Navigating the anticoagulant landscape in 2017
ABSTRACT
Several questions remain regarding anticoagulant management: What is the best strategy for managing acute venous thromboembolism? How should patients on a direct oral anticoagulant or on warfarin be managed when they need elective surgery? When is heparin bridging necessary?
KEY POINTS
- Venous thromboembolism has a myriad of clinical presentations, warranting a holistic management approach that incorporates multiple antithrombotic management strategies.
- A direct oral anticoagulant is an acceptable treatment option in patients with submassive venous thromboembolism, whereas catheter-directed thrombolysis should be considered in patients with iliofemoral deep vein thrombosis, and low-molecular-weight heparin in patients with cancer-associated thrombosis.
- Perioperative management of direct oral anticoagulants should be based on the pharmacokinetic properties of the drug, the patient’s renal function, and the risk of bleeding posed by the surgery or procedure.
- Perioperative heparin bridging can be avoided in most patients who have atrial fibrillation or venous thromboembolism, but should be considered in most patients with a mechanical heart valve.
Is aspirin safe during surgery?
Evidence concerning aspirin during surgery comes from Perioperative Ischemic Evaluation 2 (POISE-2), a double-blind, randomized controlled trial.30 Patients who had known cardiovascular disease or risk factors for cardiovascular disease and were about to undergo noncardiac surgery were stratified according to whether they had been taking aspirin before the study (patients taking aspirin within 72 hours of the surgery were excluded from randomization). Participants in each group were randomized to take either aspirin or placebo just before surgery. The primary outcome was the combined rate of death or nonfatal myocardial infarction 30 days after randomization.
The study found no differences in the primary end point between the two groups. However, major bleeding occurred significantly more often in the aspirin group (4.6% vs 3.8%, hazard ratio 1.2, 95% confidence interval 1.0–1.5).
Moreover, only 4% of the patients in this trial had a cardiac stent. The trial excluded patients who had had a bare-metal stent placed within 6 weeks or a drug-eluting stent placed within 1 year, so it does not help us answer whether aspirin should be stopped for our current patient.
Is surgery safe for patients with stents?
The safety of undergoing surgery with a stent was investigated in a large US Veterans Administration retrospective cohort study.31 More than 20,000 patients with stents who underwent noncardiac surgery within 2 years of stent placement were compared with a control group of more than 41,000 patients with stents who did not undergo surgery. Patients were matched by stent type and cardiac risk factors at the time of stent placement.
The risk of an adverse cardiac event in both the surgical and nonsurgical cohorts was highest in the initial 6 weeks after stent placement and plateaued 6 months after stent placement, when the risk difference between the surgical and nonsurgical groups leveled off to 1%.
The risk of a major adverse cardiac event postoperatively was much more dependent on the timing of stent placement in complex and inpatient surgeries. For outpatient surgeries, the risk of a major cardiac event was very low and the timing of stent placement did not matter.
A Danish observational study32 compared more than 4,000 patients with drug-eluting stents having surgery to more than 20,000 matched controls without coronary heart disease having similar surgery. The risk of myocardial infarction or cardiac death was much higher for patients undergoing surgery within 1 month after drug-eluting stent placement compared with controls without heart disease and patients with stent placement longer than 1 month before surgery.
Our practice is to continue aspirin for surgery in patients with coronary stents regardless of the timing of placement. Although there is a small increased risk of bleeding, this must be balanced against thrombotic risk. We typically stop clopidogrel 5 to 7 days before surgery and ticagrelor 3 to 5 days before surgery. We may decide to give platelets before very-high-risk surgery (eg, intracranial, spinal) if there is a decision to continue both antiplatelet drugs—for example, in a patient who recently received a drug-eluting stent (ie, within 3 months). It is essential to involve the cardiologist and surgeon in these decisions.
BOTTOM LINE
