| Objective:To design a new gutter technique,and to explore the related factors and effects of the flow of the arch branch in the valve simulation platform,evaluate its effectiveness and feasibility,and provide a reference for clinical use.Methods:The physiological aortic pulsation conditions of human body were simulated on the valve simulation platform.Thoracic Endovascular Aortic Repair(TEVAR)was simulated on the valve simulation platform.A covered stent was placed in the simulated aortic arch to block the three-branch flow of the arch,and its proximal end crossed the brachiocephalic artery 1.5-2cm.Before the stent is placed,the gutter technology is established,that is,the long sheath of the blood vessel and the configured hard guide wire are placed at the proximal end of the simulated aortic arch,and the head end is placed at the simulated ascending aorta and crosses the stent 2cm,so that a gutter is formed between the stent and the simulated aortic arch wall,which saves a certain space for the water flow of the ’aortic arch ’ branch.The influencing factors of the design are as follows:the water pressure is 100 mmHg,80 mmHg and 60 mmHg respectively,and the inner diameter of the long sheath of the blood vessel is 6F,8F and 10F respectively.The position of the long sheath of the blood vessel in the simulated aortic arch is:a single long sheath is placed in the brachiocephalic artery,left subclavian artery and left femoral artery respectively;two long sheaths were placed in the left subclavian artery+brachiocephalic artery,left subclavian artery+left femoral artery and brachiocephalic artery+left femoral artery.The three long sheaths are the left subclavian artery+brachiocephalic trunk+left femoral artery.According to the inner diameter of the long sheath of blood vessels from small to large,they were divided into experimental group 1,experimental group 2 and experimental group 3.The observed indicators are:right carotid artery and left carotid artery flow velocity,flow pressure.The effects of the above different factors on the flow velocity and flow pressure of the simulated aortic arch were studied.The optimal group suitable for clinical application was obtained through research.Then under the condition of the optimal group,CT scan was performed to observe the gutter area between the main stent and the wall at the opening of the right common carotid artery and the left common carotid artery.Using SPSS statistical software for data analysis,measurement data using mean± square.Results:General experimental results:The valve simulation uses the platform to simulate the inner diameter of the ascending aorta at 2cm before the brachiocephalic trunk is about 33mm,the inner diameter of the proximal end of the brachiocephalic trunk artery is about 12mm,the inner diameter of the right carotid artery is about 10mm,and the inner diameter of the simulated left carotid artery is about 7mm.The diameter of the proximal end of the selected covered stent was 40 mm,the diameter of the distal end was 38 mm,and the length was 200 mm.A total of 474 experiments were performed,405 were successful,and the success rate was 85.4%.The results of the experimental process:the valve simulation used the platform to set the external pressure to 100 mmHg,80 mmHg and 60 mmHg,the corresponding ’output per minute ’ was 4.2L,3.5L,2.56L,’stroke output ’ was 70ml,58.3ml,42.7ml,and the contraction frequency of the experimental medium pump station was 70 times/min.When the external pressure was set to 60 mmHg,the experimental group with the maximum pressure on the left and right carotid arteries was 8F vascular sheath implanted through the left subclavian artery and the left femoral artery.The pressure was 58.06 ± 0.09 mmHg and 56.3 ± 0.14 mmHg,respectively.The flow rate was 127.928 ± 10.22 cm/s and 150.188± 8.43 cm/s.The pressure generated could not reach the pressure required to maintain brain protection.The external water flow pressure was set to 100 mmHg in the experiment:When a single vascular sheath was placed,there was no significant difference in the recovery of left carotid artery flow when the vascular sheath was introduced into the right subclavian artery(P>0.05).There were significant differences between the other experimental groups and the control group(P<0.05).At this time,the experimental group 1(the diameter of the vascular sheath was 6F)was implanted in the left subclavian artery.The results were better.The flow velocity generated by the right carotid artery was 225.046 ± 19.36cm/s,and the pressure was 81.18±0.11mmHg.The flow velocity of the left carotid artery was 213.934 ± 7.65cm/s,and the pressure was 81.24 ±0.05 mmHg.When two vascular sheaths were placed,there were statistical differences between the experimental groups and the control group(P<0.05).In the experimental group 1(the inner diameter of the vascular sheath was 6F),the results of vascular sheath placement in the left subclavian artery and the left femoral artery were better.The flow velocity generated by the right carotid artery was 304.3 ± 37.36cm/s,and the pressure was 82.92 ± 0.04mmHg.The flow velocity generated by the left carotid artery was 264.542 ± 23.91cm/s,and the pressure was 84.24 ± 0.05mmHg.When three vascular sheaths were placed,there were statistical differences between the experimental groups and the control group(P<0.05).The results of the experimental group 1(the inner diameter of the vascular sheath was 6F)were better.The water flow velocity produced by the right carotid artery was 305.354± 25.64cm/s,the pressure was 88.06 ± 0.09mmHg,and the flow velocity of the left carotid artery was 289.766±13.26cm/s,and the pressure was 88.32±0.11 mmHg.When the external water pressure was set to 80 mmHg,the pressure and velocity of bilateral carotid arteries decreased significantly.When a single vascular sheath was placed,the experimental group 1(the inner diameter of the vascular sheath was 6F)was better in the left subclavian artery.The flow velocity of the right carotid artery was 159.586 ± 11.88cm/s,and the pressure was 62.1 ± 0.26 mmHg.The flow velocity of the left carotid artery was 161.84 ± 10.9cm/s,and the pressure was 61.3 ± 0.12 mmHg.When two vascular sheaths were placed,the experimental group 1(the inner diameter of the vascular sheath was 6F)had a better result in placing the vascular sheath in the left subclavian artery.The water flow velocity generated by the right carotid artery was 173.476 ± 17.12cm/s,and the pressure was 61.12 ± 0.04 mmHg.The water flow velocity generated by the left carotid artery was 168.116± 17.19cm/s,and the pressure was 62.9± 0.07 mmHg.When three vascular sheaths were placed,the flow velocity and pressure of the right carotid artery in the experimental group 1(the diameter of the vascular sheath was 6F)were 266.33±13.16cm/s and 67.42±0.11mmHg,respectively.The flow velocity and pressure of the left carotid artery were 193.9 ± 8.72cm/s and 68.44 ± 0.05mmHg,respectively.The experimental optimal group was the gutter established by placing the long sheath of the blood vessel and adding the hard guide wire to the ascending aorta at the same time in the left subclavian artery and the left femoral artery in the experimental group 1.By drawing the gutter area,the area of the gutter at the right carotid artery in the optimal group was 1.482 cm2,the area of the right carotid artery was 3.14 cm2,and the opening rate was 47.2%.In the optimal group,the area of the gutter at the left carotid artery was 0.5630 cm2,the area of the left carotid artery was 1.53 cm2,and the opening rate was 36.8%.Conclusion:The gutter technique is effective and feasible in the valve simulation platform to protect the flow of the partial branch of the arch.It is the most effective to place the long sheath and hard guide wire in the left subclavian artery and the left femoral artery at the same time to protect the flow of the partial branch of the arch. |
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