Risk-adjusted survival after coronary artery bypass grafting: implications for quality improvement.

Mortality represents an important outcome measure following coronary artery bypass grafting. Shorter survival times may reflect poor surgical quality and an increased number of costly postoperative complications. Quality control efforts aimed at increasing survival times may be misleading if not properly adjusted for case-mix severity. This paper demonstrates how to construct and cross-validate efficiency-outcome plots for a specified time (e.g., 6-month and 1-year survival) after coronary artery bypass grafting, accounting for baseline cardiovascular risk factors. The application of this approach to regional centers allows for the localization of risk stratification rather than applying overly broad and non-specific models to their patient populations.

Coil embolization of persistent false lumen after type A dissection repair.

A 44-year-old man with a type A dissection repair 5 years earlier presented with progressive enlargement of the residual arch and thoracic aorta. Flow into the false lumen from the distal aortic suture line was evident on contrast-enhanced computed tomography. Through a redo hemisternotomy, the false lumen was accessed directly. An Amplatzer plug was deployed within the narrowed neck of the false lumen proximal to the enlarged false lumen within descending aorta. Interlocking coils were deployed proximal to the Amplatzer plug, resulting in thrombosis of the false lumen.

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.

The impact of race and postoperative atrial fibrillation on operative mortality after elective coronary artery bypass grafting.

OBJECTIVE: Black patients are less likely to develop postoperative atrial fibrillation (POAF) following coronary artery bypass grafting (CABG) than whites. However, the influence of race and POAF on operative mortality has not been examined. The objective of this study was to determine the influence of race and POAF on operative mortality after CABG. METHODS: Patients undergoing elective CABG between 1992 and 2011 were included. Operative mortality was compared between patients with and those without new-onset POAF by race. Relative risk (RR) and 95% confidence intervals (CI) were computed using Poisson (robust variance estimates) and log-binomial regression models. RESULTS: A total of 1215 (23%) patients developed POAF (white n=1060; black n=155) following CABG (N=5387). Operative mortality differed by POAF status within race category (white POAF: adjusted RR=1.4, 95% CI=0.86-2.2; black POAF: adjusted RR=5.0, 95% CI=1.9-13; Pinteraction=0.0016). Black POAF patients had a 2-fold increased risk of operative death compared with white POAF patients (Padjusted=0.052). CONCLUSION: POAF was observed to be a stronger predictor of operative mortality in black compared with white patients undergoing elective CABG.

The effect of preoperative ß-blocker use and race on long-term survival after coronary artery bypass grafting.

OBJECTIVE: To date, racial differences in the long-term survival of coronary artery bypass grafting (CABG) patients who receive preoperative ß-blockers have not been specifically examined. The purpose of this study was to examine the effect of preoperative ß-blockers on long-term survival among black CABG patients and to compare the magnitude of this effect with white patients. DESIGN: A retrospective cohort study. SETTING: A tertiary referral heart hospital. PARTICIPANTS: 13,354 patients undergoing CABG between 1992 and 2011. MEASUREMENTS AND MAIN RESULTS: Hazard ratios (HR) and 95% confidence intervals (CI) were computed using a Cox regression model. A total of 1,448 (62%) black and 6,094 (55%) white patients had a history of preoperative ß-blocker use. Among black patients, those receiving ß-blockers survived longer than those not receiving ß-blockers (adjusted HR = 0.77, 95% CI = 0.67-0.88). The survival advantage was comparable to that observed among white patients (adjusted HR = 0.88, 95% CI = 0.82-0.93). CONCLUSION: Black CABG patients benefited from preoperative ß-blockers and the magnitude of the effect was comparable to that among white patients.

Race and survival among diabetic patients after coronary artery bypass grafting.

BACKGROUND: Diabetes is a known predictor of decreased long-term survival after coronary artery bypass grafting (CABG). Differences in survival by race have not been examined. METHODS: A retrospective cohort study was conducted for CABG patients between 1992 and 2011. Long-term survival was compared in patients with and without diabetes and stratified by race. Hazard ratios (HR) and 95% confidence intervals (CI) were computed using a Cox regression model. RESULTS: Out of the 13,053 patients undergoing CABG, 35% (black n = 1,655; white n = 2,884) had diabetes at the time of surgery. The median follow-up for study participants was 8.2 years. Long-term survival after CABG was similar between black and white diabetic patients (no diabetes, HR = 1.0; white diabetic patients, adjusted HR = 1.5, 95%CI = 1.4-1.6; black diabetic patients, adjusted HR = 1.5, 95%CI = 1.4-1.7). CONCLUSION: A survival disadvantage after CABG was not observed among black versus white diabetic patients in our study.

Racial differences in survival among hemodialysis patients after coronary artery bypass grafting.

The aim of this study was to examine racial differences in long-term survival among hemodialysis patients after coronary artery bypass grafting (CABG). To our knowledge this has not been previously addressed in the literature. Black and white hemodialysis patients undergoing first-time, isolated CABG procedures between 1992 and 2011 were compared. Survival probabilities were computed using the Kaplan-Meier product-limit method and stratified by race. Hazard ratios (HR) and 95% confidence intervals (CI) were computed using a Cox regression model. A total of 207 (2%) patients were on hemodialysis at the time of CABG. White (n = 80) hemodialysis patients had significantly decreased 5-year survival compared with black (n = 127) patients (adjusted HR = 1.9, 95% CI = 1.2-2.8). Our finding provides useful outcome information for surgeons, primary care providers, and their patients.

The effect of race and chronic obstructive pulmonary disease on long-term survival after coronary artery bypass grafting.

BACKGROUND: Chronic obstructive pulmonary disease (COPD) is a known predictor of decreased long-term survival after coronary artery bypass grafting (CABG). Differences in survival by race have not been examined. METHODS: A retrospective cohort study was conducted of CABG patients between 2002 and 2011. Long-term survival was compared in patients with and without COPD and stratified by race. Hazard ratios (HR) and 95% confidence intervals (CI) were computed using a Cox regression model. RESULTS: A total of 984 (20%) patients had COPD (black n = 182; white n = 802) at the time of CABG (N = 4,801).The median follow-up for study participants was 4.4 years. COPD was observed to be a statistically significant predictor of decreased survival independent of race following CABG (no COPD: HR = 1.0; white COPD: adjusted HR = 1.9, 95% CI = 1.7-2.3; black COPD: adjusted HR = 1.6, 95% CI = 1.1-2.2). CONCLUSION: Contrary to the expected increased risk of mortality among black COPD patients in the general population, a similar survival disadvantage was not observed in our CABG population.

Preoperative atrial fibrillation and long-term survival after open heart surgery in a rural tertiary heart institute.

BACKGROUND: Preoperative atrial fibrillation (AF) is associated with increased morbidity and mortality after open heart surgery. However, the impact of preoperative AF on long-term survival after open heart surgery has not been widely examined in rural populations. Patients from rural regions are less likely to receive treatment for cardiac conditions and to have adequate medical insurance coverage. OBJECTIVE: To examine the influence of preoperative AF on long-term survival following open heart surgery in rural eastern North Carolina. METHODS: Long-term survival was compared in patients with and without preoperative AF after coronary artery bypass grafting (CABG) and CABG plus valve (CABG + V) surgery between 2002 and 2011. Hazard ratios (HR) and 95% confidence intervals (CI) were computed using a Cox regression model. RESULTS: The study population consisted of 5438 patients. A total of 263 (5%) patients had preoperative AF. Preoperative AF was an independent predictor of long-term survival (open heart surgery: adjusted HR = 1.6, 95% CI = 1.3-2.0; CABG: adjusted HR = 1.6, 95% CI = 1.3-2.1; CABG + V: adjusted HR = 1.6, 95% CI = 1.1-2.3). CONCLUSION: Preoperative AF is an important predictor of long-term survival after open heart surgery in this rural population.

Impact of race and postoperative atrial fibrillation on long-term survival after coronary artery bypass grafting.

BACKGROUND AND AIM: Postoperative atrial fibrillation (POAF) is a known predictor of in-hospital morbidity and short-term survival after coronary artery bypass grafting (CABG). The impact of race and long-term survival has not been examined in this population. We aimed to examine the influence of these factors on long-term survival in patients undergoing CABG. METHODS: Patients undergoing first-time, isolated CABG between 1992 and 2011 were included in this study. Long-term survival was compared in patients with and without POAF and stratified by race. Hazard ratios (HR) and 95% confidence intervals (CI) were computed using a Cox regression model. RESULTS: A total of 2,907 (22%) patients developed POAF (black n=370; white n=2,537) following CABG (N=13,165). Median follow-up for study participants was 8.2 years. Long-term survival after CABG differed by POAF status and race (no POAF: HR=1.0; white POAF: adjusted HR=1.1, 95% CI=1.06-1.2; black POAF: adjusted HR=1.4, 95% CI=1.2-1.6; pTrend=0.0002). lack POAF patients also died sooner after surgery than their white counterparts (adjusted HR=1.2, 95% CI=1.02-1.4). CONCLUSION: Black race was a statistically significant predictor of decreased survival among POAF patients after CABG. This finding provides useful outcome information for surgeons and their patients.

The impact of prior percutaneous coronary intervention on long-term survival after coronary artery bypass grafting.

BACKGROUND: Previous studies examining the influence of prior percutaneous coronary intervention (PCI) on long-term survival after coronary artery bypass grafting (CABG) have reported conflicting results. The purpose of this study was to further examine the influence of prior PCI on long-term survival after CABG at a large tertiary referral heart institute. METHODS: Long-term survival between 1992 and 2011 was compared in non-emergent CABG cases with and without prior PCI. Hazard ratios (HR) and 95% confidence intervals (CI) were computed using a Cox regression model. RESULTS: A total of 2532 (19%) patients had prior PCI before CABG (n=13,354). The median follow-up for study participants was 8.1 years. The median survival for patients with and without prior PCI was 15 years and 14 years, respectively (p<0.0001). Long-term survival was similar between patients with and without prior PCI after adjusting for age, sex, race, hypertension, coronary artery disease severity, congestive heart failure, and prior stroke (adjusted HR=0.99, 95%CI=0.91-1.06). CONCLUSION: Findings from outcomes research are important in the planning of appropriate postoperative patient care. Our study provides additional evidence that prior PCI is not a significant predictor of long-term survival after CABG.

Implications of Hemodialysis in Patients Undergoing Coronary Artery Bypass Grafting.

BACKGROUND: Cardiovascular disease is the leading cause of morbidity and mortality in patients on hemodialysis. To our knowledge, no studies have examined long-term outcomes of hemodialysis patients following coronary artery bypass grafting (CABG) in a predominately rural, low-income, and racially dichotomous population. METHODS: Long-term survival of hemodialysis patients undergoing non-emergent, isolated CABG was compared with non-hemodialysis patients. Survival probabilities were computed using the Kaplan-Meier product limit method and stratified by hemodialysis. Hazard ratios (HR) and 95% confidence intervals (95%CI) were computed using a Cox regression model. RESULTS: Hemodialysis patients (n=220) had shorter long-term survival than non-hemodialysis patients (median survival=3.3 versus 14 years, p<0.0001). The survival difference remained statistically significant after adjusting for clinically relevant variables (HR=5.2, 95%CI=4.4-6.2). CONCLUSION: Hemodialysis patients had significantly shorter long-term survival compared with non-hemodialysis patients after CABG. Further research is needed to address the cost and policy implications of our findings, especially among priority populations.

Delayed left ventricle-to-right atrial fistula following aortic valve replacement.

Fistula development between the left ventricular outflow tract and right atrium is a rare complication of aortic valve replacement (AVR), typically seen with calcific aortic stenosis or endocarditis. The case is reported of a left ventricle-to-right atrial fistula following mechanical AVR for aortic insufficiency.

Three-dimensional echocardiographic features of unicuspid aortic valve stenosis correlate with surgical findings.

A unicuspid aortic valve (UAV) is a rare congenital defect that may manifest clinically as severe aortic stenosis or regurgitation in the third to fifth decade of life. This report describes two cases of UAV stenosis in adult patients diagnosed by transesophageal echocardiography (TEE). The utility of three-dimensional TEE in confirming valve morphology and its relevance to transcatheter valve replacement are discussed.

An acute animal model of aortic stenosis: initial attempts at leaflet modification.

BACKGROUND AND AIM OF THE STUDY: Percutaneous valve insertion is an emerging treatment for aortic stenosis (AS). To date, no large animal model exists that replicates human calcific AS; moreover, the absence of any valve pathology in currently available animal models prevents their use in any realistic assessment of percutaneous aortic valve therapy. Hence, the aim of the present study was to create an acute large animal model in which human calcific AS could be simulated. METHODS: Ten domestic swine underwent open-heart surgery utilizing cardiopulmonary bypass (CPB) and cardioplegic arrest. The aortic valve annulus and leaflets were injected with cyanoacrylate, after which epicardial echocardiography was used to assess the creation of AS. At the time of animal sacrifice, the hearts were harvested for gross and histopathological examination. RESULTS: The leaflet and annular injections were performed successfully in all animals. Subsequently, seven animals were weaned from CPB and underwent post procedural echocardiographic evaluations, whereby the treated valves were harvested for gross and histological examination. CONCLUSION: Cyanoacrylate can be injected into the porcine aortic valve and annulus to create a model that resembles human calcific AS in the acute setting. Additional long-term follow up studies must be conducted, however, before this model can be utilized in the development of percutaneous valve therapy.

Coronary surgery in a hemophiliac with continuous factor VIII replacement.

In the past, hemophiliacs rarely underwent cardiac surgery because of limited lifespan. As blood transfusions have become safer, hemophiliacs are living longer and becoming more susceptible to diseases that afflict the elderly, such as coronary atherosclerosis. We describe the hematologic management of a patient with hemophilia A who underwent coronary artery bypass surgery.

Increased propensity for cell death in diabetic human heart is mediated by mitochondrial-dependent pathways.

Progressive energy deficiency and loss of cardiomyocyte numbers are two prominent factors that lead to heart failure in experimental models. Signals that mediate cardiomyocyte cell death have been suggested to come from both extrinsic (e.g., cytokines) and intrinsic (e.g., mitochondria) sources, but the evidence supporting these mechanisms remains unclear, and virtually nonexistent in humans. In this study, we investigated the sensitivity of the mitochondrial permeability transition pore (mPTP) to calcium (Ca(2+)) using permeabilized myofibers of right atrium obtained from diabetic (n = 9) and nondiabetic (n = 12) patients with coronary artery disease undergoing nonemergent coronary revascularization surgery. Under conditions that mimic the energetic state of the heart in vivo (pyruvate, glutamate, malate, and 100 µM ADP), cardiac mitochondria from diabetic patients show an increased sensitivity to Ca(2+)-induced mPTP opening compared with nondiabetic patients. This increased mPTP Ca(2+) sensitivity in diabetic heart mitochondria is accompanied by a substantially greater rate of mitochondrial H(2)O(2) emission under identical conditions, despite no differences in respiratory capacity under these conditions or mitochondrial enzyme content. Activity of the intrinsic apoptosis pathway mediator caspase-9 was greater in diabetic atrial tissue, whereas activity of the extrinsic pathway mediator caspase-8 was unchanged between groups. Furthermore, caspase-3 activity was not significantly increased in diabetic atrial tissue. These data collectively suggest that the myocardium in diabetic patients has a greater overall propensity for mitochondrial-dependent cell death, possibly as a result of metabolic stress-imposed changes that have occurred within the mitochondria, rendering them more susceptible to insults such as Ca(2+) overload. In addition, they lend further support to the notion that mitochondria represent a viable target for future therapies directed at ameliorating heart failure and other comorbidities that come with diabetes.

Blunt coronary injury presenting as massive left-sided hemothorax.

Hemothorax after blunt trauma results from injury to intrathoracic structures or the chest wall. Tube thoracostomy is the most common mode of treatment; depending on the type of injury, it is frequently the only intervention required. Rarely, blunt cardiac injury can produce hemothorax if a communication exists between the pericardium and pleural space. We describe such a case that highlights the importance of a broad differential diagnosis when treating acutely injured patients.

Substrate-specific derangements in mitochondrial metabolism and redox balance in the atrium of the type 2 diabetic human heart.

OBJECTIVES: The aim of this study was to determine the impact of diabetes on oxidant balance and mitochondrial metabolism of carbohydrate- and lipid-based substrates in myocardium of type 2 diabetic patients. BACKGROUND: Heart failure represents a major cause of death among diabetic patients. It has been proposed that derangements in cardiac metabolism and oxidative stress may underlie the progression of this comorbidity, but scarce evidence exists in support of this mechanism in humans. METHODS: Mitochondrial oxygen (O(2)) consumption and hydrogen peroxide (H(2)O(2)) emission were measured in permeabilized myofibers prepared from samples of the right atrial appendage obtained from nondiabetic (n = 13) and diabetic (n = 11) patients undergoing nonemergent coronary artery bypass graft surgery. RESULTS: Mitochondria in atrial tissue of type 2 diabetic individuals show a sharply decreased capacity for glutamate and fatty acid-supported respiration, in addition to an increased content of myocardial triglycerides, as compared to nondiabetic patients. Furthermore, diabetic patients show an increased mitochondrial H(2)O(2) emission during oxidation of carbohydrate- and lipid-based substrates, depleted glutathione, and evidence of persistent oxidative stress in their atrial tissue. CONCLUSIONS: These findings are the first to directly investigate the effects of type 2 diabetes on a panoply of mitochondrial functions in the human myocardium using cellular and molecular approaches, and they show that mitochondria in diabetic human hearts have specific impairments in maximal capacity to oxidize fatty acids and glutamate, yet increased mitochondrial H(2)O(2) emission, providing insight into the role of mitochondrial dysfunction and oxidative stress in the pathogenesis of heart failure in diabetic patients.

Advances in mitral valve repair.

The results of mitral valve repair for structural disease are durable and are generally accepted to be superior to mitral valve replacement. Following the early pioneering work of Carpentier, most advances in mitral repair have involved performing the same repair through ever smaller incisions in hopes of minimizing tissue trauma. Mitral repair is now possible thru port access with videoscopic and robotic assistance. Transcatheter repair techniques are now being investigated and offer the possibility of mitral repair without the utilization of cardiopulmonary bypass.