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 evaluate the feasibility of X-ray guided access to the extrahepatic segment of the main portal vein (PV) to create a transjugular extrahepatic portacaval shunt (TEPS). Methods 5F pigtail catheter was inserted into the main PV as target catheter by percutaneous transhepatic path under ultrasound guidance. The RUPS-100 puncture system was inserted into the inferior vena cava (IVC) by transjugular path under ultrasound guidance. Fluency covered stent was deployed to create the extrahepatic portacaval shunt after puncturing the target catheter from the IVC under the X-ray guidance, then shunt venography was performed. Enhanced CT of the abdomen helped identify and quantify the patency of the shunt and the presence of hemoperitoneum. Results The extrahepatic portacaval shunts were created successfully by only 1 puncture in 6 pigs. No extravasation was observed in shunt venography. One pig died of anesthesia on the day of operation. The extrahepatic portacaval shunts were failed in 2 pigs 3 days after the operation (one was occluded and the other one was narrowed by 80%). The extrahepatic portacaval shunts were occluded 2 weeks after the operation in the remaining 3 pigs. The shunts were out of the liver and no hemoperitoneum was identified at necropsy in the 6 pigs. Conclusion TEPS is technically safe and feasible under the X-ray guidance.
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 explore the short- and mid-term efficacy of Castor single branch aortic stent combined with subclavian artery bypass grafting for the aortic arch lesions. MethodsA retrospective analysis of the clinical data of patients with proximal anchor zone insufficiency aortic arch lesions treated with Castor stent combined with carotid-subclavian bypass at the Department of Cardiac Surgery, Drum Tower Hospital, the Affiliated Hospital of Nanjing University Medical School from August 2020 to November 2023 was performed. ResultsA total of 22 patients were included, including 19 males and 3 females, with an average age of 56±16 years. There were 18 patients of aortic dissection and 4 patients of aortic arch tumors. The success rate of surgical technique was 100.0%, and the average postoperative hospital stay for patients was 10±4 days. The median follow-up time was 20 months. During the follow-up period, there were no major complications such as endoleak, paraplegia, cerebral infarction, renal insufficiency, etc., and all patients had no readmissions. ConclusionFor proximal anchor zone insufficiency aortic arch lesions, the treatment method of using a Castor stent branch placed in the left common carotid artery can effectively extend the anchor zone, avoid the huge trauma of open chest surgery, and achieve good short- and mid-term efficacy.
Coronary atherosclerotic heart disease is a serious threat to human life and health. In recent years, the main treatment for it is to implant the intravascular stent into the lesion to support blood vessels and reconstruct blood supply. However, a large number of experimental results showed that mechanical injury and anti-proliferative drugs caused great damage after stent implantation, and increased in-stent restenosis and late thrombosis risk. Thus, maintaining the integrity and normal function of the endothelium can significantly reduce the rate of thrombosis and restenosis. Stem cell mobilization, homing, differentiation and proliferation are the main mechanisms of endothelial repair after vascular stent implantation. Vascular factor and mechanical microenvironmental changes in implanted sites have a certain effect on re-endothelialization. In this paper, the process of injury caused by stent implantation, the repair mechanism after injury and its influencing factors are expounded in detail. And repairing strategies are analyzed and summarized. This review provides a reference for overcoming the in-stent restenosis, endothelialization delay and late thrombosis during the interventional treatment, as well as for designing drug-eluting and biodegradation stents.
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.
Objective To investigate the short and medium term results of Castor single branched stent combined with parallel stent technique in the reconstruction of two supra-aortic branches in total endovascular repair of aortic arch lesions. Methods The patients with aortic arch disease who were treated with single-branch stents combined with parallel stents for Z1 anchoring and total endovascular repair from April 2022 to August 2022 in the Department of Cardiovascular Surgery of the First Affiliated Hospital of University of Science and Technology of China were retrospectively included, and the perioperative and follow-up data of the patients were analyzed. ResultsThere were 4 males and 1 female with an average age of (46.2±18.6) years. This study included 1 patient of aortic arch aneurysm and 4 patients of acute non-A non-B aortic dissection. The success rate of surgical technique was 100.0%. The operative time was (132.3±45.1) min, the immediate postoperative isolation of lesions was satisfactory, and there were no adverse events and death in perioperative period. The follow-up time was 12-15 months. During the follow-up period, all patients survived without stent displacement, type Ⅰa endoleak, parallel stent stenosis and occlusion, or re-operation. Conclusion The short and medium term results of single branched stents combined with parallel stents in total endovascular repair of aortic arch diseases requiring Z1 anchoring is satisfactory.
With the development of radiologic intervention, the treatments of aortic dissection are getting more and more diversified. In recent years, Debakey Ⅲ and DebakeyⅠaortic dissection has been usually treated with endovascular graft exclusion, or combined surgical and endovascular treatment. It is therefore more important to evaluate the aorta and its complications after interventional treatments. Because multidetector-row computed tomography (MDCT) has advantages, such as short examination time, high spatial resolution, and simple operation, this modality has become a first choice of non-invasive methods for the follow-up of aortic diseases after the intervention. Now the MDCT presentations and their anatomic-pathologic features of aortic dissection after endovascular graft exclusion or combined surgical and endovascular treatment are reviewed in this article.
Objective To investigate the effectiveness of percutaneous transluminal renal artery stenting (PTRAS) in treating atherosclerotic renal artery stenosis (ARAS). Methods A total of 69 patients with severe ARAS were treated with PTRAS between January 2002 and December 2008. There were 47 males and 22 females with an average age of 66.2 years(range, 42-88 years), including 66 cases of unilateral ARAS (single functional kidney, 1 case) and 3 cases of bilateral ARAS. Renal angiography revealed that the degree of renal artery stenosis was 70%-99%. Concomitant diseases included hypertension (67 cases), atherosclerosis obl iterans (69 cases), coronary heart disease (34 cases), diabetes (44 cases), and hyperl ipidemia (36 cases). Blood pressure, serum creatinine (sCr), and patency of the renal artery were measured to assess the effectiveness of PTRAS after 12 months. Results The renal artery stent was successfully implanted in 68 patients and the technical success rate was 98.6%. One patient was converted to il io-renal bypass because of intra-operative acute renal artery occlusion. One patient died of heart failure at 6 months after PTRAS, and 1 patient was lost at 3 months after PTRAS. The other 66 patients were followed up 32 months on average (range, 13-60 months). The blood pressure decreased significantly at 1 month and gained a further decrease at 12 months after PTRAS when compared with the preoperative ones [systol ic blood pressure: (132 ± 24) mm Hg vs (163 ± 34) mm Hg, P lt; 0.05; diastol ic blood pressure: (78 ± 11) mm Hg vs (89 ± 17) mm Hg, P lt; 0.05; 1 mm Hg=0.133 kPa]. Hypertension was cured in 4 cases (6.3%), improved in 52 cases (81.2%), failure in 8 cases (12.5%), and the overall benefit rate was87.5%. The sCr level was stable after 12 months of PTRAS, showing no significant difference when compared with preoperative basel ine [(107.8 ± 35.4) μmol/L vs (104.1 ± 33.8) μmol/L, P gt; 0.05]. Renal function was improved in 9 cases (13.6%), stable in 48 cases (72.8%), deterioration in 9 cases (13.6%), and the overall benefit rate was 86.4%. Instent restenosis found in 2 patients (3.0%) at 12 months after operation. Conclusion PTRAS is a safe and effective method to treat ARAS. It can control the blood pressure and stabil ize the renal function in most ARAS patients. Long-term efficacy needs further investigation.
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.