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Quantification of fractional flow reserve based on angiographic image data.

Wong JT, Le H, Suh WM, Chalyan DA, Mehraien T, Kern MJ, Kassab GS, Molloi S - Int J Cardiovasc Imaging (2011)

Bottom Line: Pressure-wire measurements of FFR (FFR( P )) correlated linearly with angiographic volume-derived measurements of FFR (FFR( V )) according to the equation: FFR( P ) = 0.41 FFR( V ) + 0.52 (P-value < 0.001).The correlation coefficient and standard error of estimate were 0.85 and 0.07, respectively.This is the first study to provide an angiographic method to quantify FFR in swine.

View Article: PubMed Central - PubMed

Affiliation: Department of Radiological Sciences, Medical Sciences I, B-140, University of California, Irvine, CA 92697, USA.

ABSTRACT
Coronary angiography provides excellent visualization of coronary arteries, but has limitations in assessing the clinical significance of a coronary stenosis. Fractional flow reserve (FFR) has been shown to be reliable in discerning stenoses responsible for inducible ischemia. The purpose of this study is to validate a technique for FFR quantification using angiographic image data. The study was carried out on 10 anesthetized, closed-chest swine using angioplasty balloon catheters to produce partial occlusion. Angiography based FFR was calculated from an angiographically measured ratio of coronary blood flow to arterial lumen volume. Pressure-based FFR was measured from a ratio of distal coronary pressure to aortic pressure. Pressure-wire measurements of FFR (FFR( P )) correlated linearly with angiographic volume-derived measurements of FFR (FFR( V )) according to the equation: FFR( P ) = 0.41 FFR( V ) + 0.52 (P-value < 0.001). The correlation coefficient and standard error of estimate were 0.85 and 0.07, respectively. This is the first study to provide an angiographic method to quantify FFR in swine. Angiographic FFR can potentially provide an assessment of the physiological severity of a coronary stenosis during routine diagnostic cardiac catheterization without a need to cross a stenosis with a pressure-wire.

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Pooled data showing the relation between simplified myocardial fractional flow reserve (Pd/Pa) and direct flow reserve (QS/QN) in swine. Open circles represent data from the current study where FFRP is (Pd/Pa) and FFRQ is equivalent to (QS/QN). Closed triangles are extracted from published data by Pantely et al. [32, 34, 35] where blood flow was measured with Doppler flow probe
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Fig6: Pooled data showing the relation between simplified myocardial fractional flow reserve (Pd/Pa) and direct flow reserve (QS/QN) in swine. Open circles represent data from the current study where FFRP is (Pd/Pa) and FFRQ is equivalent to (QS/QN). Closed triangles are extracted from published data by Pantely et al. [32, 34, 35] where blood flow was measured with Doppler flow probe

Mentions: The observed highly correlated, but non-identical, relationship between FFRP and FFRV in Fig. 4 is in accordance with flow-pressure relationships. For example, previous studies have shown that the coronary pressure-flow curve is convex rather than linear, where flow drops off more rapidly than pressure at low pressure or flow states [32]. The observed nonlinearity stems from the compliance or elasticity of coronary vessels as they respond to the decreasing distending pressures distal to the stenosis [33]. Figure 6 plots the data from Pantely et al. [32, 34, 35] in the form of pressure- and flow-derived FFR values. The FFR values plotted in Fig. 6 were determined using their raw distal pressure and flow measurements normalized by maximum pressure and flow measurements to reflect Pa and QN values, respectively. Figure 6 clearly shows the nonlinearly between Pd/Pa and QS/QN. The experimentally measured FFRP (which is Pd/Pa) and FFRQ (which is equivalent to QS/QN) were also included in Fig. 6 in order to demonstrate that the experimentally observed relationship is consistent with previous flow and pressure results. Figure 6 also shows that the relationship between Pd/Pa and QS/QN is approximately linear for values greater 0.2, which is important since coronary stenoses with FFR values less than 0.2 do not require FFR measurement for intervention. An extrapolation of data in this linear portion would lead to the observed 0.49 y-intercept. Previous studies have found similar overestimations of the pressure intercept when considering the same range of pressures and flows [32, 34, 35].Fig. 6


Quantification of fractional flow reserve based on angiographic image data.

Wong JT, Le H, Suh WM, Chalyan DA, Mehraien T, Kern MJ, Kassab GS, Molloi S - Int J Cardiovasc Imaging (2011)

Pooled data showing the relation between simplified myocardial fractional flow reserve (Pd/Pa) and direct flow reserve (QS/QN) in swine. Open circles represent data from the current study where FFRP is (Pd/Pa) and FFRQ is equivalent to (QS/QN). Closed triangles are extracted from published data by Pantely et al. [32, 34, 35] where blood flow was measured with Doppler flow probe
© Copyright Policy
Related In: Results  -  Collection

Show All Figures
getmorefigures.php?uid=PMC3094747&req=5

Fig6: Pooled data showing the relation between simplified myocardial fractional flow reserve (Pd/Pa) and direct flow reserve (QS/QN) in swine. Open circles represent data from the current study where FFRP is (Pd/Pa) and FFRQ is equivalent to (QS/QN). Closed triangles are extracted from published data by Pantely et al. [32, 34, 35] where blood flow was measured with Doppler flow probe
Mentions: The observed highly correlated, but non-identical, relationship between FFRP and FFRV in Fig. 4 is in accordance with flow-pressure relationships. For example, previous studies have shown that the coronary pressure-flow curve is convex rather than linear, where flow drops off more rapidly than pressure at low pressure or flow states [32]. The observed nonlinearity stems from the compliance or elasticity of coronary vessels as they respond to the decreasing distending pressures distal to the stenosis [33]. Figure 6 plots the data from Pantely et al. [32, 34, 35] in the form of pressure- and flow-derived FFR values. The FFR values plotted in Fig. 6 were determined using their raw distal pressure and flow measurements normalized by maximum pressure and flow measurements to reflect Pa and QN values, respectively. Figure 6 clearly shows the nonlinearly between Pd/Pa and QS/QN. The experimentally measured FFRP (which is Pd/Pa) and FFRQ (which is equivalent to QS/QN) were also included in Fig. 6 in order to demonstrate that the experimentally observed relationship is consistent with previous flow and pressure results. Figure 6 also shows that the relationship between Pd/Pa and QS/QN is approximately linear for values greater 0.2, which is important since coronary stenoses with FFR values less than 0.2 do not require FFR measurement for intervention. An extrapolation of data in this linear portion would lead to the observed 0.49 y-intercept. Previous studies have found similar overestimations of the pressure intercept when considering the same range of pressures and flows [32, 34, 35].Fig. 6

Bottom Line: Pressure-wire measurements of FFR (FFR( P )) correlated linearly with angiographic volume-derived measurements of FFR (FFR( V )) according to the equation: FFR( P ) = 0.41 FFR( V ) + 0.52 (P-value < 0.001).The correlation coefficient and standard error of estimate were 0.85 and 0.07, respectively.This is the first study to provide an angiographic method to quantify FFR in swine.

View Article: PubMed Central - PubMed

Affiliation: Department of Radiological Sciences, Medical Sciences I, B-140, University of California, Irvine, CA 92697, USA.

ABSTRACT
Coronary angiography provides excellent visualization of coronary arteries, but has limitations in assessing the clinical significance of a coronary stenosis. Fractional flow reserve (FFR) has been shown to be reliable in discerning stenoses responsible for inducible ischemia. The purpose of this study is to validate a technique for FFR quantification using angiographic image data. The study was carried out on 10 anesthetized, closed-chest swine using angioplasty balloon catheters to produce partial occlusion. Angiography based FFR was calculated from an angiographically measured ratio of coronary blood flow to arterial lumen volume. Pressure-based FFR was measured from a ratio of distal coronary pressure to aortic pressure. Pressure-wire measurements of FFR (FFR( P )) correlated linearly with angiographic volume-derived measurements of FFR (FFR( V )) according to the equation: FFR( P ) = 0.41 FFR( V ) + 0.52 (P-value < 0.001). The correlation coefficient and standard error of estimate were 0.85 and 0.07, respectively. This is the first study to provide an angiographic method to quantify FFR in swine. Angiographic FFR can potentially provide an assessment of the physiological severity of a coronary stenosis during routine diagnostic cardiac catheterization without a need to cross a stenosis with a pressure-wire.

Show MeSH
Related in: MedlinePlus