Determinants of target vessel failure in chronic total coronary occlusions after stent implantation The influence of collateral function and coronary hemodynamics

AbstractObjectivesThe goal of this study was to assess the influence of collateral function, coronary hemodynamics, and the angiographic result on the risk of target vessel failure (TVF) after recanalization of a chronic total coronary occlusion (CTO).BackgroundCollaterals may have an adverse effect on TVF.MethodsIn 111 consecutive patients, a CTO (duration >2 weeks) was successfully recanalized with stent implantation. Collateral function was assessed by intracoronary Doppler flow velocity and pressure recordings distal to the occlusion. Baseline collateral function was determined before the first balloon inflation, and recruitable collateral function after stenting during a balloon reocclusion. Finally, the coronary flow velocity reserve (CFVR) and the fractional flow reserve (FFR) were measured.ResultsAngiographic follow-up after 5 ± 1.4 months in 106 patients showed a reocclusion in 17% and a restenosis in 36%. The major determinants of TVF were the stent length (p < 0.01) and number of implanted stents (p < 0.01). No difference was observed in baseline or recruitable collateral function between patients with and without TVF; 52% of patients had a CFVR ≥2.0, and only 18% a CFVR ≥2.5 after percutaneous transluminal coronary angioplasty, but neither cutoff-value predicted TVF. A low FFR discriminated patients with reocclusion (0.81 ± 0.07 vs. 0.86 ± 0.08, p < 0.05) but not with restenosis (0.87 ± 0.06).ConclusionsThis study showed that there is no relation between a well-developed collateral supply and the risk of TVF in recanalized CTOs. This was rather determined by the stented segment length. There was also no adverse effect of the frequently observed impaired CFVR on TVF, whereas a low FFR was associated with a higher risk of reocclusion

Arginase Inhibition Reverses Monocrotaline-Induced Pulmonary Hypertension

Pulmonary hypertension (PH) is a heterogeneous disorder associated with a poor prognosis. Thus, the development of novel treatment strategies is of great interest. The enzyme arginase (Arg) is emerging as important player in PH development. The aim of the current study was to determine the expression of ArgI and ArgII as well as the effects of Arg inhibition in a rat model of PH. PH was induced in 35 Sprague–Dawley rats by monocrotaline (MCT, 60 mg/kg as single-dose). There were three experimental groups: sham-treated controls (control group, n = 11), MCT-induced PH (MCT group, n = 11) and MCT-induced PH treated with the Arg inhibitor Nω-hydroxy-nor-l-arginine (nor-NOHA; MCT/NorNoha group, n = 13). ArgI and ArgII expression was determined by immunohistochemistry and Western blot. Right ventricular systolic pressure (RVPsys) was measured and lung tissue remodeling was determined. Induction of PH resulted in an increase in RVPsys (81 ± 16 mmHg) compared to the control group (41 ± 15 mmHg, p = 0.002) accompanied by a significant elevation of histological sum-score (8.2 ± 2.4 in the MCT compared to 1.6 ± 1.6 in the control group, p < 0.001). Both, ArgI and ArgII were relevantly expressed in lung tissue and there was a significant increase in the MCT compared to the control group (p < 0.01). Arg inhibition resulted in a significant reduction of RVPsys to 52 ± 19 mmHg (p = 0.006) and histological sum-score to 5.8 ± 1.4 compared to the MCT group (p = 0.022). PH leads to increased expression of Arg. Arg inhibition leads to reduction of RVPsys and diminished lung tissue remodeling and therefore represents a potential treatment strategy in PH

Decrease in Circulating Dendritic Cell Precursors in Patients with Peripheral Artery Disease

Peripheral artery disease (PAD) is a common manifestation of atherosclerosis. Inflammation is important for initiation and progression of the disease. Dendritic cells (DCs) as antigen-presenting cells play an important role in the immune system. Therefore, we hypothesize that, in patients with PAD, DCPs might be reduced in blood due to their recruitment into the vascular wall and induce a proinflammatory response. The numbers of myeloid DCPs, plasmacytoid DCPs, and total DCPs were analyzed by flow cytometry in blood of patients with PAD (n=52) compared to controls (n=60). Femoralis plaques (n=12) of patients who underwent surgery were immunostained for CD209 and CD83 (mDCs) as well as CD304, CD123 (pDCs), and HLA-DR. In patients with PAD, a significant decrease in mDCPs, pDCPs, and tDCPs was observed. In immunostaining, markers indicative for mDCs (CD209: 16 versus 8 cells/0.1 mm2, P=0.02; CD83: 19 versus 5 cells/0.1 mm2, P=0.03) were significantly elevated in femoralis plaques compared to control vessels. We show for the first time that mDCPs, pDCPs, and tDCPs are significantly reduced in patients with PAD. Immunohistochemical analysis unraveled that the decrease in DCPs might be due to their recruitment into atherosclerotic plaques

Amplicon sequencing of colorectal cancer: variant calling in frozen and formalin-fixed samples.

Next generation sequencing (NGS) is an emerging technology becoming relevant for genotyping of clinical samples. Here, we assessed the stability of amplicon sequencing from formalin-fixed paraffin-embedded (FFPE) and paired frozen samples from colorectal cancer metastases with different analysis pipelines. 212 amplicon regions in 48 cancer related genes were sequenced with Illumina MiSeq using DNA isolated from resection specimens from 17 patients with colorectal cancer liver metastases. From ten of these patients, paired fresh frozen and routinely processed FFPE tissue was available for comparative study. Sample quality of FFPE tissues was determined by the amount of amplifiable DNA using qPCR, sequencing libraries were evaluated using Bioanalyzer. Three bioinformatic pipelines were compared for analysis of amplicon sequencing data. Selected hot spot mutations were reviewed using Sanger sequencing. In the sequenced samples from 16 patients, 29 non-synonymous coding mutations were identified in eleven genes. Most frequent were mutations in TP53 (10), APC (7), PIK3CA (3) and KRAS (2). A high concordance of FFPE and paired frozen tissue samples was observed in ten matched samples, revealing 21 identical mutation calls and only two mutations differing. Comparison of these results with two other commonly used variant calling tools, however, showed high discrepancies. Hence, amplicon sequencing can potentially be used to identify hot spot mutations in colorectal cancer metastases in frozen and FFPE tissue. However, remarkable differences exist among results of different variant calling tools, which are not only related to DNA sample quality. Our study highlights the need for standardization and benchmarking of variant calling pipelines, which will be required for translational and clinical applications

Paired frozen and FFPE samples of CRC liver metastases have a high concordance of mutations in hotspot cancer genes.

<p>(A) GATK Unified Genotyper variant calling pipeline was used to identify non-synonymous coding mutations in FFPE (green) and frozen samples (red). (B) Venn-Diagram of non-synonymous coding mutations identified in FFPE and frozen samples. (C) Representative images of reads mapped to the site of BRAF V600E mutation identified in FFPE but not in frozen tissue of patient 09, displayed with the Integrative Genomics Viewer. (D) Variant frequency of selected mutations and estimated tumor cell content analyzing FFPE samples.</p

KRAS mutations identified by sanger sequencing compared to deep amplicon sequencing analyzed with different variant calling tools.

<p>UG, Unified Genotyper pipeline; SAM, Samtools mpileup/Bcftools pipeline, SVC, Somatic Variant Caller; NA, not available</p><p>KRAS mutations identified by sanger sequencing compared to deep amplicon sequencing analyzed with different variant calling tools.</p