Emergency Surgery Increases Risk of Venous Thromboembolism

Samuel Ross, MD, MPH

Emergency surgery and increased invasiveness were independently associated with venous thromboembolism compared with elective surgery, according to new study findings.

Samuel Ross, MD, MPH, and a team of US-based investigators used the American College of Surgeons National Surgical Quality Improvement Program database to learn whether emergency case status was independently associated with VTE compared with elective case status. The team also tested the hypothesis that emergency cases would have a higher risk of VTE.

Ross, from the surgery department at Carolinas Medical Center, and the investigators found that those who underwent emergency general surgery had almost twice the risk for VTE than those who had elective surgery, which the team reported was previously unknown.

The team used the database from January 2005-December 2016 to compare the rates of VTE in 3 of the most common operations: cholecystectomies, ventral hernia repairs, and partial colectomies. The database included >800 hospitals and >250 variables from each participant. Information was available for colorectal, pancreatic, and hysterectomy procedures.

Patients were identified by either laparoscopic or open variant codes based on their procedure.

The investigators conducted a multivariable analysis that controlled for age; sex; body mass index; bleeding disorder; disseminated cancer; laparoscopy approach; and surgery type.

A data abstractor collected data on preoperative demographics; comorbidities; laboratory values; operative and postoperative details; 30-day complications and mortality; and disposition.

The primary outcome was VTE, which was measured as an aggregate of the variables of deep vein thrombosis and pulmonary embolism. Additional measures included time to diagnosis of deep vein thrombosis and pulmonary embolism, respiration, 30-day readmission and length of stay, and 30-day mortality.

Overall, 604,537 adults with the mean age 55.3 years old underwent a surgical procedure and were identified by the investigators from the database. More than half (61.4%) were women.

Among the patients, 256,726 had laparoscopic and 37,311 had open cholecystectomies, 33,630 had laparoscopic and 128,513 had open ventral hernia repairs, and 62,366 had laparoscopic and 98,944 had open partial colectomies.

The rate of VTE within 30 days was low (1.1%), as well as rates of deep vein thrombosis (.8%) and pulmonary embolism (.4%). The mean diagnosis time of pulmonary embolism was shorter than deep vein thrombosis (10.3 days vs 11.4 days).

The rate of surgical site infection was 4.1% at 30 days, and general complications had a rate of 27%. The rate of major complications was 6.8% and the 30-day readmission rate was 7%.

For patients who underwent emergency surgery, they were on average older, more likely to be men, had a lower BMI, and had more comorbidities than those who elected to have surgery. Patients who underwent emergency general surgery had decreased risk of bleeding disorder and more risks for VTE, including prior cerebrovascular accident, history of disseminated cancer, and chemotherapy or radiotherapy over the last 30 days.

The risk of VTE increased with invasiveness (.5% for cholecystectomy, .8% for ventral hernia repairs, and 2.4% for partial colectomies; P <.001). Emergency general surgery was independently associated with VTE (OR, 1.7; 95% CI, 1.61-1.79).

Open surgery was also associated with VTE (OR, 3.38; 95% CI, 3.15-3.63), as well as partial colectomies (OR, 1.86; 95% CI, 1.73-1.99).

The findings of the data could be used to identify populations that could benefit from additional research to improve processes and reduce VTE risk.

The study, “Association of the Risk of a Venous Thromboembolic Event in Emergency vs Elective General Surgery,” was published online in JAMA Surgery.