Hemodynamics plays a crucial role in the development and progression of coronary atherosclerosis,which is prone to occur in branch bifurcation.A n individual aortic-coronary artery model and three changed bifurcation ...Hemodynamics plays a crucial role in the development and progression of coronary atherosclerosis,which is prone to occur in branch bifurcation.A n individual aortic-coronary artery model and three changed bifurcation angle models are constructed by Mimics and Freeform based on computed tomography angiography.The influence of different coronary bifurcation angles between left main(LM),left anterior descending(LAD),and left circumflex(LCX)on the blood flow field and related hemodynamic parameters are studied.It is shown that a wider bifurcation angle between LAD and LCX can cause a wider low-wall shear stress area,leading to atherosclerosis.Similarly,a decreased angle between LM and LAD is predisposed to prevent atherosclerosis.The results help to better understand the hemodynamic causes of atherosclerosis with various bifurcation angles in coronary arteries and to provide guidance for clinical assessment and prevention.展开更多
Background Bifurcation angles may have an impact on the clinical outcomes of crush stenting. We sought to compare high （≥60°） with low （〈60°） bifurcation angle in patients who underwent either classica...Background Bifurcation angles may have an impact on the clinical outcomes of crush stenting. We sought to compare high （≥60°） with low （〈60°） bifurcation angle in patients who underwent either classical or double kissing （DK） crush stenting for bifurcation lesions from the DKCRUSH-1 data base. Methods There were 212 patients with 220 lesions, some with low-angle （n=138） and some with high-angle （n=74）. Angiography was indexed at 8-month after procedure. Primary endpoint was the occurrence of major adverse cardiac events （MACEs）, defined as cardiac death, myocardial infarction and target lesion revascularization （TLR）. Secondary endpoint included late lumen loss, the rate of restenosis, and final kissing balloon inflation （FKBI）. Results At 8 months, clinical follow-up was 100%; angiographic follow-up was 75% in the low-angle group and 83.3% in the high-angle group. There were no significant differences in the FKBI between the high-angle group （91.43%） and the low-angle group （82.39%）. In the high angle group, there was a significant difference in contrast volume used （P=0.005） but no significant difference in acute gain, minimum lumen diameter （MLD）, late loss and diameter stenosis in the pre-bifurcation segment, post-bifurcation segment or side branch. When lesions were assigned into with- （n=-133） and without-FKBI （n=42）, significant side-branch late loss was seen in the group without-FKBI （（0.65±0.49） mm vs （0.47±0.62） mm, P=0.02）, with a resultant greater restenosis rate （37.68% vs 18.32%, P=0.001）. No difference was detected in the MACE free survival rate between the high and low angle groups （82.39% vs 82.36%, P=0.84）. The rate of stent thrombosis tended to be higher in the lower-angle group although there was no significant difference （P=0.38）. The TLR free survival rate was 87.2% in the with-FKBI group vs 73.5% in the without-FKBI group （P=0.001）. Cox regression analysis showed that the independent predictors for target vessel revascularization were the side branch stent MLD post stenting （hazard ratios （HR） 1.028, 95% CI 2.357-16.233, P=0.002）, lack of FKBI （HR 4.910, 95% CI 4.706-8.459, P=0.001） and unsatisfactory kissing （HR 3.120, 95% CI2.975-5.431, P=0.001）. Conclusions Bifurcation angles do not influence the clinical outcome of crush stenting. Successful final kissing balloon inflation, regardless of bifurcation angles, can predict TLR.展开更多
Bifurcation coronary lesions are relatively frequent in today＇s interventional cardiology practice, averaging between 10%-15% of all interventions （PCIs）. Several percutaneous coronary problems inherent in the tre...Bifurcation coronary lesions are relatively frequent in today＇s interventional cardiology practice, averaging between 10%-15% of all interventions （PCIs）. Several percutaneous coronary problems inherent in the treatment of bifurcation lesions are periprocedural side branch （SB） compromise （composite of SB closure or appearance of significant ostial stenosis after main vessel （MV） stenting causing ischemia） frequently related to periprocedural myonecrosis,展开更多
Background The predictive value of bifurcation angle （BA） for worse events after stenting bifurcation lesions remains to be unknown. The present study was to investigate the dynamic change of BA and clinical relevan...Background The predictive value of bifurcation angle （BA） for worse events after stenting bifurcation lesions remains to be unknown. The present study was to investigate the dynamic change of BA and clinical relevance for patients with coronary bifurcation lesions treated by drug-eluting stent （DES）. Methods BA was calculated by 3-D quantitative coronary analysis from 347 patients in DKCRUSH-II study. Primary endpoint was the occurrence of composite major adverse cardiac events （MACE） at 12-month, including cardiac death, myocardial infarction （MI） and target vessel revascularization （TVR）. Secondary end points were the rate of binary restenosis and stent thrombosis at 12-month. Results Stenting was associated with the reduction of distal BA. The cut-off value of distal BA for predicting MACE was 60°. Distal BA in 〈60° group had less reduction after stenting （（-1.96＋13.58）°vs. （-12.12±23.58）°, P 〈0.001）; two-stent technique was associated with significant reduction of distal BA （△（-4.05±14.20）°）, compared to single stent group （4＋1.55±11.73, P=0.003）; the target lesion revascularization （TLR）, TVR and MACE rate was higher in one-stent group （16.5%, 19.0% and 21.5%）, compared to two-stent group （3.8%, P=0.002; 7.5%, P=0.016; and 9.8%, P=0.024）, respectively. Among patients in ≥60° group, there were no significant differences in distal BA, stent thrombosis （ST）, MI, MACE, death, TLR, TVR between one- and two-stent groups; after stenting procedure, there was only slight change of distal BA in left anterior descending （LAD）-Ieft circumflex （LCX） subgroup （from （88.54±21.33）° at baseline to （82.44±31.72）° post-stenting）, compared to either LAD-diagonal branch （Di）, or LCX-obtuse marginal branch （OM）, or IRCA distal （RCAd） （all P 〈0.001 ）. Conclusion Two-stent technique was associated with significant reduction of distal BA. DK crush stenting had reduced rate of MACE in patients in 〈60° group, compared to one-stent technique.展开更多
In view of engineering application, it is practicable to decompose the aerodynamics into three components： the static aerodynamics, the aerodynamic increment due to steady rotations, and the aerodynamic increment due...In view of engineering application, it is practicable to decompose the aerodynamics into three components： the static aerodynamics, the aerodynamic increment due to steady rotations, and the aerodynamic increment due to unsteady separated and vortical flow. The first and the second components can be presented in conventional forms, while the third is described using a one-order differential equation and a radial-basis-function （RBF） network. For an aircraft configuration, the mathematical models of 6- component aerodynamic coefficients are set up from the wind tunnel test data of pitch, yaw, roll, and coupled yawroll large-amplitude oscillations. The flight dynamics of an aircraft is studied by the bifurcation analysis technique in the case of quasi-steady aerodynamics and unsteady aerodynam- ics, respectively. The results show that： （1） unsteady aerodynamics has no effect upon the existence of trim points, but affects their stability; （2） unsteady aerodynamics has great effects upon the existence, stability, and amplitudes of periodic solutions; and （3） unsteady aerodynamics changes the stable regions of trim points obviously. Furthermore, the dynamic responses of the aircraft to elevator deflections are inspected. It is shown that the unsteady aerodynamics is beneficial to dynamic stability for the present aircraft. Finally, the effects of unsteady aerodynamics on the post-stall maneuverability展开更多
基金The authors are grateful for the support of the Specialized Research Fund for the Doctoral Program of Higher Education(Grant 20131103110025)the Key Program of Science and Technology Plan of Beijing Municipal Education Commission(Grant KZ201710005006)the National Natural Science Foundation of China(Grant 81601557).
文摘Hemodynamics plays a crucial role in the development and progression of coronary atherosclerosis,which is prone to occur in branch bifurcation.A n individual aortic-coronary artery model and three changed bifurcation angle models are constructed by Mimics and Freeform based on computed tomography angiography.The influence of different coronary bifurcation angles between left main(LM),left anterior descending(LAD),and left circumflex(LCX)on the blood flow field and related hemodynamic parameters are studied.It is shown that a wider bifurcation angle between LAD and LCX can cause a wider low-wall shear stress area,leading to atherosclerosis.Similarly,a decreased angle between LM and LAD is predisposed to prevent atherosclerosis.The results help to better understand the hemodynamic causes of atherosclerosis with various bifurcation angles in coronary arteries and to provide guidance for clinical assessment and prevention.
文摘Background Bifurcation angles may have an impact on the clinical outcomes of crush stenting. We sought to compare high （≥60°） with low （〈60°） bifurcation angle in patients who underwent either classical or double kissing （DK） crush stenting for bifurcation lesions from the DKCRUSH-1 data base. Methods There were 212 patients with 220 lesions, some with low-angle （n=138） and some with high-angle （n=74）. Angiography was indexed at 8-month after procedure. Primary endpoint was the occurrence of major adverse cardiac events （MACEs）, defined as cardiac death, myocardial infarction and target lesion revascularization （TLR）. Secondary endpoint included late lumen loss, the rate of restenosis, and final kissing balloon inflation （FKBI）. Results At 8 months, clinical follow-up was 100%; angiographic follow-up was 75% in the low-angle group and 83.3% in the high-angle group. There were no significant differences in the FKBI between the high-angle group （91.43%） and the low-angle group （82.39%）. In the high angle group, there was a significant difference in contrast volume used （P=0.005） but no significant difference in acute gain, minimum lumen diameter （MLD）, late loss and diameter stenosis in the pre-bifurcation segment, post-bifurcation segment or side branch. When lesions were assigned into with- （n=-133） and without-FKBI （n=42）, significant side-branch late loss was seen in the group without-FKBI （（0.65±0.49） mm vs （0.47±0.62） mm, P=0.02）, with a resultant greater restenosis rate （37.68% vs 18.32%, P=0.001）. No difference was detected in the MACE free survival rate between the high and low angle groups （82.39% vs 82.36%, P=0.84）. The rate of stent thrombosis tended to be higher in the lower-angle group although there was no significant difference （P=0.38）. The TLR free survival rate was 87.2% in the with-FKBI group vs 73.5% in the without-FKBI group （P=0.001）. Cox regression analysis showed that the independent predictors for target vessel revascularization were the side branch stent MLD post stenting （hazard ratios （HR） 1.028, 95% CI 2.357-16.233, P=0.002）, lack of FKBI （HR 4.910, 95% CI 4.706-8.459, P=0.001） and unsatisfactory kissing （HR 3.120, 95% CI2.975-5.431, P=0.001）. Conclusions Bifurcation angles do not influence the clinical outcome of crush stenting. Successful final kissing balloon inflation, regardless of bifurcation angles, can predict TLR.
文摘Bifurcation coronary lesions are relatively frequent in today＇s interventional cardiology practice, averaging between 10%-15% of all interventions （PCIs）. Several percutaneous coronary problems inherent in the treatment of bifurcation lesions are periprocedural side branch （SB） compromise （composite of SB closure or appearance of significant ostial stenosis after main vessel （MV） stenting causing ischemia） frequently related to periprocedural myonecrosis,
文摘Background The predictive value of bifurcation angle （BA） for worse events after stenting bifurcation lesions remains to be unknown. The present study was to investigate the dynamic change of BA and clinical relevance for patients with coronary bifurcation lesions treated by drug-eluting stent （DES）. Methods BA was calculated by 3-D quantitative coronary analysis from 347 patients in DKCRUSH-II study. Primary endpoint was the occurrence of composite major adverse cardiac events （MACE） at 12-month, including cardiac death, myocardial infarction （MI） and target vessel revascularization （TVR）. Secondary end points were the rate of binary restenosis and stent thrombosis at 12-month. Results Stenting was associated with the reduction of distal BA. The cut-off value of distal BA for predicting MACE was 60°. Distal BA in 〈60° group had less reduction after stenting （（-1.96＋13.58）°vs. （-12.12±23.58）°, P 〈0.001）; two-stent technique was associated with significant reduction of distal BA （△（-4.05±14.20）°）, compared to single stent group （4＋1.55±11.73, P=0.003）; the target lesion revascularization （TLR）, TVR and MACE rate was higher in one-stent group （16.5%, 19.0% and 21.5%）, compared to two-stent group （3.8%, P=0.002; 7.5%, P=0.016; and 9.8%, P=0.024）, respectively. Among patients in ≥60° group, there were no significant differences in distal BA, stent thrombosis （ST）, MI, MACE, death, TLR, TVR between one- and two-stent groups; after stenting procedure, there was only slight change of distal BA in left anterior descending （LAD）-Ieft circumflex （LCX） subgroup （from （88.54±21.33）° at baseline to （82.44±31.72）° post-stenting）, compared to either LAD-diagonal branch （Di）, or LCX-obtuse marginal branch （OM）, or IRCA distal （RCAd） （all P 〈0.001 ）. Conclusion Two-stent technique was associated with significant reduction of distal BA. DK crush stenting had reduced rate of MACE in patients in 〈60° group, compared to one-stent technique.
文摘In view of engineering application, it is practicable to decompose the aerodynamics into three components： the static aerodynamics, the aerodynamic increment due to steady rotations, and the aerodynamic increment due to unsteady separated and vortical flow. The first and the second components can be presented in conventional forms, while the third is described using a one-order differential equation and a radial-basis-function （RBF） network. For an aircraft configuration, the mathematical models of 6- component aerodynamic coefficients are set up from the wind tunnel test data of pitch, yaw, roll, and coupled yawroll large-amplitude oscillations. The flight dynamics of an aircraft is studied by the bifurcation analysis technique in the case of quasi-steady aerodynamics and unsteady aerodynam- ics, respectively. The results show that： （1） unsteady aerodynamics has no effect upon the existence of trim points, but affects their stability; （2） unsteady aerodynamics has great effects upon the existence, stability, and amplitudes of periodic solutions; and （3） unsteady aerodynamics changes the stable regions of trim points obviously. Furthermore, the dynamic responses of the aircraft to elevator deflections are inspected. It is shown that the unsteady aerodynamics is beneficial to dynamic stability for the present aircraft. Finally, the effects of unsteady aerodynamics on the post-stall maneuverability
