- Email: [email protected]
COMPARISON OF LEFT VENTRICULAR MAXIMUM STRAIN TO EJECTION FRACTION MEASUREMENTS FROM CONVENTIONAL CINE CARDIAC MAGNETIC RESONANCE IMAGES
S300
anatomical landmarks than other organs. In this context, the aim of this study was to develop a method based on cine MRI and finite element modeling of the heart to evaluate mechanical properties changes within the myocardium in children receiving doxorubicin therapy for leukemia. METHODS: We prospectively included 26 cancer survivors which have previously undergone an doxorubicin-based chemotherapy for childhood leukemia and 6 healthy volunteers. Within cancer survivors group, eight volunteers (n¼8) were included in the standard risk (SR) group and eighteen volunteers (n¼18) were included in the high risk (HR) group, based on a risk index related to the severity of the pathology and administered doxorubicin dose. Segmentation was done at the mid-ventricular level in short-axis, 2-chamber and 4chamber views, where strains and stresses were estimated using either linear or cumulative technique and compared between groups. Linear technique required only the first and last phase of the given cardiac interval in order to estimate strains and stresses. However, cumulative technique required each phase to be segmented. We used an isotropic hyperplastic model with a discrete distribution of Young’s Modulus. RESULTS: Cancer survivors had lower cumulative strains and stresses compared to healthy volunteers during diastolic relaxation in 2-chamber, 4-chamber and short-axis views. Strains and stresses differences between SR and HR groups were small and present only in few myocardial segments. While the linear technique is more realistic because the hyperelasticity is taken into account, the cumulative technique is more robust due mesh stabilization at each phase of the cardiac interval, which is more appropriated for large displacements. CONCLUSION: Our new skeleton-based technique provided robust results and accurate tracking of myocardial tissue for further quantification of apparent strains and mechanical stresses. The apparent strains and stresses were significantly lower in doxorubicin-treated cancer survivors, which may indicate a reduction in myocardial contractile function. Taking into account the non-linear myocardial displacements through this cumulative-based estimation of strains and stresses help in detecting any early alterations in myocardial tissue properties. CIHR Team grant, Cole Foundation, NSERC 410 EARLY DETECTION OF DOXORUBICIN INDUCED CARDIOTOXICITY IN THE SWINE BY CARDIAC MRI C Balosetti, D Curnier, H Heon, N Dahdah, F Cheriet, M Friedrich, D Perie Montréal, Québec BACKGROUND:
Cancer chemotherapy is an effective treatment to treat cancer in both adults and children. However, the associated cardiotoxicity of doxorubicin is a well-known serious side effect leading to long-term morbidity. The objectives of this study were to simulate doxorubicin-induced cardiotoxicity in the miniature swine and to assess the utility
Canadian Journal of Cardiology Volume 32 2016
of a novel cardiovascular MR (CMR) imaging protocol to detect this cardiotoxicity. METHODS: Female Yucatan miniature swine received either a chemotherapy treatment using doxorubicin (doxorubicin group, n¼5, 5 doses of 75mg/m2, 3 weeks interval) or saline (control group, n¼2). Three MRI scans and three echocardiography exams were performed before the 1st injection (A1), after the 4th injection (cumulative dose 300mg/m2) (A2), and 3 weeks after the last injection (A3). Hematology lab results, clinical signs, echocardiography measures and CMR parameters were compared between groups and acquisitions. RESULTS: The miniature swine from the doxorubicin group developed alopecia, suffered from diarrhea some days after each doxorubicin infusion and presented decreased white blood cells and platelets. In echocardiography, reductions of shortening fraction, ejection fraction and aortic blood flow were apparent at the last exam in the doxorubicin group, while results remained constant in the control group. From cineCMR, left and right ventricles areas, lengths, thicknesses and left ventricle torsion presented similar patterns along the cardiac cycle, but with different amplitudes between acquisitions and groups. For the left ventricle end-diastolic cumulative displacements, the curve amplitude increased from A1 to A3 in the control group while it remains constant in the doxorubicin group. Cumulative von-Mises strain decreased at A3 in systole and late diastole in the doxorubicin group but stayed constant in the control group. Native T1 decreased from A1 to A3 in the control group. T1 post gadolinium decreased from A1 to A3 in both control and doxorubicin groups. T2 decreased from A1 to A3 in the doxorubicin group. CONCLUSION: The CMR parameters we investigated in the miniature swine therapeutic model with doxorobucin was able discriminate treated animals from controls. Differences were detectible earlier than onset of classical echocardiographic changes. Translating these observations to personalized medicine approach could be the premise for the oncologist to know accurately when the treatment just starts to have deleterious effect on myocardium instead of just observing that the heart was damaged by doxorubicin. The miniature swine therapeutic model would help cardiologists and oncologists to develop early, specific and even preventive therapeutic interventions. Fonds de Recherche du Québec en Nature et Technologies, Natural Sciences and Engineering Research Council of Canada 411 COMPARISON OF LEFT VENTRICULAR MAXIMUM STRAIN TO EJECTION FRACTION MEASUREMENTS FROM CONVENTIONAL CINE CARDIAC MAGNETIC RESONANCE IMAGES J Luan, R Thompson, I Paterson, K Punithakumar, M Noga Edmonton, Alberta BACKGROUND:
Left ventricular systolic heart function is frequently evaluated by measuring left ventricular ejection
Abstracts
S301
fraction (LVEF), based on conventional cine cardiac MRI (CMR). Endocardial strain has been proposed as an alternative measure for evaluating systolic dysfunction. The objective is to compare strain from CMR analysis with LVEF as an alternative, more robust measure of systolic function. METHODS: 127 patients at risk for heart failure and normal volunteers were recruited for CMR scanning. Two, 3 and 4 chamber long axis (LA) longitudinal strains as well as short axis (SA) circumferential strains were calculated from the length change of LV endocardial contours on cine MR. Global circumferential strain was calculated from the global LV stack as was average circumferential strain from three representative (basal, mid and apical) short axis oblique (SAO) slices. Unweighted average strains were calculated for the sets: 2 and 4 chamber, 3 slices SA and 4 chamber, and 3 slices SA and 2 chamber. A weighted average strain with the relative weights of 50% 3 slices SA, 25% 4 chamber and 25% 2 chamber strains were also calculated. Pearson’s correlation and Bland-Altman analysis were used to assess strain’s correlation to ejection fraction. Ejection fraction was measured by an independent expert user manually tracing SAO contours on Siemens Argus software. Receiver operating characteristic (ROC) curve analysis was used to determine maximum strain’s ability to detect systolic dysfunction. Maximum strain from global SA, 3 slices SA and LV 4 chamber scans from 10 random subjects were assessed by two observers for inter-observer studies. The intra-class correlation coefficient was used to assess inter-observer reliability. RESULTS: Table 1 shows the results for the Pearson’s correlation. Furthermore, when we compared the 3 slices SA with global SA maximum strain using Bland-Altman analysis, we found a bias of 0.11 and limits of agreement from -3.4 to 3.2. LVEF as a function of global and 3 slices SA strains are LVEF¼-1.98(Xglobal)+7.64 and LVEF¼-2.02(X3slice)+6.59. The inter-observer intra-class correlation coefficient is 0.88 for global SA, 0.54 for 3 slices SA and 0.71 for LV 4 chamber strains. The area under the ROC curve for global SA and 3 slices SA are 0.97 and 0.96 respectively. Absolute value maximum strain cutoffs for systolic dysfunction are strain<22.39 for global SA and strain<22.86 for 3 slices SA. CONCLUSION: Maximum strain measurements from cine CMR SA scans correlate well with LVEF to provide a reliable alternative measure of systolic function.
Scan view
Table 1 Pearson’s correlation coefficients Pearson's r compared with LVEF (absolute value)
Short axis global stack
0.93
Short axis 3 representative
0.90
3 slices, 4 and 2 chamber average
0.84
3 slices and 4 chamber average
0.82
3 slices and 2 chamber average
0.80
3 chamber
0.71
2 and 4 chamber average
0.61
4 chamber
0.58
2 chamber
0.48
Servier Canada Inc.
Canadian Cardiovascular Society (CCS) ePoster CLINICAL QUALITY IMPROVEMENT Monday, October 24, 2016 412 EFFICACY AND SAFETY OF INHALED ANESTHETIC FOR POSTOPERATIVE SEDATION DURING MECHANICAL VENTILATION IN ADULT CARDIAC SURGERY PATIENTS: A SYSTEMATIC REVIEW AND META-ANALYSIS J Spence, E Belley-Cote, K Ma, S Donald, J Centofanti, S Hussain, S Gupta, P Devereaux, R Whitlock Dundas, Ontario BACKGROUND:
Volatile anesthetics have pharmacokinetic and pharmacodynamic properties that are ideally suited to the cardiac surgical ICU. Since the development of the Anesthetic Conserving Device (AnaCONDaTM, Sedana Medical, Uppsala, Sweden), their use in this setting has increased. Randomized trials have shown it to be associated with shorter time to extubation and, in the cardiac surgery population, lower postoperative biomarker peak, suggesting a potential therapeutic benefit. Existing studies have been underpowered to show an impact on ICU or hospital length-of-stay (LOS), major adverse cardiovascular events (MACE) or mortality. As such, we undertook a systematic review and meta-analysis, emphasizing their efficacy and safety in the context of a fasttrack approach to postoperative care. METHODS: We searched MEDLINE, EMBASE, Cochrane Library, ISI Web of Science, and Clinicaltrials.gov for randomized controlled trials in postoperative, adult, cardiac surgical patients comparing inhaled anesthetic with intravenous sedation. Crossover studies were excluded. No language or date of publication restrictions were applied. Primary outcomes of interest were time to extubation, ICU LOS, and hospital LOS. Secondary outcomes included postoperative troponin peak, MACE, and kidney injury, effectiveness of sedation, and inpatient costs. References were screened independently and in duplicate, and studies deemed to be potentially relevant were evaluated for inclusion by full-text review. Risk of bias was assessed using the Cochrane tool. Data were meta-analysed using RevMan 5.3 software (Cochrane Collaboration, Oxford, United Kingdom) and the overall quality of evidence for each outcome was evaluated using the GRADE framework. RESULTS: 8 studies including 610 patients met eligibility criteria. Studies were assessed as having a high risk of bias because blinding and per protocol analysis. Outcomes are summarized in Figure 1 below. Volatile anesthetic sedation was associated with a shorter time to extubation, both after ICU admission (SMD 76 minutes, 95% CI 150 - 2, very low quality evidence) and discontinuation of sedation (SMD 74 minutes, 95% CI 126 - 23, moderate quality evidence). There was no difference in ICU or hospital LOS. Peak troponin levels were significantly lower (SMD 0.72ng/mL, 95% 1.2 0.2, high quality evidence) in the volatile anesthetic group.
anatomical landmarks than other organs. In this context, the aim of this study was to develop a method based on cine MRI and finite element modeling of the heart to evaluate mechanical properties changes within the myocardium in children receiving doxorubicin therapy for leukemia. METHODS: We prospectively included 26 cancer survivors which have previously undergone an doxorubicin-based chemotherapy for childhood leukemia and 6 healthy volunteers. Within cancer survivors group, eight volunteers (n¼8) were included in the standard risk (SR) group and eighteen volunteers (n¼18) were included in the high risk (HR) group, based on a risk index related to the severity of the pathology and administered doxorubicin dose. Segmentation was done at the mid-ventricular level in short-axis, 2-chamber and 4chamber views, where strains and stresses were estimated using either linear or cumulative technique and compared between groups. Linear technique required only the first and last phase of the given cardiac interval in order to estimate strains and stresses. However, cumulative technique required each phase to be segmented. We used an isotropic hyperplastic model with a discrete distribution of Young’s Modulus. RESULTS: Cancer survivors had lower cumulative strains and stresses compared to healthy volunteers during diastolic relaxation in 2-chamber, 4-chamber and short-axis views. Strains and stresses differences between SR and HR groups were small and present only in few myocardial segments. While the linear technique is more realistic because the hyperelasticity is taken into account, the cumulative technique is more robust due mesh stabilization at each phase of the cardiac interval, which is more appropriated for large displacements. CONCLUSION: Our new skeleton-based technique provided robust results and accurate tracking of myocardial tissue for further quantification of apparent strains and mechanical stresses. The apparent strains and stresses were significantly lower in doxorubicin-treated cancer survivors, which may indicate a reduction in myocardial contractile function. Taking into account the non-linear myocardial displacements through this cumulative-based estimation of strains and stresses help in detecting any early alterations in myocardial tissue properties. CIHR Team grant, Cole Foundation, NSERC 410 EARLY DETECTION OF DOXORUBICIN INDUCED CARDIOTOXICITY IN THE SWINE BY CARDIAC MRI C Balosetti, D Curnier, H Heon, N Dahdah, F Cheriet, M Friedrich, D Perie Montréal, Québec BACKGROUND:
Cancer chemotherapy is an effective treatment to treat cancer in both adults and children. However, the associated cardiotoxicity of doxorubicin is a well-known serious side effect leading to long-term morbidity. The objectives of this study were to simulate doxorubicin-induced cardiotoxicity in the miniature swine and to assess the utility
Canadian Journal of Cardiology Volume 32 2016
of a novel cardiovascular MR (CMR) imaging protocol to detect this cardiotoxicity. METHODS: Female Yucatan miniature swine received either a chemotherapy treatment using doxorubicin (doxorubicin group, n¼5, 5 doses of 75mg/m2, 3 weeks interval) or saline (control group, n¼2). Three MRI scans and three echocardiography exams were performed before the 1st injection (A1), after the 4th injection (cumulative dose 300mg/m2) (A2), and 3 weeks after the last injection (A3). Hematology lab results, clinical signs, echocardiography measures and CMR parameters were compared between groups and acquisitions. RESULTS: The miniature swine from the doxorubicin group developed alopecia, suffered from diarrhea some days after each doxorubicin infusion and presented decreased white blood cells and platelets. In echocardiography, reductions of shortening fraction, ejection fraction and aortic blood flow were apparent at the last exam in the doxorubicin group, while results remained constant in the control group. From cineCMR, left and right ventricles areas, lengths, thicknesses and left ventricle torsion presented similar patterns along the cardiac cycle, but with different amplitudes between acquisitions and groups. For the left ventricle end-diastolic cumulative displacements, the curve amplitude increased from A1 to A3 in the control group while it remains constant in the doxorubicin group. Cumulative von-Mises strain decreased at A3 in systole and late diastole in the doxorubicin group but stayed constant in the control group. Native T1 decreased from A1 to A3 in the control group. T1 post gadolinium decreased from A1 to A3 in both control and doxorubicin groups. T2 decreased from A1 to A3 in the doxorubicin group. CONCLUSION: The CMR parameters we investigated in the miniature swine therapeutic model with doxorobucin was able discriminate treated animals from controls. Differences were detectible earlier than onset of classical echocardiographic changes. Translating these observations to personalized medicine approach could be the premise for the oncologist to know accurately when the treatment just starts to have deleterious effect on myocardium instead of just observing that the heart was damaged by doxorubicin. The miniature swine therapeutic model would help cardiologists and oncologists to develop early, specific and even preventive therapeutic interventions. Fonds de Recherche du Québec en Nature et Technologies, Natural Sciences and Engineering Research Council of Canada 411 COMPARISON OF LEFT VENTRICULAR MAXIMUM STRAIN TO EJECTION FRACTION MEASUREMENTS FROM CONVENTIONAL CINE CARDIAC MAGNETIC RESONANCE IMAGES J Luan, R Thompson, I Paterson, K Punithakumar, M Noga Edmonton, Alberta BACKGROUND:
Left ventricular systolic heart function is frequently evaluated by measuring left ventricular ejection
Abstracts
S301
fraction (LVEF), based on conventional cine cardiac MRI (CMR). Endocardial strain has been proposed as an alternative measure for evaluating systolic dysfunction. The objective is to compare strain from CMR analysis with LVEF as an alternative, more robust measure of systolic function. METHODS: 127 patients at risk for heart failure and normal volunteers were recruited for CMR scanning. Two, 3 and 4 chamber long axis (LA) longitudinal strains as well as short axis (SA) circumferential strains were calculated from the length change of LV endocardial contours on cine MR. Global circumferential strain was calculated from the global LV stack as was average circumferential strain from three representative (basal, mid and apical) short axis oblique (SAO) slices. Unweighted average strains were calculated for the sets: 2 and 4 chamber, 3 slices SA and 4 chamber, and 3 slices SA and 2 chamber. A weighted average strain with the relative weights of 50% 3 slices SA, 25% 4 chamber and 25% 2 chamber strains were also calculated. Pearson’s correlation and Bland-Altman analysis were used to assess strain’s correlation to ejection fraction. Ejection fraction was measured by an independent expert user manually tracing SAO contours on Siemens Argus software. Receiver operating characteristic (ROC) curve analysis was used to determine maximum strain’s ability to detect systolic dysfunction. Maximum strain from global SA, 3 slices SA and LV 4 chamber scans from 10 random subjects were assessed by two observers for inter-observer studies. The intra-class correlation coefficient was used to assess inter-observer reliability. RESULTS: Table 1 shows the results for the Pearson’s correlation. Furthermore, when we compared the 3 slices SA with global SA maximum strain using Bland-Altman analysis, we found a bias of 0.11 and limits of agreement from -3.4 to 3.2. LVEF as a function of global and 3 slices SA strains are LVEF¼-1.98(Xglobal)+7.64 and LVEF¼-2.02(X3slice)+6.59. The inter-observer intra-class correlation coefficient is 0.88 for global SA, 0.54 for 3 slices SA and 0.71 for LV 4 chamber strains. The area under the ROC curve for global SA and 3 slices SA are 0.97 and 0.96 respectively. Absolute value maximum strain cutoffs for systolic dysfunction are strain<22.39 for global SA and strain<22.86 for 3 slices SA. CONCLUSION: Maximum strain measurements from cine CMR SA scans correlate well with LVEF to provide a reliable alternative measure of systolic function.
Scan view
Table 1 Pearson’s correlation coefficients Pearson's r compared with LVEF (absolute value)
Short axis global stack
0.93
Short axis 3 representative
0.90
3 slices, 4 and 2 chamber average
0.84
3 slices and 4 chamber average
0.82
3 slices and 2 chamber average
0.80
3 chamber
0.71
2 and 4 chamber average
0.61
4 chamber
0.58
2 chamber
0.48
Servier Canada Inc.
Canadian Cardiovascular Society (CCS) ePoster CLINICAL QUALITY IMPROVEMENT Monday, October 24, 2016 412 EFFICACY AND SAFETY OF INHALED ANESTHETIC FOR POSTOPERATIVE SEDATION DURING MECHANICAL VENTILATION IN ADULT CARDIAC SURGERY PATIENTS: A SYSTEMATIC REVIEW AND META-ANALYSIS J Spence, E Belley-Cote, K Ma, S Donald, J Centofanti, S Hussain, S Gupta, P Devereaux, R Whitlock Dundas, Ontario BACKGROUND:
Volatile anesthetics have pharmacokinetic and pharmacodynamic properties that are ideally suited to the cardiac surgical ICU. Since the development of the Anesthetic Conserving Device (AnaCONDaTM, Sedana Medical, Uppsala, Sweden), their use in this setting has increased. Randomized trials have shown it to be associated with shorter time to extubation and, in the cardiac surgery population, lower postoperative biomarker peak, suggesting a potential therapeutic benefit. Existing studies have been underpowered to show an impact on ICU or hospital length-of-stay (LOS), major adverse cardiovascular events (MACE) or mortality. As such, we undertook a systematic review and meta-analysis, emphasizing their efficacy and safety in the context of a fasttrack approach to postoperative care. METHODS: We searched MEDLINE, EMBASE, Cochrane Library, ISI Web of Science, and Clinicaltrials.gov for randomized controlled trials in postoperative, adult, cardiac surgical patients comparing inhaled anesthetic with intravenous sedation. Crossover studies were excluded. No language or date of publication restrictions were applied. Primary outcomes of interest were time to extubation, ICU LOS, and hospital LOS. Secondary outcomes included postoperative troponin peak, MACE, and kidney injury, effectiveness of sedation, and inpatient costs. References were screened independently and in duplicate, and studies deemed to be potentially relevant were evaluated for inclusion by full-text review. Risk of bias was assessed using the Cochrane tool. Data were meta-analysed using RevMan 5.3 software (Cochrane Collaboration, Oxford, United Kingdom) and the overall quality of evidence for each outcome was evaluated using the GRADE framework. RESULTS: 8 studies including 610 patients met eligibility criteria. Studies were assessed as having a high risk of bias because blinding and per protocol analysis. Outcomes are summarized in Figure 1 below. Volatile anesthetic sedation was associated with a shorter time to extubation, both after ICU admission (SMD 76 minutes, 95% CI 150 - 2, very low quality evidence) and discontinuation of sedation (SMD 74 minutes, 95% CI 126 - 23, moderate quality evidence). There was no difference in ICU or hospital LOS. Peak troponin levels were significantly lower (SMD 0.72ng/mL, 95% 1.2 0.2, high quality evidence) in the volatile anesthetic group.