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.
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.
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.
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 investigate the existence of persistent systemic inflammation (PSI) among patients with chronic obstructive pulmonary disease (COPD) in local areas, and identify the risk factors of PSI.MethodsA total of 150 patients with stable COPD and 70 non-smoking healthy individuals were enrolled in our study. The levels of interleukin-6 (IL-6), IL-18 and activin A in serum were detected. Pulmonary function was tested, and basic information of the candidates was acquired at the same time. All of the patients were followed-up at 6 months, 12 months and 24 months for two years. The value at the 95th percentile of the concentration of inflammation markers of non-smoking healthy samples was defined as the threshold value, also known as normal ceiling limit value. Existence of PSI was defined as the condition that two or more kinds of inflammation markers exceed the threshold at each follow-up visit. The COPD patients were categorized into three classes, in which there were respectively none, one and two or more kinds of inflammation markers with over-threshold values. Based on a 2-year followup, patients with two or more kinds of inflammation markers exceeding threshold values were classified as PSI subgroup, and patients without inflammation markers exceeding threshold values as never inflamed subgroup.ResultsThere were 22 patients (14.7%) had persistent systemic inflammation, whereas 60 patients (40.0%) did not show evidence of systemic inflammation. Single factor analysis of two subgroups showed that the patients in PSI subgroup had higher body mass index (BMI), higher smoking index, higher prior frequency of time to exacerbation, higher proportion of patients at high risk for recurrent acute exacerbation during 2-year followup, higher SGRQ total score, lower FEV1%pred and lower FEV1/FVC ratio significantly (all P<0.05). Higher BMI and higher risk of recurrent acute exacerbation were independent risk factors leading to PSI, of which the higher risk of recurrent acute exacerbation had a more important effect on PSI.ConclusionsSome COPD patients have PSI in this region, which may constitute a novel COPD phenotype (called systemic inflammatory phenotype). Higher BMI and higher risk of recurrent acute exacerbation are independent risk factors leading to PSI. Individualized treatment to prevent acute exacerbation and appropriate weight control may be a better intervention for these patients.
ObjectiveTo systematically evaluate the outcomes of drug-eluting balloon (DEB) in treating coronary artery in-stent restenosis (ISR) by using meta-analysis and trial sequential analysis (TSA). MethodsWe searched PubMed, EMbase, The Cochrane Library（Issue 4, 2016）, CNKI, CBM, VIP and WanFang Data to collect randomized controlled trials (RCTs) regarding the treatment of ISR by DEB from inception to April 2016. After two reviewers independently screened citations, extracted data and assessed the bias risk of included studies, we carried out meta-analysis and TSA analysis by using RevMan 5.3 version and TSA v0.9 respectively. ResultsA total of 10 RCTs involving 1909 patients were included. Seven-hundred and forty-seven patients were included with regard to the comparison between DEB and POBA, 1162 patients were recruited to compare DEB and drug-eluting stents (DES). The results of meta-analysis revealed that DEB was associated with decreased mortality (OR=0.36, 95%CI 0.14 to 0.93, P=0.04), compared with that of plain old balloon angioplasty (POBA). And TSA showed that cumulative Z-curve strode the conventional threshold value but not the TSA threshold value which suggested a false positive result of meta-analysis. In comparison with that of POBA, DEB had a lower incidence of target lesion revascularization (TLR) (OR=0.16, 95%CI 0.07 to 0.38, P＜0.01). And the result of TSA displayed that the cumulative Z-curve strode both the conventional and TSA threshold value which validated the result of meta-analysis. Besides, the results of meta-analysis showed that there were no significant differences in mortality (OR=0.84, 95%CI 0.41 to 1.72, P=0.63) and TLR (OR=1.55, 95%CI 0.76 to 3.16, P=0.22) between DEB and DES. However, the result of TSA revealed that the cumulative Z-curve did not strode both the conventional and TSA threshold value, and the included sample size less was than required information size which suggested that the reliability of the meta-analysis needed more studies to confirm. While the subgroup analysis of EES revealed that DEB had a higher incidence of TLR than that of DEB (OR=3.37, 95%CI 1.59 to 7.15, P＜0.01). And the result of TSA displayed that the cumulative Z-curve strode both the conventional and TSA threshold value which validated the result of meta-analysis. ConclusionCurrent evidence shows, EES is superior to DEB in decreasing the incidence of TLR in patients with ISR, while DEB is superior to POBA. However, the comparison of DEB and other strategies on reducing of mortality in patients with ISR still needed more studies to prove.
Objective To evaluate the effect of niti-alloy urethral stent on the prevention of urethrocutaneous fistula and urethral stricture in hypospadias repair. Methods From January 2001 to December 2004, niti-alloy urethral stents were applied to repair congenital hypospadias in 63 patients. Among 63 patients, 49( 19 cases of proximal hypospadias, 22 cases of penoscrotal hypospadias and 8 casesof perineoscrotal hypospadias) received one-stage surgical managements of urethral reconstruction, and 10 underwent postoperative fistular repairs and 4 received repeated urethral reconstruction because of urethral stricture after hypospadias repair. Results All patients gained healing by first intention without fistula or urethral stricture. The stents were left indwelling in the neourethra for 2 months to 3 months to prevent stricture. The longest indwelling period was about 1 year. No dysuria or other discomfort occurred during this period. Conclusion Niti-alloy urethral stent can effectively prevent the postoperative urethrocutaneous fistula and urethral stricture after hypospadias repair.
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.
ObjectiveTo assess whether expanding the landing zone of frozen elephant trunk (FET) increases the risk of spinal cord injury in patients with acute type A aortic dissection. MethodsPatients with acute type A aortic dissection who were treated in Guangdong Provincial People’s Hospital from 2017 to 2020 were collected. They were divided into two groups according to the landing zone of FET by the image diagnosis of postoperative chest X-ray or total aorta CT angiography, including a Th9 group which defined as below the eighth thoracic vertebral level, and a Th8 group which was defined as above or equal to the eighth thoracic vertebral level. Using the propensity score matching (PSM) method, the preoperative and intraoperative data of two groups were matched with a 1∶2 ratio. The prognosis of the two groups after PSM was analyzed. Results Before PSM, 573 patients were collected, including 58 patients in the Th9 group and 515 patients in the Th8 group. After PSM, 174 patients were collected, including 58 patients in the Th9 group (46 males and 12 females, with an average age of 47.91±9.92 years), and 116 patients in the Th8 group (93 males and 23 females, with an average age of 48.01±9.53 years). There were 8 patients of postoperative spinal cord injury in the two groups after PSM, including 5 (4.31%) patients in the Th8 group and 3 (5.17%) patients in the Th9 group (P=0.738). In the Th8 group, 2 patients had postoperative transient paresis and recovered spontaneously after symptomatic treatment, and 1 patient had postoperative paraplegia with cerebrospinal fluid drainage. After 3 days, the muscle strength of both lower limbs gradually recovered after treatment. There was no statistical difference in complications between the two groups (P＞0.05). ConclusionExpanding the landing zone of FET does not increase the risk of spinal cord injury in patients with acute type A aortic dissection. However, the sample size is limited, and in the future, multicenter large-scale sample size studies are still needed for verification
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.