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.
ObjectiveThe aim of this current meta-analysis is to evaluate the efficacy and safety of selective surgery after colonic stenting versus emergency surgery for acute obstructive colorectal cancer.MethodsThe studies published from January 1, 2000 to July 31, 2018 were searched from Pubmed, Embase, Cochrane Library, CNKI, Wanfang database, and VIP database. RevMan 5.3 software was used for data analysis.ResultsA total of 21 studies were included in this meta-analysis. Compared to emergency surgery, selective surgery after colonic stenting had significant lower mortality rate [OR=0.44, 95% CI was (0.26, 0.73), P<0.05], permanent stoma rate [OR=0.46, 95% CI was (0.23, 0.94), P<0.05], complication rate [OR=0.47, 95% CI was (0.35, 0.63), P<0.05], and wound infection rate [OR=0.40, 95% CI was (0.25, 0.65), P<0.05）], but had significant higher primary anastomosis rate [OR=3.30, 95% CI was (2.47, 4.41), P<0.05] and laparoscopic surgery rate [OR=12.55, 95% CI was (3.64, 43.25), P<0.05]. But there was no significant differences between the two groups as to anastomotic leak rate [OR=0.86, 95% CI was (0.48, 1.55), P>0.05].ConclusionsSelective surgery after colonic stenting can be identified in a reduced incidence of mortality rate, complication rate, permanent stoma rate, and wound infection rate, and also can increase primary anastomosis rate and laparoscopic surgery rate. Thus, for acute obstructive colorectal cancer, selective surgery after colonic stenting is better than emergency surgery.
Objective-To apply self-pulmonary tissue flap to reconstruct esophagus directly or with alloy stent in this research. Methods Twenty-four dogs were divided into two groups, middle bronchus was ligated to prepare pulmonaryflap and incised, a 4 to 6 cm long and 1/2 to 2/3 perimeter defect was made in esophageal wall. Esophagus defect was repaired only with pulmonary flap (experimental group) and with pulmonary flap having self-expanded stent inside (control group). The gross appearance, histological apearance and barium X-ray films were observed at 2,4,6,8,10 and 12 weeks after operation. Results Two dogs died of anatomotic leak in experimental group, three dogs died of anatomotic leak and two dogs died of perforation of ulcer in control group. The growth of esophagus epithelium was observed from periphery area to central area after 8 to 10 weeks of operation. In pulmonary flap mass fibrous tissue proliferated and fibroblasts were active, but no necrosis occurred. Barium X-ray ofregenerated esophagus showed that mild stenosis and weakened peristalisis were observed in the middle of resophagus replacement, and that no obstruction, leakage, and dilation above anastomotic stoma occurred. Conclusion Pulmonary tissue flap can well support the mucosa crawl in the defect of esophagus. It is necessary to find a more suitable and satisfied stent for repairing segmental defect.
Central venous stenosis is a common complication following long-term dialysis catheter placement in dialysis patients. Generally, percutaneous angioplasty is the treatment of choice, and venous stent implantation should be considered in different situations. However, the venous stent migrating into right atrium is a rare but fatal complication. We presented a patient whose superior vena cava stents migrated into right atrium, resulting in acute tamponade, and exploratory thoracotomy was proceeded.
ObjectiveTo study the prevention and treatment of restenosis after the stent placement in the latest progress. MethodsThere were four methods including drug-eluting stents, intracavitary illuminate, drug therapy, and mesenchymal stem cells, which prevented or treatment restenosis after stent placement. ResultsAll the four methods could reduce the postoperative restenosis rate after interventional treatment. Many experimental study of prevention and treatment of restenosis had obvious effect, but clinical curative effect was not very satisfactory, because of a series of problems such as safety, animal models, experiment method, and so on. ConclusionThe multiple factors and links caused restenosis should be considered fully, and interrupting the links or factors as far as possible could control the occurrence or development effectively.
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.
To evaluate the fatigue behavior of nitinol stents, we used the finite element method to simulate the manufacture processes of nitinol stents, including expanding, annealing, crimping, and releasing procedure in applications of the clinical treatments. Meanwhile, we also studied the effect of the crown area dimension of stent on strain distribution. We then applied a fatigue diagram to investigate the fatigue characteristics of nitinol stents. The results showed that the maximum strain of all three stent structures, which had different crown area dimensions under vessel loads, located at the transition area between the crown and the strut, but comparable deformation appeared at the inner side of the crown area center. The cause of these results was that the difference of the area moment of inertia determined by the crown dimension induced the difference of strain distribution in stent structure. Moreover, it can be drawn from the fatigue diagrams that the fatigue performance got the best result when the crown area dimension equaled to the intermediate value. The above results proved that the fatigue property of nitinol stent had a close relationship with the dimension of stent crown area, but there was no positive correlation.
Objective To introduce the technique of esophageal intraluminal stenting and assess its effect on the prevention of development of stenosis in patients with esophageal burns. Methods Thirty-three patients were admitted less than 3 weeks after ingestion of caustic agents. The second-or third-degree injuries were confirmed by esophogoscopy in all cases, but one with esophageal perforation at admission. Esophageal stenting was performed in all patients and these stents were kept in place for 4 to 6 months. Results There was no death in the series. All patients had a normal intake of food after removal of the stents, and stricture was not found on barium swallow test. Follow-up from 1 to 60 months five cases developed esophageal stenosis from 2 to 3 months after extracting the stents. One of them responded to esophageal bougienage, the remaining 4 patients required esophageal reconstruction and took a normal diet postoperatively. The other 28 patients have a normal diet after the stent removal. Conclusion The esophageal intraluminal stenting is able to prevent the formation of stricture in the aftermath of esophageal burns and its effect will be enhanced plus administering isoniazid.
Objective To investigate the effect of implanting uncovered self-expandable metal stent for treatment of distal malignant biliary obstruction through endoscope. Methods The effect of therapy about implanting uncovered self-expandable metal stents to 16 patients who had unsectable malignant tumors companing with obstructive jaundice through endoscope was reviewed. Results Fifteen of the studied patients were implanted uncovered self-expandable metal stents successfully (94%), for their internal drainage were patent. At the seventh and fourteenth day after implantation, liver function and B-ultrasound were rechecked. Compared to the data before operation, total bilirubin, direct bilirubin and transaminase declined respectively (P＜0.01). And the diameter of the total biliary duct became shorter (P＜0.01). Six of them returned to the normal level in three weeks. Early adverse events (in seven days) included mild acute pancreatitis (one case) and acute cholangitis (one case). Mean survival and patency of drainage were 186.93 days (54 to 426 days) and 156 days (51 to 426 days) respectively. All of them, 3 cases occured obstruction of stents (20%). Conclusion Implantation of uncovered selfexpandable metal stent through endoscope is an ideal therapy for distal malignant biliary obstruction.
ObjectiveThis study was aimed to evaluate the clinical efficacy of mechanical thrombectomy using the AngioJet System for the treatment of lower extremity acute arterial embolism and thrombosis.MethodsThe clinical data of 20 patients with acute lower extremity arterial embolism and thrombosis admitted to the Department of Vascular Surgery in the People’s Hospital in Gansu Province where the author worked from September 2016 to March 2017, were retrospectively analyzed. All patients were treated with the AngioJet mechanical thrombectomy system. Clinical data of the patients were retrospectively collected. The clinical efficacy of AngioJet mechanical thrombectomy wasanalyzed.ResultsEighteen (90.0%) of the 20 patients successfully completed the mechanical thrombectomy by using the AngioJet System. The mean time for hospital stay and operation was (4.2±1.4) d and (1.3±0.4) h, respectively. The average doses of urokinase and heparin during operation were (35.80±12.30) ×104 U and (45.10±8.30) mg, respectively. Two patients received a complementary treatment of incision for removing the thrombus. Two patients received catheter-directed thrombolysis after the mechanical thrombectomy, 5 patients received bare-metal stent implantation after balloon expansion. Clinical success was in 16 cases. According to the Cooley standard, 10 patients were in excellent condition,6 in good condition, 2 in fair condition, and 2 in poor condition. There were 2 cases of distal arterial embolization,2 cases of antecardial discomfort of bradycardia, and 4 cases of bleeding at the puncture point, but no serious bleeding complications such as gastrointestinal and intracranial hemorrhage occurred. A total of 16 patients presented myoglobinuria during and after operation. All patients were followed up for 6–12 months. The results of ultrasound examination showed that the artery was patency in 15 cases. One patient died of myocardial infarction in 9 months after surgery,2 patients developed lower extremity ischemia symptoms again after surgery, and 2 patients had lower extremity ulcer caused by lower extremity ischemia symptoms. During the follow-up period, no lower limb necrosis, amputation, and death occurred in the remaining patients.ConclusionsThe AngioJet mechanical thrombectomy system is safe and effective. Combined with the use of catheter-directed thrombolysis and stent implantation, the AngioJet mechanical thrombectomy could lead to quick recovery of the perfusion of the lower extremity and improve the limb salvage rates, exhibiting excellent clinical value.