The perioperative bleeding risk associated with therapeutic anticoagulation at cardiac implantable electronic device implantation has previously been demonstrated to vary by the specific anticoagulant used. Although uninterrupted anticoagulation with warfarin appears to be safe, heparin products have been shown to increase the risk of perioperative bleeding. However, the risk associated with cardiac implantable electronic device implantation with anticoagulation using dabigatran, a novel oral direct thrombin inhibitor, is not known. We performed a prospective observational study of patients receiving dabigatran for anticoagulation who underwent cardiac implantable electronic device implantation from June 2011 through May 2012. The study end points included thromboembolic and bleeding complications within 30 days of surgery. Major bleeding complications were defined as bleeding requiring surgical intervention, prolongation of hospitalization, and discontinuation of the anticoagulant or transfusion of blood products within 30 days of surgery. Minor bleeding complications included the development of a hematoma not requiring additional intervention. The thrombotic end points included stroke, transient ischemic attack, myocardial infarction, pulmonary embolism, and deep vein thrombosis. A total of 25 patients were identified for inclusion. During the index hospitalization, no thromboembolic or bleeding complications developed. No major bleeding complications occurred within 30 days of surgery. One minor bleeding event (4%) occurred within 30 days of surgery in 1 patient who was also receiving dual antiplatelet therapy. In conclusion, although no thromboembolic or major bleeding events were observed, additional studies are required to define the optimal antithrombotic management in the perioperative period.
Patients requiring implantation of cardiac implantable electronic devices (CIEDs) frequently have co-morbidities necessitating long-term anticoagulation, which increases the risk of bleeding complications. The optimal strategy for managing anticoagulation in association with pacemaker or implantable cardioverter defibrillator (ICD) procedures has been extensively evaluated. Early guidelines recommended withholding warfarin in patients at low risk of thromboembolic events and using a heparin bridging strategy in moderate- to high-risk patients. Although 1 randomized, controlled study found no increased risk associated with heparin bridging, more recently, it has become clear that uninterrupted anticoagulation with warfarin results in fewer bleeding complications during CIED implantation than bridging strategies using either unfractionated or low-molecular-weight heparin products. Although an ongoing study has been evaluating the safety of continuous oral anticoagulation with warfarin during CIED implantation, the safety and optimal dosing of newly approved oral anticoagulant agents during CIED implants is less well studied. Accordingly, the present study was designed to assess the safety and bleeding risks of dabigatran during CIED implantation.
Methods
The present prospective, observational study was performed from June 2011 through May 2012. All patients gave informed consent for device implantation, and the Medical University of South Carolina institutional review board approved the study. Consecutive patients undergoing implantation of an initial pacemaker, ICD, cardiac resynchronization therapy device, or pulse generator replacement receiving anticoagulation with dabigatran within 48 hours of the procedure were included for analysis. All procedures were performed with standard techniques for subcutaneous pectoral pocket formation and transvenous lead placement by way of the axillary vein using active fixation leads. The ICD leads were positioned at the right ventricular apex, and the right ventricular pacemaker leads were usually targeted to the interventricular septum. The perioperative dosing of dabigatran was left to the discretion of the implanting physician. Routine follow-up examinations were performed in 1 month, at which time the surgical site was reassessed.
Patient demographics, co-morbidities, medication history, and procedural details were collected at implantation. The study end points were prospectively evaluated and included complications occurring during the index hospitalization and at 30 days of follow-up. Major bleeding complications were defined as bleeding requiring surgical intervention, prolongation of hospitalization, and discontinuation of the anticoagulant or transfusion of blood products within 30 days of surgery. Minor bleeding complications included the development of a hematoma not requiring additional intervention. The thrombotic end points included stroke, transient ischemic attack, myocardial infarction, pulmonary embolism, and deep vein thrombosis.
All values are reported as the mean ± SD, except as otherwise stated. Statistical analysis was performed using Fisher’s exact test for categorical data and Student’s t test for continuous variables. Relative risk was calculated using standard methods.
Results
The present study included 25 consecutive patients who were undergoing device implantation or replacement and who were anticoagulated with dabigatran during the procedure. The baseline patient characteristics are listed in Table 1 . Full dose dabigatran at 150 mg twice daily was used for anticoagulation in 22 patients (88%); 2 patients (8%) received reduced dose dabigatran (75 mg twice daily) because of chronic kidney disease. The remaining patient received anticoagulation with full dose dabigatran before the implant procedure and reduced dose dabigatran after the procedure. The mean change in hemoglobin after implantation was −0.14 ± 0.77 g/dl. No patient received heparin products within 24 hours of the procedure.
| Baseline Characteristics | Value |
|---|---|
| Age (yrs) | 66 ± 11 |
| Men | 22 (88%) |
| Left ventricular ejection fraction (%) | 45 ± 19 |
| CHADS 2 score | 2.1 ± 1.4 |
| Implant procedure | |
| Implantable cardioverter defibrillator | 6 (24%) |
| Permanent pacemaker | 9 (36%) |
| Cardiac resynchronization therapy | 5 (20%) |
| Pulse generator change out | 5 (20%) |
| Indications for oral anticoagulation | |
| Paroxysmal atrial fibrillation | 7 (28%) |
| Persistent atrial fibrillation | 11 (44%) |
| Permanent atrial fibrillation | 3 (12%) |
| Atrial flutter | 4 (16%) |
| Aspirin | 12 (48%) |
| Thienopyridine | 2 (8%) |
| International normalized ratio | 1.3 ± 0.3 |
The last dose of the anticoagulant was given 16 ± 15 hours (range 1 to 48) before implantation, and the first dose of the anticoagulant was given 17 ± 16 hours (range 2 to 48) after the procedure. In 11 patients (44%), dabigatran was administered uninterrupted with no missed doses. These 11 patients had CHADS 2 (Congestive heart failure, Hypertension, Age >75 years, Diabetes mellitus, and previous Stroke or transient ischemic attack [doubled]) scores similar to those of the remaining cohort (2 ± 1.7 vs 2.2 ± 1), but they were more likely to have had recent or potential cardioversion (73% vs 21%, respectively; p = 0.02). The interval between the last dose of dabigatran and implantation was 26 ± 16 hours (range 5 to 48) for the group with minimally interrupted anticoagulation and 5 ± 3 hours (range 1 to 11) for the uninterrupted group (p = 0.0003). The interval between implantation and the first postoperative dose of dabigatran was 27 ± 19 hours (range 2 to 48) in the minimally interrupted group and 8 ± 3 hours (range 3 to 11) in the uninterrupted group (p = 0.003).
During the index hospitalization, no major or minor bleeding events and no thromboembolic events occurred. The 30-day follow-up data were complete for all patients. One minor bleeding event (4%) occurred in 1 patient, who developed a pocket hematoma that did not require additional intervention or discontinuation of the anticoagulant. This patient had been receiving dual antiplatelet therapy with clopidogrel and aspirin, as well as full-dose uninterrupted dabigatran because of a CHADS 2 score of 6. No major bleeding events or thromboembolic events occurred within 30 days of surgery. The relative risk of minor complications using uninterrupted dabigatran was 3.75 (95% confidence interval 0.17 to 84, p = 0.4).
Results
The present study included 25 consecutive patients who were undergoing device implantation or replacement and who were anticoagulated with dabigatran during the procedure. The baseline patient characteristics are listed in Table 1 . Full dose dabigatran at 150 mg twice daily was used for anticoagulation in 22 patients (88%); 2 patients (8%) received reduced dose dabigatran (75 mg twice daily) because of chronic kidney disease. The remaining patient received anticoagulation with full dose dabigatran before the implant procedure and reduced dose dabigatran after the procedure. The mean change in hemoglobin after implantation was −0.14 ± 0.77 g/dl. No patient received heparin products within 24 hours of the procedure.
| Baseline Characteristics | Value |
|---|---|
| Age (yrs) | 66 ± 11 |
| Men | 22 (88%) |
| Left ventricular ejection fraction (%) | 45 ± 19 |
| CHADS 2 score | 2.1 ± 1.4 |
| Implant procedure | |
| Implantable cardioverter defibrillator | 6 (24%) |
| Permanent pacemaker | 9 (36%) |
| Cardiac resynchronization therapy | 5 (20%) |
| Pulse generator change out | 5 (20%) |
| Indications for oral anticoagulation | |
| Paroxysmal atrial fibrillation | 7 (28%) |
| Persistent atrial fibrillation | 11 (44%) |
| Permanent atrial fibrillation | 3 (12%) |
| Atrial flutter | 4 (16%) |
| Aspirin | 12 (48%) |
| Thienopyridine | 2 (8%) |
| International normalized ratio | 1.3 ± 0.3 |
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