Flow Rate-Pressure Drop Relation in Coronary Angioplasty: Catheter Obstruction Effect

Back, L. H.; Kwack, E. Y.; Back, Martin R.

doi:10.1115/1.2795949

Cited by 55 publications

(44 citation statements)

References 17 publications

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“…It was suggested that a decline in pressure might be present in these diffusely diseased vessels without a focal stenosis (7,10). It was demonstrated that this decline is most likely no more than 0.12-0.25 mmHg/cm during maximal hyperemia (2,6). Therefore, it is conceivable that this limitation of the protocol did not influence the main conclusions drawn from this study.…”

Section: Discussionmentioning

confidence: 99%

Association between coronary lesion severity and distal microvascular resistance in patients with coronary artery disease

Chamuleau¹,

Siebes²,

Meuwissen³

et al. 2003

American Journal of Physiology-Heart and Circulatory Physiology

112

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Association between coronary lesion severity and distal microvascular resistance in patients with coronary artery disease. Am J Physiol Heart Circ Physiol 285: H2194-H2200, 2003. First published June 26, 2003 10.1152/ajpheart.01021.2002.-Homogeneity of microvascular resistance in different perfusion areas of the same heart is generally assumed. We investigated the effect of the severity of an epicardial stenosis on microvascular resistance in 27 patients with coronary artery disease and stable angina. All patients had an angiographically normal coronary artery, an artery with an intermediate lesion, and an artery with a severe lesion; the latter was treated with angioplasty. In each patient, distal blood flow velocity and pressure were measured during baseline and maximal hyperemia (induced by intracoronary adenosine) using a Doppler and pressure guide wire, respectively. The ratio of mean distal pressure to average peak blood flow velocity was used as an index for the microvascular resistance (MRv). Within patients, the hyperemic MRv was higher in arteries with more severe stenosis (P ϭ 0.021). After percutaneous transluminal coronary angioplasty (PTCA), the hyperemic MRv decreased (pre-PTCA, 2.6 vs. post-PTCA, 1.9 mmHg⅐cm Ϫ1 s Ϫ1, P Ͻ 0.01) toward the value of the reference artery (1.7 mmHg⅐cm Ϫ1 s Ϫ1; P ϭ 0.67). We conclude that there is a positive association between coronary lesion severity and variability of distal microvascular resistance that normalizes after angioplasty. This study challenges the concept of uniform distribution of hyperemic MRv that is relevant for the interpretation of both noninvasive and invasive diagnostic tests. microcirculation; coronary disease; physiology; blood flow; blood pressure SEVERAL INTRACORONARY-DERIVED physiological parameters have been introduced to characterize functional stenosis severity in patients with coronary artery disease, allowing clinical decision making during cardiac catheterization. These parameters are based on intracoronary pressure measurements (fractional flow reserve, FFR) or intracoronary-derived Doppler flow velocity measurements (coronary flow velocity reserve, CFVR) (13). Recently, our laboratory (14) has shown that variability in microvascular resistance between patients is responsible for discordant results between FFR and CFVR. High microvascular resistance was associated with a low CFVR and a high FFR, whereas low microvascular resistance was associated with a high CFVR and low FFR in patients with intermediate coronary lesions. Furthermore, homogeneity in the behavior of the myocardial resistance beds of the major perfusion areas within the same heart is assumed. This is of importance for the concept of relative CFVR. This assumption conflicts with the heterogeneity of myocardial blood flow found in different coronary perfusion areas in healthy volunteers (4). Recently, a paradoxical increase of microvascular resistance downstream from a severe coronary narrowing during tachycardia was reported (17), which was abolished after angioplasty. ...

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Section: Discussionmentioning

confidence: 99%

Association between coronary lesion severity and distal microvascular resistance in patients with coronary artery disease

Chamuleau¹,

Siebes²,

Meuwissen³

et al. 2003

American Journal of Physiology-Heart and Circulatory Physiology

112

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“…It has been demonstrated in vitro and in vivo that the relationship between stenosis pressure drop and flow (or velocity) is nonlinear and is described by ⌬p ϭ aV ϩ bV 2 , where a and b are stenosis specific constants and V is the velocity. The term aV refers to viscous losses and bV 2 momentum losses associated with the flow due to the presence of a stenosis (obstruction).…”

Section: Pressure Drop Coefficientmentioning

confidence: 99%

Influence of heart rate on fractional flow reserve, pressure drop coefficient, and lesion flow coefficient for epicardial coronary stenosis in a porcine model

Kolli

Banerjee

Peelukhana

et al. 2011

American Journal of Physiology-Heart and Circulatory Physiology

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Gottliebson WM, Effat MA. Influence of heart rate on fractional flow reserve, pressure drop coefficient, and lesion flow coefficient for epicardial coronary stenosis in a porcine model. Am J Physiol Heart Circ Physiol 300: H382-H387, 2011. First published October 8, 2010 doi:10.1152/ajpheart.00412.2010.-A limitation in the use of invasive coronary diagnostic indexes is that fluctuations in hemodynamic factors such as heart rate (HR), blood pressure, and contractility may alter resting or hyperemic flow measurements and may introduce uncertainties in the interpretation of these indexes. In this study, we focused on the effect of fluctuations in HR and area stenosis (AS) on diagnostic indexes. We hypothesized that the pressure drop coefficient (CDPe, ratio of transstenotic pressure drop and distal dynamic pressure), lesion flow coefficient (LFC, square root of ratio of limiting value CDP and CDP at site of stenosis) derived from fluid dynamics principles, and fractional flow reserve (FFR, ratio of average distal and proximal pressures) are independent of HR and can significantly differentiate between the severity of stenosis. Cardiac catheterization was performed on 11 Yorkshire pigs. Simultaneous measurements of distal coronary arterial pressure and flow were performed using a dual sensor-tipped guidewire for HR Ͻ 120 and HR Ͼ 120 beats/min, in the presence of epicardial coronary lesions of Ͻ50% AS and Ͼ50% AS. The mean values of FFR, CDPe, and LFC were significantly different (P Ͻ 0.05) for lesions of Ͻ50% AS and Ͼ50% AS (0.88 Ϯ 0.04, 0.76 Ϯ 0.04; 62 Ϯ 30, 151 Ϯ 35, and 0.10 Ϯ 0.02 and 0.16 Ϯ 0.01, respectively). The mean values of FFR and CDPe were not significantly different (P Ͼ 0.05) for variable HR conditions of HR Ͻ 120 and HR Ͼ 120 beats/min (FFR, 0.81 Ϯ 0.04 and 0.82 Ϯ 0.04; and CDPe, 95 Ϯ 33 and 118 Ϯ 36). The mean values of LFC do somewhat vary with HR (0.14 Ϯ 0.01 and 0.12 Ϯ 0.02). In conclusion, fluctuations in HR have no significant influence on the measured values of CDP e and FFR but have a marginal influence on the measured values of LFC. However, all three parameters can significantly differentiate between stenosis severities. These results suggest that the diagnostic parameters can be potentially used in a better assessment of coronary stenosis severity under a clinical setting. coronary disease; hemodynamics; catheterization CORONARY ANGIOGRAPHY is the current gold standard for detecting epicardial coronary artery disease. Augmenting this anatomical data with coronary functional parameters (pressure, flow, and/or velocity) provides unique information that facilitates fully informed therapeutic decision making in the catheterization laboratory. Several invasive functional approaches have been used for the past several years within the cardiac catheterization laboratory that allow for a determination of the functional significance of epicardial coronary stenoses. These methods include measurement of coronary flow reserve [CFR, the ratio of hyperemic flow to basal flow (10) (9), an advanced func...

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“…19 In addition, instead of diastolic portions of selected cycles during the hyperemic response, we used successive per-beat averages to generate the pressuredrop-flow relationship of a coronary stenosis from baseline throughout maximal hyperemia. 10,17 The main advantages are easier postprocessing with less user interaction, which circumvents problems related to phase delays between the pressure transducers, the characterization of stenosis hemodynamics over the entire range of possible flow velocities, and the ability to identify partially compliant lesions.…”

Section: Interpretation Of the Pressure-gradient-flowvelocity Relatiomentioning

confidence: 99%

Single-Wire Pressure and Flow Velocity Measurement to Quantify Coronary Stenosis Hemodynamics and Effects of Percutaneous Interventions

et al. 2004

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Background-Lack of high-fidelity simultaneous measurements of pressure and flow velocity distal to a coronary artery stenosis has hampered the study of stenosis pressure drop-velocity (⌬P-v) relationships in patients. Methods and Results-A novel 0.014-inch dual-sensor (pressure and Doppler velocity) guidewire was used in 15 coronary lesions to obtain per-beat averages of pressure drop and velocity after an intracoronary bolus of adenosine. ⌬P-v relations from resting to maximal hyperemic velocity were constructed before and after stepwise executed percutaneous coronary intervention (PCI). Before PCI, half of the ⌬P-v relations revealed the presence of a compliant stenosis, which was stabilized by angioplasty. Fractional flow reserve (FFR), coronary flow reserve (CFVR), and velocity-based indices of stenosis resistance (h-SRv) and microvascular resistance (h-MRv) at maximal hyperemia were compared. Stepwise PCI significantly lowered h-SRv, with an initial marked reduction in hyperemic pressure drop followed by further gains in velocity. A concomitant significant reduction of h-MRv accounted for half of the gain in velocity after PCI.

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Flow Rate-Pressure Drop Relation in Coronary Angioplasty: Catheter Obstruction Effect

Cited by 55 publications

References 17 publications

Association between coronary lesion severity and distal microvascular resistance in patients with coronary artery disease

Association between coronary lesion severity and distal microvascular resistance in patients with coronary artery disease

Influence of heart rate on fractional flow reserve, pressure drop coefficient, and lesion flow coefficient for epicardial coronary stenosis in a porcine model

Single-Wire Pressure and Flow Velocity Measurement to Quantify Coronary Stenosis Hemodynamics and Effects of Percutaneous Interventions

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