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Management of Antithrombotic Therapy with Device Placement
Abstract & Commentary
By John P. DiMarco, MD, PhD, Professor of Medicine, Division of Cardiology, University of Virginia, Charlottesville. Dr. DiMarco receives grant/research support from St. Jude Medical, Astellas, and Novartis, is a consultant for Medtronic and Sanofi-Aventis, and is a speaker for St. Jude Medical and Boston Scientific.
Source: Tompkins C, et al. Dual-antiplatelet therapy and heparin "bridging" significantly increase the risk of bleeding complications after pacemaker or implantable cardioverter-defibrillator device implantation. J Am Coll Cardiol. 2010;55:2376-2382.
Many patients who receive pacemakers or implantable cardioverter defibrillators (ICDs) are chronically treated with antiplatelet agents, warfarin, or a combination of the two. In this paper, Tompkins and colleagues from the Johns Hopkins Hospital report the results of a retrospective review of antiplatelet and anticoagulant management in patients receiving cardiac-rhythm devices. The records of patients who received a cardiac-rhythm management device over a three-year period were retrospectively reviewed. The final study group included 1,388 patients. Of these, 675 patients were receiving antiplatelet agents, 458 patients had received either warfarin or heparin anticoagulation, and 255 patients were not on either antiplatelet or anticoagulation medications. Patients on both warfarin and clopidogrel were excluded, since there were few with this history. Management of antiplatelet and anticoagulation drugs during the peri-procedural period was at the discretion of the implanting electrophysiologist. Primary events included bleeding complications, which required a pocket exploration, blood transfusion, or pressure dressings, changes in medical therapy, or prolonged hospitalization. Thrombosis-related complications included stroke or transient ischemic attack, myocardial infarction, and venous thrombosis. Other complications that were analyzed included cardiac tamponade, pneumothorax, lead dislodgement, and pericarditis.
Of the 1,388 patients, 905 (65%) were male. Pacemakers were implanted in 556 patients (40%) and ICDs in 832 patients (60%). There were 71 bleeding complications (5.1%) noted in the study. Hematomas were noted in 41 patients, and antiplatelet or anticoagulation therapy had to be withheld in 17. However, there were only five patients who required a pocket exploration, four patients who required blood transfusion, and four patients who had a prolonged hospitalization. Antiplatelet agents affected the rate of bleeding complications. Patients who were not on antiplatelet agents had a bleeding complication rate of 1.6%. Patients receiving aspirin only had a bleeding complication rate of 3.9%. Patients receiving both aspirin and clopidogrel had a significantly higher bleeding-complication rate of 7.2%. Patients who received warfarin were grouped into those in whom the INR at the time of the procedure was ≥ 1.5 and those in whom the INR < 1.5. In both groups, warfarin use increased the risk of bleeding complication. The bleeding rate was 6.5% in patients with an INR < 1.5 and 4.3% in those where the INR was > 1.5. Heparin bridging markedly increased the risk of bleeding complications. The risk of bleeding was 14.3% in patients who received heparin around the time of their event even though heparin was stopped an average of 9.4 + 8.8 hours pre-procedure and not restarted until 22 + 15.6 hours after device implantation.
A multivariate analysis of predictors for bleeding complications also was performed. Dual-antiplatelet therapy (OR - 3.84) and heparin use (OR - 9.8) remained significant independent predictors of bleeding complications. Other factors associated with increased bleeding complications were male gender and a longer procedure time. Patients who were overweight or African-Americans had a decreased risk of bleeding complications.
Ischemic events were rare in the study cohort. There were no myocardial infarctions. Two patients had transient ischemic attacks with complete resolution, and one patient had an ischemic stroke. Upper-extremity deep-venous thrombosis was decreased with both antiplatelet and anticoagulant therapy. Other complications were not affected or notably worsened by the use of antiplatelet or anticoagulation agents. In the entire series, there were six cases with pericardial tamponade, 12 pneumothoraces, 29 lead dislodgments, and five cases of pericarditis.
The authors conclude that peri-procedural heparin markedly increases the risk of bleeding complications and should be avoided. They recommend that for patients with low thromboembolic risk, antiplatelet or anticoagulation medications should be withheld for 3-5 days pre-procedure. In patients at high risk for ischemic events, continuation of antiplatelet agents or warfarin is preferable to use of heparin.
The results of this paper are in agreement with my personal experience and the experience in our laboratory at the University of Virginia. Over the years, we have noted that bleeding complications are markedly increased when heparin bridging is used around the time of any device implantation. Currently, we do not withhold aspirin in any patient. We continue clopidogrel in patients with drug-eluting stents and in patients with recent bare-metal stents. In patients on warfarin who have either prosthetic mechanical valves or a history of embolic events, we try to perform the procedure with an INR between 1.8 and 2.5 and restart warfarin the night after the procedure if the pocket looks normal. With this approach, hematomas that require intervention have been very uncommon.
The greatest danger in a device patient on antiplatelet or anticoagulants is that a large hematoma will form. Hematomas, whether or not they require reoperation, increase the risk for infection. When a hematoma develops, anticoagulants often need to be held and the patient's activity restricted. External pressure can be ineffective, since the metallic surface of the device inhibits coagulation. Even when you reopen the pocket to evacuate a hematoma, it's often hard to identify any specific bleeding site, and reformation of the hematoma is likely.
We also are seeing an increased number of patients who are on triple antithrombotic therapy with aspirin, clopidogrel, and warfarin. Such patients were not included in this paper. Again, in these patients, we've found it best to operate with an INR just below the desired range and avoid any use of heparin. Also, strict attention to surgical technique is critical in these patients.