Linda C. Kindell

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 enzymes potential role in arrhythmogenesis.

Impact of Timing and Surgical Approach on Outcomes After Mitral Valve Regurgitation Operations

BACKGROUND This study investigated whether the timing of mitral valve (MV) repair or surgical approach affects outcomes in patients with MV regurgitation. METHODS Between 1992 and 2009, 2,255 patients underwent MV operations, including 1,305 with isolated MV regurgitation operations (1,054 repairs, 251 replacements). Surgical approaches were sternotomy in 377, video-assisted right minithoracotomy in 481, or robot-assisted in 447. Mean follow-up was 6.4±4.5 years (maximum, 19 years). RESULTS Sternotomy MV repairs decreased during the study while minimally invasive MV repairs increased. Robotic MV repair patients were younger, with fewer women, had better left ventricular ejection fractions, and were more likely to have myxomatous degeneration (all p<0.001). The robotic approach led to a higher MV repair rate and increased use of leaflet/chordal procedures but had longer cardiopulmonary bypass and aortic cross-clamp times (all p<0.001). The 30-day mortality for isolated MV repair was similar for all approaches (p=0.409). Fewer neurological events were observed in the videoscopic and robotic groups (p=0.013). Adjusted survival was similar for all approaches (p=0.357). Survival in patients in New York Heart Association class I to II with myxomatous degeneration or annular dilatation was similar to a matched population but was worse for patients in class III to IV or undergoing MV replacement. CONCLUSIONS MV repair in patients with severe MV regurgitation should be performed before New York Heart Association class III to IV symptoms develop. Minimally invasive MV repair techniques render similar outcomes as the sternotomy approach.

Clinical Outcomes in Patients With Prolonged Intensive Care Unit Length of Stay After Cardiac Surgical Procedures

BACKGROUND Advances in critical care medicine have allowed for improved care of patients requiring prolonged intensive care unit length of stay (prICULOS) after cardiac operations, yet little is known regarding their eventual outcomes. The purpose of this study was to examine short- and long-term outcomes in patients undergoing cardiac operations with prICULOS. METHODS All cases of coronary artery bypass grafting (CABG), aortic valve, mitral valve, and combined CABG/valve surgical procedures performed at a single institution from July 2002 to July 2007 were identified. All-cause mortality in patients discharged alive from the hospital was determined until December 2007 through linkage with the Social Security Death Index. Patients who experienced intraoperative death or those with missing or invalid social security numbers were excluded. The definition of prICULOS was total ICULOS greater than 7 days. RESULTS A total of 3,478 patients met inclusion criteria. One hundred thirty-seven of three thousand four hundred seventy-eight patients (3.9%) experienced prICULOS. These patients were more likely to be older than 70 years (55.5% versus 30.5%; p<0.0001) and to have had recent myocardial infarction (28.5% versus 20.1%; p=0.02), previous cardiac operation (18.3% versus 6.9%; p<0.0001), and emergent status (9.5% versus 1.6%; p<0.0001). They experienced greater in-hospital mortality (37.2% versus 1.7%; p<0.0001) and those who were discharged alive had worse long-term survival (log-rank, p<0.0001). After risk adjustment, prICULOS emerged as a significant predictor of in-hospital death (odds ratio [OR] 20.9; 95% confidence interval [CI], 12.9-33.7) and decreased long-term survival (hazard ratio [HR] 2.9; 95% CI, 2.0-4.3). CONCLUSIONS Patients with prICULOS after cardiac operations have worse overall outcomes. These data may be used to inform these patients and their families of realistic expectations regarding their clinical course.

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.

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.

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.

Increased coronary artery disease severity in black women undergoing coronary bypass surgery.

AbstractRace and sex disparities are believed to play an important role in heart disease. The purpose of this study was to examine the association between race, sex, and number of diseased vessels at the time of coronary artery bypass grafting (CABG), and subsequent postoperative outcomes.The 13,774 patients undergoing first-time, isolated CABG between 1992 and 2011 were included. Trend in the number of diseased vessels between black and white patients, stratified by sex, were analyzed using a Cochran–Armitage trend test. Models were adjusted for age, procedural status (elective vs. nonelective), and payor type (private vs. nonprivate insurance).Black female CABG patients presented with an increasingly greater number of diseased vessels than white female CABG patients (adjusted Ptrend = 0.0021). A similar trend was not observed between black and white male CABG patients (adjusted Ptrend = 0.18). Black female CABG patients were also more likely to have longer intensive care unit and hospital lengths of stay than other race–sex groups.Our findings suggest that black female CABG patients have more advanced coronary artery disease than white female CABG patients. Further research is needed to determine the benefit of targeted preventive care and preoperative workup for this high-risk group.

Perioperative Inotrope Therapy and Atrial Fibrillation Following Coronary Artery Bypass Graft Surgery: Evidence of a Racial Disparity

Following coronary artery bypass graft (CABG) surgery, mortality rates are significantly higher among black patients who experience postoperative atrial fibrillation (POAF). Perioperative inotropic therapy (PINOT) was associated with POAF in previous reports, but the extent to which race influences this association is unknown. In the present study, the relationship between PINOT, race, and POAF was examined in patients undergoing CABG surgery.

Increased Long-Term Mortality among Black CABG Patients Receiving Preoperative Inotropic Agents

The aim of this study was to examine racial differences in long-term mortality after coronary artery bypass grafting (CABG), stratified by preoperative use of inotropic agents. Black and white patients who required preoperative inotropic support prior to undergoing CABG procedures between 1992 and 2011 were compared. Mortality probabilities were computed using the Kaplan-Meier product-limit method. Hazard ratios (HR) and 95% confidence intervals (CI) were computed using a Cox regression model. A total of 15,765 patients underwent CABG, of whom 211 received preoperative inotropic agents within 48 hours of surgery. Long-term mortality differed by race (black versus white) among preoperative inotropic category (inotropes: adjusted HR = 1.6, 95% CI = 1.009–2.4; no inotropes: adjusted HR = 1.15, 95% CI = 1.08–1.2; Pinteraction < 0.0001). Our study identified an independent preoperative risk-factor for long-term mortality among blacks receiving CABG. This outcome provides information that may be useful for surgeons, primary care providers, and their patients.

Long-Term Survival after Cardiac Surgery in Patients with Chronic Obstructive Pulmonary Disease

BACKGROUND Although many patients with chronic obstructive pulmonary disease (COPD) require a prolonged length of stay (PLOS) following coronary artery bypass grafting (CABG), the impact of PLOS on long-term survival has not been examined in this population. OBJECTIVES To determine the association between PLOS and long-term survival among COPD and non-COPD patients after CABG and to examine consequent policy and practice-based implications. METHODS A retrospective cohort study of CABG patients was conducted between 2002 and 2011. Long-term survival was compared in patients with and without COPD and stratified by PLOS. Hazard ratios (HR) and 95% confidence intervals (CI) were computed using a Cox regression model. RESULTS A total of 203 patients (4.2%) had PLOS after nonemergent CABG (N = 4801). PLOS was an important independent predictor of decreased long-term survival (no COPD, no PLOS: HR = 1.0; COPD, no PLOS: adjusted HR [95% CI], 1.8 [1.5-2.1]; no COPD, PLOS: 3.3 [2.5-4.4]; COPD, PLOS: 6.0 [4.4-8.2]; PTrend < .001). CONCLUSIONS COPD and PLOS are 2 of many factors that affect long-term mortality in postoperative CABG patients. Aggressive treatment strategies aimed at early weaning off of mechanical ventilation and prevention of reintubation among COPD patients must be considered carefully as a means to reduce length of stay after CABG. Our results also have important implications for the long-term management of these patients and strategies for containing costs over the life course of the patient.