Pressure-Volume Relationship By Pharmacological Stress Cardiovascular Magnetic Resonance

Author(s):  
Antonella Meloni ◽  
Antonio De Luca ◽  
Cinzia Nugara ◽  
Maria Vaccaro ◽  
Camilla Cavallaro ◽  
...  

Abstract Background. The variation between rest and peak stress end-systolic pressure-volume relation (ΔESPVR) is an index of myocardial contractility, easily obtained during routine stress echocardiography and never tested during dipyridamole stress-cardiac magnetic resonance (CMR). We assessed the ΔESPVR index in patients with known/suspected coronary artery disease (CAD) who underwent dipyridamole stress-CMR.Methods. One-hundred consecutive patients (24 females, 63.76±10.17 years) were considered. ESPVR index was evaluated at rest and stress from raw measurement of systolic arterial pressure and end-systolic volume by biplane Simpson’s method. Results. The ΔESPVR index showed a good inter-operator reproducibility. Mean ΔESPVR index was 0.48±1.45 mmHg/mL/m2. ΔESPVR index was significantly lower in males than in females. ΔESPVR index was not correlated to rest left ventricular end-diastolic volume index or ejection fraction. Forty-six of 85 patients had myocardial fibrosis detected by the late gadolinium enhancement technique and they showed significantly lower ΔESPVR values. An abnormal stress CMR was found in 25 patients and they showed significantly lower ΔESPVR values. During a mean follow-up of 56.34±30.04 months, 24 cardiovascular events occurred. At receiver-operating characteristic curve analysis, a ΔESPVR<0.02 mmHg/mL/m2 predicted the presence of future cardiac events with a sensitivity of 0.79 and a specificity of 0.68. Conclusions. The noninvasive assessment of the ΔESPVR index during a dipyridamole stress-CMR exam is feasible and reproducible. The ΔESPVR index was independent from rest LV dimensions and function and can be used for a comparative assessment of patients with different diseases. ΔESPVR by CMR can be a useful and simple marker for additional prognostic stratification.

2019 ◽  
Vol 40 (Supplement_1) ◽  
Author(s):  
A De Luca ◽  
A Meloni ◽  
C Nugara ◽  
C Cappelletto ◽  
G Aquaro ◽  
...  

Abstract Background The variation between rest and peak stress end-systolic pressure-volume relation (ESPVR; the Suga index) is easily obtained during routine stress echocardiography and has been established as a reasonably load-independent index of myocardial contractile performance that provides prognostic information above and beyond regional wall motion. Purpose This is the first study assessing the delta rest-stress ESPVR (DESPVR) by stress Cardiovascular Magnetic Resonance (CMR). Methods Eighty-five consecutive patients (19 females, main age 62.99±9.26 years) who underwent dipyridamole stress-CMR in a high volume CMR Laboratory were considered. The ESPVR was evaluated at rest and peak stress from raw measurement of systolic arterial pressure by cuff sphygmomanometer and end-systolic volume by biplane Simpson method. Results Mean ESPVR index at rest and peak stress was, respectively, 4.52±2.26 mmHg/mL/m2 and 4.62±2.32 mmHg/mL/m2 and mean DESPVR was 0.11±1.19 mmHg/mL/m2. DESPVR was not associated to age or sex. An inverse relationship between rest left ventricular end-diastolic volume index (LVEDVI) and both rest and peak ESPVR was present (R=-0.805 P<0.0001 and R=-0.795 P<0.0001, respectively), but it was absent when the DESPVR was considered (R=0.170 P=0.121). An abnormal stress CMR was found in 22 patients and the DESPVR was comparable between patients with normal and abnormal stress exam. During a median follow-up of 60.62 months (IQ range 36.78 months), 27 cardiovascular events occurred: 3 deaths, 1 ventricular arrhythmias, 9 coronary syndromes, 14 heart failure hospitalization. At receiver-operating characteristic (ROC) curve analysis, a DESPVR<0.009 predicted the presence of future cardiac events with a sensitivity of 0.70 and a specificity of 0.64 (P=0.049). Conclusions We showed for the first time that dipyridamole stress CMR can be used for the assessment of DESPVR. DESPVR was shown to be independent from chamber size and, as a consequence, can be used for a comparative assessment of patients with different diseases. DESPVR by CMR can provide a prognostic stratification and the optimal cutoff for relevant events was 0.009.


2020 ◽  
Vol 90 (2) ◽  
Author(s):  
Gian Marco Rosa ◽  
Andreina D'Agostino ◽  
Stefano Giovinazzo ◽  
Giovanni La Malfa ◽  
Paolo Fontanive ◽  
...  

Echocardiography of right ventricular (RV)-arterial coupling obtained by the estimation of the ratio of the longitudinal annular systolic excursion of the tricuspid annular plane and pulmonary artery systolic pressure (TAPSE/PASP) has been found to be a remarkable prognostic indicator in patients with HF. Our aim was to evaluate the impact of TAPSE, PASP and their ratio in the prognostic stratification of outpatients with HF aged ≥70 years and reduced to mid-range ejection fraction (EF). A complete echocardiographic examination was performed in 400 outpatients with chronic HF and left ventricular (LV) EF ≤50% who averaged 77 years in age. During a median follow-up period of 25 months (interquartile range: 8-46), there were 135 cardiovascular deaths. Two different Cox regression models were evaluated, one including TAPSE and PASP, separately, and the other with TAPSE/PASP. In the first model, LV end-systolic volume index, age, no angiotensin converting enzyme (ACE) inhibitor use, TAPSE, PASP and gender were found to be independently associated with the outcome after adjustment for demographics, clinical, biochemical, echocardiographic data. In the second model, TAPSE/PASP resulted the most important independent predictor of outcome (hazard ratio [HR]:0.07, p<0.0001) followed by LV end-systolic volume index, no ACE inhibitor use, age and gender. The use of the variable TASPE/PASP improved the predictive value of the new multivariable model (area under the curve [AUC] of 0.74 vs AUC of 0.71; p<0.05). TASPE/PASP improved the net reclassification (NRI = 14.7%; p<0.01) and the integrated discrimination (IDI = 0.04; p<0.01). In conclusion, the study findings showed that assessment of RV-arterial coupling by TAPSE/PASP was of major importance to assess the prognosis of patients with chronic HF and LV EF ≤50% aged ≥70 years.


Author(s):  
Jay Ramchand ◽  
Pooja Podugu ◽  
Nancy Obuchowski ◽  
Serge C. Harb ◽  
Michael Chetrit ◽  
...  

Background Left ventricular non‐compaction remains a poorly described entity, which has led to challenges of overdiagnosis. We aimed to evaluate if the presence of a thin compacted myocardial layer portends poorer outcomes in individuals meeting cardiac magnetic resonance criteria for left ventricular non‐compaction . Methods and Results This was an observational, retrospective cohort study involving individuals selected from the Cleveland Clinic Foundation cardiac magnetic resonance database (N=26 531). Between 2000 and 2018, 328 individuals ≥12 years, with left ventricular non‐compaction or excessive trabeculations based on the cardiac magnetic resonance Petersen criteria were included. The cohort comprised 42% women, mean age 43 years. We assessed the predictive ability of myocardial thinning for the primary composite end point of major adverse cardiac events (composite of all‐cause mortality, heart failure hospitalization, left ventricular assist device implantation/heart transplant, ventricular tachycardia, or ischemic stroke). At mean follow‐up of 3.1 years, major adverse cardiac events occurred in 102 (31%) patients. After adjusting for comorbidities, the risk of major adverse cardiac events was nearly doubled in the presence of significant compacted myocardial thinning (hazard ratio [HR], 1.88 [95% CI, 1.18‒3.00]; P =0.016), tripled in the presence of elevated plasma B‐type natriuretic peptide (HR, 3.29 [95% CI, 1.52‒7.11]; P =0.006), and increased by 5% for every 10‐unit increase in left ventricular end‐systolic volume (HR, 1.01 [95% CI, 1.00‒1.01]; P =0.041). Conclusions The risk of adverse clinical events is increased in the presence of significant compacted myocardial thinning, an elevated B‐type natriuretic peptide or increased left ventricular dimensions. The combination of these markers may enhance risk assessment to minimize left ventricular non‐compaction overdiagnosis whilst facilitating appropriate diagnoses in those with true disease.


2020 ◽  
Vol 41 (Supplement_2) ◽  
Author(s):  
A Gabaldon-Perez ◽  
C Bonanad ◽  
V Marcos-Garces ◽  
J Gavara ◽  
H Merenciano-Gonzalez ◽  
...  

Abstract Background In recent guidelines, non-invasive imaging techniques play a pivotal role in the management of chronic coronary syndrome (CCS). The elderly represent a large percentage of our routine CCS population and risk stratification in this scenario is challenging. The potential of vasodilator stress cardiovascular magnetic resonance (vs-CMR) for this purpose is unknown. Purpose We explored the prognostic value of the ischemic burden, as derived from vs-CMR, in elderly patients with known or suspected CCS. Methods From the general cohort of 6389 patients with known or suspected CCS submitted to undergo vs-CMR in our health department from 2001 to 2016, we performed a subanalysis of the 1225 patients &gt;70 year-old (mean age 77±5 years, 51% male). Clinical and vs-CMR characteristics were prospectively recorded. The ischemic burden (at stress first-pass perfusion imaging) was computed (using the 17-segment model). The occurrence of major adverse cardiac events (MACE) defined as all-cause death and/or non-fatal myocardial infarction (whichever occurred first) was retrospectively revised using the electronic regional health system registry. Results During a median follow-up of 2.7 years, 203 MACEs were registered (17%). Age (77±4 vs. 76±5 years) was not significantly different in patients with and without MACE. Larger left ventricular (LV) end-diastolic and end-systolic volume indexes, more depressed LV ejection fraction, more extensive areas with late gadolinium enhancement and ischemic burden were detected in patients with MACE (p&lt;0.001 for all comparisons). In non-revascularized patients (n=1118), the MACE rate ranged from 13% (in patients with 0–1 ischemic segments) to 35% (in those with &gt;8 ischemic segments, p&lt;0.001 for the trend). In the small subset of revascularized patients (n=107), revascularization exerted a non-significant protective effect only in patients with extensive ischemic burden (&gt;5 segments). Conclusions Vasodilator stress CMR represents a valuable tool to stratify risk in elderly patients with known or suspected CCS and might be helpful to guide decision-making. Figure 1 Funding Acknowledgement Type of funding source: None


2020 ◽  
Vol 41 (Supplement_2) ◽  
Author(s):  
C Czimbalmos ◽  
C Nardocci ◽  
E Deetjen ◽  
L Szabo ◽  
Z Dohy ◽  
...  

Abstract   Differentiation between hypertrophic cardiomyopathy (HCM) patients and healthy athletes (HA) is a common clinical conundrum. We aimed to analyze cardiac magnetic resonance (CMR) characteristics of HA, sedentary HCM and athletic HCM patients and to determine CMR parameters which can help to diagnose HCM in athletes. Male sedentary HCM patients with slightly elevated maximal end-diastolic wall thickness (EDWT 13–18 mm, n=40, 47.6±14.7y) and HA (n=30, 27.5±5.6y) were consecutively enrolled. Additionally, athletes with HCM were enrolled (n=16, 29.6±13.4 y), where a comprehensive investigation confirmed the diagnosis of HCM. We determined conventional CMR parameters (left ventricular (LV) ejection fraction (EF), end-diastolic (EDVi) and end-systolic volume index, mass index (Mi)), derived parameters such as EDWT/LVEDVi, LVM/LVEDV ratio and strain parameters such as global longitudinal (GLS), radial (GRS) and circumferential strain (GCS), SD of peak LS and CS using feature tracking. Presence of late gadolinium enhancement (LGE) was also determined. CMR parameters representing LV hypertrophy pattern or LV function were analyzed using a logistic regression to detect the best CMR parameters to predict HCM in athletes. To differentiate between HA and athletes with HCM optimal cut-off values for CMR parameters were calculated using receiver operating curve analysis. Comparing the three groups significant differences were found regarding conventional and derived CMR parameters and strain values. None of the HA showed LGE, 75% of athletic HCM and 82% of sedentary HCM patients showed LGE. The univariate regression model showed that LVEF, EDWT, EDWT/LVMi, LVM/LVEDV, GCS, GRS, SD of peak LS and CS are determinants of the diagnosis of HCM among athletes. Multivariate regression revealed that EDWT/LVMi and GCS are independent disease predictors in athletes (p&lt;0.05). Cut-off value for GCS ≤−32.5 and for EDWT/LVEDVi &gt;0.126 discriminate athletic HCM from HA with a sensitivity of 81.3 and 87.5% (AUC 0.93), and a specificity of 96.7 and 83.3% (AUC 0.95), respectively (Figure 1). CMR characteristics of sedentary and athletic HCM may differ, therefore establishing diagnostic parameters based on comparison between athletic HCM and HA is essential. CMR based strain and derived parameters may help to differentiate between physiological and pathological left ventricular hypertrophy in athletes. Figure 1 Funding Acknowledgement Type of funding source: Public grant(s) – National budget only. Main funding source(s): National Research, Development and Innovation Office of Hungary (NKFIA) and National Research, Development and Innovation Office (NFKIH) of Hungary.


2021 ◽  
Vol 11 ◽  
pp. 33
Author(s):  
Afsaneh Maddah Safaei ◽  
Tara Molanaie Kamangar ◽  
Sanaz Asadian ◽  
Nahid Rezaeian ◽  
Ebrahim Esmati ◽  
...  

Objectives: Many patients with breast cancer (BC) require cardiotoxic anthracycline-based chemotherapy. We intended to assess the early cardiotoxic effects of doxorubicin utilizing cardiac magnetic resonance (CMR) imaging. Material and Methods: Forty-nine patients including 21 otherwise healthy females with BC at a mean age (±SD) of 47.62 ± 9.07 years and 28 normal controls at a mean age (±SD) of 45.18 ± 4.29 years were recruited. They underwent CMR and transthoracic echocardiography at baseline and 7 days after four biweekly cycles of doxorubicin and cyclophosphamide. Biventricular functional, volumetric, global strain, and tissue characterization findings were analyzed and compared with those of 28 controls. Results: In post-chemotherapy CMR, 4 patients (19.04%), three symptomatic and one asymptomatic, exhibited evidence of doxorubicin cardiotoxicity. Significant differences in biventricular ejection fraction, left ventricular end-systolic volume index, and all 3D global strain values were noted after chemotherapy in comparison with the baseline (all P < 0.05). More than half of the study population showed a significant change in all right ventricular global strain values. One patient (4.76%) exhibited evidence of diffuse myocardial edema in post-chemotherapy CMR, and 3 patients (14.28%) showed myocardial fibrosis. The study participants were clinically followed up for 4–10 months (mean = 7 months). Overall, 8 patients (38.09%) complained of dyspnea on exertion and fatigue on follow-up. None of the CMR markers was associated with the development of symptoms. Conclusion: Our investigation revealed striking changes in CMR parameters in the follow-up of BC patients treated with cardiotoxic chemotherapy. These exclusive CMR features assist in the early initiation of preventive cardiac strategies.


1999 ◽  
Vol 277 (5) ◽  
pp. H1906-H1913 ◽  
Author(s):  
Bo Yang ◽  
Douglas F. Larson ◽  
Ronald Watson

Our study compared left ventricular (LV) function between senescent and young adult mice through in situ pressure-volume loop analysis. Two groups of mice ( n = 9 each), 6-mo-old and 16-mo-old (senescent) mice, were anesthetized with urethan and α-chloralose, and their LV were instrumented with a Millar 1.4-Fr conductance micromanometer catheter for the acquisition of the pressure-volume loops. The senescent mice had a significantly decreased contractile function related to load-dependent parameters, including stroke volume index, ejection fraction, cardiac output index, stroke work index, and maximum derivative of change in systolic pressure over time. The load-independent parameters, preload recruitable stroke work and the slope (end-systolic volume elastance) of the end-systolic pressure-volume relationship, were significantly decreased in the senescent mice. Heart rate and arterial elastance were not different between the two groups; however, the ventricular-to-vascular coupling ratio (ratio of elastance of artery to end-systolic volume elastance) was increased by threefold in the senescent mice ( P < 0.001). Thus there were significant decreases in contractile function in the senescent mouse heart that appeared to be related to reduced mechanical efficiency but not related to arterial elastance.


2020 ◽  
Vol 41 (Supplement_2) ◽  
Author(s):  
P Barbier ◽  
G Liu ◽  
S Corona ◽  
M Scorsin ◽  
S Moriggia ◽  
...  

Abstract Background Regional longitudinal left ventricular (LV) dysfunction in patients with mitral regurgitation (MR) due to valve prolapse (MVP) with normal ejection fraction has been recently described, with data pointing at dysfunction of the LV base related to dilatation of the mitral annulus. Purpose To investigate degree and extent of regional LV dysfunction and its mechanisms in patients with MVP and severe acute (MRa, n=27) or chronic (MRc, n=41) MR and no coronary disease, undergoing surgical valve repair with 3 months follow-up (FU); 20 normal subjects were used as controls (N). Methods Speckle-tracking echocardiography was performed pre- (Bas), 1 week (1w) and 4 months (4mo) post-operatively to measure longitudinal global (GLPSS, %), regional (RPSS, %) and segmental (SPSS) peak systolic strain. Maximum and minimum mitral annulus (MA) diameters were measured with 3D echo at Bas. We also evaluated: LV end-diastolic volume index (EDVi, ml/m2); ejection fraction (EF, %); left atrial end-systolic volume index (LAVi, ml/m2); non-invasive pulmonary systolic pressure (PSP, mmHg). Results Risk factors (hypertension, diabetes, atrial fibrillation, smoke and previous stroke) were similar in MRc and MRa. At Bas EDVi was larger by definition in MRc (MRc: 102±21, MRa: 67±10 ml/m2, p&lt;0.001) as LAVi (101±46 vs 76±31 ml/m2, p=0.035). Both EF (65±8 vs 64±8 ml/m2) and GLPSS (−20±4 vs −21±5%) were normal, but RPSS was reduced, only at the base (−13±6 vs −13±6%, p= ns; N: −18±2, p&lt;0.03 vs MRc and MRa) in MRc and MRa, with reduced SPSS localized at anterior, lateral and posterior – but not septal – segments. At 1w, EF decreased in both MRc (47±14%, p&lt;0.001 vs Bas) and MRa (56±10%, p=0.014 vs Bas), together with GLPSS (MRc: −11±4%, p&lt;0.001 vs Bas; MRa; −13±4, p&lt;0.001 vs Bas) driven by a prevalent marked decrease in RPSS (MRc: −7±4%, p&lt;0.001 vs Bas; MRa; −8±5, p&lt;0.001 vs Bas) of the LV base. All patients were alive at 3 months with no MACEs, similar reduction of mean MR grade (MRc: 4±0 to 1.9±0.7, p&lt;0.001; MRa: 3.9±0.3 to 0.9±0.9, p&lt;0.001) and PSP (MRc: 50±23 to 29±5 mmHg, p&lt;0.001; MRa: 42±22 to 32±6 mmHg, p=0.039), normal EDVi (MRc: 70±27, MRa: 49±10 ml/m2), dilated LAVi (MRc: 101±46, MRa: 54±13 ml/m2), and reduced GLPSS (MRc: −12±5%, p&lt;0.001 vs Bas; MRa; −15±3, p=0.001 vs Bas) and base RPSS (MRc: −7±6%, p=0.004 vs Bas; MRa; −10±4, p= ns vs Bas). At multivariate analysis, regional dysfunction was not related to the prolapsing scallop, presence of flail, commissure involvement, dimension and geometry of the MA, EF or pulmonary pressures. Conclusions In patients with MVP and severe MR, there is a specific regional longitudinal dysfunction pattern prevalent at the LV base which may be related to the duration of MR but not to annular dilatation or morphology of the prolapsing leaflets. The dysfunction worsens greatly following acute reduction of preload after surgical repair and is still significant at 4mo FU. Funding Acknowledgement Type of funding source: None


2017 ◽  
Vol 1 (S1) ◽  
pp. 36-36
Author(s):  
Leo Buckley ◽  
Justin Canada ◽  
Salvatore Carbone ◽  
Cory Trankle ◽  
Michele Mattia Viscusi ◽  
...  

OBJECTIVES/SPECIFIC AIMS: Our goal was to compare the ventriculo-arterial coupling and left ventricular mechanical work of patients with systolic and diastolic heart failure (SHF and DHF). METHODS/STUDY POPULATION: Patients with New York Heart Association Functional Class II-III HF symptoms were included. SHF was defined as left ventricular (LV) ejection fraction<50% and DHF as >50%. Analysis of the fingertip arterial blood pressure tracing captured with a finger plethysmography cuff according to device-specific algorithms provided brachial artery blood pressure and stroke volume. LV end-systolic volume was measured separately via transthoracic echocardiography. Arterial elastance (Ea), a measure of pulsatile and nonpulsatile LV afterload, was calculated as LV end-systolic pressure (ESP)/end-diastolic volume. End-systolic elastance (Ees), a measure of load-independent LV contractility, was calculated as LV ESP/end-systolic volume. Ventriculo-arterial coupling (VAC) ratio was defined as Ea/Ees. Stroke work (SWI) was calculated as stroke volume index×LV end-systolic pressure×0.0136 and potential energy index (PEI) as 1/2×(LV end-systolic volume×LV end-systolic pressure×0.0136). Total work index (TWI) was the sum of SWI+PEI. RESULTS/ANTICIPATED RESULTS: Patients with SHF (n=52) and DHF (n=29) were evaluated. Median (IQR) age was 57 (51–64) years. There were 48 (58%) and 59 (71%) patients were male and African American, respectively. Cardiac index was 2.8 (2.2–3.2) L/minute and 3.0 (2.8–3.3) L/minute in SHF and DHF, respectively (p=0.12). Self-reported activity levels (Duke Activity Status Index, p=0.48) and heart failure symptoms (Minnesota Living with Heart Failure Questionnaire, p=0.55) were not different between SHF and DHF. Ea was significantly lower in DHF compared with SHF patients [1.3 (1.2–1.6) vs. 1.7 (1.4–2.0) mmHg; p<0.001] whereas Ees was higher in DHF vs. SHF [2.8 (2.1–3.1) vs. 0.9 (0.7-1.3) mmHg; p<0.001). VAC was 1.8 (1.3–2.8) in SHF Versus 0.5 (0.4–0.7) in DHF (p<0.001). Compared with SHF, DHF patients had higher SWI [71 (57–83) vs. 48 (39–68) gm×m; p<0.001) and lower PEI [19 (12–26) vs. 44 (36–57) gm×m; p<0.001]. TWI did not differ between SHF and DHF (p=0.14). Work efficiency was higher in DHF than SHF [0.80 (0.74–0.84) vs. 0.53 (0.46–0.64); p<0.001]. DISCUSSION/SIGNIFICANCE OF IMPACT: The results underscore the differences in pathophysiology between SHF and DHF patients with similar symptom burden and exercise capacity. These results highlight the difference in myocardial energy utilization between SHF and DHF.


Circulation ◽  
2007 ◽  
Vol 116 (suppl_16) ◽  
Author(s):  
Teruo Noguchi ◽  
Naoaki Yamada ◽  
Atushi Kawamura ◽  
Yoritaka Otsuka ◽  
Hiroshi Nonogi ◽  
...  

Backgroud: Left ventricular (LV) end-systolic volume index (ESVI) and ejection fraction (EF) are predictor of long-term mortality following an acute myocardial infarction(AMI). However, interpretation of these parameters within 1 week of AMI is difficult due to myocardial stunning. We sought to correlate size of microvascular obstruction (MO), EF, and ESVI determined by cardiac magnetic resonance (CMR) to major cardiovascular events (MACE) after primary coronary intervention for ST-elevation MI (STEMI). Methods: CMR was performed in 94 consecutive STEMI patients within 1 week following AMI. The following indexes were calculated: size of MO/LV mass, infarct mass, EF, and ESVI. Patients were divided into two groups according to the size of MO: large MO group (MO/LV ≥ 0.1) and small MO group (MO/LV < 0.1). A three-year clinical follow-up was recorded. Univariate and multivariate analyses were applied to identify predictors of MACE. Results: The mean LVEF and ESVI were 43 ± 13% and 49 ± 15 ml. The mean infarct mass was significantly greater in large MO group than that in small MO group (28 ± 15g vs. 19 ± 10g p<0.01). Survival without MACE was significantly lower in patients with large MO group in comparison to those with small MO group (log-rank p<0.001). Large MO (1.98 [95% CI 1.2–2.0], p=0.001), EF (0.91 [0.90 – 0.97], p=0.007), and ESVI (1.04 [1.01–1.06], p=0.01) were the only independent predictors of MACE. However, Large MO was a strongest predictor of MACE by multivariate analysis. Conclusions: EF, ESVI, and size of MO predict the future cardiac events. Size of MO measured by CMR, which is independent of stunning, was stronger predictors of MACE than either of the other two parameters.


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