Prescription-filling rates for key medications in Veterans Affairs patients after coronary artery bypass grafting

PURPOSE

The six-month prescription-filling rates for key secondary-prevention drugs in Department of Veterans Affairs (VA) patients who had undergone coronary artery bypass grafting (CABG) were studied.

METHODS

Patient records for elective CABG from April 2000 through March 2002 (divided into four six-month periods) were analyzed. The study population included 8925 CABG-only patients surviving to hospital discharge. For each six-month period and in aggregate, the primary study endpoint was the six-month prescription-filling rate.

RESULTS

Across the four six-month periods, prescription-filling rates increased for all categories of medications studied. There were modest progressive increases for lipid-lowering agents, statins, -blockers, angiotensin-converting-enzyme Inhibitors, and angiotensin-receptor blockers. The antithrombotic-filling rate averaged 88.5%. Filling rates for aspirin were much higher than for aspirin alternatives.

CONCLUSION

Prescription-filling rates for post-CABG medications in VA facilities were generally high and suggested compliance with guidelines for the prevention of cardiovascular events.

Predictors of health-related quality of life after coronary artery bypass surgery

BACKGROUND

Little is known about the determinants of health-related quality of life after coronary artery bypass surgery. We determined the predictors of overall physical and mental health status 6 months after the operation.

METHODS

We evaluated 1,973 patients enrolled in a multicenter Veterans Affairs prospective cohort study who completed preoperative and 6-month postoperative Short Form-36 (SF-36) health status surveys. Multiple linear regression was used to identify the significant independent predictors of 6-month physical and mental component summary scores from the SF-36.

RESULTS

In multivariable analyses adjusting for baseline health status, significant predictors of postoperative physical health status were a history of neurologic disease, peripheral vascular disease, chronic obstructive pulmonary disease, hypertension, current smoking, forced expiratory volume, left ventricular ejection fraction, and serum creatinine. Significant predictors of postoperative mental health status were a history of psychiatric disease, chronic obstructive pulmonary disease, current smoking, age, and New York Heart Association functional class.

CONCLUSIONS

These predictors of health-related quality of life after coronary artery bypass surgery may be useful for preoperative risk assessment and counseling of patients with regard to anticipated health status outcomes. Factors such as current smoking and psychiatric disease may be targets for interventions to improve health-related quality of life outcomes.

Comparison of short-term mortality risk factors for valve replacement versus coronary artery bypass graft surgery

BACKGROUND

Risk factors for 30-day operative (short-term) mortality following coronary artery bypass graft (CABG only) procedures are well established. However, little is known about how the risk factors for short-term mortality following valve replacement procedures (with or without a CABG procedure performed) compare with CABG only risk factors.

METHODS

Department of Veterans Affairs (VA) records (65,585 records) were collected from October 1991 through March 2001 and analyzed. Risk factors for short-term mortality were compared across three subgroups of patients: CABG only surgery (n = 56,318), aortic valve replacement (AVR) with or without CABG (n = 7450), and mitral valve replacement (MVR) with or without CABG (n = 1817). Multivariable logistic regression analyses were used to compare the relative magnitude of risk for 19 candidate predictor variables across subgroups.

RESULTS

Only three patient baseline characteristics differed significantly in magnitude of risk between the procedure groups. Partially or totally dependent functional status significantly increased the risk of short-term mortality for AVR patients (odds ratio [OR] 1.64, 95% confidence interval [CI] 1.29-2.09) and MVR patients (OR 2.21, 95% CI 1.48-3.30), but not for CABG only patients (OR 1.04, 95% CI 0.93-1.16). Conversely, previous heart surgery and New York Heart Association functional class III or IV symptoms conferred greater magnitude of risk for CABG only patients compared with the valve subgroups.

CONCLUSIONS

Overall, the risk factors for short-term mortality following valve replacement and CABG surgery appear to be relatively consistent. However, clinicians should be aware of the importance of preoperative functional status as a unique predictor of mortality following valve surgery.

Predictors of cognitive decline following coronary artery bypass graft surgery

BACKGROUND

A significant number of patients develop cognitive impairment that persists for months following coronary artery bypass grafting (CABG) surgery. Our objectives were to identify patient-related risk factors, processes of care, and the occurrence of any perioperative complications associated with cognitive decline.

METHODS

Nine hundred thirty-nine patients enrolled in the Processes, Structures, and Outcomes of Care in Cardiac Surgery study undergoing CABG-only surgery at 14 Veterans Administration medical centers between 1992 and 1996 completed a short battery of cognitive tests at baseline and 6-months post-CABG. The composite cognitive score was based on the sum of errors for each individual item in the battery. Multiple linear regression analyses were used to identify independent predictors of the 6-month composite cognitive score.

RESULTS

In multivariable analyses, patient characteristics associated with cognitive decline included cerebrovascular disease (p = 0.009), peripheral vascular disease (p = 0.007), history of chronic disabling neurologic illness (p = 0.016), and living alone (p = 0.049), while the number of years of education (p = 0.001) was inversely related to cognitive decline. After adjustment for baseline patient risk factors, the presence of any postoperative complication(s) (p = 0.001) was also associated with cognitive decline while cardiopulmonary bypass time (p = 0.008) was inversely related to cognitive decline.

CONCLUSIONS

Patients with noncoronary manifestations of atherosclerosis, chronic disabling neurologic illness, or limited social support are at risk for cognitive decline after CABG surgery. In contrast, more years of education were associated with less cognitive decline. Preoperative assessment of risk factors identified in this study may be useful when counseling patients about the risk for cognitive decline following CABG surgery.

Relationship Between Processes of Care and Coronary Bypass Operative Mortality and Morbidity

BACKGROUND

Information is limited regarding the effects of processes of care on cardiac surgical outcomes. Correspondingly, many recommended cardiac surgical processes of care are derived from animal experiments or clinical judgment. This report from the VA Cooperative Study in Health Services, "Processes, Structures, and Outcomes of Cardiac Surgery," focuses on the relationships between 3 process groups (preoperative evaluation, intraoperative care, and supervision by senior physicians) and a composite outcome, perioperative mortality and morbidity.

METHODS

Data on 734 risk, process, and structure variables were collected prospectively on 3,988 patients who underwent coronary artery bypass grafting at 14 VA medical centers between 1992 and 1996. Data reduction was accomplished by examining data completeness and variation across sites and surgeon, using previously published data and clinical judgment. We then applied multivariable logistic regression to the 39 remaining processes of care to determine which were related to the composite outcome after adjusting for 17 patient-related risk factors and controlling for intraoperative complications.

RESULTS

Our first analysis showed several measures of operative duration, the use of inotropic agents, transesophageal echo, lowest systemic temperature, and hemoconcentration/ultrafiltration, to be powerful predictors of the composite outcome. Because the use of inotropic agents and operative duration may be related to an intermediate outcome (eg, intraoperative complications), we performed a second analysis omitting these processes. The use of intraoperative transesophageal echo and hemoconcentration/ultrafiltration remained significantly associated with an increased risk of an event (odds ratios 1.60 and 1.36, respectively).

CONCLUSIONS

Our results viewed in the context of past studies suggest the possibility that inotropic use, TEE, and hemoconcentration/ultrafiltration may have adverse effects on operative outcome. Further evaluation of these processes of care using observational data, as well as randomized trials when feasible, would be of interest.

Adult cardiac surgery during the first 50 years of the Southern Thoracic Surgical Association

This is a review of some of the outstanding adult cardiac surgical papers presented during the first 50 years of the Southern Thoracic Surgical Association to commemorate the 50th Anniversary meeting. Since the founding of the Southern Thoracic Surgical Association in 1954 there have been a total 512 adult cardiac surgery and great vessels papers presented, 138 from 1954 to 1970, 157 from 1971 to 1986, and 217 from 1987 to 2002. Since 1964 most of these papers have been published in The Annals of Thoracic Surgery. Forty-three papers were reviewed, the first having been presented in 1956 and the last in 2002. Not all of the papers could be located but the vast majority were retrievable and reviewed. This paper presents a broad spectrum of adult cardiac surgery beginning with early pump technology, early myocardial revascularization including the Vineberg procedure followed by coronary bypass as we know it today, valvular surgery, including several papers on aortic valve homograft and autograft procedures, ventricular aneurysms, aortic aneurysms and aortic dissections. Evaluations of various valve prostheses, cardiac transplantation, mitral valve reconstruction, quality assurance in cardiac surgery, neurobehavioral outcome after cardiac surgery, endocarditis and off-pump coronary bypass surgery were reviewed. We hope that this article is representative of the broad spectrum of issues that have characterized the specialty of cardiothoracic surgery over the second half of the 20th century and the beginning of the 21st century.

Atherogenic effects of chlamydia pneumoniae: refuting the innocent bystander hypothesis

OBJECTIVE

Serologic evidence of Chlamydia pneumoniae infection and atherosclerosis was first demonstrated in patients with ischemic heart disease in 1988. Subsequently, the organism has been detected in several cardiovascular lesions. Outside of observational reports, few studies mechanistically link vascular infection with C. pneumoniae and atherogenesis. To better define its pathophysiologic role, we examined the influence of C. pneumoniae infection of human vascular smooth muscle cells on vascular smooth muscle cell proliferation, cell-cycle protein expression, and inflammatory cytokine release.

METHODS

Human aortic vascular smooth muscle cells were inoculated with C. pneumoniae in culture. Proliferation was assessed by mitochondrial activity, direct cell counting, and immunohistochemical staining for proliferating cell nuclear antigen. Electromobility gel shift assays probed for the antiproliferative cell-cycle protein p53. Supernatants were assayed for the mitogens interleukin-6 and interleukin-8 by enzyme-linked immunosorbent assay.

RESULTS

After C. pneumoniae inoculation, vascular smooth muscle cell proliferation increased 2-fold by mitochondrial activity and more than 3-fold by cell numbers. C. pneumoniae infection promoted a 3-fold increase in proliferating cell nuclear antigen expression, which was associated with decreased nuclear binding of p53. Compared with control, C. pneumoniae inoculation resulted in a 2.5-fold increase in released interleukin-6 and interleukin-8. In each experiment, the influence of C. pneumoniae was abrogated by concomitant treatment with the macrolide antibiotic azithromycin.

CONCLUSIONS

C. pneumoniae induced human vascular smooth muscle cell proliferation and proliferating cell nuclear antigen expression, down-regulated p53, and promoted release of prototypical atherogenic cytokines. These in vitro findings indicate that C. pneumoniae is more than an innocent bystander, rather it is a pathophysiologic participant in atherogenesis warranting elimination.

Use of continuous quality improvement to increase use of process measures in patients undergoing coronary artery bypass graft surgery: a randomized controlled trial

CONTEXT

A rigorous evaluation of continuous quality improvement (CQI) in medical practice has not been carried out on a national scale.

OBJECTIVE

To test whether low-intensity CQI interventions can be used to speed the national adoption of 2 coronary artery bypass graft (CABG) surgery process-of-care measures: preoperative beta-blockade therapy and internal mammary artery (IMA) grafting in patients 75 years or older.

DESIGN, SETTING, AND PARTICIPANTS

Three hundred fifty-nine academic and nonacademic hospitals (treating 267 917 patients using CABG surgery) participating in the Society of Thoracic Surgeons National Cardiac Database between January 2000 and July 2002 were randomized to a control arm or to 1 of 2 groups that used CQI interventions designed to increase use of the process-of-care measures.

INTERVENTION

Each intervention group received measure-specific information, including a call to action to a physician leader; educational products; and periodic longitudinal, nationally benchmarked, site-specific feedback.

MAIN OUTCOME MEASURE

Differential incorporation of the targeted care processes into practice at the intervention sites vs the control sites, assessed by measuring preintervention (January-December 2000)/postintervention (January 2001-July 2002) site differences and by using a hierarchical patient-level analysis.

RESULTS

From January 2000 to July 2002, use of both process measures increased nationally (beta-blockade, 60.0%-65.6%; IMA grafting, 76.2%-82.8%). Use of beta-blockade increased significantly more at beta-blockade intervention sites (7.3% [SD, 12.8%]) vs control sites (3.6% [SD, 11.5%]) in the preintervention/postintervention (P =.04) and hierarchical analyses (P<.001). Use of IMA grafting also tended to increase at IMA intervention sites (8.7% [SD, 17.5%]) vs control sites (5.4% [SD,15.8%]) (P =.20 and P =.11 for preintervention/postintervention and hierarchical analyses, respectively). Both interventions tended to have more impact at lower-volume CABG sites (for interaction: P =.04 for beta-blockade; P =.02 for IMA grafting).

CONCLUSIONS

A multifaceted, physician-led, low-intensity CQI effort can improve the adoption of care processes into national practice within the context of a medical specialty society infrastructure.

The Society of Thoracic Surgeons: 30-day operative mortality and morbidity risk models

BACKGROUND

Although 30 day risk-adjusted operative mortality (ROM) has been used for quality assessment, it is not sufficient to describe the outcomes after coronary artery bypass grafting (CABG) surgery. Risk-adjusted major morbidity may differentially impact quality of care (as complications occur more frequently than death) and enhance a surgical team's ability to assess their quality. This study identified the preoperative risk factors associated with several complications and a composite outcome (the presence of any major morbidity or 30-day operative mortality or both).

METHODS

For CABG procedures, the 1997 to 1999 Society of Thoracic Surgeons (STS) National Adult Cardiac Surgery Database was used to develop ROM and risk-adjusted morbidity (ROMB) models. Risk factors were selected using standard STS univariate screening and multivariate logistic regression approaches. Risk model performance was assessed. Across STS participating sites, the association of observed-to-expected (O/E) ratios for ROM and ROMB was evaluated.

RESULTS

The 30-day operative death and major complication rates for STS CABG procedures were 3.05% and 13.40%, respectively (503,478 CABG procedures), including stroke (1.63%), renal failure (3.53%), reoperation (5.17%), prolonged ventilation (5.96%), and sternal infection (0.63%). Risk models were developed (c-indexes for stroke [0.72], renal failure [0.76], reoperation [0.64], prolonged ventilation [0.75], sternal infection [0.66], and the composite endpoint [0.71]). Only a slight correlation was found, however, between ROMB and ROM indicators.

CONCLUSIONS

Used in combination, ROMB and ROM may provide the surgical team with additional information to evaluate the quality of their care as well as valuable insights to allow them to focus on areas for improvement.

Variation in mortality risk factors with time after coronary artery bypass graft operation

BACKGROUND

Differences in mortality risk factor sets during different time periods (eg, short-term versus intermediate-term) after coronary artery bypass grafting have been reported. However, little is known about the time-varying effects of mortality risk factors after the operation.

METHODS

We analyzed 11,815 veterans who had coronary artery bypass grafting at any of the 43 Veterans Affairs cardiac surgery centers from October 1997 to September 1999. Time-varying effects of 14 mortality risk factors during the 210 days after coronary artery bypass grafting were evaluated using Cox B-spline regression, which provides an estimate of risk for each variable for each day after operation.

RESULTS

Eight variables showed significant time-varying effects after operation. The effect of prior heart operation was very high immediately after operation, but disappeared within 1 week. Three other cardiac variables (prior myocardial infarction, preoperative intraaortic balloon pump, and Canadian Cardiovascular Society anginal class III or IV) also conferred the highest risk on the day of operation and decreased thereafter. In contrast, the four time-varying noncardiac risk variables (age, impaired functional status, chronic obstructive pulmonary disease, and renal dysfunction) showed little or no association with mortality immediately after operation, but had increasing impact during the several months after operation.

CONCLUSIONS

A sizable number of mortality risk factors have time-varying effects after coronary artery bypass grafting. Several cardiac risk factors have peak impact immediately after operation but dissipate thereafter. Several noncardiac risk factors confer little risk immediately after operation, but these risks increase during several months. This information may help clinicians focus management strategies for patients during the 7 months after operation.

The impact of ethnicity on outcomes following coronary artery bypass graft surgery in the Veterans Health Administration

OBJECTIVES

We evaluated the effect of African American (AA) and Hispanic American (HA) ethnicity on mortality and complications following coronary artery bypass graft (CABG) surgery in the Veterans Health Administration (VHA).

BACKGROUND

Few studies have examined the impact of ethnicity on outcomes following cardiovascular procedures.

METHODS

This study included all 29,333 Caucasian, 2,570 AA, and 1,525 HA patients who underwent CABG surgery at any one of the 43 VHA cardiac surgery centers from January 1995 through March 2001. We evaluated the relationship between ethnicity (AA vs. Caucasian and HA vs. Caucasian) and 30-day mortality, 6-month mortality, and 30-day complications, adjusting for a wide array of demographic, cardiac, and noncardiac variables.

RESULTS

After adjustment for baseline characteristics, AA and Caucasian patients had similar 30-day (AA/Caucasian odds ratio [OR] 1.07; 95% confidence interval [CI] 0.84 to 1.35; p = 0.59) and 6-month mortality risk (AA/Caucasian OR 1.10; 95% CI 0.91 to 1.34; p = 0.31). However, among patients with low surgical risk, AA ethnicity was associated with higher mortality (OR 1.52, CI 1.10 to 2.11, p = 0.01), and AA patients were more likely to experience complications following surgery (OR 1.28; 95% CI 1.14 to 1.45; p < 0.01). In contrast, HA patients had lower 30-day (HA/Caucasian OR 0.70; 95% CI 0.49 to 0.98; p = 0.04) and 6-month mortality risk (HA/Caucasian OR 0.66; 95% CI 0.50 to 0.88; p < 0.01) than Caucasian patients.

CONCLUSIONS

Ethnicity does not appear to be a strong risk factor for adverse outcomes following CABG surgery in the VHA. Future studies are needed to determine why AA patients have more complications, but ethnicity should not affect the decision to offer the operation.

Validation of European System for Cardiac Operative Risk Evaluation (EuroSCORE) in North American cardiac surgery

OBJECTIVE

To assess the performance of the European System for Cardiac Operative Risk Evaluation (EuroSCORE) when applied in a North American cardiac surgical population.

METHODS

The simple additive EuroSCORE model was applied to predict operative mortality (in-hospital or 30-day) in 401684 patients undergoing coronary or valve surgery in 1998 and 1999 as well as in 188913 patients undergoing surgery in 1995 in the Society of Thoracic Surgeons (STS) database.

RESULTS

The proportion of isolated coronary artery bypass grafting (CABG) was greater in STS patients (84%) than in Europe (65%). STS patients were also older (mean age 65.3 versus 62.5), and had more diabetes (30 versus 17%) and prior cardiac surgery (11 versus 7%). Other comorbidity was also significantly more prevalent in STS patients. EuroSCORE predicted overall mortality was virtually identical to the observed mortality (1998/1999: predicted 3.994%, observed 3.992%; 1995: observed and predicted 4.156%). Predicted mortality also closely matched observed mortality across the risk groups. Discrimination was good to very good for the population overall and for isolated CABG in both time periods, with the area under the receiver operating characteristic curve between 0.75 and 0.78.

CONCLUSION

Despite substantial demographic differences between Europe and North America, EuroSCORE performs very well in the STS database, and can be recommended as a simple, additive risk stratification system on both sides of the Atlantic.

Standard versus fiberoptic pulmonary artery catheterization for cardiac surgery in the Department of Veterans Affairs: a prospective, observational, multicenter analysis

BACKGROUND

Controversy exists regarding the utility of continuous monitoring of mixed venous oxygen saturation (STvo2) during cardiac surgery. During a multicenter, prospective, observational study in the Department of Veterans Affairs (Cooperative Study #5), frequency of use of standard pulmonary artery catheterization (PAC) and STvo2-PAC was recorded. Here the authors relate these data to clinical outcomes.

METHODS

Logistic and Cox regression models evaluating the association of PAC type with mortality, one or more postoperative complications, cardiac complications, time to extubation, and intensive care unit length of stay were constructed. The number of thermodilution cardiac outputs and arterial blood gas analyses performed in the first 24 h postoperatively were compared.

RESULTS

Data from 3,265 patients undergoing myocardial revascularization (81.7%) or valve replacement-repair (18.3%) were considered. STvo2-PAC was used in 49% and PAC in 51% of patients. In the 14 hospitals, STvo2-PAC was used in all patients in four, in some patients in four, and never in six. No association of STvo2-PAC use with outcome were observed aside from unexplained hospital level effects. A small but statistically significant reduction in the number of arterial blood gas analyses (8 +/- 3 vs. 10 +/- 4, P < 0.0001, STvo2-PAC vs. PAC, respectively) and thermodilution cardiac outputs (14 +/- 8 vs. 15 +/- 9, P < 0.0001, STvo2-PAC vs. PAC, respectively) was observed with use of STvo2-PAC.

CONCLUSIONS

Despite higher cost, STvo2-PAC was commonly used in this cohort. Our analysis failed to detect associations with improved outcomes aside from a small reduction in resource utilization. The precise role of STvo2-PAC remains uncertain.

A decade of change--risk profiles and outcomes for isolated coronary artery bypass grafting procedures, 1990-1999: a report from the STS National Database Committee and the Duke Clinical Research Institute. Society of Thoracic Surgeons

BACKGROUND

The Society of Thoracic Surgeons National Adult Cardiac Database is the largest voluntary clinical database in medicine. Using this database we examined changes in the risk profile of patients undergoing isolated coronary artery bypass grafting (CABG) and their outcomes during the decade 1990 to 1999.

METHODS

Trends in 23 preoperative risk factors were tracked for CABG cases during this decade. Using a multivariate logistic risk model, we also determined the degree to which operative risk and risk-adjusted operative mortality changed during this 10-year interval.

RESULTS

Between 1990 and 1999, 1,154,486 patient records were harvested by the Society of Thoracic Surgeons National Adult Cardiac Database for isolated CABG procedures performed at 522 Society of Thoracic Surgeons participant sites in the United States and Canada. Over time, CABG patients were more likely to be older (mean age 63.7 in 1990, 65.1 in 1999), of female gender (25.7% women in 1990, 28.7% in 1999), and have a history of smoking, diabetes mellitus, renal failure, hypertension, stroke, chronic lung disease, New York Heart Association functional class IV, and three-vessel disease (p < 0.0001). Patients' predicted operative risk increased by 30.1%, from 2.6% in 1990 to 3.4% in 1999. Despite higher risk, observed operative mortality decreased by 23.1%, from 3.9% in 1990 to 3.0% in 1999 (p < 0.0001). During the decade, a Medicare-aged subset (n = 629,174) experienced similar increases in risk and declines in mortality.

CONCLUSIONS

Patients referred for isolated CABG are significantly older, sicker, and have a higher risk than a decade ago. Despite this, CABG mortality rates have declined substantially. These results highlight the excellent progress in the care of CABG patients achieved during the past decade.

Effect of definition of mortality on hospital profiles

BACKGROUND

Hospitals are ranked based on risk-adjusted measures of postoperative mortality, but definitions differ about which deaths following surgery should be included.

OBJECTIVE

To determine whether varying the case definition of deaths following surgery that are included in coronary artery bypass surgery quality assessment affects the identification of outlier hospitals.

RESEARCH DESIGN

The study used a prospective cohort design.

SUBJECTS

A total of 15,288 patients undergoing coronary artery bypass surgery without other cardiac procedures from October 1993 to March 1996 at all (N = 43) Veterans Affairs hospitals that conduct cardiac surgery.

MEASURES

The first measure included any death occurring within 30 days after surgery, regardless of cause, in or out of the hospital (30-day mortality). The second measure included 30-day mortality plus any death occurring 30 days to 6 months after surgery that was judged to be a direct result of a perioperative complication of the surgery (all procedure-related mortality).

RESULTS

Hospital performance as assessed by the two different definitions of death varied substantially. The rankings of hospitals differed for 86% (37/43) of hospitals. Twenty-one percent (9/43) changed their quartile of rank, and five hospitals changed their outlier status. The correlation of observed-to-expected ratios was high (r = 0.96), but there was disagreement of outlier status (kappa = 0.71).

CONCLUSIONS

Judgments regarding the quality of a hospital's performance of coronary artery bypass surgery vary depending on the definition of postoperative mortality that is used. Further research is needed to assess what definition is most appropriate to identify quality of care problems.

Quality improvement in cardiac care

Quality improvement in cardiac care has made considerable progress over the past 30 years. During that period, there has been the development of multi-institutional databases to monitor outcomes following cardiothoracic surgery. These databases initially began using only volume and unadjusted operative (30-day) mortality as outcome criteria. There has been a progressive increase in their sophistication, with the building of risk models based on preoperative variables, which accurately predict the risk of adverse outcomes. Other outcomes have been added including risk-adjusted mortality and morbidity; efficiency outcomes such as length of stay, quality of life, functional health status, neuropsychological outcomes; and long-term outcomes.

Changes in health-related quality of life following coronary artery bypass graft surgery

BACKGROUND

There are limited data to help clinicians identify patients likely to have an improvement in quality of life following CABG surgery. We evaluated the relationship between preoperative health status and changes in quality of life following CABG surgery.

METHODS

We evaluated 1,744 patients enrolled in the VA Cooperative Processes, Structures, and Outcomes in Cardiac Surgery study who completed preoperative and 6-month postoperative Short Form-36 (SF-36) surveys. The primary outcome was change in the Mental Component Summary (MCS) and Physical Component Summary (PCS) scores from the SF-36.

RESULTS

On average, physical and mental health status improved following the operation. Preoperative health status was the major determinant of change in quality of life following surgery, independent of anginal burden and other clinical characteristics. Patients with MCS scores less than 44 or PCS scores less than 38 were most likely to have an improvement in quality of life. Patients with higher preoperative scores were unlikely to have an improvement in quality of life.

CONCLUSIONS

Patients with preoperative health status deficits are likely to have an improvement in their quality of life following CABG surgery. Alternatively, patients with relatively good preoperative health status are unlikely to have a quality of life benefit from surgery and the operation should primarily be performed to improve survival.

A decade's experience with quality improvement in cardiac surgery using the Veterans Affairs and Society of Thoracic Surgeons national databases

OBJECTIVE

To review the Department of Veteran Affairs (VA) and the Society of Thoracic Surgeons (STS) national databases over the past 10 years to evaluate their relative similarities and differences, to appraise their use as quality improvement tools, and to assess their potential to facilitate improvements in quality of cardiac surgical care.

SUMMARY BACKGROUND DATA

The VA developed a mandatory risk-adjusted database in 1987 to monitor outcomes of cardiac surgery at all VA medical centers. In 1989 the STS developed a voluntary risk-adjusted database to help members assess quality and outcomes in their individual programs and to facilitate improvements in quality of care.

METHODS

A short data form on every veteran operated on at each VA medical center is completed and transmitted electronically for analysis of unadjusted and risk-adjusted death and complications, as well as length of stay. Masked, confidential semiannual reports are then distributed to each program's clinical team and the associated administrator. These reports are also reviewed by a national quality oversight committee. Thus, VA data are used both locally for quality improvement and at the national level with quality surveillance. The STS dataset (217 core fields and 255 extended fields) is transmitted for each patient semiannually to the Duke Clinical Research Institute (DCRI) for warehousing, analysis, and distribution. Site-specific reports are produced with regional and national aggregate comparisons for unadjusted and adjusted surgical deaths and complications, as well as length of stay for coronary artery bypass grafting (CABG), valvular procedures, and valvular/CABG procedures. Both databases use the logistic regression modeling approach. Data for key processes of care are also captured in both databases. Research projects are frequently carried out using each database.

RESULTS

More than 74,000 and 1.6 million cardiac surgical patients have been entered into the VA and STS databases, respectively. Risk factors that predict surgical death for CABG are very similar in the two databases, as are the odds ratios for most of the risk factors. One major difference is that the VA is 99% male, the STS 71% male. Both databases have shown a significant reduction in the risk-adjusted surgical death rate during the past decade despite the fact that patients have presented with an increased risk factor profile. The ratio of observed to expected deaths decreased from 1.05 to 0.9 for the VA and from 1.5 to 0.9 for the STS.

CONCLUSION

It appears that the routine feedback of risk-adjusted data on local performance provided by these programs heightens awareness and leads to self-examination and self-assessment, which in turn improves quality and outcomes. This general quality improvement template should be considered for application in other settings beyond cardiac surgery.

Off-pump coronary artery bypass grafting decreases risk-adjusted mortality and morbidity

BACKGROUND

The purpose of this study was to determine whether coronary artery bypass grafting without cardiopulmonary bypass (off-pump CABG) decreases risk-adjusted operative death and major complications after coronary artery bypass grafting in selected patients.

METHODS

Using The Society of Thoracic Surgeons (STS) National Adult Cardiac Surgery Database, procedural outcomes were compared for conventional and off-pump CABG procedures from January 1, 1998, through December 31, 1999. Mortality and major complications were examined, both as unadjusted rates and after adjusting for known base line patient risk factors.

RESULTS

A total of 126 experienced centers performed 118,140 total CABG procedures. The number of off-pump CABG cases was 11,717 cases (9.9% of total cases). The use of an off-pump procedure was associated with a decrease in risk-adjusted operative mortality from 2.9% with conventional CABG to 2.3% in the off-pump group (p < 0.001). The use of an off-pump procedure decreased the risk-adjusted major complication rate from 14.15% with conventional CABG to 10.62% in the off-pump group (p < 0.0001). Patients receiving off-pump procedures were less likely to die (adjusted odds ratio 0.81, 95% CI 0.70 to 0.91) and less likely to have major complications (adjusted odds ratio 0.77, 95% CI 0.72 to 0.82).

CONCLUSIONS

Off-pump CABG is associated with decreased mortality and morbidity after coronary artery bypass grafting. Off-pump CABG may prove superior to conventional CABG in appropriately selected patients.

Off-pump coronary artery bypass is associated with improved risk-adjusted outcomes

BACKGROUND

The impact of off-pump median sternotomy coronary artery bypass grafting procedures on risk-adjusted mortality and morbidity was evaluated versus on-pump procedures.

METHODS

Using the Department of Veterans Affairs Continuous Improvement in Cardiac Surgery Program records from October 1997 through March 1999, nine centers were designated as having experience (with at least 8% coronary artery bypass grafting procedures performed off-pump). Using all other 34 Veterans Affairs cardiac surgery programs, baseline logistic regression models were built to predict risk of 30-day operative mortality and morbidity. These models were then used to predict outcomes for patients at the nine study centers. A final model evaluated the impact of the off-pump approach within these nine centers adjusting for preoperative risk.

RESULTS

Patients treated off-pump (n = 680) versus on-pump (n = 1,733) had lower complication rates (8.8% versus 14.0%) and lower mortality (2.7% versus 4.0%). Risk-adjusted morbidity and mortality were also improved for these patients (0.52 and 0.56 multivariable odds ratios for off-pump versus on-pump, respectively, p < 0.05).

CONCLUSIONS

An off-pump approach for coronary artery bypass grafting procedures is associated with lower risk-adjusted morbidity and mortality.

Prediction of operative mortality after valve replacement surgery

OBJECTIVES

We sought to develop national benchmarks for valve replacement surgery by developing statistical risk models of operative mortality.

BACKGROUND

National risk models for coronary artery bypass graft surgery (CABG) have gained widespread acceptance, but there are no similar models for valve replacement surgery.

METHODS

The Society of Thoracic Surgeons National Cardiac Surgery Database was used to identify risk factors associated with valve surgery from 1994 through 1997. The population was drawn from 49,073 patients undergoing isolated aortic valve replacement (AVR) or mitral valve replacement (MVR) and from 43,463 patients undergoing CABG combined with AVR or MVR. Two multivariable risk models were developed: one for isolated AVR or MVR and one for CABG plus AVR or CABG plus MVR.

RESULTS

Operative mortality rates for AVR, MVR, combined CABG/AVR and combined CABG/ MVR were 4.00%, 6.04%, 6.80% and 13.29%, respectively. The strongest independent risk factors were emergency/salvage procedures, recent infarction, reoperations and renal failure. The c-indexes were 0.77 and 0.74 for the isolated valve replacement and combined CABG/valve replacement models, respectively. These models retained their predictive accuracy when applied to a prospective patient population undergoing operation from 1998 to 1999. The Hosmer-Lemeshow goodness-of-fit statistic was 10.6 (p = 0.225) for the isolated valve replacement model and 12.2 (p = 0.141) for the CABG/valve replacement model.

CONCLUSIONS

Statistical models have been developed to accurately predict operative mortality after valve replacement surgery. These models can be used to enhance quality by providing a national benchmark for valve replacement surgery.