Plasma Catecholamine Levels on the Morning of Surgery Predict Post-Operative Atrial Fibrillation.

OBJECTIVES: This study sought to determine whether plasma catecholamines and monoamine oxidase-B (MOA-B) are associated with post-operative atrial fibrillation (POAF) in patients undergoing elective cardiac surgery. BACKGROUND: Although intra- and post-operative adrenergic tone has been demonstrated to be an causative factor for POAF, the role and association of pre-operative plasma catecholamines remains unclear. METHODS: Prior to administration of anesthesia on the morning of surgery, blood samples were obtained from 324 patients undergoing nonemergent coronary artery bypass graft and/or aortic valve surgery with cardiopulmonary bypass at East Carolina Heart Institute. The concentrations of norepinephrine (NE), dopamine (DA), epinephrine (EPI), and enzyme MAO-B were assessed in platelet-rich plasma. A log-binomial regression model was used to determine the association between quartiles of these variables and POAF. RESULTS: Levels of NE (p = 0.0006) and EPI (p = 0.047) in the 4th quartile [Formula: see text] were positively associated with POAF, whereas DA (p = 0.0034) levels in the 4th quartile [Formula: see text] were inversely associated with POAF. Adjusting for age, heart failure (HF), and history of atrial fibrillation, the composite pre-operative (adrenergic) plasma marker [Formula: see text] was associated with a 4-fold increased occurrence of POAF (adjusted p = 0.0001). No association between plasma MAO-B and POAF was observed. CONCLUSIONS: Our results suggest that pre-operative adrenergic tone is an important factor underlying POAF. This information provides evidence that assessment of plasma catecholamines may be a low-cost method that is easy to implement for predicting which patients are likely to develop POAF. More investigation in a multicentric setting is needed to validate our results.

Monoamine oxidase is a major determinant of redox balance in human atrial myocardium and is associated with postoperative atrial fibrillation.

BACKGROUND: Onset of postoperative atrial fibrillation (POAF) is a common and costly complication of heart surgery despite major improvements in surgical technique and quality of patient care. The etiology of POAF, and the ability of clinicians to identify and therapeutically target high-risk patients, remains elusive. METHODS AND RESULTS: Myocardial tissue dissected from right atrial appendage (RAA) was obtained from 244 patients undergoing cardiac surgery. Reactive oxygen species (ROS) generation from multiple sources was assessed in this tissue, along with total glutathione (GSHt) and its related enzymes GSH-peroxidase (GPx) and GSH-reductase (GR). Monoamine oxidase (MAO) and NADPH oxidase were observed to generate ROS at rates 10-fold greater than intact, coupled mitochondria. POAF risk was significantly associated with MAO activity (Quartile 1 [Q1]: adjusted relative risk [ARR]=1.0; Q2: ARR=1.8, 95% confidence interval [CI]=0.84 to 4.0; Q3: ARR=2.1, 95% CI=0.99 to 4.3; Q4: ARR=3.8, 95% CI=1.9 to 7.5; adjusted Ptrend=0.009). In contrast, myocardial GSHt was inversely associated with POAF (Quartile 1 [Q1]: adjusted relative risk [ARR]=1.0; Q2: ARR=0.93, 95% confidence interval [CI]=0.60 to 1.4; Q3: ARR=0.62, 95% CI=0.36 to 1.1; Q4: ARR=0.56, 95% CI=0.34 to 0.93; adjusted Ptrend=0.014). GPx also was significantly associated with POAF; however, a linear trend for risk was not observed across increasing levels of the enzyme. GR was not associated with POAF risk. CONCLUSIONS: Our results show that MAO is an important determinant of redox balance in human atrial myocardium, and that this enzyme, in addition to GSHt and GPx, is associated with an increased risk for POAF. Further investigation is needed to validate MAO as a predictive biomarker for POAF, and to explore this enzyme's potential role in arrhythmogenesis.

A novel complication of bariatric surgery.

The incidence of obesity in the US is increasing. This has been associated with an increasing incidence and prevalence of diabetes, hypertension, and obstructive sleep apnea. Diet alone has generally been ineffective in attaining significant weight loss. Bariatric surgery is associated with significant weight loss and improvement in diabetes, hypertension, and obstructive sleep apnea. In this article we describe an unusual complication of bariatric surgery.

Patient preferences and National Health Service costs: a cost-consequences analysis of cancer genetic services.

The study has three aims; firstly to establish if, having been informed of their risk status and that gene testing is inappropriate for them, low and moderate risk patients have misunderstood or failed to grasp this and want a test that is inappropriate for them. Secondly, to elicit patients' willingness to pay for cancer genetic services. Thirdly, to ascertain the aspects of cancer genetics services that are important to high risk patients and present service configurations prioritised in terms of preferences accompanied by their costs (cost-consequences analysis). Patient preferences were gathered from 120 patients returning a self-administered discrete choice questionnaire issued post genetic risk assessment. Patients at low and moderate risk of developing breast cancer desired inappropriate testing. Patients at high, moderate and low risk of developing genetic cancer were willing to pay up to 3,000 pounds for genetic serviced, which exceeds the current estimated cost of providing testing and counselling. Counselling by a genetics associate accompanied by favourable levels of other attributes provided high utility and substantial cost savings.

Can we assume that research participants are utility maximisers?

The objective of this study was to experimentally examine by means of an information manipulation if respondents are adhering to the utility theory axiom of utility maximisation. A repeated measure experimental design was used. Assessments were conducted pre- and post-intervention with self-administered questionnaires. The study participants were 158 (142 after exclusions) first year undergraduate students, Bangor University (UK). The intervention-information manipulation-did not induce the hypothesised changes in the perceived pros and cons of, or desire for, genetic testing and counselling for breast cancer; correlation revealed a weak relationship between the pros and cons of and desire for testing and counselling. We conclude that there was no evidence of utility maximisation-the key tenet of utility theory-being used. Given the contradiction between the findings of this study and others, there is a need to conduct further research into utility maximisation.

Valve-sparing root replacement after prior Starr-Edwards aortic valve replacement.

Historically, patients with prior aortic valve replacements who subsequently present with an ascending aortic aneurysm require placement of a valve conduit. However, if the patient has a functional mechanical valve with proven long-term durability, an attempt can be made to preserve the intact valve and to graft the aneurysmal aortic root. The case is described of a patient with a previously placed Starr-Edwards aortic valve who subsequently developed a 6-cm ascending aortic aneurysm. By removing the valve ball and using the existing sewing ring, a proximal graft anastomosis was created with ease, eliminating valve excision.