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. 2023 Mar 3;18(3):e0281423.
doi: 10.1371/journal.pone.0281423. eCollection 2023.

Patient-specific computational simulation of coronary artery bypass grafting

Wei Wu  1   2 , Anastasios Nikolaos Panagopoulos  1 , Charu Hasini Vasa  1   2 , Mohammadali Sharzehee  1 , Shijia Zhao  1   2 , Saurabhi Samant  1 , Usama M Oguz  1   2 , Behram Khan  1 , Abdallah Naser  1 , Khaled M Harmouch  1 , Ghassan S Kassab  3 , Aleem Siddique  4 , Yiannis S Chatzizisis  1   2
Affiliations

Patient-specific computational simulation of coronary artery bypass grafting

Wei Wu et al. PLoS One. .

Erratum in

Abstract

Introduction: Coronary artery bypass graft surgery (CABG) is an intervention in patients with extensive obstructive coronary artery disease diagnosed with invasive coronary angiography. Here we present and test a novel application of non-invasive computational assessment of coronary hemodynamics before and after bypass grafting.

Methods and results: We tested the computational CABG platform in n = 2 post-CABG patients. The computationally calculated fractional flow reserve showed high agreement with the angiography-based fractional flow reserve. Furthermore, we performed multiscale computational fluid dynamics simulations of pre- and post-CABG under simulated resting and hyperemic conditions in n = 2 patient-specific anatomies 3D reconstructed from coronary computed tomography angiography. We computationally created different degrees of stenosis in the left anterior descending artery, and we showed that increasing severity of native artery stenosis resulted in augmented flow through the graft and improvement of resting and hyperemic flow in the distal part of the grafted native artery.

Conclusions: We presented a comprehensive patient-specific computational platform that can simulate the hemodynamic conditions before and after CABG and faithfully reproduce the hemodynamic effects of bypass grafting on the native coronary artery flow. Further clinical studies are warranted to validate this preliminary data.

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Conflict of interest statement

Yiannis S. Chatzizisis: Speaker honoraria, advisory board fees and research grant from Boston Scientific Inc., Advisory board fees and research grant from Medtronic Inc., U.S. patent (No. 21072P) for the invention entitled “Patient-specific computational planning of coronary artery bypass grafting”, Co-founder of ComKardia Inc. All other authors have no relevant conflict of interests to disclose. This does not alter our adherence to PLOS ONE policies on sharing data and materials.

Figures

Fig 1
Fig 1. Study aims.
(CABG: coronary artery bypass grafting, LIMA: left internal mammary artery, FFR: fractional flow reserve, CFD: computational fluid dynamics, CCTA: coronary computed tomography angiography, LAD: left anterior descending artery, TAWSS: time-averaged wall shear stress, OSI: oscillatory shear index).
Fig 2
Fig 2. Illustration of the methodologies employed in Aim 2.
A. The post-CABG anatomy (coronary arteries, aorta and grafts) were 3D reconstructed from CCTA, B. In the grafted LAD (proximal to the LIMA anastomosis), we computationally created stenosis of varying severity (magnified in insert), C. All the grafts were computationally removed to create the pre-CABG anatomy, D. Computational fluid dynamics were performed in pre- and post-CABG anatomies (LIMA: left internal mammary artery, CCTA: coronary computed tomography angiography, LAD: left anterior descending artery, LIMA: left internal mammary artery, Rp: proximal vessels resistance, Rd: distal vessels resistance, C: capacitance, Ra: coronary arterial resistance, Ra-micro: coronary venous resistance, Ca: Coronary arterial compliance, Cim: intramyocardial compliance, Pim: intramyocardial pressure).
Fig 3
Fig 3. LAD Pressure and Flow curves across various degrees of LAD stenosis severity pre-CABG at computationally resting and hyperemic conditions (patient 3).
Note the variation of the LAD flow according to the phase of the cardiac cycle and the impact of the increasing severity of LAD stenosis to LAD pressure and flow (LAD: left anterior descending artery).
Fig 4
Fig 4. Comparison of the computationally calculated FFR against angiographic FFR in Aim 1 patients.
Note the high agreement between computational and angiographic FFR. (FFR: fractional flow reserve).
Fig 5
Fig 5. Effect of LIMA grafting on LAD hemodynamics.
Computational calculation of the pre-and post-CABG resting Pd/Pa (resting conditions) and FFR (hyperemic conditions) proximal and distal to the computationally created stenosis. Values are expressed as mean±SD. Note the normalization of FFR by grafting severe stenosis and near normalization of FFR by grafting critical stenoses (red bars; dashed lines represent the FFR ischemic cut-off of 0.80; Pd/Pa: distal pressure/aorta pressure, FFR: fractional flow reserve, CABG: coronary artery bypass grafting, LAD: left anterior descending artery, SD: standard deviation).
Fig 6
Fig 6. Hemodynamic interdependence between LAD and LIMA.
A and B. Note the transition of resting flow dominance from the LAD to LIMA as the severity of LAD stenosis increases. C and D. Cross-sectional flow velocity contours across the LAD and LIMA for varying degrees of computationally created stenosis at peak diastole under computationally resting (C) and hyperemic (D) conditions for patient 3. Note that as the severity of the LAD stenosis increases, the dominant flow shifts from the LAD to LIMA. The transition point from the LAD flow dominance to LIMA flow dominance occurs with severe stenosis at rest and moderate stenosis at hyperemia (LAD: left anterior descending artery, LIMA: left internal mammary artery).
Fig 7
Fig 7. Representative example of low TAWSS and high OSI areas across the LAD and LIMA after CABG at resting conditions (Patient 3).
A. Quantitative results, B. Qualitative results. Note that as the degree of LAD stenosis severity increases, the LIMA lumen area exposed to low TAWSS and high OSI decreases (A, green bars), whereas the LAD lumen area exposed to low TAWSS and high OSI increases (A, red bars). Values are expressed as mean±SD (Purple arrow: LIMA, black arrow: LAD stenosis; LIMA: left internal mammary artery, LAD: left anterior descending artery, TAWSS: time-averaged wall shear stress, OSI: oscillatory shear index).
Fig 8
Fig 8. Schematic presentation of the dominant role of the hemodynamic significance over the anatomical significance of a native artery stenosis on the graft flow.
A. In anatomically significant but non-hemodynamically significant native artery stenoses, the flow through the native artery exceeds the flow through the graft, B. In anatomically and hemodynamically significant native artery stenoses, the flow through the graft exceeds the flow through the native artery (FFR: fractional flow reserve).
See this image and copyright information in PMC

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