Extended postoperative venous thromboembolism prophylaxis after bariatric surgery: a comparison of existing risk-stratification tools and 5-year MBSAQIP analysis

Predicting short-term thromboembolic risk following Roux-en-Y gastric bypass using supervised machine learning

BACKGROUND

Roux-en-Y gastric bypass (RYGB) is a widely recognized bariatric procedure that is particularly beneficial for patients with class III obesity. It aids in significant weight loss and improves obesity-related medical conditions. Despite its effectiveness, postoperative care still has challenges. Clinical evidence shows that venous thromboembolism (VTE) is a leading cause of 30-d morbidity and mortality after RYGB. Therefore, a clear unmet need exists for a tailored risk assessment tool for VTE in RYGB candidates.

AIM

To develop and internally validate a scoring system determining the individualized risk of 30-d VTE in patients undergoing RYGB.

METHODS

Using the 2016-2021 Metabolic and Bariatric Surgery Accreditation Quality Improvement Program, data from 6526 patients (body mass index ≥ 40 kg/m2) who underwent RYGB were analyzed. A backward elimination multivariate analysis identified predictors of VTE characterized by pulmonary embolism and/or deep venous thrombosis within 30 d of RYGB. The resultant risk scores were derived from the coefficients of statistically significant variables. The performance of the model was evaluated using receiver operating curves through 5-fold cross-validation.

RESULTS

Of the 26 initial variables, six predictors were identified. These included a history of chronic obstructive pulmonary disease with a regression coefficient (Coef) of 2.54 (P < 0.001), length of stay (Coef 0.08, P < 0.001), prior deep venous thrombosis (Coef 1.61, P < 0.001), hemoglobin A1c > 7% (Coef 1.19, P < 0.001), venous stasis history (Coef 1.43, P < 0.001), and preoperative anticoagulation use (Coef 1.24, P < 0.001). These variables were weighted according to their regression coefficients in an algorithm that was generated for the model predicting 30-d VTE risk post-RYGB. The risk model's area under the curve (AUC) was 0.79 [95% confidence interval (CI): 0.63-0.81], showing good discriminatory power, achieving a sensitivity of 0.60 and a specificity of 0.91. Without training, the same model performed satisfactorily in patients with laparoscopic sleeve gastrectomy with an AUC of 0.63 (95%CI: 0.62-0.64) and endoscopic sleeve gastroplasty with an AUC of 0.76 (95%CI: 0.75-0.78).

CONCLUSION

This simple risk model uses only six variables to assist clinicians in the preoperative risk stratification of RYGB patients, offering insights into factors that heighten the risk of VTE events.

Achieving durable compliance with venous thromboembolism prophylaxis in bariatric surgery: 3-year data from a major academic medical center

BACKGROUND

Metabolic and bariatric surgery (MBS) venous thromboembolism (VTE) prescribing practices vary widely. Our institutional VTE prophylaxis protocol has historically been unstandardized.

OBJECTIVES

To create a standardized MBS VTE prophylaxis protocol, track protocol compliance, and identify barriers to protocol compliance and address them with Plan-Do-Study-Act (PDSA) cycles.

SETTING

Single Metabolic and Bariatric Surgery Accreditation and Quality Improvement Program-accredited academic hospital.

METHODS

We conducted a retrospective study for all patients undergoing MBS (January 2019 to September 2022). A multidisciplinary group of bariatric clinicians reviewed literature and developed the following standardized VTE prophylaxis protocol: 5000 units preoperative subcutaneous (SC) heparin within 60 minutes of anesthesia induction and postoperative 40 mg SC low molecular weight heparin (LMWH) within 24 hours of surgery. This protocol was distributed to relevant clinical stakeholders. We assessed monthly compliance rates through chart review. Goal compliance was ≥90%. We identified sources of noncompliance and addressed them with PDSA methodology.

RESULTS

A total of 796 patients were included. Preoperative heparin administration increased from a mean of 47% (107/228) preintervention to 96% (545/568) postintervention (P < .0001), and postoperative LMWH administration increased from 71% (47/66) to 96% (573/597, P = .0002). These compliance rates were sustained for 3 years. Barriers to protocol noncompliance included order set timing errors (n = 45), surgeon error (n = 44), surgeon discretion (n = 40), and nursing error (n = 20). No change in bleeding or VTE rates was observed.

CONCLUSIONS

Developing a standardized VTE prophylaxis protocol, monitoring process measures, and engaging relevant stakeholders in PDSA cycles resulted in drastic and durable improvement in VTE prophylaxis compliance rates.