Doppler Color Flow Mapping of the Proximal Isovelocity Surface Area: A New Method for Measuring Volume Flow Rate Across a Narrowed Orifice

Utsunomiya, Toshinori; Ogawa, Toshio; Tang, Hoang A.; Doshi, Rajen; Patel, Dhaval; Quan, Maureen; Henry, Walter L.; Gardin, Julius M.

doi:10.1016/s0894-7317(14)80444-6

Cited by 70 publications

(17 citation statements)

References 13 publications

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“…Alternatively, the vena contracta method29 or Doppler echocardiography of the descending aorta,30 31 in addition to colour Doppler echocardiography, can be used. During our study protocol, the proximal isovelocity surface area method (PISA) for the assessment of the aortic regurgitation32 33 was not applicable in most patients because of the relatively small proximal chamber size (aortic root) and because of frequent artefacts close to valve calcifications.…”

Section: Discussionmentioning

confidence: 99%

Influence of left ventricular relaxation on the pressure half time of aortic regurgitation

Marchi

Windecker

Aeschbacher

et al. 1999

Heart

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Background-The severity of aortic regurgitation can be estimated using pressure half time (PHT) of the aortic regurgitation flow velocity, but the correlation between regurgitant fraction and PHT is weak. Aim-To test the hypothesis that the association between PHT and regurgitant fraction is substantially influenced by left ventricular relaxation. Methods-In 63 patients with aortic regurgitation, subdivided into a group without (n = 22) and a group with (n = 41) left ventricular hypertrophy, regurgitant fraction was calculated using the diVerence between right and left ventricular cardiac outputs. Left ventricular relaxation was assessed using the early to late diastolic Doppler tissue velocity ratio of the mitral annulus (E/ADTI), the E/A ratio of mitral inflow (E/AM), and the E deceleration time (E-DT). Left ventricular hypertrophy was assessed using the M mode derived left ventricular mass index. Results-The overall correlation between regurgitant fraction and PHT was weak (r = 0.36, p < 0.005). In patients without left ventricular hypertrophy, there was a significant correlation between regurgitant fraction and PHT (r = 0.62, p < 0.005), but not in patients with left ventricular hypertrophy. In patients with a left ventricular relaxation abnormality (defined as E/ADTI< 1, E/AM< age corrected lower limit, E-DT > 220 ms), no associations between regurgitant fraction and PHT were found, whereas in patients without left ventricular relaxation abnormalities, the regurgitant fraction to PHT relations were significant (normal E/AM: r = 0.57, p = 0.02; E-DT< 220 ms: r = 0.50, p < 0.001; E/ADTI < 1: r = 0.57, p = 0.02). Conclusions-Only normal left ventricular relaxation allows a significant decay of PHT with increasing aortic regurgitation severity. In abnormal relaxation, which is usually present in left ventricular hypertrophy, wide variation in prolonged backward left ventricular filling may cause dissociation between the regurgitant fraction and PHT. Thus the PHT method should only be used in the absence of left ventricular relaxation abnormalities. (Heart 1999;82:607-613) Keywords: aortic regurgitation; left ventricular relaxation; pressure half time Although severe aortic regurgitation should be corrected when more than mild symptoms develop, there is compelling evidence that patients with this condition should undergo valve replacement before the onset of permanent left ventricular damage, even in the absence of symptoms.1-3 The "55 rule" has been useful in gauging the timing of surgery in severe aortic regurgitation-that is, it ought to be performed before the ejection fraction falls below 55% or the end systolic left ventricular dimension exceeds 55 mm.1-3 The rule requires a correct classification of the severity of aortic regurgitation, a task which is now mainly performed using Doppler echocardiography. A standard method for the measurement of aortic regurgitation is the determination of the pulmonary to systemic cardiac output ratio. 5However, this is very time consuming and often not applica...

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Section: Discussionmentioning

confidence: 99%

Influence of left ventricular relaxation on the pressure half time of aortic regurgitation

Marchi

Windecker

Aeschbacher

et al. 1999

Heart

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“…Streamlines and particle tracking have been used in computer simulation and laboratory experiments to identify these regions. Streamlines have been used to better visualize and quantify pre-and post-stenotic pulsed Doppler measurements in laminar and turbulent flow ( 8 ) , (13)(14)(15). Using Indium-111 labeled transferrin platelets, arterial thrombus formation was correlated with flow patterns described with nonparallel streamlines (16,17).…”

Section: Discussionmentioning

confidence: 99%

Algorithms for improving calculated streamlines in 3‐D phase contrast angiography

Buonocore

1994

Magnetic Resonance in Med

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Streamline display is a unique alternative to cross-sectional slice or projection display, because streamlines more clearly show the patterns of blood flow within the vessel. Flow patterns associated with atherosclerosis, such as streamline separation and recirculation, can be quickly identified with this display. Streamlines can be calculated using velocity data obtained from 3-D phase contrast angiographic pulse sequences. However, these streamlines often pass through the wall of vessel or show intraluminal sources and sinks of blood. The author has developed iterative least squares algorithms to improve the realism of streamlines. The velocity data is modified so that the resulting streamlines do not pass through the vessel wall and there are no intraluminal sources or sinks. He has applied the algorithms to velocity data obtained from a flow phantom and the carotid arteries of normal volunteers. Streamlines derived from the processed velocity fields are more realistic and provide more precise flow quantitation.

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“…20 Their results imply that the hemielliptic method is more accurate than the hemispheric method, and that the hemielliptic method can be applied not only to a constant flow system but also to a pulsatile flow system. 6,[20][21][22] In a pulsatile flow system simulating flow conditions in valvular stenosis, Denning et al 23 also evaluated whether flow rate in the orifice area could be determined accurately based on color Doppler flow mapping using a continuity equation. 18,19 They concluded that the prestenotic flow rate and functional orifice area could be evaluated reliably in a pulsatile flow system.…”

Section: Study Limitationsmentioning

confidence: 98%

“…During their experimental in vitro studies, Bargiggia et al 1 used a round orifice and assumed that the flow convergence region was hemispheric and calculated the flow rate as 2 πr 2 times the aliasing velocity by applying a continuity equation. 18,19 Utsunomiya et al named the surface of the convergence flow 'proximal isovelocity surface area' (PISA), 4,8,20 assuming that the PISA was hemielliptic (hemielliptic method). They concluded that the flow rate calculated using the hemielliptic method was more accurate than that calculated using the hemispheric method, especially when the orifice shape was rectangular.…”

Section: Previous Studiesmentioning

confidence: 99%

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Hemielliptic Proximal Isovelocity Surface Area Method Modified for Clinical Application. More Accurate Quantification of Mitral Regurgitation in Doppler Echocardiography.

et al. 2001

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Doppler Color Flow Mapping of the Proximal Isovelocity Surface Area: A New Method for Measuring Volume Flow Rate Across a Narrowed Orifice

Cited by 70 publications

References 13 publications

Influence of left ventricular relaxation on the pressure half time of aortic regurgitation

Influence of left ventricular relaxation on the pressure half time of aortic regurgitation

Algorithms for improving calculated streamlines in 3‐D phase contrast angiography

Hemielliptic Proximal Isovelocity Surface Area Method Modified for Clinical Application. More Accurate Quantification of Mitral Regurgitation in Doppler Echocardiography.

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