Personne :
Dagenais, François.

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Département chirurgie, Faculté de médecine, Université Laval
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Voici les éléments 1 - 10 sur 12
  • Publication
    RNA expression profile of calcified bicuspid, tricuspid, and normal human aortic valves by RNA sequencing
    (American Physiological Society, 2016-10-01) Gaudreault, Nathalie; Tremblay-Marchand, Joël; Kalavrouziotis, Dimitri; Droit, Arnaud; Guauque-Olarte, Sandra; Bossé, Yohan; Seidman, Jonathan G.; Pibarot, Philippe; Body, Simon C.; Dagenais, François.; Mathieu, Patrick
    The molecular mechanisms leading to premature development of aortic valve stenosis (AS) in individuals with a bicuspid aortic valve are unknown. The objective of this study was to identify genes differentially expressed between calcified bicuspid aortic valves (BAVc) and tricuspid valves with (TAVc) and without (TAVn) AS using RNA sequencing (RNA-Seq). We collected 10 human BAVc and nine TAVc from men who underwent primary aortic valve replacement. Eight TAVn were obtained from men who underwent heart transplantation. mRNA levels were measured by RNA-Seq and compared between valve groups. Two genes were upregulated, and none were downregulated in BAVc compared with TAVc, suggesting a similar gene expression response to AS in individuals with bicuspid and tricuspid valves. There were 462 genes upregulated and 282 downregulated in BAVc compared with TAVn. In TAVc compared with TAVn, 329 genes were up- and 170 were downregulated. A total of 273 upregulated and 147 downregulated genes were concordantly altered between BAVc vs. TAVn and TAVc vs. TAVn, which represent 56 and 84% of significant genes in the first and second comparisons, respectively. This indicates that extra genes and pathways were altered in BAVc. Shared pathways between calcified (BAVc and TAVc) and normal (TAVn) aortic valves were also more extensively altered in BAVc. The top pathway enriched for genes differentially expressed in calcified compared with normal valves was fibrosis, which support the remodeling process as a therapeutic target. These findings are relevant to understand the molecular basis of AS in patients with bicuspid and tricuspid valves.
  • Publication
    Accès libre
    Sex-related discordance between aortic valve calcification and hemodynamic severity of aortic stenosis : is valvular fibrosis the explanation?
    (Grune & Stratton, 2016-11-22) Trahan, Sylvain; Couture, Christian; Mohammadi, Siamak; Côté, Nancy; Joubert, Philippe; Bossé, Yohan; Clavel, Marie-Annick; Pagé, Sylvain; Dagenais, François.; Mathieu, Patrick; Simard, Louis
    Rationale: Calcific aortic stenosis (AS) is characterized by calcium deposition in valve leaflets. However, women present lower aortic valve calcification (AVC) loads than men for the same AS hemodynamic severity. Objective: We thus aimed to assess sex-differences in aortic valve fibro-calcific remodelling. Methods and Results: One hundred and twenty-five patients underwent Doppler-echocardiography and multidetector-computed-tomography within 3 months prior to aortic valve replacement. Explanted stenotic tricuspid aortic valves were weighed and fibrosis degree was determined. Sixty-four men and 39 women were frequency-matched for age, body mass index (BMI), hypertension, renal disease, diabetes, and AS severity. Mean age was 75±9years, mean gradient (41±18mmHg) and indexed aortic valve area (0.41±0.12cm2/m2) were similar between men and women (all p=0.18). Median AVC (1973[1124-3490]AU) and mean valve weight (2.36±0.99g) were lower in women compared to men (both p<0.0001). AVC density correlated better with valve weight in men (r2=0.57; p<0.0001) than in women (r2=0.26; p=0.0008). After adjustment for age, BMI, AVC density and aortic annulus diameter, female sex was an independent risk factor for higher fibrosis score in AS valves (p=0.003). Picrosirius red staining of explanted valves showed greater amount of collagen fibers (p=0.01) and Masson's trichrome staining revealed a greater proportion of dense connective tissue (p=0.02) in women compared to men. Conclusions: In this series with tricuspid aortic valve and similar AS severity, women have less valvular calcification but more fibrosis compared to men. These findings suggest that the pathophysiology of the disease and thus potential targets for drug development may be different according to sex.
  • Publication
    Accès libre
    Impact of aortic stenosis severity and its interaction with prosthesis-patient mismatch on operative mortality following aortic valve replacement.
    (ICR, 2012-03-02) Girerd, Nicolas; Charbonneau, Éric; Dumont, Éric; Magne, Julien; Baillot, Richard; Voisine, Pierre; Pibarot, Philippe; Dumesnil, Jean G.; Dagenais, François.; Mathieu, Patrick
    The optimal timing of aortic valve replacement (AVR) in patients with severe aortic stenosis (AS) is a source of debate. Moreover, it has been shown previously that prosthesis-patient mismatch (PPM) is an independent predictor of operative mortality after AVR. The study aim was to assess the effect of the preoperative severity of AS and its interaction with PPM with respect to operative mortality after AVR.
  • Publication
    The impact of complete revascularization on long-term survival is strongly dependent on age
    (Little, Brown & Co., 2012-11-01) Charbonneau, Éric; Dumont, Éric; Magne, Julien; Baillot, Richard; Voisine, Pierre; Mohammadi, Siamak; Doyle, Daniel; Girerd, Nicolas; Pibarot, Philippe; Dagenais, François.; Rabilloud, Muriel; Mathieu, Patrick
    BACKGROUND: Complete revascularization during coronary artery bypass grafting (CABG) has been reported to be associated with better short-term and long-term outcomes. We hypothesized that the survival benefit of complete revascularization would be less in old patients than in young patients. METHODS: We analyzed data from 6,539 consecutive patients who had undergone a first isolated on-pump CABG procedure between 2000 and 2008. We investigated the impact of complete revascularization and its interaction with age on operative and long-term survival using propensity-score-based analyses. RESULTS: Patients with incomplete (versus complete) revascularization (n=318 [4.9%]) were sicker overall. During a mean follow-up of 5.8±2.2 years, 909 patients died. In the propensity-score-matched analysis, operative mortality was not significantly different between patients with complete revascularization and those with incomplete revascularization (1.9% versus 2.8%; odds ratio [OR], 1.46; 95% confidence interval [CI], 0.56-3.46; p=0.48). In contrast, incomplete revascularization had an independent negative impact on long-term survival, which was strongly age dependent (hazard ratio [HR] for interaction, 0.96 per year increment; p=0.02). In a propensity-score-matched analysis, incomplete revascularization was independently associated with higher long-term mortality in patients younger than 60 years (HR, 3.27; 95% CI, 1.21-8.86; p=0.02), whereas it was not in patients 60 to 70 years and 70 years of age and older (p=0.87 and p=0.24, respectively). CONCLUSIONS: Contrary to what is observed in patients younger than 60 years, complete revascularization does not seem to improve long-term survival in older patients. This suggests that elderly patients at high operative risk may be considered, when deemed clinically appropriate, for limited coronary revascularization
  • Publication
    Accès libre
    Postoperative atrial fibrillation predicts long-term survival after aortic-valve surgery but not after mitral-valve surgery : a retrospective study.
    (BMJ Publishing, 2011-10-27) Magne, Julien; Voisine, Pierre; Girerd, Nicolas; Pibarot, Philippe; Dagenais, François.; Mathieu, Patrick
    Background: Postoperative atrial fibrillation (POAF) has been reported to be associated with reduced long-term survival after isolated coronary artery bypass grafting surgery. The objective of this study was to determine the impact of POAF on long-term survival after valvular surgery. Methods: The authors retrospectively analysed the preoperative and operative data of 2986 consecutive patients with no preoperative history of atrial fibrillation undergoing first valvular surgery (aortic-valve replacement (AVR), mitral valve replacement or mitral valve repair (MVR/MVRp) with or without coronary artery bypass grafting surgery) in their institution between 1995 and 2008 (median follow-up 5.31 years, range 0.1-15.0). The authors investigated the impact of POAF on survival using multivariable Cox regression. Results: Patients with POAF were older, and were more likely to have hypertension or renal failure when compared with patients without POAF. The 12-year survival in patients with POAF was 45.7±2.8% versus 61.4±2.1% in patients without POAF (p<0.001). On a multivariable analysis, when adjusting for age and other potential confounding factors, POAF tended to be associated with lower long-term survival (HR for all-cause death (HR)=1.17, 95% CI 1.00 to 1.38, p=0.051). The authors also analysed this association separately in patients with AVR and those with MVR/MVRp. In the multivariable analysis, POAF was a significant predictor of higher long-term mortality in patients with AVR (HR=1.22, CI 1.02 to 1.45, p=0.03) but not in patients with MVR/MVRp (HR=0.87, CI 0.58 to 1.29, p=0.48). Conclusions: POAF is significantly associated with long-term mortality following AVR but not after MVR/MVRp. The underlying factors involved in the pathogenesis of POAF after MVR/MVRp may partially account for the lack of association between POAF and survival in these patients.
  • Publication
    Accès libre
    Genetic association analyses highlight IL6, ALPL, and NAV1 as three new susceptibility genes underlying calcific aortic valve stenosis
    (American Heart Association, 2019-10-15) Gaudreault, Nathalie; Dina, Christian; Thériault, Sébastien; Messika-Zeitoun, David; Arsenault, Benoit; Le Scouarnec, Solena; Capoulade, Romain; Boureau, Anne-Sophie; Bossé, Yohan; Rigade, Sidwell; Lamontagne, Maxime; Li, Zhonglin; Pibarot, Philippe; Simonet, Floriane; Clavel, Marie-Annick; Dagenais, François.; Mathieu, Patrick; Lecointe, Simon; Baron, Estelle; Bonnaud, Stéphanie; Karakachoff, Matilde; Charpentier, Eric; Fellah, Imen; Roussel, Jean-Christian; Verhoye, Jean Philippe; Baufreton, Christophe; Probst, Vincent; Roussel, Ronan; Redon, Richard; Le Tourneau, Thierry; Schott, Jean-Jacques
    Background: Calcific aortic valve stenosis (CAVS) is a frequent and life-threatening cardiovascular disease for which there is currently no medical treatment available. To date, only 2 genes, LPA and PALMD, have been identified as causal for CAVS. We aimed to identify additional susceptibility genes for CAVS. Methods: A GWAS (genome-wide association study) meta-analysis of 4 cohorts, totaling 5115 cases and 354 072 controls of European descent, was performed. A TWAS (transcriptome-wide association study) was completed to integrate transcriptomic data from 233 human aortic valves. A series of post-GWAS analyses were performed, including fine-mapping, colocalization, phenome-wide association studies, pathway, and tissue enrichment as well as genetic correlation with cardiovascular traits. Results: In the GWAS meta-analysis, 4 loci achieved genome-wide significance, including 2 new loci: IL6 (interleukin 6) on 7p15.3 and ALPL (alkaline phosphatase) on 1p36.12. A TWAS integrating gene expression from 233 human aortic valves identified NAV1 (neuron navigator 1) on 1q32.1 as a new candidate causal gene. The CAVS risk alleles were associated with higher mRNA expression of NAV1 in valve tissues. Fine-mapping identified rs1800795 as the most likely causal variant in the IL6 locus. The signal identified colocalizes with the expression of the IL6 RNA antisense in various tissues. Phenome-wide association analyses in the UK Biobank showed colocalized associations between the risk allele at the IL6 lead variant and higher eosinophil count, pulse pressure, systolic blood pressure, and carotid artery procedures, implicating modulation of the IL6 pathways. The risk allele at the NAV1 lead variant colocalized with higher pulse pressure and higher prevalence of carotid artery stenosis. Association results at the genome-wide scale indicated genetic correlation between CAVS, coronary artery disease, and cardiovascular risk factors. Conclusions: Our study implicates 3 new genetic loci in CAVS pathogenesis, which constitute novel targets for the development of therapeutic agents.
  • Publication
    Accès libre
    Transvalvular flow, sex, and survival after valve replacement surgery in patients with severe aortic stenosis
    (Elsevier, 2020-04-28) Bilodeau, Anthony; Guzzetti, Ezequiel; Kalavrouziotis, Dimitri; Zhang, Bin; Couture, Christian; Annabi, Mohamed Salah; Pibarot, Philippe; Clavel, Marie-Annick; Dagenais, François.
    Background : The respective impacts of transvalvular flow, gradient, sex, and their interactions on mortality in patients with severe aortic stenosis undergoing surgical aortic valve replacement (AVR) are unknown. Objectives : This study sought to compare the impact of pre-operative flow-gradient patterns on mortality after AVR and to examine whether there are sex differences. Methods : This study analyzed clinical, echocardiographic, and outcome data prospectively collected in 1,490 patients (544 women [37%]), with severe aortic stenosis and preserved left ventricular ejection fraction who underwent AVR. Results : In this cohort, 601 patients (40%) had normal flow (NF) with high gradient (HG), 405 (27%) NF with low gradient (LG), 246 (17%) paradoxical low flow (LF)/HG, and 238 (16%) LF/LG. During a median follow-up of 2.42 years (interquartile range: 1.04 to 4.29 years), 167 patients died. Patients with LF/HG exhibited the highest mortality after AVR (hazard ratio [HR]: 2.01; 95% confidence interval [CI]: 1.33 to 3.03; p < 0.01), which remained significant after multivariate adjustment (HR: 1.96; 95% CI: 1.29 to 2.98; p < 0.01). Both LF/LG and NF/LG patients had comparable outcome to NF/HG (p ≥ 0.47). Optimal thresholds of stroke volume index were obtained for men (40 ml/m2) and women (32 ml/m2). Using these sex-specific cutpoints, paradoxical LF was independently associated with increased mortality in both women (adjusted HR: 2.05; 95% CI: 1.21 to 3.47; p < 0.01) and men (adjusted HR: 1.54; 95% CI: 1.02 to 2.32; p = 0.042), whereas guidelines’ threshold (35 ml/m2) does not. Conclusions : Paradoxical LF/HG was associated with higher mortality following AVR, suggesting that a reduced flow is a marker of disease severity even in patients with HG aortic stenosis. Early surgical AVR (i.e., before gradient attains 40 mm Hg) might be preferable in these patients. Furthermore, the use of sex-specific thresholds (<40 ml/m2 for men and <32 ml/m2 for women) to define low-flow outperforms the guidelines’ threshold of 35 ml/m2 in risk stratification after AVR.
  • Publication
    Accès libre
    A transcriptome-wide association study identifies PALMD as a susceptibility gene for calcific aortic valve stenosis
    (Nature Publishing Group, 2018-03-07) Gaudreault, Nathalie; Thériault, Sébastien; Rosa, Mickael; Boulanger, Marie-Chloé; Capoulade, Romain; Messika-Zeitoun, David; Bossé, Yohan; Lamontagne, Maxime; Pibarot, Philippe; Clavel, Marie-Annick; Dagenais, François.; Mathieu, Patrick
    Calcific aortic valve stenosis (CAVS) is a common and life-threatening heart disease and the current treatment options cannot stop or delay its progression. A GWAS on 1009 cases and 1017 ethnically matched controls was combined with a large-scale eQTL mapping study of human aortic valve tissues (n = 233) to identify susceptibility genes for CAVS. Replication was performed in the UK Biobank, including 1391 cases and 352,195 controls. A tran- scriptome-wide association study (TWAS) reveals PALMD (palmdelphin) as significantly associated with CAVS. The CAVS risk alleles and increasing disease severity are both associated with decreased mRNA expression levels of PALMD in valve tissues. The top variant identified shows a similar effect and strong association with CAVS (P = 1.53 × 10−10) in UK Biobank. The identification of PALMD as a susceptibility gene for CAVS provides insights into the genetic nature of this disease, opens avenues to investigate its etiology and to develop much-needed therapeutic options.
  • Publication
    Accès libre
    Impact of metabolic syndrome and/or diabetes mellitus on left ventricular mass and remodeling in patients with aortic stenosis before and after aortic valve replacement
    (ScienceDirect, 2019-01-01) Guzzetti, Ezequiel; Shen, Mylène; Voisine, Pierre; Annabi, Mohamed Salah; Poirier, Paul; Piché, Marie-Eve; Zenses, Anne-Sophie; Pibarot, Philippe; Clavel, Marie-Annick; Ong, Géraldine; Dagenais, François.; Tastet, Lionel; Salaun, Erwan
    Background: In aortic stenosis (AS), metabolic syndrome (MetS) and diabetes mellitus (DM) are associated with more pronounced left ventricular hypertrophy (LVH) and more concentric remodeling. We aimed to assess the impact of MetS and DM on left ventricular (LV) mass, remodeling and LV mass regression after aortic valve replacement (AVR) in patients with severe AS. Method: We included 177 patients with severe AS and preserved LVEF (>50%). All patients had comprehensive echocardiography before and one year after AVR. Results: Twenty-seven percent (27%) of patients had MetS, 21% DM and 52% neither MetS nor DM (No MetS-DM). Prior to AVR, indexed LV mass (LVMi) was higher in MetS and DM groups compared to NoMetS-DM group (56.1±14.2, 56.2±18.2 vs. 49.2±14.1 g/m2.7 respectively; p<0.01). Prevalence of LV hypertrophy was higher in MetS and DM than in NoMetS-DM patients (66%, 65% vs 44%, p<0.01) as well as LV mass to-end-diastolic volume ratio (2.10±0.44 and 2.21±0.63 vs 1.96±0.41 g/ml respectively, p=0.03). One year after AVR, decrease in LVMi was significant (p<0.001) in all 3 groups. DM and MetS were independently associated with higher baseline LVMi (p<0.05). MetS was independently associated with less LVM regression and higher LVMi 1 year after AVR. MetS and DM groups showed more residual LV hypertrophy than NoMetS-DM patients (57%, 38% and 17%, p<0.01). Conclusions: MetS and DM were independently associated with a higher preoperative LVMi and more concentric remodeling. One year after AVR, MetS was associated with less LVMi regression and higher LVMi. MetS and DM patients remained with more residual LV hypertrophy
  • Publication
    Pre- and post-operative stroke volume impact after surgical aortic valve replacement for severe aortic stenosis
    (Elsevier Biomedical, 2020-10-19) Guzzetti, Ezequiel; Poulin, Anthony; Kalavrouziotis, Dimitri; Annabi, Mohamed Salah; Pibarot, Philippe; Clavel, Marie-Annick; Dagenais, François.