br Conclusion br Conflict of interest br Introduction Recent
Conflict of interest
Introduction Recent trials of the use of implantable electronic devices, including implantable cardioverter defibrillators (ICDs) and cardiac resynchronization therapy defibrillators (CRT-Ds) show survival benefits [1–3]. As a result, implantable electronic devices are being used with increasing frequency and the population of candidates for implantable electronic devices has expanded to include patients with additional comorbidities, such as atrial fibrillation, poor left ventricular systolic function, or the presence of mechanical cardiac valves. These patients are generally orally anticoagulated to reduce the risk of thromboembolism. Discontinuation of anticoagulation therapy may increase risk of thromboembolism [4–6], and therefore current guidelines recommend the cessation of oral anticoagulation in favor of heparin bridging during the perioperative period [7–10]. In some studies, it has been shown that heparinization is associated with an increased risk of hematoma development, while oral anticoagulation therapy with warfarin did not increase the rate of pocket hematoma [5,11–15]. There have been no reports on the relationship between anticoagulation and bleeding complications after device AMG-517 in Japan.
Device implantation Anticoagulation therapy with warfarin was temporarily discontinued 2 day before device implantation. In some patients, who were thought to be at high risk of thromboembolism, such as those with a mitral mechanical valve, heparin bridging was performed. Continuous infusion of heparin targeted the activated partial thromboplastin time from 1.5 to 2.5 times as much as the control value before infusion. Administration of heparin was stopped 6h before the procedure. Antiplatelet therapy was allowed to continue. We did not use postoperative drainage systems because a previous study did not find a significant reduction of pocket bleedings by using drainage systems . The patients were given a single dose of cefazolin (1.0g) intravenously just before the procedure, following a previous study revealing the efficacy of antibiotic prophylaxis before the implantation of cardiac devices . If the procedure lasted longer than 3h, an additional 1.0g dose of cefazolin was added. Infusion of heparin was restarted 3h after the procedure and warfarin was restarted the next day. If the patients suffered massive bleeding during surgery, we delayed the restart of heparin or warfarin. In addition, when the international normalized ratio (INR) increased to >1.6, we stopped heparin infusion. The majority of patients were discharged one week after the operation.
Statistical analysis Statistical significance was calculated by the χ2 test or Fisher\'s exact test for categorical variables and the t-test for continuous variables. Multivariate logistic regression analysis was used to determine significant factors for complications. The data are expressed as mean±standard deviation. A P value<0.05 was considered significant.
Complications Pocket hematoma was observed in 10 (6.2%) patients, and 4 of 10 patients received blood transfusion and 1 patient needed evacuation for hematoma. Device infection was observed in 1 (0.6%) patient who did not experience pocket hematoma preceding infection. He underwent device extraction and reimplantation in the opposite side subpectoral site. There were no cases of thromboembolism (Table 3). There were no differences in the basic characteristics and underlying disease between patients with and without complications (Table 4). CRTD implants were more likely to be included in the complications group, but not significantly so. Complications were not associated with warfarin (P=0.19) or antiplatelet therapy (P=0.69); however, heparin bridging was performed significantly more often in the complication group (P=0.005). In heparinized patients, preoperative APTTs were similar in the 2 groups (76.6±66.6 vs. 73.3±9.5, P=0.92).