Is it safe to stop anticoagulants after successful surgery for atrial fibrillation?

A best evidence topic in cardiothoracic surgery was written according to a structured protocol. The question addressed was: is it safe to stop anticoagulants after successful surgery for atrial fibrillation? Altogether, 177 papers were found using the reported search, of which 14 were selected that represented the best evidence to answer the clinical question. Selection criteria included study relevance, primary outcome, size of study population and length of follow-up. The authors, journal, date and country of publication, patient group studied, study type, relevant outcomes and results of these papers are tabulated. The weight of evidence, including over 10,000 patient-years of follow-up, supports the discontinuation of warfarin following atrial fibrillation correction procedures as being safe, with an associated annual thromboembolic stroke rate of 0-3.8% off warfarin, in studies where warfarin was stopped at a mean of 3.6 months (range 0-8 months) after the procedure. However, the confidence of this conclusion suffers from a paucity of high-quality randomized controlled trials in the field, with the main body of evidence coming instead from observational non-randomized studies. The stroke rate also varies with the exact procedure performed; pulmonary vein isolation procedures are the most extensively evaluated and carry the lowest stroke rate following warfarin discontinuation (0-0.4% per annum when performed as an isolated procedure). By contrast, left atrial appendage occlusion by insertion of a transcatheter device has an associated annual stroke rate of 0-3.8% off warfarin. Thus, discontinuation of warfarin following such transcatheter procedures cannot be recommended at this time. Concomitant heart surgeries, such as mitral valve repair have been shown to increase the thromboembolic rate both unpredictably and dramatically, and this review thus identifies concomitant mitral valve surgery as a potentially substantial risk factor for late thromboembolic stroke in patients undergoing corrective surgeries for atrial fibrillation. This review finds in favour of warfarin discontinuation in selected patients at three months post-procedure, emphasizing consideration of the patient's individual risk-factor profile as paramount. This recommendation is in line with the 2010 guidelines for the management of atrial fibrillation produced by the European Society of Cardiology.     

Is there a role for prophylaxis against atrial fibrillation for patients undergoing lung surgery?

A best evidence topic in thoracic surgery was written according to a structured protocol. The question addressed whether prophylactic anti-arrhythmic drugs may prevent atrial fibrillation (AF) following lung resection. Altogether 457 papers were found using the reported search, of which 14 presented the best evidence to answer the clinical question. The author, journal, date and country of publication, patient group studied, study type, relevant outcomes, results and study weaknesses of these papers are tabulated. We identified single randomized trials that have demonstrated a benefit for Diltiazem, Bupivacaine epidural and magnesium for prophylaxis against AF in patients undergoing non-cardiac thoracic surgery, with a number needed to treat of between 4 and 8 with these regimes.     

Is bisphosphonate-associated osteonecrosis of the jaw caused by soft tissue toxicity?

Osteonecrosis of the jaw (ONJ) is a complication of high-dose bisphosphonate use, characterized by the finding of exposed bone in the oral cavity. It has been assumed that the primary lesion lies in bone and is related to over-suppression of bone turnover, but it is unclear why such a lesion should present with loss of the soft tissue covering of the mandible or maxilla as the primary clinical feature. A possible explanation of this paradox is that bisphosphonate is accumulated in bone in concentrations sufficient to be directly toxic to the oral epithelium. This would result in the failure of healing of soft tissue lesions (such as those caused by invasive dental procedures or by subclinical trauma from dentures) leading to secondary infection of the underlying bone. This model would explain why bone resection is unhelpful in managing this problem, suggests that low bone turnover caused by non-bisphosphonate drugs should not cause the same problem, and raises the possibility that agents which reverse bisphosphonate effects in vitro might have a role in the management of ONJ.     

Is Dupuytren's disease caused by an imbalance between proliferation and cell death?

Dupuytren's contracture shares certain properties with malignant tumours, characterized by proliferation and lack of apoptosis, which may be induced by the c-myc oncogene. Because of these similarities, the relationship between the c-myc oncogene expression, bcl-2 oncogene (anti-apoptotic gene) and proliferation was investigated in Dupuytren's disease. Proliferation was assessed by immunohistochemical staining of the mib-1 antibody. Results were compared with those from fibrosarcoma specimens, representing a related malignant tumour. Non-diseased fascia from Dupuytren patients and flexor retinaculum from patients undergoing carpal tunnel release without Dupuytren's disease were used as controls. Expression of c-myc was elevated in primary Dupuytren's disease and fibrosarcoma specimens, whilst recurrent Dupuytren's disease, non-diseased Dupuytren fascia and flexor retinaculum exhibited significantly lower levels. Neither bcl-2 nor mib-1 were detected in Dupuytren's disease, non-diseased fascia or flexor retinaculum, in contrast to fibrosarcoma. The imbalance between proliferation and apoptosis, producing malignant growth was thus confirmed for fibrosarcoma, but not for Dupuytren's disease.     

Does a concomitant Cox-maze procedure improve survival in atrial fibrillation?

In this review paper, the authors briefly describe the pathophysiology of atrial fibrillation. The original technique to restore sinus rhythm is cited, with its subsequent technical variations. A literature review summarizes the outcome of patients who benefited from the Cox-MAZE procedure.     

Is antero-posterior position superior to antero-lateral position for placement of electrodes for external cardioversion of atrial fibrillation?

A best evidence topic in cardiac surgery was written according to a structured protocol. The question addressed was whether the antero-posterior position is superior to the antero-lateral position for the placement of electrodes for cardioversion of atrial fibrillation. Altogether 167 papers were found using the reported search, of which 5 presented the best evidence to answer the clinical question. The author, journal, date and country of publication, patient group studied, study type, relevant outcomes, results, and study weaknesses of these papers are tabulated. We conclude that there is no clinical difference between the two positions although if one position fails to convert the patient, the alternative position may still achieve success.