Philemon Gukop

Protective effect of epicardial adiponectin on atrial fibrillation following cardiac surgery

OBJECTIVE Inflammation has been implicated in the pathogenesis of postoperative atrial fibrillation (AF). Adipose tissue secretes both pro-inflammatory cytokines such as interleukin-6 (IL-6) and anti-inflammatory mediators such as adiponectin. We set out to examine the association of adiponectin and IL-6, both circulating and locally produced by the epicardial adipose tissue, with AF development after cardiac surgery. METHODS A total of 90 consecutive patients undergoing cardiac surgery were evaluated. Blood samples were collected before induction of anaesthesia. Epicardial fat was obtained upon commencement of cardiopulmonary bypass. IL-6 and adiponectin levels were determined in serum and supernatant of epicardial adipose tissue organ cultures with two-site enzyme-linked immunosorbent assay (ELISA). Heart rhythm was assessed with continuous tele-monitoring for 72 h postoperatively, and with 6-hourly clinical examinations and daily electrocardiograms (ECGs) thereafter. RESULTS A total of 36 patients developed postoperative AF (40%). Baseline-serum IL-6 and adiponectin were not associated with AF (p = 0.86 and 0.95, respectively). Epicardial adipose tissue IL-6 levels did not correlate with the development of the arrhythmia either (p = 0.37). However, epicardial adiponectin release was lower in patients who developed AF than in those who remained in sinus rhythm (76 (interquartile range (IQR) 35-98) vs 53 ((IQR) 35-69) ng h(-1)g(-1) of tissue cultured, p = 0.066). Following linear regression, the association of epicardial adiponectin with AF almost reached statistical significance (p = 0.066). Multivariate logistic regression analysis of identified risk factors for AF, with the inclusion of epicardial adiponectin as an independent variable, revealed increased age (odds ratio (OR) 1.09, 95% confidence interval (CI) 1.02-1.17, p = 0.013) and epicardial adiponectin levels (OR 0.98, 95% CI 0.97-1.00, p = 0.054) as independent predictors of postoperative AF. CONCLUSIONS Increased epicardial adiponectin is associated with maintenance of sinus rhythm following cardiac surgery. This reinforces the inflammatory hypothesis in the pathogenesis of postoperative AF and may represent a novel therapeutic target for its effective prevention.

Antioxidant vitamins in the prevention of atrial fibrillation: what is the evidence?

Atrial fibrillation (AF) is the most common sustained arrhythmia that is associated with significant morbidity and mortality. Current available therapies remain inadequate in symptom control and secondary prevention and are often associated with significant side effects. The mechanisms underlying the pathogenesis of AF are poorly understood, although electrophysiological remodeling has been described as an important initiating step. Recently, increasing evidence implicates oxidative stress and inflammation in the pathogenesis of AF. We searched the literature for evidence to support the use of antioxidant vitamins C and E in the prevention of AF. These vitamins, through their reactive-oxygen-species- (ROS-) scavenging effect, have shown a role in AF prevention in both animal and small clinical studies. The available evidence, however, is currently insufficient to support recommendations for their use in the wider patient population. Larger-scale clinical studies are required to confirm these preliminary results. Research is also required to further the understanding of the processes involved in the pathogenesis of AF and the role of antioxidant therapies to prevent the arrhythmia.

Kawasaki disease presenting as cardiac tamponade with ruptured giant aneurysm of the right coronary artery

We report a case of a 22-year-old man with Kawasaki disease presenting with features of cardiac tamponade following rupture of giant aneurysm of his right coronary artery. He underwent an emergency operation. Aneurysmal sac was of size 4x4 cm. The entry point of the aneurysm was sutured. Right coronary artery was grafted with left radial artery. He had an uneventful recovery in the postoperative period.

Ruptured saphenous vein graft aneurysm

Ruptured saphenous vein graft (SVG) aneurysm is a rare source of significant morbidity and mortality. SVG is a common technique of coronary artery bypass grafting (CABG), but vein graft aneurysm and ruptured SVG aneurysm have not received the required attention as only few case reports exist. We present the case of a 50-year old man with ruptured vein graft aneurysm who had significant postoperative complications following surgery, and outline some preventive/management strategies.

Who might benefit from early aspirin after coronary artery surgery

A best evidence topic in cardiac surgery was written according to a structured protocol. The question addressed was whether early administration of aspirin might optimize vein graft patency. More than 250 papers were found using the reported search, of which 4 new papers in addition to the previous 7 represented the best evidence to answer the clinical question. The authors, journal, date and country of publication, patient group studied, study type, relevant outcomes and results of these papers are tabulated. Early postoperative aspirin administered within 6 h following coronary artery bypass grafting (CABG) has been shown to be optimal for prevention of vein graft occlusion. Early aspirin has significant benefit in reducing vein graft occlusion, mortality, myocardial infarction, stroke, renal failure and bowel infarction. The efficacy of early postoperative aspirin on vein graft patency diminishes the later it is administered. It has optimal benefit at 6 h, some benefit at 24 h and no benefit after 48 h post CABG. ACC/AHA, EACTS and ACCP have issued guidelines recommending administration of early aspirin or an alternative (clopidogrel, ticlopidine and indobufen) at 6 h or soon after bleeding has settled as the standard of care for optimization of vein graft patency. The ACCP guideline has also suggested that optimal prevention of cardiovascular complication should have higher value than prevention of postoperative bleeding. Several randomized, controlled studies, including a meta-analysis, have shown that early administration of aspirin following CABG is not associated with increased blood loss or transfusion requirement. Postoperative bleeding has been identified as a significant reason for non administration of early aspirin in a prospective study. It is essential to define/quantify the postoperative blood loss that precludes administration of early aspirin. This will enhance prompt administration in some cases and guide judgement, especially in patients with high-risk factors for vein graft thrombosis. Administration at 6 h is the optimal time to give aspirin as long as bleeding has settled.

Leiomyosarcoma of Pulmonary Vein Presenting as Left Atrial Mass: An Outline of Management Principles

Leiomyosarcoma of the pulmonary vein is rare and has poor prognosis. Its clinical features are nonspecific and mimic benign conditions. Early diagnosis is challenging. Most cases have been diagnosed only at autopsy or on postoperative histology specimens. Treatment is essentially palliative complete surgical excision. We outline the principles of management with the case of a 39-year-old man with leiomyosarcoma of the left pulmonary veins extending into the left atrium. Extensive investigation to achieve early diagnosis and determine extent of disease is essential. Frozen section guided adequate excision of all cardiac tumours and resection of involved lung tissue achieve local disease control. Adjuvant chemoradiotherapy has been shown to enhance survival.

Emergency management of heat exchanger leak on cardiopulmonary bypass with hypothermia.

Heat exchanger leak on cardiopulmonary bypass is very rare, but serious. The exact incidence is not known. It is an emergency associated with the potential risk of blood contamination, air embolism and haemolysis, difficulty with re-warming, acidosis, subsequent septic shock, multi-organ failure and death. We present a prompt, highly co-ordinated algorithm for the successful management of this important rare complication. There is need for further research to look for safety devices that detect leaks and techniques to reduce bacterial load. It is essential that teams practice oxygenator change-out routines and have a well-established change-out protocol.

Approximation of papillary muscles for ischaemic mitral regurgitation combined with coronary artery bypass grafting and left ventricular aneurysmectomy: a case report.

A 72-year-old female presented with severe ischaemic mitral regurgitation following a recent myocardial infarction. She had no significant past medical history. Pre-operative echocardiogram assessment demonstrated preserved tendinous cords of the mitral leaflets, a mitral valve annulus measuring 3.2 cm with end systolic coaptation of 0.3 cm, impaired left ventricular function with an ejection fraction of 35% and significant ventricular dilatation. Cardiac magnetic resonance imaging (MRI) showed delayed enhancement in the anterolateral, septal and lateral walls and confirmed the impairment of the left ventricle and a large aneurysmal deformation. On-table transoesophageal echo showed that the distance between the two papillary muscles was over 4 cm. We performed coronary artery bypass grafting combined with a Dor Procedure and papillary muscle approximation using a polytetrafluoroethylene (PTFE) vascular graft as a sling, without the insertion of a mitral annuloplasty ring. Postoperative echo and cardiac MRI showed improved left ventricular systolic function and reduced left ventricle volume associated with mild mitral regurgitation. We conclude that papillary muscles approximation as a method of mitral valve repair is a very effective procedure for functional ischaemic mitral regurgitation.

Omental Herniation: A Rare Complication of Vacuum-Assisted Closure of Infected Sternotomy Wound

Vacuum-assisted closure (VAC) has recently been adopted as an acceptable modality for management of sternotomy wound infections. Although generally efficacious, the use of negative pressure devices has been associated with complications such as bleeding, retention of sponge, and empyema. We report the first case of greater omental hernia as a rare complication of vacuum-assisted closure of sternal wound infection following coronary artery bypass grafting.