Evaluation Of Vascular Response Research Articles

Abstract 16601: Evaluation of Vascular Response After Balloon Angioplasty for In-Stent Restenosis Assessed by Optical Frequency Domain Imaging

Background and aim: The optimal balloon angioplasty (BA) procedure for in-stent restenosis (ISR) was not established. The aim of this study was to investigate vascular response after BA in ISR lesions using optimal frequency domain imaging (OFDI). Methods and results: This study consisted of 22 ISR lesions that were treated with BA. OFDI analysis were performed for 10mm longitudinal ISR segment including minimum lumen area before and after BA, furthermore morphology of ISR neointimal tissue and volumetric measurements were assessed. We analyzed at 1mm interval cross-sectional OFDI images of lesions before BA, and at every slices per each lesion, the neointimal tissue was divided into 2 morphologic patterns: homogeneous pattern and non-homogeneous pattern. Then, the neointimal tissue morphological characteristics of each lesion was expressed according to “homogeneous ratio”, defined as the number of homogeneous pattern slices divide by a total of slices. In volumetric OFDI measurements, lumen gain rate was calculated as (lumen volume (LV) after BA - LV before BA) / LV before BA, stent expansion rate as (stent volume (SV) after BA - SV before BA) / SV before BA and neointimal volume (NV) reduction rate as (NV before BA -NV after BA) / NV before BA. There was no correlation between homogeneous ratio and lumen gain ratio. There was positive correlation between homogeneous ratio and stent expansion ratio, and there was negative correlation between homogeneous ratio and neointimal volume reduction ratio (figure). Conclusions: OFDI assessment is useful to understand the vascular response by BA for ISR lesions. The mechanism of lumen gain in BA procedure for ISR lesions with homogeneous tissue is mainly obtained by stent expansion, whereas for lesions with non-homogeneous tissue is by neointimal tissue compression.

The murine dialysis fistula model exhibits a senescence phenotype: pathobiological mechanisms and therapeutic potential.

There is no therapy that promotes maturation and functionality of a dialysis arteriovenous fistula (AVF). The search for such therapies largely relies on evaluation of vascular responses and putative therapies in experimental AVFs. We studied an AVF in mice with chronic kidney disease (CKD). We demonstrate numerous stressors in the vein of the AVF-CKD group, including pathological shear, mitogenic, inflammatory, and hypoxia-reoxygenation stress. Because stress promotes premature senescence, we examined whether senescence is induced in the vein of the AVF-CKD model. We demonstrate a senescence phenotype in the AVF-CKD model, as indicated by increased expression of p16Ink4a, p21Cip1, and p53 and expected changes for certain senescence-associated microRNAs. RNA-sequencing analysis demonstrated differential expression of ~10,000 genes, including upregulation of proinflammatory and proliferative genes, in the vein of the AVF-CKD group. The vein in the AVF-CKD group exhibited telomere erosion and increased senescence-associated β-galactosidase activity and staining. Senescence was induced in the artery of the AVF-CKD group and in the vein of the AVF without CKD. Finally, given the rapidly rising clinical interest in senolytics, we provide proof of concept of senolytics as a therapeutic approach by demonstrating that senolytics decrease p16Ink4a expression in the AVF-CKD model. This study introduces a novel concept underlying the basis for maturational and functional failure in human dialysis AVFs and identifies a new target for senolytic therapy.

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A number of pathological events in humans such as solid tumour growth and metastasis have been found to be associated with angiogenesis, the formation of new blood vessels from pre-existing vasculature. A novel approach in cancer treatment consists of blocking or delaying the progression of neovascularisation to dysplastic cells in order to stop delivery of nutrients and oxygen. Thus, agents with antiangiogenic activity may be useful to treat cancer with potentially less systemic toxicity than conventional cytotoxic therapeutics. In this study we report the development and validation of a modified quantitative and objective in vivo chick embryo assay with Digital Image Analysis to screen compounds for antiangiogenic activity. The evaluation of vascular responses was optimised to less than one minute per sample in order to make this automatic method suitable for larger experimental series. Significant activity of the known antiangiogenic compounds thalidomide and captopril was determined, which resulted in approximately 50 % inhibition of the vessel area compared to the control. The stability and release of thalidomide and captopril within 48 h after application to the extraembryonic vessel system was monitored by HPLC analysis. In conclusion, this multiple target test system will be complementary to existing angiogenesis assays and may be useful to quantify the antiangiogenic activity of compounds.

Frequency-domain optical coherence tomography assessment of very late vascular response after carotid stent implantation

Intravascular optical coherence tomography is a high-resolution invasive imaging modality that allows the evaluation of vascular responses after stent implantation in a micron-scale level. We describe for the first time two patients with very late vascular response after carotid artery stenting that exhibit two different patterns of low-signal intensity (LSI), "ill-appearing" neointima: the first patient shows layered LSI neointima leading to stent restenosis, coupled with the presence of intraluminal thrombus, whereas the second patient demonstrates another pattern of non-restenotic LSI stent strut coverage, suggestive of lipid laden neointima (ie, "neoatherosclerosis"), recently associated with stent failure in coronary arteries.

Method Evaluation of In Situ Dissolution of Metallic Coronary Artery Stent

Evaluation of vascular responses to metallic stent implantation is essential in the setting of vascular disease. Study of the vascular response to stent implantation has been hampered by difficulties in sectioning metal and tissue without distortion of the tissue stent interface. Physical removal of the metal prior to processing frequently results in loss of arterial architecture, and current methods of embedding in resin have multiple drawbacks including expense, toxic or hazardous solution components, stent displacement and slow turnaround time.

TCT-502: Evaluation of Vascular Response to Drug Eluting Stents in a Porcine Coronary Artery Model: Comparison of Optical Coherence Tomography to Histology

TCT-502: Evaluation of Vascular Response to Drug Eluting Stents in a Porcine Coronary Artery Model: Comparison of Optical Coherence Tomography to Histology

Evaluation of vascular responses to cigarette smoking.

Evaluation of vascular responses to cigarette smoking.