Prospective Study on Preoperative Versus Postoperative Venous Thromboprophylaxis in Patients Undergoing Major Colorectal Surgery
Condition: Venous Thromboembolism
MeSH terms: Thromboembolism; Venous Thromboembolism
Intervention: Heparin
Intervention description: Subcutaneous Heparin 5000 Units given in the preoperative area one hour prior to surgery and continued every 8 hours for the remainder of the patients hospital course
Intervention MeSH terms: Heparin
Phase: Phase 3
Study type: Interventional
Primary purpose: Prevention
Allocation: Randomized
Intervention model: Parallel Assignment
Masking: None (Open Label)
Enrollment: 410.0
Sex: All
Minimum age: 18 Years
Healthy volunteers: No

Summary:

      Patients undergoing major colorectal surgery are at increased risk for VTE (deep venous
      thrombosis) compared with patients undergoing other general surgical procedures (Bergqvist et
      al. Dis. Col. Rectum. 2006; 49: 1620-1628.)

      The reported incidence of symptomatic VTE after colorectal surgery is approximately 4% (Monn,
      F. et al. JACS. 216; 2013: 395-401). However, the reported incidence of VTE after colorectal
      surgery in prospectively followed patients managed with perioperative venous
      thromboprophylaxis undergoing screening venography prior to hospital discharge ranges from 9
      to 20% (Bergovist et al. NEJM 346; 2002: 975-980; McLeod et al. Ann. Surg. 233; 2000:
      438-444; ENOXACAN Study group. Brit. J. Surg. 84; 1997: 1099-1103.

      The Surgical Care Improvement Project (SCIP) and the American College of Chest Physician
      (ACCP) guidelines recommend that venous thromboprophylaxis be initiated within 24 hours of
      surgery. However, it is believed that deep venous thrombosis occurs during surgery, rather
      than in the postoperative period, justifying preoperative initiation of venous
      thromboprophylaxis. This practice is accompanied with a theoretically higher risk of bleeding
      complications.

      Currently there is no consensus on the precise timing of VTE prophylaxis after major
      colorectal surgery, as demonstrated by the vague guidelines established by the ACCP and SCIP.
      Current studies on VTE prophylaxis report preoperative initiation of VTE prophylaxis.
      However, majority of surgeons at our institution begin heparin postoperatively given concern
      for bleeding complications with preoperative dosing of heparin.

      The purpose of this study is to prospectively evaluate the incidence of VTE and major
      bleeding complications in patients undergoing major colorectal surgery who are treated with
      preoperative or postoperative venous thromboprophylaxis and to help establish more stringent
      guidelines on the optimal timing of VTE prophylaxis.
    

Eligibility criteria:

        Inclusion Criteria:

          1. Able to freely give written informed consent to participate in the study and have
             signed the Informed Consent Form;

          2. Males or females, age 18 and older at the time of study screening;

          3. American Society of Anesthesiologists (ASA) Class I-III (Appendix III);

          4. Due to undergo major colorectal surgery via laparotomy or laparoscopy

        Exclusion Criteria:

          1. Mentally incompetent or unable or unwilling to provide informed consent or comply with
             study procedures;

          2. American Society of Anesthesiologists (ASA) Class IV or V;

          3. Children <18

          4. Pregnant patients

          5. Current/Active DVT

          6. Patients on therapeutic anticoagulation for DVT or PE at time of surgery

          7. Patients on anticoagulation for other medical problem (Heart Valve/atrial
             fibrillation) at the time of surgery

          8. Patients with IVC filter

          9. History of allergy to heparin products

         10. History of heparin induced thrombocytopenia (HIT)

         11. Patients with recent or active hemorrhage (GI/intracranial, etc) felt by the attending
             surgeon to be a contraindication to heparin thromboprophylaxis

         12. Patients with Epidural analgesia