Perioperative VTE Prophylaxis Gregory J. Misky, M.D. Assistant Professor of Medicine University Of Colorado Denver You recommend the following 72 y.o. man admitted for an elective R hip repair. Patient has HTN, DM and h/o a LLE DVT following L THR one year previously. Surgery is scheduled for the following day. a. Unfractionated Heparin TID when cost is a concern b. Avoidance of Warfarin as it is ineffective and contraindicated c. Enoxaparin initiated twelve hours following repair and given daily until patient is discharged d. Enoxaparin started the following morning and continued daily for > 28 days D While LDUH is cheaper than LMWH, it is recommended against in patients undergoing elective THR (1A) Warfarin (adjusted dose) and Fondaparinux are both acceptable, recommended VTE prophylactic regimens in THR patients (1A) LMWH is a 1A recommendation Duration of recommended VTE prophylaxis for elective THA patients is a minimum of 10 days
Perioperative VTE Risk Risk of proximal DVT is 10-15% if not placed on appropriate VTE prophylaxis Effective and timely VTE prophylaxis for THR has diminished the risk to <1% Incidence of symptomatic VTE highest following discharge VTE is the most common reason for readmission to the hospital after THR VTE Risk Combined rates of venographic DVT and proximal DVT at 7 and 14 days after major orthopedic surgery without VTE prophylaxis: 40-60% and 10-30%, respectively Rates of symptomatic VTE: 1.3-10% within 3 months of surgery Routine VTE prophylaxis has made fatal PE uncommon Clot vs. Bleed Balance of clot risk vs. bleed risk Orthopedic view may differ from Chest Guidelines DVT (esp. distal or venographic) may not be accurate marker of PE, i.e. Venographic DVT may not = Symptomatic VTE sig. bleeding rates with prophylaxis: 1.8%-5% For patients actively bleeding, especially a joint hematoma, anticoagulation should be held with mechanical VTE prophylaxis implemented follow-up collaborative discussions with the Orthopedic team on when to restart appropriate VTE prophylaxis
Elective Hip Repair For patients undergoing elective THR, the following VTE prophylaxis are recommended (1A): LMWH started 12-24 hours after surgery (or 12 hours prior to surgery) can give half-dose LMWH 4-6 hrs. post-op Fondaparinux 2.5 mg started 6-24 hours post-op Warfarin started evening of surgery (adjusted dose, INR target 2.5) * Aspirin and LDUH recommended against Elective Knee Repair Overall risk of DVT higher in elective TKR than THR proximal DVT less common period of increased risk for symptomatic VTE after discharge shorter For patients undergoing elective TKR, the following VTE prophylaxis options are recommended: LMWH Fondaparinux Warfarin * IPC an alternative when bleed risk high Hip Fracture Repair Rates of total and proximal DVT: 50% and 27%, respectively Symptomatic, objectively confirmed VTE: 1.3%-8.2% with routine prophylaxis fatal PE: 0.4%-7.5% within 3 months higher than elective THA/TKA initial injury, surgical repair, advanced age, delayed surgery Few VTE prophylaxis studies
Hip Fracture Repair Recommended Prophylaxis: Fondaparinux (1A) LMWH (1B) Warfarin, adjusted-dose (1B) LDUH (1B) If surgery delayed, initiate prophylaxis with LMWH or LDUH pending surgery Knee Arthroscopy LMWH reduces the incidence of asymptomatic DVT, but with a higher bleeding rate More evidence needed to recommend routine LMWH prophylaxis Early mobilization recommended as routine prophylaxis unless additional VTE risks present Timing Efficacy of VTE prophylaxis is enhanced the closer to the proximity of surgery, but bleeding risk is also increased: bleed risk > VTE prevention in patients started on LMWH right before surgical repair LMWH can be started either preoperatively or postoperatively (initial dose can be given 12-24 hours after surgery) Withholding all preoperative LMWH > one day increases a vulnerable VTE risk window
Duration For patients undergoing THR or hip fracture surgery, extended VTE prophylaxis (>10 days, up to 35 days) is recommended if patient considered to be high risk for VTE (1A): previous VTE advanced age obesity delayed immobilization cancer Variables: Cost/insurance benefits and patient factors (shots, lab follow-up, cognitive status) Spine Surgery Ambulation recommended as primary VTE prevention given the risk-benefit if patient without other identifiable VTE risks In patients without additional VTE risks, routine thromboprophylaxis recommended against (1C) For anterior surgical approach, or patients with additional VTE risk factors (advanced age, cancer, neurologic deficit or previous VTE), one of the following recommended: post-op LDUH post-op LMWH perioperative IPC Neurosurgery Moderate VTE risk, esp. intracranial surgery, cancer, leg weakness, age Recommendation: IPC (optimal): 1A LMWH, post-op (2A) or LDUH (2B) High VTE risk: mechanical (IPC/GCS) + pharmacologic (LMWH/LDUH)
Lower Extremity Knee ligament injuries, Achilles tendon rupture, ankle injuries LMWH reduces rate of asymptomatic calf DVT may not reduce rate of clinically significant VTE events not cost effective Recommendation: Patients with isolated leg injuries distal to the knee and without other identifiable VTE risks do not require routine thromboprophylaxis Upper Extremity Shoulder/arm Few good studies No formal guidelines Patients who undergo shoulder arthroplasty have overall rates of VTE lower than patients who undergo hip and knee replacements, but the percentage of PE among VTE events is higher General Surgery Rates of DVT prior to VTE prophylaxis: 15%-30% Fatal PE: 0.2%-0.9% Increased risk of VTE: traditional risks- cancer, previous VTE, obesity age type of anesthesia (general > epidural) LMWH and LDUH have similar efficacy and bleeding rates Higher doses of LMWH more protective than lower doses (dalteparin 5000u > 2500u in cancer patients)
General Surgery Low-risk surgical patients (inc. laparoscopy*) without VTE risks: early, frequent ambulation * laparoscopy with VTE risks: LMWH, LDUH, fondaparinux or IPC/GCS Moderate-risk surgery for benign disease: LMWH, LDUH, or fondarinux Higher-risk surgery for cancer: LMWH, LDUH (TID), or fondaparinux General surgery with multiple VTE risks: Pharmacologic (LMWH, LDUH (TID), or fondaparinux) combined with mechanical Urology Rates of symptomatic VTE: 1-5%; only one randomized clinical trial on VTE prophylaxis Low-risk procedures (e.g. TURP, laparoscopy): ambulation recommended over others High-risk procedures (e.g. Open procedures- radical prostatectomy, cystectomy and nephrectomy): LDUH BID-TID or continuous GCS/IPC: 1B LMWH and fondaparinux: 1C Actively bleeding patients: mechanical prophylaxis until bleeding risk lowered Gynecology Low-risk or laparoscopic: ambulation Major surgery for benign disease: LMWH, LDUH or IPC Extensive GYN-ONC and patients with VTE risks: LMWH, LDUH TID or IPC (or combination)
Obesity/Bariatric Surgery Variable VTE incidence reported after bariatric surgery Only one small randomized trial of prophylaxis Unknown dosage, timing and duration of VTE prophylaxis Bariatric surgery recommendation: LMWH, LDUH TID, fondaparinux (or combination) Higher doses of LMWH or LDUH than usual Renal Disease Variability in drug accumulation Serial anti-factor Xa levels may not accumulate In patients with Creatinine clearance <30 ml/min, LMWH should be dose-adjusted As Fondaparinux is cleared renally, it is not an alternative to LMWH in patient with advanced renal disease Final Thoughts What endpoint? Bleed/Thrombosis balance Enoxaparin: Daily vs. BID LMWH vs. Fondaparinux