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  • American Society of Hematology  (4)
  • Medicine  (4)
  • 1
    In: Blood, American Society of Hematology, Vol. 124, No. 21 ( 2014-12-06), p. 474-474
    Abstract: Background: Acquired deficiency of von Willebrand Factor (VWF) characterized by a quantitative loss of high molecular weight (HMW) multimers of VWF is associated with cardiovascular disorders such as aortic stenosis. It has been shown that HMW-multimers defect is usually corrected after surgical aortic valve replacement. However, the initial time course of loss/recovery of VWF HMW-multimers following acute changes in blood flow in-vivo has not yet been studied. We hypothesized that recovery of HMW-multimers could occur within minutes following correction of the underlying "high shear" condition and as such could be used to monitor acute changes in flow induced by cardiac interventions. We further investigated the potential underlying mechanisms. Methods: We investigated the time course of HMW-multimers loss/recovery in an animal model of instantaneous and reversible aortic stenosis (AS) specifically developed for that purpose. This model allowed the evaluation, in the same rabbit, of the dynamic time course of loss and recovery of HMW-multimers. We further investigated the time course of HMW-multimers loss/recovery and its related bedside whole blood assessment (PFA-100 analyzer) in 28 patients included in the WITAVI (Willebrand-TAVI) registry and undergoing 1) implantation of an axial-continuous-flow-LVAD (HeartMate-IIÒ, n=8) and 2) transcatheter aortic valve procedures, either BAV (n=10) or TAVI (n=10). VWF antigen (VWF:Ag) and VWF propeptide (VWFpp) levels were measured by ELISA. VWF multimeric analysis was performed as previously described in patients and newly developed for rabbits. PFA-CADP was assessed by platelet-function analyzer PFA-100® using ADP cartridges. Results: In the rabbit model, induction of aortic stenosis was associated with a HMW-multimers defect (normalized ratio = 0.74±0.07; p 〈 0.01 versus no stenosis). Partial recovery of HMW-multimers (0.89±0.12 versus AS baseline; p 〈 0.01) occurred within 5 minutes of stenosis reversion. Thirty minutes after reversion, a complete recovery of HMW-multimers was observed (0.98±0.10). In patients with AS (n=18) a VWF HMW-multimers defect was observed at baseline (0.50±0.18). Among patients with AS, those treated with TAVI experienced an acute decrease in shear stress (4.47±0.41 m.s-1 to 1.81±0.43 m.s-1, p 〈 0.0001, n=10) after treatment while those undergoing BAV alone experienced a modest improvement in shear stress conditions (4.47±0.25m.s-1 to 3.88±0.65m.s-1; p=0.03, n=8). In patients undergoing TAVI (n=10), similar to what was observed in the rabbit model, recovery of HMW-multimers defect was observed within minutes of valve implantation (p 〈 0.001, Table1). By contrast, in patients undergoing BAV (n=8) no recovery of HMW-multimers defect was observed (p=0.21,Table1). A potential role of the vascular endothelium in the HMW-multimers recovery was also evaluated by measuring the VWFpp levels during TAVI and BAV procedures. In TAVI procedures, VWFppsignificantly increased 5 minutes after valve implantation, and further after 30 and 180 minutes when compared to baseline. In BAV procedures, VWFpp did not increase significantly overtime. The time course of PFA-CADP time mimicked the recovery of HMW-multimers defect both in TAVI in patients, in whom a rapid correction of PFA-CADP was observed (p 〈 0.001, Table1), and BAV patients, in whom no correction was observed (p=0.69;Table1). Results are expressed as mean±SD, p values are for overall time course comparison (repeated Anova). Abstract 474. Table Transcatheter aortic valve implantion (TAVI, n=10) Balloon Aortic Valvuloplasty (BAV, n=8) T0 T5 T30 T180 p T0 T5 T30 T180 p HMW-multimers (ratio vs NP) 0.47(±0.14) 0.87(±0.24) 0.93(±0.17) 0.99(±0.16) 〈 0.001 0.52(±0.21) 0.58(±0.20) 0.66(±0.25) 0.63(±0.10) ns VWFpp (UI/dL) 168(±71) 195(±63) 215(±100) 429(±195) p 〈 0.01 256(±121) 234(±106) 290(±96) 275(±136) ns PFA-CT ADP (sec) 252(±68) 193(±51) 116(±40) 94(±26) 〈 0.001 201(±46) 212(±61) 204(±71) 219(±76) ns Conclusion: These results demonstrate that variations in the multimeric pattern of VWF are highly dynamic, occurring within minutes of changes in shear stress status. They further demonstrate that VWF multimeric pattern changes could be used in clinical practice as a tool to monitor the quality of the result of percutaneous aortic valve procedures procedures using a bedside analyzer. Disclosures No relevant conflicts of interest to declare.
    Type of Medium: Online Resource
    ISSN: 0006-4971 , 1528-0020
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    Language: English
    Publisher: American Society of Hematology
    Publication Date: 2014
    detail.hit.zdb_id: 1468538-3
    detail.hit.zdb_id: 80069-7
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  • 2
    In: Blood, American Society of Hematology, Vol. 134, No. Supplement_1 ( 2019-11-13), p. 3653-3653
    Abstract: Introduction: TAVI (Transcatheter Aortic Valve Implantation) represents the gold standard technique for the treatment of symptomatic severe aortic stenosis in patients at elevated surgical risk. This intervention is consistently associated with ischemic and haemorrhagic complications. In almost 60 % of the procedure, new cerebral ischemic lesions are observed on systematic magnetic resonance imaging (MRI) and it could speed up cognitive impairment. The lymphocyte-to-monocyte ratio (LMR), a new inflammatory marker, has been recently associated with ischemic burden in cardiovascular diseases. Objective: To study LMR changes before and after TAVI and investigate if LMR could be a predictive factor of new ischemic and haemorrhagic cerebral lesions after TAVI. Methods: Patients admitted for TAVI who accepted to be included in the METHYSTROKE study (NCT02972008) undergo cerebral MRI the day before the intervention and a second one 3 days after the procedure in order to observe the occurrence of ischemic and haemorrhagic cerebral lesions. LMR was gathered the day before (D0) and the day after TAVI (D1) from complete blood cell count. Results: A total of 124 patients were included in the present study (mean age was 82 ± 5.2 (SEM) years and 46% were male). Between D0 and D1, we observed a decrease in lymphocytes rate (mean (SD) : 1.25 (0.58) vs 1.14 (0.52) G/L, p=0.02) whereas the rate of monocytes raises (0.51 (0.27) vs 0.85 (0.42) G/L, p & lt;0.0001). Between D0 and D1, the LMR significantly falls (3.1 (0.24) vs 1.51 (0.75), p & lt;0.0001). New ischemic lesions occurred in 80 patients among the 124 (64.5%); LMR is significantly lower at D0 in patients who developed new cerebral ischemic lesions (2.30 (0.8) versus 2.97 (1.2), p=0.03). Each raise of pre-procedure LMR of a range of 0.1 increases the risk of post-operative cerebral ischemic lesions of 5.5 % (OR= 0.46, IC 95% 0.22-0.97, p=0.04). On the other side, 31 patients developed new haemorrhagic lesions on post-operative cerebral MRI (25%). Pre-procedure LMR was not significantly different among patients with and without haemorrhagic post-procedural cerebral complications (2.38 (0.93) vs 2.42 (1.1)). Conclusion: This study demonstrated that LMR decreases during TAVI and that pre-procedure LMR, a simple, readily available and low-cost biomarker, could be a predictive factor of post-TAVI new cerebral ischemic lesions. Disclosures No relevant conflicts of interest to declare.
    Type of Medium: Online Resource
    ISSN: 0006-4971 , 1528-0020
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    Language: English
    Publisher: American Society of Hematology
    Publication Date: 2019
    detail.hit.zdb_id: 1468538-3
    detail.hit.zdb_id: 80069-7
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  • 3
    In: Blood, American Society of Hematology, Vol. 141, No. 12 ( 2023-03-23), p. 1457-1468
    Abstract: von Willebrand factor (VWF) is a multimeric protein, the size of which is regulated via ADAMTS13-mediated proteolysis within the A2 domain. We aimed to isolate nanobodies distinguishing between proteolyzed and non-proteolyzed VWF, leading to the identification of a nanobody (designated KB-VWF-D3.1) targeting the A3 domain, the epitope of which overlaps the collagen-binding site. Although KB-VWF-D3.1 binds with similar efficiency to dimeric and multimeric derivatives of VWF, binding to VWF was lost upon proteolysis by ADAMTS13, suggesting that proteolysis in the A2 domain modulates exposure of its epitope in the A3 domain. We therefore used KB-VWF-D3.1 to monitor VWF degradation in plasma samples. Spiking experiments showed that a loss of 10% intact VWF could be detected using this nanobody. By comparing plasma from volunteers to that from congenital von Willebrand disease (VWD) patients, intact-VWF levels were significantly reduced for all VWD types, and most severely in VWD type 2A–group 2, in which mutations promote ADAMTS13-mediated proteolysis. Unexpectedly, we also observed increased proteolysis in some patients with VWD type 1 and VWD type 2M. A significant correlation (r = 0.51, P  & lt; .0001) between the relative amount of high–molecular weight multimers and levels of intact VWF was observed. Reduced levels of intact VWF were further found in plasmas from patients with severe aortic stenosis and patients receiving mechanical circulatory support. KB-VWF-D3.1 is thus a nanobody that detects changes in the exposure of its epitope within the collagen-binding site of the A3 domain. In view of its unique characteristics, it has the potential to be used as a diagnostic tool to investigate whether a loss of larger multimers is due to ADAMTS13-mediated proteolysis.
    Type of Medium: Online Resource
    ISSN: 0006-4971 , 1528-0020
    RVK:
    RVK:
    Language: English
    Publisher: American Society of Hematology
    Publication Date: 2023
    detail.hit.zdb_id: 1468538-3
    detail.hit.zdb_id: 80069-7
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  • 4
    In: Blood, American Society of Hematology, Vol. 114, No. 22 ( 2009-11-20), p. 1710-1710
    Abstract: Abstract 1710 Poster Board I-736 Introduction Treatment regimens for cancer are typically based on cytotoxic chemotherapy, which is poorly tolerated. There is an unmet medical need for new therapies that retain efficacy, but combine this with an improved safety and tolerability profile. Vorinostat is a histone deacetylase (HDAC) inhibitor, approved in the United States for the treatment of cutaneous manifestations of cutaneous T-cell lymphoma (CTCL) in patients who have progressive, persistent, or recurrent disease on or following 2 systemic therapies. Vorinostat is also being investigated as a treatment for various other solid and hematologic malignancies, in which HDACs are further implicated as key regulators of transcription. Herein we present an overview of the safety and tolerability profile of vorinostat, gathered from prior clinical experience. Methods Safety and tolerability data, including adverse events (AEs), QTc interval data and incidence of thromboembolic events (TEE), were collated from patients who received vorinostat, administered as monotherapy or in combination therapy for solid or hematologic malignancies. Results (adverse events) In Phase I and II clinical trials, 498 patients who received vorinostat were analyzed. A total of 341 patients received vorinostat monotherapy (107 with CTCL, 105 other hematologic malignancies, 129 solid tumors) and the most common drug-related AEs in this group were: fatigue (61.9%), nausea (55.7%), diarrhea (49.3%), anorexia (48.1%), and vomiting (32.8%); Grade 3/4 AEs included fatigue (12.0%) and thrombocytopenia (10.6%), and 3 drug-related deaths (ischemic stroke, tumor hemorrhage, unspecified) occurred. Thirty-eight patients (11.1%) discontinued due to drug-related AEs, 71 patients (20.8%) required dose modifications, and 1 patient (0.3%) discontinued due to Grade 2 chest pain. The remaining 157 patients received vorinostat combination therapy (with pemetrexed/cisplatin for advanced cancer [n=46] , bortezomib for multiple myeloma [n=34], bexarotene for CTCL [n=23] , and erlotinib [n=30], gemcitabine/platin [n=21] or carboplatin/paclitaxel [n=3] for non-small-cell lung cancer). The most common drug-related AEs in this group were: nausea (48.4%), diarrhea (40.8%), fatigue (34.4%), and vomiting (31.2%); the most common Grade 3/4 AE was fatigue (13.4%), and 1 drug-related death (hemoptysis) occurred. Thirty-one patients (19.7%) discontinued due to drug-related AEs and 27 patients (17.2%) required dose modifications. Results (QTcF interval) A trial of 24 patients with advanced cancer was undertaken for rigorous assessment of QTcF interval. In this trial, a single supratherapeutic 800 mg dose of vorinostat did not prolong QTcF interval (monitored over 24 hours). The upper limit of the 90% confidence interval for the placebo-adjusted mean change-from-baseline of vorinostat was 〈 10 msec at every timepoint, no patient had a QTcF change-from-baseline value 〉 30 msec, and 1 patient had a QTcF interval 〉 450 msec (after both vorinostat and placebo administration). The most common drug-related AE in this trial was nausea. There were no serious clinical or laboratory AEs, no discontinuations due to an AE and no patients experienced a cardiac-related AE. Results (incidence of TEE) A review of vorinostat clinical trials, published literature and post-marketing surveillance reports was conducted by a committee of independent academic experts to determine the incidence of TEE in cancer patients who had received vorinostat. In 〉 1845 patients reviewed through November 3, 2008, 107 patients ( 〈 5.8%) reported TEE as a serious AE (SAE), 47 ( 〈 2.6%) of which were recorded as being related to vorinostat, and 4/47 ( 〈 0.3%) TEE SAEs were fatal. Conclusions In this review, the majority of observed AEs were 'Grade 2, there was no observed prolongation of the QTcF interval, and the incidence of TEE with vorinostat was similar to reported rates of TEE in advanced cancer patients. Vorinostat is generally well tolerated when administered as monotherapy or in a combination regimen in cancer patients. Disclosures Siegel: Millennium: Honoraria, Membership on an entity's Board of Directors or advisory committees, Speakers Bureau; Celegne: Honoraria, Membership on an entity's Board of Directors or advisory committees, Speakers Bureau. Rubin:Merck: Employment, Equity Ownership. Iwamoto:Merck: Employment, Equity Ownership. Hussein:Celgene: Employment. Belani:Merck: Consultancy. Hardwick:Merck: Employment, Equity Ownership. Rizvi:Merck: Employment, Equity Ownership.
    Type of Medium: Online Resource
    ISSN: 0006-4971 , 1528-0020
    RVK:
    RVK:
    Language: English
    Publisher: American Society of Hematology
    Publication Date: 2009
    detail.hit.zdb_id: 1468538-3
    detail.hit.zdb_id: 80069-7
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