With modern anaesthesia, most orthopaedic operations are straight forward.
With proper pain management, the patient can usually get up and walk immediately after surgery. Thus, they do not represent much risk to patients from the traditional post operative complications.
Some patients are on powerful anticoagulants, particularly for irregular heart rhythm (Atrial Fibrillation or AF). Traditional advice is stop the patient’s warfarin or Rivaroxaban (Xarelto), and commence a different blood thinner – say Clexane. This is called bridging therapy. The alternate approach is to stop the powerful agent and recommence it after surgery, accepting a risk in the realm of 0.1% that the patient might have a stroke in the interval.
Major studies have now demonstrated the reason for bridging therapy is limited to previous pulmonary embolism, previous CVA caused by embolism, and some mechanical heart valves. Of all patients on anticoagulants, only perhaps 5% need bridging treatment. There are many guidelines suggesting bridging is required, but invariably the committee deciding had financial interests in anticoagulants.
| CHADS2 score | ||
|---|---|---|
| C | Congestive Heart Failure | 1 |
| H | Hypertension (SBP>140) | 1 |
| A | Age >= 75 | 1 |
| D | Diabetes Mellitus | 1 |
| S2 | Prior stroke, TIA or PE | 2 |
| Annual stroke risk based on CHADS2 score & 5 day risk | Annual stroke risk | 5 Day Risk |
|---|---|---|
| zero – Atrial Fibrillation but no other risk factors |
1.90%
|
0.03%
|
| 1 |
2.80%
|
0.04%
|
| 2 |
4.00%
|
0.05%
|
| 3 |
5.90%
|
0.08%
|
| 4 |
8.50%
|
0.12%
|
| 5 |
12.50%
|
0.17%
|
| 6 | 18.20% |
0.25%
|
The time actually without effective anticoagulation is often less than 5 days.
References:
1. Breen DT, Chavalertsakul N, Paul E, Gruen RL, Serpell J. Perioperative complications in patients on low molecular weight heparin bridging therapy. ANZ J Surg 86 (2016) 167-72
2. Douketis JD, Spyropoulos AS, Spencer FA et al., Perioperative management of antithrombotic therapy: Antithrombotic Therapy and prevention of thrombosis, 9th ed: American College of Chest Physicians Evidence Based Clinical Practice Guidelines. Chest 2012; 141 e326S-50S.
3. Jorgensen CC, Kehlet H, Thromboembolic and major bleeding events in relation to preoperative bridging of vitamin K antagonists in 649 fast track total hip and knee replacement
4. Preoperative bridging anticoagulation in patients with atrial fibrillation. N Eng J Med, 2015: 373: 823-833
Mr David Mitchell
