Objective To investigate the bleeding characteristic and influencing factors after bariatric surgery.

Methods The retrospective case-control study was conducted. The clinical data of 3 371 patients with obesity who underwent bariatric surgery in the First Affiliated Hospital of Nanjing Medical University from May 2010 to August 2021 were collected. There were 903 males and 2 468 females, aged 31(16‒65)years. Observation indicators: (1) occurrence, diagnosis and treatment of bleeding after bariatric surgery; (2) analysis of influencing factors for bleeding after bariatric surgery. (3) Follow-up. Follow-up was conducted through outpatient examinations, telephone interview or WeChat to detect total weight loss rate, resolution of hypertension and remission of type 2 diabetes of the patients with bleeding after bariatric surgery. The follow-up was up to August 2021. Measurement data with normal distribution were represented as Mean±SD. Measurement data with skewed distribution were represented as M(range). Count data were represented as absolute numbers or percentages, and comparison between groups was analyzed by the chi-square test. Ordinal data were analzyed by the non-parametric rank sum test. Univariate analysis was conducted using the corresponding statistical methods based on data type. The binary Logistic regression was used for multivariate analysis.

Results (1) Occurrence, diagnosis and treatment of bleeding after bariatric surgery. There were 27 of 3 371 patients diagnosed with postoperative bleeding, including 13 males and 14 females. There were 18 cases of abdominal bleeding and 9 cases of gastrointestinal bleeding. Among the 27 patients with postoperative bleeding, 8 cases were diagnosed with bleeding on the day after operation, 13 cases were diagnosed on the first day after operation, 4 casess were diagnosed on the second day, and 2 cases were diagnosed on the third day or later. Among the 27 patients with postoperative bleeding, 24 cases had tachycardia as the main clinical manifestation, 11 patients had abnormal abdominal drainage with the drainage volume as 300(range, 100‒600)mL, 6 cases had hematocheziain with the volume as 500(range, 120‒1 000)mL, 5 cases were manifested as hypotension, 3 cases had hematemesis with the volume as 300(range, 50‒800)mL, 2 cases had a significant decrease in hemoglobin on the first day after operation. One patient may have multiple clinical manifestations. Among the 27 patients with postoperative bleeding, 6 cases with abdominal bleeding received emergency laparotomy due to continuous increase of abdominal drainage or hemorrhagic shock, of which one patient died of heart failure after emergency reoperation. The time between primary and secondary operation was 13.5(range, 2.0‒45.0)hours, and the volume of blood accumulation was 1 000(range, 600‒7 000)mL. The bleeding sites were identified in 5 patients during reoperation, including 2 cases of staple line bleeding after sleeve gastrectomy, 1 case of lesser sac bleeding after Roux-en-Y gastric bypass, 1 case of short gastric vessel bleeding and 1 case of trocar site bleeding. One patient had no obvious active bleeding during reoperation. The remaining 12 cases of abdominal bleeding and 9 cases of gastrointestinal bleeding were treated by conservative therapy. The duration of bleeding lasted for (2.1±0.7)days. (2) Analysis of influencing factors for bleeding after bariatric surgery. Results of univariate analysis showed that gender, hypertension, type 2 diabetes, surgical type were the related factors that affected the bleeding after bariatric surgery (χ²=6.33, 42.16, 4.49, 14.09, P<0.05). Results of multivariate analysis indicated that surgical type was a independent factor affecting postoperative bleeding in patients undergoing bariatric surgery (odds ratio=1.69, 95% confidence interval as 1.18‒2.41, P<0.05). (3) Follow-up. All the 27 patients were followed up for 16(1‒62)months. Eighteen patients reached or exceeded the 12 months follow-up time point. The 1-year total weight loss rate was 36%±12%, the resolution proportion of hypertension was 8/11, and the complete remission proportion of type 2 diabetes was 6/7. Six patients reached or exceeded the 36 months follow-up time point. The 3-year total weight loss rate was 35%±12%, the resolution proportion of hypertension was 4/5, and the complete remission proportion of type 2 diabetes was 1/1.

Conclusions The incidence of post-operative bleeding after bariatric surgery is low. Tachycardia, abnormal abdominal drainage and hypotension have sentinel functions. Surgical type is a independent factor affecting bleeding after bariatric surgery.