电力隧道盾构段隧道管片宽度、衬砌组合型式及支架变优化

万家丽路电力隧道是长沙市第1条地下电力隧道。原设计采用盾构施工,标准环拼装。文章提出采用通用环代替标准环,并对管片宽度、衬砌组合型式及支架变进行了优化,研究成果可为类似工程提供技术参考。

高速铁路牵引变电所主变低压侧电缆头支架方式的探讨

总结高速铁路牵引变电所近年来主变低压侧电缆头支架的几种方式,对各种主变低压侧电缆头支架方式进行了分析、比较,总 结各种主变低压侧电缆头支架的优缺点。

Control over Surrounding Rocks Deformation of Soft Floor and Whole-Coal Gateways with Trapezoidal Supports

In Gengcun Colliery, Yima Coal Group Co. Ltd.the characteristics of the gateways of thick coal seam and the coal seam is with fully mechanized sublevel caving mining are that the thickness of roof coal seam of gateways is larger, their surrounding rocks are the whole-coal mass and the coal seam is prone to Spontaneous Combustion. With the natural equilibrium arch theory, the reasonable adjacent distance of No.11 mine-type metal supports was calculated in trapezoidal gateways based on these characteristics. Then, in-situ supporting experiments were carried out. The results indicate that under the action of virgin rock stress, the width of broken rocks zone of surrounding rocks is 1.7–2.0 m in return heading and 1.1–1.3 m in going headway. And their surrounding rocks belong to the Ⅳ-type soften rock and the Ⅲ-type common surrounding rock respectively. Therefore, under the movable abutment pressure, the gateways deformation is serious. It is suggested that the designed gateways have to use pre-broadened cross section to suit their deformation. At the same time, the accumulated water on gateway floor must be drained in time. These measures were taken in the 1302 and 1304 coal faces in Gengcun Colliery, and the satisfactory results have been obtained.

Cutting-balloon angioplasty before drug-eluting stent implantation for the treatment of severely calcified coronary lesions

Background Severely calcified coronary lesions respond poorly to balloon angioplasty, resulting in incomplete and asymmetrical stent expansion. Therefore, adequate plaque modification prior to drug-eluting stent （DES） implantation is the key for calcified lesion treat- ment. This study was to evaluate the safety and efficacy of cutting balloon angioplasty for severely calcified coronary lesions. Methods Ninety-two consecutive patients with severely calcified lesions （defined as calcium arc 〉 180% calcium length ratio 〉 0.5） treated with bal- loon dilatation before DES implantation were randomly divided into two groups based on the balloon type： 45 patients in the conventional balloon angioplasty （BA） group and 47 patients in the cutting balloon angioplasty （CB） group. Seven cases in BA group did not satisfactorily achieve dilatation and were transferred into the CB group. Intravascular ultrasound （IVUS） was performed before balloon dilatation and after stent implantation to obtain qualitative and quantitative lesion characteristics and evaluate the stent, including minimum lumen cross-sectional area （CSA）, calcified arc and length, minimum stent CSA, stent apposition, stent symmetry, stent expansion, vessel dissection, and branch vessel jail. In-hospital, 1-month, and 6-month major adverse cardiac events （MACE） were reported. Results There were no statistical differences in clinical characteristics between the two groups, including calcium arc （222.2° ± 22.2° vs. 235.0° ± 22.1 °, p=0.570）, calcium length ratio （0.67 ± 0.06 vs. 0.77± 0.05, P = 0.130）, and minimum lumen CSA before PCI （2.59 ±0.08 mm2 vs. 2.52 ± 0.08 mm2, P = 0.550）. After stent implantation, the final minimum stent CSA （6.26 ± 0.40 mm2 vs. 5.03 ± 0.33 mm2; P = 0.031） and acute lumen gain （3.74 ±0.38 mm2 w. 2.44 ± 0.29 mm2, P = 0.015） were significantly larger ila the CB group than that of the BA group. There were not statis tically differences in stent expansion, stent symmetry, incomplete stent apposition, vessel dissection and branch vessel jail between two groups. The 30-day and 6-month MACE rates were also not different. Conclusions Cutting balloon angioplasty before DES implantation in severely calcified lesions appears to be more efficacies including significantly larger final stent CSA and larger acute lumen gain, without increasing complications during operations and the MACE rate in 6-month.

Prolonged high-pressure balloon angioplasty of femoropopliteal lesions：Impact on stent implantation rate and mid-term outcome

Objectives To assess the impact on stent implantation rate and mid-term outcomes of prolonged high pressure angioplasty of femoropopliteal lesions. Methods We retrospectively enrolled 620 consecutive patients from January 2011 to December 2011 （75.6 ±12.3 years, 355 males, 76.5%in Rutherford class 5-6）, referred for critical limb ischemia and submitted to prolonged high-pressure angioplasty of femoropopliteal lesions. The definition of prolonged high-pressure angioplasty includes dilation to at least 18 atm for at least 120 s. Proce-dural data, and clinical and instrumental follow-up were analyzed to assess stent implantation rate and mid-term outcomes. Results The preferred approach was ipsilateral femoral antegrade in 433/620 patients （69.7%） and contralateral cross-over in 164/620 （26.4%） and pop-liteal retrograde＋femoral antegrade in 23/620 （3.7%）. Techniques included subintimal angioplasty in 427/620 patients （68.8%） and endolu-minal angioplasty in 193/620 patients （31.2%）. The prolonged high pressure balloon angioplasty procedure was successful in 86.2%（minor intra-procedural complications rate 15.7%）, stent implantation was performed in 74 patients （11.9%）, with a significant improvement of ankle-brachial index （0.29 ±0.6 vs. 0.88 ±0.3, P〈0.01） and Rutherford class （5.3 ±0.8 vs. 0.7 ±1.9, P〈0.01）, a primary patency rate of 86.7%, restenosis of 18.6%on Doppler ultrasound and a target lesion revascularization of 14.8%at a mean follow-up of 18.1 ±6.4 months （range 1-24 months）. Secondary patency rate was 87.7%. Conclusions Prolonged high pressure angioplasty of femoropopliteal lesions appears to be safe and effective allowing for an acceptable patency and restenosis rates on mid-term.

Performance of dual-source CT with high pitch spiral mode for coronary stent patency compared with invasive coronary angiography

Objective To investigate the performance of dual-source computed tomography （DSCT） using high-pitch spiral fliPS） mode for coronary stents patency. Methods We conducted a prospective study on 120 patients with 260 previous stents implanted due to recurred suspicious symptoms of angina scheduled for invasive coronary angiography （ICA）, while DSCT were conducted using HPS mode. Results There was no significant impact of age, body mass index or heat rate （HR） on image quality （P 〉 0.05）, while HR variability had a slight impact on that （P 〈 0.05）. Sensitivity, specificity, positive predictive value （PPV）, negative predictive value （NPV） of DSCT in detection of in-stent restenosis （ISR） based per-patient were 92.3%, 96.7%, 88.9%, and 97.8%, respectively. And those based per-stent were 87%, 96.8%, 83.3%, and 97.7% with un-assessment stents, 97.4%, 99.5%, 97.4%, and 99.5% without un-assessment stents. There was significant differ- ence on sensitivity, specificity, PPV and NPV between diameter 〉 3.0 mm group （93.3%, 97.9%, 87.5%, and 98.9%） and diameter 〈 3.0 mm group （80%, 93.3%, 80.0%, and 93.3%） （P 〈 0.05）, and that between stent number 〉 3 group （82.3%, 77.8%, 66.7%, and 60%） with 〈 3 group （97.3%, 80%, 96.5%, and 75%）. The effective dose of DSCT （1.4 ± 0.5 mSv） is significantly less than that by invasive coronary angiography [4.0 ± 0.8 mSv （P 〈 0.01）]. Conclusion DSCT using HPS mode provides good diagnostic performance on stent patency with lower effective dose in patients with HR 〈 65 beats/rain.

Transradial versus transfemoral rotablation for heavily calcified coronary lesions in contemporary drug-eluting stent era

Background Although radial access for drug-eluting stent （DES） combined with rotational atherectomy （RA） in patients with calcified coronary lesions may be associated with a lower risk of major bleeding complications and obtain favorable clinical results compared with femoral access, the long-term outcome data of this approach were limited in contemporary DES era. Methods ＆ Results This retrospective study sought to compare in-hospital and long-term outcomes for patients undergoing RA via the transradial （TR） and transfemoral （TF） route in 126 consecutive patients （59 radial, 67 femoral） from 2009 to 2014. TR RA procedures were performed in 44/62 （71%） by the three TR operators, compared with 15/64 （23%） by the four TF operators in the present study. Significantly smaller diameter guide catheters and burrs （1.39 ± 0.16 mm vs. 1.53 ± 0.24 mm, P = 0.001） were used in the TR group. Procedural success rates were similar in both TR and TF groups. There was a significantly less major access site bleeding complications in favor of radial artery access （2% vs. 16%, P = 0.012）. The incidence of in-hospital death or myocardial infarction was low in both groups. Although a trend of lower adverse event rate was demonstrated in the TR group compared with the TF one, no statistical significance （21% vs. 27%, P = 0.135） was detected. Conclusions Radial access, a useful alternative to femoral access for RA and DES, can be safely and successfully performed on up to 71% of the patients with heavily calcified coronary lesions needing RA by experienced TR operators.

Cell Area and Strut Distribution Changes of Bent Coronary Stents:A Finite Element Analysis

Coronary stents are metal coils or mesh tubes delivered to blocked vessels through catheters, whic Recently, special drugs h are expanded by balloons to reopen and scaffold target vessels. are carried by stents （drug-eluting stents） to further reduce instent restenosis rate after stenting procedure. However, continual study on biomechanical characteristics of stents is necessary provide a more suitable drug loading for better interactions between stents and tissue, or to platform for drug-eluting stents. The purpose of this paper is to show how finite element methods can be used to study cell area and strut distribution changes of bent coronary stents. A same bending deformation was applied to two commercial coronary stent models by a rigid curved vessel. Results show that the stent design influenced the changes of cell area and strut distribution under bending situation. The stent with links had more cell area changes at outer curvature, and the stent with peak-peak （ 〉 〈 ） strut design could have strut contact and overlapping at inner curvature. In conclusion, this finite element method can be used to study and compare cell area and strut distribution changes of bent stents, and to provide a convenient tool for designers in testing and improving biomechanical characteristics of new stents.