Quantitative Measurements of Competitive Flow in Left Internal Mammary Artery Bypass Grafts

    Research output: Contribution to conferenceAbstract

    Abstract

    OBJECTIVE: A low flow rate with diminished wall shear stress in arteries can cause intima hyperplasia and diameter reduction. In coronary artery bypass grafting (CABG) a low flow rate through the graft can cause graft failure (i.e. the string sign effect and occlusion). Arterial grafts bypassing an intermediate or non-significant stenosed coronary artery show higher incidence of graft failure, implicating the importance of competitive flow from the coronary artery. Therefore this experimental study quantifies flow rates, with and without flow competition, for the left internal mammary artery (LIMA). METHODS: 30 Patients undergoing off-pump CABG using LIMA-grafts to bypass left anterior descending (LAD) arteries were included. The LIMA-graft flow rate was measured intra-operatively with Transit Time Flow Measurements (TTFM). Competitive flow was assessed by measuring graft flow rate with and without closing of the LAD. To research the effect of the severity of coronary artery stenosis, patients were divided into three groups based on percentage of LAD-stenosis; Group 1: < 50%, Group 2: 50-70% and group 3: > 70%. RESULTS: There were significant differences in mean flow rate, pulsatility index, back flow, peak systolic flow and peak diastolic flow (Table 1), between LIMA-graft flow measurements with the LAD open and closed. 12 patients (40%) had a LIMA-graft flow rate of < 20 ml/min, which increased to > 20 ml/min after closing of the LAD in 9 patients. Group 3 had a significantly higher LIMA-graft mean flow rate compared to group 1 (40 ± 29 ml/min vs. 22 ± 10 ml/min, p = 0.01) and group 2 (40 ± 29 ml/min vs. 20 ± 8 ml/min, p = 0.02). CONCLUSIONS: LIMA-graft conditions, as previously described in literature, were more favourable when flow competition was absent. Competitive flow from the target coronary artery decreases LIMA-graft flow rate and can be a cause of a low flow rate, possibly resulting in graft failure. Patients with an intermediate or non-significant coronary artery stenosis show more flow competition and significantly lower graft flow rate.
    Original languageEnglish
    Publication statusPublished - 20 Aug 2017
    Event2017 International Coronary Congress: State-of-the-art Surgical Coronary Revascularization - New York Marriot Marquis, New York, United States
    Duration: 18 Aug 201720 Aug 2017
    http://internationalcoronarycongress.com/program/2017/

    Conference

    Conference2017 International Coronary Congress
    Abbreviated titleICC 2017
    CountryUnited States
    CityNew York
    Period18/08/1720/08/17
    Internet address

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    Mammary Arteries
    Transplants
    Coronary Vessels
    Coronary Stenosis
    Coronary Artery Bypass
    Arteries
    Off-Pump Coronary Artery Bypass
    Hyperplasia

    Cite this

    Spoor, P., Halfwerk, F. R., Hagmeijer, R., & Grandjean, J. G. (2017). Quantitative Measurements of Competitive Flow in Left Internal Mammary Artery Bypass Grafts. Abstract from 2017 International Coronary Congress, New York, United States.
    @conference{2ff0d768033d4532870f379f274d2483,
    title = "Quantitative Measurements of Competitive Flow in Left Internal Mammary Artery Bypass Grafts",
    abstract = "OBJECTIVE: A low flow rate with diminished wall shear stress in arteries can cause intima hyperplasia and diameter reduction. In coronary artery bypass grafting (CABG) a low flow rate through the graft can cause graft failure (i.e. the string sign effect and occlusion). Arterial grafts bypassing an intermediate or non-significant stenosed coronary artery show higher incidence of graft failure, implicating the importance of competitive flow from the coronary artery. Therefore this experimental study quantifies flow rates, with and without flow competition, for the left internal mammary artery (LIMA). METHODS: 30 Patients undergoing off-pump CABG using LIMA-grafts to bypass left anterior descending (LAD) arteries were included. The LIMA-graft flow rate was measured intra-operatively with Transit Time Flow Measurements (TTFM). Competitive flow was assessed by measuring graft flow rate with and without closing of the LAD. To research the effect of the severity of coronary artery stenosis, patients were divided into three groups based on percentage of LAD-stenosis; Group 1: < 50{\%}, Group 2: 50-70{\%} and group 3: > 70{\%}. RESULTS: There were significant differences in mean flow rate, pulsatility index, back flow, peak systolic flow and peak diastolic flow (Table 1), between LIMA-graft flow measurements with the LAD open and closed. 12 patients (40{\%}) had a LIMA-graft flow rate of < 20 ml/min, which increased to > 20 ml/min after closing of the LAD in 9 patients. Group 3 had a significantly higher LIMA-graft mean flow rate compared to group 1 (40 ± 29 ml/min vs. 22 ± 10 ml/min, p = 0.01) and group 2 (40 ± 29 ml/min vs. 20 ± 8 ml/min, p = 0.02). CONCLUSIONS: LIMA-graft conditions, as previously described in literature, were more favourable when flow competition was absent. Competitive flow from the target coronary artery decreases LIMA-graft flow rate and can be a cause of a low flow rate, possibly resulting in graft failure. Patients with an intermediate or non-significant coronary artery stenosis show more flow competition and significantly lower graft flow rate.",
    author = "Pien Spoor and F.R. Halfwerk and Rob Hagmeijer and J.G. Grandjean",
    year = "2017",
    month = "8",
    day = "20",
    language = "English",
    note = "2017 International Coronary Congress : State-of-the-art Surgical Coronary Revascularization, ICC 2017 ; Conference date: 18-08-2017 Through 20-08-2017",
    url = "http://internationalcoronarycongress.com/program/2017/",

    }

    Spoor, P, Halfwerk, FR, Hagmeijer, R & Grandjean, JG 2017, 'Quantitative Measurements of Competitive Flow in Left Internal Mammary Artery Bypass Grafts' 2017 International Coronary Congress, New York, United States, 18/08/17 - 20/08/17, .

    Quantitative Measurements of Competitive Flow in Left Internal Mammary Artery Bypass Grafts. / Spoor, Pien; Halfwerk, F.R.; Hagmeijer, Rob ; Grandjean, J.G.

    2017. Abstract from 2017 International Coronary Congress, New York, United States.

    Research output: Contribution to conferenceAbstract

    TY - CONF

    T1 - Quantitative Measurements of Competitive Flow in Left Internal Mammary Artery Bypass Grafts

    AU - Spoor, Pien

    AU - Halfwerk, F.R.

    AU - Hagmeijer, Rob

    AU - Grandjean, J.G.

    PY - 2017/8/20

    Y1 - 2017/8/20

    N2 - OBJECTIVE: A low flow rate with diminished wall shear stress in arteries can cause intima hyperplasia and diameter reduction. In coronary artery bypass grafting (CABG) a low flow rate through the graft can cause graft failure (i.e. the string sign effect and occlusion). Arterial grafts bypassing an intermediate or non-significant stenosed coronary artery show higher incidence of graft failure, implicating the importance of competitive flow from the coronary artery. Therefore this experimental study quantifies flow rates, with and without flow competition, for the left internal mammary artery (LIMA). METHODS: 30 Patients undergoing off-pump CABG using LIMA-grafts to bypass left anterior descending (LAD) arteries were included. The LIMA-graft flow rate was measured intra-operatively with Transit Time Flow Measurements (TTFM). Competitive flow was assessed by measuring graft flow rate with and without closing of the LAD. To research the effect of the severity of coronary artery stenosis, patients were divided into three groups based on percentage of LAD-stenosis; Group 1: < 50%, Group 2: 50-70% and group 3: > 70%. RESULTS: There were significant differences in mean flow rate, pulsatility index, back flow, peak systolic flow and peak diastolic flow (Table 1), between LIMA-graft flow measurements with the LAD open and closed. 12 patients (40%) had a LIMA-graft flow rate of < 20 ml/min, which increased to > 20 ml/min after closing of the LAD in 9 patients. Group 3 had a significantly higher LIMA-graft mean flow rate compared to group 1 (40 ± 29 ml/min vs. 22 ± 10 ml/min, p = 0.01) and group 2 (40 ± 29 ml/min vs. 20 ± 8 ml/min, p = 0.02). CONCLUSIONS: LIMA-graft conditions, as previously described in literature, were more favourable when flow competition was absent. Competitive flow from the target coronary artery decreases LIMA-graft flow rate and can be a cause of a low flow rate, possibly resulting in graft failure. Patients with an intermediate or non-significant coronary artery stenosis show more flow competition and significantly lower graft flow rate.

    AB - OBJECTIVE: A low flow rate with diminished wall shear stress in arteries can cause intima hyperplasia and diameter reduction. In coronary artery bypass grafting (CABG) a low flow rate through the graft can cause graft failure (i.e. the string sign effect and occlusion). Arterial grafts bypassing an intermediate or non-significant stenosed coronary artery show higher incidence of graft failure, implicating the importance of competitive flow from the coronary artery. Therefore this experimental study quantifies flow rates, with and without flow competition, for the left internal mammary artery (LIMA). METHODS: 30 Patients undergoing off-pump CABG using LIMA-grafts to bypass left anterior descending (LAD) arteries were included. The LIMA-graft flow rate was measured intra-operatively with Transit Time Flow Measurements (TTFM). Competitive flow was assessed by measuring graft flow rate with and without closing of the LAD. To research the effect of the severity of coronary artery stenosis, patients were divided into three groups based on percentage of LAD-stenosis; Group 1: < 50%, Group 2: 50-70% and group 3: > 70%. RESULTS: There were significant differences in mean flow rate, pulsatility index, back flow, peak systolic flow and peak diastolic flow (Table 1), between LIMA-graft flow measurements with the LAD open and closed. 12 patients (40%) had a LIMA-graft flow rate of < 20 ml/min, which increased to > 20 ml/min after closing of the LAD in 9 patients. Group 3 had a significantly higher LIMA-graft mean flow rate compared to group 1 (40 ± 29 ml/min vs. 22 ± 10 ml/min, p = 0.01) and group 2 (40 ± 29 ml/min vs. 20 ± 8 ml/min, p = 0.02). CONCLUSIONS: LIMA-graft conditions, as previously described in literature, were more favourable when flow competition was absent. Competitive flow from the target coronary artery decreases LIMA-graft flow rate and can be a cause of a low flow rate, possibly resulting in graft failure. Patients with an intermediate or non-significant coronary artery stenosis show more flow competition and significantly lower graft flow rate.

    M3 - Abstract

    ER -

    Spoor P, Halfwerk FR, Hagmeijer R, Grandjean JG. Quantitative Measurements of Competitive Flow in Left Internal Mammary Artery Bypass Grafts. 2017. Abstract from 2017 International Coronary Congress, New York, United States.