Compliance mismatch between artificial blood vessel and host vessel can cause abnormal hemodynamics and is the main mechanical trigger of intimal hyperplasia(IH)after transplantation.To explore the specific effects of...Compliance mismatch between artificial blood vessel and host vessel can cause abnormal hemodynamics and is the main mechanical trigger of intimal hyperplasia(IH)after transplantation.To explore the specific effects of the degree of compliance mismatch on hemodynamics,the concept of“compliance mismatch degree”was defined in this paper.Numerical results showed that when the compliance mismatch degree was less than-22.21%or more than 3.16%,the minimum WSS in the anastomotic site was less than the safety threshold of 0.5 Pa,which is easy to induce IH.In addition,the compliance mismatch caused different radial displacements first,which in turn affected the hemodynamics.Inspired by this,a novel medium convex artificial blood vessel was proposed,and the simulation results theoretically validated its desired effect on reducing the compliance mismatch.An increase of 0.22 mm in the diameter of the artificial blood vessel corresponded to a decrease of 0.88%in compliance mismatch degree.The feasibility of preparing real medium convex artificial blood vessel was also investigated.The PLCL medium convex artificial blood vessel with good mechanical properties was prepared by dip-coating and electrospinning composite method.These findings are valuable for the design and preparation of novel artificial blood vessel which can make up for the mismatch of compliance.展开更多
Small-diameter artificial blood vessels are prone to cause intimal hyperplasia(IH)after transplantation,which leads to restenosis and low long-term patency rates.The main biomechanical factor for IH formation is the c...Small-diameter artificial blood vessels are prone to cause intimal hyperplasia(IH)after transplantation,which leads to restenosis and low long-term patency rates.The main biomechanical factor for IH formation is the compliance mismatch between the artificial and host blood vessels which can cause abnormal hemodynamics.Although there have been many studies on vascular compliance mismatches,however,little attention has been paid to the effect of the degree of compliance mismatch between graft and the host vessel on hemodynamics.At present,the research on compliance mismatch between the artificial and host blood vessels is still very limited,especially with regard to the specific impact of the compliance mismatch degree on hemodynamics.Therefore,three end-to-end anastomosis models(the compliance of the artificial blood vessel is lower than,similar to,and higher than that of the host blood vessel,called model 1,model 2,model 3,respectively)were constructed and simulated in this study.Simulation results showed that the radial displacement difference between the artificial and host blood vessels were 0.281 mm,0.183 mm and 0.485 mm in model 1,model 2 and model 3,respectively.A low-velocity recirculation zone near the distal anastomosis was formed in model 1 which resulted in excessively low TAWSS(9.261 E-5Pa)and high OSI(0.497).Similarly,a low-velocity recirculation zone near the proximal anastomosis was formed in model 3 and lead to low TAWSS(6.007 E-4Pa)and high OSI(0.480).However,there was no low-velocity recirculation zone near the anastomosis stoma in model 2.The results are instructive for the design and preparation of artificial blood vessels.展开更多
This paper presents a decoupling theory named as Vascular Loading Decoupling Technique (VLDT), extended from the beat-based Tissue Control Method (TCM), for noninvasive measurement of real-time-based intra-arterial bl...This paper presents a decoupling theory named as Vascular Loading Decoupling Technique (VLDT), extended from the beat-based Tissue Control Method (TCM), for noninvasive measurement of real-time-based intra-arterial blood pressure and dynamic compliance of blood vessel. Both VLDT and TCM are based upon the decoupling theory to cause the arterial pulsation without the influence from surrounding tissues and measure the variations of the vascular diameter at critical depth. Meanwhile, the AC part of blood pressure is lost, that is, the reference pressure for AC controller is absent as well. To remedy this problem, VLDT employs Step-Hold control rules and cubic spline curve fitting technique to estimate the reference pressure, identify the impedance of blood vessel, and calculate the AC control gain at Hold stage, then track the AC part of blood pressure and compute the real-time arterial blood pressure at Step stage by turns, which makes the real time measurement feasible;moreover, the dynamic compliance of blood vessel can be extracted from real-time impedances of blood vessel. Since the compliance of blood vessel is decoupled from surrounding tissues, it is valuable for diagnosing the severity of vascular sclerosis. The simulation results showed that the VLDT approach is superiority over TCM. This could provide new prospective to circulatory medicine research.展开更多
基金This work was supported by the Natural Science Foundation for Key Program of Jiangsu Higher Education Institutions,China[Nos.19KJA610004].
文摘Compliance mismatch between artificial blood vessel and host vessel can cause abnormal hemodynamics and is the main mechanical trigger of intimal hyperplasia(IH)after transplantation.To explore the specific effects of the degree of compliance mismatch on hemodynamics,the concept of“compliance mismatch degree”was defined in this paper.Numerical results showed that when the compliance mismatch degree was less than-22.21%or more than 3.16%,the minimum WSS in the anastomotic site was less than the safety threshold of 0.5 Pa,which is easy to induce IH.In addition,the compliance mismatch caused different radial displacements first,which in turn affected the hemodynamics.Inspired by this,a novel medium convex artificial blood vessel was proposed,and the simulation results theoretically validated its desired effect on reducing the compliance mismatch.An increase of 0.22 mm in the diameter of the artificial blood vessel corresponded to a decrease of 0.88%in compliance mismatch degree.The feasibility of preparing real medium convex artificial blood vessel was also investigated.The PLCL medium convex artificial blood vessel with good mechanical properties was prepared by dip-coating and electrospinning composite method.These findings are valuable for the design and preparation of novel artificial blood vessel which can make up for the mismatch of compliance.
基金This work was supported by the Natural Science Foundation,China for Key Program of Jiangsu Higher Education Institutions[Nos.19KJA610004,17KJA540002].
文摘Small-diameter artificial blood vessels are prone to cause intimal hyperplasia(IH)after transplantation,which leads to restenosis and low long-term patency rates.The main biomechanical factor for IH formation is the compliance mismatch between the artificial and host blood vessels which can cause abnormal hemodynamics.Although there have been many studies on vascular compliance mismatches,however,little attention has been paid to the effect of the degree of compliance mismatch between graft and the host vessel on hemodynamics.At present,the research on compliance mismatch between the artificial and host blood vessels is still very limited,especially with regard to the specific impact of the compliance mismatch degree on hemodynamics.Therefore,three end-to-end anastomosis models(the compliance of the artificial blood vessel is lower than,similar to,and higher than that of the host blood vessel,called model 1,model 2,model 3,respectively)were constructed and simulated in this study.Simulation results showed that the radial displacement difference between the artificial and host blood vessels were 0.281 mm,0.183 mm and 0.485 mm in model 1,model 2 and model 3,respectively.A low-velocity recirculation zone near the distal anastomosis was formed in model 1 which resulted in excessively low TAWSS(9.261 E-5Pa)and high OSI(0.497).Similarly,a low-velocity recirculation zone near the proximal anastomosis was formed in model 3 and lead to low TAWSS(6.007 E-4Pa)and high OSI(0.480).However,there was no low-velocity recirculation zone near the anastomosis stoma in model 2.The results are instructive for the design and preparation of artificial blood vessels.
文摘This paper presents a decoupling theory named as Vascular Loading Decoupling Technique (VLDT), extended from the beat-based Tissue Control Method (TCM), for noninvasive measurement of real-time-based intra-arterial blood pressure and dynamic compliance of blood vessel. Both VLDT and TCM are based upon the decoupling theory to cause the arterial pulsation without the influence from surrounding tissues and measure the variations of the vascular diameter at critical depth. Meanwhile, the AC part of blood pressure is lost, that is, the reference pressure for AC controller is absent as well. To remedy this problem, VLDT employs Step-Hold control rules and cubic spline curve fitting technique to estimate the reference pressure, identify the impedance of blood vessel, and calculate the AC control gain at Hold stage, then track the AC part of blood pressure and compute the real-time arterial blood pressure at Step stage by turns, which makes the real time measurement feasible;moreover, the dynamic compliance of blood vessel can be extracted from real-time impedances of blood vessel. Since the compliance of blood vessel is decoupled from surrounding tissues, it is valuable for diagnosing the severity of vascular sclerosis. The simulation results showed that the VLDT approach is superiority over TCM. This could provide new prospective to circulatory medicine research.
