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Utilization of Drug-Eluting Stents in the Veterans Health Administration

Charles Maynard, PhDa,b,*, Elliott Lowy, PhDa, Teresa Wagner, MPHa, andAnne E. Sales, PhDa,b

Little is known about how drug-eluting stents (DESs) are used and perform ineveryday clinical practice. This report identifies factors associated with the use ofDESs in the Veterans Health Administration and compares mortality and the needfor coronary artery bypass graft surgery in patients who received DESs or bare metalstents. There was rapid adoption of DESs from the end of 2002 to September 2004,when 52% of percutaneous coronary interventions used DESs. Ten-day death rates inDES and bare metal stent groups were similar (0.8% vs 1.1%), as were 10-day bypasssurgery rates (0.2% vs 0.4%). In summary, in a large health care system, DESs wereused widely with low rates of death and bypass surgery. © 2005 Elsevier Inc. All

rights reserved. (Am J Cardiol 2005;96:218–220)

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oronary artery stents have been shown to be beneficial inandomized trials and everyday clinical practice.1 Despiteignificant decreases in mortality and the need for emer-ency coronary artery bypass graft surgery, restenosis afterercutaneous coronary intervention (PCI) continues to behe major event that is responsible for undesirable out-omes, including rehospitalization. Randomized trials and aeta-analysis of drug-eluting stents (DESs) suggest that

hese devices decrease angiographic restenosis and adverseardiac events compared with bare metal stents.2–4 How-ver, little is known about how DESs are used and performn everyday clinical practice.5 The purpose of this report isrst to identify factors associated with the use of DESs in

he Veterans Health Administration (VHA) and second toompare mortality and the need for emergency coronaryrtery bypass graft surgery in veterans who received DESsompared with those who received bare metal stents.

• • •his study included 17,266 PCIs performed in VHA med-

cal centers in fiscal years 2003 and 2004 (October 1, 2002o September 30, 2004). PCIs were identified by Interna-ional Classification of Diseases-Ninth Revision procedureodes 36.01, 36.02, 36.05, 36.06, or 36.07 and were ob-ained from the VHA inpatient medical files housed atustin, Texas. The procedure code for DESs, 36.07, was

nstituted in October 2002, when code 36.06, which previ-usly identified all coronary artery stents, became the codeor bare metal stents. DESs were approved for general usen April 2003. Procedures were defined as (1) DES (anyode 36.07), (2) bare metal stents (any code 36.06 only and

aDepartment of Veterans Affairs Puget Sound Healthcare System; andDepartment of Health Services, University of Washington, Seattle, Wash-ngton. Manuscript received January 7, 2005; revised manuscript receivednd accepted March 14, 2005.

This work was supported by a grant from the Department of Veteransffairs Quality Enhancement Research Initiative, Washington, DC.

* Corresponding author: Tel.: 206-277-6496; fax: 206-764-2935.

iE-mail address: cmaynard@u.washington.edu (C. Maynard).

002-9149/05/$ – see front matter © 2005 Elsevier Inc. All rights reserved.oi:10.1016/j.amjcard.2005.03.048

ot code 36.07), and (3) balloon only (codes 36.01, 36.02,r 36.05 only).

Age, gender, race, marital status, and institutional vol-me were obtained from the relevant Austin, Texas, files.ompensation pension status is an indicator of access toedical care, because those who have service- or nonser-

ice-connected disabilities have higher priority for care.o-morbid conditions were defined from Internationallassification of Diseases-Ninth Revision diagnosis codes;

hese included acute myocardial infarction (410.xx), unsta-le angina (411), diabetes mellitus (250.xx), and renal dis-ase (582.xx, 583.xx, 585, 586, 588.xx). Vital status, the usef coronary artery bypass graft surgery (procedure codes6.1x), and rehospitalization for myocardial infarction werelso collected.

Bivariate comparisons of predictor and outcome vari-bles with type of PCI were made with the chi-squaretatistic for categorical variables and the 2-sample t test forontinuous ones. Chi-square for trend statistic was used toest whether the decrease in the use of balloon angioplastyas statistically significant. We used logistic regression to

dentify predictors of DES use; because of the large sample,nly predictors with a p value �0.01 were selected. Theurpose of this analysis was to identify only predictors ofse and not to quantify with odds ratios the contribution ofach variable.

The proportion of procedures with DESs increased from1% in the first 6 months to 52% in the final 6 months of

he 2-year interval (Figure 1). Concomitantly, the propor-ion with bare metal stents decreased from �85% duringctober 2002 through March 2003 to 40% during April004 through September 2004. The decrease in cases withalloon angioplasty from only 14% to 7% was statisticallyignificant (p �0.0001). Patient characteristics with respecto PCI type were similar, which is noteworthy, becauseelatively large numbers made it easy to demonstrate statis-ical significance (Table 1). There was a statistically signif-

cant finding for race, mainly due to differences in unknown

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219Coronary Artery Disease/Utilization of Drug-Eluting Stents

tatus. A slightly larger proportion of the balloon-onlyroup had diabetes mellitus and/or unstable angina. A no-able finding concerned institutional volume and use ofESs; in centers that performed �200 cases per year (n �,116), 19% of procedures used DESs, whereas in centershat performed �200 cases per year (n � 15,150), 23% ofrocedures used DESs (p �0.0001).

igure. 1. Use of DESs (black bars), bare metal stents (gray bars), andalloon only (white bars) by 6-month intervals from October 2002 toeptember 2004.

able 1aseline demographic and clinical characteristics of veterans undergoing

haracteristic Device Type

DES(n � 3,946)

ge (yrs)�50 7%50–64 51%65–74 25%�75 17%ean age (yrs) 63 � 10en 98%aceWhite 65%African-American 8%Other 1%Unknown 26%arital status

Divorced 27%Married 57%Never married 6%Separated 4%Widowed 6%Unknown �1%ompensation pension statusService-connected disability 5%Nonservice-connected disability 35%No disability 59%Nonveteran 1%cute myocardial infarction* 31%nstable angina pectoris 34%iabetes mellitus 41%enal disease 4.4%

* Principal or primary diagnosis.

Stepwise logistic regression was used to identify predic-ors of DESs versus bare metal stents. In order of entry, theollowing factors were associated with use of DESs: (1)rocedure performed in the last half of fiscal year 2004, (2)edical center performed �100 cases per year, (3) race

ther than African-American, and (4) procedure was notssociated with a principal or primary diagnosis of acuteyocardial infarction. All 4 variables were highly statisti-

ally significant (p �0.0001) in this analysis of 15,438rocedures.

Mortality and use of coronary artery bypass graft surgery10 days after PCI were clearly increased for those who did

ot undergo stenting (Table 2). However, 10- (p � 0.14)nd 30-day (p � 0.07) death rates did not differ by stentype. Rates of coronary artery bypass graft surgery �10ays after the procedure were also similar in the 2 groups (p

0.34).

• • •he purpose of this report was to describe the use of DESs

n clinical practice in the VHA, 1 of the world’s largestntegrated health care organizations. Use of this new tech-ology increased rapidly from October 2002 to the end ofscal year 2004, when �50% of PCIs used DESs. These

neous coronary interventions (n � 17,334)

p Value

are Metal Stentn � 11,492)

Balloon Only(n � 1,828)

0.087% 7%

49% 47%25% 27%19% 18%4 � 10 64 � 10 0.3399% 99% 0.53

�0.000166% 67%10% 10%2% 2%

22% 21%0.030

26% 25%55% 56%7% 6%4% 4%7% 8%1% �1%

0.304% 4%

36% 36%59% 59%

1% 1%34% 33% 0.00136% 39% 0.00140% 44% 0.007

5.1% 5.6% 0.08

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220 The American Journal of Cardiology (www.AJConline.org)

esults can be compared with those of a recent report fromhe American College of Cardiology National Cardiac Dataegistry.5 In that study, the proportion of PCIs with DESs

ncreased from �20% immediately after approval in April003 to 45% in the final quarter of 2003. In the presenttudy, for the same interval, the rate of adoption was moreapid, from 2% to 24%, but not as extensive. Consistentith the National Cardiac Data Registry, our findings indi-

ated that small-volume centers were less likely to implantESs, which were also used less often in African-Ameri-

ans and in the setting of acute myocardial infarction.Findings with regard to 10- and 30-day death rates and to

0-day bypass surgical rates suggest that DESs performeds well as bare metal stents. Outcomes in the balloon-onlyroup were much worse, indicating that patients in thisroup were very different from those who received stents.ssuming that coding of these procedures was accurate,atients in the balloon-only group most likely had smalleressels with lesions that were not amenable to stenting.ecause of the decrease in the number of balloon-onlyrocedures, it is also possible that DESs were being used toreat smaller vessels that could not be treated with bareetal stents.The ability to identify predictors of use of DESs was

imited in part by the nature of administrative data. Proce-ures were identified by International Classification of Dis-ases-Ninth Revision procedure codes, and detailed proce-ure information, including type of lesion, whether theesion was successfully treated, and vessel size, was notvailable. Also, we were unable to assess the completenessnd accuracy of the coding of the procedure. Moreover, weould not determine the incidence of restenosis, althoughhe rate of rehospitalization for acute myocardial infarction0 days after a procedure in VHA medical centers was �1%

able 2utcomes of percutaneous coronary interventions

utcome Device Type

DES(n � 3,946)

eath �10 d after PCI 0.8%eath �30 d after PCI 1.3%ABG �10 d after PCI 0.2%

CABG � coronary artery bypass graft surgery.

or the 2 types of stents. However, VHA data are complete

nd timely, because information on mortality and hospital-zation is updated on a weekly basis.

In the VHA, adoption of this new medical technologyas very rapid because �50% of PCIs at the end of 2004sed DESs. These findings, similar to those from the Amer-can College of Cardiology National Cardiac Data Registry,uggest that a variety of hospital, patient, and clinical char-cteristics and general availability influenced the use ofESs and that the additional cost did not appear to limit

heir use. Concerns about lower use in African-Americansnd those who do not have health insurance are warranted,lthough veterans in the VHA have access to care, albeit atifferent priority levels. We could not determine whetherestenotic rates were better with DESs than with bare metaltents. However, in everyday clinical practice, key out-omes as measured by mortality and the need for coronaryrtery bypass surgery were very low and did not differ bytent type.

. Ritchie JL, Maynard C, Every NR, Chapko MK. Coronary artery stentoutcomes in a Medicare population: less emergency bypass surgery andlower mortality rates in patients with stents. Am Heart J 1999;138:437–440.

. Morice MC, Serruys PW, Sousa JE, Fajadet J, Hayashi EB, Perin M,Colombo A, Schuler G, Barragan P, Guagliumi G, et al. A randomizedcomparison of a sirolimus-eluting stent with a standard stent for coro-nary revascularization. N Engl J Med 2002;346:1773–1780.

. Moses JW, Leon MB, Popma JL, Fitzgerald PJ, Holmes DR,O’Shaughnessy C, Caputo RP, Kereiakes DJ, Williams DO, TeirsteinPS, et al. Sirolimus-eluting stents versus standard stents in patients withstenosis in a native coronary artery. N Engl J Med 2003;349:1315–1323.

. Babapulle MN, Joseph L, Belisle P, Brophy JM, Eisenberg MJ. Ahierarchical Bayesian meta-analysis of randomized clinical trials ofdrug-eluting stents. Lancet 2004;364:583–591.

. Rao SV, Shaw RE, Brindis RG, Klein LW, Peterson ED. Predictors ofdrug-eluting stent use in clinical practice: a report from the AmericanCollege of Cardiology National Cardiovascular Disease Registry (ACC-

p Value

Metal Stent11,492)

Balloon Only(n � 1,828)

2.1% �0.00012.7% 0.0013.1% �0.0001

Bare(n �

1.1%1.7%0.4%

NCDR). Circulation 2004;110:III-688.