Objective To analyze the influence of COPD on the structure and function of left ventricular. Methods Sixty-nine COPD patients ( mean age: 69. 0 ±7. 8 yrs) and forty healthy controls ( mean age: 67. 8 ±7. 6 yrs) were enrolled in this study. Both groups underwent Doppler echocardiography.Heart rate ( HR) were recorded. Left ventricular end-diastolic volume ( LVEDV) , left ventricular enddiastolic diameter ( LVEDD) , interventricular septum( IVS) , stroke volume ( SV) , and cardiac output ( CO)were measured. The changes of left ventricular were compared between the COPD patients and the healthy controls, and also between the COPD patients with or without chronic cor pulmonale. Results Compared with the healthy controls, movement range of IVS, LVEDD, LVEDV, and SV reduced significantly ( P lt;0. 05) , and HR raised significantly in the COPD patients ( P lt; 0. 05) . CO had no significant difference between two groups ( P gt;0. 05) . Sub-group analysis indicated that the thickness and movement range of IVSwere greater in the patients with cor pulmonale secondary to COPD than those without cor pulmonale ( P lt;0. 05) . Conclusions In COPD patients, left ventricular chamber size decreases, and left ventricular systolic function is impaired. Left ventricular function is impaired more severe in cor pulmonale secondary to COPD than COPD without cor pulmonale.
To evaluate the implantation effect of artificial vascular grafts with recombinant fibrinolytic enzyme factor II (rF II)-immobil ized lumina in animal test. Methods Four mm internal diameter (ID) polyurethane (PU) artificial vascular grafts were prepared by di pping and leaching method. The micro-pore size and morphology of the graft walls were observed by SEM. The graft lumina were immobil ized with rF II. Twenty hybrid male dogs [weighing (20 ± 1) kg] were used for animal model of carotid artery defect and were randomly divided into 3 groups: rF II -immobil ized PU group, no rF II -immobil ized PU group and expanded polytetrafluoroethylene (ePTFE) group. The vascular grafts were implanted for repairing injured segments of carotid artery in dogs. The general health state of animals was recorded. At 30 days and 60 days,the patency rate of every group was calculated. At 60 days IDs were measured, cell prol iferation in neointima was inspected by l ight microscope, morphology on neointima was observed by SEM. Results The ID of the PU vascular grafts was (3.74 ± 0.06) mm, wall thickness was 0.4-0.6 mm, the wall density was 0.25 g/cm3, the porosity was 79.8%, racical compl iance was 8.57%/100 mmHg. In the wall, micropores were well distributed and opened-pores structure was observed. Pore size was (140 ± 41) μm in the outside layer, pore size was (100 ± 3) μm in the inside layer, thickness ratio of outside / inside layers was 2 ∶ 1, the pore size was (40 ± 16) μm on the lumina surface. After operation the wounds on neck healed, all the animals survived and had no compl ication. At 30 days and 60 days after implantation, the patency rate for rF II -immobil ized PU group were 100% and 66.7%, for no rF II -immobil ized PU group were 66.7% and 33.3%, and for ePTFE group were 67.7% and 0 respectively, but at 60 days there were thrombosis at anastamotic sites of some grafts occluded. Before operation the IDs for rF II-immobil ized PU group, no rF II -immobil ized PU group and ePTFE group were (3.74 ± 0.06), (3.74 ± 0.06) and (4.00 ± 0.03) mm, at 60 days after operation the IDs were (4.51 ± 0.05), (4.31 ± 0.24) and (4.43 ± 0.12) mm respectively, showing no statistically significant differences between 3 groups (P gt; 0.05). Histological inspection indicated that at 15 days a layer of plasma protein deposited on the lumina, at 30 days some cells adhered to the lumina, at 60 days neointima could be observed on the lumina. Thickness of the neointima became larger with implantation time. At 60 days neointima thickness at proximal end, middle site and distal end ofgraft were (560 ± 22), (78 ± 5) and (323 ± 31) μm respectively for rF II -immobil ized PU group. The results of SEM showed that neointima surface consisted of flat and long cells which long axes ranged with blood flow direction and was similar to lumina morphology of carotid artery of dog. Conclusion Immobil ization of rF II to lumina of grafts could enhance fibrinolytic activity and inhibited formation of thrombo-embol ia which led to an increase in patency rate after implantation.
Objective To analyze the quantitative relationship between respiratory effort and inferior vena cava (IVC) diameter variability in healthy adults, and explore the effects of respiratory effort on the fluid responsiveness with IVC diameter variability. Methods From October 2022 to May 2023, a cross-sectional study was conducted in healthy young subjects who met the criteria. Respiratory effort was evaluated by using portable pulmonary function to measure the subjects’ inspiratory conditions in three states (quiet breathing, moderate inspiration, and maximal inspiration). At the same time, the IVC internal diameter was measured by bedside ultrasound and the IVC diameter variability was calculated. The correlation between inspiratory volume and IVC diameter variation was analyzed, and the receiver operator characteristic (ROC) curve was drawn. The sensitivity and specificity of fluid responsiveness induced by inspiratory effort were predicted according to the area under the ROC curve (AUC). Results A total of 95 subjects were screened, aged 27.13±5.77 years, of whom 30 (32%) subjects were males. During quiet breathing, 41.1% of subjects had IVC inner diameter variation ≥50%. For moderate inspiration, it was 68.4%. At maximum inspiration, this proportion is more than 85%. Inspiratory volume was moderately positively correlated with IVC diameter variation, and the correlation coefficient r=0.45. With the IVC diameter variation ≥50% as the positive criterion for fluid responsiveness, the AUC of fluid responsiveness induced by inspiratory effort was 0.73 (95% confidence interval 0.67 - 0.78, P<0.001), and the inspiratory volume threshold was 13 mL/kg ideal body weight when the maximum Youden index was 0.41. That is, moderate force breathing can induce fluid responsiveness, with sensitivity of 79.57% and specificity of 61.62%. Conclusion The degree of respiratory effort significantly affects the IVC inner diameter variation, and there may be false positives in the evaluation of fluid responsiveness according to IVC inner diameter variation in the case of spontaneous breathing.
ObjectiveTo investigate the feasibility and effectiveness of using ultrasound to evaluate the internal mammary artery (IMA) and explore the related factors affecting the quality of IMA.MethodsFrom July 2020 to January 2021, for patients who underwent coronary artery bypass grafting at the Department of Cardiovascular Surgery, Fuwai Hospital, ultrasound was applied to measure bilateral IMA at the parasternal second intercostal space. There were 62 males and 18 females with an average age of 59.9±8.3 years. The clinical data of the patients were recorded and analyzed.ResultsA total of 160 IMA were measured. The IMA was detected in 99.4% (159/160), and the one that was not measured was proved to be occluded by enhanced CT. A total of 157 (98.1%) IMA intima were smooth, 2 (1.3%) were found to have uneven intimal thickening and less smooth, and only 1 (0.6%) was occluded. The intravascular diameter, peak systolic flow rate, peak diastolic flow rate, and blood flow rate of the left second intercostal IMA were 1.9±0.3 mm, 66.8±17.7 cm/s, 6.4 (0.0, 9.7) cm/s, 19.7±9.4 mL/min; and those of the right one were 2.1±0.3 mm, 69.7±18.5 cm/s, 6.0 (0.0, 9.2) cm/s and 22.8±11.5 mL/min, respectively. IMA vessel diameter and blood flow were greater on the right than those on the left side in the same individual (P<0.01). In univariate analysis, sex and body surface area were the factors that influenced the size of the IMA vessel among different individuals, and by linear regression analysis, the size of the IMA vessel was only related to body surface area among different individuals. On univariate analysis, diabetes mellitus was the only factor affecting IMA blood flow, with a mean reduction in blood flow of 18.4% (left) and 21.7% (right) in the diabetic group (P<0.05).ConclusionPreoperative evaluation of the IMA using ultrasound over the parasternal second intercostal space is easy, noninvasive, and has a high success rate. The internal diameter of the IMA is positively correlated with body surface area, and blood flow is significantly reduced in patients with diabetes.
Objective To analyze the effect of inner diameter of pancreatic duct following pancreaticoduodenectomy on pancreatic fistula. Methods From January 1995 to December 2008, 256 patients underwent pancreaticoduodenectomy were divided into four groups based on the types of pancreaticojejunostomy: end-to-side “mucosa-to-mucosa” anastomosis group (n=115), end-to-end “mucosa-to-mucosa” anastomosis group (n=71), end-to-end invaginated pancreaticojejunostomy group (n=43) and pancreaticogastrostomy group (n=27). Alternatively, 238 patients were divided into two groups according to drainage ways: stenting tube for internal drainage group (n=132) and stenting tube for external drainage group (n=106). Furthermore, 233 cases were divided into three groups on the basis of inner diameter of pancreatic duct: ≤0.2 cm group (n=54), 0.2-0.4 cm group (n=93) and ≥0.4 cm group (n=76). Then, the incidence rate of pancreatic fistula of each group was compared. Results The incidence of pancreatic fistula was 8.20% (21/256). The incidence of pancreatic fistula for different types of pancreaticojejunostomy was as follow: end-to-side “mucosa-to-mucosa” anastomosis group (7.83%， 9/115), end-to-end “mucosa-to-mucosa” anastomosis group (7.04%, 5/71), end-to-end pancreaticogastrostomy invaginated group (13.95%, 6/43) and pancreaticogastrostomy group (3.70%, 1/27), in which there wasn’t significant difference in 4 groups （χ2=2.763，P=0.430）. There was no significant difference of the incidence of pancreatic fistula between stenting tube for internal drainage group (9.10%, 12/132) and stenting tube for external drainage group (8.49%, 9/106), χ2=0.126, P=0.722. The incidence of pancreatic fistula in ≥0.4 cm group, 0.2-0.4 cm group and ≤0.2 cm group was respectively 0, 15.05% (14/93) and 11.11%(6/54), and the difference was significant (χ2=12.009, P=0.002). No correlation was found between the incidence of pancreatic fistula of different inner diameter of pancreatic duct and the types of pancreaticojejunostomy (χ2=1.878， P=0.598). Conclusion The inner diameter of pancreatic duct is an important factor for postoperative pancreatic fistula. No relationship is found between the types of pancreaticojejunostomy and pancreatic fistula in this study.
Objective To observe whether the adoptation of tricuspid annulus diameter as surgical indication for tricuspid annuloplasty will reduce the occurrence of moderate-severe tricuspid regurgitation(TR) in patients after mitral valve replacement (MVR). Methods Between April 2005 and June 2006, MVR was performed in 56 patients with no or mild TR in our Department. The patients were divided into two groups according to tricuspid annulus diameter(TAD)/body surface area (BSA)≥21mm/m2. Tricuspid annuloplasty group(TA group): 22 cases, male 8, female 14, age 45.0±7.7 years, TAD 36.8±3.8mm, BSA 1.57±0.15m2, New York Heart Association(NYHA) functional class Ⅲ/Ⅲ-Ⅳ 18/4, sinus rhythm(SR)/atrial fibrillation (AF) 2/20. Notricuspid annuloplasty group (NTA group): 34 cases, male 9, female 25, age 42.9±11.0 years, TAD 28.5±4.4mm, BSA 1.58±0.13m2, NYHA Ⅲ/Ⅲ-Ⅳ 28/6, SR/AF 9/25. Kay annuloplasty was performed for TA group patients. The patients were followed in outpatient clinical regularly and evaluated by echocardiography at 6 months after operation. Results All patients recovered and were discharged from hospital. The duration of follow-up was 11.0±2.4 months. Except 2 cases, all patients received echocardiography evaluation at 6 months after operation. There were no significantly differences between two groups patients in general clinical characteristics (Pgt;0.05). Compared with NTA group before operation, right atrial diameter (RAD, 49.3±7.0mm) and TAD(36.8±3.8mm) were bigger and more mild TR in TA group (Plt;0.05). RAD(44.1±8.9mm) and TAD(28.9±6.1mm) reduced and the proportion of TR degree improved (Plt;0.05) in TA group but did not occur in NTA group after surgery (Pgt;0.05). There were three cases of moderate TR in NTA group. Conclusion Tricuspid annuloplasty adopting TAD as surgical indication may reduce the occurrences of postoperative moderate-severe TR for patients of MVR with no or mild preoperative TR.
Objective To study the effect of preparation conditions for small-diameter polyurethane(PU) vascular graft on microstructure and mechanical properties. Methods The small-diameter microporous PU artificial vascular grafts were prepared by dipping and leaching method. The dimension and microstructure were controlled by changing mold diameter, PU materials, salt sizes, salt to polymer ratio, times of dipping layers etc. The mechanical properties of PU grafts including radical compliance, water permeability, longitudinal strength, burst strength, and suture tearing strength were measured and the effect of the graft dimension and microstructure on their properties were studied. Results The internal diameter of grafts prepared was 2-4 mm depending on mold diameter. The wall thickness was 0.6-1.2 mmafter dipping 4-8 layers. The density was 0.23-0.49 g/cm3. The pore was 42-95 μm in diameter. The porosity was 56%80%. The radical compliance was 1.2%-7.4%·13.3 kPa-1 and higher compliances could be obtained by using moreelastic polyurethane, higher salt to polymer ratio, longer diameter and less wall thickness. The water permeability, mainly depending on salt to polymer ratio,diameter, and wall thickness, was 0.29-12.44 g／(cm2·min). The longitudinal strength was 1.55-4.36 MPa correlating with tensile strength of polyurethane and salt to polymer ratio. The burst strength was 60-300 kPa also depending on tensile strength of polyurethane and salt to polymer ratio. The suture tearing strength was 19.5-96.2 N／cm2 depending on tensile strength of polyurethanebut not on the angle of tearing and graft axial directions. The compliance and water permeability of Chronoflex grafts were higher than those of PCU1500 grafts, but longitudinal strength, burst strength, and suture tearing strength of PCU1500 grafts were better than those of Chronoflex grafts. Conclusion Small-diameter grafts with proper pore sizes, porosity, matching compliance can be obtained by selecting PU materials and optimizing the preparation conditions.
ObjectiveTo detect the difference in the osteogenesis ability of biphasic calcium phosphate (BCP) ceramic granular materials with different mesoporous diameters prepared at different sintering temperatures through in vivo and in vitro experiments, so as to provide evidence for screening BCP materials with better clinical application parameters.MethodsThree kinds of BCP (materials 1, 2, 3) were prepared by mixing hydroxyapatite (HA) and β-tricalcium phosphate (β-TCP) at a ratio of 8∶2 and sintered at 1 050, 1 150, and 1 250℃ for 3 hours, respectively. The internal porosity and the diameter, volume, and area of the mesopore were measured by Brunauer-Emmett-Teller test (BET); the composition of the material was evaluated by X-ray diffraction (XRD); the microscopic surface morphology of the material was observed by scanning electron microscopy (SEM). The 3rd generation bone marrow mesenchymal stem cells (BMSCs) from Sprague-Dawley rats were co-cultured with the materials 1, 2, and 3 for 7 days in vitro respectively (groups A, B, and C), and the cells adhesion on the materials was observed by SEM and phalloidine staining, respectively. Cell proliferation activity was measured by cell counting kit 8 method. In vivo, 9 muscle bags were made in dorsal muscles of 9 beagles, respectively. The muscle bags were randomly divided into 3 groups (3 per beagle in each group) and materials 1, 2, and 3 were placed into the muscle bags of groups A, B, and C, respectively. After 1, 2, and 3 months of operation, 3 beagles were anesthetized and the samples were stained with HE, Masson, and Safranin, and the bone formation area ratio in the BCP gap was calculated. Real-time fluorescence quantitative PCR (qRT-PCR) was performed to detect the expressions of bone-related genes [including alkaline phosphatase (ALP), osteopontin (OPN), and osteocalcin (OC)].ResultsThe BET test showed that with the increase of sintering temperature, the internal porosity of the particles did not change significantly, but the diameter, volume, and area of the mesopores gradually decreased. The XRD detection showed that the XRD waves of HA and β-TCP could be seen in all 3 kinds of materials; SEM showed that there were widely distributed macropores on the surface of 3 kinds of BCPs, and the interpores connected with the others. In vitro, BMSCs adhered and proliferated on the surfaces of 3 kinds of BCPs, and the cell biocompatibility of the materials in groups B and C was better than that in group A. In vivo, obvious osteoid tissue deposition could be observed in the intergranular space of 3 kinds of BCPs from 2 months after implantation. The bone formation area ratio of each group increased with time. The bone formation area ratio in group A was significantly higher than that in groups B and C at 2 and 3 months after implantation, and in group A than in group B at 1 month (P<0.05). qRT-PCR showed that the expressions of osteogenic related genes peaked at 2 months in group A, and gradually increased with time in groups B and C. The relative expressions of ALP and OPN mRNAs in group A were significantly higher than those in groups B and C at 1 month after implantation, the relative expression of OC mRNA in group A was significantly higher than that in groups B and C at 2 months after operation, the relative expression of ALP mRNA in groups B and C and the relative expression of OPN mRNA in group B were significantly higher than those in group A, all showing significant differences (P<0.05); there was no significant difference in the relative expression of each gene among the other groups at each time point (P>0.05).ConclusionThe mesoporous diameter of BCP decreases with the increase of sintering temperature. Different mesoporous diameters lead to different ectopic osteogenesis of BCP materials. BCP material with mesoporous diameter of 12.57 nm has better osteogenic ability which can activate the osteogenic gene earlier. The mesoporous diameter is expected to be an adjustable index for optimizing the osteogenic capacity of BCP materials.
Research on the deposition of inhaled particles in human pulmonary acinus region is important to the pathogenesis investigation, prevention and treatment of lung diseases. Most of the current research focus on the final deposition fraction of inhaled particles in human acinar region, but little is involved in their dynamic deposition characteristics. In this paper, five multi-alveolar models, G3−G7, were built. The evaluation parameter 1/4 deposition time was introduced to study the particle deposition speed. The deposition characteristics of particles in the diameter ranging 0.1−5 μm were numerically simulated and summarized under the influence of factors such as the generation and structure of model, particle diameter and respiratory mode, shedding some new light on the further research of transport of inhaled particles. The results showed that the generation and structure of model had a significance effect on the deposition of particles. 0.1 μm particles were dominated by Brownian diffusion, which experienced a high deposition fraction, a fast deposition speed and a logarithmic deposition curve, while 5 μm particles were dominated by gravitational sedimentation, with a high deposition fraction, a fast deposition speed and an S-shaped deposition curve. The deposition of 0.3−1 μm particles were influenced greatly by convention and varied with the change of respiratory mode. The research methods and results in this paper can provide theoretical basis and data support for the further exploration of the mechanism, prevention and treatment of lung diseases.
The aim of the present experimental study is to determine the effects of sinotubular junction diameter on artificial bioprosthesis valves. An experimental study was performed for aortic root models with different sinotubular junction taper under pulsatile flow condition. The sinotubular junction diameters were modified to create four models with different sinotubular junction tapers with 0, 1, 3 and 5 degrees, respectively, using three dimensional printing techniques. After installing the testing bioprosthesis valve on the aortic root models, we conducted experiments of the pulsatile flow testing with different stroke volume in the pulsatile circulation simulation system. The testing condition was set at the pulse frequency of 70 beats/min and the stroke volume of 2–7 L/min. The status of the valves in 10 continuous pulse cycles was tested and the average results were obtained for each stroke volume. The results of testing showed that the mean transvalvular pressure gradients agreed well with the national standard, and all smaller than 10 mm Hg. The sinotubular junction taper had an influence on regurgitation fraction of the artificial bioprosthesis valve. The smaller sinotubular junction taper showed beneficial effect to decrease the regurgitation fraction. In the case of smaller stroke volume, the smaller sinotubular junction taper was beneficial to increase the effective valve orifice area. In the case of larger stroke volume, the larger sinotubular junction taper was beneficial to increase the effective valve orifice area. This study indicates that a doctor should consider the smaller sinotubular junction taper in the case of smaller stroke volume more. In the case of larger stroke volume, the doctor should consider the larger sinotubular junction taper more.