hp2-2. Conclusion—Genotype-dependent impairment of hemoglobin clearance after intra-plaque hemorrhage is associated with increased oxidative, inflammatory, and angiogenic response in human diabetic atherosclerosis.

Intravascular ultrasound is an effective tool for predicting histopathology-confirmed evidence of adventitial injury following directional atherectomy for the treatment of peripheral artery disease

To the Editors: Directional atherectomy (DA) has emerged as a viable option for treatment of superficial femoral artery (SFA) occlusive disease. Despite excellent initial success, longterm patency with this therapy has had varying success. This variation in patency may be due to injury to the arterial wall during DA. Recently, we showed that histopathology evidence of deep injury to the adventitial layer of the vessel wall has a substantial negative effect on patency rates at 1 year. Continuing this work, we examined the relationship between intravascular ultrasound (IVUS)–identified external elastic lamina (EEL) disruption against the histopathology of the adventitia retrieved in the DA specimens. Of the 116 patients with TransAtlantic Inter-Society Consensus (TASC) A/B femoropopliteal lesions in our initial cohort, 108 had an IVUS examination after DA. IVUS imaging was performed by advancing the catheter to the most distal aspect of the lesion, and with data collected at 1 frame/s using a motorized pullback device set at 0.1 mm/s, raw sequential radiofrequency IVUS data were captured and transferred to a workstation for analysis. IVUS images were reconstructed utilizing IVUS lab software, and contours defining the internal elastic lamina (IEL) and EEL were identified automatically. A physician manually corrected the lumen and media-adventitial contours for each grayscale image. The IVUS definition of adventitial injury was disruption of the EEL and extension of the atherectomy cut past the EEL. Three board-certified interventional cardiologists independently reviewed all anonymized IVUS films to determine the presence or absence of EEL disruption; they had no knowledge of the histology outcomes. The IEL/EEL border was clearly identified, and the vessel structure at the site of atherectomy was comparatively examined to determine depth of disruption of vessel structures. Unanimous agreement of EEL border disturbance caused by the atherectomy device (Figure 1) was required for a “positive” EEL disruption assessment. Disagreements were classified as a negative for IVUSidentified adventitial injury. Investigator determination was then compared against histopathology findings of the atherectomy specimen as the reference gold standard. 647364 JETXXX10.1177/1526602816647364Journal of Endovascular TherapyKrishnan et al letter2016

Increased Myeloperoxidase Expression is Associated with Increasein Intra-Plaque Hemorrhage, Iron Content, Inflammation and Neovascularization in Diabetic Atherosclerosis: Implications for PlaqueProgression

Background: Myeloperoxidase (MPO), a heme peroxidase enzyme produced by macrophages, is a marker of oxidative stress associated with increased cardiovascular events in Diabetes Mellitus (DM). In this study we hypothesize that MPO protein and gene expression is associated with increased Intra-Plaque Hemorrhage (IPH), iron deposition, plaque inflammation and neovascularization in DM atheroma. Methods: Twenty-six human aortas with advanced plaques (14 DM vs.12 No-DM) were studied. MPO protein and gene expression were quantified with immunohistochemistry and RT-PCR respectively. IPH was evaluated using H&E stain. Plaque iron was scored using Perl’s stain and graded Inflammatory cells and neovessels were manually counted in parallel sections using with (CD68 and CD3), and (CD34) using immunohistochemistry method. Results: Total plaque MPO protein expression density (973.13 ± 28.32 vs. 356.24 ± 26.95; p = 0.0001) and MPO gene expression (0.00267 ± 0.0007 vs. 0.00033 ± 0.0001; p = 0.0001), IPH percentage (57.1% vs. 16.7 %; p= 0.04), iron grade (0.79 ± 0.21 vs. 0.25 ± 0.13; p = 0.05), inflammatory cell grade (1.71 ± 0.10 vs. 1.17 ± 0.11; p = 0.001) and total neovessel content (48.96 ± 4.68 vs. 21.54 ± 2.27; p = 0.0001) were significantly increased in DM plaques when compared to no-DM. Conclusion: Increased MPO protein and gene expression are associated with a parallel increase in IPH, iron grade, inflammation grade and neovessel content in DM. This suggests a possible role of MPO in enhancing the IPH, iron deposition; inflammation and neovascularization in high risk DM plaques may possibly due to oxidative stress.

Minimal Medial Injury After Orbital Atherectomy: An Intravascular Ultrasound Analysis.

Figure 1. Intravascular ultrasound images of 2 femoropopliteal lesions before (upper panels) and after (lower panels) treatment with the orbital atherectomy system (OAS). In A, there is a monolayer appearance (arrowheads in lower panel) of the arterial wall after OAS, indicating disappearing medial and intimal layers in the middle of a medial dissection (small arrows). In B, there is neither a new arterial wall monolayer nor a new medial dissection after OAS. Previous peripheral intervention studies have shown that excessive vessel injury in the tunica media is the primary cause of subsequent restenosis. The TRUTH study assessed the performance of the Orbital Atherectomy System (OAS; Cardiovascular Systems, Inc, St Paul, MN, USA) in the treatment of femoropopliteal lesions. In a post-hoc assessment of OAS-mediated vessel wall injury, intravascular ultrasound (IVUS) images from the TRUTH study were analyzed before and after OAS for signs of a monolayer appearance of the arterial wall, which indicates disappearing medial and intimal layers and external elastic lamina (Figure 1). One of the 23 preintervention images indicated medial injury vs only 2 cases in the post-OAS images, which suggests that OAS can treat calcific plaque while minimizing medial injury. These promising results suggest that additional studies should be completed to further understand the mechanism of action of OAS and its impact on the medial layer of the vessel being treated. This IVUS assessment method may allow the operating physician to detect medial injury intraprocedurally and alter treatment strategy for possible adjunctive antirestenosis therapy with drug-eluting technologies.

Relation of Internal Elastic Lamellar Layer Disruption to Neointimal Cellular Proliferation and Type III Collagen Deposition in Human Peripheral Artery Restenosis

Smooth muscle cell proliferation and extracellular matrix formation are responsible for disease progression in de novo and restenotic atherosclerosis. Internal elastic lamella (IEL) layer maintains the structural integrity of intima, and disruption of IEL may be associated with alterations in neointima, type III collagen deposition, and lesion progression in restenosis. Nineteen restenotic plaques (12 patients) procured during peripheral interventions were compared with 13 control plaques (12 patients) without restenosis. Hematoxylin & Eosin and elastic trichrome stains were used to measure length and percentage of IEL disruption, cellularity, and inflammation score. Type I and III collagens, smooth muscle cell (smc), fibroblast density, and nuclear proliferation (Ki67) percentage were evaluated by immunohistochemistry. IEL disruption percentage (28 ± 3.6 vs 6.1 ± 2.4; p = 0.0006), type III collagen content (0.33 ± 0.06 vs 0.17 ± 0.07; p = 0.0001), smc density (2014 ± 120 vs 923 ± 150; p = 0.0001), fibroblast density (2,282 ± 297 vs 906 ± 138; p = 0.0001), and Ki67 percentage (21.6 ± 2 vs 8.2 ± 0.65; p = 0.0001) were significantly increased in restenotic plaques compared to de novo plaques. Logistic regression analysis identified significant correlation between IEL disruption and neointimal smc density (r = 0.45; p = 0.01) and with type III collagen deposition (r = 0.61; p = 0.02) in restenosis. Increased IEL disruption may trigger cellular proliferation, altering collagen production, and enhancing restenotic neointima. In conclusion, understanding the pathologic and molecular basis of restenosis and meticulous-guided interventions oriented to minimize IEL damage may aid to reduce neointimal proliferation and the occurrence of restenosis.

Intravascular ultrasound guided directional atherectomy versus directional atherectomy guided by angiography for the treatment of femoropopliteal in-stent restenosis

Background: The aim of this study was to compare 1-year outcomes for patients with femoropopliteal in-stent restenosis using directional atherectomy guided by intravascular ultrasound (IVUS) versus directional atherectomy guided by angiography. Methods and results: This was a retrospective analysis for patients with femoropopliteal in-stent restenosis treated with IVUS-guided directional atherectomy versus directional atherectomy guided by angiography from a single center between March 2012 and February 2016. Clinically driven target lesion revascularization was the primary endpoint and was evaluated through medical chart review as well as phone call follow up. Conclusions: Directional atherectomy guided by IVUS reduces clinically driven target lesion revascularization for patients with femoropopliteal in-stent restenosis.