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1.
Breast Cancer ; 2024 Apr 18.
Artigo em Inglês | MEDLINE | ID: mdl-38635135

RESUMO

PURPOSE: To improve the quality of care for patients with breast cancer, an analysis of the health-care pathway, considering feedback from both health-care practitioners (HCPs) and patients, is needed. METHODS: Between 2020 and 2022, we conducted a survey at French breast cancer centers and analyzed information from questionnaires completed by HCPs and patients. We collected information on center organization, diagnostic processes, treatment decisions and modalities, supportive care, patient advocacy groups, and work issues. RESULTS: Twenty-three breast cancer centers were included and questionnaires completed by 247 HCPs and 249 patients were analyzed. The centers closely followed the legal French framework for cancer treatments, which includes formal diagnostic announcements, multidisciplinary tumor boards, personalized treatment summaries, and supportive care access. HCPs and patients were satisfied with the time to diagnosis (≤ 2 weeks as evaluated by 75% of patients), time to surgery (mean 61 days), time between surgery and chemotherapy (mean 47 days), and time between surgery and radiotherapy (mean 81 days). Fertility preservation counseling for women under 40 years of age was systematically offered by 67% of the HCPs. The majority (67%) of the patients indicated that they had received a personalized treatment summary; the topics discussed included treatments (92%), tumor characteristics (84%), care pathways (79%), supportive care (52%), and breast reconstruction (33%). Among HCPs, 44% stated that reconstructive surgery was offered to all eligible patients and 57% and 45% indicated coordination between centers and primary care physicians for adverse effects management and access to supportive care should be improved, for chemotherapy and radiotherapy, respectively. Regarding patient advocacy groups, 34% of HCPs did not know whether patients had contact and only 23% of patients declared that they had such contact. For one-third of working patients, work issues were not discussed. Twenty-eight percent of patients claimed that they had faced difficulties for supportive care access. Among HCPs, 13% stated that a formal personalized survivorship treatment program was administered to almost all patients and 37% almost never introduced the program to their patients. Compliance to oral treatments was considered very good for 75-100% of patients by 62% of HCPs. CONCLUSIONS: This study provides an updated analysis of breast cancer care pathways in France. Overall, the initial processes of diagnosis, announcement, and treatment were swift and were in agreement with the best care standards. No barriers to accessing care were identified. Based on the study findings, we proposed several strategies to improve the quality of care for patients in supportive care, coordination with primary care physicians, reconstructive surgery, and fertility preservation access.

2.
Mol Clin Oncol ; 19(1): 51, 2023 Jul.
Artigo em Inglês | MEDLINE | ID: mdl-37323248

RESUMO

Nuclear medicine is an essential part of prostate cancer management concerning initial staging, patient follow-up and even therapy. Prostate-specific membrane antigen (PSMA) is a glutamate carboxypeptidase II transmembrane glycoprotein expressed by 80% of prostatic cells. The interest in this protein is due to its specificity for prostatic tissue. The use of 68GaPSMA PET/CT in the context of disease staging is thus well-established and recommended, especially for high-risk disease with metastases and lymph node involvement. However, the risk of false positives raises questions regarding its place in the management of patients with prostate cancer. The present study aimed to determine the use of PET-PSMA in the care of patients with prostate cancer but also to assess its limits of use.

3.
Breast Cancer ; 30(2): 315-328, 2023 Mar.
Artigo em Inglês | MEDLINE | ID: mdl-36602669

RESUMO

BACKGROUND: The objective of the CHEOPS trial was to assess the benefit of adding aromatase inhibitor (AI) to metronomic chemotherapy, oral vinorelbine, 50 mg, three times a week for pre-treated, HR + /HER2- metastatic breast cancer patients. METHODS: In this multicentric phase II study, patients had to have progressed on AI and one or two lines of chemotherapy. They were randomized between oral vinorelbine (Arm A) and oral vinorelbine with non-steroidal AI (Arm B). RESULTS: 121 patients were included, 61 patients in Arm A and 60 patients in Arm B. The median age was 68 years. 109 patients had visceral metastases. They all had previously received an AI. The study had been prematurely stopped following the third death due to febrile neutropenia. Median PFS trend was found to be different with 2.3 months and 3.7 months in Arm A and Arm B, respectively (HR 0.73, 95%CI 0.50-1.06, p value = 0.0929). No statistical difference was shown in OS and better tumor response. 56 serious adverse events corresponding to 25 patients (21%) were reported (respectively, 12 (20%) versus 13 (22%) for arms A and B) (NS). CONCLUSION: The addition of AI to oral vinorelbine over oral vinorelbine alone in aromatase inhibitor-resistant metastatic breast cancer was associated with a non-significant improvement of PFS. Several unexpected serious adverse events were reported. Metronomic oral vinorelbine schedule, at 50 mg three times a week, requires close biological monitoring. The question of hormonal treatment and chemotherapy combination remains open.


Assuntos
Neoplasias da Mama , Humanos , Idoso , Feminino , Vinorelbina/uso terapêutico , Neoplasias da Mama/patologia , Inibidores da Aromatase/uso terapêutico , Protocolos de Quimioterapia Combinada Antineoplásica/efeitos adversos , Vimblastina/efeitos adversos , Metástase Neoplásica , Resultado do Tratamento
4.
Anticancer Res ; 43(2): 653-662, 2023 Feb.
Artigo em Inglês | MEDLINE | ID: mdl-36697069

RESUMO

BACKGROUND/AIM: Olaparib was approved in 2014 by the European Medicines Agency (EMA) as maintenance treatment for patients with breast cancer gene (BRCA)-mutated platinum-sensitive relapsed high-grade epithelial ovarian cancer (EOC) following the results of the Study 19. We present the results of a national real-world study on the effectiveness of olaparib in relapsed BRCA-mutated EOC patients. PATIENTS AND METHODS: Patients with EOC, peritoneal, and/or fallopian-tube cancer treated with olaparib in a French Center between May 2014 and March 2017 were included. The primary end-point of the study was progression-free survival. RESULTS: Of the 128 patients analyzed, 89 were treated according to the EMA label. The median progression-free survival was 17.0 months. The most common treatment-related toxicity was fatigue. Treatment-related myelodysplastic syndrome (n=5) and a second cancer (n=1) were diagnosed. CONCLUSION: In this real-life setting, olaparib confirmed its efficacy and safety profile, as previously shown in clinical trials.


Assuntos
Antineoplásicos , Neoplasias Ovarianas , Humanos , Feminino , Carcinoma Epitelial do Ovário/tratamento farmacológico , Carcinoma Epitelial do Ovário/genética , Antineoplásicos/uso terapêutico , Neoplasias Ovarianas/tratamento farmacológico , Neoplasias Ovarianas/genética , Estudos de Coortes , Ftalazinas/efeitos adversos , Recidiva Local de Neoplasia/tratamento farmacológico , Recidiva Local de Neoplasia/genética
5.
Breast ; 61: 84-90, 2022 Feb.
Artigo em Inglês | MEDLINE | ID: mdl-34923226

RESUMO

BACKGROUND: Sarcopenia has emerged as an important parameter to predict outcomes and treatment toxicity. However, limited data are available to assess sarcopenia prevalence in metastatic breast cancer and to evaluate its management. METHODS: The SCAN study was a cross-sectional multicenter French study that aimed to estimate sarcopenia prevalence in a real-life sample of metastatic cancer patients. Sarcopenia was identified by low muscle mass (estimated from the skeletal muscle index at the third lumbar, via computed tomography) and low muscle strength (defined by handgrip strength). Three populations were distinguished based on EWGSOP criteria: a sarcopenic group with low muscle mass AND strength, a pre-sarcopenic group with low muscle mass OR strength and a normal group with high muscle mass AND strength. RESULTS: Among 766 included patients, 139 patients with breast cancer and median age of 61.2 years (29.9-97.8 years) were evaluable; 29.5% were sarcopenic and 41.0% were pre-sarcopenic. Sarcopenic patients were older (P < 0.01), had a worse PS-score (P < 0.05), and a higher number of metastatic sites (P < 0.01), the majority being hepatic and bone. A moderate agreement between the oncologist's diagnosis and sarcopenia evaluation by muscle mass and strength was recognized (Cohen's kappa = 0.45). No associations were found between sarcopenia and adverse event occurrence in the 12 patients for whom these were reported. Sarcopenic patients were underdiagnosed and nutritional care and physical activity were less proposed. CONCLUSION: It is necessary to evaluate sarcopenia due to its impact on patient prognosis, and its utility in guiding patient management in metastatic breast cancer.


Assuntos
Neoplasias da Mama , Sarcopenia , Neoplasias da Mama/complicações , Neoplasias da Mama/patologia , Estudos Transversais , Feminino , Força da Mão , Humanos , Pessoa de Meia-Idade , Força Muscular , Músculo Esquelético/patologia , Sarcopenia/epidemiologia , Sarcopenia/etiologia , Sarcopenia/patologia
6.
Artigo em Inglês | MEDLINE | ID: mdl-34706865

RESUMO

OBJECTIVES: Febrile neutropenia (FN) commonly occurs during cancer chemotherapy. Prophylaxis with granulocyte colony-stimulating factors (G-CSFs) is known to reduce the severity and incidence of FN and infections in patients with cancer. Despite the proven efficacy, G-CSFs are not always prescribed as recommended. We performed a discrete-choice experiment (DCE) to determine what factors drive the physician preference for FN prophylaxis in patients with cancer undergoing chemotherapy. METHODS: Attributes for the DCE were selected based on literature search and on expert focus group discussions and comprised pain at the injection site, presence of bone pain, associated fever/influenza syndrome, efficacy of prophylaxis, biosimilar availability, number of injections per chemotherapy cycle and cost. Oncologists, in a national database, were solicited to participate in an online DCE. The study collected the responses to the choice scenarios, the oncologist characteristics and their usual prescriptions of G-CSFs in the context of breast, lungs and gastrointestinal cancers. RESULTS: Overall, the responses from 205 physicians were analysed. The physicians were mainly male (61%), with ≤20 years of experience (76%) and working only in public hospitals (73%). The physicians prescribe G-CSF primary prophylaxis for 32% of patients: filgrastim in 46% and pegfilgrastim in 54%. The choice of G-CSF for primary and secondary prophylaxis was driven by cost and number of injections. Biosimilars were well accepted. CONCLUSION: Cost and convenience of G-CSF drive the physician decision to prescribe or not G-CSF for primary and secondary FN prophylaxes. It is important that these results be incorporated in the optimisation of G-CSF prescription in the clinical setting.

7.
Oncologist ; 26(10): e1870-e1879, 2021 10.
Artigo em Inglês | MEDLINE | ID: mdl-34216177

RESUMO

BACKGROUND: Neurokinin (NK) 1 receptor antagonists (RAs), administered in combination with a 5-hydroxytryptamine-3 (5-HT3 ) RA and dexamethasone (DEX), have demonstrated clear improvements in chemotherapy-induced nausea and vomiting (CINV) prevention over a 5-HT3 RA plus DEX. However, studies comparing the NK1 RAs in the class are lacking. A fixed combination of a highly selective NK1 RA, netupitant, and the 5-HT3 RA, palonosetron (NEPA), simultaneously targets two critical antiemetic pathways, thereby offering a simple convenient antiemetic with long-lasting protection from CINV. This study is the first head-to-head NK1 RA comparative study in patients receiving anthracycline cyclophosphamide (AC) and non-AC moderately emetogenic chemotherapy (MEC). MATERIALS AND METHODS: This was a pragmatic, multicenter, randomized, single-cycle, open-label, prospective study designed to demonstrate noninferiority of single-dose NEPA to a 3-day aprepitant regimen in preventing CINV in chemotherapy-naive patients receiving AC/non-AC MEC in a real-life setting. The primary efficacy endpoint was complete response (no emesis/no rescue) during the overall (0-120 hour) phase. Noninferiority was achieved if the lower limit of the 95% confidence interval (CI) of the difference between NEPA and the aprepitant group was greater than the noninferiority margin set at -10%. RESULTS: Noninferiority of NEPA versus aprepitant was demonstrated (risk difference 9.2%; 95% CI, -2.3% to 20.7%); the overall complete response rate was numerically higher for NEPA (64.9%) than aprepitant (54.1%). Secondary endpoints also revealed numerically higher rates for NEPA than aprepitant. CONCLUSION: This pragmatic study in patients with cancer receiving AC and non-AC MEC revealed that a single dose of oral NEPA plus DEX was at least as effective as a 3-day aprepitant regimen, with indication of a potential efficacy benefit for NEPA. IMPLICATIONS FOR PRACTICE: In the absence of comparative neurokinin 1 (NK1 ) receptor antagonist (RA) studies, guideline committees and clinicians consider NK1 RA agents to be interchangeable and equivalent. This is the first head-to-head study comparing one NK1 RA (oral netupitant/palonosetron [NEPA]) versus another (aprepitant) in patients receiving anthracycline cyclophosphamide (AC) and non-AC moderately emetogenic chemotherapy. Noninferiority of NEPA versus the aprepitant regimen was demonstrated; the overall complete response (no emesis and no rescue use) rate was numerically higher for NEPA (65%) than aprepitant (54%). As a single-dose combination antiemetic, NEPA not only simplifies dosing but may offer a potential efficacy benefit over the current standard-of-care.


Assuntos
Antieméticos , Antineoplásicos , Antibióticos Antineoplásicos/uso terapêutico , Antieméticos/uso terapêutico , Antineoplásicos/efeitos adversos , Aprepitanto , Método Duplo-Cego , Humanos , Isoquinolinas/uso terapêutico , Náusea/induzido quimicamente , Náusea/tratamento farmacológico , Náusea/prevenção & controle , Palonossetrom/uso terapêutico , Estudos Prospectivos , Quinuclidinas/uso terapêutico , Vômito/induzido quimicamente , Vômito/tratamento farmacológico , Vômito/prevenção & controle
8.
Eur J Cancer Care (Engl) ; 29(6): e13299, 2020 Nov.
Artigo em Inglês | MEDLINE | ID: mdl-32885521

RESUMO

OBJECTIVE: Over recent decades, supportive care and patient quality of life, advocated by dedicated guidelines, have become a core focus of the concept of integrative medicine. The Calista 2 survey was conducted in France between September 2016 and October 2017 among oncologists and their patients being treated for early breast cancer, adjuvant colorectal cancer or advanced lung cancer. The present analysis sought to ascertain, understand and rank the expectations of cancer patients with regard to supportive care. METHODS: Data were collected from 467 questionnaires from patients recruited by 82 oncologists. Inclusion criteria were patients already on treatment for breast cancer, colorectal cancer or lung cancer. Most supportive care facilities were available at the point of care. RESULTS: Physicians were mainly seen to offer management of adverse events (81%), and pain (72%), psychological support (56%), and advice on diet/nutrition (49%). Patient uptake of supportive care related essentially to management of adverse events (72%) and pain (61%), diet/nutrition (34%), and self-image improvement techniques (31%). The main unmet needs voiced by patients were information on complementary medicines (28%), management of fatigue (27%), and relaxation techniques (24%). CONCLUSION: Supportive care was essentially seen to satisfy patient requirements with regard to the management of adverse events and pain. However, patients highlighted the need for a wider access to fatigue management and information on complementary medicine and relaxation techniques.


Assuntos
Neoplasias da Mama , Oncologistas , Neoplasias da Mama/terapia , Fadiga , Feminino , Humanos , Qualidade de Vida , Inquéritos e Questionários
9.
J Psychosoc Oncol ; 37(1): 50-68, 2019.
Artigo em Inglês | MEDLINE | ID: mdl-30295567

RESUMO

PURPOSE: This study aimed to compare the self-reported perceptions of the repercussions of the disease and its treatments and emotional distress in young women with breast cancer and their partners. DESIGN: Cross-sectional study using self-reported questionnaires. SAMPLE: 491 couples in which women were aged <45 years when diagnosed with non-metastatic breast cancer in four different groups of treatment: during chemotherapy with or without Trastuzumab; under Trastuzumab with or without hormone therapy; during hormone therapy; and during the follow-up period. METHODS: Patients and partners completed a questionnaire assessing their self-reported perceptions of the disease and treatments (Patient YW-BCI and Partner YW-BCI for the partners) and their emotional distress (CESD; STAI). FINDINGS: Patients reported more difficulties than partners in the management of child(ren) and everyday life, body image and sexuality, negative affectivity about the disease and apprehension about the future, career management, and finances. While the difficulties were generally more marked in the chemotherapy and Trastuzumab groups than in the hormone therapy and follow-up groups, the negative affectivity about the disease and apprehension about the future was high in all four groups, especially in patients. The partners reported more difficulties in sharing with close relatives, and even more in those groups reflecting the latest treatment phases. No difference appeared between patients and partners in couple cohesion and deterioration of relationships with relatives. Partners were less anxious than patients but as depressed as them. CONCLUSIONS: Difficulties of patients and partners seem particularly severe in the early care pathway, maybe reflecting better adjustment in women under surveillance and their partners. A longitudinal study will substantiate this finding and enable a better identification of some explanatory processes of these differences and similarities in the daily self-reported repercussions of the disease throughout the cancer care pathway. Implications for psychosocial oncology: It seems important to support young women with breast cancer and their partners, as our results evidence distress in both and differences according to the type of treatment the woman is currently receiving. Healthcare providers need consistent methods to identify and respond to couples' distress and reduce significant disparities in support.


Assuntos
Atitude Frente a Saúde , Neoplasias da Mama/psicologia , Parceiros Sexuais/psicologia , Adulto , Neoplasias da Mama/terapia , Estudos Transversais , Feminino , Humanos , Masculino , Pessoa de Meia-Idade , Autorrelato
11.
Presse Med ; 47(1): 19-33, 2018 Jan.
Artigo em Francês | MEDLINE | ID: mdl-29275972

RESUMO

Antiresorptives and antiangiogenics are treatments that have proven effective in oncology and the treatment of osteoporosis and they are increasingly prescribed. The care of these patients requires collaboration between the prescriber and the oral health professional to establish an optimized treatment plan. Therapeutic education of the patient is essential for him to understand the issues of good oral health and the adverse effects that can be caused by these treatments. The management is essentially based on the individual benefit/risk balance resulting from the general, local and inherent of the molecule risk factors. Management of drug-related osteonecrosis of the jaw should be as early as possible.


Assuntos
Inibidores da Angiogênese/efeitos adversos , Conservadores da Densidade Óssea/efeitos adversos , Difosfonatos/efeitos adversos , Doenças Maxilomandibulares/induzido quimicamente , Osteonecrose/induzido quimicamente , Osteonecrose da Arcada Osseodentária Associada a Difosfonatos/etiologia , Osteonecrose da Arcada Osseodentária Associada a Difosfonatos/patologia , Osteonecrose da Arcada Osseodentária Associada a Difosfonatos/prevenção & controle , Osteonecrose da Arcada Osseodentária Associada a Difosfonatos/cirurgia , Conservadores da Densidade Óssea/uso terapêutico , Reabsorção Óssea/tratamento farmacológico , Assistência Odontológica/métodos , Difosfonatos/história , Difosfonatos/uso terapêutico , História do Século XIX , História do Século XX , Humanos , Doenças Maxilomandibulares/diagnóstico por imagem , Doenças Maxilomandibulares/história , Doenças Maxilomandibulares/prevenção & controle , Neoplasias/tratamento farmacológico , Doenças Profissionais/história , Procedimentos Cirúrgicos Bucais/efeitos adversos , Procedimentos Cirúrgicos Bucais/métodos , Osteonecrose/diagnóstico por imagem , Osteonecrose/prevenção & controle , Osteoporose/tratamento farmacológico , Fósforo/toxicidade , Complicações Pós-Operatórias/induzido quimicamente , Extração Dentária/efeitos adversos
12.
Future Oncol ; 13(29): 2667-2680, 2017 Dec.
Artigo em Inglês | MEDLINE | ID: mdl-29191056

RESUMO

AIM: Evaluate the influence of emotional distress of young women with breast cancer and their spouses on their daily subjective experience of the disease, through application of the Actor-Partner Interdependence Model. PATIENTS & METHODS: A total of 112 women under 45 years of age were diagnosed with nonmetastatic breast cancer and their spouses answered self-reported measures of anxiety, depression and subjective experience of the disease and its treatment. RESULTS: The patient's emotional distress influenced more the subjective experience of her spouse than the spouse's emotional distress influenced the patient. The spouse's difficulties depended as much on his own distress level as on the patient's distress level. CONCLUSION: These data confirm the importance of implementing couple-focused interventions.


Assuntos
Neoplasias da Mama/epidemiologia , Neoplasias da Mama/psicologia , Emoções , Cônjuges/psicologia , Estresse Psicológico , Adulto , Ansiedade/epidemiologia , Ansiedade/etiologia , Depressão/epidemiologia , Depressão/etiologia , Feminino , Humanos , Masculino , Pessoa de Meia-Idade , Adulto Jovem
13.
Macromolecules ; 50(1): 182-191, 2017 Jan 10.
Artigo em Inglês | MEDLINE | ID: mdl-31007283

RESUMO

RAFT-synthesized polymers are typically colored and malodorous due to the presence of the sulfur-based RAFT end-group(s). In principle, RAFT end-groups can be removed by treating molecularly dissolved copolymer chains with excess free radical initiators, amines, or oxidants. Herein we report a convenient method for the removal of RAFT end-groups from aqueous dispersions of diblock copolymer nano-objects using H2O2. This oxidant is relatively cheap, has minimal impact on the copolymer morphology, and produces benign side products that can be readily removed via dialysis. We investigate the efficiency of end-group removal for various diblock copolymer nano-objects prepared with either dithiobenzoate- or trithiocarbonate-based RAFT chain transfer agents. The advantage of using UV GPC rather than UV spectroscopy is demonstrated for assessing both the kinetics and extent of end-group removal.

14.
Anticancer Res ; 33(1): 301-7, 2013 Jan.
Artigo em Inglês | MEDLINE | ID: mdl-23267161

RESUMO

AIM: To carry out a prospective, multicenter and observational study describing prophylactic strategies [cycle delay, dose-reduction, (G-CSF) prescription] to prevent recurrence of neutropenic events (NE) in patients with solid tumors, and identify potential predictive factors of NE recurrence. PATIENTS AND METHODS: Patients ≥18 years old with an NE in a previous chemotherapy cycle (cycle A) without G-CSF support, followed for four cycles (B to E) were included in the study. NE was defined as any neutropenia grade 1-4, febrile or not, which impacted on subsequent chemotherapy cycles (cycle delay, or reduction, or prophylactic G-CSF). RESULTS: Data of 548 patients were analyzed, 378 (69%) were female, with a mean (SD) age of 61.7 (12.3) years. WHO PS: 0-1: 88.3%, incidence of breast cancer: 40%, metastatic disease: 53.3%. Following the first NE episode, 44.5% of patients had cycle delay, 22.3% dose reduction and 466 (85%) received prophylactic G-CSF. NE recurrence rates were: 21.2% at cycle B, 18.6% at cycle C, 11.5% at cycle D and 12.9% at cycle E. G-CSF support (hazard ratio: 0.32, 0.24-0.43, p<0.001) was associated with lower NE recurrence. Pegfilgrastim seemed to offer the highest protection (hazard ratio; HR=0.23, 95% CI: 0.16-0.32; p<0.001). CONCLUSION: Secondary G-CSF prophylaxis has significant efficacy in reducing the incidence of NE and should be considered as a valuable option.


Assuntos
Antineoplásicos/efeitos adversos , Fator Estimulador de Colônias de Granulócitos/administração & dosagem , Neoplasias , Neutropenia/prevenção & controle , Adolescente , Adulto , Idoso , Idoso de 80 Anos ou mais , Humanos , Pessoa de Meia-Idade , Neoplasias/complicações , Neoplasias/tratamento farmacológico , Neutropenia/induzido quimicamente , Estudos Prospectivos , Prevenção Secundária
15.
Ann Biomed Eng ; 40(7): 1468-85, 2012 Jul.
Artigo em Inglês | MEDLINE | ID: mdl-22215278

RESUMO

Previous experimental and numerical blood studies have shown that high shear stress levels, long exposure times to these shear stresses, and flow recirculation promote thromboembolism. Artificial heart valves, in particular bileaflet mechanical heart valves (BMHVs), are prone to developing thromboembolic complications. These complications often form at the hinge regions of BMHVs and the associated geometry has been shown to affect the local flow dynamics and the associated thrombus formation. However, to date no study has focused on simulating the motion of realistically modeled blood elements within the hinge region to numerically estimate the hinge-related blood damage. Consequently, this study aims at (a) simulating the motion of realistically modeled platelets during the leakage (mid-diastole) phase in different BMHV hinge designs placed in the aortic position and (b) quantitatively comparing the blood damage associated with different designs. Three designs are investigated to assess the effects of hinge geometry and dimensions: a 23 mm St. Jude Medical Regent™ valve hinge with two different gap distances between the leaflet ear and hinge recess; and a 23 mm CarboMedics (CM) aortic valve hinge. The recently developed lattice-Boltzmann method with external boundary force method is used to simulate the hinge flow and capture the dynamics and surface shear stresses of individual platelets. A blood damage index (BDI) value is then estimated based on a linear shear stress-exposure time BDI model. The velocity boundary conditions are obtained from previous 3D large-scale simulations of the hinge flow fields. The trajectories of the blood elements in the hinge region are found to be qualitatively similar for all three hinges, but the shear stresses experienced by individual platelets are higher for the CM hinge design, leading to a higher BDI. The results of this study are also shown to be in good agreement with previous studies, thus validating the numerical method for future research in BMHV flows. This study provides a general numerical tool to optimize the hinge design based on both hemodynamic and thromboembolic performance.


Assuntos
Plaquetas/metabolismo , Coração Artificial/efeitos adversos , Modelos Cardiovasculares , Estresse Fisiológico , Tromboembolia/etiologia , Tromboembolia/metabolismo , Velocidade do Fluxo Sanguíneo , Humanos
16.
Ann Biomed Eng ; 38(11): 3295-310, 2010 Nov.
Artigo em Inglês | MEDLINE | ID: mdl-20571852

RESUMO

Thromboembolic complications (TECs) of bileaflet mechanical heart valves (BMHVs) are believed to be due to the nonphysiologic mechanical stresses imposed on blood elements by the hinge flows. Relating hinge flow features to design features is, therefore, essential to ultimately design BMHVs with lower TEC rates. This study aims at simulating the pulsatile three-dimensional hinge flows of three BMHVs and estimating the TEC potential associated with each hinge design. Hinge geometries are constructed from micro-computed tomography scans of BMHVs. Simulations are conducted using a Cartesian sharp-interface immersed-boundary methodology combined with a second-order accurate fractional-step method. Leaflet motion and flow boundary conditions are extracted from fluid-structure-interaction simulations of BMHV bulk flow. The numerical results are analyzed using a particle-tracking approach coupled with existing blood damage models. The gap width and, more importantly, the shape of the recess and leaflet are found to impact the flow distribution and TEC potential. Smooth, streamlined surfaces appear to be more favorable than sharp corners or sudden shape transitions. The developed framework will enable pragmatic and cost-efficient preclinical evaluation of BMHV prototypes prior to valve manufacturing. Application to a wide range of hinges with varying design parameters will eventually help in determining the optimal hinge design.


Assuntos
Próteses Valvulares Cardíacas , Valvas Cardíacas/fisiologia , Modelos Cardiovasculares , Animais , Valvas Cardíacas/anatomia & histologia , Humanos , Tromboembolia/prevenção & controle
17.
Ann Biomed Eng ; 38(3): 841-53, 2010 Mar.
Artigo em Inglês | MEDLINE | ID: mdl-19960368

RESUMO

Thromboembolic complications of bileaflet mechanical heart valves (BMHV) are believed to be due to detrimental stresses imposed on blood elements by the hinge flows. Characterization of these flows is thus crucial to identify the underlying causes for complications. In this study, we conduct three-dimensional pulsatile flow simulations through the hinge of a BMHV under aortic conditions. Hinge and leaflet geometries are reconstructed from the Micro-Computed Tomography scans of a BMHV. Simulations are conducted using a Cartesian sharp-interface immersed-boundary methodology combined with a second-order accurate fractional-step method. Physiologic flow boundary conditions and leaflet motion are extracted from the Fluid-Structure Interaction simulations of the bulk of the flow through a BMHV. Calculations reveal the presence, throughout the cardiac cycle, of flow patterns known to be detrimental to blood elements. Flow fields are characterized by: (1) complex systolic flows, with rotating structures and slow reverse flow pattern, and (2) two strong diastolic leakage jets accompanied by fast reverse flow at the hinge bottom. Elevated shear stresses, up to 1920 dyn/cm2 during systole and 6115 dyn/cm2 during diastole, are reported. This study underscores the need to conduct three-dimensional simulations throughout the cardiac cycle to fully characterize the complexity and thromboembolic potential of the hinge flows.


Assuntos
Valva Aórtica/fisiologia , Valva Aórtica/cirurgia , Próteses Valvulares Cardíacas , Modelos Cardiovasculares , Velocidade do Fluxo Sanguíneo , Simulação por Computador , Análise de Falha de Equipamento , Humanos
18.
Clin Exp Pharmacol Physiol ; 36(2): 225-37, 2009 Feb.
Artigo em Inglês | MEDLINE | ID: mdl-19220329

RESUMO

1. Artificial heart valves have been in use for over five decades to replace diseased heart valves. Since the first heart valve replacement performed with a caged-ball valve, more than 50 valve designs have been developed, differing principally in valve geometry, number of leaflets and material. To date, all artificial heart valves are plagued with complications associated with haemolysis, coagulation for mechanical heart valves and leaflet tearing for tissue-based valve prosthesis. For mechanical heart valves, these complications are believed to be associated with non-physiological blood flow patterns. 2. In the present review, we provide a bird's-eye view of fluid mechanics for the major artificial heart valve types and highlight how the engineering approach has shaped this rapidly diversifying area of research. 3. Mechanical heart valve designs have evolved significantly, with the most recent designs providing relatively superior haemodynamics with very low aerodynamic resistance. However, high shearing of blood cells and platelets still pose significant design challenges and patients must undergo life-long anticoagulation therapy. Bioprosthetic or tissue valves do not require anticoagulants due to their distinct similarity to the native valve geometry and haemodynamics, but many of these valves fail structurally within the first 10-15 years of implantation. 4. These shortcomings have directed present and future research in three main directions in attempts to design superior artificial valves: (i) engineering living tissue heart valves; (ii) development of advanced computational tools; and (iii) blood experiments to establish the link between flow and blood damage.


Assuntos
Bioprótese , Circulação Coronária/fisiologia , Próteses Valvulares Cardíacas , Valvas Cardíacas/fisiologia , Modelos Cardiovasculares , Animais , Fenômenos Biomecânicos/fisiologia , Humanos , Desenho de Prótese
19.
Clin Neurol Neurosurg ; 111(1): 10-7, 2009 Jan.
Artigo em Inglês | MEDLINE | ID: mdl-18930587

RESUMO

OBJECT: Intramedullary spinal cord metastasis (ISCM) is a rare but devastating complication of cancer. Due to both widespread MRI availability and longer survival of cancer patients, the probability of discovering an ISCM during the course of the disease has increased and raised issues regarding the management of these patients, and particularly the place of surgery. In this study, we assess predictive factors for surgical outcome and survival. PATIENTS AND METHODS: We retrospectively reviewed a series of 19 patients consecutively admitted in our institution from 1993 to 2006 for ISCM, representing the second largest series published in the literature. MRI was performed on all patients. Thirteen underwent microsurgical excision of ISCM. Functional outcome was evaluated and factors influencing survival were statistically analyzed. RESULTS: Median survival was statistically longer when surgery was performed (7.4 vs. 2.6 months). Preoperative neurological status, nature of primary cancer, presence of systemic and/or CNS metastases influenced survival, but differences were without statistical significance. Neurological status improved in 58% (11/19) of operated patients. CONCLUSIONS: Optimal management of patients with ISCM is difficult due to the wide variety of clinical situations and the lack of controlled studies on the results of different therapeutic options. Diagnosis should be made as early as possible and surgical resection should be considered as the primary treatment whenever feasible, particularly in the case of rapidly progressive neurological deficits and when a clear cleavage plane exists. Our study shows that surgery could result in both increased survival rate and significant improvement of neurological function.


Assuntos
Neoplasias da Medula Espinal/secundário , Neoplasias da Medula Espinal/cirurgia , Adulto , Idoso , Neoplasias da Mama/patologia , Carcinoma de Células Pequenas/secundário , Carcinoma de Células Pequenas/cirurgia , Diagnóstico Precoce , Feminino , Humanos , Estimativa de Kaplan-Meier , Neoplasias Pulmonares/patologia , Imageamento por Ressonância Magnética/métodos , Imageamento por Ressonância Magnética/estatística & dados numéricos , Masculino , Microcirurgia/métodos , Microcirurgia/estatística & dados numéricos , Pessoa de Meia-Idade , Prognóstico , Estudos Retrospectivos , Fatores de Risco , Neoplasias da Medula Espinal/diagnóstico , Fatores de Tempo , Resultado do Tratamento
20.
Exp Fluids ; 45(6): 987-997, 2008 Dec.
Artigo em Inglês | MEDLINE | ID: mdl-22997481

RESUMO

Complex applications in fluid dynamics research often require more highly resolved velocity data than direct measurements or simulations provide. The advent of stereo PIV and PCMR techniques has advanced the state-of-the-art in flow velocity measurement, but 3D spatial resolution remains limited. Here a new technique is proposed for velocity data interpolation to address this problem. The new method performs with higher quality than competing solutions from the literature in terms of accurately interpolating velocities, maintaining fluid structure and domain boundaries, and preserving coherent structures.

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