Abstract 12586: Assessing Valvuloarterial Impedance in Aortic Stenosis: A Comparison of Echocardiographic- and Cardiac Magnetic Resonance-derived Methods

Circulation ◽  
2020 ◽  
Vol 142 (Suppl_3) ◽  
Author(s):  
Sara L Hungerford ◽  
Audrey Adji ◽  
Nicole K Bart ◽  
Linda Lin ◽  
Andrew Jabbour ◽  
...  
Keyword(s):  
Cardiac Magnetic Resonance ◽  
Magnetic Resonance ◽  
Aortic Stenosis ◽  
Flow Velocity ◽  
Cuff Pressure ◽  
Ventricular Outflow Tract ◽  
Left Ventricular ◽  
Applanation Tonometry ◽  
Aortic Flow ◽  
Entire Cross Section

Introduction: Valvuloarterial impedance (Z VA ) represents the valvular and arterial factors that oppose Left Ventricular (LV) ejection and is recognised as an important index to assess global LV load in patients with Aortic Stenosis (AS). Z VA is traditionally determined by Transthoracic Echocardiogram (TTE) and brachial cuff pressure. Hypothesis: Our study sought to compare Z VA-TTE with Z VA calculated using a simultaneous Cardiac Magnetic Resonance (CMR) and Applanation Tonometry (AT) (Z VA-CMR ) technique to determine whether TTE measurement of aortic flow velocity resulted in an underestimation of Z VA. Methods: Twenty AS patients underwent a protocol of CMR/AT followed by TTE. Z VA-CMR was determined as the relationship of derived aortic pressure (radial) to CMR aortic flow velocity in the frequency domain. Z VA-TTE was determined from digitised flow velocity within the left ventricular outflow tract (LVOT) on pulsed-wave Doppler and derived central pressure waveforms. Systemic vascular resistance (SVR) was calculated from mean pressure and flow. Values from both methods were compared. Results: Our study found that Z VA-TTE values (mean±SD, 638±381 dyne.s.cm -3 ) were consistently lower (p=0.07) than Z VA-CMR values (946±318 dyne.s.cm -3 ), and attribute this to an overestimation of LVOT flow velocity on TTE. SVR calculated by CMR/AT (2215±616 dyne.s.cm -5 ) was almost four times higher than TTE (618±245 dyne.s.cm -5 ) (p<0.001). This is due to more robust axi-symmetrical sampling of aortic flow across the entire cross-section of the ascending aorta (well above the stenotic jet) during CMR, than using operator-dependent TTE. Conclusions: Whilst Z VA -TTE is commonly performed in patients with AS to assess global LV load, newer methods to assess Z VA using simultaneous CMR/AT likely represent a more accurate non-invasive assessment.

scholarly journals Real-time cardiac magnetic resonance tissue characterisation for fibrosis assessment in aortic stenosis

2020 ◽  
Vol 41 (Supplement_2) ◽  
Author(s):  
S.J Backhaus ◽  
T Lange ◽  
B.E Beuthner ◽  
R Topci ◽  
X Wang ◽  
...  
Keyword(s):  
Cardiac Magnetic Resonance ◽  
Magnetic Resonance ◽  
Aortic Stenosis ◽  
Real Time ◽  
Volume Fraction ◽  
Left Ventricular ◽  
Funding Source ◽  
Single Shot ◽  
Post Contrast ◽  
Native T1

Abstract Background Myocardial fibrosis is a major determinant of outcome in aortic stenosis (AS). Novel fast real-time (RT) cardiac magnetic resonance (CMR) mapping techniques allow comprehensive quantification of fibrosis but have not yet been adequately validated against standard techniques and histology. Methods Patients with severe AS underwent CMR before (n=110) and left ventricular (LV) endomyocardial biopsy (n=46) at transcatheter aortic valve replacement (TAVR). Midventricular short axis native, post-contrast T1 and extracellular volume fraction (ECV) maps were generated using commercially available 5(3)3 MOLLI and RT single-shot inversion recovery fast low-angle shot (FLASH) with radial undersampling. ECV and LV mass were used to calculate LV matrix volumes. Variability and agreements were assessed between RT, MOLLI and histology using intraclass correlation coefficients, coefficients of variation and Bland Altman analyses. Results RT and MOLLI derived ECV were similar for myocardium (26.2 vs. 26.5, p=0.073) and inter-ventricular septum (26.2 vs. 26.5, p=0.216). MOLLI native T1 time was in median 20 ms longer compared to RT (p&lt;0.001). Agreement between RT and MOLLI was best for ECV (ICC &gt;0.91), excellent for post-contrast T1 times (ICC &gt;0.81) and good for native T1 times (ICC &gt;0.62). Diffuse collagen volume fraction by biopsies was in median 7.8%. ECV (RT r=0.345, p=0.039; MOLLI r=0.40, p=0.010) and LV matrix volumes (RT r=0.45, p=0.005; MOLLI r=0.43, p=0.007) were the only parameters associated with histology. Conclusions RT mapping offers precise T1 and ECV assessments with similar agreement with histology as compared to conventional MOLLI techniques. Single-shot real time techniques may be advantageous in sicker patients prone to dyspnoea or arrhythmia. Funding Acknowledgement Type of funding source: Foundation. Main funding source(s): German Research Foundation

Abnormal myocardial blood flow in children with mild/moderate aortic stenosis

2015 ◽  
Vol 25 (7) ◽  
pp. 1358-1366 ◽  
Author(s):  
Erin Madriago ◽  
Ronald Wells ◽  
David J. Sahn ◽  
Brian S. Diggs ◽  
Stephen M. Langley ◽  
...  
Keyword(s):  
Blood Flow ◽  
Cardiac Magnetic Resonance ◽  
Magnetic Resonance ◽  
Aortic Stenosis ◽  
Myocardial Blood Flow ◽  
Left Ventricular ◽  
Infants And Children ◽  
Adenosine Infusion ◽  
Absolute Increase ◽  
Asymptomatic Children

AbstractObjectiveTo quantify myocardial blood flow in infants and children with mild or moderate aortic stenosis using adenosine-infusion cardiac magnetic resonance.BackgroundIt is unclear whether asymptomatic children with mild/moderate aortic stenosis have myocardial abnormalities. In addition, cardiac magnetic resonance-determined normative myocardial blood flow data in children have not been reported.MethodsWe studied 31 infants and children with either haemodynamically normal hearts (n=20, controls) or mild/moderate aortic stenosis (n=11). The left ventricular myocardium was divided into six segments, and the change in average segmental signal intensity during contrast transit was used to quantify absolute flow (ml/g/minute) at rest and during adenosine infusion by deconvolution of the tissue curves with the arterial input of contrast.ResultsIn all the cases, adenosine was well tolerated without complications. The mean pressure gradient between the left ventricle and the ascending aorta was higher in the aortic stenosis group compared with controls (24 versus 3 mmHg, p<0.001). Left ventricular wall mass was slightly higher in the aortic stenosis group compared with controls (65 versus 50 g/m2, p<0.05). After adenosine treatment, both the absolute increase in myocardial blood flow (p<0.0001) and the hyperaemic flow significantly decreased (p<0.001) in children with mild/moderate aortic stenosis compared with controls.ConclusionAbnormal myocardial blood flow in children with mild/moderate aortic stenosis may be an important therapeutic target.

scholarly journals Usefulness of Cardiac Magnetic Resonance Imaging in Aortic Stenosis

2020 ◽  
Vol 13 (5) ◽  
Author(s):  
Yohann Bohbot ◽  
Cédric Renard ◽  
Alain Manrique ◽  
Franck Levy ◽  
Sylvestre Maréchaux ◽  
...  
Keyword(s):  
Magnetic Resonance Imaging ◽  
Cardiac Magnetic Resonance ◽  
Magnetic Resonance ◽  
Aortic Stenosis ◽  
Left Ventricular ◽  
Flow Quantification ◽  
Low Flow ◽  
Left Ventricular Volumes ◽  
Resonance Imaging ◽  
And Function

The objective of this review is to provide an overview of the role of cardiac magnetic resonance (CMR) in aortic stenosis (AS). Although CMR is undeniably the gold standard for assessing left ventricular volume, mass, and function, the assessment of the left ventricular repercussions of AS by CMR is not routinely performed in clinical practice, and its role in evaluating and quantifying AS is not yet well established. CMR is an imaging modality integrating myocardial function and disease, which could be particularly useful in a pathology like AS that should be considered as a global myocardial disease rather than an isolated valve disease. In this review, we discuss the emerging potential of CMR for the diagnosis and prognosis of AS. We detail its utility for studying all aspects of AS, including valve anatomy, flow quantification, left ventricular volumes, mass, remodeling, and function, tissue mapping, and 4-dimensional flow magnetic resonance imaging. We also discuss different clinical situations where CMR could be useful in AS, for example, in low-flow low-gradient AS to confirm the low-flow state and to understand the reason for the left ventricular dysfunction or when there is a suspicion of associated cardiac amyloidosis.

scholarly journals Application of the Proximal Isovelocity Surface Area Method for Estimation of the Effective Orifice Area in Aortic Stenosis

2021 ◽  
Author(s):  
Masahiro Nakabachi ◽  
Hiroyuki Iwano ◽  
Michito Murayama ◽  
Hisao Nishino ◽  
Shinobu Yokoyama ◽  
...  
Keyword(s):  
Aortic Stenosis ◽  
Flow Velocity ◽  
Surface Area ◽  
Continuity Equation ◽  
Ventricular Outflow Tract ◽  
Left Ventricular ◽  
Effective Orifice Area ◽  
Orifice Area ◽  
Proximal Isovelocity Surface Area ◽  
The Difference

Abstract Purpose: Because existence of high flow velocity at the left ventricular outflow tract (LVOT) potentially causes an overestimation of effective orifice area (EOA) by continuity equation in aortic stenosis (AS), we tested the proximal isovelocity surface area (PISA) method as an alternative tool for AS.Methods: EOA was calculated using the continuity equation (EOACont) and PISA method (EOAPISA), respectively, in 114 patients with at least moderate AS. The geometric orifice area (GOA) was also measured in 51 patients who also underwent three-dimensional transesophageal echocardiography (TEE). Patients were divided into two groups according to the median LVOT flow velocity.Results: Feasibility of EOAPISA was 95% in the 114 patients. While there was a strong correlation between EOACont and EOAPISA, EOACont was greater than EOAPISA especially in patients with high LVOT velocity. In TOE cohort, both EOACont and EOAPISA similarly correlated with GOA. However, a fixed bias, which is supposed to exist in AS, was observed only between EOAPISA and GOA with smaller EOAPISA than GOA. The difference between EOACont and GOA was significantly greater with a larger EOACont relative to GOA in patients with high LVOT velocity than in those without (0.16±0.25 vs -0.07±0.10 cm2, P<0.001). In contrast, the difference between EOAPISA and GOA was consistent in both groups (-0.07±0.12 vs -0.07±0.15 cm2, P = 0.936). Conclusion: The PISA method was applied to estimate EOA of AS. EOAPISA could be an alternative parameter for AS severity grading in patients with high LVOT velocity in whom EOACont would overestimate the orifice area.

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