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Blais, Claudia

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Blais

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Claudia

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Université Laval. Faculté de pharmacie

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ncf10587011

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Voici les éléments 1 - 10 sur 10
  • PublicationAccès libre
    Nouvelles avenues en regard du diagnostic et du traitement de la sténose valvulaire aortique avec bas débit cardiaque
    (2006) Blais, Claudia; Pibarot, Philippe; Dumesnil, Jean G.
    Parmi les patients avec sténose aortique (SA), 5% d'entre-eux ont une fonction ventriculaire gauche sévèrement réduite. Malgré ce faible pourcentage, ces patients représentent le sous-groupe qui suscite le plus de défis et de controverses. En plus d'avoir un mauvais pronostic à court terme, la présence d'un faible débit cardiaque et d'une faible fraction d'éjection peut fausser l'évaluation de la sévérité de la sténose et par conséquent conduire à une mauvaise décision thérapeutique. Afin de décider de l'éventuelle nécessité de remplacer la valve aortique, il est donc essentiel de pouvoir distinguer les patients ayant une sténose vraiment sévère de ceux ayant une sténose pseudo-sévère, c'est-à-dire un ventricule gauche défaillant qui est incapable d'ouvrir complètement une valve légèrement ou modérément sténosée. La distinction est cruciale car le remplacement valvulaire sera bénéfique seulement dans le cas des sténoses vraiment sévères. Parmi les nombreux indices utilisés pour évaluer le degré de sévérité de la SA, des doutes subsistaient sur la dépendance face au débit de la résistance valvulaire. Nous avons démontré de façon théorique puis pratique, sur modèle in vitro et chez des patients, que la résistance valvulaire est dépendante du débit transvalvulaire. Cet indice n'a donc pas d'avantage par rapport aux autres indices pour évaluer le degré d'obstruction valvulaire des patients avec SA à bas débit. Étant donné que tous les indices de sévérité ont la grande limitation d'être dépendants du débit transvalvulaire, nous avons proposé un nouvel indice, l'aire valvulaire projetée à débit normal. Cet indice permet une standardisation de l'évaluation de la sévérité de la sténose chez des patients ayant différents débits et améliore la précision pour différencier les patients ayant une sténose vraiment sévère de ceux ayant une sténose pseudo-sévère. Ces patients avec SA à bas débit présentent un risque opératoire élevé, variant de 5 à 33%. Le troisième article démontre que la disproportion patient-prothèse (DPP) est un facteur de risque important pour la mortalité opératoire, et particulièrement pour les patients avec SA et dysfonction ventriculaire gauche concomitante. La DPP est aussi le seul facteur de risque qui puisse être évité au moyen d'une stratégie de prévention lors de l'opération.
  • PublicationAccès libre
    Temporal trends of aortic stenosis and comorbid chronic kidney disease in the province of Quebec, Canada
    (London BMJ Publishing Group Ltd, 2022-06-01) Hamel, Denis; Jean, Sonia; Mac-Way, Fabrice; Blais, Claudia; Pibarot, Philippe; Khelifi, Nada; Clavel, Marie-Annick
    Objective: To investigate temporal trends of chronic kidney disease (CKD) among patients with incident aortic stenosis (AS) and to compare these trends with that of a matched control population. Methods: Using the Quebec Integrated Chronic Disease Surveillance System, we performed a population-based nested case-control study including 108 780 patients newly hospitalised with AS and 543 900 age-matched, sex-matched and fiscal year-matched patients without AS from 2000 to 2016 in Quebec (Canada). Three subgroups were considered. Dialysis subgroup had at least two outpatient billing codes of dialysis. The predialysis subgroup had at least one hospital or two billing diagnostic codes of CKD. The remaining individuals were included in the non-CKD subgroup. We estimated overall and sex-specific standardised annual proportions of CKD subgroups through direct standardisation using the 2016-2017 age structure of the incident AS cohort. The trends overtime were estimated through fitting robust Poisson regression models. Age-specific distribution of AS and control population were assessed for each subgroup. Results: From 2000 to 2016, age-standardised proportions of patients with AS with dialysis and predialysis increased by 41% (99% CI 12.0% to 78.1%) and by 45% (99% CI 39.1% to 51.6%), respectively. Inversely, age-standardised proportions of dialysis and pre-dialysis among non-AS patients decreased by 63% (99% CI 55.8% to 68.7%) and by 32% (99% CI 29.9% to 34.6%), respectively, during the same study period. In patients with and without AS, age-standardised annual proportions of males in predialysis were significantly higher than females in most of the study period. Patients with AS on dialysis and predialysis were younger than their respective controls (dialysis: 29.6% vs 45.1% had ≥80 years, predialysis: 60.8% vs 72.7% had ≥80 years). Conclusions: Over time, the proportion of patients with CKD increased significantly and remained consistently higher in incident AS individuals compared with controls. Our results highlight the need to investigate whether interventions targeting CKD risk factors may influence AS incidence in the future.
  • PublicationRestreint
    Le modèle québécois de surveillance des maladies chroniques basé sur l’utilisation des données médico-administratives jumelées
    (Santé publique France, 2013-12-19) Saint-Laurent, Danielle; Rochette, Louis; Blais, Claudia; Sirois, Caroline; Émond, Valérie
    L'évolution rapide du contexte démographique, politique et environnemental ainsi que les changements continus de la pratique et des connaissances médicales influencent grandement le développement et l'issue des maladies et, par conséquent, la façon d'en assurer la surveillance épidémiologique. Pour répondre aux impératifs contextuels, le Système intégré de surveillance des maladies chroniques du Québec (Sismacq) s'est développé sur la base du jumelage de cinq fichiers médico-administratifs couvrant le fichier des personnes assurées et l'offre de services de santé des Québécois, depuis la consultation médicale jusqu'à l'hospitalisation, en passant par la consommation des médicaments et se terminant par le décès. Le but de cet article est de décrire le Sismacq. Le potentiel des sources de données jumelées permet non seulement d'établir les prévalences et les incidences des maladies, mais aussi d'étudier des cohortes de personnes atteintes de maladies et d'analyser les issues de santé comme le fardeau des maladies et l'utilisation des ressources. Cette approche intégrée offre également une opportunité de comprendre le cumul des maladies et les comorbidités. Le Sismacq est basé sur trois étapes méthodologiques distinctes que sont 1) l'extraction et le jumelage des données, 2) les analyses et la production des indicateurs et 3) la diffusion. (R.A.)
  • PublicationRestreint
    Evolution of the burden of aortic stenosis by sex in the province of Quebec between 2006 and 2018
    (BMJ Publishing Group, 2022-03-21) Frieden, Philipp; Blais, Claudia; Hamel, Denis; Gamache, Philippe; Pibarot, Philippe; Clavel, Marie-Annick
    Objectives: To evaluate the evolution of the burden of aortic stenosis (AS) by sex in the province of Quebec from 2006-2007 to 2018-2019 and compare the percentage of mortality between people who underwent aortic valve intervention and those who did not. Methods: Persons aged ≥20 years were identified from the Quebec Integrated Chronic Disease Surveillance System using International Classification of Diseases and intervention codes in the hospital files. Results: In 2018, the crude prevalence and incidence of AS were 0.89% (99% CI 0.89 to 0.90) (n=59 025) and 1.39 per 1000 (1.35 to 1.43) (n=9105), respectively. Age-standardised prevalence and incidence of AS diagnosis increased between 2006 and 2018 from 0.67% (0.66 to 0.68) to 0.75% (0.74 to 0.76) and from 0.91 per 1000 (0.88 to 0.95) to 1.20 per 1000 (1.17 to 1.23), respectively. Among incident AS, the age-standardised percentage of valve interventions increased from 11.7% (10.9 to 12.6) to 14.5% (13.9 to 15.3). This increase was only observed in men. The 30-day mortality was stable among patients with incident AS treated conservatively, from 6.9% (6.5 to 7.4) to 7.3% (6.9 to 7.6), and decreased from 7.6% (6.1 to 9.3) to 3.8% (3.1 to 4.7) among operated patients with incident AS. This decrease was only observed in women. However, from 2010, the age-adjusted mortality among prevalent AS tended to be higher in women. Conclusions: In the province of Quebec, age-standardised prevalence and incidence of AS diagnosis increased between 2006 and 2018. Among incident AS, there was an increase in valve intervention in men and a decrease in 30-day mortality in women who underwent valve intervention. Overall and age-standardised mortality remained higher in women.
  • PublicationRestreint
    Le système intégré de surveillance des maladies chroniques du Québec (SISMACQ) : une approche novatrice
    (Agence de santé publique du Canada, 2014-11-01) Doucet, Mariève; Ruel, Guillaume; Plante, Céline; Hamel, Denis; Rochette, Louis; Jean, Sonia; Blais, Claudia; Simard, Marc; Sirois, Caroline
    Introduction : Avec l’accroissement du fardeau des maladies chroniques, la surveillance est fondamentale pour améliorer la prévention et la prise en charge de ces dernières. L’Institut national de santé publique du Québec a donc développé un système novateur de surveillance des maladies chroniques, le Système intégré de surveillance des maladies chroniques du Québec (SISMACQ), dont les principales caractéristiques, les forces et les limites sont présentées ici. Méthodologie : Le SISMACQ est le résultat du jumelage de cinq fichiers médico-administratifs. Mises à jour annuellement, ses données couvrent actuellement la période du 1er janvier 1996 au 31 mars 2012. Trois étapes en caractérisent le modèle opérationnel : 1) l’extraction et le jumelage des données médico-administratives grâce à divers critères de sélection; 2) les analyses (principalement la validation des définitions) et la production des mesures de surveillance et 3) l’interprétation, le dépôt et la diffusion de l’information. Le SISMACQ permet actuellement l’étude des maladies chroniques suivantes : diabète, maladies cardiovasculaires, maladies respiratoires, ostéoporose, maladies ostéoarticulaires, troubles mentaux et Alzheimer et maladies apparentées. Il permet également l’analyse de la multimorbidité et de la polypharmacie. Résultats : Pour 2011-2012, le SISMACQ contenait des données sur 7 995 963 Québécois, et leur moyenne d’âge était de 40,8 ans. Parmi eux, 95,3 % répondaient à au moins un critère de sélection permettant l’application de définitions de cas pour la surveillance des maladies chroniques. Cette proportion variait avec l’âge : de 90,1 % chez les Québécois de 19 ans et moins à 99,3 % chez ceux de 65 ans et plus. Conclusion : Le SISMACQ permet la production de données, à l’échelle de la population, sur le fardeau de plusieurs maladies chroniques, sur l’utilisation des services de santé et sur la consommation de médicaments. Il rend possible l’étude intégrée de la combinaison de plusieurs maladies, une approche jusqu’à présent rarement mise en œuvre dans un contexte de surveillance populationnelle. Le SISMACQ répond aux attributs essentiels d’un système de surveillance et aide à la diffusion de l’information auprès des décideurs en vue d’actions en santé publique.
  • PublicationRestreint
    B-type natriuretic peptide in low-flow, low-gradient aortic stenosis : relationship to hemodynamics and clinical outcome : results from the Multicenter Truly or Pseudo-Severe Aortic Stenosis (TOPAS) study.
    (American Heart Association, 2007-06-05) Bergler-Klein, Jutta; Fuchs, Christina; Mundigler, Gerald; Mohty, Dania; Hachicha, Zeineb; Burwash, Ian G.; Blais, Claudia; Pibarot, Philippe; Dumesnil, Jean G.; Beanlands, Robert S. B.; Walter-Publig, Nicole; Rader, Florian; Baumgartner, Helmut
    BACKGROUND: The prognostic value of B-type natriuretic peptide (BNP) is unknown in low-flow, low-gradient aortic stenosis (AS). We sought to evaluate the relationship between AS and rest, stress hemodynamics, and clinical outcome. METHODS AND RESULTS: BNP was measured in 69 patients with low-flow AS (indexed effective orifice area < 0.6 cm2/m2, mean gradient < or = 40 mm Hg, left ventricular ejection fraction < or = 40%). All patients underwent dobutamine stress echocardiography and were classified as truly severe or pseudosevere AS by their projected effective orifice area at normal flow rate of 250 mL/s (effective orifice area < or = 1.0 cm2 or > 1.0 cm2). BNP was inversely related to ejection fraction at rest (Spearman correlation coefficient r(s)=-0.59, P<0.0001) and at peak stress (r(s)=-0.51, P<0.0001), effective orifice area at rest (r(s)=-0.50, P<0.0001) and at peak stress (r(s)=-0.46, P=0.0002), and mean transvalvular flow (r(s)=-0.31, P=0.01). BNP was directly related to valvular resistance (r(s)=0.42, P=0.0006) and wall motion score index (r(s)=0.36, P=0.004). BNP was higher in 29 patients with truly severe AS versus 40 with pseudosevere AS (median, 743 pg/mL [Q1, 471; Q3, 1356] versus 394 pg/mL [Q1, 191 to Q3, 906], P=0.012). BNP was a strong predictor of outcome. In the total cohort, cumulative 1-year survival of patients with BNP > or = 550 pg/mL was only 47+/-9% versus 97+/-3% with BNP < 550 (P<0.0001). In 29 patients who underwent valve replacement, postoperative 1-year survival was also markedly lower in patients with BNP > or = 550 pg/mL (53+/-13% versus 92+/-7%). CONCLUSIONS: BNP is significantly higher in truly severe than pseudosevere low-gradient AS and predicts survival of the whole cohort and in patients undergoing valve replacement.
  • PublicationRestreint
    Impact of valve prosthesis-patient mismatch on short-term mortality after aortic valve replacement
    (American Heart Association, 2003-08-26) Baillot, Richard; Doyle, Daniel; Blais, Claudia; Pibarot, Philippe; Dumesnil, Jean G.; Simard, Serge
    Background— The prosthesis used for aortic valve replacement (AVR) can be too small in relation to body size, thus causing valve prosthesis-patient mismatch (PPM) and abnormally high transvalvular pressure gradients. This study examined if there is a relation between PPM and short-term mortality after operation. Methods and Results— The indexed valve effective orifice area (EOA) was estimated for each type and size of prosthesis being implanted in 1266 consecutive patients and used to define PPM as not clinically significant if 0.85 cm2/m2, as moderate if 0.65 cm2/m2 and 0.85 cm2/m2, and as severe if 0.65 cm2/m2; it was correlated with 30-day mortality and compared with other relevant variables. Moderate or severe PPM was present in 38% of patients. Thirty-day mortality was 4.6% (58/1266 patients) and the strongest independent predictors in multivariate analysis were left ventricular ejection fraction 40% (P 0.007), infectious endocarditis (P 0.002), emergent/salvage operation (P 0.002), cardiopulmonary bypass time 120 minutes (P 0.001), and PPM (P 0.003). Relative risk of mortality was increased 2.1-fold (95% confidence interval, 1.2 to 3.7) in patients with moderate PPM and 11.4-fold (4.4 to 29.5) in those with severe PPM. Moreover, risk of mortality for every category of PPM was higher in patients with a left ventricular ejection fraction 40% as compared with 40% (nonsignificant PPM, 2.7 versus 1.0; moderate PPM, 7.1 versus 1.8; severe PPM, 77.1 versus 11.3). Conclusion— PPM is a strong and independent predictor of short-term mortality among patients undergoing AVR, and its impact is related both to its degree of severity and the status of left ventricular function. In contrast to other risk factors, moderate-severe PPM can be largely avoided with the use of a prospective strategy at the time of operation.
  • PublicationRestreint
    Projected valve area at normal flow rate improves the assessment of stenosis severity in patients with low-flow, low-gradient aortic stenosis : the multicenter TOPAS (truly or pseudo-severe aortic stenosis) study
    (American Heart Association, 2006-02-07) Kadem, Lyes; Burwash, Ian G.; Blais, Claudia; Mundigler, Gerald; Pibarot, Philippe; Dumesnil, Jean G.; Loho, Nicole; Rader, Florian; Baumgartner, Helmut; Beanlands, Robert S. B.; Chayer, Boris; Garcia, Damien; Durand, Louis-Gilles
    Background— We sought to investigate the use of a new parameter, the projected effective orifice area (EOAproj) at normal transvalvular flow rate (250 mL/s), to better differentiate between truly severe (TS) and pseudo-severe (PS) aortic stenosis (AS) during dobutamine stress echocardiography (DSE). Changes in various parameters of stenosis severity have been used to differentiate between TS and PS AS during DSE. However, the magnitude of these changes lacks standardization because they are dependent on the variable magnitude of the transvalvular flow change occurring during DSE. Methods and Results— The use of EOAproj to differentiate TS from PS AS was investigated in an in vitro model and in 23 patients with low-flow AS (indexed EOA <0.6 cm2/m2, left ventricular ejection fraction =40%) undergoing DSE and subsequent aortic valve replacement. For an individual valve, EOA was plotted against transvalvular flow (Q) at each dobutamine stage, and valve compliance (VC) was derived as the slope of the regression line fitted to the EOA versus Q plot; EOAproj was calculated as EOAproj=EOArest+VC×(250-Qrest), where EOArest and Qrest are the EOA and Q at rest. Classification between TS and PS was based on either response to flow increase (in vitro) or visual inspection at surgery (in vivo). EOAproj was the most accurate parameter in differentiating between TS and PS both in vitro and in vivo. In vivo, 15 of 23 patients (65%) had TS and 8 of 23 (35%) had PS. The percentage of correct classification was 83% for EOAproj and 91% for indexed EOAproj compared with percentages of 61% to 74% for the other echocardiographic parameters usually used for this purpose. Conclusions— EOAproj provides a standardized evaluation of AS severity with DSE and improves the diagnostic accuracy for distinguishing TS and PS AS in patients with low-flow, low-gradient AS.
  • PublicationRestreint
    Myocardial blood flow in patients with low-flow, low-gradient aortic stenosis : differences between true and pseudo-severe aortic stenosis. Results from the multicentre TOPAS (Truly or Pseudo-Severe Aortic Stenosis) study
    (BMJ, 2008-04-01) Burwash, Ian G.; Blais, Claudia; Lortie, Mireille; Pibarot, Philippe; Dumesnil, Jean G.; deKemp, Robert A.; Graf, Senta; Mundigler, Gerald; Khorsand, Aliasghar; Baumgartner, Helmut; Hachicha, Zeineb; DaSilva, Jean; Beanlands, Robert S. B.
    BACKGROUND: Impairment of myocardial flow reserve (MFR) in aortic stenosis (AS) with normal left ventricular function relates to the haemodynamic severity. OBJECTIVES: To investigate whether myocardial blood flow (MBF) and MFR differ in low-flow, low-gradient AS depending on whether there is underlying true-severe AS (TSAS) or pseudo-severe AS (PSAS). METHODS: In 36 patients with low-flow, low-gradient AS, dynamic [13N]ammonia PET perfusion imaging was performed at rest (n = 36) and during dipyridamole stress (n = 20) to quantify MBF and MFR. Dobutamine echocardiography was used to classify patients as TSAS (n = 18) or PSAS (n = 18) based on the indexed projected effective orifice area (EOA) at a normal flow rate of 250 ml/s (EOAI(proj )0.55 cm(2)/m(2)). RESULTS: Compared with healthy controls (n = 14), patients with low-flow, low-gradient AS had higher resting mean (SD) MBF (0.83 (0.21) vs 0.69 (0.09) ml/min/g, p = 0.001), reduced hyperaemic MBF (1.16 (0.31) vs 2.71 (0.50) ml/min/g, p<0.001) and impaired MFR (1.44 (0.44) vs 4.00 (0.91), p<0.001). Resting MBF and MFR correlated with indices of AS severity in low-flow, low-gradient AS with the strongest relationship observed for EOAI(proj) (r(s) = -0.50, p = 0.002 and r(s) = 0.61, p = 0.004, respectively). Compared with PSAS, TSAS had a trend to a higher resting MBF (0.90 (0.19) vs 0.77 (0.21) ml/min/g, p = 0.06), similar hyperaemic MBF (1.16 (0.31) vs 1.17 (0.32) ml/min/g, p = NS), but a significantly smaller MFR (1.19 (0.26) vs 1.76 (0.41), p = 0.003). An MFR <1.8 had an accuracy of 85% for distinguishing TSAS from PSAS. CONCLUSIONS: Low-flow, low-gradient AS is characterised by higher resting MBF and reduced MFR that relates to the AS severity. The degree of MFR impairment differs between TSAS and PSAS and may be of value for distinguishing these entities.
  • PublicationRestreint
    Comparison of valve resistance with effective orifice area regarding flow dependence
    (Elsevier, etc., 2001-07-01) Blais, Claudia; Pibarot, Philippe; Dumesnil, Jean G.; Garcia, Damien; Chen, Danmin; Durand, Louis-Gilles
    Aortic valve resistance has been proposed to represent the severity of aortic stenosis because some studies observed that it was less affected by change in flow than the valve-effective orifice area, but this issue remains controversial. The objective of this study was to systematically analyze the theoretical and practical determinants of these parameters in relation to changes in flow. Valve area and resistance in different valves were studied in vitro in a pulse duplicator system at different flow rates and in vivo in 90 subjects referred to either exercise or dobutamine infusion. Theoretical analysis and experimental results both demonstrated a unique relation between resistance (RES), valve-effective orifice area (EOA), and flow rate (Q): RES = K × (Q/EOA 2 ). Accordingly, in fixed stenoses or in mechanical valves, resistance increased markedly with flow rate both in vitro (+0.88 ± 0.26%/% of flow increase) and in vivo (mechanical valves: +2.09 ± 4.61, fixed stenotic valves: +0.59 ± 0.32%/%), whereas valve area did not change significantly (<0.2%/%). In contrast, in valves with a flexible orifice (bioprostheses and some patients with aortic stenosis), resistance was less increased due to the increase in valve area. Thus, both from a theoretical and a practical standpoint, valve resistance is much more flow dependent than valve area, particularly in fixed stenoses. Situations in which resistance does not increase with flow rate are unpredictable and are found in flexible valves when there is a concomitant increase in valve area.