Influence of coronary collateral flow on coronary diagnostic parameters: An in vitro study

Peelukhana, Srikara V.; Back, L. H.; Banerjee, Rupak K.

doi:10.1016/j.jbiomech.2009.08.013

Cited by 37 publications

(31 citation statements)

References 39 publications

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“…In a recent study employing a mock circulation, collateral flow could be measured directly (23). At FFR ϭ 0.74, the maximal collateral contribution to total microvascular flow did not exceed 8%.…”

Section: Discussionmentioning

confidence: 95%

“…Moreover, a recent study reported a large overlap in thermodilution-based IMR between patients with and without epicardial atherosclerosis (18). Clinical decision making could be fine tuned by a HMR determination in the sense that in the presence of higher microvascular resistance, which leads to a higher value of FFR, PCI would be advised at a higher level than with lower HMR (23). This agrees with our earlier conclusion that HMR plays a role in the disparity between FFR and coronary flow velocity reserve (20).…”

Section: Discussionmentioning

confidence: 99%

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Minimal effect of collateral flow on coronary microvascular resistance in the presence of intermediate and noncritical coronary stenoses

Verhoeff

Hoef

Spaan

et al. 2012

American Journal of Physiology-Heart and Circulatory Physiology

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-Depending on stenosis severity, collateral flow can be a confounding factor in the determination of coronary hyperemic microvascular resistance (HMR). Under certain assumptions, the calculation of HMR can be corrected for collateral flow by incorporating the wedge pressure (P w) in the calculation. However, although P w Ͼ 25 mmHg is indicative of collateral flow, Pw does in part also reflect myocardial wall stress neglected in the assumptions. Therefore, the aim of this study was to establish whether adjusting HMR by P w is pertinent for a diagnostically relevant range of stenosis severities as expressed by fractional flow reserve (FFR). Accordingly, intracoronary pressure and Doppler flow velocity were measured a total of 95 times in 29 patients distal to a coronary stenosis before and after stepwise percutaneous coronary intervention. HMR was calculated without (HMR) and with Pw-based adjustment for collateral flow (HMRC). FFR ranged from 0.3 to 1. HMR varied between 1 and 5 and HMRC between 0.5 and 4.2 mmHg·cm Ϫ1 ·s. HMR was about 37% higher than HMRC for stenoses with FFR Ͻ 0.6, but for FFR Ͼ 0.8, the relative difference was reduced to 4.4 Ϯ 3.4%. In the diagnostically relevant range of FFR between 0.6 and 0.8, this difference was 16.5 Ϯ 10.4%. In conclusion, P w-based adjustment likely overestimates the effect of potential collateral flow and is not needed for the assessment of coronary HMR in the presence of a flow-limiting stenosis characterized by FFR between 0.6 and 0.8 or for nonsignificant lesions. wedge pressure; fractional flow reserve; coronary circulation CORONARY MICROVASCULAR DYSFUNCTION is increasingly being recognized as a major contributor to myocardial ischemia (3) and is likely associated with an altered coronary hyperemic microvascular resistance (HMR). Hence, a reliable assessment of microvascular resistance is needed that accurately reflects the status of the microcirculation and supports further development of diagnostic tools for microvascular disease.Resistance of a vascular compartment is defined as the ratio between the pressure drop over it and flow through it. Application of the resistance concept to the coronary circulation is challenging in the clinical setting, since volume flow cannot practically be measured directly and coronary back pressure is governed by multiple factors including microvascular conductance and extravascular compressive forces (16,17,32,37). At present, two guidewire-based systems are capable of the combined measurement of pressure and a surrogate of flow through a coronary stenosis. In the first system, flow velocity is measured by a Doppler crystal next to a pressure sensor (31, 35). The second system exploits the temperature sensitivity of the pressure sensor to determine the mean transit time of a temperature change induced by a bolus of saline (10). The corresponding indexes of HMR are respectively defined as the mean distal pressure (P d ) divided by mean distal flow velocity (35) The entrance of the microcirculation is not uniquely defined. Colla...

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Section: Discussionmentioning

confidence: 95%

Section: Discussionmentioning

confidence: 99%

Minimal effect of collateral flow on coronary microvascular resistance in the presence of intermediate and noncritical coronary stenoses

Verhoeff

Hoef

Spaan

et al. 2012

American Journal of Physiology-Heart and Circulatory Physiology

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“…7]. These parameters have been validated extensively both in vitro (3,5,7,32) and in vivo (4,19,20,40) and tested for delineating different levels of ES (19,40). More importantly, these parameters have been shown to delineate between the ES and MVD (4,20).…”

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confidence: 99%

Effect of heart rate on hemodynamic endpoints under concomitant microvascular disease in a porcine model

Peelukhana

Banerjee

Kolli

et al. 2012

American Journal of Physiology-Heart and Circulatory Physiology

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Diagnosis of the ischemic power of epicardial stenosis with concomitant microvascular disease (MVD) is challenging during coronary interventions, especially under variable hemodynamic factors like heart rate (HR). The goal of this study is to assess the influence of variable HR and percent area stenosis (%AS) in the presence of MVD on pressure drop coefficient (CDP; ratio of transstenotic pressure drop to the distal dynamic pressure) and lesion flow coefficient (LFC; ratio of %AS to the CDP at the throat region). We hypothesize that CDP and LFC are independent of HR. %AS and MVD were created using angioplasty balloons and 90-m microspheres, respectively. Simultaneous measurements of pressure drop (DP) and velocity were done in 11 Yorkshire pigs. Fractional flow reserve (FFR), CDP, and LFC were calculated for the groups HR Ͻ 120 and HR Ͼ 120 beats/min, %AS Ͻ 50 and %AS Ͼ 50, and additionally for DP Ͻ 14 and DP Ͼ 14 mmHg, and analyzed using regression and ANOVA analysis. Regression analysis showed independence between HR and the FFR, CDP, and LFC while it showed dependence between %AS and the FFR, CDP, and LFC. In the ANOVA analysis, for the HR Ͻ 120 beats/min and HR Ͼ 120 beats/min groups, the values of FFR (0.82 Ϯ 0.02 and 0.82 Ϯ 0.02), CDP (83.15 Ϯ 26.19 and 98.62 Ϯ 26.04), and LFC (0.16 Ϯ 0.03 and 0.15 Ϯ 0.03) were not significantly different (P Ͼ 0.05). However, for %AS Ͻ 50 and %AS Ͼ 50, the FFR (0.89 Ϯ 0.02 and 0.75 Ϯ 0.02), CDP (35.97 Ϯ 25.79.10 and 143.80 Ϯ 25.41), and LFC (0.09 Ϯ 0.03 and 0.22 Ϯ 0.03) were significantly different (P Ͻ 0.05). A similar trend was observed between the DP groups. Under MVD conditions, FFR, CDP, and LFC were not significantly influenced by changes in HR, while they can significantly distinguish %AS and DP groups.

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“…The CDP e , readily obtained during routine cardiac catheterization procedures, has been recently validated for in vitro (4,21) and in vivo (3,5,28) studies. LFC, a novel index that combines both functional and anatomical measurements, has also been validated in preclinical studies for determining the severity of epicardial stenosis under normal microcirculation (28).…”

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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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Influence of coronary collateral flow on coronary diagnostic parameters: An in vitro study

Cited by 37 publications

References 39 publications

Minimal effect of collateral flow on coronary microvascular resistance in the presence of intermediate and noncritical coronary stenoses

Minimal effect of collateral flow on coronary microvascular resistance in the presence of intermediate and noncritical coronary stenoses

Effect of heart rate on hemodynamic endpoints under concomitant microvascular disease in a porcine model

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

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