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We present an additional advantage of the Risk-Adjusted CUSUM (RA-CUSUM), namely, that its slope can be quantified and is in fact equivalent to Observed (O) minus Expected (E) mortality. That is, the height of the RA-CUSUM is the O minus E deaths, which measures performance since the start of the series, and the slope of the RA-CUSUM is the O minus E mortality which measures performance during a chosen interval. We present a useful graphical tool (Slope-Meter) to allow approximation of this mortality difference by the viewer., (Copyright © 2022 The Society of Thoracic Surgeons. Published by Elsevier Inc. All rights reserved.)

The Society of Thoracic Surgeons (STS) Adult Cardiac Surgery Database is the world's premier adult cardiac surgery outcomes registry. This tutorial explains the following: how STS updates the risk models that are used to calculate the predicted risks of adverse events in the registry; why STS on a quarterly basis adjusts or "calibrates" the observed-to-expected ratios to equal 1 (O/E = 1), thereby effectively making the annual number of adverse events predicted by the model match the annual number of adverse events observed in the entire registry; the differences between the calibrated and uncalibrated O/E ratios; and how and when to use each., (Copyright © 2022 The Society of Thoracic Surgeons. Published by Elsevier Inc. All rights reserved.)

Reporting of risk-adjusted surgical outcomes is commonly used to compare providers and track changes over time. Preferred graphical methods use the relationship of the observed to the expected values of outcome events, including their ratio (O/E), and the cumulative sum (CUSUM) of their differences over time, called Risk-Adjusted CUSUM (RA-CUSUM) or Variable Life Adjusted Display (VLAD). We demonstrate these methods using operative mortality data for 7255 isolated coronary artery bypass graft patients from January 2014 to June 2017. RA-CUSUM and VLAD are excellent techniques to display risk-adjusted outcomes and, unlike O/E, can provide continuous monitoring as performance varies over time., (Copyright © 2021 The Society of Thoracic Surgeons. Published by Elsevier Inc. All rights reserved.)

To compare structural valve deterioration (SVD) among bioprosthetic aortic valve types, a PubMed search found 54 papers containing SVD-free curves extending to at least 10 years. The curves were digitized and fit to Weibull distributions, and the mean times to valve failure (MTTF) were calculated. Twelve valve models were collapsed into four valve types: Medtronic (Medtronic, Minneapolis, MN) and Edwards (Edwards Lifesciences, Irvine, CA) porcine; and Sorin (Sorin Group [now LivaNova], London, United Kingdom) and Edwards pericardial. Meta-regression found MTTF was associated with the patient's age, publication year, SVD definition, and valve type. Sorin pericardial valves had significantly lower risk-adjusted MTTF (higher SVD risk), and there were no significant differences in MTTF among the other three valve types., (Copyright © 2017 The Society of Thoracic Surgeons. Published by Elsevier Inc. All rights reserved.)

Outcomes of cardiothoracic surgery are usually compared among hospitals or physicians by reporting the frequency of in-hospital mortality. Although there is agreement that these frequencies should be adjusted for case mix, there remains uncertainty about the value of using a statistical model that represents hospitals as random effects as opposed to the conventional approach of fixed effects. For years, the Northern New England Cardiovascular Disease Study Group has compared in-hospital mortality after coronary artery bypass graft surgery among centers using a fixed effects approach. An alternative method using random effects has become increasingly popular, and is the method used by cardiothoracic surgery registries such as the Massachusetts Data Analysis Center. The purpose of this report is to provide a short background on fixed versus random effects modeling, describe the use of shrinkage estimators including empirical Bayes, and illustrate them using data from the Northern New England Cardiovascular Disease Study Group. We conclude that both are acceptable approaches to hospital profiling if done in combination with appropriate risk adjustment., (Copyright © 2015 The Society of Thoracic Surgeons. Published by Elsevier Inc. All rights reserved.)

This article summarizes the long-term clinical results of the Food and Drug Administration-approved heart valves, provides current updates to the objective performance criteria (OPC) used to evaluate new heart valve prostheses, and documents the steps that the International Organization for Standardization Committee used to arrive at the updated OPC. Data were extracted from 19 Food and Drug Administration summaries of safety and effectiveness data reports (31 series) and 56 literature articles (85 series) published from 1999 to 2012. The OPC were calculated for five valve-related complications by valve type (mechanical and bioprosthetic) and valve position (aortic and mitral)., (Copyright © 2014 The Society of Thoracic Surgeons. Published by Elsevier Inc. All rights reserved.)

Background: New York (NY) valve and valve/coronary artery bypass grafting (CABG) mortality risk models, developed from operations performed in 2007 to 2009, have just been published. These models were validated using NY data from 2004 to 2006. The authors stated that their models "should also be validated by testing them against non-New York populations." Thus, we validated the NY models with the Providence Health & Services-Swedish Health Services (PH&S-SHS) cardiac surgical data and also compared them with The Society of Thoracic Surgeons (STS) mortality risk models., Methods: The PH&S-SHS validation data set contained 4,021 isolated valve and 2,406 valve/CABG operations, performed from 2008 to 2012. The risk models (NY logistic and score models and the STS models) were recalibrated to equalize the expected and observed number of deaths. Discrimination was tested by C statistics and calibration by Hosmer-Lemeshow statistics., Results: PH&S-SHS operative mortality rates were 2.6% and 5.5% in the valve and valve/CABG operations, respectively, and were lower than the NY rates. The C statistics for the NY logistic valve and valve/CABG models were 0.777 and 0.727, respectively, and were very similar for the NY score models. Calibration was good for the NY valve model (p=0.85), but not for the NY valve/CABG model (p=0.01). The STS models had better discrimination than NY models and good calibration., Conclusions: The NY logistic and score models for valve operations fit the PH&S-SHS data well with acceptable discrimination and good calibration. The NY models for valve/CABG operations fit the PH&S-SHS data with acceptable discrimination and poor calibration. STS logistic regression models fit the PH&S-SHS data somewhat better., (Copyright © 2013 The Society of Thoracic Surgeons. Published by Elsevier Inc. All rights reserved.)

Background: In our effort to reduce the use of blood products in cardiac operations in a health care system, we noted variations in transfusion practices among facilities. Interestingly, surgeons practicing at the same hospital had similar transfusion rates. We sought to quantitate the contribution of hospital influence on individual surgeons' transfusion practices., Methods: Blood transfusion data for coronary artery bypass graft operations at 12 Providence Health & Services facilities between January 2008 and June 2011 were reviewed. Frequency of perioperative blood transfusion, amount of transfusion, components transfused, and timing of transfusions were compared. Variation among surgeons at the same institution vs between institutions was computed based on multilevel mixed-effect logistic and linear regression models. Intraclass correlation coefficients were calculated., Results: A total of 5,744 nonemergency first-time coronary artery bypass graft procedures were performed by 42 not-low volume (n>30 in 2.5 years) surgeons at 12 Providence Health & Services hospitals during the 3.5-year study period. Frequency, amount, timing, and blood component usage were different among facilities but relatively similar for surgeons within a facility. The variance of red blood cell transfusion rate among hospitals (.82) is more than two times that among surgeons practicing within the same hospital (.35). Thus, surgeons contribute 30% to the variation, and 70% of the total variation can be explained by the hospital effect., Conclusions: In our multihospital system, the hospital that a surgeon practices at plays a larger role in determining blood utilization than the individual surgeon's preference., (Copyright © 2013 The Society of Thoracic Surgeons. Published by Elsevier Inc. All rights reserved.)

Survival is an end point of immense interest in cardiothoracic research. In observational studies, the comparison of survival between groups of patients is usually accomplished using a toolbox that includes Kaplan-Meier survival curves and the Cox model. The Cox model yields comparisons between groups adjusted for case-mix differences, whereas the Kaplan-Meier is a plot of survival over time without adjustment. During the past decade, new methods have emerged for case-mix adjustment of survival curves and are increasingly being used in cardiothoracic research. The purpose of this report is to describe, illustrate, and review several approaches to case-mix adjusted survival (or event-free) curves., (Copyright © 2012 The Society of Thoracic Surgeons. Published by Elsevier Inc. All rights reserved.)

Background: No information exists evaluating the costs of complications or death after lobectomy or pneumonectomy., Methods: We analyzed hospital costs for 294 patients who underwent lobectomy (n=268) or pneumonectomy (n=26) from January 2005 through September 2007. The patients were categorized into two groups on the basis of clinical outcomes: uncomplicated versus complications or death. A cost prediction model was constructed with linear regression using uncomplicated patients only. The model was applied to the complications or death group to predict the expected cost as if they had no complication. The risk-adjusted cost of complications or death was quantified by the difference between the observed cost and the expected cost., Results: There were 241 patients in the uncomplicated group (19 pneumonectomy), and 53 patients had complications or death (7 pneumonectomy). Length of stay was shorter for uncomplicated versus complications or death for both lobectomy and pneumonectomy. Pneumonectomy was costlier than lobectomy. Experiencing complications or death was costlier than costs associated with uncomplicated cases. The actual cost for uncomplicated cases was $18,380. The expected cost for complications or death was similar to that for uncomplicated cases regardless of the number of complications or death. The mean risk-adjusted cost of complications (95% confidence interval) increased by the number of complications: $11,693 ($4,430 to $18,957), $26,673 ($12,320 to $41,025) and $128,450 ($93,971 to $162,930) for 1, 2, and 3 complications, respectively. It was $49,823 ($23,187 to $76,459) for death., Conclusions: Patients experiencing complications or death have a similar perioperative risk profile as patients without complications. Hospital death or postoperative complications after lobectomy or pneumonectomy are economically costly. Decreasing inpatient death or complications would result in substantial cost-of-care savings., (Copyright © 2011 The Society of Thoracic Surgeons. Published by Elsevier Inc. All rights reserved.)

The Society of Thoracic Surgeons National Adult Cardiac Surgery Database (STS NCD) has become the national benchmark for cardiac surgery reporting. Several important aspects of its risk-adjustment reporting are discussed, with special emphasis on using the reported individual STS risk scores for analysis and evaluation: (1) Different risk models are used in different STS NCD versions. (2) STS calibrates risk scores annually to make the annual predicted rates equal the observed rates. (3) The risk scores given by the STS, whether in the approved STS data collection software programs, published risk models, or online calculator, are not calibrated. (4) The end-user is required to calibrate the STS risk scores before using them. (5) After calibration, the STS predicted risk for any given patient is usually smaller, sometimes less than half of the uncalibrated value. (6) STS uses an observed/expected ratio method to calibrate the risk scores; for technical reasons, it is preferable to use an odds ratio method., (2010 The Society of Thoracic Surgeons. Published by Elsevier Inc. All rights reserved.)

Background: Coronary artery shunting during off-pump coronary artery bypass OPCAB procedures has been addressed only infrequently. To assess the protective effect of shunting, we examined CABG patients' postoperative cardiac enzyme levels and preoperative and postoperative ejection fractions., Methods: During OPCAB, we selectively shunted the left anterior descending coronary artery (LAD) to provide myocardial protection when ischemia developed. We prospectively gathered data from 408 consecutive patients who underwent OPCAB. Data on shunt status were available for 386 of these patients. A "flow-through" shunt providing perfusion to the distal LAD was used whenever ST-segment elevations greater than 2 mm occurred or when patients had hemodynamic compromise unexplained by cardiac manipulation. Ejection fraction was assessed 1 to 3 days preoperatively and again 3 to 10 days postoperatively. Creatine kinase (muscle/brain) levels were assessed postoperatively for 24 hours., Results: During OPCAB, 99 patients required shunting for presumed ischemia. Thirty-day cardiac mortality was 1.4% (4 of 296 without a shunt; 0 of 90 with a shunt). In patients without a LAD shunt, the mean peak creatine kinase index was 5.3; in patients who needed a shunt, the index was 5.2. Mean ejection fraction improved from 0.536 to 0.589 in the shunted patients and from 0.53.5 to 0.586 in the nonshunted patients., Conclusions: Selective shunting of the LAD during OPCAB provides effective protection against myocardial ischemia when ischemia is detected by electrocardiogram or when hypotension develops that is unexplained by cardiac manipulation., (2010 The Society of Thoracic Surgeons. Published by Elsevier Inc. All rights reserved.)

Successful publication of a research study usually requires a small p value, typically p < 0.05. Many clinicians believe that a p value represents the probability that the null hypothesis is true, so that a small p value means the null hypothesis must be false. In fact, the p value provides very weak evidence against the null hypothesis, and the probability that the null hypothesis is true is usually much greater than the p value would suggest. Moreover, even considering "the probability that the null hypothesis is true" is not possible with the usual statistical setup and requires a different (Bayesian) statistical approach. We describe the Bayesian approach using a well-established diagnostic testing analogy. Then, as a practical example, we compare the p-value result of a study of aprotinin-associated operative mortality with the more illuminative interpretation of the same study data using a Bayesian approach.

Background: Mounting evidence exists for more restrictive blood transfusion practices in patients undergoing cardiac surgery. Few studies, however, have recognized or agree upon a method by which this decrease in allogeneic red blood cell transfusion can be achieved. We will review our methods and experience in a blood conservation initiative from 2003 to 2007., Methods: A data driven, multidisciplinary effort to decrease allogeneic red blood cell transfusion was instituted in a community hospital. Numerous innovations in treatment protocols were implemented and evaluated. Clinical data from 2003 to 2007 will be presented. Yearly review of outcomes led to an evolving clinical practice and lowered transfusion rates., Results: A total of 2,531 consecutive cardiac surgical procedures were performed during a five-year period. Using a multidisciplinary approach to quality improvement, and with the goal of using fewer blood products, our incidence of allogeneic red blood cell transfusion was decreased, from 43% in 2003 to 18% in 2007. Patient outcomes were not significantly changed., Conclusions: Cardiac surgery in a community hospital can be performed safely with low utilization of allogeneic red blood cell transfusions. A multidisciplinary approach to blood conservation can result in lower transfusion rates and equivalent patient outcomes.

Glomerular filtration rate (GFR) is an important clinical indicator of kidney function. It can be used as an independent predictor of long-term survival after cardiac surgery. Definition, methods of measurement, and corrected value by body surface area are briefly introduced in this paper. Details of the calculation of estimated GFR (eGFR) by Levey's formula with serum creatinine, age, gender, and race are offered. The relationship between estimated GFR and the four factors is shown graphically and discussed. An eGFR/creatinine conversion table for individual patients derived from the eGFR equation with clinically significant cutpoints is given, which can be used by physicians as a pragmatic reference.

Completeness of follow-up is often used as a measure of the quality of follow-up, but the method used to compute it is often not declared. An ideal measure should be based on follow-up years instead of patients. Clark, Altman, and De Stavola proposed such a measure, called "C", which is the percentage of the maximum possible follow-up years, as of a given date, that has actually been accounted for or observed. However, such a measure will underestimate the true completeness, because the denominator (maximum possible follow-up years) does not account for unobserved patient deaths occurring before that date, and therefore, it is realistically unachievable. We propose a modification, C*, of Clark's C, which accounts for the effect of unobserved patient deaths in attenuating the maximum potential follow-up, and thus gives a higher percentage for achieved follow-up completeness. We validated this theoretical improvement by comparing the values of C and C* computed for our long-term coronary artery bypass graft patients to the true completeness, which was obtained by using the National Death Index to complete our missing follow-up data. Using Clark's C, the follow-up completeness was 80.4% and using our C* it is 84.5%, whereas the true follow-up completeness based on National Death Index information was 85.0%.

Background: In survival analysis, a patient who is missing complete follow-up is included in the analysis as a censored observation. The analysis makes the assumption that the censoring is noninformative; that is, that a censored patient has the same risk of death as those who have complete follow-up. We tested this assumption in a large, long-term follow-up study., Methods: From 1986 through 2003, 14,495 patients underwent isolated coronary artery bypass grafting procedures. Of 13,963 eligible patients, 2312 were lost to follow-up. We obtained National Death Index data to complete our follow-up, and then compared survival between the original data and the complete National Death Index-augmented data., Results: The National Death Index data revealed 855 additional deaths and increased the total follow-up years from 86,810 to 102,157. Survival estimates and regression models did not differ between the original and National Death Index-augmented data., Conclusions: Patients lost to follow-up might not differ with regard to survival from those with complete data. The requirement for 95% completeness is somewhat arbitrary. The quality and type of follow-up is more important than the percentage in time-related analyses.

The probability of a type of failure that is not inevitable, but can be precluded by other events such as death, is given by the cumulative incidence function. In cardiac research articles, it has become known as the actual probability, in contrast to the actuarial methods of estimation, usually implemented by the Kaplan-Meier (KM) estimate. Unlike cumulative incidence, KM attempts to predict what the latent failure probability would be if death were eliminated. To do this, the KM method assumes that the risk of dying and the risk of failure are independent. But this assumption is not true for many cardiac applications in which the risks of failure and death are negatively correlated (ie, patients with a higher risk of dying have a lower risk of failure, and patients with a lower risk of death have a higher risk of failure, which is a condition called informative censoring). Recent editorials in two cardiac journals have promoted the use of the KM method (actuarial estimate) for competing risk events (specifically for heart valve performance) and criticized the use of the cumulative incidence (actual) estimates. This report has two aims: to explain the difference between these two estimates and to show why the KM is generally not appropriate. In the process we will rely on alternative representations of the KM estimator (using redistribution to the right and inverse probability weighting) to explain the difference between the two estimates and to show how it may be possible to adjust KM to overcome the informative censoring.

The current Food and Drug Administration (FDA) heart valve guidance document uses an objective performance criteria (OPC) methodology to evaluate the clinical performance of prosthetic heart valves. OPC are essentially historical controls, but they have turned out to be an adequate, and perhaps optimal, study design in this situation. Heart valves have a simple open-and-close mechanism, device effectiveness is easy to document, and the common complications (thromboembolism, thrombosis, bleeding, leak, and infection) are well known and easily detected. Thus, randomized clinical trials (RCTs) have not been deemed necessary for the regulatory approval of prosthetic heart valves. The OPC are derived from the average complication rates of all approved heart valves. Studies based on OPC have been shown to work well; many different valve models have gained FDA market approval based on this methodology. Although heart valve RCTs are not required by the FDA, they have been done to compare valves or treatment regimens after approval. Recently, the Artificial Valve Endocarditis Reduction Trial (AVERT) was designed to compare a new Silzone sewing ring, designed to reduce infection, with the Standard sewing ring on a St. Jude Medical heart valve. This was the largest heart valve RCT ever proposed (4,400 valve patients, followed for as long as 4 years), but it was stopped prematurely because of a high leak rate associated with the Silzone valve. Examining the results showed that a much smaller, OPC-based study with 800 patient-years would have been sufficient to disclose this complication of the Silzone valve.

Background: Although coronary artery bypass graft surgery (CABG) has long been the "gold standard" for treatment of multivessel coronary artery disease, current percutaneous interventional technologies are challenging that claim. We sought to determine long-term survival after isolated CABG to establish a baseline for comparison with interventional patients., Methods: From 1968 through 2003, 20,835 patients underwent 22,378 isolated CABG procedures by a single surgical team. The intermittent fibrillation technique without use of cardioplegia was consistently utilized as a method of myocardial protection, using cardiopulmonary bypass. Patients were prospectively followed with direct contact at annual intervals. Age stratified survival was analyzed. Long-term survival was compared between pre-stent era patients and post-stent era patients., Results: Operative mortality was 2.5% (95% confidence interval: 2.2% to 2.7%) and remained approximately constant since 1974 despite increasing patient age and comorbidities. Follow-up was 84% complete with 172,773 patient-years. Overall 5-, 15-, 25-, and 35-year survival was 86% +/- 0.3%, 48% +/- 0.5%, 19% +/- 0.6%, and 7% +/- 1.2%. By Cox regression, older age, prior myocardial infarction, hypertension, diabetes mellitus, and history of CABG were risk factors for long-term survival. Surgery performed during the post-stent era was a protective factor for long-term survival., Conclusions: This study presents the long-term survival of a large series of patients after CABG performed by a single surgical team with intermittent fibrillation technique. There was no difference in observed survival up to 8 years between the pre-stent and post-stent eras. This study establishes a baseline of long-term CABG survival that could be used for comparison with other methods of surgical, or nonsurgical coronary revascularization.

Background: One determinant of durability of the homograft in the aortic position is the implantation technique. This study uses meta-analytical techniques to evaluate the differences in early and long-term outcomes of patients undergoing aortic homograft implantation with either a root replacement or a root preserving technique., Methods: A systematic review of the literature (1965-2005) reporting results after homograft implantation in the aortic position with emphasis in the implantation technique was performed. Random and fixed-effects models were used. Cumulative and influential meta-analysis, graphic exploration, and sensitivity analysis were carried out to explain the heterogeneity between studies and to investigate potential publication bias., Results: Eleven studies were included. None of the studies was randomized. There was no significant difference in early mortality between root replacement and root preserving groups (odds ratio = 2.57 with 95% confidence interval [CI] 0.68-9.72 in random-effects model) and the root replacement group had a significantly lower rate of reoperation during long-term follow-up (hazard ratio = 0.55 with 95% CI 0.38-0.80 in random-effects model). Subgroup analysis focusing on patients having the subcoronary technique for homograft implantation showed similar results. Significant heterogeneity between studies can be detected. No publication bias was found., Conclusions: There was no significant difference in early mortality between root replacement and root preserving groups. However, the root replacement technique group had a significantly lower rate of reoperation during long-term follow-up. Excluding outliers identified in a funnel plot reduced the heterogeneity and reached a similar conclusion.

Background: The second-generation Carpentier-Edwards pericardial valve (Edwards Lifesciences LLC, Irvine, CA) is widely used for aortic valve replacement. However, knowledge on the long-term outcomes of patients after valve implantation is incomplete. We used microsimulation to calculate the long-term outcome of any given patient after aortic valve replacement with the Carpentier-Edwards pericardial valve., Methods: A meta-analysis of 8 reports on aortic valve replacement with the Carpentier-Edwards pericardial valve (2,685 patients; 12,250 patient years) was used to estimate the hazards of valve-related events other than structural valvular deterioration. Structural valvular deterioration was described by age-dependent Weibull curves calculated from 18-year follow-up, premarket approval, Carpentier-Edwards pericardial primary data. These estimates provided the input data for the parameters of the microsimulation model, which was then used to calculate the outcomes of patients of different ages after valve implantation. The model estimates of survival were validated using two external data sets., Results: The Weibull analysis estimated a median time to reoperation for structural valvular deterioration ranging from 18.1 years for a 55-year-old male to 23.2 years for a 75-year-old male. For a 65-year-old male, microsimulation calculated a life expectancy and event-free life expectancy of 10.8 and 9.1 years, respectively. The lifetime risk of at least one valve-related event was 38% and that of reoperation due to structural valvular deterioration 17%, respectively, for this patient. The model estimates of survival showed good agreement with external data., Conclusions: Microsimulation provides detailed insight into the long-term prognosis of patients after aortic valve replacement. The Carpentier-Edwards pericardial valve performs satisfactorily and offers a low lifetime risk of reoperation due to structural valvular deterioration, especially for elderly patients requiring aortic valve replacement.

Background: The Northern New England Cardiovascular Disease Study Group (NNE) recently published risk models for hospital mortality after heart valve surgery. The Providence Health System Cardiovascular Study Group (PHS) has been collecting similar heart valve data for 8 years, providing an ideal opportunity to both validate the NNE risk models and attempt to produce an improved model, by using some different modeling techniques., Methods: From 1997 to 2004, 3,324 patients aged 30 to 95 years underwent aortic valve replacement (AVR), and 1,596 underwent mitral valve replacement or repair (MVRR) at one of nine PHS medical centers. We used area under the receiver operating characteristic curve (c-index) to measure model discrimination, and Hosmer-Lemeshow statistic (H-L) to measure calibration. We modified the NNE models by ungrouping continuous variables, seeking optimal transformations of continuous variables, and imputing missing values by multiple regression., Results: The prevalence and the lethality of risk factors were similar in PHS and NNE patients. The NNE models fit PHS patients well: c-index (95% confidence interval) = 0.75 (0.70 to 0.80) for AVR and 0.81 (0.76 to 0.86) for MVRR; H-L = 3.95 (p = 0.861) for AVR and 7.10 (p = 0.526) for MVRR. A single PHS model performed slightly better for both positions: c-index = 0.79 (0.75 to 0.83) for AVR and 0.84 (0.80 to 0.88) for MVRR; H-L = 2.75 (p = 0.949) for AVR and 12.21 (p = 0.142) for MVRR., Conclusions: The NNE models for aortic and mitral valve surgery were successfully validated using PHS patients. Using some different statistical approaches to modeling, we produced a new, unified model for both positions.

Background: Off-pump coronary artery bypass (OPCAB) may be associated with improved outcomes when compared with on-pump coronary artery bypass. This study evaluates the use of a system for access and stabilization (SAS) with a coronary stabilizer as well as a clinical effectiveness quality initiative (CEQI) process regarding outcomes. This included the development of an expanded heart care team as well as standardization and refinement of perioperative care at The Lankenau Hospital (TLH). Our aim was to evaluate morbidity and mortality of on-pump coronary artery bypass grafting (CABG) compared with OPCAB surgery using SAS in addition to a CEQI initiative., Methods: A retrospective consecutive cohort study using the Society of Thoracic Surgery (STS) National Database was conducted. Three cohorts were analyzed: pre-SAS (December 1, 1999-August 31, 2000); use of SAS only (September 1, 2000-April 30, 2001), and the use of SAS + CEQI process (May 1, 2001-September 30, 2002). Morbidity and mortality for all on-pump CABG procedures performed over the time period of December 1, 1999-September 30, 2002 were compared with the SAS and SAS + CEQI groups only., Results: One-thousand two-hundred sixty-seven procedures were performed; 405 on-pump CABGs, 90 OPCABs pre-SAS, and 772 OPCABs with SAS, of which 552 were in the SAS + CEQI group. Statistically mortality was significantly lower in the SAS + CEQI vs the on-pump group (0.7% vs 3.0%, p < 0.01). The percentage of patients with prolonged ventilation was significantly lower statistically in the SAS + CEQI vs the on-pump group (4.2% vs 9.7%, p < 0.01). Statistically the length of stay was significantly lower in both SAS groups compared with the on-pump group (p < 0.01)., Conclusions: OPCAB surgery using SAS in conjunction with a CEQI initiative improves outcomes for patients compared with on-pump CABG surgery.

Background: Postcardiotomy sternal wound complications remain challenging. The prevailing approach for deep sternal wound infection of debridement and flap coverage without osseous closure makes subsequent reoperation difficult., Methods: An analysis of all patients undergoing cardiac surgery at a single institution between 1986 and 2001 was conducted. Prospective data collection and chart review were used to compare different treatment strategies for sternal complications., Results: Of 5337 patients, 122 had sternal wound complications (2.2%) comprising 15 (0.3%) uninfected dehiscences (El Oakley class 1), 45 (0.8%) superficial infections (El Oakley class 2A), and 62 (1.1%) deep sternal wound infections (El Oakley class 2B). Thirty-two patients with deep sternal infection were treated by debridement, rewiring, and delayed primary closure. There were initial treatment failures in 6 patients (18.8%) and ultimate failures in 2 patients (6.3%), both of whom died. One of these patients had previously received external beam radiation after a radical mastectomy for breast cancer. Median length of stay was 32 days and median time to wound healing was 85 days. Twenty-five patients were managed by muscle flap coverage without sternal reclosure. There were 6 initial treatment failures (24%) but no ultimate failures or deaths (p = NS). Median length of stay was 31 days and median infection time was 161 days., Conclusions: In patients with postcardiotomy deep sternal wound infection without previous chest radiation, debridement, rewiring, and delayed skin closure is effective. It offers a shorter healing time and probably makes late cardiac reoperation safer. We propose an algorithm for the management of poststernotomy complications.

Differences in medical outcomes may result from disease severity, treatment effectiveness, or chance. Because most outcome studies are observational rather than randomized, risk adjustment is necessary to account for case mix. This has usually been accomplished through the use of standard logistic regression models, although Bayesian models, hierarchical linear models, and machine-learning techniques such as neural networks have also been used. Many factors are essential to insuring the accuracy and usefulness of such models, including selection of an appropriate clinical database, inclusion of critical core variables, precise definitions for predictor variables and endpoints, proper model development, validation, and audit. Risk models may be used to assess the impact of specific predictors on outcome, to aid in patient counseling and treatment selection, to profile provider quality, and to serve as the basis of continuous quality improvement activities.

Full Bayesian analysis is an alternative statistical paradigm, as opposed to traditionally used methods, usually called frequentist statistics. Bayesian analysis is controversial because it requires assuming a prior distribution, which can be arbitrarily chosen; thus there is a subjective element, which is considered to be a major weakness. However, this could also be considered a strength since it provides a formal way of incorporating prior knowledge. Since it is flexible and permits repeated looks at evolving data, Bayesian analysis is particularly well suited to the evaluation of new medical technology. Bayesian analysis can refer to a range of things: from a simple, noncontroversial formula for inverting probabilities to an alternative approach to the philosophy of science. Its advantages include: (1) providing direct probability statements--which are what most people wrongly assume they are getting from conventional statistics; (2) formally incorporating previous information in statistical inference of a data set, a natural approach which we follow in everyday reasoning; and (3) flexible, adaptive research designs allowing multiple looks at accumulating study data. Its primary disadvantage is the element of subjectivity which some think is not scientific. We discuss and compare frequentist and Bayesian approaches and provide three examples of Bayesian analysis: (1) EKG interpretation, (2) a coin-tossing experiment, and (3) assessing the thromboembolic risk of a new mechanical heart valve.

Background: The Artificial Valve Endocarditis Reduction Trial (AVERT) was designed to compare endocarditis rates in Silzone versus conventional valves. Recruitment ended January 21, 2000, because of higher rates of paravalvular leakage in patients receiving the Silzone prosthesis. The present analysis determined late event rates that might be used in the management of approximately 36,000 patients who have received the Silzone prosthesis., Methods: A total of 807 patients in 19 centers in North America and Europe were randomized. Mean age was 61+/-11 years; 41% were women. Operations included aortic valve replacement in 59%, mitral valve replacement in 32%, and aortic and mitral valve replacements in 9%; 41% had concomitant operations (26% coronary artery bypass grafting)., Results: Major paravalvular leakage (followed by repair, explant, or mortality) occurred in 18 of 403 patients receiving Silzone valves and 4 of 404 patients without Silzone valves (2-year event-free rates: 91.1% versus 98.9% conventional, p < 0.003). Similarly, 2-year freedom from any explant was lower in the Silzone arm (19 versus 2 events; 90.1% versus 99.4%, p = 0.0002). Rates of mortality and stroke were similar during follow-up., Conclusions: Continued follow-up of AVERT supports the conclusion that the Silzone prosthesis has increased risk of paravalvular leakage requiring reoperation. Overall survival is similar in the two groups.