This study aims to explore the effect of aortic sinus diameter on aortic valve opening and closing performance in the case of no obvious disease of aortic valve and annulus and continuous dilation of aortic root. A total of 25 three-dimensional aortic root models with different aortic sinus and root diameters were constructed according to the size of clinical surgical guidance. The valve sinus diameter DS is set to 32, 36, 40, 44 and 48 mm, respectively, and the aortic root diameter DA is set to 26, 27, 28, 29 and 30 mm, respectively. Through the structural mechanics calculation with the finite element software, the maximum stress, valve orifice area, contact force and other parameters of the model are analyzed to evaluate the valve opening and closing performance under the dilated state. The study found that aortic valve stenosis occurs when the DS = 32 mm, DA = 26, 27 mm and DS = 36 mm, DA = 26 mm. Aortic regurgitation occurs when the DS = 32, 36 and 40 mm, DA = 30 mm and DS = 44, 48 mm, DA = 29, 30 mm. The other 15 models had normal valve movement. The results showed that the size of the aortic sinus affected the opening and closing performance of the aortic valve. The smaller sinus diameter adapted with the larger root diameter and the larger sinus diameter adapted with the smaller root diameter. When the sinus diameter is 40 mm, the mechanical performance of the valve are good and it can well adapt with the relatively large range of aortic root dilation.
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.
ObjectiveTo explore the risk factors for tracheal stenosis caused by tracheotomy or intubation.MethodsFrom July 2010 to July 2020, a total of 44 patients were suffered with tracheal stenosis caused by tracheotomy or intubation at the First Affiliated Hospital of Hunan Normal University as case group (n=44), and 34 patients were suffered tracheotomy or intubation without tracheal stenosis as control group (n=34). The clinical application of intratracheal tube cuff diameter was investigated by univariate comparison, ROC analysis and multivariate logistic regression analysis.ResultsUnivariate analysis showed intratracheal tube cuff diameter (C)/transverse diameter at the level of the clavicle >150%, intubation time>7d, tracheal intubations/tracheostomy ≥2, recurrent respiratory tract infections and replacement of tracheal tube≥ 2 were the influence factors of posttracheostomy tracheal stenosis (PTTS) and postintubation tracheal stenosis (PITS) (P<0.005). Multivariate Logistic regression analysis showed C/T>150% (OR=6.681, 95%CI: 1.164 - 38.363), intubation time>7d (OR=4.723, 95%CI: 1.413 - 15.779), tracheal intubations/tracheostomy ≥2 (OR=4.526, 95%CI: 1.133 - 18.083) and recurrent respiratory tract infections (OR=3.681, 95%CI: 1.177 - 11.513) were positively correlated with PTTS and PITS. The area under the ROC curve (AUC) of C/T>150% was 0.665 with the sensitivity of 0.364 and the specificity of 0.033 (95%CI: 0.555 - 0.775). AUC of intubation time>7 d was 0.717 with the sensitivity of 0.568 and the specificity of 0.133 (95%CI: 0.613 - 0.821). AUC of tracheal intubations/tracheostomy ≥2 was 0.683 with the sensitivity of 0.432 and the specificity of 0.067 (95%CI: 0.574 - 0.791). AUC of recurrent respiratory tract infections was 0.707 with the sensitivity of 0.614 and the specificity of 0.200 (95%CI: 0.603 - 0.811). However, there was no statistically significant difference C/T>150% and those clinical data in Z test (Z=0.839, P=0.402; Z=0.302, P=0.763; Z=0.751, P=0.453).ConclusionIntubation time>7 d, tracheal intubations/tracheostomy ≥2, recurrent respiratory tract infections, replacement of tracheal tube≥ 2 and C/T>150% are risk factors for PTTS and PITS.
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.
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.
ObjectiveTo analyze risk factors of early outcomes of mitral valvuloplasty (MVP)for the treatment of degenerative mitral regurgitation (DMR). MethodsClinical data of 132 DMR patients who underwent MVP in Fu Wai Hospital between January 1, 2011 and November 1, 2011 were retrospectively analyzed. A total of 114 patients (86.4%)were followed up after discharge with their mean age of 51.21±12.78 years, including 76 males (66.7%). Preoperative risk factors of early outcomes of MVP were analyzed. ResultsAmong those patients, there were 25 patients with atrial fibri-llation (AF)(21.9%). Preoperative ejection fraction was 63.88%±6.93%. Preoperative echocardiography showed left ventricular end-diastolic diameter (LVEDD)was 31.61±5.51 mm/m2. There were 66 patients (57.9%)with tricuspid regurg-itation, and 34 patients (29.8%)underwent concomitant tricuspid valvuloplasty including 10 patients (8.8%)who received tricuspid annuloplasty rings. Two patients died postoperatively, 2 patients underwent re-operation of mitral valve replacement or MVP respectively. Postoperative echocardiography showed moderate or severe mitral regurgitation in 15 patients. Preoperative risk factors of early outcomes of MVP included AF (36.8% vs. 18.9%, P=0.035), large LVEDD (34.02±3.76 mm/m2 vs. 31.15±5.68 mm/m2, P=0.042)and functional mitral regurgitation (15.8% vs. 1.1%, P=0.007). Multivariate analysis showed greater postoperative LVEDD reduction significantly lowered the incidence of postoperative events (HR 0.002, 95% CI < 0.001-0.570, P=0.031). ConclusionsEnlargement of the left ventricle is an independent preoperative risk factor for early outcomes of MVP for DMR patients. Greater postoperative LVEDD reduction significantly lowers the incidence of postoperative events.
Objective To evaluate the effectiveness of multiple small-diameter drilling decompression combined with hip arthroscopy for early oeteonecrosis of the femoral head (ONFH). Methods Between March 2010 and December 2013, 91 patients with early ONFH were treated with the operation of multiple small-diameter drilling decompression combined with hip arthroscopy in 39 cases (53 hips, group A) or with drilling decompression alone in 52 cases (74 hips, group B). The patients in 2 groups had obvious hip pain and limited motion before operation. There was no significant difference in gender, age, etiology, effected side, stage of osteonecrosis, and preoperative Harris score between 2 groups (P>0.05). Results All operations succeeded and all incisions healed by first intention. The operation time was significantly longer in group A [(73.3±10.6) minutes] than in group B [(41.5±7.2) minutes] (t=8.726, P=0.000). Temporary of sciatic nerve apraxia after operation occurred in 2 patients of group A, and no complication occurred in other patients. Patients were followed up 24-52 months (mean, 39.3 months) in group A and 24-48 months (mean, 34.6 months) in group B. At last follow-up, the Harris scores were 83.34±8.76 in group A and 76.61±9.22 in group B, showing significant differences when compared between 2 groups (t=–4.247, P=0.029) and when compared with preoperative values in 2 groups (t=–10.327, P=0.001; t=–8.216, P=0.008). X-ray films showed that the collapse of the femoral head was observed in 6 hips (1 hip at stage Ⅰand 5 hips at stage Ⅱ) in group A, and in 16 hips (4 hips at stageⅠand 12 hips at stage Ⅱ) in group B; and hip arthroplasty was performed. The total effective rates were 88.68% (47/53) in group A and 78.38% (58/74) in group B, respectively; showing significant difference between 2 groups (χ2=5.241, P=0.041). Conclusion Multiple small-diameter drilling decompression combined with hip arthroscopy is effective in pain relief, improvement of hip function, slowing-down the process of femoral head necrosis, delaying the need for total hip arthroplasty in patients with early ONFH.
ObjectiveTo establish the Z-score reference ranges of fetal arterial ductus (DA) inner diameter of normal fetus at 20 to 40 weeks’ gestation.MethodsA cross-sectional study was conducted in 781 normal singleton pregnancies with 20-40 weeks of gestation who underwent fetal echocardiography in the Third Affiliated Hospital of Henan University of Chinese Medicine from November 2018 to September 2019. The DA diameter, biparietal diameter (BPD), and femoral diaphysis length (FL) were measured and used to estimate gestational age (GA). With BPD, FL, and GA as independent variables and DA as dependent variables, linear regression analyses were conducted on the mean and standard deviation of each parameter to construct the best Z-score models.ResultsThe linear regression equations reflected strong positive correlations between the fetal biological growth parameter BPD, FL, GA, and fetal DA inner diameter. The heteroscedasticity of standard deviations was eliminated by the weighted regression of absolute stagger, and the best Z-score models were constructed. The linear regression equations of GA (week), BPD (mm), FL (mm), and DA inner diameter (mm) were as follows: Y=−2.661+0.217×GA, Y=−2.505+0.084×BPD, Y=−1.734+0.100×FL; the linear regression equations of GA (week), BPD (mm), FL (mm), and the standard deviation of DA inner diameter (mm) were as follows:Y=−0.273+0.025×GA, Y=−0.440+0.013×BPD, Y=−0.180+0.012×FL. According to the models, Z-score normal range reference values of fetal DA inner diameter were calculated.ConclusionsThere are good linear relationships between fetal DA inner diameter and GA, BPD and FL. The Z-score reference ranges of fetal DA diameter during mid- and late-pregnancy are constructed, which are helpful to quantitatively evaluate the normal development of fetal DA and provide a reference for clinical diagnosis of fetal DA abnormality.
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.
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.