Publications by authors named "Mikaël Trottier"

12 Publications

  • Page 1 of 1

F-Fluorodeoxyglucose Uptake Pattern in Noninfected Transcatheter Aortic Valves.

Circ Cardiovasc Imaging 2020 11 10;13(11):e011749. Epub 2020 Nov 10.

Department of Cardiology (D.d.V., A.A., G.M.-C., L.F., R.D., J.-M.P., M.C., J.R.-C.), Quebec Heart & Lung Institute, Laval University, Quebec City, Quebec, Canada.

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http://dx.doi.org/10.1161/CIRCIMAGING.120.011749DOI Listing
November 2020

Lipoprotein(a), Oxidized Phospholipids, and Aortic Valve Microcalcification Assessed by 18F-Sodium Fluoride Positron Emission Tomography and Computed Tomography.

CJC Open 2019 May 12;1(3):131-140. Epub 2019 Apr 12.

Centre de recherche de l'Institut universitaire de cardiologie et de pneumologie de Québec, Québec, Québec, Canada.

Background: Lipoprotein(a) (Lp[a]) is the preferential lipoprotein carrier of oxidized phospholipids (OxPLs) and a well-established genetic risk factor for calcific aortic valve stenosis (CAVS). Whether Lp(a) predicts aortic valve microcalcification in individuals without CAVS is unknown. Our objective was to estimate the prevalence of elevated Lp(a) and OxPL levels in patients with CAVS and to determine if individuals with elevated Lp(a) but without CAVS have higher aortic valve microcalcification.

Methods: We recruited 214 patients with CAVS from Montreal and 174 patients with CAVS and 108 controls from Québec City, Canada. In a second group of individuals with high (≥75 nmol/L, n = 27) or low (<75 nmol/L, n = 28) Lp(a) levels, 18F-sodium fluoride positron emission tomography/computed tomography was performed to determine the difference in mean tissue-to-background ratio (TBR) of the aortic valve.

Results: Patients with CAVS had 62.0% higher Lp(a) (median = 28.7, interquartile range [8.2-116.6] vs 10.9 [3.6-28.8] nmol/L, 0.0001), 50% higher OxPL-apolipoprotein-B (2.2 [1.3-6.0] vs 1.1 [0.7-2.6] nmol/L, 0.0001), and 69.9% higher OxPL-apolipoprotein(a) (7.3 [1.8-28.4] vs 2.2 [0.8-8.4] nmol/L, 0.0001) levels compared with individuals without CAVS (all 0.0001). Individuals without CAVS but elevated Lp(a) had 40% higher mean TBR compared with individuals with low Lp(a) levels (mean TBR = 1.25 ± 0.23 vs 1.15 ± 0.11,  = 0.02).

Conclusions: Elevated Lp(a) and OxPL levels are associated with prevalent CAVS in patients studied in an echocardiography laboratory setting. In individuals with elevated Lp(a), evidence of aortic valve microcalcification by 18F-sodium fluoride positron emission tomography/computed tomography is present before the development of clinically manifested CAVS.
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http://dx.doi.org/10.1016/j.cjco.2019.03.004DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC7063623PMC
May 2019

Genetic Variation in LPA, Calcific Aortic Valve Stenosis in Patients Undergoing Cardiac Surgery, and Familial Risk of Aortic Valve Microcalcification.

JAMA Cardiol 2019 07;4(7):620-627

Centre de Recherche de l'Institut Universitaire de Cardiologie et de Pneumologie de Québec, Québec City, Québec, Canada.

Importance: Genetic variants at the LPA locus are associated with both calcific aortic valve stenosis (CAVS) and coronary artery disease (CAD). Whether these variants are associated with CAVS in patients with CAD vs those without CAD is unknown.

Objective: To study the associations of LPA variants with CAVS in a cohort of patients undergoing heart surgery and LPA with CAVS in patients with CAD vs those without CAD and to determine whether first-degree relatives of patients with CAVS and high lipoprotein(a) (Lp[a]) levels showed evidence of aortic valve microcalcification.

Design, Setting, And Participants: This genetic association study included patients undergoing cardiac surgery from the Genome-Wide Association Study on Calcific Aortic Valve Stenosis in Quebec (QUEBEC-CAVS) study and patients with CAD, patients without CAD, and control participants from 6 genetic association studies: the UK Biobank, the European Prospective Investigation of Cancer (EPIC)-Norfolk, and Genetic Epidemiology Research on Aging (GERA) studies and 3 French cohorts. In addition, a family study included first-degree relatives of patients with CAVS. Data were collected from January 1993 to September 2018, and analysis was completed from September 2017 to September 2018.

Exposures: Case-control studies.

Main Outcomes And Measures: Presence of CAVS according to a weighted genetic risk score based on 3 common Lp(a)-raising variants and aortic valve microcalcification, defined as the mean tissue to background ratio of 1.25 or more, measured by fluorine 18-labeled sodium fluoride positron emission tomography/computed tomography.

Results: This study included 1009 individuals undergoing cardiac surgery and 1017 control participants in the QUEBEC-CAVS cohort; 3258 individuals with CAVS and CAD, 41 100 controls with CAD, 2069 individuals with CAVS without CAD, and 380 075 control participants without CAD in the UK Biobank, EPIC-Norfolk, and GERA studies and 3 French cohorts combined; and 33 first-degree relatives of 17 patients with CAVS and high Lp(a) levels (≥60 mg/dL) and 23 control participants with normal Lp(a) levels (<60 mg/dL). In the QUEBEC-CAVS study, each SD increase of the genetic risk score was associated with a higher risk of CAVS (odds ratio [OR], 1.35 [95% CI, 1.10-1.66]; P = .003). Each SD increase of the genetic risk score was associated with a higher risk of CAVS in patients with CAD (OR, 1.30 [95% CI, 1.20-1.42]; P < .001) and without CAD (OR, 1.33 [95% CI, 1.14-1.55]; P < .001). The percentage of individuals with a tissue to background ratio of 1.25 or more or CAVS was higher in first-degree relatives of patients with CAVS and high Lp(a) (16 of 33 [49%]) than control participants (3 of 23 [13%]; P = .006).

Conclusions And Relevance: In this study, a genetically elevated Lp(a) level was associated with CAVS independently of the presence of CAD. These findings support further research on the potential usefulness of Lp(a) cascade screening in CAVS.
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http://dx.doi.org/10.1001/jamacardio.2019.1581DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC6547086PMC
July 2019

How useful is 18F-FDG PET/CT in patients with suspected vascular graft infection?

J Nucl Cardiol 2020 02 25;27(1):303-304. Epub 2018 Jul 25.

Department of Nuclear Medicine, IUCPQ, Quebec, Canada.

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http://dx.doi.org/10.1007/s12350-018-1377-6DOI Listing
February 2020

Accuracy of PET/CT for detection of infective endocarditis: Where are we now?

J Nucl Cardiol 2019 06 15;26(3):936-938. Epub 2017 Nov 15.

Department of Nuclear Medicine, Institut universitaire de cardiologie et de pneumologie de Québec, Quebec, Canada.

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http://dx.doi.org/10.1007/s12350-017-1126-2DOI Listing
June 2019

Single CT for attenuation correction of rest/stress cardiac SPECT perfusion imaging.

J Nucl Cardiol 2018 04 17;25(2):616-624. Epub 2016 Nov 17.

Division of Cardiology, University of Ottawa Heart Institute, Ottawa, ON, Canada.

Common practice is to use separate CT scans acquired during rest and stress for attenuation correction of SPECT myocardial perfusion imaging (MPI). We evaluated using a single CT scan to correct both rest and stress SPECT scans. Studies from 154 patients were reprocessed using one CT acquired at stress to correct both rest and stress scans (1CT) and compared to correction of each scan with its own CT (2CT). Two expert readers independently read the images and determined summed stress (SSS), rest (SRS), and difference (SDS) scores. The correlation in SRS between 2CT and 1CT was r ≥ 0.88. The concordance in SDS was ≥0.84 (kappa ≥ 0.62). The mean SDS difference between 2CT and 1CT for the averaged observer was not significantly different from zero (p > 0.31). 1CT images had a small but significant increase in SRS and an increase in SDS variability. However, the mean SDS difference was similar to the mean inter-observer SDS difference for the 2CT approach (-0.08 vs -0.23, p = 0.46) and had less uncertainty (1.02 vs 2.05, p < 0.001). Thus, the differences between 1CT and 2CT are unlikely to be clinically significant, and the 1CT approach is feasible for SPECT MPI.
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http://dx.doi.org/10.1007/s12350-016-0720-zDOI Listing
April 2018

Role of radionuclide imaging for diagnosis of device and prosthetic valve infections.

World J Cardiol 2016 Sep;8(9):534-546

Jean-François Sarrazin, François Philippon, Department of Cardiology, Institut Universitaire de Cardiologie et Pneumologie de Québec, Laval University, Québec, QC G1V 4G5, Canada.

Cardiovascular implantable electronic device (CIED) infection and prosthetic valve endocarditis (PVE) remain a diagnostic challenge. Cardiac imaging plays an important role in the diagnosis and management of patients with CIED infection or PVE. Over the past few years, cardiac radionuclide imaging has gained a key role in the diagnosis of these patients, and in assessing the need for surgery, mainly in the most difficult cases. Both F-fluorodeoxyglucose positron emission tomography/computed tomography (F-FDG PET/CT) and radiolabelled white blood cell single-photon emission computed tomography/computed tomography (WBC SPECT/CT) have been studied in these situations. In their 2015 guidelines for the management of infective endocarditis, the European Society of Cardiology incorporated cardiac nuclear imaging as part of their diagnostic algorithm for PVE, but not CIED infection since the data were judged insufficient at the moment. This article reviews the actual knowledge and recent studies on the use of F-FDG PET/CT and WBC SPECT/CT in the context of CIED infection and PVE, and describes the technical aspects of cardiac radionuclide imaging. It also discusses their accepted and potential indications for the diagnosis and management of CIED infection and PVE, the limitations of these tests, and potential areas of future research.
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http://dx.doi.org/10.4330/wjc.v8.i9.534DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC5039355PMC
September 2016

Characterization of 3-Dimensional PET Systems for Accurate Quantification of Myocardial Blood Flow.

J Nucl Med 2017 Jan 18;58(1):103-109. Epub 2016 Aug 18.

National Cardiac PET Centre, University of Ottawa Heart Institute, Ottawa Ontario, Canada

Three-dimensional (3D) mode imaging is the current standard for PET/CT systems. Dynamic imaging for quantification of myocardial blood flow with short-lived tracers, such as Rb-chloride, requires accuracy to be maintained over a wide range of isotope activities and scanner counting rates. We proposed new performance standard measurements to characterize the dynamic range of PET systems for accurate quantitative imaging.

Methods: Rb or N-ammonia (1,100-3,000 MBq) was injected into the heart wall insert of an anthropomorphic torso phantom. A decaying isotope scan was obtained over 5 half-lives on 9 different 3D PET/CT systems and 1 3D/2-dimensional PET-only system. Dynamic images (28 × 15 s) were reconstructed using iterative algorithms with all corrections enabled. Dynamic range was defined as the maximum activity in the myocardial wall with less than 10% bias, from which corresponding dead-time, counting rates, and/or injected activity limits were established for each scanner. Scatter correction residual bias was estimated as the maximum cavity blood-to-myocardium activity ratio. Image quality was assessed via the coefficient of variation measuring nonuniformity of the left ventricular myocardium activity distribution.

Results: Maximum recommended injected activity/body weight, peak dead-time correction factor, counting rates, and residual scatter bias for accurate cardiac myocardial blood flow imaging were 3-14 MBq/kg, 1.5-4.0, 22-64 Mcps singles and 4-14 Mcps prompt coincidence counting rates, and 2%-10% on the investigated scanners. Nonuniformity of the myocardial activity distribution varied from 3% to 16%.

Conclusion: Accurate dynamic imaging is possible on the 10 3D PET systems if the maximum injected MBq/kg values are respected to limit peak dead-time losses during the bolus first-pass transit.
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http://dx.doi.org/10.2967/jnumed.116.174565DOI Listing
January 2017

Clinical interpretation standards and quality assurance for the multicenter PET/CT trial rubidium-ARMI.

J Nucl Med 2014 Jan 18;55(1):58-64. Epub 2013 Nov 18.

University of Ottawa Heart Institute, Ottawa, Ontario, Canada.

Unlabelled: Rubidium-ARMI ((82)Rb as an Alternative Radiopharmaceutical for Myocardial Imaging) is a multicenter trial to evaluate the accuracy, outcomes, and cost-effectiveness of low-dose (82)Rb perfusion imaging using 3-dimensional (3D) PET/CT technology. Standardized imaging protocols are essential to ensure consistent interpretation.

Methods: Cardiac phantom qualifying scans were obtained at 7 recruiting centers. Low-dose (10 MBq/kg) rest and pharmacologic stress (82)Rb PET scans were obtained in 25 patients at each site. Summed stress scores, summed rest scores, and summed difference scores (SSS, SRS, and SDS [respectively] = SSS-SRS) were evaluated using 17-segment visual interpretation with a discretized color map. All scans were coread at the core lab (University of Ottawa Heart Institute) to assess agreement of scoring, clinical diagnosis, and image quality. Scoring differences greater than 3 underwent a third review to improve consensus. Scoring agreement was evaluated with intraclass correlation coefficient (ICC-r), concordance of clinical interpretation, and image quality using κ coefficient and percentage agreement. Patient (99m)Tc and (201)Tl SPECT scans (n = 25) from 2 centers were analyzed similarly for comparison to (82)Rb.

Results: Qualifying scores of SSS = 2, SDS = 2, were achieved uniformly at all imaging sites on 9 different 3D PET/CT scanners. Patient scores showed good agreement between core and recruiting sites: ICC-r = 0.92, 0.77 for SSS, SDS. Eighty-five and eighty-seven percent of SSS and SDS scores, respectively, had site-core differences of 3 or less. After consensus review, scoring agreement improved to ICC-r = 0.97, 0.96 for SSS, SDS (P < 0.05). The agreement of normal versus abnormal (SSS ≥ 4) and nonischemic versus ischemic (SDS ≥ 2) studies was excellent: ICC-r = 0.90 and 0.88. Overall interpretation showed excellent agreement, with a κ = 0.94. Image quality was perceived differently by the site versus core reviewers (90% vs. 76% good or better; P < 0.05). By comparison, scoring agreement of the SPECT scans was ICC-r = 0.82, 0.72 for SSS, SDS. Seventy-six and eighty-eight percent of SSS and SDS scores, respectively, had site-core differences of 3 or less. Consensus review again improved scoring agreement to ICC-r = 0.97, 0.90 for SSS, SDS (P < 0.05).

Conclusion: (82)Rb myocardial perfusion imaging protocols were implemented with highly repeatable interpretation in centers using 3D PET/CT technology, through an effective standardization and quality assurance program. Site scoring of (82)Rb PET myocardial perfusion imaging scans was found to be in good agreement with core lab standards, suggesting that the data from these centers may be combined for analysis of the rubidium-ARMI endpoints.
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http://dx.doi.org/10.2967/jnumed.112.117515DOI Listing
January 2014

Usefulness of fluorine-18 positron emission tomography/computed tomography for identification of cardiovascular implantable electronic device infections.

J Am Coll Cardiol 2012 May;59(18):1616-25

Department of Medicine, Division of Cardiology, Institut universitaire de cardiologie et pneumologie de Québec, 2725 chemin Sainte-Foy, Québec City, Quebec, Canada.

Objectives: This study evaluated the usefulness of fluorodesoxyglucose marked by fluorine-18 ((18)F-FDG) positron emission tomography (PET) and computed tomography (CT) in patients with suspected cardiovascular implantable electronic device (CIED) infection.

Background: CIED infection is sometimes challenging to diagnose. Because extraction is associated with significant morbidity/mortality, new imaging modalities to confirm the infection and its dissemination would be of clinical value.

Methods: Three groups were compared. In Group A, 42 patients with suspected CIED infection underwent (18)F-FDG PET/CT. Positive PET/CT was defined as abnormal uptake along cardiac devices. Group B included 12 patients without infection who underwent PET/CT 4 to 8 weeks post-implant. Group C included 12 patients implanted for >6 months without infection who underwent PET/CT for another indication. Semi-quantitative ratio (SQR) was obtained from the ratio between maximal uptake and lung parenchyma uptake.

Results: In Group A, 32 of 42 patients with suspected CIED infection had positive PET/CT. Twenty-four patients with positive PET/CT underwent extraction with excellent correlation. In 7 patients with positive PET/CT, 6 were treated as superficial infection with clinical resolution. One patient with positive PET/CT but negative leukocyte scan was considered false positive due to Dacron pouch. Ten patients with negative-PET/CT were treated with antibiotics and none has relapsed at 12.9 ± 1.9 months. In Group B, patients had mild uptake seen at the level of the connector. There was no abnormal uptake in Group C patients. Median SQR was significantly higher in Group A (A = 2.02 vs. B = 1.08 vs. C = 0.57; p < 0.001).

Conclusions: PET/CT is useful in differentiating between CIED infection and recent post-implant changes. It may guide appropriate therapy.
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http://dx.doi.org/10.1016/j.jacc.2011.11.059DOI Listing
May 2012