Sundsfjord JA, Dickstein K. Plasma brain natriuretic peptide as an indicator ofleft ventricular systolic function and long-term survival after acute myocardialinfarction. Comparison with plasma atrial natriuretic peptide and N-terminalproatrial natriuretic peptide. Circulation 1996;93:1963–1969.6. Arakawa N, Nakamura M, Aoki H, Hiramori K. Plasma brain natriureticpeptide concentrations predict survival after acute myocardial infarction. J AmColl Cardiol 1996;27:1656–1661.7. Hutchins G, Bulkley B. Infarct expansion versus extension: two differentcomplications of acute myocardial infarction. Am J Coll Cardiol 1978;41:1127–1132.8. McKey R, Pfeffer M, Pasternark R, Markis J, Come P, Nakao S, Alderman J,Ferguson J, Safian R, Grossman W. Left ventricular remodeling after myocardialinfarction: a corollary to infarct expansion. Circulation 1986;74:693–702.9. Rubin SA, Fishbein MC, Swan HJC. Compensatory hypertrophy in the heartafter myocardial infarction. J Am Coll Cardiol 1989;1:1435–1441.10. Hirayama A, Adachi T, Asada S, Mishima M, Nanto S, Kusuoka H,Yamamoto K, Matsumura Y, Hori M, Inoue M, Kodama K. Late reperfusion for

acute myocardial infarction limits the dilatation of left ventricle without thereduction of infarct size. Circulation 1993;88:2565–2574.11. Sheehan F, Bolson E, Dodge H, Mathey D, Schofer J, Woo H. Advantagesand applications of the centerline method for characterizing regional ventricularfunction. Circulation 1986;74:293–305.12. Kono M, Yamauchi M, Tsuji T, Misaka A, Igano K, Ueki K, Fujishima M,Ueda A, Inouye K, Nakao K. An immunoradiometric assay for brain natriureticpeptide in human plasma. Kaku Igaku Gijutsu 1993;13:2–7.13. Pfeffer MA, Pfeffer JM. Ventricular enlargement and reduced survival aftermyocardial infarction. Circulation 1987;75(suppl IV):IV-93–IV-97.14. Pouleur H, Rousseau MF, van Eyll C, Charlier AA. Assessment of regionalleft ventricular relaxation in patients with coronary artery disease: importance ofgeometric factors and changes in wall thickness. Circulation 1984;69:696–702.15. Nagaya N, Nishikimi T, Goto Y, Miyao Y, Kobayashi Y, Morii I, DaikokuS, Matsumoto T, Miyazaki S, Matsuoka H, et al. Plasma brain natriuretic peptideis a biochemical marker for the prediction of progressive ventricular remodelingafter acute myocardial infarction. Am Heart J 1998;135:21–28.

Racial Differences in Outcomes of VeteransUndergoing Coronary Artery Bypass Grafting*

Charles Maynard, PhD, and James L. Ritchie, MD

S ince the 1980s, numerous studies have shown thatAfrican-Americans are less likely to undergo cor-

onary artery bypass grafting (CABG) than their whitecounterparts.1 Even in Department of Veterans Affairs(VA) medical centers, where presumably there isequal access to care, this racial difference in the use ofCABG has been established.2–7 There is evidence thatlesser use of CABG in African-Americans may resultin poorer survival for African-Americans who arecandidates for the procedure.8 However, Peterson etal4 reported that African-American veterans withacute myocardial infarction (AMI) had better short-term and equivalent intermediate survival rates thanwhite veterans despite undergoing fewer CABGs.3 Onthe other hand, Peniston et al7 reported that African-American veterans undergoing cardiac catheterizationhad worse survival than their white counterparts eventhough use of revascularization was similar in the 2groups.6 The purpose of this study was to determinewhether there are racial differences with respect toshort- and long-term outcomes for all veterans under-going CABG in VA medical centers.

• • •We used the national VA Patient Treatment File to

identify veterans who underwent CABG and weredischarged from VA medical centers between October1, 1994, and September 30, 1999. There were 33,449

veterans who underwent bypass surgery during the 5years. CABG was identified by International Classifi-cation of Diseases 9th Revision Clinical Modificationprocedure codes 36.1x, and internal mammary arterygrafting was identified by procedure codes 36.15 or36.16. The racial distribution of these veterans was82% white, 7% African-American, 6% unknown, 4%Hispanic, and 1% other races. For this report, weincluded only white or African-American veterans;persons whose race was unknown or termed “other”were excluded from the analysis.

Baseline demographic characteristics of the 29,918veterans in this study were obtained from the VAPatient Treatment File and included age, gender, mar-ital status, race, and year of procedure. Comorbiditiesincluding myocardial infarction, hypertension, diabe-tes, and chronic pulmonary disease were defined fromInternational Classification of Diseases 9th Revision,Clinical Modification diagnosis codes. Also, a comor-bidity score as proposed by Deyo et al9 wascalculated.

• • •In this study, both short- (30-day) and long-term

outcomes (survival and rehospitalization) were con-sidered. Vital status after hospital discharge was ob-tained from the Patient Treatment File and BeneficiaryIdentification and Record Locator System death file,which is updated quarterly and has good reliability,particularly for veterans who are eligible for cashbenefits.10 Vital status was assessed through Septem-ber 2000. Information about rehospitalization was ob-tained from the Patient Treatment File for the periodOctober 1, 1994, through September 30, 2000. Rea-sons for hospitalization were classified using diagno-sis and procedure codes and included (1) percutaneouscoronary intervention (procedure codes 36.01, 36.02,36.05, or 36.06), (2) repeat CABG (procedure code36.1x), (3) acute myocardial infarction (diagnosiscode 410.xx), (4) unstable angina (diagnosis code

From the Departments of Medicine and Health Services Research andDevelopment, Department of Veterans Affairs, Seattle; and Depart-ments of Medicine and Health Services, University of Washington,Seattle, Washington. This work was funded by a grant from the VAQuality Enhancement Research Initiative Ischemic Heart Disease Cen-ter, Seattle, Washington. Dr. Maynard’s address is: Department ofVeterans Affairs, Health Services Research and Development (152),1660 South Columbian Way, Seattle, Washington 98108. E-mail:cmaynard@u.washington.edu. Manuscript received April 20, 2001;revised manuscript received and accepted May 29, 2001.

*The views expressed in this article are those of the authors and do notnecessarily represent the views of the Department of Veterans Affairs.

893©2001 by Excerpta Medica, Inc. All rights reserved. 0002-9149/01/$–see front matterThe American Journal of Cardiology Vol. 88 October 15, 2001 PII S0002-9149(01)01900-2

411.xx), (5) congestive heart failure (diagnosis code428.x), or (6) any rehospitalization.

Patient characteristics and outcomes were com-pared for African-American and white veterans; thechi-square statistic was used for categorical variablesand the 2-sample t test for continuous variables. Thir-ty-day mortality for the 2 groups was compared usinglogistic regression so that all statistically significantpredictors (p �0.05) listed in Table 1 could be enteredin a stepwise fashion; race was then forced in todetermine its association with 30-day mortality. Thelog-rank statistic was used to compare survival andrehospitalization rates in white and African-Americanveterans. Stepwise proportional-hazards regressionwas used to assess the association between race andsurvival as well as that between race and rehospital-ization.

African-American veterans were 8% of the studypopulation, were slightly younger and less often mar-ried, and were also less likely to receive internalmammary artery grafts (Table 1). As in past studies, alarger proportion of African-Americans had hyperten-sion and/or diabetes and more white veterans hadpulmonary disease, although the Deyo comorbidityscore was similar in the 2 groups (Table 1).

Because the average length ofstay was 18.7 � 21.9 days for Afri-can-American and 16.3 � 28.7 daysfor white veterans (p �0.0001), 30-day mortality was used as the short-term outcome measure. Unadjusted30-day mortality was similar in Af-rican-American and white veterans(3.6% vs 3.5%, p � 0.81). After ad-justment for age, internal mammaryartery grafting, Deyo score, hyper-tension, myocardial infarction,chronic pulmonary disease, and dia-betes mellitus with logistic regres-sion analysis (n � 29,626), 30-daymortality was similar in the 2 groups(odds ratio 1.02, 95% confidence in-terval 0.91 to 1.15).

Two-year survival for African-American veterans was slightlyworse than it was for white veterans(Table 2 and Figure 1). After usingCox regression (n � 29,626) to ad-just for age, Deyo score, internalmammary artery grafting, hyperten-sion, marital status, diabetes melli-tus, myocardial infarction, and gen-der, African-Americans had a 9%higher risk of death than their whitecounterparts (Table 2).

At 2 years, 55% of African-Americans and 53% of white veter-ans were rehospitalized for any rea-son in VA medical centers (Table 2).Although this difference was statisti-cally significant, the overall differ-ence of 2% was minimal, and in Cox

proportional-hazards regression analysis, the 95%confidence interval included 1.0. Two-year rehospital-ization rates for repeat CABG were �1% in bothgroups, and rates for percutaneous coronary interven-tions were similar in African-American and whiteveterans. Rehospitalization rates for unstable anginawere slightly higher for African-Americans, but thisdifference was not statistically significant in multivar-iate analysis.

In this study of African-American and white vet-erans undergoing CABG, adjusted 30-day mortalitywas similar in the 2 groups, although 2-year survivalwas 9% lower in African-Americans veterans. How-ever, the absolute differences for 30-day and 2-yearsurvival rates were 0.1% and 2%, respectively. Rehos-pitalization rates were also slightly higher in African-Americans, but were generally only 1% to 2% higher.Because of the large sample size, the survival differ-ence was statistically significant but had minimal clin-ical significance. A similar finding occurred in ourstudy of racial differences in veterans undergoingpercutaneous coronary interventions.11 Also, African-Americans were less likely to receive internal mam-mary artery grafts, although we have no explanationfor this finding.

TABLE 2 Cumulative Two-Year Survival and Rehospitalization Rates

Outcome African-American WhiteUnadjusted

p ValueAdjusted HazardRatio with 95% CI

Survival 87% 89% 0.01 1.09 (1.03–1.14)Percutaneous coronary

intervention3% 2% 0.69 1.01 (0.90–1.13)

Acute myocardial infarction 4% 3% 0.06 1.06 (0.97–1.16)Unstable angina 9% 8% 0.007 1.06 (1.00–1.13)Congestive heart failure 15% 14% 0.42 1.02 (0.97–1.07)Any rehospitalization 55% 53% 0.02 1.03 (1.00–1.05)

CI � confidence interval.

TABLE 1 Race Differences in Baseline Characteristics

VariableAfrican-American

(n � 2,380)White

(n � 27,439) p Value

Age (yrs) 63 � 10 64 � 9 �0.0001Year of procedure 0.027

1995 20% 21%1996 20% 22%1997 21% 21%1998 18% 19%1999 20% 18%

Men 99% 99% 0.82Married 50% 61% �0.0001Acute myocardial infarction 8% 8% 0.99Systemic hypertension 69% 57% �0.0001Pulmonary disease 11% 18% �0.0001Diabetes mellitus 34% 30% �0.0001Deyo comorbidity score 0.08

0 30% 30%1 34% 34%2 19% 20%3 10% 9%�4 7% 6%

Internal mammary artery graft 60% 67% �0.0001

894 THE AMERICAN JOURNAL OF CARDIOLOGY� VOL. 88 OCTOBER 15, 2001

Recent results from the Society of Thoracic Sur-geons indicated that the risk of 30-day mortality was26% higher in 14,359 African-American men whounderwent coronary artery bypass surgery.12 The in-vestigators of this study concluded, however, that thatthe absolute mortality difference of 0.7% was small,and that patients should be referred to CABG on thebasis of clinical characteristics and not race. In thepresent study, long-term survival was slightly worsefor African-Americans, whereas in other settings, Af-rican-Americans had considerably worse long-termsurvival.13,14

This study considered veterans who underwentCABG in 1 of 44 VA medical centers in the USA.Rehospitalization rates included subsequent hospital-izations in all VA medical centers, but not non-VAhospitalizations. Our earlier comparison of veteransundergoing stenting and conventional coronary angio-plasty, which incorporated Medicare hospitalizationdata, indicated that about 2% of those aged �65 yearswere rehospitalized in non-VA facilities.15 It is pos-sible, but unlikely, that we underestimated the extentof rehospitalization in veterans undergoing CABG inVA medical centers. This study is also subject to thelimitations of administrative data in that key indicatorsof outcome such as left ventricular function, numberof diseased vessels, prior CABG, and surgical prioritywere not available. A distinct advantage of this study

was that it identified all veter-ans undergoing CABG in VAmedical centers.

In summary, previousstudies have indicated thatshort- and long-term out-comes may be worse for Afri-can-Americans undergoingCABG. In the present study,African-American and whiteveterans undergoing CABGin VA medical centers from1994 through 1999 had com-parable operative mortality,slightly worse long-term sur-vival, and equivalent rehospi-talization rates.

1. Ford ES, Cooper RS. Racial/ethnic differ-ences in health care utilization of cardiovascu-lar procedures: a review of the evidence.Health Serv Res 1995;30:237–252.2. Whittle J, Conigliaro J, Good CB, LofgrenRP. Racial differences in the use of invasivecardiovascular procedures in the Department ofVeterans Affairs medical system. N Engl J Med1993;329:621–627.3. Mirvis DM, Burns R, Gaschen L, Cloar FT,Graney M. Variations in utilization of cardiacprocedures in the Department of Veterans Af-

fairs health care system: effects of race. J Am Coll Cardiol 1994;74:1297–1304.4. Peterson ED, Wright SM, Daley J, Thibault GE. Racial variation in cardiacprocedure use and survival following acute myocardial infarction in the Depart-ment of Veterans Affairs. JAMA 1994;271:1175–1180.5. Ferguson JA, Tierney WM, Westmoreland GR, Mamlin LA, Segar DS, EckertGJ, Zhou XH, Martin DK, Weinberger M. Examination of racial differences inmanagement of cardiovascular disease. J Am Coll Cardiol 1997;30:1707–1713.6. Sedlis SP, Fisher VJ, Tice D, Esposito R, Madmon L, Steinberg EH. Racialdifferences in the performance of invasive cardiac procedures in a Department ofVeterans Affairs Medical Center. J Clin Epidemiol 1997;50:899–901.7. Peniston RL, Lu DY, Papademetriou V, Fletcher RD. Severity of coronaryartery disease in black and white male veterans and the likelihood ofrevascularization. Am Heart J 2000;139:840–847.8. Peterson ED, Shaw LK, DeLong ER, Pryor DB, Califf RM, Mark DB. Racialvariation in the use of coronary revascularization procedures. N Engl J Med1997;336:480–486.9. Deyo RA, Cherkin DC, Ciol MA. Adapting a clinical comorbidity index foruse with ICD-9-CM administrative databases. J Clin Epidemiol 1992;45:613–619.10. Dominitz JA, Maynard C, Boyko EJ. Assessment of vital status in Depart-ment of Veterans Affairs National Databases: comparison with state deathcertificates. Ann Epidemiol 2001;11:281–286.11. Maynard C, Wright SM, Every NR, Ritchie JL. Racial differences in out-comes of veterans undergoing percutaneous interventions. Am Heart J 2001;142:309–313.12. Bridges CR, Edwards FH, Peterson ED, Coombs LP. The effect of race oncoronary bypass operative mortality. J Am Coll Cardiol 2000;36:1870–1876.13. Gray RJ, Nessim S, Khan SS, Denton T, Matloff JM. Adverse 5-year outcomeafter coronary artery bypass surgery in blacks. Arch Intern Med 1996;156:769–773.14. Taylor HA, Mickel MC, Chaitman BR, Sopko G, Cutter GR, Rogers WJ.Long-term survival of African Americans in the Coronary Artery Surgery Study(CASS). J Am Coll Cardiol 1997;29:358–364.15. Maynard C, Wright SM, Every NR, Ritchie JL. Comparison of outcomes ofcoronary stenting vs conventional coronary angioplasty in the Department ofVeterans Affairs Medical Centers. Am J Cardiol 2001;87:1240–1245.

FIGURE 1. Cumulative survival in African-American and white veterans undergoing CABG.

BRIEF REPORTS 895