Electrocardiographic activity before onset of postoperative atrial fibrillation in cardiac surgery patients.

BACKGROUND: Electrocardiographic (ECG) characteristics were analyzed in postoperative cardiac surgery patients in an attempt to predict development of new-onset postoperative atrial fibrillation (AF). METHODS: Nineteen ECG characteristics were analyzed using computer-based algorithms. The parameters were retrospectively analyzed from ECG signals recorded in postoperative cardiac surgery patients while they were in the cardiovascular intensive care unit (CVICU) at our institution. ECG data from 99 patients (of whom 43 developed postoperative AF) were analyzed. A bootstrap variable selection procedure was applied to select the most important ECG parameters, and a multivariable logistic regression model was developed to classify patients who did and did not develop AF. RESULTS: Premature atrial activity (PAC) was greater in AF patients (P < 0.01). Certain heart rate variability (HRV) and turbulence parameters also differed in patients who did and did not develop AF. In contrast, P-wave morphology was similar in patients with and without AF. Receiver operating curve (ROC) analysis applied to the model produced a C-statistic of 0.904. The model thus correctly classified AF patients with more than a 90% sensitivity and a 70% specificity. CONCLUSION: Among the 19 ECG parameters analyzed, PAC activity, frequency-domain HRV, and heart rate turbulence parameters were the best discriminators for postoperative AF.

Socioeconomic status and comorbidity as predictors of preoperative quality of life in cardiac surgery.

OBJECTIVE: Preoperative quality of life of patients undergoing cardiac surgical procedures has been associated with postoperative morbidity, survival, and quality of life. Patients of lower socioeconomic status have disproportionately greater cardiovascular disease burden and more complications of cardiovascular disease. We examined the interactive effects of demographic characteristics, socioeconomic status, and comorbidity on preoperative functional quality of life measured by the well-validated cardiovascular disease-specific Duke Activity Status Index. METHODS: The patient population consisted of 5581 patients between May 1995 and January 1999 who underwent operations on cardiopulmonary bypass: isolated coronary artery bypass grafting, isolated valve procedures, or combined coronary artery bypass grafting and valve procedures and had a preoperative Duke Activity Status Index, along with socioeconomic status information from United States 2000 census data. Predictors were identified by logistic regression for maximum value of baseline DASI and linear regression for DASI scores less than maximum by means of bagging variable selection. RESULTS: Lower socioeconomic status was associated of lower risk-adjusted quality of life (maximum Duke Activity Status Index P = .0002, less than maximum Duke Activity Status Index P = .0007). Older age, female sex, certain comorbidities, higher New York Heart Association class, lower left ventricular function, and reoperation were also statistically significantly associated with lower preoperative Duke Activity Status Index. CONCLUSION: Lower socioeconomic status is associated with lower risk-adjusted quality of life for patients undergoing cardiac surgery. Quality of life affects morbid outcomes, so further characterization of risk factors for poor quality of life offers an opportunity for intervention.

Preoperative statin intake and morbid events after isolated coronary artery bypass grafting.

STUDY OBJECTIVE: To examine the effect of statins on morbidity and mortality in patients after isolated coronary artery bypass grafting (CABG). DESIGN: Observational cohort study. SETTING: Tertiary-care teaching hospital. MEASUREMENTS: Data from 2497 adult patients who underwent isolated CABG between January 2002 and June 2004 were studied. Patient characteristics and intraoperative variables were prospectively collected. End points were major morbid events and in-hospital mortality. A propensity score was estimated for each patient using logistic regression on the probability of statin use. Patients were also classified into 5 quintile groups according to their propensity score. Outcome variables were compared for propensity-matched pairs and quintile groups between those who received and did not receive statin therapy. MAIN RESULTS: Propensity matching resulted in a similar distribution of variables among the 654 matched pairs. Similar perioperative mortality was found between matched pairs with statin therapy vs no statin therapy, 5 (0.76%) and 8 (1.2%), (P = 0.40), respectively. Cardiac, neurologic, renal and respiratory morbidity, occurrence of atrial fibrillation, and length of hospital stay were similar between the matched pairs and among quintiles of propensity scores. CONCLUSIONS: Preoperative statin intake did not reduce the frequency of major perioperative morbid events after isolated CABG.

Effect of functional health-related quality of life on long-term survival after cardiac surgery.

BACKGROUND: Health-related quality-of-life instruments have become important measures of early health outcomes after cardiac surgery. The relationship between quality of life after recovery from surgery and subsequent long-term survival has not previously been explored. Our objective was to determine whether the Duke Activity Status Index (DASI) was predictive of subsequent time-related survival after recovery from cardiac surgery. METHODS AND RESULTS: We examined survival status among 6305 patients who underwent isolated coronary artery bypass grafting with or without valve procedures or isolated valve procedure between May 1995 and June 1998 who had a preoperative baseline and follow-up DASI. The postoperative DASI was administered nominally at 6 and 12 months. Baseline and perioperative variables and postoperative morbid events were prospectively collected concurrently with patient care. The end point was all-cause mortality. The Social Security Death Index was queried for survival status. Cox proportional-hazards analysis was used to study the associations between DASI, a number of traditional risk factors, and survival. Median follow-up was 8.6 years. The "dose-response" relationship between baseline and follow-up DASI and risk of long-term death was established. Follow-up DASI was associated with risk-adjusted long-term survival hazard ratio of 0.98 per unit increase (confidence limits, 0.97 to 0.98; P<0.0001). Achieving maximum baseline DASI was associated with better risk-adjusted long-term survival (hazard ratio, 0.64; confidence limits, 0.50 to 0.83; P=0.0005). CONCLUSIONS: Poor health-related quality of life after recovery from cardiac surgery identifies patients who are at risk for reduced long-term survival.

Increased risk associated with combined carotid endarterectomy and coronary artery bypass graft surgery: a propensity-matched comparison with isolated coronary artery bypass graft surgery.

OBJECTIVE: Risk associated with combined carotid endarterectomy and coronary artery bypass graft surgery (CEA/CABG) is controversial. The present study objective was to compare morbidity and mortality outcomes in well-matched patients who underwent combined CEA/CABG surgery with patients undergoing isolated CABG surgery with and without a history of a prior CEA. DESIGN: This investigation was designed as a retrospective case-controlled study using data from the Cardiothoracic Anesthesia Patient Registry in a single tertiary institution. The patient population consisted of 1,698 isolated CABG surgery patients with carotid artery stenosis >40%, 708 patients who underwent an isolated CABG surgery but had a history of a prior CEA, and 272 combined CEA/CABG surgery patients who underwent surgery from January 4, 1993, through June 30, 2003. Propensity modeling techniques were used to calculate a propensity score for each patient. Greedy matching resulted in 272 propensity-matched pairs of combined CEA/CABG and isolated CABG patients (primary analysis) and 241 propensity-matched pairs of combined CEA/CABG surgery and isolated CABG surgery with previous CEA patients (secondary analysis). A Fisher exact, chi-square, Wilcoxon rank sum, and Student t test were applied appropriately to compare the propensity-matched pairs. RESULTS: The distribution of covariates among the propensity-matched combined CEA/CABG and isolated CABG groups were similar. Among the propensity-matched pairs in the primary analysis, overall morbidity and mortality were higher in the combined CEA/CABG group compared with the CABG group alone (overall morbidity 15% v 8.8%, p = 0.025, and mortality 5.2% v 1.1%, p = 0.007, respectively). Median intensive care unit (ICU) length of stay was longer (47 v 31 hours, p = 0.004) and hospital length of stay was longer (12 v 9 days, p < 0.001) for the combined CEA/CABG surgery compared with isolated CABG surgery, respectively. Postoperative cardiac, neurologic, serious infection, and renal morbid events were similar between the 2 groups. In the secondary analysis, the rates of mortality, overall morbidity, and neurologic morbidity were similar between the groups, whereas the median ICU and hospital length of stay were significantly longer in the combined CEA/CABG group (47.6 v 39.8 hours, p = 0.025, and 12.0 v 9.0 days, p < 0.001, respectively). CONCLUSIONS: Increased mortality and overall morbidity outcomes were found in the combined CEA/CABG group when compared with well-matched isolated CABG patients, but similar when compared with well-matched isolated CABG patients with a history of previous CEA. Patients undergoing combined CEA/CABG procedures had significantly longer ICU and hospital lengths of stay compared with patients undergoing isolated CABG procedures.

The impact of gender on in-hospital mortality and morbidity after isolated aortic valve replacement.

The objective of our retrospective investigation was to examine the influence of gender on in-hospital mortality and morbidity after isolated aortic valve replacement (AVR). Between January 1993 and June 2002, 2212 patients (782 females, 1430 males) underwent AVR. Propensity matching was used to adjust for numerous differences in baseline characteristics and perioperative variables between groups. Unadjusted in-hospital mortality was higher in females (27 [3.5%] females versus 23 [1.6%] males; P = 0.005). An analysis using 1:1 matching by propensity score did not find a significant difference in in-hospital mortality [OR (95% confidence intervals), 1.0 [0.4, 2.6]; P = 0.99) or overall morbidity (1.4 [0.7, 2.5]; P = 0.29) between groups. Further analyses, including classification of women and men into quintile groups by propensity scores and logistic regression models with propensity score adjustment, found that females were at increased risk for cardiac morbidity [OR (95% CI), 3.4 [1.1, 10.8]; P = 0.038), but not mortality (0.9 [0.3, 2.5]; P = 0.88) nor other morbidities. These results suggest that there is no greater than a 2.5-fold increase in risk for females compared with males undergoing AVR. Female gender, however, may impart increased risk for cardiac morbidity after AVR.

Morbidity and mortality risk associated with red blood cell and blood-component transfusion in isolated coronary artery bypass grafting.

OBJECTIVE: Our objective was to quantify incremental risk associated with transfusion of packed red blood cells and other blood components on morbidity after coronary artery bypass grafting. DESIGN: The study design was an observational cohort study. SETTING: This investigation took place at a large tertiary care referral center. PATIENTS: A total of 11,963 patients who underwent isolated coronary artery bypass from January 1, 1995, through July 1, 2002. INTERVENTIONS: None. MEASUREMENTS AND MAIN RESULTS: Among the 11,963 patients who underwent isolated coronary artery bypass grafting, 5,814 (48.6%) were transfused. Risk-adjusted probability of developing in-hospital mortality and morbidity as a function of red blood cell and blood-component transfusion was modeled using logistic regression. Transfusion of red blood cells was associated with a risk-adjusted increased risk for every postoperative morbid event: mortality (odds ratio [OR], 1.77; 95% confidence interval [CI], 1.67-1.87; p<.0001), renal failure (OR, 2.06; 95% CI, 1.87-2.27; p<.0001), prolonged ventilatory support (OR, 1.79; 95% CI, 1.72-1.86; p<.0001), serious infection (OR, 1.76; 95% CI, 1.68-1.84; p<.0001), cardiac complications (OR, 1.55; 95% CI, 1.47-1.63; p<.0001), and neurologic events (OR, 1.37; 95% CI, 1.30-1.44; p<.0001). CONCLUSIONS: Perioperative red blood cell transfusion is the single factor most reliably associated with increased risk of postoperative morbid events after isolated coronary artery bypass grafting. Each unit of red cells transfused is associated with incrementally increased risk for adverse outcome.

Transfusion in coronary artery bypass grafting is associated with reduced long-term survival.

BACKGROUND: Perioperative red blood cell (PRBC) transfusion has been associated with early risk for morbid outcomes, but risk related to long-term survival has not been thoroughly explored. Therefore, we examined the influence of PRBC transfusion and component therapy on long-term survival after isolated coronary artery bypass grafting after controlling for the effect of demographics, comorbidities, operative factors, and the early hazard for death. METHODS: The US Social Security Death Index was used to ascertain survival status for 10,289 patients who underwent isolated coronary artery bypass grafting from January 1, 1995 through June 28, 2002. The outcome measure was all-cause mortality during the follow-up period. Unadjusted survival estimates were performed using the Kaplan-Meier techniques. Survival curves for transfusion status were compared with the log-rank test. The parametric decomposition model was used for risk-adjusted survival. A balancing score was calculated for each patient and forced into the final model. RESULTS: Survival among transfused patients was significantly reduced as compared with nontransfused patients. The instantaneous risk of death displayed a biphasic pattern: a declining hazard phase from the time of the operation (early hazard) up until 6 months postoperatively and then a late hazard that continued out until about 10 years. Transfusion of red cells was associated with a risk-adjusted reduction in survival for both the early (0.34 +/- 0.02, p < 0.0001) and late phases (0.074 +/- 0.016, p < 0.0001). CONCLUSIONS: Perioperative PRBC transfusion is associated with adverse long-term sequela in isolated CABG. Attention should be directed toward blood conservation methods and a more judicious use of PRBC.

"Renal dose" dopamine is associated with the risk of new-onset atrial fibrillation after cardiac surgery.

OBJECTIVE: "Renal dose" dopamine (rDA; 1-3 microg/kg per min) is administered to patients after cardiac surgery to preserve or improve renal function. Many of these patients develop new-onset postoperative atrial fibrillation or atrial flutter (pAF) that could be related to rDA administration. The objective of this investigation was to determine whether there was an association between rDA and new-onset pAF in patients undergoing coronary artery bypass grafting with cardiopulmonary bypass (CABG). SETTING: Research hospital. SUBJECTS: The study population consisted of 1,731 patients undergoing CABG. INTERVENTIONS: CABG with and without rDA. DESIGN: After approval by the institutional review board, a retrospective study using the Cardiothoracic Anesthesia Patient Registry was undertaken to determine the association between rDA and pAF in patients undergoing CABG. Patients with a documented history of atrial fibrillation, those who required inotrope use during or after surgery, and those having valve surgery were excluded. MEASUREMENTS AND MAIN RESULTS: One-thousand seven-hundred thirty-one patients undergoing CABG during the period of January 1, 2000, through June 30, 2002, were the study population; of these, 15.0% (260/1,731) developed pAF. The incidence of pAF was 23.3 % (41/176) among patients who received rDA and 14.1% (219/1,555) among those who did not receive rDA. In the multivariable logistic regression model, patient age, gender, chronic obstructive pulmonary disease or asthma, and rDA were associated with pAF (p < .01). Receipt of rDA increased the odds of developing pAF by 74%, independent of the effect of other variables. CONCLUSIONS: Renal-dose dopamine is associated with a 1.74 odds ratio of pAF developing after CABG.