Functional diagnosis of coronary stenoses using pressure drop coefficient: A pilot study in humans

Kolli, Kranthi K.; Helmy, Tarek; Peelukhana, Srikara V.; Arif, Imran; Leesar, Massoud A.; Back, L. H.; Banerjee, Rupak K.; Effat, Mohamed

doi:10.1002/ccd.25085

Cited by 16 publications

(19 citation statements)

References 31 publications

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“…Based on fluid mechanics fundamentals, pressure drop is linearly correlated with flow in vessels with mild stenosis severity, whereas it is a quadratic function of flow for significant lesions. Based on this concept, the new diagnostic endpoints were mainly defined by scaling translesional pressure drop with either linear or quadratic forms of flow (14)(15)(16)(17). These new parameters have been shown to provide better delineation of stenosis severity, microvascular diseases, multiple coronary stenoses, etc.…”

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confidence: 99%

Functional Diagnostic Parameters for Arteriovenous Fistula

Rajabi-Jagahrgh

Banerjee

2015

Artificial Organs

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The inability to detect the arteriovenous fistula (AVF) dysfunction in a timely manner under the current surveillance programs, which are based on either diameter (d), flow rate (Q), or pressure (p) measurements, is one of the major challenges of dialysis treatment. Thus, our aim is to introduce new functional diagnostic parameters that can better predict AVF functionality status. Six AVFs were created between the femoral arteries and veins of three pigs, each pig having two AVFs on either limb. Flow fields and pressure drop (Δp) in AVFs were obtained via numerical analysis utilizing the CT scan and Doppler ultrasound data at 2D (D: days), 7D, and 28D postsurgery. The dataset included 16 (two pigs [four AVFs] for three time points, and one pig [two AVFs] for two time points) repeated measurements over time, and the statistical analysis was done using a mixed model. To evaluate the nature of pressure drop-flow relationships in AVFs, the Δp was correlated with the average velocity at proximal artery (v) and also the corresponding scaled velocity (v*) by the curvature ratio of anastomotic segment. Based on these relationships, two new functional diagnostic parameters, including the nonlinear pressure drop coefficient (Cp ; pressure drop divided by dynamic pressure at proximal artery) and the linear resistance index (R; pressure drop divided by velocity at proximal artery), were introduced. The diagnostic parameters that were calculated based on scaled velocity are represented as R* and Cp *. A marginal (P = 0.1) increase in d from 2D (5.4 ± 0.7 mm) to 7D (6.8 ± 0.7 mm), along with a significant increase in Q (2D: 967 ± 273 mL/min; 7D: 1943 ± 273 mL/min), was accompanied by an almost unchanged Δp over this time period (2D: 16.42 ± 4.6 mm Hg; 7D: 16.40 ± 4.6 mm Hg). However, the insignificant increase in d and Q from 7D to 28D (d = 7.8 ± 0.8 mm; Q = 2181 ± 378 mL/min) was accompanied by the elevation in Δp (24.6 ± 6.5 mm Hg). The functional diagnostic parameters, R and Cp , decreased from 2D (R = 22.4 ± 2.8 mm Hg/m/s; Cp = 12.0 ± 2.6) to 7D (R = 20.8 ± 2.8 mm Hg/m/s; Cp = 8.1 ± 2.6), and then increased from 7D to 28D (R = 35.5 ± 5.7 mm Hg/m/s; Cp = 17.5 ± 3.6) with a marginal significance. However, when the scaled velocity was used to calculate R* and Cp *, the increase in diagnostic parameters from 7D to 28D achieved statistical significance (P < 0.05). In summary, although the differences in the hemodynamic parameters (d, Q, and Δp) from 7D to 28D were insignificant, changes in their combined effects in the form of diagnostic parameters were significant. Therefore, the functional diagnostic parameters are capable of better distinguishing changes in the hemodynamic variations, and thus, could be promising endpoints to diagnose the functionality of AVFs over time.

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confidence: 99%

Functional Diagnostic Parameters for Arteriovenous Fistula

Rajabi-Jagahrgh

Banerjee

2015

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“…In general, as the severity of a single stenosis was varied, CDP was shown to change by a few orders (range: 0-1000) of magnitude [21,49,51,52]. Furthermore, CDP was shown to delineate the severity of epicardial stenosis under a clinical setting [25]. In the presence of a serial downstream stenosis, CDP values showed no specific trend or relative variation for the upstream severe stenosis, while the values for the upstream mild and intermediate stenosis showed an insignificant increasing trend with the increase in downstream severity, when evaluated under C1 condition.…”

Section: Discussionmentioning

confidence: 98%

“…Simultaneous measurements of functional parameters (pressure drop and proximal velocity), necessary for the evaluation of CDP, can be readily obtained during routine cardiac catheterization procedures using a dual-sensor tipped guidewire, also known as a combowire [23][24][25][26][27]. CDP has been validated in pre-clinical trials [21,23,24,26,27] and under a clinical setting [25], in order to delineate epicardial stenoses. Furthermore, it has been shown to be independent of heart rate [24,26] and contractility [27,28] in recently conducted in vivo animal studies.…”

Section: Introductionmentioning

confidence: 99%

“…CDP is defined as the ratio of the trans-stenotic pressure drop to the dynamic pressure proximal to a stenosis [22]. Simultaneous measurements of functional parameters (pressure drop and proximal velocity), necessary for the evaluation of CDP, can be readily obtained during routine cardiac catheterization procedures using a dual-sensor tipped guidewire, also known as a combowire [23][24][25][26][27]. CDP has been validated in pre-clinical trials [21,23,24,26,27] and under a clinical setting [25], in order to delineate epicardial stenoses.…”

Section: Introductionmentioning

confidence: 99%

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Diagnostic Uncertainties During Assessment of Serial Coronary Stenoses: An In Vitro Study

D’Souza

Peelukhana

Banerjee

2014

Journal of Biomechanical Engineering

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Currently, the diagnosis of coronary stenosis is primarily based on the well-established functional diagnostic parameter, fractional flow reserve (FFR: ratio of pressures distal and proximal to a stenosis). The threshold of FFR has a "gray" zone of 0.75-0.80, below which further clinical intervention is recommended. An alternate diagnostic parameter, pressure drop coefficient (CDP: ratio of trans-stenotic pressure drop to the proximal dynamic pressure), developed based on fundamental fluid dynamics principles, has been suggested by our group. Additional serial stenosis, present downstream in a single vessel, reduces the hyperemic flow, Q˜h, and pressure drop, Δp˜, across an upstream stenosis. Such hemodynamic variations may alter the values of FFR and CDP of the upstream stenosis. Thus, in the presence of serial stenoses, there is a need to evaluate the possibility of misinterpretation of FFR and test the efficacy of CDP of individual stenoses. In-vitro experiments simulating physiologic conditions, along with human data, were used to evaluate nine combinations of serial stenoses. Different cases of upstream stenosis (mild: 64% area stenosis (AS) or 40% diameter stenosis (DS); intermediate: 80% AS or 55% DS; and severe: 90% AS or 68% DS) were tested under varying degrees of downstream stenosis (mild, intermediate, and severe). The pressure drop-flow rate characteristics of the serial stenoses combinations were evaluated for determining the effect of the downstream stenosis on the upstream stenosis. In general, Q˜h and Δp˜ across the upstream stenosis decreased when the downstream stenosis severity was increased. The FFR of the upstream mild, intermediate, and severe stenosis increased by a maximum of 3%, 13%, and 19%, respectively, when the downstream stenosis severity increased from mild to severe. The FFR of a stand-alone intermediate stenosis under a clinical setting is reported to be ∼0.72. In the presence of a downstream stenosis, the FFR values of the upstream intermediate stenosis were either within (0.77 for 80%-64% AS and 0.79 for 80%-80% AS) or above (0.88 for 80%-90% AS) the "gray" zone (0.75-0.80). This artificial increase in the FFR value within or above the "gray" zone for an upstream intermediate stenosis when in series with a clinically relevant downstream stenosis could lead to misinterpretation of functional stenosis severity. In contrast, a distinct range of CDP values was observed for each case of upstream stenosis (mild: 8-10; intermediate: 47-54; and severe: 130-155). The nonoverlapping range of CDP could better delineate the effect of the downstream stenosis from the upstream stenosis and allow for the accurate diagnosis of the functional severity of the upstream stenosis.

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“…The CDP was validated in in vitro , and in vivo animal studies to differentiate between epicardial stenosis and microvascular dysfunction. Further, in a recent pilot clinical study CDP has been shown in a patient population to distinguish between degrees of stenosis severity.…”

Section: Introductionmentioning

confidence: 99%

Diagnostic cutoff for pressure drop coefficient in relation to fractional flow reserve and coronary flow reserve: A Patient‐Level Analysis

Kolli

Hoef

Effat

et al. 2015

Cathet Cardio Intervent

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Functional diagnosis of coronary stenoses using pressure drop coefficient: A pilot study in humans

Abstract: CDP, a nondimensional parameter combining simultaneous measurements of pressure drop and velocity data, can accurately define the severity of coronary stenoses and could prove advantageous clinically.

Cited by 16 publications

References 31 publications

Functional Diagnostic Parameters for Arteriovenous Fistula

Functional Diagnostic Parameters for Arteriovenous Fistula

Diagnostic Uncertainties During Assessment of Serial Coronary Stenoses: An In Vitro Study

Diagnostic cutoff for pressure drop coefficient in relation to fractional flow reserve and coronary flow reserve: A Patient‐Level Analysis

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