Duration of red-cell storage and complications after cardiac surgery.

BACKGROUND: Stored red cells undergo progressive structural and functional changes over time. We tested the hypothesis that serious complications and mortality after cardiac surgery are increased when transfused red cells are stored for more than 2 weeks. METHODS: We examined data from patients given red-cell transfusions during coronary-artery bypass grafting, heart-valve surgery, or both between June 30, 1998, and January 30, 2006. A total of 2872 patients received 8802 units of blood that had been stored for 14 days or less ("newer blood"), and 3130 patients received 10,782 units of blood that had been stored for more than 14 days ("older blood"). Multivariable logistic regression with propensity-score methods was used to examine the effect of the duration of storage on outcomes. Survival was estimated by the Kaplan-Meier method and Blackstone's decomposition method. RESULTS: The median duration of storage was 11 days for newer blood and 20 days for older blood. Patients who were given older units had higher rates of in-hospital mortality (2.8% vs. 1.7%, P=0.004), intubation beyond 72 hours (9.7% vs. 5.6%, P<0.001), renal failure (2.7% vs. 1.6%, P=0.003), and sepsis or septicemia (4.0% vs. 2.8%, P=0.01). A composite of complications was more common in patients given older blood (25.9% vs. 22.4%, P=0.001). Similarly, older blood was associated with an increase in the risk-adjusted rate of the composite outcome (P=0.03). At 1 year, mortality was significantly less in patients given newer blood (7.4% vs. 11.0%, P<0.001). CONCLUSIONS: In patients undergoing cardiac surgery, transfusion of red cells that had been stored for more than 2 weeks was associated with a significantly increased risk of postoperative complications as well as reduced short-term and long-term survival.

Predictors of prolonged postoperative endotracheal intubation in patients undergoing thoracotomy for lung resection.

OBJECTIVE: The aim of this study was to identify predictors of delayed endotracheal extubation defined as the need for postoperative ventilatory support after open thoracotomy for lung resection. DESIGN: An observational cohort investigation. SETTING: A tertiary referral center. PARTICIPANTS: The study population consisted of 2,068 patients who had open thoracotomy for pneumonectomy, lobectomy, or segmental lung resection between January 1996 and December 2005. INTERVENTIONS: Not applicable. MEASUREMENTS AND MAIN RESULTS: Preoperative and intraoperative variables were collected concurrently with the patient's care. Risk factors were identified using logistic regression with stepwise variable selection procedure on 1,000 bootstrap resamples, and a bagging algorithm was used to summarize the results. Intraoperative red blood cell transfusion, higher preoperative serum creatinine level, absence of a thoracic epidural catheter, more extensive surgical resection, and lower preoperative FEV(1) were associated with an increased risk of delayed extubation after lung resection. CONCLUSION: Most predictors of delayed postoperative extubation (ie, red blood cell transfusion, higher preoperative serum creatinine, lower preoperative FEV(1), and more extensive lung resection) are difficult to modify in the perioperative period and probably represent greater severity of underlying lung disease and more advanced comorbid conditions. However, thoracic epidural anesthesia and analgesia is a modifiable factor that was associated with reduced odds for postoperative ventilatory support. Thus, the use of epidural analgesia may reduce the need for post-thoracotomy mechanical ventilation.

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.

Health-related quality of life after cardiac surgery.

Health-related quality of life (HRQOL) assessments are designed to reflect a patient's perspective of how a disease has affected their overall health status. Patient-centered outcomes are of value both for risk assessment and as an outcome measure. Strategies for analyzing HRQOL data are inconsistent primarily because the data frequently do not meet underlying assumptions of traditional methods for statistical analyses and require a careful analytic approach.

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.

Impact of prosthesis-patient size on functional recovery after aortic valve replacement.

BACKGROUND: Prosthesis-patient size mismatch results when an implanted prosthetic aortic valve is of insufficient size for a patient's body surface area. The relation between prosthesis-patient size and functional capacity and adverse postoperative outcome is inconsistent. Our objectives were to examine the impact of valve replacement, continuous prosthesis-patient size, and other factors on functional recovery after aortic valve replacement (AVR) with the Duke Activity Status Index (DASI). METHODS AND RESULTS: From June 15, 1995, through May 14, 1998, 1108 patients underwent AVR after completing a DASI survey. Of these, 1014 completed a postoperative DASI survey at an average of 8.3 months postoperatively. Logistic ordinal regression was used to examine the influence of demographic variables, comorbidities, baseline DASI scores, indexed valve orifice area, standardized orifice size, and postoperative morbid events on postoperative DASI. There was overall improvement in postoperative functional recovery reflected by median preoperative and postoperative DASI scores of 29 and 46, P<0.001, respectively. Neither indexed orifice area, P=0.94, nor standardized orifice size, P=0.96, was associated with functional recovery. Female sex, increasing age, elevated serum creatinine, increased central venous pressure, and red blood cell transfusion were factors associated with poor postoperative functional recovery. CONCLUSIONS: A majority of patients report improvement in functional quality of life early after AVR. Similar functional recovery was demonstrated for patients along the full spectrum of valve sizes indexed to body size, even for values considered to represent severe mismatch for patient size. Factors other than prosthesis-patient size influence functional quality of life early after AVR.

Gender and outcomes after coronary artery bypass grafting: a propensity-matched comparison.

OBJECTIVE: Our objective is to determine whether gender is a marker or a causal influence for poor outcomes after coronary revascularization. METHODS: Propensity-modeling techniques were used to investigate whether gender adversely impacts outcomes after coronary revascularization. A parsimonious explanatory model was developed by bootstrap bagging with variable selection from 64 baseline and 37 operative variables. Propensity scores were calculated from a logistic model that included the parsimonious model and additional baseline variables. Greedy matching techniques were applied to match female and male patients to the nearest propensity scores. Comparisons were made among the propensity-matched women and men. RESULTS: Of the 15,597 patients undergoing isolated coronary artery bypass graft surgery, only 26% of the 3596 women were matched on propensity scores with men. Distribution of covariates among the matched pairs was, on average, equal. Postoperative mortality (P =.76), neurologic morbidity (global deficit P =.07, focal deficit P =.51), infection (sepsis P =.88), mediastinitis (P =.18), renal failure (P =.84), intra-aortic balloon pump usage (P =.61), and reoperation for bleeding (P =.10) were similar among women and men. Occurrence of Q-wave myocardial infarction (P = <.01), postoperative inotropic usage (P = <.01), and prolonged ventilatory support (P =.02) were more common in women compared with propensity-matched men. CONCLUSIONS: The preoperative profiles of women and men are markedly different. Propensity matching women and men was difficult, because only 26% of women were able to be matched with men. However, in well-matched patients, female gender was not associated with increased mortality and had minimal impact on morbidity after coronary artery bypass grafting.

Gender profiling in coronary artery bypass grafting.

OBJECTIVE: Although women are reported to be at increased risk of poor outcome after coronary artery bypass grafting, female gender may simply be a marker of a high-risk profile. Therefore, the objective of this study was to characterize the difference between the female and male profiles of patients presenting for coronary artery bypass grafting. METHODS: From January 1993 to June 2002, 15,597 patients underwent isolated coronary artery bypass grafting at a single institution. Multivariable logistic regression was used to develop a model of female gender. RESULTS: Of 15,597 patients, 3596 (23%) were women. Eighteen variables were predictive of the female gender profile, including shorter stature, increased weight, more hypertension, insulin-treated diabetes mellitus, heart failure, and higher triglyceride and high-density lipoprotein cholesterol levels. Hematocrit, bilirubin, and creatinine values were lower in women compared with men. CONCLUSIONS: The preoperative profiles of women and men undergoing coronary artery bypass grafting are dissimilar. Statistical modeling techniques provide a unique perspective on the preoperative profile of the female patient, who is known to be at a higher risk undergoing coronary artery bypass grafting.

Health-related quality of life after coronary artery bypass grafting: a gender analysis using the Duke Activity Status Index.

OBJECTIVE: Our objectives were to document the preoperative and postoperative functional status of patients undergoing coronary artery bypass grafting, to examine factors that influence functional recovery, and to determine whether gender differences exist in the preoperative and postoperative functional status with the Duke Activity Status Index. METHODS: One thousand eight hundred twenty-five patients undergoing isolated coronary artery bypass grafting had baseline and follow-up quality-of-life surveys. Mean follow-up from baseline to postoperative Duke Activity Status Index was 8.0 months for women and men. The influence of 47 variables, in addition to baseline scores on postoperative functional status, was examined with logistic ordinal modeling. An ordinal model for the follow-up score was determined by means of backward selection, with variables retained if they satisfied the criterion of a P value of less than.05. RESULTS: Median baseline Duke Activity Status Index scores (women, 21.5; men, 32.2; P <.001) and first follow-up scores (women, 42.7; men, 58.2; P <.001) were lower in women than in men. Patients who were older and those who had chronic obstructive pulmonary disease, myocardial infarction, stroke, diabetes, vascular disease, postoperative serious infection, and return to the operating room had lower postoperative scores. After adjusting for these factors, women still had lower follow-up scores (odds ratio for men, 2.1 [95% confidence interval, 1.7-2.6]; P <.001). CONCLUSIONS: A number of preoperative factors, operative variables, and postoperative events are associated with functional recovery after coronary revascularization. In addition, female gender is associated with more postoperative functional impairment after adjusting for these perioperative variables.

The effect of postoperative gastrointestinal complications in patients undergoing coronary artery bypass surgery.

BACKGROUND: Gastrointestinal (GI) complications after coronary artery bypass graft surgery (CABG) are uncommon but associated with a disproportionate share of mortality. We thus identified variables associated with GI complications and analyzed their effect on postoperative mortality in patients undergoing isolated CABG. METHODS: Information from patients who underwent isolated CABG at our institution during a 12-year period was obtained from the Anesthesiology Institute patient registry. Patients who experienced one or more postoperative GI complication(s) during their initial intensive care unit stay were identified. Multivariable logistic regression with backward variable selection was used to determine variables associated with GI complications and to evaluate their effect on mortality. RESULTS: Among 16,043 patients who underwent isolated CABG, 213 (1.43%) had one or more GI complication(s). The main patient variables associated with postoperative GI complications included preoperative (odds ratio, 2.43; 95% confidence interval [CI], 1.39 to 4.23; p < 0.001) and intraoperative (odds ratio, 5.07; 95% CI, 3.08 to 8.35; p < 0.001) intraaortic balloon pump insertion, patient age (odds ratio, 1.65; 95% CI, 1.41 to 1.94; p < 0.001), intraoperative fresh-frozen plasma transfusion (odds ratio, 3.38; 95% CI, 2.12 to 5.41; p < 0.001), and cardiogenic shock (odds ratio, 3.04; 95% CI, 1.12 to 8.24). No difference was detected in complication rates between off-pump and on-pump CABG procedures (1.50% versus 1.30%, respectively; p = 0.63). Postoperative GI complication(s) after CABG was associated with a 12.98 times increase in mortality (p < 0.001). CONCLUSIONS: This single-center cohort study indicates that GI complications after isolated CABG remain rare with an incidence 1.43%. However, GI complications portend a significant mortality. The implications of intraoperative administration of fresh-frozen plasma and insertion of an intraaortic balloon pump deserve further investigation as they are associated with GI complications.

Platelet transfusion in cardiac surgery does not confer increased risk for adverse morbid outcomes.

BACKGROUND: Platelet transfusion has been reported to confer increased morbidity after cardiac surgery but prior studies were limited by confounding variables including red blood cell (RBC) transfusions. Our objective was to examine the impact of platelet transfusion on outcomes in cardiac surgery controlling perioperative risk factors. METHODS: A total of 32,298 patients underwent on-pump isolated coronary artery bypass grafting (CABG), an isolated valve, or a combined CABG and valve procedure between January 1, 1993 and January 1, 2006. Regression analysis and propensity methodology was employed to assess the association between platelet transfusion and morbidity. RESULTS: Univariate comparisons demonstrated that patients who received platelet transfusions had increased morbidity. After risk adjustment with both multivariable regression and propensity methods, platelet transfusion was not significantly associated with in-hospital mortality: odds ratio (OR) 0.74 confidence limits 0.58, 0.95, p = 0.017 and 2.05% vs 3.06%, p = 0.017, respectively. Among 2,774 propensity matched-pairs, platelet transfusion was associated with similar or reduced morbidity, platelets versus no platelets: cardiac 2.42% vs 1.77%, p = 0.09; pulmonary 8.94% vs 9.88%, p = 0.23; renal 1.33% vs 1.48%, p = 0.65; neurologic 2.27% vs 3.21%, p = 0.033; serious infection 4.15% vs 5.34%, p = 0.037; and composite outcome 15.0% vs 17.2%, p = 0.024. Among a propensity-matched subgroup of patients never administered a concomitant RBC transfusion, platelet transfusion was not associated with increased morbidity: 4.49% vs 2.99%, p = 0.31. CONCLUSIONS: Platelet transfusion was not found to increase morbid risk after cardiac surgery. Our results should not be interpreted as advocating platelet transfusions in cardiac surgery; rather, platelet transfusion empirically in the setting of persistent microvascular bleeding is not associated with increased morbid risk.

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.

Persistent effect of red cell transfusion on health-related quality of life after cardiac surgery.

BACKGROUND: Although red blood cell transfusion has been associated with an increase in early morbid outcomes and reduced long-term survival after cardiac surgery, its relationship to functional quality of life after surgery has not been previously explored. Our objective was to investigate the relationship between perioperative red blood cell and component transfusion and functional health-related quality of life 6 to 12 months after cardiac surgery. METHODS: Of 12,536 patients undergoing cardiac surgical procedures between May 1995 and January 1999, 7,321 completed a self-administered Duke Activity Status Index (DASI) survey preoperatively and least one follow-up survey at nominally 6 or 12 months postoperatively. The influence of baseline DASI, preoperative risk factors, clinical status, laboratory values, operative events, and postoperative morbidities on follow-up DASI were examined with ordinal regression modeling. RESULTS: After adjustment for preoperative DASI, demographic, cardiac and noncardiac comorbidity, type of surgery, postoperative complications, and interval between follow-up DASI, during which patients continued to improve (p < 0.0001), postoperative functional status after cardiac surgery was incrementally worse the more perioperative red cells (p < 0.0001) and platelets (p = 0.02) that had been transfused. CONCLUSIONS: Red blood cell and platelet transfusion have an unintended persistently negative risk-adjusted effect on health-related quality of life after cardiac surgery that extends well beyond initial hospitalization. Reductions in functional recovery paralleled increasing units of red blood cells transfused.

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.

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.

Red cell transfusion is associated with an increased risk for postoperative atrial fibrillation.

BACKGROUND: Atrial fibrillation (AF) is a common complication after cardiac surgery and is associated with increased resource utilization. Recent evidence supports a role of inflammation in the development of AF. It is also known that red blood cell transfusion modulates inflammation by increasing plasma levels of inflammatory markers. Therefore, we tested the hypothesis that red blood cell transfusion increases the risk of postoperative AF for patients undergoing cardiac surgery. METHODS: Between February 2002 and January 2005, 5,841 patients underwent isolated coronary artery bypass grafting with or without valve replacement. Patient and procedural variables associated with development of new-onset AF were identified by logistic regression. Propensity score matching was used to confirm results. RESULTS: In addition to older age, prior history of AF, higher preoperative hematocrit, beta-blocker withdrawal, longer aortic clamp time, valve surgery, and intensive care unit inotropic usage, intensive care unit red blood cell transfusion increased risk for AF (odds ratio per unit transfused, 1.18; 95% confidence limits, 1.14, 1.23; p < 0.0001). For the 1,360 propensity-matched pairs, intensive care unit red blood cell transfusion was associated with a significant increase in new-onset AF (620 [46%] versus 522 [38%]; p < 0.001). CONCLUSIONS: Intensive care unit red blood cell transfusion is associated with increased occurrence of postoperative AF after cardiac surgery. This factor should be considered in identifying patients who might benefit from prophylaxis to prevent this common postoperative complication.