Assessment of coronary stenoses by Doppler wires: A validation study using in vitro modeling and computer simulations

Porenta, G; Schima, H; Pentaris, A; Tsangaris, S; Moertl, D; Probst, P; Maurer, G; Baumgartner, H

dc.contributor.author	Porenta, G	en
dc.contributor.author	Schima, H	en
dc.contributor.author	Pentaris, A	en
dc.contributor.author	Tsangaris, S	en
dc.contributor.author	Moertl, D	en
dc.contributor.author	Probst, P	en
dc.contributor.author	Maurer, G	en
dc.contributor.author	Baumgartner, H	en
dc.date.accessioned	2014-03-01T01:14:26Z
dc.date.available	2014-03-01T01:14:26Z
dc.date.issued	1999	en
dc.identifier.issn	0301-5629	en
dc.identifier.uri	https://dspace.lib.ntua.gr/xmlui/handle/123456789/13060
dc.subject	Coronary artery disease	en
dc.subject	Coronary flow	en
dc.subject	Doppler ultrasound	en
dc.subject.classification	Acoustics	en
dc.subject.classification	Radiology, Nuclear Medicine & Medical Imaging	en
dc.subject.other	Blood vessels	en
dc.subject.other	Computer simulation	en
dc.subject.other	Diseases	en
dc.subject.other	Doppler effect	en
dc.subject.other	Errors	en
dc.subject.other	Hemodynamics	en
dc.subject.other	Laminar flow	en
dc.subject.other	Coronary artery disease	en
dc.subject.other	Coronary flow	en
dc.subject.other	Doppler ultrasound	en
dc.subject.other	Doppler wires	en
dc.subject.other	Ultrasonic velocity measurement	en
dc.subject.other	article	en
dc.subject.other	blood flow velocity	en
dc.subject.other	computer simulation	en
dc.subject.other	coronary artery blood flow	en
dc.subject.other	coronary artery obstruction	en
dc.subject.other	disease severity	en
dc.subject.other	doppler flowmetry	en
dc.subject.other	flow rate	en
dc.subject.other	guide wire	en
dc.subject.other	laminar flow	en
dc.subject.other	priority journal	en
dc.subject.other	Analysis of Variance	en
dc.subject.other	Blood Flow Velocity	en
dc.subject.other	Computer Simulation	en
dc.subject.other	Coronary Disease	en
dc.subject.other	Humans	en
dc.subject.other	Models, Cardiovascular	en
dc.subject.other	Regression Analysis	en
dc.subject.other	Transducers	en
dc.subject.other	Ultrasonography, Doppler	en
dc.title	Assessment of coronary stenoses by Doppler wires: A validation study using in vitro modeling and computer simulations	en
heal.type	journalArticle	en
heal.identifier.primary	10.1016/S0301-5629(99)00033-2	en
heal.identifier.secondary	http://dx.doi.org/10.1016/S0301-5629(99)00033-2	en
heal.language	English	en
heal.publicationDate	1999	en
heal.abstract	The present study evaluates the use of intracoronary velocity measurements by Doppler guidewires for assessing coronary obstructions. In vitro experiments were performed in a flow model using acrylic phantoms of coronary stenoses with different configurations (stenosis area: 56%, 75% and 89%; stenosis length: 1 and 5 mm; stenosis border: tapering or abrupt). Nonpulsatile laminar flow conditions of a test fluid were established at flow rates ranging from 0.5 to 2.0 mL/s to simulate baseline flow and flow after vasodilation. Peak Doppler velocity was measured proximal to, within and distal to the model stenoses. Computer simulations were employed to calculate radial flow profiles with and without a Doppler wire aligned with the vessel center. In 84 in vitro flow experiments, peak Doppler velocity correlated well with the average flow velocity as calculated from the actual flow rate and the vessel's cross-sectional area proximal to (r = 0.98, SEE = 1.4, p < 0.001) and within (r = 0.97, SEE = 16.4, p < 0.001) the stenosis. However, the ratio of calculated average velocity to Doppler-measured peak velocity was significantly different from 0.5, the expected value for a parabolic flow profile (0.76 ± 0.08, 0.81 ± 0.14; p < 0.001). Acceptable accuracy was found for the Doppler estimation of stenosis severity using the continuity equation (error: 0.9 ± 1.2% and -4.6 ± 3.5% for stenosis with a length of 5 mm and 1 mm, respectively). Doppler velocity reserve significantly underestimated the true flow reserve for the 56% and 75% stenoses (p < 0.01). Computer simulations demonstrated significant alterations of flow profiles by the wire, which explained the observed underestimation of the true flow reserve by the Doppler velocity reserve. Thus, Doppler guidewire measurements of intracoronary flow velocities are useful to assess the severity of coronary stenoses. However, the in vitro results and computer simulations indicate that guidewires alter the flow profile, so that Doppler velocity reserve may underestimate the true flow reserve.The present study evaluates the use of intracoronary velocity measurements by Doppler guidewires for assessing coronary obstructions. In vitro experiments were performed in a flow model using acrylic phantoms of coronary stenoses with different configurations (stenosis area: 56%, 75% and 89%; stenosis length: 1 and 5 mm; stenosis border: tapering or abrupt). Nonpulsatile laminar flow conditions of a test fluid were established at flow rates ranging from 0.5 to 2.0 mL/s to simulate baseline flow and flow after vasodilation. Peak Doppler velocity was measured proximal to, within and distal to the model stenoses. Computer simulations were employed to calculate radial flow profiles with and without a Doppler wire aligned with the vessel center. In 84 in vitro flow experiments, peak Doppler velocity correlated well with the average flow velocity as calculated from the actual flow rate and the vessel's cross-sectional area proximal to (r = 0.98, SEE = 1.4, p < 0.001) and within (r = 0.97, SEE = 16.4, p < 0.001) the stenosis. However, the ratio of calculated average velocity to Doppler-measured peak velocity was significantly different from 0.5, the expected value for a parabolic flow profile (0.76 ± 0.08, 0.81 ± 0.14; p < 0.001). Acceptable accuracy was found for the Doppler estimation of stenosis severity using the continuity equation (error: 0.9 ± 1.2% and -4.6 ± 3.5% for stenosis with a length of 5 mm and 1 mm, respectively). Doppler velocity reserve significantly underestimated the true flow reserve for the 56% and 75% stenoses (p < 0.01). Computer simulations demonstrated significant alterations of flow profiles by the wire, which explained the observed underestimation of the true flow reserve by the Doppler velocity reserve. Thus, Doppler guidewire measurements of intracoronary flow velocities are useful to assess the severity of coronary stenoses. However, the in vitro results and computer simulations indicate that guidewires alter the flow profile, so that Doppler velocity reserve may underestimate the true flow reserve.	en
heal.publisher	Elsevier Science Ltd, Exeter, United Kingdom	en
heal.journalName	Ultrasound in Medicine and Biology	en
dc.identifier.doi	10.1016/S0301-5629(99)00033-2	en
dc.identifier.isi	ISI:000080820100009	en
dc.identifier.volume	25	en
dc.identifier.issue	5	en
dc.identifier.spage	793	en
dc.identifier.epage	801	en