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Banerjee RK, Ramadurai S, Manegaonkar SM, Rao MB, Rakkimuthu S, Effat MA. Comparison Between 5- and 1-Year Outcomes Using Cutoff Values of Pressure Drop Coefficient and Fractional Flow Reserve for Diagnosing Coronary Artery Diseases. Front Physiol 2021; 12:689517. [PMID: 34335296 PMCID: PMC8317064 DOI: 10.3389/fphys.2021.689517] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/01/2021] [Accepted: 05/28/2021] [Indexed: 12/02/2022] Open
Abstract
Background The current pressure-based coronary diagnostic index, fractional flow reserve (FFR), has a limited efficacy in the presence of microvascular disease (MVD). To overcome the limitations of FFR, the objective is to assess the recently introduced pressure drop coefficient (CDP), a fundamental fluid dynamics-based combined pressure–flow index. Methods We hypothesize that CDP will result in improved clinical outcomes in comparison to FFR. To test the hypothesis, chi-square test was performed to compare the percent major adverse cardiac events (%MACE) at 5 years between (a) FFR < 0.75 and CDP > 27.9 and (b) FFR < 0.80 and CDP > 25.4 groups using a prospective cohort study. Furthermore, Kaplan–Meier survival curves were compared between the FFR and CDP groups. The results were considered statistically significant for p < 0.05. The outcomes of the CDP arm were presumptive as clinical decision was solely based on the FFR. Results For the complete patient group, the %MACE in the CDP > 27.9 group (10 out of 35, 29%) was lower in comparison to the FFR < 0.75 group (11 out of 20, 55%), and the difference was near significant (p = 0.05). The survival analysis showed a significantly higher survival rate (p = 0.01) in the CDP > 27.9 group (n = 35) when compared to the FFR < 0.75 group (n = 20). The results remained similar for the FFR = 0.80 cutoff. The comparison of the 5-year MACE outcomes with the 1-year outcomes for the complete patient group showed similar trends, with a higher statistical significance for a longer follow-up period of 5 years. Conclusion Based on the MACE and survival analysis outcomes, CDP could possibly be an alternate diagnostic index for decision-making in the cardiac catheterization laboratory. Clinical Trial Registration www.ClinicalTrials.gov, identifier NCT01719016.
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Affiliation(s)
- Rupak K Banerjee
- Department of Mechanical and Materials Engineering, University of Cincinnati, Cincinnati, OH, United States.,Research Services, Veteran Affairs Medical Services, Cincinnati, OH, United States
| | - Sruthi Ramadurai
- Department of Mechanical and Materials Engineering, University of Cincinnati, Cincinnati, OH, United States
| | - Shreyash M Manegaonkar
- Department of Mechanical and Materials Engineering, University of Cincinnati, Cincinnati, OH, United States
| | - Marepalli B Rao
- Department of Environmental and Public Health Sciences, University of Cincinnati, Cincinnati, OH, United States
| | - Sathyaprabha Rakkimuthu
- Department of Mechanical and Materials Engineering, University of Cincinnati, Cincinnati, OH, United States
| | - Mohamed A Effat
- Department of Cardiology, University of Cincinnati Medical Center, Cincinnati, OH, United States
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Blanco PJ, Bulant CA, Ares GD, Lemos PA, Feijóo RA. A simple coronary blood flow model to study the collateral flow index. Biomech Model Mechanobiol 2021; 20:1365-1382. [PMID: 33772676 DOI: 10.1007/s10237-021-01449-1] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/12/2020] [Accepted: 03/06/2021] [Indexed: 11/25/2022]
Abstract
In this work, we present a novel modeling framework to investigate the effects of collateral circulation into the coronary blood flow physiology. A prototypical model of the coronary tree, integrated with the concept of Collateral Flow Index (CFI), is employed to gain insight about the role of model parameters associated with the collateral circuitry, which results in physically-realizable solutions for specific CFI data. Then, we discuss the mathematical feasibility of pressure-derived CFI, anatomical implications and practical considerations involving the estimation of model parameters in collateral connections. A sensitivity analysis is carried out, and the investigation of the impact of the collateral circulation on FFR values is also addressed.
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Affiliation(s)
- Pablo J Blanco
- Laboratório Nacional de Computação Científica, Av. Getúlio Vargas 333, Petrópolis, 25651-075, Brazil.
- National Institute of Science and Technology in Medicine Assisted by Scientific Computing, INCT-MACC, Petrópolis, Brazil.
| | - Carlos A Bulant
- National University of the Center and National Scientific and Technical Research Council, CONICET, Tandil, Argentina
- National Institute of Science and Technology in Medicine Assisted by Scientific Computing, INCT-MACC, Petrópolis, Brazil
| | - Gonzalo D Ares
- National University of Mar del Plata, Mar del Plata, Argentina
| | - Pedro A Lemos
- Hospital Israelita Albert Einstein., São Paulo, Brazil
- National Institute of Science and Technology in Medicine Assisted by Scientific Computing, INCT-MACC, Petrópolis, Brazil
| | - Raúl A Feijóo
- Laboratório Nacional de Computação Científica, Av. Getúlio Vargas 333, Petrópolis, 25651-075, Brazil
- National Institute of Science and Technology in Medicine Assisted by Scientific Computing, INCT-MACC, Petrópolis, Brazil
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3
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Kim YW, Moon JY, Li WJ, Kim JH, Park YH, Lee JS, Jang Y. Effect of membrane insertion for tricuspid regurgitation using immersed-boundary lattice Boltzmann method. COMPUTER METHODS AND PROGRAMS IN BIOMEDICINE 2020; 191:105421. [PMID: 32146209 DOI: 10.1016/j.cmpb.2020.105421] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/03/2019] [Revised: 02/26/2020] [Accepted: 02/27/2020] [Indexed: 06/10/2023]
Abstract
BACKGROUND Tricuspid regurgitation is treated by valve repair or replacement. However, these methods have limitations, and alternative treatment methods are therefore required. OBJECTIVES In this study, a new method of tricuspid valve treatment using artificial membrane insertion is analyzed. We performed tricuspid valve simulations using an artificial membrane inserted into the right ventricle (RV) or right atrium (RA). METHODS We use the lattice Boltzmann method with the immersed boundary condition to model the structural motion of the valve leaflet. The effect of membrane insertion is analyzed in terms of the stress, force, and impulse on the valve leaflet, along with the velocity, pressure, jet volume, and Reynolds stress in the flow field. RESULTS While the use of either membrane (RA or RV) leads to improved valve closure relative to the use of no membrane, the RV membrane is more effective than the RA membrane in achieving improved valve closure. In addition, a larger membrane area with a shorter distance between the leaflet and membrane increases membrane efficacy. CONCLUSION Our results suggest that membrane insertion can form an effective new method for the treatment of tricuspid regurgitation.
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Affiliation(s)
- Young Woo Kim
- Department of Mechanical Engineering, Yonsei University, Korea
| | | | - Wen Jie Li
- Department of Mechanical Engineering, Yonsei University, Korea
| | - June-Hong Kim
- Cardiovascular Center, Pusan National University Yangsan Hospital, Korea
| | - Yong-Hyun Park
- Cardiovascular Center, Pusan National University Yangsan Hospital, Korea
| | - Joon Sang Lee
- Department of Mechanical Engineering, Yonsei University, Korea.
| | - Yeongho Jang
- Department of Pain Medicine and Anesthesiology, Saedongsan Hospital, Korea
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4
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D'Souza GA, Taylor MD, Banerjee RK. Methodology for Hemodynamic Assessment of a Three-Dimensional Printed Patient-Specific Vascular Test Device. J Med Device 2019. [DOI: 10.1115/1.4043992] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/08/2022] Open
Abstract
Assessing hemodynamics in vasculature is important for the development of cardiovascular diagnostic parameters and evaluation of medical devices. Benchtop experiments are a safe and comprehensive preclinical method for testing new diagnostic endpoints and devices within a controlled environment. Recent advances in three-dimensional (3D) printing have enhanced benchtop tests by allowing generation of patient-specific and pathophysiologic conditions. We used 3D printing, coupled with image processing and computer-aided design (CAD), to develop a patient-specific vascular test device from clinical data. The proximal pulmonary artery (PA) tree including the main, left, and right pulmonary arteries, with a stenosis within the left PA was selected as a representative anatomy for developing the vascular test device. Three test devices representing clinically relevant stenosis severities, 90%, 80%, and 70% area stenosis, were evaluated at different cardiac outputs (COs). A mock circulatory loop (MCL) generating pathophysiologic pulmonary pressure and flow was used to evaluate the hemodynamics within the devices. The dimensionless pressure drop–velocity ratio characteristic curves for the three stenosis severities were obtained. At a fixed CO, the dimensionless pressure drop increased nonlinearly with an increase in (a) the velocity ratio for a fixed stenosis severity and (b) the stenosis severity at a specific velocity ratio. The dimensionless pressure drop observed in vivo was similar (within 1%) to that measured in moderate area stenosis of 70% because both flows were viscous dominated. The hemodynamics of the 3D printed test device can be used for evaluating diagnostic endpoints and medical devices in a preclinical setting under realistic conditions.
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Affiliation(s)
- Gavin A. D'Souza
- Department of Mechanical and Materials Engineering, University of Cincinnati, Cincinnati, OH 45221
| | - Michael D. Taylor
- The Heart Institute, Cincinnati Children's Hospital Medical Center, Cincinnati, OH 45229
| | - Rupak K. Banerjee
- Department of Mechanical and Materials Engineering, University of Cincinnati, 593 Rhodes Hall, Cincinnati, OH 45221 e-mail:
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5
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Coppel R, Lagache M, Finet G, Rioufol G, Gómez A, Dérimay F, Malvé M, Yazdani SK, Pettigrew RI, Ohayon J. Influence of Collaterals on True FFR Prediction for a Left Main Stenosis with Concomitant Lesions: An In Vitro Study. Ann Biomed Eng 2019; 47:1409-1421. [DOI: 10.1007/s10439-019-02235-y] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/02/2018] [Accepted: 02/20/2019] [Indexed: 12/20/2022]
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D'Souza GA, Banerjee RK, Taylor MD. Evaluation of pulmonary artery stenosis in congenital heart disease patients using functional diagnostic parameters: An in vitro study. J Biomech 2018; 81:58-67. [PMID: 30293825 DOI: 10.1016/j.jbiomech.2018.09.014] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/21/2018] [Revised: 07/23/2018] [Accepted: 09/13/2018] [Indexed: 02/03/2023]
Abstract
Congenital pulmonary artery (PA) stenosis is often associated with abnormal PA hemodynamics including increased pressure drop (Δp) and reduced asymmetric flow (Q), which may result in right ventricular dysfunction. We propose functional diagnostic parameters, pressure drop coefficient (CDP), energy loss (Eloss), and normalized energy loss (E¯loss) to characterize pulmonary hemodynamics, and evaluate their efficacy in delineating stenosis severity using in vitro experiments. Subject-specific test sections including the main PA (MPA) bifurcating into left and right PAs (LPA, RPA) with a discrete LPA stenosis were manufactured from cross-sectional imaging and 3D printing. Three clinically-relevant stenosis severities, 90% area stenosis (AS), 80% AS, and 70% AS, were evaluated at different cardiac outputs (COs). A benchtop flow loop simulating pulmonary hemodynamics was used to measure Q and Δp within the test sections. The experimental Δp-Q characteristics along with clinical data were used to obtain pathophysiologic conditions and compute the diagnostic parameters. The pathophysiologic QLPA decreased as the stenosis severity increased at a fixed CO. CDPLPA, Eloss,LPA (absolute), and E¯loss,LPA (absolute) increased with an increase in LPA stenosis severity at a fixed CO. Importantly, CDPLPA and E¯loss,LPA had reduced variability with CO, and distinct values for each LPA stenosis severity. Under variable CO, a) CDPLPA values were 14.5-21.0 (70% AS), 60.7- 2.2 (80% AS), ≥ 261.6 (90% AS), and b) E¯loss,LPA values (in mJ per QLPA) were -501.9 to -1023.8 (70% AS), -1247.6 to -1773.0 (80% AS), -1934.5 (90% AS). Hence, CDPLPA and E¯loss,LPA are expected to assess the true functional severity of PA stenosis.
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Affiliation(s)
- Gavin A D'Souza
- Department of Mechanical and Materials Engineering, University of Cincinnati, Cincinnati, OH, USA
| | - Rupak K Banerjee
- Department of Mechanical and Materials Engineering, University of Cincinnati, Cincinnati, OH, USA.
| | - Michael D Taylor
- The Heart Institute, Cincinnati Children's Hospital Medical Center, Cincinnati, OH, USA.
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Ahamad NA, Kamangar S, Badruddin IA. The influence of curvature wall on the blood flow in stenosed artery: A computational study. Biomed Mater Eng 2018; 29:319-332. [DOI: 10.3233/bme-181734] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/15/2022]
Affiliation(s)
- N. Ameer Ahamad
- Mathematics Department, Faculty of Science, University of Tabuk, Saudi Arabia
| | - Sarfaraz Kamangar
- Department of Mechanical Engineering, University of Malaya, Kuala Lumpur, Malaysia
| | - Irfan Anjum Badruddin
- Department of Mechanical Engineering, College of Engineering, King Khalid University, Abha, 61421, Saudi Arabia
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8
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Hebbar UU, Effat MA, Peelukhana SV, Arif I, Banerjee RK. Delineation of epicardial stenosis in patients with microvascular disease using pressure drop coefficient: A pilot outcome study. World J Cardiol 2017; 9:813-821. [PMID: 29317987 PMCID: PMC5746623 DOI: 10.4330/wjc.v9.i12.813] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 07/26/2017] [Revised: 09/18/2017] [Accepted: 10/29/2017] [Indexed: 02/07/2023] Open
Abstract
AIM To investigate the patient-outcomes of newly developed pressure drop coefficient (CDP) in diagnosing epicardial stenosis (ES) in the presence of concomitant microvascular disease (MVD).
METHODS Patients from our clinical trial were divided into two subgroups with: (1) cut-off of coronary flow reserve (CFR) < 2.0; and (2) diabetes. First, correlations were performed for both subgroups between CDP and hyperemic microvascular resistance (HMR), a diagnostic parameter for assessing the severity of MVD. Linear regression analysis was used for these correlations. Further, in each of the subgroups, comparisons were made between fractional flow reserve (FFR) < 0.75 and CDP > 27.9 groups for assessing major adverse cardiac events (MACE: Primary outcome). Comparisons were also made between the survival curves for FFR < 0.75 and CDP > 27.9 groups. Two tailed chi-squared and Fischer’s exact tests were performed for comparison of the primary outcomes, and the log-rank test was used to compare the Kaplan-Meier survival curves. P < 0.05 for all tests was considered statistically significant.
RESULTS Significant linear correlations were observed between CDP and HMR for both CFR < 2.0 (r = 0.58, P < 0.001) and diabetic (r = 0.61, P < 0.001) patients. In the CFR < 2.0 subgroup, the %MACE (primary outcomes) for CDP > 27.9 group (7.7%, 2/26) was lower than FFR < 0.75 group (3/14, 21.4%); P = 0.21. Similarly, in the diabetic subgroup, the %MACE for CDP > 27.9 group (12.5%, 2/16) was lower than FFR < 0.75 group (18.2%, 2/11); P = 0.69. Survival analysis for CFR < 2.0 subgroup indicated better event-free survival for CDP > 27.9 group (n = 26) when compared with FFR < 0.75 group (n = 14); P = 0.10. Similarly, for the diabetic subgroup, CDP > 27.9 group (n = 16) showed higher survival times compared to FFR group (n = 11); P = 0.58.
CONCLUSION CDP correlated significantly with HMR and resulted in better %MACE as well as survival rates in comparison to FFR. These positive trends demonstrate that CDP could be a potential diagnostic endpoint for delineating MVD with or without ES.
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Affiliation(s)
- Ullhas Udaya Hebbar
- Department of Mechanical and Materials Engineering, University of Cincinnati, Cincinnati, OH 45221, United States
| | - Mohamed A Effat
- Division of Cardiovascular Diseases, University of Cincinnati Medical Center, Veteran Affairs Medical Center, Cincinnati, OH 45221, United States
| | - Srikara V Peelukhana
- Department of Mechanical and Materials Engineering, University of Cincinnati, Veteran Affairs Medical Center, Cincinnati, OH 45221, United States
| | - Imran Arif
- Division of Cardiovascular Diseases, University of Cincinnati Medical Center, Veteran Affairs Medical Center, Cincinnati, OH 45221, United States
| | - Rupak K Banerjee
- Department of Mechanical and Materials Engineering, Veteran Affairs Medical Center, Cincinnati, OH 45221, United States
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GOVINDARAJU KALIMUTHU, VISWANATHAN GIRISHN, BADRUDDIN IRFANANJUM, WELDEMARIAM SIRAKAREGAWI, GEBREHIWOT WOLDUZINA, KAMANGAR SARFARAZ. THE MECHANICAL FACTORS INFLUENCING THE ASSESSMENT OF INTERMEDIATE STENOSIS SEVERITY EXPLAINED THROUGH FRACTIONAL FLOW RESERVE. J MECH MED BIOL 2017. [DOI: 10.1142/s0219519417300010] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/10/2023]
Abstract
Assessment of intermediate coronary lesions with diameter stenosis of 40% to 70% severity is being a challenge for cardiologist to identify potentially ischemic stenosis for revascularization and nonculprit stenosis which can be deferred from stenting. An invasive coronary angiography and intravascular ultrasound provide anatomic information of stenosis severity whereas an invasive fractional flow reserve index (FFR) provides the functional significance of the stenosis severity. The measurement of functional significance of stenosis severity minimizes the procedural complications such as coronary dissection, in stent restenosis etc. rather than anatomical significance measure. The FFR cutoff value of [Formula: see text]0.8 is used to distinguish ischemic and nonischemic stenosis. The FFR is clinically well validated even though it is influenced by the mechanical factors such as hyperemic flow and guide wire insertion. In recent times, noninvasive coronary computed tomography (CCTA) modality has become popular in the diagnosis of coronary artery disease. The CCTA permits the assessment of cross-sectional parameters such as minimum lumen area and lumen diameter, lesion length and plaque morphology. However, the CCTA provides limited information on the functional significance of stenotic lesions as compared to FFR. The purpose of this review is to discuss the mechanical factors influencing the invasive FFR while assessing the functional significance of intermediate stenosis severity. In addition, the hidden mechanical factors influencing the noninvasive CCTA assessment of stenosis severity will be discussed from the critical information obtained from FFR which could be beneficial for the clinician particularly in the assessment of intermediate stenosis severity.
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Affiliation(s)
- KALIMUTHU GOVINDARAJU
- Ethiopian Institute of Technology, School of Mechanical and Industrial Engineering, Mekelle University, Mekelle, Ethiopia
| | | | | | - SIRAK AREGAWI WELDEMARIAM
- Ethiopian Institute of Technology, School of Mechanical and Industrial Engineering, Mekelle University, Mekelle, Ethiopia
| | - WOLDU ZINA GEBREHIWOT
- Ethiopian Institute of Technology, School of Mechanical and Industrial Engineering, Mekelle University, Mekelle, Ethiopia
| | - SARFARAZ KAMANGAR
- Department of Mechanical Engineering, University of Malaya, Malaysia
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Kamangar S, Badruddin IA, Ameer Ahamad N, Soudagar MEM, Govindaraju K, Nik-Ghazali N, Salman Ahmed N, Yunus Khan T. Patient specific 3-d modeling of blood flow in a multi-stenosed left coronary artery. Biomed Mater Eng 2017; 28:257-266. [DOI: 10.3233/bme-171672] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/13/2023]
Affiliation(s)
- Sarfaraz Kamangar
- Department of Mechanical Engineering, University of Malaya, Kuala Lumpur 50603, Malaysia
| | - Irfan Anjum Badruddin
- Department of Mechanical Engineering, University of Malaya, Kuala Lumpur 50603, Malaysia
| | - N. Ameer Ahamad
- Mathematics Department, Faculty of Science, University of Tabuk, Saudi Arabia
| | | | - Kalimuthu Govindaraju
- Department of Mechanical and Industrial Engineering, Mekelle University, Mekelle, Ethiopia
| | - N. Nik-Ghazali
- Department of Mechanical Engineering, University of Malaya, Kuala Lumpur 50603, Malaysia
| | - N.J. Salman Ahmed
- Department of Mechanical and Industrial Engineering, Sultan Qaboos University, Al Khoud, Muscat, 123, Oman
| | - T.M. Yunus Khan
- Department of Mechanical Engineering, University of Malaya, Kuala Lumpur 50603, Malaysia
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Kamangar S, Badruddin IA, Govindaraju K, Nik-Ghazali N, Badarudin A, Viswanathan GN, Ahmed NJS, Khan TMY. Patient-specific 3D hemodynamics modelling of left coronary artery under hyperemic conditions. Med Biol Eng Comput 2016; 55:1451-1461. [DOI: 10.1007/s11517-016-1604-8] [Citation(s) in RCA: 16] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/05/2016] [Accepted: 12/01/2016] [Indexed: 11/29/2022]
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12
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Kamangar S, Badruddin IA, Badarudin A, Nik-Ghazali N, Govindaraju K, Salman Ahmed NJ, Yunus Khan TM. Influence of stenosis on hemodynamic parameters in the realistic left coronary artery under hyperemic conditions. Comput Methods Biomech Biomed Engin 2016; 20:365-372. [DOI: 10.1080/10255842.2016.1233402] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/21/2022]
Affiliation(s)
- Sarfaraz Kamangar
- Department of Mechanical Engineering, University of Malaya, Kuala Lumpur, 50603, Malaysia
| | - Irfan Anjum Badruddin
- Department of Mechanical Engineering, University of Malaya, Kuala Lumpur, 50603, Malaysia
| | - A. Badarudin
- Department of Mechanical Engineering, University of Malaya, Kuala Lumpur, 50603, Malaysia
| | - N. Nik-Ghazali
- Department of Mechanical Engineering, University of Malaya, Kuala Lumpur, 50603, Malaysia
| | - Kalimuthu Govindaraju
- Department of Mechanical Engineering, University of Malaya, Kuala Lumpur, 50603, Malaysia
| | - N. J. Salman Ahmed
- Center for Energy Sciences, Department of Mechanical Engineering, University of Malaya, Kuala Lumpur, 50603, Malaysia
| | - T. M. Yunus Khan
- Department of Mechanical Engineering, University of Malaya, Kuala Lumpur, 50603, Malaysia
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13
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Effat MA, Peelukhana SV, Banerjee RK. Clinical outcomes of combined flow-pressure drop measurements using newly developed diagnostic endpoint: Pressure drop coefficient in patients with coronary artery dysfunction. World J Cardiol 2016; 8:283-292. [PMID: 27022460 PMCID: PMC4807317 DOI: 10.4330/wjc.v8.i3.283] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 07/31/2015] [Revised: 11/02/2015] [Accepted: 01/04/2016] [Indexed: 02/06/2023] Open
Abstract
AIM: To combine pressure and flow parameter, pressure drop coefficient (CDP) will result in better clinical outcomes in comparison to the fractional flow reserve (FFR) group.
METHODS: To test this hypothesis, a comparison was made between the FFR < 0.75 and CDP > 27.9 groups in this study, for the major adverse cardiac events [major adverse cardiac events (MACE): Primary outcome] and patients’ quality of life (secondary outcome). Further, a comparison was also made between the survival curves for the FFR < 0.75 and CDP > 27.9 groups. Two-tailed χ2 test proportions were performed for the comparison of primary and secondary outcomes. Kaplan-Meier survival analysis was performed to compare the survival curves of FFR < 0.75 and CDP > 27.9 groups (MedcalcV10.2, Mariakerke, Belgium). Results were considered statistically significant for P < 0.05.
RESULTS: The primary outcomes (%MACE) in the FFR < 0.75 group (20%, 4 out of 20) was not statistically different (P = 0.24) from the %MACE occurring in CDP > 27.9 group (8.57%, 2 out of 35). Noteworthy is the reduction in the %MACE in the CDP > 27.9 group, in comparison to the FFR < 0.75 group. Further, the secondary outcomes were not statistically significant between the FFR < 0.75 and CDP > 27.9 groups. Survival analysis results suggest that the survival time for the CDP > 27.9 group (n = 35) is significantly higher (P = 0.048) in comparison to the survival time for the FFR < 0.75 group (n = 20). The results remained similar for a FFR = 0.80 cut-off.
CONCLUSION: Based on the above, CDP could prove to be a better diagnostic end-point for clinical revascularization decision-making in the cardiac catheterization laboratories.
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14
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Kolli KK, van de Hoef TP, Effat MA, Banerjee RK, Peelukhana SV, Succop P, Leesar MA, Imran A, Piek JJ, Helmy TA. Diagnostic cutoff for pressure drop coefficient in relation to fractional flow reserve and coronary flow reserve: A patient-level analysis. Catheter Cardiovasc Interv 2015; 87:273-82. [PMID: 26424295 DOI: 10.1002/ccd.26063] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 11/21/2014] [Revised: 03/31/2015] [Accepted: 05/19/2015] [Indexed: 12/28/2022]
Abstract
OBJECTIVES AND BACKGROUND Functional assessment of intermediate coronary stenosis during cardiac catheterization is conducted using diagnostic parameters like fractional flow reserve (FFR), coronary flow reserve (CFR), hyperemic stenosis resistance index (HSR), and hyperemic microvascular resistance (HMR). CDP (ratio of pressure drop across a stenosis to distal dynamic pressure), a nondimensional index derived from fundamental fluid dynamic principles, based on a combination of intracoronary pressure, and flow measurements may improve the functional assessment of coronary lesion severity. METHODS Patient-level data pertaining to 350 intracoronary pressure and flow measurements across coronary stenoses was assessed to evaluate CFR, FFR, HSR, HMR, and CDP. CDP was calculated as (ΔP)/(0.5 × ρ × APV(2)). The density of blood (ρ) was assumed to be 1.05 g/cm(3). The correlation of current diagnostic parameters (CFR, FFR, HSR, and HMR) with CDP was evaluated. The receiver operating characteristic (ROC) curve was used to identify the optimal cut-off point of CDP, corresponding to the clinically used cut-off values (FFR = 0.80 and CFR = 2.0). RESULTS CDP correlated significantly with FFR (r = 0.81, P < 0.05) and had significant diagnostic efficiency (ROC-area under curve of 86%), specificity (72%) and sensitivity (85%) at FFR < 0.8. The corresponding cut-off value for CDP to detect FFR < 0.8 was at CDP>25.4. CDP also correlated significantly (r = 0.98, P < 0.05) with epicardial-specific parameter, HSR. CONCLUSIONS CDP, a functional parameter based on both intracoronary pressure and flow measurements, has close agreement (area under ROC curve = 86%) with FFR, the frequently used method of evaluating stenosis severity.
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Affiliation(s)
- Kranthi K Kolli
- Department of Mechanical and Materials Engineering, University of Cincinnati, Cincinnati, Ohio.,Veteran Affairs Medical Center, Cincinnati, Ohio
| | - Tim P van de Hoef
- Department of Cardiology, Academic Medical Center, Amsterdam, The Netherlands
| | - Mohamed A Effat
- Veteran Affairs Medical Center, Cincinnati, Ohio.,Division of Cardiovascular Disease, University of Cincinnati, Cincinnati, Ohio
| | - Rupak K Banerjee
- Department of Mechanical and Materials Engineering, University of Cincinnati, Cincinnati, Ohio.,Veteran Affairs Medical Center, Cincinnati, Ohio
| | - Srikara V Peelukhana
- Department of Mechanical and Materials Engineering, University of Cincinnati, Cincinnati, Ohio.,Veteran Affairs Medical Center, Cincinnati, Ohio
| | - Paul Succop
- Department of Environmental Health, University of Cincinnati, Cincinnati, Ohio
| | - Massoud A Leesar
- Division of Cardiovascular Disease, University of Alabama-Birmingham, Alabama
| | - Arif Imran
- Veteran Affairs Medical Center, Cincinnati, Ohio.,Division of Cardiovascular Disease, University of Cincinnati, Cincinnati, Ohio
| | - Jan J Piek
- Department of Cardiology, Academic Medical Center, Amsterdam, The Netherlands
| | - Tarek A Helmy
- Division of Cardiology, Saint Louis University School of Medicine, St. Louis, Missouri
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Rajabi-Jaghargh E, Banerjee RK. Combined functional and anatomical diagnostic endpoints for assessing arteriovenous fistula dysfunction. World J Nephrol 2015; 4:6-18. [PMID: 25664243 PMCID: PMC4317629 DOI: 10.5527/wjn.v4.i1.6] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 07/19/2014] [Revised: 08/26/2014] [Accepted: 11/19/2014] [Indexed: 02/06/2023] Open
Abstract
Failure of arteriovenous fistulas (AVF) to mature and thrombosis in matured fistulas have been the major causes of morbidity and mortality in hemodialysis patients. Stenosis, which occurs due to adverse remodeling in AVFs, is one of the major underlying factors under both scenarios. Early diagnosis of a stenosis in an AVF can provide an opportunity to intervene in a timely manner for either assisting the maturation process or avoiding the thrombosis. The goal of surveillance strategies was to supplement the clinical evaluation (i.e., physical examination) of the AVF for better and earlier diagnosis of a developing stenosis. Surveillance strategies were mainly based on measurement of functional hemodynamic endpoints, including blood flow (Qa) to the vascular access and venous access pressure (VAP). As the changes in arterial pressure (MAP) affects the level of VAP, the ratio of VAP to MAP (VAPR = VAP/MAP) was used for diagnosis. A Qa < 400-500 mL/min or a VAPR > 0.55 is considered sign of significant stenosis, which requires immediate intervention. However, due to the complex nature of AVFs, the surveillance strategies have failed to consistently detect stenosis under different scenarios. VAPR has been primarily developed to detect outflow stenosis in arteriovenous grafts, and it hasn’t been successful in accurate diagnosis of outflow lesions in AVFs. Similarly, AVFs can maintain relatively high blood flow despite the presence of a significant outflow stenosis and thus, Qa has been found to be a better predictor of only inflow lesions. Similar shortcomings have been reported in the detection of functional severity of coronary stenosis using diagnostic endpoints that were based on either flow or pressure. This limitation has been associated with the fact that both pressure and flow change in the presence of a stenosis and thus, hemodynamic diagnostic endpoints that employ only one of these parameters are inherently prone to inaccuracies. Recent attempts have resulted in development of new diagnostic endpoints that can combine the effects of pressure and flow. These new hemodynamic diagnostic endpoints have shown to be better predictors of functional severity of lesions as compared to either flow or pressure based counterparts. In this review article, we discussed the advantages and limitations of current functional and anatomical diagnostic endpoints in AVFs.
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Numerical investigation of the effect of stenosis geometry on the coronary diagnostic parameters. ScientificWorldJournal 2014; 2014:354946. [PMID: 25258722 PMCID: PMC4167444 DOI: 10.1155/2014/354946] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/08/2014] [Accepted: 07/20/2014] [Indexed: 01/07/2023] Open
Abstract
The present study deals with the functional severity of a coronary artery stenosis assessed by the fractional flow reserve (FFR). The effects of different geometrical shapes of lesion on the diagnostic parameters are unknown. In this study, 3D computational simulation of blood flow in three different geometrical shapes of stenosis (triangular, elliptical, and trapezium) is considered in steady and transient conditions for 70% (moderate), 80% (intermediate), and 90% (severe) area stenosis (AS). For a given percentage AS, the variation of diagnostic parameters which are derived from pressure drop across the stenosis was found in three different geometrical shapes of stenosis and it was observed that FFR is higher in triangular shape and lower in trapezium shape. The pressure drop coefficient (CDP) was higher in trapezium shape and lower in triangular model whereas the LFC shows opposite trend. From the clinical perspective, the relationship between percentage AS and FFR is linear and inversely related in all the three models. A cut-off value of 0.75 for FFR was observed at 76.5% AS in trapezium model, 79.5% in elliptical model, and 82.7% AS for the triangular shaped model. The misinterpretation of the functional severity of the stenosis is in the region of 76.5%-82.7 % AS from different shapes of stenosis models.
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Peelukhana SV, Kerr H, Kolli KK, Fernandez-Ulloa M, Gerson M, Effat M, Arif I, Helmy T, Banerjee R. Benefit of cardiac N-13 PET CFR for combined anatomical and functional diagnosis of ischemic coronary artery disease: a pilot study. Ann Nucl Med 2014; 28:746-60. [DOI: 10.1007/s12149-014-0869-y] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/25/2014] [Accepted: 06/05/2014] [Indexed: 01/26/2023]
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Kolli KK, Effat MA, Peelukhana SV, Succop P, Back LH, Leesar MA, Helmy TA, Imran A, Banerjee RK. Hyperemia-free delineation of epicardial and microvascular impairments using a basal index. Ann Biomed Eng 2014; 42:1681-90. [PMID: 24806315 DOI: 10.1007/s10439-014-1020-x] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/01/2014] [Accepted: 04/26/2014] [Indexed: 01/18/2023]
Abstract
The assessment of functional coronary lesion severity using intracoronary hemodynamic parameters like the pressure-derived fractional flow reserve and the flow-derived coronary flow reserve are known to rely critically on the establishment of maximal hyperemia. We evaluated a hyperemia-free index, basal pressure drop coefficient (bCDP), that combines pressure and velocity for simultaneous assessment of the status of both epicardial and microvascular circulations. In 23 pigs, simultaneous measurements of distal coronary arterial pressure and flow were performed using a dual-sensor tipped guidewire in the settings of both normal and abnormal microcirculation with the presence of epicardial lesions of area stenosis (AS) < 50% and AS > 50%. The bCDP, a parameter based on fundamental fluid dynamics principles, was calculated as the transtenotic pressure-drop divided by the dynamic pressure in the distal vessel, measured under baseline (without hyperemia) conditions. The group mean values of bCDP for normal (84 ± 18) and abnormal (124.5 ± 15.6) microcirculation were significantly different. Similarly, the mean values of bCDP from AS < 50% (72.5 ± 16.1) and AS > 50% (136 ± 17.2) were also significantly different (p < 0.05). The bCDP could significantly distinguish between lesions of AS < 50% to AS > 50% under normal microcirculation (52.1 vs. 85.8; p < 0.05) and abnormal microcirculation (84.9 vs. 172; p < 0.05). Further, the bCDP correlated linearly and significantly with the hyperemic parameters FFR (r = 0.42, p < 0.05) and CDP (r = 0.50, p < 0.05). The bCDP is a promising clinical diagnostic parameter that can independently assess the severity of epicardial stenosis and microvascular impairment. We believe that it has an immediate appeal for detection of coronary artery disease if validated clinically.
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Affiliation(s)
- Kranthi K Kolli
- Department of Mechanical and Materials Engineering, University of Cincinnati, 598 Rhodes Hall, PO Box 210072, Cincinnati, OH, 45221-0072, USA
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Govindaraju K, Kamangar S, Badruddin IA, Viswanathan GN, Badarudin A, Salman Ahmed N. Effect of porous media of the stenosed artery wall to the coronary physiological diagnostic parameter: A computational fluid dynamic analysis. Atherosclerosis 2014; 233:630-635. [DOI: 10.1016/j.atherosclerosis.2014.01.043] [Citation(s) in RCA: 22] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 10/11/2013] [Revised: 01/05/2014] [Accepted: 01/20/2014] [Indexed: 11/28/2022]
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D’Souza GA, Peelukhana SV, Banerjee RK. Diagnostic Uncertainties During Assessment of Serial Coronary Stenoses: An In Vitro Study. J Biomech Eng 2014; 136:021026. [DOI: 10.1115/1.4026317] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/22/2013] [Accepted: 12/23/2013] [Indexed: 02/02/2023]
Abstract
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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Affiliation(s)
- Gavin A. D’Souza
- School of Dynamic Systems, Mechanical Engineering Program, University of Cincinnati, Cincinnati, OH 45221
| | - Srikara V. Peelukhana
- School of Dynamic Systems, Mechanical Engineering Program, University of Cincinnati, Cincinnati, OH 45221
| | - Rupak K. Banerjee
- School of Dynamic Systems, Mechanical Engineering Program, University of Cincinnati, Cincinnati, OH 45221 e-mail:
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Kolli KK, Helmy TA, Peelukhana SV, Arif I, Leesar MA, Back LH, Banerjee RK, Effat MA. Functional diagnosis of coronary stenoses using pressure drop coefficient: a pilot study in humans. Catheter Cardiovasc Interv 2013; 83:377-85. [PMID: 23785016 DOI: 10.1002/ccd.25085] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 09/16/2012] [Revised: 04/27/2013] [Accepted: 06/09/2013] [Indexed: 01/10/2023]
Abstract
OBJECTIVES AND BACKGROUND Myocardial fractional flow reserve (FFR) in conjunction with coronary flow reserve (CFR) is used to evaluate the hemodynamic severity of coronary lesions. However, discordant results between FFR and CFR have been observed in intermediate coronary lesions. A functional parameter, pressure drop coefficient (CDP; ratio of pressure drop to distal dynamic pressure), was assessed using intracoronary pressure drop (dp) and average peak velocity (APV). The CDP is a nondimensional ratio, derived from fundamental fluid dynamic principles. We sought to evaluate the correlation of CDP with FFR, CFR, and hyperemic stenosis resistance (HSR: ratio of pressure drop to APV) in human subjects. METHODS Twenty-seven patients with reversible perfusion defects based on SPECT were consented for the study before cardiac catheterization. Distal coronary pressure and APV were measured simultaneously for each coronary lesion using a Combowire(©) during cardiac catheterization. Reference diameter, minimal lumen diameter, and %AS were obtained by quantitative coronary angiography. Maximum hyperemia was induced by IV adenosine (140 µg/kg/min). CDP was calculated as, (Δp)/(0.5 × ρ × APV(2) ). The density of blood (ρ) was assumed to be 1.05 gm/cm(3) . RESULTS The functional index, CDP, when correlated simultaneously with FFR and CFR, was found to have a significant correlation (r = 0.61; P < 0.05). Similarly a significant correlation was achieved when CDP was correlated with HSR (r = 0.91; P < 0.001). This is consistent with the definition of CDP, which is a functional parameter that includes both pressure and flow information. CONCLUSIONS 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.
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Affiliation(s)
- Kranthi K Kolli
- School of Dynamic Systems, Mechanical Engineering Program, University of Cincinnati, Cincinnati, Ohio; Veteran Affairs Medical Center, Cincinnati, Ohio
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Goswami I, Peelukhana SV, Al-Rjoub MF, Back LH, Banerjee RK. Influence of Variable Native Arterial Diameter and Vasculature Status on Coronary Diagnostic Parameters. J Biomech Eng 2013; 135:91005. [DOI: 10.1115/1.4024682] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/13/2012] [Accepted: 05/31/2013] [Indexed: 12/26/2022]
Abstract
In current practice, diagnostic parameters, such as fractional flow reserve (FFR) and coronary flow reserve (CFR), are used to determine the severity of a coronary artery stenosis. FFR is defined as the ratio of hyperemic pressures distal (p˜rh) and proximal (p˜ah) to a stenosis. CFR is the ratio of flow at hyperemic and basal condition. Another diagnostic parameter suggested by our group is the pressure drop coefficient (CDP). CDP is defined as the ratio of the pressure drop across the stenosis to the upstream dynamic pressure. These parameters are evaluated by invasively measuring flow (CFR), pressure (FFR), or both (CDP) in a diseased artery using guidewire tipped with a sensor. Pathologic state of artery is indicated by lower CFR (<2). Similarly, FFR lower than 0.75 leads to clinical intervention. Cutoff for CDP is under investigation. Diameter and vascular condition influence both flow and pressure drop, and thus, their effect on FFR and CDP was studied. In vitro experiment coupled with pressure-flow relationships from human clinical data was used to simulate pathophysiologic conditions in two representative arterial diameters, 2.5 mm (N1) and 3 mm (N2). With a 0.014 in. (0.35 mm) guidewire inserted, diagnostic parameters were evaluated for mild (∼64% area stenosis (AS)), intermediate (∼80% AS), and severe (∼90% AS) stenosis for both N1 and N2 arteries, and between two conditions, with and without myocardial infarction (MI). Arterial diameter did not influence FFR for clinically relevant cases of mild and intermediate stenosis (difference < 5%). Stenosis severity was underestimated due to higher FFR (mild: ∼9%, intermediate: ∼ 20%, severe: ∼ 30%) for MI condition because of lower pressure drops, and this may affect clinical decision making. CDP varied with diameter (mild: ∼20%, intermediate: ∼24%, severe: by 2.5 times), and vascular condition (mild: ∼35%, intermediate: ∼14%, severe: ∼ 9%). However, nonoverlapping range of CDP allowed better delineation of stenosis severities irrespective of diameter and vascular condition.
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Affiliation(s)
| | | | - Marwan F. Al-Rjoub
- School of Dynamic Systems, Mechanical Engineering Program, University of Cincinnati, Cincinnati, OH 45221
| | - Lloyd H. Back
- Jet Propulsion Laboratory, California Institute of Technology, Pasadena, CA 91125
| | - Rupak K. Banerjee
- School of Dynamic Systems, Mechanical Engineering Program, University of Cincinnati, Cincinnati, OH 45221 e-mail:
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Wasilewski J, Mirota K, Hawranek M, Poloński L. Invasive and non-invasive fractional flow reserve index in validation of hemodynamic severity of intracoronary lesions. ADVANCES IN INTERVENTIONAL CARDIOLOGY 2013; 9:160-9. [PMID: 24570710 PMCID: PMC3915971 DOI: 10.5114/pwki.2013.35452] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/25/2012] [Revised: 03/25/2013] [Accepted: 04/22/2013] [Indexed: 01/17/2023] Open
Abstract
This review discusses visual and functional evaluation of the hemodynamic significance of the degree of stenosis in coronary angiography, with respect to the indications for revascularization. The concept of the coronary flow reserve is defined, and the theoretical assumptions of the invasive measurement of the fractional flow reserve (FFR) are presented. In the following part, the publication describes the basic steps of numerical stimulations in terms of computational fluid dynamics (CFD) in calculating the fractional flow reserve based on computed tomography (CT) coronary angiography (FFRCT). The numerical FFRCT estimation in correlation with invasive measurements, as well as benefits deriving from FFRCT in the diagnosis of coronary artery disease, is presented in the example of the multicentre prospective DISCOVER-FLOW trial and the DeFACTO project. The CDF method enables to obtain hemodynamic significance of stenosis solely from the coronary anatomy vizualized by CT angiography. The calculation of FFRCT increases the diagnostic reliability of coronary flow reserve estimations. It contributes to the improvement in patients' qualification for contrast coronarography. If the accuracy of FFRCT is confirmed in clinical practice, and the time required for computational processing is shortened, it may turn out that the algorithms of coronary heart disease diagnosis will be verified and it will be to a greater extent based on the CT results.
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Affiliation(s)
- Jarosław Wasilewski
- 3 Department of Cardiology, Silesian Center for Heart Diseases, Medical University of Silesia, Zabrze, Poland
| | | | - Michał Hawranek
- 3 Department of Cardiology, Silesian Center for Heart Diseases, Medical University of Silesia, Zabrze, Poland
| | - Lech Poloński
- 3 Department of Cardiology, Silesian Center for Heart Diseases, Medical University of Silesia, Zabrze, Poland
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Peelukhana SV, Kolli KK, Leesar MA, Effat MA, Helmy TA, Arif I, Schneeberger EW, Succop P, Banerjee RK. Effect of myocardial contractility on hemodynamic end points under concomitant microvascular disease in a porcine model. Heart Vessels 2013; 29:97-109. [PMID: 23624760 DOI: 10.1007/s00380-013-0355-9] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 10/23/2012] [Accepted: 04/12/2013] [Indexed: 12/15/2022]
Abstract
In this study, coronary diagnostic parameters, pressure drop coefficient (CDP: ratio of trans-stenotic pressure drop to distal dynamic pressure), and lesion flow coefficient (LFC: ratio of % area stenosis (%AS) to the CDP at throat region), were evaluated to distinguish levels of %AS under varying contractility conditions, in the presence of microvascular disease (MVD). In 10 pigs, %AS and MVD were created using angioplasty balloons and 90-μm microspheres, respectively. Simultaneous measurements of pressure drop, left ventricular pressure (p), and velocity were obtained. Contractility was calculated as (dp/dt)max, categorized into low contractility <900 mmHg/s and high contractility >900 mmHg/s, and in each group, compared between %AS <50 and >50 using analysis of variance. In the presence of MVD, between the %AS <50 and >50 groups, values of CDP (71 ± 1.4 and 121 ± 1.3) and LFC (0.10 ± 0.04 and 0.19 ± 0.04) were significantly different (P < 0.05), under low-contractility conditions. A similar %AS trend was observed under high-contractility conditions (CDP: 18 ± 1.4 and 91 ± 1.4; LFC: 0.08 ± 0.04 and 0.25 ± 0.04). Under MVD conditions, similar to fractional flow reserve, CDP and LFC were not influenced by contractility.
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Affiliation(s)
- Srikara Viswanath Peelukhana
- School of Dynamic Systems, Department of Mechanical Engineering, University of Cincinnati, 593 Rhodes Hall, Cincinnati, OH, 45220, USA
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Zhang Z, Takarada S, Molloi S. Quantification of absolute coronary flow reserve and relative fractional flow reserve in a swine animal model using angiographic image data. Am J Physiol Heart Circ Physiol 2012; 303:H401-10. [PMID: 22661513 DOI: 10.1152/ajpheart.00153.2012] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 01/17/2023]
Abstract
Coronary flow reserve (CFR) and fractional flow reserve (FFR) are important physiological indexes for coronary disease. The purpose of this study was to validate the CFR and FFR measurement techniques using only angiographic image data. Fifteen swine were instrumented with an ultrasound flow probe on the left anterior descending artery (LAD). Microspheres were gradually injected into the LAD to create microvascular disruption. An occluder was used to produce stenosis. Contrast material injections were made into the left coronary artery during image acquisition. Volumetric blood flow from the flow probe (Q(q)) was continuously recorded. Angiography-based blood flow (Q(a)) was calculated by using a time-density curve based on the first-pass analysis technique. Flow probe-based CFR (CFR(q)) and angiography-based CFR (CFR(a)) were calculated as the ratio of hyperemic to baseline flow using Q(q) and Q(a), respectively. Relative angiographic FFR (relative FFR(a)) was calculated as the ratio of the normalized Q(a) in LAD to the left circumflex artery (LC(X)) during hyperemia. Flow probe-based FFR (FFR(q)) was measured from the ratio of hyperemic flow with and without disease. CFR(a) showed a strong correlation with the gold standard CFR(q) (CFR(a) = 0.91 CFR(q) + 0.30; r = 0.90; P < 0.0001). Relative FFR(a) correlated linearly with FFR(q) (relative FFR(a) = 0.86 FFR(q) + 0.05; r = 0.90; P < 0.0001). The quantification of CFR and relative FFR(a) using angiographic image data was validated in a swine model. This angiographic technique can potentially be used for coronary physiological assessment during routine cardiac catheterization.
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Affiliation(s)
- Zhang Zhang
- Department of Radiological Sciences, University of California, Irvine, USA
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Verhoeff BJ, van de Hoef TP, Spaan JAE, Piek JJ, Siebes M. Minimal effect of collateral flow on coronary microvascular resistance in the presence of intermediate and noncritical coronary stenoses. Am J Physiol Heart Circ Physiol 2012; 303:H422-8. [PMID: 22730389 DOI: 10.1152/ajpheart.00003.2012] [Citation(s) in RCA: 36] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 01/13/2023]
Abstract
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) > 25 mmHg is indicative of collateral flow, P(w) 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 P(w)-based adjustment for collateral flow (HMR(C)). FFR ranged from 0.3 to 1. HMR varied between 1 and 5 and HMR(C) between 0.5 and 4.2 mmHg·cm(-1)·s. HMR was about 37% higher than HMR(C) for stenoses with FFR < 0.6, but for FFR > 0.8, the relative difference was reduced to 4.4 ± 3.4%. In the diagnostically relevant range of FFR between 0.6 and 0.8, this difference was 16.5 ± 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.
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Affiliation(s)
- Bart-Jan Verhoeff
- Department of Cardiology, Academic Medical Center, University of Amsterdam, Amsterdam, The Netherlands
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Govindaraju K, Badruddin IA, Viswanathan GN, Ramesh SV, Badarudin A. Evaluation of functional severity of coronary artery disease and fluid dynamics' influence on hemodynamic parameters: A review. Phys Med 2012; 29:225-32. [PMID: 22704601 DOI: 10.1016/j.ejmp.2012.03.008] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 10/24/2011] [Revised: 03/19/2012] [Accepted: 03/28/2012] [Indexed: 11/29/2022] Open
Abstract
Coronary Artery Disease (CAD) is responsible for most of the deaths in patients with cardiovascular diseases. Diagnostic coronary angiography analysis offers an anatomical knowledge of the severity of the stenosis. The functional or physiological significance is more valuable than the anatomical significance of CAD. Clinicians assess the functional severity of the stenosis by resorting to an invasive measurement of the pressure drop and flow. Hemodynamic parameters, such as pressure wire assessment fractional flow reserve (FFR) or Doppler wire assessment coronary flow reserve (CFR) are well-proven techniques to evaluate the physiological significance of the coronary artery stenosis in the cardiac catheterization laboratory. Between the two techniques mentioned above, the FFR is seen as a very useful index. The presence of guide wire reduces the coronary flow which causes the underestimation of pressure drop across the stenosis which leads to dilemma for the clinicians in the assessment of moderate stenosis. In such condition, the fundamental fluid mechanics is useful in the development of new functional severity parameters such as pressure drop coefficient and lesion flow coefficient. Since the flow takes place in a narrowed artery, the blood behaves as a non-Newtonian fluid. Computational fluid dynamics (CFD) allows a complete coronary flow simulation to study the relationship between the pressure and flow. This paper aims at explaining (i) diagnostic modalities for the evaluation of the CAD and valuable insights regarding FFR in the evaluation of the functional severity of the CAD (ii) the role of fluid dynamics in measuring the severity of CAD.
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Peelukhana SV, Banerjee RK, Kolli KK, Effat MA, Helmy TA, Leesar MA, Schneeberger EW, Succop P, Gottliebson W, Irif A. Effect of heart rate on hemodynamic endpoints under concomitant microvascular disease in a porcine model. Am J Physiol Heart Circ Physiol 2012; 302:H1563-73. [PMID: 22287585 DOI: 10.1152/ajpheart.01042.2011] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 01/06/2023]
Abstract
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-μm 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 < 120 and HR > 120 beats/min, %AS < 50 and %AS > 50, and additionally for DP < 14 and DP > 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 < 120 beats/min and HR > 120 beats/min groups, the values of FFR (0.82 ± 0.02 and 0.82 ± 0.02), CDP (83.15 ± 26.19 and 98.62 ± 26.04), and LFC (0.16 ± 0.03 and 0.15 ± 0.03) were not significantly different (P > 0.05). However, for %AS < 50 and %AS > 50, the FFR (0.89 ± 0.02 and 0.75 ± 0.02), CDP (35.97 ± 25.79.10 and 143.80 ± 25.41), and LFC (0.09 ± 0.03 and 0.22 ± 0.03) were significantly different (P < 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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Affiliation(s)
- S V Peelukhana
- School of Dynamic Systems, Department of Mechanical Engineering, University of Cincinnati, Cincinnati, Ohio 45220, USA
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Konala BC, Das A, Banerjee RK. Influence of arterial wall-stenosis compliance on the coronary diagnostic parameters. J Biomech 2011; 44:842-7. [DOI: 10.1016/j.jbiomech.2010.12.011] [Citation(s) in RCA: 37] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/13/2010] [Revised: 12/08/2010] [Accepted: 12/08/2010] [Indexed: 11/17/2022]
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Kolli KK, Banerjee RK, Peelukhana SV, Helmy TA, Leesar MA, Arif I, Schneeberger EW, Hand D, Succop P, 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 2010; 300:H382-7. [PMID: 20935151 DOI: 10.1152/ajpheart.00412.2010] [Citation(s) in RCA: 23] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/22/2022]
Abstract
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 (CDP(e), 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 < 120 and HR > 120 beats/min, in the presence of epicardial coronary lesions of <50% AS and >50% AS. The mean values of FFR, CDP(e), and LFC were significantly different (P < 0.05) for lesions of <50% AS and >50% AS (0.88 ± 0.04, 0.76 ± 0.04; 62 ± 30, 151 ± 35, and 0.10 ± 0.02 and 0.16 ± 0.01, respectively). The mean values of FFR and CDP(e) were not significantly different (P > 0.05) for variable HR conditions of HR < 120 and HR > 120 beats/min (FFR, 0.81 ± 0.04 and 0.82 ± 0.04; and CDP(e), 95 ± 33 and 118 ± 36). The mean values of LFC do somewhat vary with HR (0.14 ± 0.01 and 0.12 ± 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.
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Affiliation(s)
- Kranthi K Kolli
- Department of Mechanical Engineering, University of Cincinnati, Cincinnati, Ohio 45221-0072, USA
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