Anticoagulant Strategy for Device Implantation
Abstract & Commentary
By John P. DiMarco, MD, PhD
Professor of Medicine, Division of Cardiology, University of Virginia, Charlottesville
Dr. DiMarco does research for Medtronic, is a consultant for Medtronic, Novartis, and St. Jude, and is a speaker for Boston Scientific.
Source: Bernard ML, et al. Meta-analysis of bleeding complications associated with cardiac rhythm device implantation. Circ Arrhythm Electrophysiol 2012;5:468-474.
In this paper, the authors perform a systematic review and meta-analysis of published reports comparing anticoagulation management strategies around the time of cardiac rhythm device implantation. Using standard techniques, the authors searched the medical literature and identified studies that assessed two or more anticoagulation strategies around the time of cardiac rhythm device implantation. Most of the reports identified were observational studies, not randomized, clinical trials. The potential strategies were as follows: group 1 — no therapy; group 2 — oral anticoagulation held (INR < 1.5); group 3 — oral anticoagulation continued (INR > 1.5); group 4 — single antiplatelet therapy; group 5 — dual antiplatelet therapy; and group 6 — heparin bridging strategy using either unfractionated or low molecular-weight heparin. Studies included in the meta-analysis had to have a report of bleeding complications using standard criteria and a description of follow-up. Major bleeding, in general, was defined as bleeding to transfusion, surgical intervention for pocket evacuation or revision, pericardial effusion, hemothorax, or other life-threatening bleed. All other bleeding was considered minor. Thromboembolic events were classified as transient ischemic attacks, cerebrovascular accidents, or any other systemic embolic events. Several statistical techniques were used to assess bias and heterogeneity.
The meta-analysis eventually included 13 studies involving 5978 patients. The lowest rate of bleeding was seen in patients receiving no anticoagulation or antiplatelet therapy. The highest rate of bleeding was noted with heparin bridging strategies. The estimated rate of bleeding complications for patients on no therapy was 1%. The estimated odds ratios for the strategies were 8.3 in the heparin bridging strategy group, 5.0 for dual antiplatelet therapy, 1.7 for oral anticoagulation held, 1.6 for oral anticoagulation continued, and 1.5 for single antiplatelet therapy. The risk for bleeding was significantly increased for both the dual antiplatelet therapy and the heparin bridging strategy groups. The heparin bridging strategy was associated with a 5.3-fold increase in increased bleeding compared to a strategy in which oral anticoagulation was continued. Minor bleeding events were more common than major bleeding events, but the relative distributions among the anticoagulation strategy groups were similar. Only seven studies reported thromboembolic events with a low cumulative event rate of nine of 2375 patients (0.4%). Rates of thromboembolic events were 0.5%, 0.2%, and 0.5% in the oral anticoagulation held, oral anticoagulation continued, and heparin bridging strategy groups, respectively.
The authors conclude that a strategy of continued conservative oral anticoagulation is superior to any heparin bridging strategy with regard to bleeding complications. This applies to all patients undergoing these procedures. Dual antiplatelet therapy also carries a higher risk of bleeding.
Commentary
Cardiologists and surgeons who implant pacemakers and ICDs must often deal with anticoagulation issues around the time of device insertion. In the past, a strategy that involved discontinuation of warfarin for several days and bridging with unfractionated or low molecular-weight heparin was recommended for high-risk patients, e.g., mechanical heart valves, recent thromboembolic events, and atrial fibrillation with CHADS2 scores of > 3. Physicians are also reluctant to hold dual antiplatelet therapy in patients with recent coronary stents. This meta-analysis shows that both a heparin bridging strategy and, to a lesser degree, dual antiplatelet therapy markedly increase bleeding risks and heparin bridging does little to increase safety.
Device-related bleeding is a nightmare for implanters. Early after implantation, the generator in the pocket prevents any effective use of pressure to stop bleeding, unless the bleeding is coming from the superficial suture line. Closed drainage of a pocket hematoma runs the risk of infection. Spontaneous resolution of a large hematoma may take weeks during which anticoagulation cannot be maintained at optimal levels. If a heparin bridging strategy is used, the problem occurs after the procedure when heparin is restarted. I have seen major bleeds as late as 7 days after implant in patients who were given heparin as warfarin was restarted.
The most important observation here is that device implants can be performed with low therapeutic INR values. This is the strategy adopted in my laboratory and we have found it be both safe and effective. We typically hold warfarin for only 0-48 hours so that the INR is near the low end of the therapeutic range and we have not had a problem with bleeding.
This meta-analysis doesn’t address how to manage patients on both dual antiplatelet therapy and an oral anticoagulant and patients receiving dabigatran or rivaroxaban. Further careful reports on experience with such patients would certainly be helpful.
In this paper, the authors perform a systematic review and meta-analysis of published reports comparing anticoagulation management strategies around the time of cardiac rhythm device implantation. Using standard techniques, the authors searched the medical literature and identified studies that assessed two or more anticoagulation strategies around the time of cardiac rhythm device implantation.You have reached your article limit for the month. Subscribe now to access this article plus other member-only content.
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