The hemodynamics changes of the common carotid arteries in 10 SD rats were measured with a color doppler flowmetry in an attempt to define the changes resulting from end-to-end anastomosis. The left common carotid arteries were divided and followed by end-to-end anastomosis. The systolic mean peak velocities in the left arteries were measured at the proximal, distal and anastomotic sites and in the right intact arteries as well at 6, 12, 24, 48, 72 and 120 hours after repair. The percentage of area reduction at anastomosis was calculated from these data. The results indicated that the systolic mean peak velocity at the anastomotic sites was significantly increased as compared to the velocity at the proximal, distal and contralateral sites (P lt; 0.05). The velocity at the distal sites was significantly lower than that from the proximal and contralateral sites (P lt; 0.05), the mean percentage of the reduction was 33.18% and 33.33%, respectively. From 6 hours to 120 hours after anastomosis of arteries there was various degree of narrowing at the site of anastomosis. The mean per cent of stenosis was 42.48%. It was concluded that from 6 to 120 hours after end-to-end anastomosis of the small arteries, the velocity at the anastomotic site was increased as compared to the velocities at pre- and post-anastomotic sites. The increase of velocity at the site of anatomosis was caused by stenosis at the anastomosis.
ObjectiveTo observe ocular ischemic appearance (OIA) associated with carotid artery stenosis and its effects on the hemodynamics of central retinal artery (CRA) and ophthalmic artery (OA). MethodsA total of 30 normal persons and 60 patients with carotid artery stenosis diagnosed by color Doppler flow imaging (CDFI) and digital subtraction angiography (DSA) were enrolled in this prospective study.Sixty patients were randomly divided into 2 groups:30 patients with the carotid artery stenosis degree < 60% and 30 cases with the carotid artery stenosis degree≥60%. Thirty normal persons were enrolled in the normal control group. All patients underwent a comprehensive eye examination to determine if OIA exists. The Doppler spectral patterns of CRA and OA were observed by CDFI. The peak systolic velocity (PSV), end diastolic velocity (EDV), blood vessel diameter (BVD) and resistance index (RI) of CRA and OA were measured. ResultsIn the group of the carotid artery stenosis degree≥60%, 24/30 patients (80.0%) had the ophthalmic symptoms and 9/30 patients (30.0%) had ophthalmic signs. In the group of the carotid artery stenosis degree < 60%, 9/30 patients (30.0%) had the ophthalmic symptoms and 3/30 patients (10.0%) had ophthalmic signs. For patients with≥60% stenosis, CDFI revealed a bread-like waveform of CRA, and single peak of OA instead of the typical 3-peak/2-notch waveform. For patients with < 60% stenosis, CDFI revealed a normal pattern of CRA and OA (3-peak/2-notch). The PSV(t=5.255, P=0.007) and EDV(t=4.949, P=0.005) of CRA in the stenosis≥60% group were statistically decreased compared to the normal control group, but the BVD(t=0.457, P > 0.05)and RI(t=0.213, P > 0.05)were normal. The PSV, EDV, BVD and RI of CRA in the stenosis < 60% group were normal(P > 0.05). The PSV(t=4.457, P=0.010)and EDV(t=4.588, P=0.009)of CRA in the stenosis≥60% group were statistically decreased compared to the stenosis < 60% group, but the BVD and RI were the same between these 2 groups. ConclusionPatients with carotid stenosis≥60% had a higher OIA incidence, reduced PSV, EDV of their CRA, while had no significant changes of OA hemodynamics.
PURPOSE:To investigate the relationship between the development of the diabetic retinopathy(DR)and the changes of ocular hemodynamics. METHODS:The hemodynamic parameters (Vmax,Vmin,RI)of central relinal artery(CRA )and central retinal vein(CRV)were measured both in the diabetes mellitus(DM) group(72 cases)and the control group(28 cases)with color Doppler flow imaging(Acuson-128XP/10). RESULT:The hemodynamic changes in CRA and CRV in the different stages of DR had their own characteristicS. The blood flow in CRA of the DM patients without DR was higher than that of the control (Plt;0.05). With tile deterioration of the retinopathy the blood flow in CRA decreased. The velocity of the blood flow in CRA of the proliferative DR group was less than that in the control ,DM without DR patients and background DR patients(Plt;0.05). The velocity of the flow in CRV of the DM patients was higher than that of control (Plt;0.001 )and exhibited its remarkable pulsative pattern. CONCLUSIONS:The changes of the hemodynamics in CRA.CRV was associated with the development of the diabetic retinopathy. （Chin J Ocul Fundus Dis,1997,13: 210-212 ）
Objective To investigate the hemodynamic performance of valved bovine jugular vein conduits (BJVC) for right ventricular outflow tract reconstruction in canine model. Methods The BJVC that were treated with the glutaraldehyde were implanted between the pulmonary artery and right ventricle in seven young canines. Right ventricular and pulmonary artery pressures were measured directly before and after the implantation. Hemodynamic evaluations were carried out by echocardiography and cardiac catheterization after the implantation. Results Seven canines were survival one year after the implantation. The pulmonary artery pressures (including systolic pressure, diastolic pressure and mean pressure) had not significantly changed after reconstruction with the conduits. The right ventricular diastolic pressures had not increased after the reconstruction, but the right ventricular systolic pressure and mean pressure had increased. One year later, the echocardiography showed valve motion with no obvious thickening of the leaflets. No graft kinking or obvious regurgitation of the valve was observed. Cardiac catheterization and angiography showed that the pressure gradients between the right ventricle and the conduits varied from 3 to 19mmHg, the diastolic pressures in the conduits were higher than that of right ventricle((Plt;)0.01), and the conduits and pulmonary arteries had no obvious obstruction. Conclusion The glutaraldehyde-fixed bovine jugular vein conduit has good hemodynamic performance in the pulmonary circulation.
Objective To study the influence of the pedicle length on the perforator flaps in hemodynamics. Methods Four mature swine (2 males, 2 females; weight, 23.0±2.0 kg) were applied to the experiment.Two transverse abdominal skin flaps, based on the superior epigastric pedicle orits rectus abdominal muscle perforators, were designed; each swine was used as its own control. At 2 hours and 1, 2, 3 weeks postoperatively, the skin paddle perfusion and the blood stream velocity in the superior epigastric artery were measured by the Laser Doppler Flowmeter and the Color Doppler Ultrasound, respectively. Flap survival percentages were calculated by the grid method at 1 week postoperatively. The swine were euthanatized, and they underwent angiography at 3 weeks postoperatively. Results At 2 hours and 1 week after operation, edema of the perforator flaps with the superior epigastric pedicle was more severe than that of the skin flaps with the rectus abdominal muscle perforator, and the skin perfusion had a statistical difference between the two kindsof flaps (Plt;0.05). The skin paddle viability and the skin perfusion had nostatistical difference after the first week postoperatively (Pgt;0.05). At 2hours and 1 week after operation, the blood stream velocity in the superior epigastric artery in the perforator flap with the superior abdominal artery pediclewas reduced, and there was a statistical difference between the two kinds of flaps (Plt;0.05); however, the velocity was almost the same after the first week postoperatively. Conclusion The excessively long pedicle of the perforator skin flap may have an unfavorable influence on the flap perfusion,especially during the first week after operation, because of the vascular compromise during the dissection of the long pedicle. The blood vessel anastomosis atthis level of the blood vessels may have no relationship with the perforator flap in hemodynamics. This study can also indicate that the ligation of the branches in the recipient vessels cannot make the perforator flaps overperfused.
ObjectiveTo investigate the expression of tumor necrosis factor α(TNF-α ) in isolated rat heart at different time points after myocardial hypoxia/reoxygenation. MethodsThe isolated langendorff perfused rat heart model was established. Forty-eight SD rats were randomly divided into four groups: a sham group, hypoxia/reoxygenation groups including a H/R 0.5 h group, a 1 h group and a 2 h group. The heart rate(HR), the 1eft ventricular development pressure(LVDP), maximal rates of increase/decrease of the left ventricular pressure(±dp/dtmax) were continuously recorded. The concentrations of TNF-α and creatine kinase-MB(CK-MB) in myocardium, mRNA expression of TNF-α in myocardium were tested. Ultra structure of myocardium was observed under electron microscope. ResultsThe levels of LVDP, ±dp/dtmax, and HR of hypoxia/reoxygenation group were significantly lower than those in the sham group(P<0.05).The levels of TNF-α and CK-MB and the expressions of TNF-α at mRNA level in the hypoxia/reoxygenation group were higher than those in the sham group(P<0.05).There were significant differences in the above parameters among the H/R 0.5 h group, the 1 h group, the 2 h group(P<0.05).The concentrations of TNF-α and CK-MB, the mRNA expression of TNF-α were higher in the I/R 2 h group than those in the other two groups. ConclusionThe high expression of TNF-α in myocardium after myocardial hypoxia/reoxygenation in rats is related to the degree of myocardium damage and may lead to myocardial injury.
Objective To investigate the feasibility of a long-term left ventricular assist device placed in the aortic valve annulus for terminal cardiopathy. Methods An implantable aortic valve pump （23ram outer diameter, weighing 31g） was developed. There were a central rotor and a stator in the device. The rotor was consisted of driven magnets and an impeller, the stator was consisted of a motor coil with an iron core and outflow guide vanes. The device was implanted identical to an aortic valve replacement, occupying no additional anatomic space. The blood was delivered directly from left ventricle to the aortic root by aortic valve pump like natural ventricle, neither connecting conduits nor ＂bypass＂ circuits were necessary, therefore physiologic disturbances of natural circulation was less. Results Aortic valve pump was designed to cycle between a peak flow and zero net flow to approximate systole and diastole. Bench testing indicated that a blood flow of 7L/min with 50 mmHg（1kPa = 7.5mmHg） pressure could be produced by aortic valve pump at 15 000r/min. A diastole aortic pressure of 80mmHg could be maintained by aortic valve pump at 0L/min and the same rotating speed. Conclusions This paper exhibits the possibility that an aortic valve pump with sufficient hemodynamic capacity could be made in 23mm outer diameter, 31g and it could be implantable. This achievement is a great progress to extend the applications of aortic valve pump in clinic and finally in replacing the natural donor heart for heart transplantation. Meanwhile, this is only a little step, because many important problems, such as blood compatibility and durability, require further investigation.
Abstract: Objective To investigate the in vivo effective orifice area (EOA) and whether prosthesispatient mismatch (PPM) is going to happen after 19mm St.Jude Regent valves replacement were performed. Methods Twentythree patients with valvular heart diseases were divided into 2 groups according to aortic annular diameter. 19mm St. Jude Regent valves were replaced in aortic valve place (Regent valve group), and 21mm other doubleleaflet mechanical valves were replaced in aortic place (other valves group). All of the operations were accomplished under cardiopulmonary bypass in West China Hospital. All of the patients were followed up in 3 to 6 months after their surgery processes. Color Doppler echocardiography was used to measure the hemodynamic parameters in their followup. Then left ventricular mass (LV mass), EOA and effective orifice area index (EOAI) etc. were calculated and compared by using SPSS 12.0. Results No cardiac episodes were detected during the perioperative period and 36 months after operation. LVmass reduced in 36 months after operation in both groups. No statistical significance of EOA, EOAI and LVmass reduction were detected between the two groups. Conclusions (1)The EOA and in vivo hemodynamic effects of 19mm Regent valve are similar to 21mm other double leaflet mechanical valve. (2)It is safe to use 19mm Regent valve in those patients whose aortic annular diameter are small and need double valve replacement. Using 19mm Regent valve will not cause short time cardiac episodes and PPM. (3)More further works should be done to make sure what is the standard of PPM in Chinese people, such as enlarging the patients number and prolonging the followup time. (4) Further clinical and followup works should be done to make St.Jude Regent valve’s feature out.
The implantation of biventricular assist device (BiVAD) is more challenging than that of left ventricular assist device for the interaction in the process of multiple input and output. Besides, ventricular assist device (VAD) often runs in constant speed (CS) mode in clinical use and thus BiVAD also faces the problems of low pulsation and imbalance of blood volume between systemic circulation and pulmonary circulation. In this paper, a delay assist mode for a VAD by shortening the support time of VAD was put forward. Then, the effect of the delay mode on cardiac output, pulsation and the function of the aortic valve was observed by numerical method and the rules of hemodynamics were revealed. The research showed that compared with VAD supported in CS mode, the VAD using delay mode in systolic and diastolic period proposed in this paper could meet the demand of cardiac output perfusion and restore the function of the arterial valves. The open ratio of aortic valve (AV) and pulmonary valve (PV) increased with the time set in delay mode, and the blood through the AV/PV helped to balance the left and the right cardiac volume. Besides, delay mode also improved the pulsation index of arterial blood flow, which is conducive to the recovery of the ventricular pulse function of patients.
ObjectiveTo observe the effects of carotid artery stenting (CAS) on ophthalmic artery blood flow in patients with ischemic ophthalmopathy (IOP).MethodsA prospective case-control study. Sixty IOP patients (60 eyes) who met inclusive criteria for CAS were enrolled in this study. There was 50% stenosis of internal carotid artery on one side at least confirmed by color doppler flow imaging (CDFI). Among 60 eyes, there were 3 eyes with central retinal artery occlusion, 15 eyes with retinal vein occlusion, 37 eyes with ischemic optic neuropathy, 5 eyes with ocular ischemia syndrome. The patients were randomly divided into CAS group (32 eyes of 32 patients) and medicine therapy group (28 eyes of 28 patients). The difference of age (t=1.804) and sex (χ2=1.975) between two groups was not significant (P＞0.05). The examinations of fundus fluorescein angiography (FFA), CDFI and digital substraction angiography (DSA) were performed before, 1 week and 6 months after treatment. The following parameters were recorded: arm-retinal circulation time (A-Rct), peak systolic velocity (PSV), end-diastolic velocity (EDV), and resistance index (RI) in the ophthalmic artery (OA) and central retinal artery (CRA), and the best corrected visual acuity (BCVA).ResultsThere was no significant differences in A-Rct (t=1.354) and BCVA (t=0.376) between the two groups before treatment (P＞0.05). Also, there was no significant differences in PSV (t=−0.294, −2.446), EDV (t=0.141, −0.305), and RI (t=−0.222, −0.694) of OA and CRA between the two groups before treatment before treatment (P＞0.05). Compared with the medicine therapy group, the lower A-Rct was found in the CAS group at different time points after the treatment. The difference was significant on 1 week after treatment (t=−3.205, P＜0.05), but not on 6 months after treatment (t=1.345, P＞0.05). The BCVA of eyes in the two groups were increasing with the extending of time of therapy. Compared with the medicine therapy group, the better BCVA was found in the CAS group at different time points after the treatment (t=0.800, 1.527; P＜0.05). Compared with the medicine therapy group, the higher PSV, EDV and lower RI of OA and CRA were found in the CAS group at different time points after the treatment. (P＜0.05).ConclusionCompared with conventional medicine therapy, CAS shows earlier effects in improving ocular hemodynamics for IOP patients with carotid artery stenosis, which benefits visual function improvement of the patients.