Effect Of Different Operative Timing After Self-expanding Metal Stent Implantation On Patients With Malignant Colorectal Obstruction

ObjectivesThe purpose of this study is to investigate the optimal time interval from Self-expandable metal stents(SEMS)placement to surgery and the risk factors for operative complications in patients with acute malignant colorectal obstruction.MethodsIn this single-center,retrospective comparative cohort study,a total of 64 patients are enrolled and allocation to the case group(SEMS placing time≤14 days)including 19 patients and the control group(SEMS placing time>14 days)including 45 patients with left-sided acute malignant colorectal obstruction treated with SEMS placement and subsequent surgery between January 2013 and September 2020.The primary outcome is to compare the difference of baseline information,conditions of patients during the operation and postoperative conditions between the two groups applied by Student t test and chi-square test.Secondary outcomes include mining potential risk factors of postoperative complications performed by Multiple logistic regression analysis.The propensity score matching(PSM)and super learner(SL)method were used to eliminate the multiple confounding factors of baseline data.21 samples were collected as the external validation set including 6 cases and 15 in the control group for verification.ResultsThere was significant difference between the two groups in intraoperative bleed loss(P=0.009),number of harvested lymph nodes(P=0.027),postoperative hospital stay(P=0.002),postoperative complications(P<0.001),stoma creation(P<0.001),primary anastomosis(P<0.001).After 1:3 propensity score matching,the differences between the 8confounding variables of the two groups were no statistically significant(P>0.05).Caliper was set as 0.2.multiple logistic regression analysis showed that the potential risk factor for postoperative complications was SEMS placing time(P=0.00162),and the value of RR was 0.109(95%CI:0.028-0.433).It indicated that SEMS placing time > 14 days was an independent protective factor for postoperative complications in bridge-to-surgery(BTS)setting.The area under the ROC curve(AUC)was 76.7% verified by external data.ConclusionsLong duration of SEMS placement(>14days)may not influence surgical difficulty and is recommended for reducing postoperative complications.