Missing data represent a general problem in many scientific fields, especially in medical survival analysis. Dealing with censored data, interpolation method is one of important methods. However, most of the interpolation methods replace the censored data with the exact data, which will distort the real distribution of the censored data and reduce the probability of the real data falling into the interpolation data. In order to solve this problem, we in this paper propose a nonparametric method of estimating the survival function of right-censored and interval-censored data and compare its performance to SC (self-consistent) algorithm. Comparing to the average interpolation and the nearest neighbor interpolation method, the proposed method in this paper replaces the right-censored data with the interval-censored data, and greatly improves the probability of the real data falling into imputation interval. Then it bases on the empirical distribution theory to estimate the survival function of right-censored and interval-censored data. The results of numerical examples and a real breast cancer data set demonstrated that the proposed method had higher accuracy and better robustness for the different proportion of the censored data. This paper provides a good method to compare the clinical treatments performance with estimation of the survival data of the patients. This provides some help to the medical survival data analysis.
We had performed transjugular intrahepatic portosystemic stent shunt (TIPSS) in one hundred and three patients with advanced liver cirrhosis and portal hypertension from July,1993 to January, 1995. TIPSS was carried out successfully in ninty-eight out of 103 cases and the technical success rate was 95.2%. Acute variceal bleeding was immediatly controlled and portal pressure reduced by an average of 1.36±0.02 kPa after TIPSS. The disappearance of gastric cornoary and esophageal varices, the shrinkage of spleen and the reduction of ascite were observed . Three patients died of acute liver failure and one died of variceal redbleeding within 30 days of treatment. Mild encephalohthy was obserbed in 10 cases with TIPSS. At follow-up of 1～22 months, variceal rebleeding and ascite were observed in 6 patients and stenosis of shunt was evident is 12.5% of cases by the subsequent doppler sonography. According to this result, TIPSS is an effective method for the treatment of portal hypertension.
Abstract： The first generation scaffolds of bare metal stents （BMS） and the second generation of drug eluting stents （DES） have been widely used in the treatment of coronary heart diseases. However, long term incidences of major adverse cardiovascular events and revascularization treatments are still high because of in-stent re-stenosis and thrombosis. These may be caused by chronic inflammations and vascular wall damages due to persistent metal stents stimulation. What’s more, the eluting drugs within metal stents could also disturb normal growth of vascular endothelial cell, intima, tunica media, smooth muscle and epimysium. Therefore, in order to meet these demands several fully biodegradable scaffolds and drug carried stents have been manufactured using polymers polyester, polycarbonate and polyphosphate, etc. Among them, the security and histo-and hemo-compatibilities of coronary scaffolds made from poly-lactic acid （PLA）, poly-glycolic acid（PGA）, chitosan as coating, poly-caprolactone （PCL） and other copolymer like poly-lactic-co-glycolic acid （PLGA） have been testified to be sound. Nevertheless, there exist several different shortages for these stents such as tensile strength deficiency and slow degradation. PLA is hard and brittle with slow degradation, while PGA is soft with insufficient support force and fast degradation. Whether stents degrade too fast or too slow, they could not supply sufficient strength and effective support after implantation, and also they may cause target vascular injuries and elastic shrink inducing restenosis and thrombosis in long terms. Using optimized molar ratio component of PLA and PGA with chitosan coating, we can get sound composite materials with better biocompatibility, moderate degradation （approximately 3 - 6 months of completedegradation）, adequate mechanical strength, lower inflammatory response and good range of extension, and establish an experiment ground for fully biodegradable vascular scaffolds fabrication.
ObjectiveTo explore the relationship between blood glucose variability index and persistent organ failure (POF) in acute pancreatitis (AP). MethodsWe prospectively included those patients who were diagnosed with AP with hyperglycemia and were hospitalized in the West China Center of Excellence for Pancreatitis of West China Hospital of Sichuan University from July 2019 to November 2021. The patients were given blood glucose monitoring at least 4 times a day for at least 3 consecutive days. The predictive value of blood glucose variability index for POF in patients with AP was analyzed. ResultsA total of 559 patients with AP were included, including 95 cases of POF. Comparing with those without POF, patients with AP complicated by POF had higher levels of admission glucose (11.0 mmol/L vs. 9.6 mmol/L), minimum blood glucose (6.8 mmol/L vs. 5.8 mmol/L), mean blood glucose (9.6 mmol/L vs. 8.7 mmol/L), and lower level of coefficient of variation of blood glucose (16.6 % vs. 19.0 %), P<0.05. Logistic regression analyses after adjustment for confounding factors showed that the risk of POF increased with the increase of admission glucose [OR=1.11, 95%CI (1.04, 1.19), P=0.002], minimum blood glucose [OR=1.28, 95%CI (1.10, 1.48), P=0.001] and mean blood glucose [OR=1.18, 95%CI (1.04, 1.33), P=0.010]; with the higher level of coefficient of variation of blood glucose [OR=0.95, 95%CI (0.92, 0.99), P=0.021], the risk of POF decreased. The results of area under the curve (AUC) of the receiver operator curves showed that AG [AUC=0.787, 95%CI (0.735, 0.840)] had the highest accuracy in predicting POF, with sensitivities of 60.0% and specificities of 84.7%. ConclusionHigh admission glucose, minimum blood glucose, mean blood glucose, and low coefficient of variation of blood glucose were risk factors for the development of POF in patients with hyperglycemic AP on admission.
摘要:目的:探讨基层医院开展急诊经皮冠状动脉支架植入术(PCI)治疗急性心肌梗死(AMI)的可行性、安全性。方法:回顾分析2002年11月~2009年4月我院41例AMI患者的急诊PCI资料。结果:41例AMI患者,急诊开通梗死相关动脉(IRA)39例(即时成功率95.1%),开通IRA者中术后死亡2例(死亡率4.9%),总成功率90.2％。结论:在有条件的基层医院开展急诊PCI安全有效。Abstract: Objective: To explore the feasibility and safety of primary percutaneous coronary intervention in patients with acute myocardial infarction in elementary hospital. Methods: The clinical data of 41 AMI patients who underwent emergent PCI from November 2002 to April 2009 were retrospectively analyzed. Results: Among the 41 AMI patients referred to PCI, infarctrelated arteries were recanalized in 39 cases. The immediate success rate was 95.1%. 2 cases of them died. The total success rate was 90.2%.Conclusion: Emergent PCI is safe and effective in the hospitals which could carry out PCI.
The interventional therapy of vascular stent implantation is a popular treatment method for cardiovascular stenosis and blockage. However, traditional stent manufacturing methods such as laser cutting are complex and cannot easily manufacture complex structures such as bifurcated stents, while three-dimensional (3D) printing technology provides a new method for manufacturing stents with complex structure and personalized designs. In this paper, a cardiovascular stent was designed, and printed using selective laser melting technology and 316L stainless steel powder of 0−10 µm size. Electrolytic polishing was performed to improve the surface quality of the printed vascular stent, and the expansion behavior of the polished stent was assessed by balloon inflation. The results showed that the newly designed cardiovascular stent could be manufactured by 3D printing technology. Electrolytic polishing removed the attached powder and reduced the surface roughness Ra from 1.36 µm to 0.82 µm. The axial shortening rate of the polished bracket was 4.23% when the outside diameter was expanded from 2.42 mm to 3.63 mm under the pressure of the balloon, and the radial rebound rate was 2.48% after unloading. The radial force of polished stent was 8.32 N. The 3D printed vascular stent can remove the surface powder through electrolytic polishing to improve the surface quality, and show good dilatation performance and radial support performance, which provides a reference for the practical application of 3D printed vascular stent.
ObjectiveTo summarize the various treatment methods for reducing jaundice in the elderly patients with malignant obstructive jaundice (MOJ), and provide reference for the treatment of elderly MOJ.MethodUsing “malignant obstructive jaundice” as the Chinese keyword and the English keyword, a computer search of the literatures on the treatment of elderly MOJ patients was conducted and reviewed.ResultsThe treatment methods of reducing jaundice in elderly MOJ included radical surgery, cholangiojejunostomy, endoscopic ultrasound-guided biliary drainage, endoscopic biliary stent implantation, percutaneous transhepatic biliary drainage and stent implantation. Radical surgery was the most effective, but it was traumatic and had many complications for elderly patients. Cholangiojejunostomy was effective and suitable for elderly patients who cannot tolerate major surgery. Endoscopic ultrasound-guided biliary drainage was less traumatic to elderly patients, but technical difficulty. Endoscopic biliary stent implantation was currently the first-line choice for the treatment of elderly patients with advanced MOJ. Percutaneous transhepatic biliary drainage and stent implantation were suitable for elderly and frail patients with high obstruction.ConclusionThe treatment of elderly MOJ needs to be individualized and regionalized, and appropriate treatment methods should be selected according to the patient’s condition and the medical level of the medical center.
ObjectiveTo evaluate the clinical results of the self-manufactured screw director of the calcaneous sustentaculum tali in the surgical treatment of intra-articular calcaneal fractures. MethodsBetween May 2012 and October 2013, 40 patients (47 feet) underwent surgical treatment of intra-articular calcaneal fractures, and the clinical data were analyzed. There were 29 males and 11 females with an average age of 46 years (range, 25-68 years). According to Sanders classification, 17 feet were rated as type Ⅱ, 20 feet as type Ⅲ, and 10 feet as type IV. The average time from injury to admission was 6.02 hours (range, 1-12 hours). All the patients were treated with the screw director of the calcaneous sustentaculum tali to fix the sustentaculum tali. The intraoperative times of fluoroscopy were recorded. The Böhler angle and Gissane angle were measured at pre- and post-operation. The clinical functional outcomes were evaluated according to the Maryland foot score system. ResultsThe intraoperative times of fluoroscopy were 2-4 times (mean, 2.85 times). Radiographic examination showed 45 screws were accurately implanted into the middle of the sustentaculum tali in implanted 47 screws except 1 screw which penetrated into the anteroinferior of the sustentaculum tali and 1 screw which penetrated into the anterior of the sustentaculum tali. The accurate rate of screw implant was 95.7%. All patients were followed up for an average of 12 months (range, 8-18 months). During the follow-up, incision skin necrosis and infection occurred in 2 cases, and sural nerve injury developed in 3 cases. Bone union was achieved at an average of 12.72 weeks (range, 9-18 weeks) postoperatively. The Böhler angle was improved significantly from (6.48±3.67)° pre-operatively to (29.40±4.65)° post-operatively (t=-31.38, P=0.00). The Gissane angle was improved significantly from (99.30±5.85)° pre-operatively to (130.84±5.08)° post-operatively (t=-28.32, P=0.00). The Maryland foot score was 90.66 on average (range, 65-98) at last follow-up; the results were excellent in 41 feet, good in 3 feet, and fair in 3 feet with an excellent and good rate of 93.6%. ConclusionThe self-manufactured screw director of the calcaneous sustentaculum tali can significantly improve the accuracy of the screw implanted into the sustentaculum tali and reduce the harm of intraoperative fluoroscopy to the body.
ObjectiveTo analyze the main points and advantages of covered endovascular reconstruction of aortic bifurcation (CERAB) technique in the treatment of complex aortic and iliac artery lesions. MethodThe data of the patient with bilateral common iliac artery stenosis and lower abdominal aortic calcification treated by CERAB technology in the Department of Vascular Surgery of West China Hospital of Sichuan University and the technology in combination with the characteristics of balloon-expandable covered stent were analyzed. ResultsThe lesions were successfully treated by CERAB technique. The stents of bilateral iliac arteries were in perfect shape and good adherence. The radiography of the abdominal aorta and bilateral internal and external iliac arteries were well displayed. ConclusionsFrom analysis results of this case, CERAB technology is effective and feasible in treatment of lesions at the bifurcation of the main aortic and iliac artery. The shape of aortic bifurcation is satisfactorily recovered. The key point for the successful implementation of this technology is balloon-expandable covered stent.
Objective To compare the early compl ications of carotid stenting (CAS) and carotid endarterectomy (CEA) in treatment of carotid artery stenosis. Methods Between January 2005 and December 2007, 63 patients with carotid artery stenosis were treated with CEA in 36 cases (CEA group) and with CAS in 27 cases (CAS group). There were 42 males and 21 females with an average age of 67.5 years (range, 52-79 years). The locations were the left side in 28 cases and the rightside in 35 cases. The carotid stenosis was 60%-95% (mean, 79%). The major cl inical symptoms were stroke and transient ischemic attack. The cranial CT showed old cerebral infarction in 24 cases, lacunar infarction in 22 cases, and no obvious abnormal change in 17 cases. The encephalon, heart, and local compl ications were compared between 2 groups within 7 days after operation. Results In CEA group, encephalon compl ications occurred in 3 cases (8.3%), heart compl ications in 2 cases (5.6%), and local compl ications in 5 cases (13.9%); while in CAS group, encephalon compl ications occurred in 8 cases (29.6%), heart compl ications in 1 case (3.7%), and local compl ications in 3 cases (11.1%). The encephalon compl ication ratio of CAS group was significantly higher than that of CEA group (χ2=4.855, P=0.028); and there was no significant difference in other compl ications ratios between 2 groups (P gt; 0.05). Conclusion CEA is the first choice to treat carotid artery stenosis.