requirement for emergent coronary artery bypass surgery following percutaneous coronary intervention...

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Requirement for Emergent Coronary Artery Bypass Surgery Following Percutaneous Coronary Intervention in the Stent Era Probal Roy, MD, Axel de Labriolle, MD, Nicholas Hanna, MD, Laurent Bonello, MD, Teruo Okabe, MD, Tina L. Pinto Slottow, MD, Daniel H. Steinberg, MD, Rebecca Torguson, MPH, Kimberly Kaneshige, BS, Zhenyi Xue, MS, Lowell F. Satler, MD, Kenneth M. Kent, MD, PhD, William O. Suddath, MD, Augusto D. Pichard, MD, Joseph Lindsay, MD, and Ron Waksman, MD* Performance of percutaneous coronary intervention (PCI) at centers without cardiotho- racic surgery is a contentious issue. Although this practice allows greater access to care, there are safety concerns. The aim was to assess the requirement for emergent coronary artery bypass grafting (CABG) after PCI and characterize patients at highest risk using independent predictors. The study population consisted of 21,957 unselected patients who underwent PCI from August 1994 (Food and Drug Administration stent approval) to January 2008 at a single medical center. Patients requiring emergent CABG (defined as within 24 hours of the index procedure) were identified. Logistic regression analysis was performed to assess for independent correlates of emergent CABG. Emergent CABG was required in 90 patients (cumulative incidence 0.41%). Indications for CABG included triple-vessel disease, dissection, acute closure, perforation, and failure to cross. These patients had significantly higher in-hospital cardiac death rates (7.8% vs 0.7%; p <0.01) and higher rates of Q-wave myocardial infarction, neurologic events, and renal insuffi- ciency. Independent correlates of emergent CABG after PCI were acute ST-segment elevation myocardial infarction presentation, cardiogenic shock, triple-vessel disease, and type C lesion. Risk assessment based on these predictors identified 0.3% of the patient population to have a 9.3% cumulative incidence of emergent CABG. In conclusion, the need for emergent CABG after PCI in the stent era was low and was associated with poor in-hospital outcomes. Risk was nonuniform, with 0.3% of the study population, charac- terized by acute presentation and complex coronary disease, at heightened risk of emergent surgery. © 2009 Elsevier Inc. All rights reserved. (Am J Cardiol 2009;103:950 –953) In real-world practice, percutaneous coronary interven- tion (PCI) is performed commonly at sites without cardio- thoracic surgical backup worldwide. Primary PCI has been well established to be superior to fibrinolytic therapy in the setting of acute myocardial infarction (MI). 1 PCI in nonsur- gical centers allows greater access for patients presenting with acute MI 2 to what is now the standard of care. To attain adequate proficiency, nonsurgical centers also need to per- form elective PCI. Given that the issue of PCI at nonsurgical centers is unresolved, we aimed to report the risk, outcomes, and correlates of emergent coronary artery bypass grafting (CABG) from a large referral medical center with on-site cardiothoracic surgery. Furthermore, the study aimed to risk-stratify patients to characterize the subset with height- ened risk of emergent surgery. Methods This was a single-center observational study. The study population consisted of 21,957 unselected patients who un- derwent PCI at Washington Hospital Center, Washington, DC, from August 1994 (Food and Drug Administration stent approval) to January 2008. These patients were entered into a prospective registry and subsequently followed up for clinical events. There were no specific exclusion criteria in the study. Patients who required emergent CABG were identified, and appropriate source documentation was re- viewed. All patients gave written consent for the procedure, and the study was conducted with local institutional review board approval. PCI was performed using a standard technique through the femoral approach in most cases. All patients were treated with the contemporary standard-of-care antiplatelet drug regimen unless contraindicated. Dual-antiplatelet ther- apy was recommended for a minimum of 4 weeks for patients treated with bare-metal stents and 6 months for those who received drug-eluting stents. During PCI, patients underwent systemic anticoagulation using either bivalirudin (0.75-mg/kg bolus followed by 1.75-mg/kg/hour intrave- nous infusion) or unfractionated heparin (40-U/kg bolus and additional heparin to achieve an activated clotting time of 250 to 300 seconds). Only in-hospital outcomes were assessed in the study. Emergent CABG was defined as coronary artery surgical revascularization within 24 hours of the index PCI proce- dure. Cardiac death was defined as all deaths for which a noncardiac cause could not be shown. Q-Wave MI was Division of Cardiology, Washington Hospital Center, Washington, DC. Manuscript received August 28, 2008; revised manuscript received and accepted December 1, 2008. *Corresponding author: Tel: 202-877-2812; Fax: 202-877-2715. E-mail address: [email protected] (R. Waksman). 0002-9149/09/$ – see front matter © 2009 Elsevier Inc. All rights reserved. www.AJConline.org doi:10.1016/j.amjcard.2008.12.025

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Page 1: Requirement for Emergent Coronary Artery Bypass Surgery Following Percutaneous Coronary Intervention in the Stent Era

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Requirement for Emergent Coronary Artery Bypass SurgeryFollowing Percutaneous Coronary Intervention in the Stent Era

Probal Roy, MD, Axel de Labriolle, MD, Nicholas Hanna, MD, Laurent Bonello, MD,Teruo Okabe, MD, Tina L. Pinto Slottow, MD, Daniel H. Steinberg, MD, Rebecca Torguson, MPH,

Kimberly Kaneshige, BS, Zhenyi Xue, MS, Lowell F. Satler, MD, Kenneth M. Kent, MD, PhD,William O. Suddath, MD, Augusto D. Pichard, MD, Joseph Lindsay, MD, and Ron Waksman, MD*

Performance of percutaneous coronary intervention (PCI) at centers without cardiotho-racic surgery is a contentious issue. Although this practice allows greater access to care,there are safety concerns. The aim was to assess the requirement for emergent coronaryartery bypass grafting (CABG) after PCI and characterize patients at highest risk usingindependent predictors. The study population consisted of 21,957 unselected patients whounderwent PCI from August 1994 (Food and Drug Administration stent approval) toJanuary 2008 at a single medical center. Patients requiring emergent CABG (defined aswithin 24 hours of the index procedure) were identified. Logistic regression analysis wasperformed to assess for independent correlates of emergent CABG. Emergent CABG wasrequired in 90 patients (cumulative incidence 0.41%). Indications for CABG includedtriple-vessel disease, dissection, acute closure, perforation, and failure to cross. Thesepatients had significantly higher in-hospital cardiac death rates (7.8% vs 0.7%; p <0.01)and higher rates of Q-wave myocardial infarction, neurologic events, and renal insuffi-ciency. Independent correlates of emergent CABG after PCI were acute ST-segmentelevation myocardial infarction presentation, cardiogenic shock, triple-vessel disease, andtype C lesion. Risk assessment based on these predictors identified 0.3% of the patientpopulation to have a 9.3% cumulative incidence of emergent CABG. In conclusion, theneed for emergent CABG after PCI in the stent era was low and was associated with poorin-hospital outcomes. Risk was nonuniform, with 0.3% of the study population, charac-terized by acute presentation and complex coronary disease, at heightened risk of emergent

surgery. © 2009 Elsevier Inc. All rights reserved. (Am J Cardiol 2009;103:950–953)

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In real-world practice, percutaneous coronary interven-ion (PCI) is performed commonly at sites without cardio-horacic surgical backup worldwide. Primary PCI has beenell established to be superior to fibrinolytic therapy in the

etting of acute myocardial infarction (MI).1 PCI in nonsur-ical centers allows greater access for patients presentingith acute MI2 to what is now the standard of care. To attain

dequate proficiency, nonsurgical centers also need to per-orm elective PCI. Given that the issue of PCI at nonsurgicalenters is unresolved, we aimed to report the risk, outcomes,nd correlates of emergent coronary artery bypass graftingCABG) from a large referral medical center with on-siteardiothoracic surgery. Furthermore, the study aimed toisk-stratify patients to characterize the subset with height-ned risk of emergent surgery.

ethods

This was a single-center observational study. The studyopulation consisted of 21,957 unselected patients who un-erwent PCI at Washington Hospital Center, Washington,

Division of Cardiology, Washington Hospital Center, Washington, DC.anuscript received August 28, 2008; revised manuscript received and

ccepted December 1, 2008.*Corresponding author: Tel: 202-877-2812; Fax: 202-877-2715.

nE-mail address: [email protected] (R. Waksman).

002-9149/09/$ – see front matter © 2009 Elsevier Inc. All rights reserved.oi:10.1016/j.amjcard.2008.12.025

C, from August 1994 (Food and Drug Administrationtent approval) to January 2008. These patients were enterednto a prospective registry and subsequently followed up forlinical events. There were no specific exclusion criteria inhe study. Patients who required emergent CABG weredentified, and appropriate source documentation was re-iewed. All patients gave written consent for the procedure,nd the study was conducted with local institutional reviewoard approval.

PCI was performed using a standard technique throughhe femoral approach in most cases. All patients werereated with the contemporary standard-of-care antiplateletrug regimen unless contraindicated. Dual-antiplatelet ther-py was recommended for a minimum of 4 weeks foratients treated with bare-metal stents and 6 months forhose who received drug-eluting stents. During PCI, patientsnderwent systemic anticoagulation using either bivalirudin0.75-mg/kg bolus followed by 1.75-mg/kg/hour intrave-ous infusion) or unfractionated heparin (40-U/kg bolus anddditional heparin to achieve an activated clotting time of50 to 300 seconds).

Only in-hospital outcomes were assessed in the study.mergent CABG was defined as coronary artery surgical

evascularization within 24 hours of the index PCI proce-ure. Cardiac death was defined as all deaths for which a

oncardiac cause could not be shown. Q-Wave MI was

www.AJConline.org

Page 2: Requirement for Emergent Coronary Artery Bypass Surgery Following Percutaneous Coronary Intervention in the Stent Era

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951Coronary Artery Disease/Emergent CABG After PCI

efined as an increase in creatine kinase-MB �2 times thepper normal value (2.6 ng/ml) in the presence of new Qaves on the electrocardiogram in �2 contiguous leads.

n-hospital renal insufficiency was defined as �50% in-rease from baseline serum creatinine during hospitalizationor the index procedure. Neurologic events were a compos-te of cerebrovascular accidents and transient ischemic at-acks. Cerebrovascular accident was defined as a neurologicnsult severe enough to leave a persistent deficit. Transientschemic attack was defined as loss of neurologic functionaused by ischemia, abrupt in onset, persisting for �24ours, and clearing without residual signs.

Demographic, clinical, and procedural data and in-hos-ital outcomes were collected. These data were obtainedsing hospital chart review by independent research person-el blinded to the study objectives. All data managementnd analyses were performed by a dedicated data coordi-ating center (Data Center, Cardiovascular Research Insti-ute, Washington, DC). A committee independently adjudi-ated all subsequent clinical events.

Statistical analysis was performed using SAS, version.1 (SAS Institute, Cary, North Carolina). Continuous vari-bles were expressed as mean � SD and compared usingtudent’s t test. Categorical variables were expressed asercentage and compared using either chi-square test orisher’s exact test. A p value �0.05 was considered to

ndicate statistical significance. Predictors of emergentABG were sought using logistic regression analysis. Vari-

able 1aseline Clinical Characteristics

ariable CABG

Yes(n � 90)

No(n � 21,867)

p Value

en 63 (70.0%) 14,621 (67.0%) 0.5ge (yrs) 64.7 � 10.2 64.0 � 40.8 0.5iabetes mellitus 34 (37.8%) 7,030 (32.5%) 0.3

nsulin-requiring diabetes 11 (12.2%) 2,305 (10.7%) 0.6urrent smoker 20 (22.2%) 4,489 (20.5%) 0.7ystemic hypertension 71 (78.9%) 16,488 (75.9%) 0.5yslipidemia* 72 (80.0%) 17,396 (80.5%) 0.9amilial history 53 (60.2%) 12,019 (57.1%) 0.6hronic renal insufficiency 6 (6.7%) 2,546 (11.8%) 0.1revious MI 49 (56.3%) 8,831 (42.9%) 0.01revious CABG 8 (8.9%) 5,464 (25.2%) �0.001revious PCI 26 (29.9%) 5,739 (27.5%) 0.6eripheral vascular disease 20 (22.7%) 3,572 (16.6%) 0.1resentationStable angina pectoris 10 (11.1%) 5,171 (23.8%) 0.005Unstable angina pectoris 47 (52.2%) 11,546 (53.2%) 0.9Acute MI 26 (28.9%) 2,466 (11.4%) �0.001Cardiogenic shock 26 (28.9%) 765 (3.5%) �0.001No. of diseased vessels 2.5 � 0.7 2.0 � 0.9 �0.001Left ventricular ejection

fraction (%)45 � 14 47 � 14 0.3

Values expressed as number (percent) or mean � SD.* Includes patients with a previously documented diagnosis of dyslipi-

emia. The patient may be treated with diet or medication. A new diagnosisan be made during this hospitalization for increased total cholesterol160 mg/dl. It does not include increased triglycerides.

bles entered into the model were history of acute MI, d

T-segment elevation MI presentation, cardiogenic shock,-vessel disease, and American College of Cardiology/merican Heart Association type C lesion classification.nivariate predictors with p �0.1 were entered into theultivariate analysis. Odds ratios (ORs) and 95% confi-

ence intervals (CIs) were reported. Patients were stratifiedccording to the number of predictors, and risk in eachroup was reported.

esults

In the overall study population, 90 patients (cumulativencidence 0.41%) required emergent CABG. Baseline clin-cal, angiographic, and procedural characteristics are listedn Tables 1 and 2. There were a number of baseline differ-nces between groups. Patients who required emergentABG were more likely to have had a previous MI and lessrevious CABG surgery. These patients presented less withtable angina and more with acute ST-segment elevation MInd cardiogenic shock. In addition, patients who requiredmergent CABG had a higher frequency of 3-vessel diseasend American College of Cardiology/American Heart As-ociation classification type C lesions. Patients in the CABGroup had more intra-aortic balloon pump use and proce-

able 2aseline angiographic and procedural characteristics

ariable CABG

Yes(n � 181)

No(n � 39,633)

p Value

arget vesselLeft main 5 (2.8%) 847 (2.1%) 0.4Left anterior descending 63 (34.8%) 13,667 (34.5%) 0.9Left circumflex 44 (24.3%) 9,345 (23.6%) 0.8Right 64 (35.4%) 12,180 (30.7%) 0.2Saphenous vein graft 5 (2.8%) 3,218 (8.1%) 0.008esion locationOstial 13 (7.2%) 2,493 (6.7%) 0.8Proximal 72 (40.0%) 15,182 (40.9%) 0.8Mid 63 (35.0%) 13,661 (36.8%) 0.6Distal 32 (17.8%) 5,270 (14.2%) 0.2esion type (ACC/AHA

classification)A 19 (11.1%) 3,199 (8.7%) 0.3B 77 (45.0%) 23,949 (65.2%) �0.001C 75 (43.9%) 9,580 (26.1%) �0.001In-stent restenosis 17 (8.9%) 2,942 (7.4%) 0.5rocedural detailsNo. of lesions treated* 2.1 � 1.3 1.8 � 1.6 0.09Cutting balloon 1 (1.1%) 1249 (5.0%) 0.1Intra-aortic balloon

pump*38 (42.2%) 1179 (5.5%) �0.001

Glycoprotein IIb/IIIainhibitor use*

10 (11.1%) 3355 (15.9%) 0.2

Dissection 32 (17.2%) 721 (1.9%) �0.001Abrupt closure 17 (9.1%) 202 (0.5%) �0.001No reflow 8 (4.3%) 208 (0.6%) �0.001

Values expressed as number (percent) or mean � SD.* Patient-based variable.ACC/AHA � American College of Cardiology/American Heart Asso-

iation.

ural complications (dissection and abrupt closure).

Page 3: Requirement for Emergent Coronary Artery Bypass Surgery Following Percutaneous Coronary Intervention in the Stent Era

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

In-hospital outcomes are shown in Figure 1. Rates forardiac death (7.8% vs 0.7%; p �0.01), Q-wave MI5.7% vs 0.4%; p �0.01), neurologic events (10% vs.9%; p �0.01), and renal insufficiency (25.6% vs 4.6%;�0.01) were significantly higher in patients who re-

uired emergent CABG. Indications for emergent CABGre shown in Figure 2.

Predictors of emergent CABG using logistic regressionnalysis are listed in Table 3. Univariate predictors wererevious MI, acute ST-segment elevation MI presentation,ardiogenic shock, 3-vessel disease, and type C lesion.hese univariate predictors, except for previous MI, were

ndependent correlates of emergent CABG using multivar-ate analysis. Distribution of the study population by theumber of predictors per patient is shown in Figure 3. Mostatients (87.8%) had either 0 or 1 of the identified indepen-

igure 1. In-hospital outcomes in patients who required emergent CABG.nsuff � insufficiency; neuro � neurologic.

Figure 2. Distribution of indications for emergent CABG.

able 3redictive factors of emergent coronary artery bypass grafting using

ogistic regression analysis

Univariate Analysis Multivariate Analysis

OR 95%CI

p Value OR 95%CI

p Value

revious acute MI 1.7 1.1–2.6 0.01 1.5 0.8–3.0 0.2cute MI 3.2 2.0–5.0 �0.001 2.7 1.4–5.3 0.003ardiogenic shock 11.4 6.2–20.9 �0.001 4.8 2.3–9.7 �0.001-Vessel disease 2.3 1.8–3.0 �0.001 1.7 1.2–2.4 0.004ype C lesion 2.6 1.7–4.0 �0.001 2.8 1.5–5.2 0.001

ent predictors. Conversely, only 2.1% of the study popu- i

ation had either 3 or 4 of the predictors identified usingultivariate analysis, and 0.3% had all 4 predictors. The

umulative incidence of emergent CABG in patient sub-roups characterized by the number of predictors per patients shown in Figure 4. An incremental increase in risk ofmergent CABG was seen with an increased number ofredictors per patient. Heightened risk (cumulative inci-ence 9.3%) was seen in patients who had all 4 predictors.onversely, the rest of the patient population had a cumu-

ative incidence of emergent surgery of 0.3%.

iscussion

The present study assessed the risk, outcomes, and cor-elates of emergent CABG after PCI in a large referraledical center with on-site cardiothoracic surgery after

tent approval by the US Food and Drug Administration inugust 1994. The requirement for emergent CABG afterCI continues to be a relevant issue in interventional car-iology, and performance of PCI in centers without cardio-horacic surgery is still debated. In keeping with previouseports, emergent CABG after PCI was both infrequent andssociated with a worse short-term prognosis. In the presenttudy, we reported 4 independent predictors of emergentABG and characterized patients at highest risk. Theseatients presented with emergent indications for revascular-

Figure 3. Distribution of patient population by number of predictors.

igure 4. Cumulative incidence of emergent CABG according to number ofredictors per patient.

zation coupled with anatomically complex disease. Al-

Page 4: Requirement for Emergent Coronary Artery Bypass Surgery Following Percutaneous Coronary Intervention in the Stent Era

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953Coronary Artery Disease/Emergent CABG After PCI

hough inferences about the performance of PCI at nonsur-ical centers cannot be made, the study findings emphasizedhe role of emergent CABG after PCI and which patientsere at highest risk.The requirement for emergent CABG after PCI in the

resent study was infrequent (0.41%). In a report from theayo Clinic of 23,087 patients, incidences of emergencyABG in the “initial stent era” and “current stent era” were.7% and 0.3%, respectively. As anticipated, a significantecrease was reported from the “pre-stent era” (2.9%).3

imilarly, a more than 10-fold decrease in need for emer-ent CABG was reported from the Cleveland Clinic data-ase (1.5% vs 0.14%) from 1992 to 2000 studying 18,593CI procedures.4 The risk of emergent CABG in the presenteport, restricted to patients undergoing PCI in the stent era,as in keeping with these reports from similar-sized popu-

ations. Whether the risk of emergent CABG after PCIeported from these centers with greater operator and sup-ort staff experience were generalizable to nonsurgical cen-ers was a matter of contention. Recently, the largest com-arison of outcomes of patients undergoing PCI at surgicalersus nonsurgical centers showed no major difference inhe need for emergency CABG after PCI.5

An association between emergent CABG and increasedn-hospital mortality has been observed. In-hospital all-ause mortality rates of 10% to 15% were seen in theentioned published reports.3,4 In the present study, emer-

ent CABG was associated not only with increased cardiaceath and Q-wave MI, but also with neurologic events andenal insufficiency. The strong associations with renal in-ufficiency and neurologic events may have also impactedn longer term prognosis in patients who survived the indexospital admission. The poor outcome in patients whoeeded emergent CABG was a sobering reminder that irre-pective of the availability of cardiothoracic services on site,utcomes in this cohort of patients was poor.

In this analysis, independent predictors for emergentABG after PCI were acute MI presentation, cardiogenic

hock, 3-vessel disease, and type C lesion. A worse Amer-can College of Cardiology/American Heart Associationesion score has been the most consistent predictor formergent CABG after PCI.3,4 Long diseased segments,eavily calcified lesions, and tortuous vessels were morerone to procedural failure. Hence, it was consistent thatreatment of type C lesions was a strong predictor formergent surgery. The present report identified acute pre-entations of both acute MI and cardiogenic shock to beredictive of emergency CABG. Yang et al3 previouslydentified emergent PCI as a predictor of emergency CABGn the stent era (OR 3.77, 95% CI 2.02 to 7.02). Multivesselisease was also reported to be a predictor in this analysis

OR 2.40, 95% CI 1.44 to 4.0), as in the present study. The

ndings suggested that the risk of requiring emergent CABGas nonuniform, with patients who presented acutely with

omplex disease most prone. The acute presentation of thisroup meant they were best managed using immediate PCI andere high-risk surgical candidates. These findings may further

ontribute to the discussion of the performance of PCI atonsurgical centers. It is anticipated that the mortality benefitesulting from the availability of local PCI will more thanffset any increase in mortality that maybe associated with aack of on-site CABG.

The debate regarding the performance of PCI at centersithout cardiothoracic surgery is unresolved. A report fromennberg et al6 compared outcomes of patients who un-

erwent PCI in 1,121 hospitals with and without CABG.his study showed a higher mortality rate in patients whonderwent nonprimary/rescue PCI at centers withoutABG.6 Conversely, a number of published reports eitherompared the outcomes of PCI at centers with and withoutABG surgery or reported the outcomes from non-CABG

urgical centers as being in favor of PCI without surgicalackup. The most recent comparison, the largest to date study-ng this issue, supported the practice of PCI at nonsurgicalenters.5 It was important to note that reports suggesting thisractice was feasible also stated that it was imperative that theonsurgical center be adequately equipped to perform PCI.

This was a single-center observational study with theimitations inherent to this type of analysis. The definition ofmergent CABG, surgery required within 24 hours of PCI,ay have been overinclusive. Clinical outcome was limited

o in-hospital events. Correlates of emergent CABG wereot weighted when contribution to risk was assessed.

. Keeley EC, Boura JA, Grines CL. Primary angioplasty versus intrave-nous thrombolytic therapy for acute myocardial infarction: a quantita-tive review of 23 randomised trials. Lancet 2003;361:13–20.

. Peels HO, de Swart H, Ploeg TV, Hautvast RW, Cornel JH, Arnold AE,Wharton TP, Umans VA. Percutaneous coronary intervention withoff-site cardiac surgery backup for acute myocardial infarction as astrategy to reduce door-to-balloon time. Am J Cardiol 2007;100:1353–1358.

. Yang EH, Gumina RJ, Lennon RJ, Holmes DR Jr., Rihal CS, Singh M.Emergency coronary artery bypass surgery for percutaneous coronaryinterventions: changes in the incidence, clinical characteristics, andindications from 1979 to 2003. J Am Coll Cardiol 2005;46:2004–2009.

. Seshadri N, Whitlow PL, Acharya N, Houghtaling P, Blackstone EH,Ellis SG. Emergency coronary artery bypass surgery in the contempo-rary percutaneous coronary intervention era. Circulation 2002;106:2346–2350.

. Kutcher MA. Percutaneous Coronary Interventions at Facilities WithoutOn-Site Cardiac Surgery (National Cardiovascular Data Registry). ACC2008.

. Wennberg DE, Lucas FL, Siewers AE, Kellett MA, Malenka DJ. Out-comes of percutaneous coronary interventions performed at centerswithout and with onsite coronary artery bypass graft surgery. JAMA

2004;292:1961–1968.