BACKGROUND: After cardiac surgery, acute renal failure (ARF) requiring dialysis develops in 1% to 5% of patients and is strongly associated with perioperative morbidity and mortality. Prior studies have attempted to identify predictors of ARF but have had insufficient power to perform multivariable analyses or to develop risk stratification algorithms. METHODS AND RESULTS: We conducted a prospective cohort study of 43 642 patients who underwent coronary artery bypass or valvular heart surgery in 43 Department of Veterans Affairs medical centers between April 1987 and March 1994. Logistic regression analysis was used to identify independent predictors of ARF requiring dialysis. A risk stratification algorithm derived from recursive partitioning was constructed and was validated on an independent sample of 3795 patients operated on between April and December 1994. The overall risk of ARF requiring dialysis was 1.1%. Thirty-day mortality in patients with ARF was 63.7%, compared with 4.3% in patients without ARF. Ten clinical variables related to baseline cardiovascular disease and renal function were independently associated with the risk of ARF. A risk stratification algorithm partitioned patients into low-risk (0.4%), medium-risk (0.9% to 2.8%), and high-risk (> or = 5.0%) groups on the basis of several of these factors and their interactions. CONCLUSIONS: The risk of ARF after cardiac surgery can be accurately quantified on the basis of readily available preoperative data. These findings may be used by physicians and surgeons to provide patients with improved risk estimates and to target high-risk subgroups for interventions aimed at reducing the risk and ameliorating the consequences of this serious complication.

Acute Kidney Injury↗

PubMed1997

Measurement of apoptosis in heterogenous cell populations.

The increasing interest in programmed cell death has created the need to measure apoptosis in complex cell systems. We have combined the use of fluorescent antibodies with the Hoechst 33342/propidium iodide system in order to quantitate programmed cell death in fractions of heterogenous cell populations. Here we describe the analysis of T-cell apoptosis after ligation of the T-cell antigen receptor by superantigen in vitro and ex vivo. This technique can separate cells according to seven parameters, fluorescence caused by FITC, PE, allophycocyanin, incorporation of Hoechst 33342, PI, forward scatter, and side scatter, and it allows determination of elevated Hoechst 33342 uptake in less than 10% of the cell population.

Animals↗

PubMed1997

Best practices for managing surgical services: the role of coordination.

Growing evidence exists that patient outcomes are related to how effectively health care organizations coordinate work responsibilities among their staffs. However, information is lacking on actual practices that can be used to achieve effective coordination. This article reports on a National Veterans Affairs Surgical Risk Study, in which the authors studied the coordination practices of 20 surgical services that, based on risk-adjusted mortality and morbidity rates, occupied different ends of the patient outcomes continuum.

Benchmarking↗

PubMed1997

Outcomes of acute myocardial infarction in the Department of Veterans Affairs: does regionalization of health care work?

OBJECTIVES: This study examines the association between the regional availability of cardiac technology and outcomes of care for patients admitted to Department of Veterans Affairs (VA) hospitals. Patients using the VA regional medical system initially are admitted to a hospital with or without the on-site availability of technology-intensive cardiac services. METHODS: The authors identified male veterans (n = 24,229) discharged from VA hospitals with a primary diagnosis of acute myocardial infarction (AMI) from January 1, 1988 through December 31, 1990. Analyses of mortality up to 2 years after AMI and the use of cardiac procedures were stratified by the type of VA hospitals to which patients initially were admitted. Logistic regression models adjusted for age, race, marital status, hospitalization in previous year, comorbidities, cardiac complications coded, and year of AMI. RESULTS: Adjusted mortality was significantly higher for patients initially admitted to hospitals without on-site cardiac technology at: 2 days (odds ratio [OR] 0.70; 95% confidence interval [CI] 0.62-0.81), 90 days (OR 0.78; 95% CI 0.73-0.85); 1 year (OR 0.87, 95% CI 0.81-0.93); and 2 years (OR 0.86, 95% CI 0.81-0.92) compared with hospitals with on-site cardiac technology (ie, coronary angioplasty and cardiac surgery facilities). Patients initially admitted to hospitals without on-site cardiac technology also were less likely to undergo cardiac procedures than patients admitted to hospitals with on-site cardiac technology. CONCLUSIONS: The regional distribution of cardiac technology may restrict patient access to technology-intensive services and to "equally good medical care." Policies that promote regionalization of medical services should consider carefully the distribution of benefits and burdens to patients.

Cardiology Service, Hospital↗

PubMed1997

Discharge destination and repeat hospitalizations.

OBJECTIVES: Is discharge destination a determinant of readmission? Studies to date have been inconclusive. The primary purpose of this study was to identify the role of discharge destination in the occurrence of repeat hospitalizations for a national sample of patients discharged from Veterans Health Administration (VHA) hospitals. METHODS: The authors studied a 20% random sample of individual patients, 65 years of age or older, with either chronic obstructive pulmonary disease, stroke, or dementia who were discharged from a Veterans Health Administration hospital in 1988. All data for the study were obtained from secondary administrative sources. Multiple sources were used to determine discharge destination. The authors focused on personal home versus nursing home discharge destination. Both VHA and Medicare discharge data were used to track hospital readmissions. Proportional hazards regression models were used to examine the independent association of discharge destination with time to readmission within 30 days, 6 months, 1 year, and 2 years of discharge, adjusting for severity, other clinical and demographic characteristics, and censoring deaths. RESULTS: After adjustment and including out-of-system (Medicare) use, we found that patients with chronic obstructive pulmonary disease and patients with dementia who were discharged to nursing homes (community and Veterans Health Administration, respectively) were less likely to be readmitted within 30 days after discharge than patients discharged to personal homes. CONCLUSIONS: These findings have important implications for adjusting hospital performance profiles based on discharge destination and for focussing efforts to reduce the frequency and associated costs of hospital readmissions.

Aftercare↗

PubMed1997

Where do elderly veterans obtain care for acute myocardial infarction: Department of Veterans Affairs or Medicare?

OBJECTIVE: To examine Department of Veterans Affairs (VA) and Medicare hospitalizations for elderly veterans with acute myocardial infarction (AMI), their use of cardiac procedures in both systems, and patient mortality. DATA SOURCES: Merging of inpatient discharge abstracts obtained from VA Patient Treatment Files (PTF) and Medicare MedPAR Part A files. STUDY DESIGN: A retrospective cohort study of male veterans 65 years or older who were prior users of the VA medical system (veteran-users) and who were initially admitted to a VA or Medicare hospital with a primary diagnosis of AMI at some time from January 1, 1988 through December 31, 1990 (N = 25,312). We examined the use of cardiac catheterization, coronary bypass surgery, and percutaneous transluminal coronary angioplasty in the 90 days after initial admission for AMI in both VA and Medicare systems, and survival at 30 days, 90 days, and one year. Other key measures included patient age, race, marital status, comorbidities, cardiac complications, prior utilization, and the availability of cardiac technology at the admitting hospital. PRINCIPAL FINDINGS: More than half of veteran-users (54 percent) were initially hospitalized in a Medicare hospital when they suffered an AMI. These Medicare index patients were more likely to receive cardiac catheterization (OR 1.24, 95% C.I. 1.17-1.32), coronary bypass surgery (OR 2.01, 95% C.I. 1.83-2.20), and percutaneous transluminal coronary angioplasty (OR 2.56, 95% C.I. 2.30-2.85) than VA index patients. Small proportions of patients crossed over between systems of care for catheterization procedures (VA to Medicare = 3.3%, and Medicare to VA = 5.1%). Many VA index patients crossed over to Medicare hospitals to obtain bypass surgery (27.6 percent) or coronary angioplasty (12.1 percent). Mortality was not significantly different between veteran-users who were initially admitted to VA versus Medicare hospitals. CONCLUSIONS: Dual-system utilization highlights the need to look at both systems of care when evaluating access, costs, and quality either in VA or in Medicare systems. Policy changes that affect access to and utilization of one system may lead to unpredictable results in the other.

Aged↗

PubMed1997

Risk adjustment of the postoperative mortality rate for the comparative assessment of the quality of surgical care: results of the National Veterans Affairs Surgical Risk Study.

BACKGROUND: The National Veterans Affairs Surgical Risk Study was designed to collect reliable, valid data on patient risk and outcomes for major surgery in the Veterans Health Administration and to report comparative risk-adjusted postoperative mortality rates for surgical services in Veterans Health Administration. STUDY DESIGN: This cohort study was conducted in 44 Veterans Affairs Medical Centers. Included were 87,078 major noncardiac operations performed under general, spinal, or epidural anesthesia between October 1, 1991, and December 31, 1993. The main outcomes measure was all-cause mortality within 30 days after the index procedure. Multivariable logistic regression risk-adjustment models for all operations and for eight surgical subspecialties were developed. Risk-adjusted surgical mortality rates were expressed as observed-to-expected ratios and were compared with unadjusted 30-day postoperative mortality rates. RESULTS: Patient risk factors predictive of postoperative mortality included serum albumin level, American Society of Anesthesia class, emergency operation, and 31 additional preoperative variables. Considerable variability in unadjusted mortality rates for all operations was observed across the 44 hospitals (1.2-5.4%). After risk adjustment, observed-to-expected ratios ranged from 0.49 to 1.53. Rank order correlation of the hospitals by unadjusted and risk-adjusted mortality rates for all operations was 0.64. Ninety-three percent of the hospitals changed rank after risk adjustment, 50% by more than 5 and 25% by more than 10. CONCLUSIONS: The Department of Veterans Affairs has successfully implemented a system for the prospective collection and comparative reporting of risk-adjusted postoperative mortality rates after major noncardiac operations. Risk adjustment had an appreciable impact on the rank ordering of the hospitals and provided a means for monitoring and potentially improving the quality of surgical care.

Cohort Studies↗

PubMed1997

Risk adjustment of the postoperative morbidity rate for the comparative assessment of the quality of surgical care: results of the National Veterans Affairs Surgical Risk Study.

BACKGROUND: The National Veterans Affairs Surgical Risk Study was designed to collect reliable, valid data on patient risk and outcomes for major surgery in the Veterans Health Administration and to report comparative risk-adjusted postoperative mortality and morbidity rates for surgical services in the Veterans Health Administration. STUDY DESIGN: This was a cohort study conducted at 44 Veterans Affairs Medical Centers closely affiliated with university medical centers. Included were 87,078 major noncardiac operations performed under general, spinal, or epidural anesthesia between October 1, 1991, and December 31, 1993. The main outcomes measures in this report are 21 postoperative adverse events (morbidities) occurring within 30 days after the index procedure. Multivariable logistic regression risk-adjustment models for all operations and for eight surgical subspecialties were developed. RESULTS: Patient risk factors predictive of postoperative morbidity included serum albumin level, American Society of Anesthesia class, the complexity of the operation, and 17 other preoperative risk variables. Wide variation in the unadjusted rates of one or more postoperative morbidities for all operations was observed across the 44 hospitals (7.4-28.4%). Risk-adjusted observed-to-expected ratios ranged from 0.49 to 1.46. The Spearman rank order correlation between the ranking of the hospitals based on unadjusted morbidity rates and risk-adjusted observed-to-expected ratios for all operations was 0.87. There was little or no correlation between the rank order of the hospitals by risk-adjusted morbidity and risk-adjusted mortality. CONCLUSIONS: The Department of Veterans Affairs has successfully implemented a system for the prospective collection and comparative reporting of postoperative mortality and morbidity rates after major noncardiac operations. Risk adjustment had only a modest effect on the rank order of the hospitals.

Female↗

PubMed1997

Validating risk-adjusted surgical outcomes: site visit assessment of process and structure. National VA Surgical Risk Study.

BACKGROUND: Risk-adjusted mortality and morbidity rates are often used as measures of the quality of surgical care. This study was conducted to determine the validity of risk-adjusted surgical morbidity and mortality rates as measures of quality of care by assessing the process and structure of care in surgical services with higher-than-expected and lower-than-expected risk-adjusted 30-day mortality and morbidity rates. STUDY DESIGN: A structural survey of 44 Veterans Affairs Medical Center surgical services and site visits to 20 surgical services with higher-than-expected and lower-than-expected risk-adjusted outcomes were conducted. Main outcome measures included assessment of technology and equipment, technical competence of staff, leadership, relationship with other services, monitoring of quality of care, coordination of work, relationship with affiliated institutions, and overall quality of care. RESULTS: Surgical services with lower-than-expected risk-adjusted surgical morbidity and mortality rates had significantly more equipment available in surgical intensive care units than did services with higher-than-expected outcomes (4.3 versus 2.9, p < 0.05). Site-visitor ratings of overall quality of care were significantly higher for surgical services with lower-than-expected morbidity and mortality rates (6.1 versus 4.5 for high outliers, p < 0.05); technology and equipment were rated significantly better among low-outlier services (7.1 versus 4.8 for high outliers, p < 0.001). Masked site-visit teams correctly predicted the outlier status (high versus low) of 17 of the 20 surgical services visited (p < 0.001). CONCLUSIONS: Significant differences in several dimensions of process and structure of the delivery of surgical care are associated with differences in risk-adjusted surgical morbidity and mortality rates among 44 Veterans Affairs Medical Centers.

Hospital Mortality↗

PubMed1996

A 35-year-old pregnant woman considering maternal serum screening and amniocentesis, 1 year later.

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Adult↗