| Objective:To investigate the contrast-enhanced features of postoperative blood flow changes in rabbits with saphenous artery flaps,and provide experimental evidence for early diagnosis of vascular crisis after flap operation.Methods:Eighteen healthy New Zealand rabbits with similar body weight were selected and randomly divided into 3 groups,6 in each group.Group A was a blank control group,group B was an arterial crisis group,and group C was a venous crisis group.The model of rabbit saphenous artery flap was established with rabbit saphenous vein as vascular pedicle in each group.The model of group A was not implanted after operation.The group B was established in the flap model to establish the postoperative ligation and block the saphenous artery.The group C was established in the flap model to establish the postoperative venous crisis model.Using ultrasound and contrast-enhanced ultrasound to collect the Maximal velocity,Quantity of blood flow,Time-strength curve,Time to peak,Peak intensity,Area under the curve of the pedicled artery of the flap at different time periods to monitore the blood perfusion.At the same time,clinical artificial observation data such as color,tension and capillary response of each group were recorded.Statistical analysis of experimental data was performed using SPSS 17 software.Results:1.Artificial observation and evaluation of flap:Blank control group:After the flap model is established,the color of the flap is reddish,the tissue elasticity is possible,and the capillary reaction is normal.The flaps are always ruddy in the flaps of the flap model for 1h to 8h,and the tissue elasticity and tension are moderate.The vascular response is normal.Arterial crisis group: After the establishment of arterial crisis,the color of the flap became lighter,the flap tension was reduced,and the capillary reaction was slightly retarded.At 1 h after the arterial crisis,the flap was pale,the flap tension was low,and the capillary response was slow;2 h after the arterial crisis The color,tension and capillary response of the flaps did not change significantly compared with 1 h.At 4 h after the arterial crisis,the edge of the flap became black,the capillary reaction disappeared.After 8 h of arterial crisis,the flaps all turned black.Venous crisis group: There was no significant change in color,tension,and capillary response of the endothelial valve 1 h after the establishment of venous crisis;1 h after venous crisis,the surface of the flap gradually appeared scattered,the flap was swollen,and the capillary reaction was slightly accelerated;2 h after the venous crisis The color of the flap gradually deepened,the spots increased,the swelling increased,and the capillary reaction accelerated.After 4 h of venous crisis,the spots gradually merged,and many flaky ecchymoses appeared at the edge of the flap;8 h after the venous crisis,the flaps all turned black,capillaries The reaction disappeared.2.Ultrasound evaluation results Group A: Vmax and Q of perforating artery gradually increased with time after establishment of flap model;Group B: Vmax and Q gradually decreased with time after arterial crisis;Group C: Vmax,Q in venous crisis It gradually increased within 1 hour,and gradually decreased in each period from 1 h to 8 h after the venous crisis occurred.3.Contrast-enhanced ultrasound dynamic imaging After establishing the immediate contrast agent in the flap models of groups A,B and C,the ROI region gradually became uniform and obviously strengthened with time.After reaching the peak,the contrast agent slowly subsided.In group A,the degree of contrast enhancement in the ROI region was slightly enhanced compared with the previous period after the establishment of the flap model.In group B,the ROI region was significantly weakened after the establishment of arterial crisis.At 4 h after arterial crisis,there was only a small enhancement in the ROI region,and there was no significant enhancement in the ROI region 8 h after the arterial crisis.In group C,after the establishment of venous crisis,the degree of enhancement of ROI area was slightly enhanced.After 30 minutes of venous crisis,the degree of enhancement of ROI area was significantly enhanced,and the development of vascular area was more obvious.After 1 hour of venous crisis,the degree of enhancement of ROI area was lower than that of the previous stage.At 4 h after the crisis,a small amount of enhancement was still observed in the ROI region.At 8h after the venous crisis,no significant contrast agent was passed through the ROI region.4.Quantitative parameter analysis of contrast-enhanced ultrasound The TTP of group A was gradually shortened with the extension of the establishment time of the flap;the TTP of group B was prolonged in the establishment of arterial crisis and gradually prolonged with time;the TTP of group C was shortened within 30 minutes after the establishment of venous crisis,in the venous crisis The extension was shown for each time period from 30 min to 8 h.The PI and AUC of group A gradually increased with the prolongation of flap establishment time.The PI and AUC of group B gradually decreased with the prolongation of arterial crisis formation.The PI and AUC of group C were less than 30 minutesafter venous crisis.The anterior enlargement gradually decreases in each time period from 30 min to 8 h after the venous crisis.Groups A,B,and C were compared at different time points,P < 0.05,and the difference was statistically significant.The flap models of group A,B and C were established immediately between groups,P>0.05,the difference was not statistically significant.After the establishment of A,B and C vascular crisis,the time points were compared between groups,P<0.05.The difference was statistically significant.Conclusion:Contrast-enhanced ultrasonography can detect the changes of blood flow in the flap after the motor and venous crisis of the rabbit saphenous artery flap.Which can provide an objective diagnosis for the early diagnosis of vascular crisi in adult New Zealand rbbits. |
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