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Mynard JP, Kowalski R, Harrington HA, Kondiboyina A, Smolich JJ, Cheung MMH. Superiority of a Representative MRI Flow Waveform over Doppler Ultrasound for Aortic Wave Reflection Assessment in Children and Adolescents With/Without a History of Heart Disease. Ann Biomed Eng 2023; 51:2772-2784. [PMID: 37561232 PMCID: PMC10632254 DOI: 10.1007/s10439-023-03339-2] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/01/2023] [Accepted: 07/29/2023] [Indexed: 08/11/2023]
Abstract
Wave separation analysis (WSA) reveals the impact of forward- and backward-running waves on the arterial pressure pulse, but the calculations require a flow waveform. This study investigated (1) the variability of the ascending aortic flow waveform in children and adolescents with/without a childhood heart disease history (CHD); (2) the accuracy of WSA obtained with a representative flow waveform (RepFlow), compared with the triangulation method and published ultrasound-derived adult representative flow; (3) the impact of limitations in Doppler ultrasound on WSA; and (4) generalizability of results to adults with a history of CHD. Phase contrast MRI was performed in youth without (n = 45, Group 1, 10-19 years) and with CHD (n = 79, Group 2, 7-18 years), and adults with CHD history (n = 29, Group 3, 19-59 years). Segmented aortic cross-sectional area was used as a surrogate for the central pressure waveform in WSA. A subject-specific virtual Doppler ultrasound was performed on MRI data by extracting velocities from a sample volume. Time/amplitude-normalized ascending aortic flow waveforms were highly consistent amongst all groups. WSA with RepFlow therefore yielded errors < 10% in all groups for reflected wave magnitude and return time. Absolute errors were typically 1.5-3 times greater with other methods, including subject-specific (best-case/virtual) Doppler ultrasound, for which velocity profile skewing introduced waveform errors. Our data suggest that RepFlow is the optimal approach for pressure-only WSA in children and adolescents with/without CHD, as well as adults with CHD history, and may even be more accurate than subject-specific Doppler ultrasound in the ascending aorta.
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Affiliation(s)
- Jonathan P Mynard
- Heart Research, Murdoch Children's Research Institute, 50 Flemington Road, Parkville, VIC, 3052, Australia.
- Department of Paediatrics, University of Melbourne, Parkville VIC, Australia.
- Department of Biomedical Engineering, University of Melbourne, Parkville VIC, Australia.
| | - Remi Kowalski
- Heart Research, Murdoch Children's Research Institute, 50 Flemington Road, Parkville, VIC, 3052, Australia
- Department of Paediatrics, University of Melbourne, Parkville VIC, Australia
- Department of Cardiology, Royal Children's Hospital, Parkville VIC, Australia
| | - Hilary A Harrington
- Heart Research, Murdoch Children's Research Institute, 50 Flemington Road, Parkville, VIC, 3052, Australia
| | - Avinash Kondiboyina
- Heart Research, Murdoch Children's Research Institute, 50 Flemington Road, Parkville, VIC, 3052, Australia
- Department of Paediatrics, University of Melbourne, Parkville VIC, Australia
| | - Joseph J Smolich
- Heart Research, Murdoch Children's Research Institute, 50 Flemington Road, Parkville, VIC, 3052, Australia
- Department of Paediatrics, University of Melbourne, Parkville VIC, Australia
| | - Michael M H Cheung
- Heart Research, Murdoch Children's Research Institute, 50 Flemington Road, Parkville, VIC, 3052, Australia
- Department of Paediatrics, University of Melbourne, Parkville VIC, Australia
- Department of Cardiology, Royal Children's Hospital, Parkville VIC, Australia
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Chen IY, Vedula V, Malik SB, Liang T, Chang AY, Chung KS, Sayed N, Tsao PS, Giacomini JC, Marsden AL, Wu JC. Preoperative Computed Tomography Angiography Reveals Leaflet-Specific Calcification and Excursion Patterns in Aortic Stenosis. Circ Cardiovasc Imaging 2021; 14:1122-1132. [PMID: 34915729 PMCID: PMC9206593 DOI: 10.1161/circimaging.121.012884] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
Abstract
BACKGROUND Computed tomography-based evaluation of aortic stenosis (AS) by calcium scoring does not consider interleaflet differences in leaflet characteristics. Here, we sought to examine the functional implications of these differences. METHODS We retrospectively reviewed the computed tomography angiograms of 200 male patients with degenerative calcific AS undergoing transcatheter aortic valve replacement and 20 male patients with normal aortic valves. We compared the computed tomography angiography (CTA)-derived aortic valve leaflet calcification load (AVLCCTA), appearance, and systolic leaflet excursion (LEsys) of individual leaflets. We performed computer simulations of normal valves to investigate how interleaflet differences in LEsys affect aortic valve area. We used linear regression to identify predictors of leaflet-specific calcification in patients with AS. RESULTS In patients with AS, the noncoronary cusp (NCC) carried the greatest AVLCCTA (365.9 [237.3-595.4] Agatston unit), compared to the left coronary cusp (LCC, 278.5 [169.2-478.8] Agatston unit) and the right coronary cusp (RCC, 240.6 [137.3-439.0] Agatston unit; both P<0.001). However, LCC conferred the least LEsys (42.8° [38.8°-49.0°]) compared to NCC (44.8° [41.1°-49.78°], P=0.001) and RCC (47.7° [42.0°-52.3°], P<0.001) and was more often characterized as predominantly thickened (23.5%) compared to NCC (12.5%) and RCC (16.5%). Computer simulations of normal valves revealed greater reductions in aortic valve area following closures of NCC (-32.2 [-38.4 to -25.8]%) and RCC (-35.7 [-40.2 to -32.9]%) than LCC (-24.5 [-28.5 to -18.3]%; both P<0.001). By linear regression, the AVLCCTA of NCC and RCC, but not LCC, predicted LEsys (both P<0.001) in patients with AS. Both ostial occlusion and ostial height of the right coronary artery predicted AVLCCTA, RCC (P=0.005 and P=0.001). CONCLUSIONS In male patients, the AVLCCTA of NCC and RCC contribute more to AS than that of LCC. LCC's propensity for noncalcific leaflet thickening and worse LEsys, however, should not be underestimated when using calcium scores to assess AS severity.
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Affiliation(s)
- Ian Y. Chen
- Stanford Cardiovascular Institute, Stanford University School of Medicine, Stanford, CA
- Medical Service, Cardiology Section, Veterans Affairs Palo Alto Health Care System, Palo Alto, CA
| | - Vijay Vedula
- Department of Mechanical Engineering, Columbia University, New York, NY
| | - Sachin B. Malik
- Department of Radiology, Stanford University School of Medicine, Stanford, CA
- Radiology Service, Veterans Affairs Palo Alto Health Care System, Palo Alto, CA
| | - Tie Liang
- Department of Radiology, Stanford University School of Medicine, Stanford, CA
| | - Andrew Y. Chang
- Department of Medicine, Division of Cardiovascular Medicine, Stanford University School of Medicine, Stanford, CA
| | - Kieran S. Chung
- Medical Service, Cardiology Section, Veterans Affairs Palo Alto Health Care System, Palo Alto, CA
| | - Nazish Sayed
- Stanford Cardiovascular Institute, Stanford University School of Medicine, Stanford, CA
| | - Philip S. Tsao
- Department of Medicine, Division of Cardiovascular Medicine, Stanford University School of Medicine, Stanford, CA
| | - John C. Giacomini
- Medical Service, Cardiology Section, Veterans Affairs Palo Alto Health Care System, Palo Alto, CA
- Department of Medicine, Division of Cardiovascular Medicine, Stanford University School of Medicine, Stanford, CA
| | | | - Joseph C. Wu
- Stanford Cardiovascular Institute, Stanford University School of Medicine, Stanford, CA
- Department of Radiology, Stanford University School of Medicine, Stanford, CA
- Department of Medicine, Division of Cardiovascular Medicine, Stanford University School of Medicine, Stanford, CA
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3
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Zhou X, Thavendiranathan P, Vannan MA. Quantification of Flow by 3D Color Flow Doppler:: From Pretty Pictures to Priceless Physiology. Can J Cardiol 2018; 34:703-704. [PMID: 29801735 DOI: 10.1016/j.cjca.2018.04.028] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/23/2018] [Accepted: 04/26/2018] [Indexed: 10/17/2022] Open
Affiliation(s)
- Xiao Zhou
- Chinese PLA General Hospital, Beijing, China
| | | | - Mani A Vannan
- Marcus Heart Valve Center, Piedmont Heart Institute, Atlanta, Georgia.
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Bech-Hanssen O, Svensson F, Polte CL, Johnsson ÅA, Gao SA, Lagerstrand KM. Characterization of complex flow patterns in the ascending aorta in patients with aortic regurgitation using conventional phase-contrast velocity MRI. Int J Cardiovasc Imaging 2017; 34:419-429. [PMID: 28871348 PMCID: PMC5847208 DOI: 10.1007/s10554-017-1239-3] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 06/30/2017] [Accepted: 08/31/2017] [Indexed: 01/15/2023]
Abstract
Ascending aorta (AA) flow displacement (FD) is a surrogate for increased wall shear stress. We prospectively studied the flow profile in the AA in patients with aortic regurgitation (AR), to identify predictors of FD and investigate whether magnetic resonance imaging (MRI) phase-contrast flow rate curves (PC-FRC) contain quantitative information related to FD. Forty patients with chronic moderate (n = 14) or severe (n = 26) AR (21 (53%) with bicuspid aortic valve) and 22 controls were investigated. FD was determined from phase-contrast velocity profiles and defined as the distance between the center of the lumen and the "center of velocity" of the peak systolic forward flow or the peak diastolic negative flow, normalized to the lumen radius. Forward and backward volume flow was determined separately for systole and diastole. Seventy percent had systolic backward flow and 45% had diastolic forward flow in large areas of the vessel. AA dimension was an independent predictor of systolic FD while AA dimension and regurgitant volume were independent predictors of diastolic FD. Valve phenotype was not an independent predictor of systolic or diastolic FD. The linear relationships between systolic backward flow and systolic FD and diastolic forward flow and diastolic FD were strong (R = 0.77 and R = 0.76 respectively). Systolic backward flow and diastolic forward flow identified marked systolic and diastolic FD (≥0.35) with a positive likelihood ratio of 6.0 and 10.8, respectively. In conclusion, conventional PC-FRC data can detect and quantify FD in patients with AR suggesting the curves as a research and screening tool in larger patient populations.
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Affiliation(s)
- Odd Bech-Hanssen
- Departments of Clinical Physiology, The Sahlgrenska Academy at the University of Gothenburg, Gothenburg, Sweden. .,Institute of Medicine at the Sahlgrenska Academy, Sahlgrenska University Hospital, Gothenburg, Sweden.
| | - Frida Svensson
- Departments of Diagnostic Radiation Physics, The Sahlgrenska Academy at the University of Gothenburg, Gothenburg, Sweden
| | - Christian L Polte
- Departments of Cardiology, The Sahlgrenska Academy at the University of Gothenburg, Gothenburg, Sweden.,Institute of Medicine at the Sahlgrenska Academy, Sahlgrenska University Hospital, Gothenburg, Sweden
| | - Åse A Johnsson
- Departments of Radiology, The Sahlgrenska Academy at the University of Gothenburg, Gothenburg, Sweden.,Departments of Clinical Sciences, The Sahlgrenska Academy at the University of Gothenburg, Gothenburg, Sweden
| | - Sinsia A Gao
- Departments of Clinical Physiology, The Sahlgrenska Academy at the University of Gothenburg, Gothenburg, Sweden.,Institute of Medicine at the Sahlgrenska Academy, Sahlgrenska University Hospital, Gothenburg, Sweden
| | - Kerstin M Lagerstrand
- Departments of Diagnostic Radiation Physics, The Sahlgrenska Academy at the University of Gothenburg, Gothenburg, Sweden
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Ramaswamy S, Lordeus M, Mankame OV, Valdes-Cruz L, Bibevski S, Bell SM, Baez I, Scholl F. Hydrodynamic Assessment of Aortic Valves Prepared from Porcine Small Intestinal Submucosa. Cardiovasc Eng Technol 2016; 8:30-40. [PMID: 27995570 DOI: 10.1007/s13239-016-0290-x] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 09/01/2016] [Accepted: 12/10/2016] [Indexed: 10/20/2022]
Abstract
Infants and children born with severe cardiac valve lesions have no effective long term treatment options since currently available tissue or mechanical prosthetic valves have sizing limitations and no avenue to accommodate the growth of the pediatric patient. Tissue engineered heart valves (TEHVs) which could provide for growth, self-repair, infection resistance, and long-term replacement could be an ideal solution. Porcine small intestinal submucosa (PSIS) has recently emerged as a potentially attractive bioscaffold for TEHVs. PSIS may possess the ability to recruit endogenous cardiovascular cells, leading to phenotypically-matched replacement tissue when the scaffold has completely degraded. Our group has successfully implanted custom-made PSIS valves in 4 infants with critical valve defects in whom standard bioprosthetic or mechanical valves were not an option. Short term clinical follow-up has been promising. However, no hydrodynamic data has been reported to date on these valves. The purpose of this study was to assess the functional effectiveness of tri-leaflet PSIS bioscaffolds in the aortic position compared to standard tri-leaflet porcine bioprosthetic valves. Hydrodynamic evaluation of acute PSIS function was conducted using a left heart simulator in our laboratory. Our results demonstrated similar flow and pressure profiles (p > 0.05) between the PSIS valves and the control valves. However, forward flow energy losses were found to be significantly greater (p < 0.05) in the PSIS valves compared to the controls possibly as a result of stiffer material properties of PSIS relative to glutaraldehyde-fixed porcine valve tissue. Our findings suggest that optimization of valve dimensions and shape may be important in accelerating de novo valve tissue growth and avoidance of long-term complications associated with higher energy losses (e.g. left ventricular hypertrophy). Furthermore, long term animal and clinical studies will be needed in order to conclusively address somatic growth potential of PSIS valves.
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Affiliation(s)
- Sharan Ramaswamy
- Department of Biomedical Engineering, College of Engineering and Computing, Florida International University, 10555 W. Flagler Street, EC 2612, Miami, FL, 33174, USA.
| | - Makensley Lordeus
- Department of Biomedical Engineering, College of Engineering and Computing, Florida International University, 10555 W. Flagler Street, EC 2612, Miami, FL, 33174, USA
| | - Omkar V Mankame
- Department of Biomedical Engineering, College of Engineering and Computing, Florida International University, 10555 W. Flagler Street, EC 2612, Miami, FL, 33174, USA
| | | | - Steven Bibevski
- The Heart Institute, Joe DiMaggio Children's Hospital, Hollywood, FL, USA
| | - Sarah M Bell
- The Heart Institute, Joe DiMaggio Children's Hospital, Hollywood, FL, USA
| | - Ivan Baez
- The Heart Institute, Joe DiMaggio Children's Hospital, Hollywood, FL, USA
| | - Frank Scholl
- The Heart Institute, Joe DiMaggio Children's Hospital, Hollywood, FL, USA
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Matre K, Ersland L, Larsen TH, Andersen E. In Vitro Agreement between Magnetic Resonance Imaging and Intraluminal Doppler Ultrasound for High Flow Velocity Measurements. SCAND CARDIOVASC J 2009. [DOI: 10.1080/cdv.36.3.180.186] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 10/20/2022]
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Fogel MA, Weinberg PM, Haselgrove J. The Impact of Aortic Arch Geometry on Flow Dynamics Using a Simplified Approach with Magnetic Resonance Velocity Mapping. CONGENIT HEART DIS 2006; 1:300-8. [DOI: 10.1111/j.1747-0803.2006.00051.x] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/26/2022]
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8
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YOKOSAWA S, NAKAMURA M, WADA S, ISODA H, TAKEDA H, YAMAGUCHI T. Quantitative Measurements on the Human Ascending Aortic Flow Using 2D Cine Phase-Contrast Magnetic Resonance Imaging. ACTA ACUST UNITED AC 2005. [DOI: 10.1299/jsmec.48.459] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022]
Affiliation(s)
- Suguru YOKOSAWA
- Department of Bioengineering and Robotics, Graduate School of Engineering, Tohoku University
| | - Masanori NAKAMURA
- Department of Bioengineering and Robotics, Graduate School of Engineering, Tohoku University
| | - Shigeo WADA
- Department of Bioengineering and Robotics, Graduate School of Engineering, Tohoku University
| | - Haruo ISODA
- Department of Radiology, Hamamatsu University School of Medicine
| | - Hiroyasu TAKEDA
- Department of Radiology, Hamamatsu University School of Medicine
| | - Takami YAMAGUCHI
- Department of Bioengineering and Robotics, Graduate School of Engineering, Tohoku University
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9
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Tsujino H, Jones M, Qin JX, Sitges M, Cardon LA, Morehead AL, Zetts AD, Bauer F, Kim YJ, Hang XY, Greenberg N, Thomas JD, Shiota T. Combination of pulsed-wave Doppler and real-time three-dimensional color Doppler echocardiography for quantifying the stroke volume in the left ventricular outflow tract. ULTRASOUND IN MEDICINE & BIOLOGY 2004; 30:1441-1446. [PMID: 15588954 DOI: 10.1016/j.ultrasmedbio.2004.08.027] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/03/2003] [Revised: 08/25/2004] [Accepted: 08/31/2004] [Indexed: 05/24/2023]
Abstract
Real-time three-dimensional (3-D) color Doppler echocardiography (RT3D) is capable of quantifying flow. However, low temporal resolution limits its application to stroke volume (SV) measurements. The aim of the present study was, therefore, to develop a reliable method to quantify SV. In animal experiments, cross-sectional images of the LV outflow tract were selected from the RT3D data to calculate peak flow rates (Q(p3D)). Conventional pulsed-wave (PW) Doppler was performed to measure the velocity-time integral (VTI) and the peak velocity (V(p)). By assuming that the flow is proportional to the velocity temporal waveform, SV was calculated as alpha x Q(p3D) x VTI/V(p), where alpha is a temporal correction factor. There was an excellent correlation between the reference flow meter and RT3D SV (mean difference = -1. 3 mL, y = 1. 05 x -2. 5, r = 0. 94, p < 0. 01). The new method allowed accurate SV estimations without any geometric assumptions of the spatial velocity distributions.
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Affiliation(s)
- Hiroyuki Tsujino
- Cardiovascular Imaging Center, The Cleveland Clinic Foundation, Cleveland, OH 44195, USA
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10
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Garcia D, Pibarot P, Landry C, Allard A, Chayer B, Dumesnil JG, Durand LG. Estimation of aortic valve effective orifice area by Doppler echocardiography: effects of valve inflow shape and flow rate. J Am Soc Echocardiogr 2004; 17:756-65. [PMID: 15220901 DOI: 10.1016/j.echo.2004.03.030] [Citation(s) in RCA: 50] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 10/25/2022]
Abstract
BACKGROUND The effective orifice area (EOA) is the standard parameter for the clinical assessment of aortic stenosis severity. It has been reported that EOA measured by Doppler echocardiography does not necessarily provide an accurate estimate of the cross-sectional area of the flow jet at the vena contracta, especially at low flow rates. The objective of this study was to test the validity of the Doppler-derived EOA. METHODS Triangular and circular orifice plates, funnels, and bioprosthetic valves were inserted into an in vitro aortic flow model and were studied under different physiologic flow rates corresponding to cardiac outputs varying from 1.5 to 7 L/min. For each experiment, the EOA was measured by Doppler and compared with the catheter-derived EOA and with the EOA derived from a theoretic formula. In bioprostheses, the geometric orifice area (GOA) was estimated from images acquired by high-speed video recording. RESULTS There was no significant difference between the EOA derived from the 3 methods with the rigid orifices (Doppler vs catheter: y = 0.97x +0.18 mm(2), r(2) = 0.98; Doppler vs theory: y = 1.00x -3.60 mm(2), r(2) = 0.99). Doppler EOA was not significantly influenced by the flow rate in rigid orifices. As predicted by theory, the average contraction coefficient (EOA/GOA) was around 0.6 in the orifice plates and around 1.0 in the funnels. In the bioprosthetic valves, both EOA and GOA increased with increasing flow rate whereas contraction coefficient was almost constant with an average value of 0.99. There was also a very good concordance between EOA and GOA (y = 0.94x +0.05 mm(2), r(2) = 0.88). CONCLUSIONS In rigid aortic stenosis, the Doppler EOA is much less flow dependent than generally assumed. Indeed, it depends mainly on the GOA and the inflow shape (flat vs funnel-shaped) of the stenosis. The flow dependence of Doppler EOA observed in clinical studies is likely a result of a variation of the valve GOA or of the valve inflow shape and not an inherent flow dependence of the EOA derived by the continuity equation.
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Affiliation(s)
- Damien Garcia
- Institut de Recherches Cliniques de Montréal, Canada
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11
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Pennati G, Bellotti M, De Gasperi C, Rognoni G. Spatial velocity profile changes along the cord in normal human fetuses: can these affect Doppler measurements of venous umbilical blood flow? ULTRASOUND IN OBSTETRICS & GYNECOLOGY : THE OFFICIAL JOURNAL OF THE INTERNATIONAL SOCIETY OF ULTRASOUND IN OBSTETRICS AND GYNECOLOGY 2004; 23:131-137. [PMID: 14770391 DOI: 10.1002/uog.938] [Citation(s) in RCA: 15] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/24/2023]
Abstract
OBJECTIVE Several studies have assumed a parabolic velocity profile through the umbilical vein (UV) to derive the mean spatial velocity that is indispensable for flow rate calculations. However, the structure and arrangement of the umbilical cord suggest that velocity profiles may vary. The aim of this study was to evaluate UV spatial flow velocity profiles at different sites along the umbilical cord. METHODS Ten singleton pregnancies with a gestational age between 26 and 34 weeks were included in the study. Ultrasound equipment with an inbuilt function for analysis of the spatial velocity profile along a line located in a fixed plane was used to obtain UV velocity profiles. Velocity profiles were obtained at the placental insertion and in a free intra-amniotic loop of the cord. Two-dimensional (2D) velocity distribution coefficients were evaluated as ratios between mean and maximum velocities along the investigated lines. RESULTS 2D velocity distribution coefficients at the placental insertion (0.85 +/- 0.03) were significantly higher (P < 0.00001) than those obtained from a free loop of cord (0.76 +/- 0.03). Values indicated that velocity profiles are approximately flat at the placental insertion and become more parabolic moving downstream. Moreover, profiles become skewed in association with cord curvature and show peculiar biphasic shapes immediately downstream from the placenta. CONCLUSIONS Flow velocity profiles in the UV are not perfectly parabolic and modify along the cord. These characteristics may affect the evaluation of UV blood flow rate.
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Affiliation(s)
- G Pennati
- Laboratory of Mechanics of Biological Structures, Department of Bioengineering, Politecnico di Milano University of Milan, Milan, Italy.
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12
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Haugen BO, Berg S, Brecke KM, Torp H, Slørdahl SA, Skaerpe T, Samstad SO. Blood flow velocity profiles in the aortic annulus: a 3-dimensional freehand color flow Doppler imaging study. J Am Soc Echocardiogr 2002; 15:328-33. [PMID: 11944010 DOI: 10.1067/mje.2002.117292] [Citation(s) in RCA: 31] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
BACKGROUND The use of a single sample volume in Doppler measurements of the velocity time integral (VTI) in the aortic annulus may introduce errors in calculations of stroke volumes, shunts, regurgitant fractions, and aortic valve area. To study the blood flow velocity distribution and assess this potential error, we used a dynamic 3-dimensional color flow Doppler imaging method. METHODS AND RESULTS Seventeen healthy volunteers were studied. The ultrasound data were captured from 10 to 20 heartbeats at a high frame rate (mean 57 frames per second) while freely tilting the transducer in the apical position. A magnetic position-sensor system recorded the spatial position and orientation of the probe. The raw digital ultrasound data were analyzed off-line with no loss of temporal resolution. Blood flow velocities were integrated across a spherical surface that tracked the aortic annulus during systole. The ratios of the systolic maximum to the systolic mean VTI ranged from 1.2 to 1.5 (mean 1.4). At the time of systolic peak flow, the ratios of the maximum to the mean velocity ranged from 1.1 to 2.0 (mean 1.5). The location of the maximum velocities and VTI showed individual variation. CONCLUSION The blood flow velocity profile was nonuniform. By using a single sample volume in Doppler measurements of the VTI in the aortic annulus, errors ranging from 20% to 50% may be introduced in calculations of stroke volumes.
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Affiliation(s)
- Bjørn Olav Haugen
- Departments of Cardiology and Lung Medicine, Norwegian University of Science and Technology, University Hospital of Trondheim, Olav Kyrres gt 17, N-7006 Trondheim, Norway.
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13
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Antonini-Canterin F, Pavan D, Burelli C, Cassin M, Cervesato E, Nicolosi GL. Validation of the ejection fraction-velocity ratio: a new simplified "function-corrected" index for assessing aortic stenosis severity. Am J Cardiol 2000; 86:427-33. [PMID: 10946037 DOI: 10.1016/s0002-9149(00)00959-0] [Citation(s) in RCA: 13] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
A new echocardiographic method for the evaluation of aortic stenosis (AS) severity has recently been introduced: the fractional shortening-velocity ratio (FSVR = fractional shortening/4 Vmax(2)). An important advantage of the method is the possibility of avoiding the difficulties related to the measurement of left ventricular outflow tract in calcific AS for assessing the continuity equation. FSVR, however, also shows some significant limitations especially in patients with regional wall motion abnormalities and conduction defects. To overcome this problem, we developed a new index: the ejection fraction-velocity ratio (EFVR = ejection fraction/4 Vmax(2)), where percent ejection fraction and Vmax have been obtained with an apical echocardiographic approach. In 343 consecutive patients with AS, aortic valve area was measured by cardiac catheterization (Gorlin), whereas FSVR and EFVR were calculated by echo-Doppler examination performed within 24 hours. Mean valve area was 0.70 +/- 0.30 cm(2), mean EFVR was 0.78 +/- 0.41, and mean FSVR was 0.45 +/- 0.26. The linear correlation area-EFVR was highly significant (r = 0.88). Correlation valve area-FSVR was also significant (r = 0.82). EFVR allowed identification of patients with severe AS (area </=0.8 cm(2)) with good sensitivity (88%) and specificity (85%), whereas FSVR demonstrated sensitivity of 88% and specificity of 73%. Thus, the EFVR, a very simple and not time-consuming index, is strongly related to aortic valve area in patients with AS. It allows identification of patients with severe AS with good sensitivity and specificity (better than FSVR). The EFVR, taking into consideration both ejection fraction and transvalvular pressure gradient, may be very useful in the evaluation of patients with AS and left ventricular dysfunction.
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Affiliation(s)
- F Antonini-Canterin
- Divisione di Cardiologia, ARC, Azienda Ospedaliera Santa Maria degli Angeli, Pordenone, Italy
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Lladó (coordinador) GP, Costa FC, Beiras AC, Domínguez JF, Romo AI, Jiménez Borreguero LJ, Gálvez y Rafaela Soler Fernández CP. Guías de práctica clínica de la Sociedad Española de Cardiología en resonancia magnética. Rev Esp Cardiol 2000. [DOI: 10.1016/s0300-8932(00)75125-6] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/27/2022]
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