Need for cardiac implantable electronic devices and long-term follow-up in recipients of orthotopic heart transplants.

BACKGROUND: Cardiac pacemaker implantation after orthotopic heart transplantation declined dramatically after development of the bicaval anastomosis technique. However, much less is known about the rate, indications, and predictors of device implantation procedures with the current surgical technique. OBJECTIVE: The purpose of this study was to evaluate the indications, patient characteristics, incidence, and survival related to cardiac implantable electronic device (CIED) implantation after heart transplantation. METHODS: This was a single-center study of 399 consecutive adult recipients of orthotopic heart transplants with bicaval anastomosis from 1991 to 2017. The primary end point was freedom from pacemaker or implantable cardioverter-defibrillator (ICD) implantation, and the secondary end point was all-cause mortality. RESULTS: At the time of transplantation, the mean age of recipients was 50 ± 12 years and that of donors 31 ± 12 years. CIEDs were implanted in 8% of recipients (n = 31): 11 pacemakers (35%) for sinus node dysfunction, 17 (55%) for high-grade heart block, and 3 ICDs (10%) for the primary prevention of sudden cardiac death. Early CIED implantation (<30 days) was rare and absent for sinus node dysfunction. The risk for CIED implantation increased progressively during follow-up (0-30 years; median 11 years), with low-, moderate-, and high-risk periods between 0 and 10, between 10 and 20, and between 20 and 30 years, respectively. Recipients receiving CIEDs survived longer after transplantation (21 years vs 13 years; P < .01). Recipients receiving pacemakers for heart block were more likely to receive older donor hearts at the time of transplantation. CONCLUSION: The risk of pacemaker implantation increases progressively, while ICD implantation is rare. Donor age is the predominant risk factor for subsequent heart block. Early sinus node dysfunction requiring permanent pacing is rare.

Postoperative Antibiotic Prophylaxis Following Cardiac Implantable Electronic Device Placement.

Infections related to cardiac implantable electronic device (CIED) placement are associated with poor clinical outcomes. As such, preprocedural prophylactic antibiotic therapy is indicated for all patients prior to device insertion. However, the available data are less clear on the impact of postprocedural antibiotic therapy on rates of CIED infection when used in addition to preprocedural therapy. This is single-center, retrospective cohort study of 913 patients who underwent CIED-related procedures between October 2010 and August 2014 sought to compare the rate of CIED infections in patients receiving only preprocedural antibiotics with those receiving both preprocedural and postprocedural antibiotics. Univariate analysis was used to detect independent risk factors for CIED infection. After excluding patients receiving concomitant antibiotics for other conditions, those undergoing CIED extraction alone, and those with a lack of follow-up data and/or adequate documentation of clinical encounters, 569 patients were identified for inclusion in the final analysis. The majority of patients who received postprocedural antibiotics received three to five days of therapy, with the most common antibiotic used being cephalexin. There was no statistically significant difference in the incidence of infection between patients who did and did not receive postoperative antibiotics (4.5% versus 6.1%; p = 0.398). In a multivariate analysis, the use of postprocedural antibiotic therapy was not a significant risk factor for infection (adjusted odds ratio: 0.692; 95% confidence interval: 0.314-1.525; p = 0.361). It is therefore reasonable to withhold prescribing postoperative antibiotics in patients following CIED implantation. Individualized risk factor evaluation of patient comorbidities and procedural characteristics may be needed to aid in determining whether postoperative antibiotics are reasonable in different patients. The validity of these findings is contingent on further confirmation via a prospective, randomized clinical trial.

Thromboprophylaxis Failure in the Adult Medical Inpatient.

Venous thromboembolism (VTE), a leading cause of morbidity and mortality among hospitalized patients, is often due to prophylaxis failure rather than omission, but few studies have identified the risk factors for failure. Risk factors for thromboprophylaxis failure include personal or family history of VTE, use of vasopressors or inotropes, increased body mass index, cranial surgery, intensive care patient, leukocytosis, indwelling central venous catheter and admission from a long-term care facility. Identifying patients at risk for thromboprophylaxis failure should prompt close observation during hospitalization for signs of VTE, close observation after discharge and potentially more aggressive prophylaxis strategies, although no specific guidelines exist for medical patients at this time.

Reduced Anticoagulant Effect of Dabigatran in a Patient Receiving Concomitant Phenytoin.

Dabigatran, a direct thrombin inhibitor, is an oral anticoagulant indicated for the prevention of stroke in patients with atrial fibrillation (AF) and for the treatment and prevention of deep vein thrombosis and pulmonary embolism. Dabigatran, as well as the other new anticoagulants-rivaroxaban, apixaban, and edoxaban-are substrates for P-glycoprotein (P-gp). Although the U.S. labeling for rivaroxaban and apixaban states to avoid concomitant use with phenytoin, a known P-gp inducer, the U.S. labeling for dabigatran and edoxaban are less clear. We describe the first case report, to our knowledge, documenting a drug interaction between phenytoin and dabigatran by using laboratory measurements of dabigatran serum concentrations. A 45-year-old African-American man was admitted to the inpatient cardiology service following defibrillations from his implantable cardioverter defibrillator. The patient was evaluated and received appropriate antitachycardia pacing for atrial tachyarrhythmias for an episode of ventricular tachycardia (VT), and antiarrhythmic therapy with sotalol was initiated to reduce both his AF and VT burden. On review of the patient's medications for potential interactions, it was discovered that the patient was taking both dabigatran and phenytoin. To determine the magnitude of this drug interaction prior to making a change in his anticoagulation regimen, a dabigatran serum concentration was measured. This concentration was undetectable, indicating that phenytoin had a significant influence on dabigatran's metabolism and that this patient was at high risk for stroke. Clinicians should be aware of this interaction between phenytoin and dabigatran as well as with all other new oral anticoagulants. In patients taking phenytoin who require an anticoagulant, only warfarin should be prescribed to minimize the risk of stroke. In addition, the prescribing information for dabigatran should be updated to include other medications that result in a significant reduction in dabigatran serum concentrations, such as phenytoin.