cium score for progressive patients was 215%, asopposed to 28% for stable patients (p � 0.005). Anal-ysis of the area under the ROC curve (0.87) indicatedthat the diagnostic accuracy of EBCT for detectingpatients with angiographically defined progressionwas reasonable.

This was a small pilot study performed on highlyselected patients. The higher baseline score of theprogressive patients, which was not statically differentfrom that of the stable patients, may have an influenceon the calcium progression score. There were no re-gressive subjects, which means that the relation be-tween regression on angiography and changes in cor-onary calcium remains unclear.

In the present report, progressive patients hadincreases in calcium score when compared withstable patients. There seems to be an interestingassociation between the change in calcium scoreand angiographic changes; however, study of alarge, nonselected population is necessary for fur-ther clarification.

1. Wexler L, Brundage B, Crouse J, Detrano R, Fuster V, Maddahi J, RumbergerJ, Stanford W, White R, Taubert K. Coronary artery calcification: pathophysiol-ogy, epidemiology, imaging methods, and clinical implications. A statement forhealth professionals from the American Heart Association Writing Group. Cir-culation 1996;94:1175–1192.2. Rumberger JA, Sheedy PF II, Breen JF, Schwartz RS. Coronary calcium, asdetermined by electron beam computed tomography, and coronary disease onarteriogram. Effect of patient’s sex on diagnosis. Circulation 1995;91:1363–1367.3. Budoff MJ, Georgiou D, Brody A, Agatston AS, Kennedy J, Wolfkiel C,Stanford W, Shields P, Lewis RJ, Janowitz WR, Rich S, Brundage BH. Ultrafast

computed tomography as a diagnostic modality in the detection of coronary arterydisease: a multicenter study. Circulation 1996;93:898–904.4. Guerci AD, Spadaro LA, Goodman KJ, Lledo Perez A, Newstein D, Lerner G,Arad Y. Comparison of electron beam computed tomography scanning andconventional risk factor assessment for the prediction of angiographic coronaryartery disease. J Am Coll Cardiol 1998;32:673–679.5. Kaufmann RB, Sheedy PF III, Maher JE, Bielak LF, Breen JF, Schwartz RS,Peyser PA. Quantity of coronary artery calcium detected by electron beamcomputed tomography in asymptomatic subjects and angiographically studiedpatients. Mayo Clin Proc 1995;70:223–232.6. Agatston AS, Janowitz WR, Hildner FJ, Zusmer NR, Viamonte M Jr, DetranoR. Quantification of coronary artery calcium using ultrafast computed tomogra-phy. J Am Coll Cardiol 1990;15:827–832.7. Austen WG, Edwards JE, Frye RL, Gensini GG, Gott VL, Griffith LS,McGoon DC, Murphy ML, Roe BB. A reporting system on patients evaluated forcoronary artery disease. Report of the Ad Hoc Committee for Grading ofCoronary Artery Disease, Council on Cardiovascular Surgery, American HeartAssociation. Circulation 1975;51:5–40.8. Jukema JW, Bruschke AV, van Boven AJ, Reiber JH, Bal ET, ZwindermanAH, Jansen H, Boerma GJ, van Rappard FM, Lie KI, et al. Effects of lipidlowering by pravastatin on progression and regression of coronary artery diseasein symptomatic men with normal to moderately elevated serum cholesterol levels.The Regression Growth Evaluation Statin Study (REGRESS). Circulation 1995;91:2528–2540.9. Waters D, Higginson L, Gladstone P, Kimball B, Le May M, Boccuzzi SJ,Lesperance J. Effects of monotherapy with an HMG-CoA reductase inhibitor onthe progression of coronary atherosclerosis as assessed by serial quantitativearteriography. The Canadian Coronary Atherosclerosis Intervention Trial. Circu-lation 1994;89:959–968.10. Budoff MJ, Lane KL, Bakhsheshi H, Mao S, Grassmann BO, Friedman BC,Brundage BH. Rates of progression of coronary calcium by electron beamtomography. Am J Cardiol 2000;86:8–11.11. Maher JE, Bielak LF, Raz JA, Sheedy PF II, Schwartz RS, Peyser PA.Progression of coronary artery calcification: a pilot study. Mayo Clin Proc1999;74:347–355.12. Janowitz WR, Agatston AS, Viamonte M Jr. Comparison of serial quantita-tive evaluation of calcified coronary artery plaque by ultrafast computed tomog-raphy in persons with and without obstructive coronary artery disease. Am JCardiol 1991;68:1–6.13. Callister TQ, Cooil B, Raya SP, Lippolis NJ, Russo DJ, Raggi P. Coronaryartery disease: improved reproducibility of calcium scoring with an electron-beam CT volumetric method. Radiology 1998;208:807–814.14. Callister TQ, Raggi P, Cooil B, Lippolis NJ, Russo DJ. Effect of HMG-CoAreductase inhibitors on coronary artery disease as assessed by electron-beamcomputed tomography. N Engl J Med 1998;339:1972–1978.

Effect of Monitoring of Physician Performance onDoor-to-Balloon Time for Primary Angioplasty in Acute

Myocardial Infarction*

Eric A. Shry, MD, Robert E. Eckart, DO, Joshua B. Winslow, MD,William A. Rollefson, MD, and Daniel E. Simpson, MD

Primary angioplasty for ST-elevation acute myo-cardial infarction (AMI) is proven to have equiv-

alent or superior in-hospital and late outcomes com-pared with thrombolytic therapy.1,2 Any improvementin mortality compared with thrombolytic therapy maybe lost if “door-to-balloon” (the time from initialpatient arrival at the emergency department to first

angioplasty balloon inflation) times are �120 min-utes.3,4 The American College of Cardiology andAmerican Heart Association Guidelines for Manage-ment of Acute Myocardial Infarction recommend thatmean time be 90 � 30 minutes.”5 Previous studiesdemonstrated that alterations in prehospital, emer-gency department, and cardiology catheterization lab-oratory care can result in shorter times to treatment.6,7

However, there are currently no data on the effect thatpassive monitoring has on door-to-balloon times. Wesought to evaluate whether simply monitoring door-to-balloon times in a tertiary care medical centerwould alter physician behavior and decrease door-to-balloon time in the absence of any systematic changein emergency department management, cardiac cath-eterization laboratory activation, or primary angio-plasty performance.

From the Cardiology Service, Brooke Army Medical Center, SanAntonio, Texas. Dr. Shry’s address is: Cardiology Service MCHE-MDC, 3851 Roger Brooke Drive, Brooke Army Medical Center, SanAntonio, Texas 78234-6200. E-mail: Eric.Shry@amedd.army.mil.Manuscript received October 7, 2002; revised manuscript receivedand accepted December 13, 2002.

*The opinions and research contained herein are the private ones ofthe authors and are not to be considered as official or reflecting theviews of the Department of the Army or the Department of Defense.

867©2003 by Excerpta Medica, Inc. All rights reserved. 0002-9149/03/$–see front matterThe American Journal of Cardiology Vol. 91 April 1, 2003 doi:10.1016/S0002-9149(03)00022-5

• • •A retrospective review was conducted of the pa-

tients who presented with AMI to our institution fromJanuary 1998 to December 2000; this served as ourreference cohort (referred to subsequently as the “pre-monitoring” period). Subsequently, data were col-lected prospectively on all patients with AMI fromJanuary 2001 to February 2002 (“monitoring period”).Patients were excluded for purposes of analysis (ineither time period) if they presented with sudden car-diac death, received thrombolytic therapy, or werealready inpatients when they had their AMI. Through-out the study period, primary angioplasty was theprincipal therapy for AMI, with more than 95% ofpatients with AMI receiving primary angioplasty. Pa-tients in cardiogenic shock and/or cardiac arrest aftercatheterization laboratory activation were included inthe study.

Emergency department registration computer andcardiac catheterization laboratory computer clockswere synchronized in 1996. The emergency depart-

ment door arrival, first electrocardiogram, arterial ac-cess, and first balloon inflation were obtained from thecomputerized medical records stored in these comput-ers at the time of each event. Beginning January 1,2001, cardiology staff and fellows were informed thatdetailed data would be collected on delays to percu-taneous reperfusion therapy. At this time, all clocks inemergency department electrocardiography machines,physician pagers, and cardiovascular technician pag-ers were synchronized. During the monitoring period,the times of first electrocardiogram performance, car-diology consultation, and catheterization laboratoryactivation were similarly recorded. During the moni-toring period, there were no changes made in theprotocols for handling patients with an AMI, and thediagnostic and interventional cardiology staff re-mained stable.

The primary outcome was the comparison of meandoor-to-balloon times before and after the implemen-tation of routine monitoring. Secondary outcomes in-cluded analysis of times to events (e.g., time to firstelectrocardiogram, laboratory activation, arterial ac-cess, and so on) during the monitoring period, as wellas a comparison of daytime (6 A.M. to 4 P.M., Mondaythrough Friday, excluding federal holidays) versus“on-call” hours (any other hours). Continuous vari-ables are presented as mean � SD. Categoric vari-ables are presented as percentages. Mann-Whitneyrank sum tests were used to assess differences in timeintervals. Student’s t test was used to compare nor-mally distributed continuous variables. Differenceswere considered statistically significant if the p valuewas �0.05. Analysis was performed using Sigma Stat,version 2.03 (SPSS, Inc., Chicago, Illinois).

Of the 140 patients with AMI who underwentpercutaneous intervention during the study period,118 met entry criteria. There were 89 patients in thepremonitoring and 29 patients in the monitoring co-horts. Sixteen patients were excluded because of anin-hospital AMI, and 6 patients were excluded be-cause of sudden death before the diagnosis of AMI.Demographic characteristics are listed in Table 1.Patient characteristics were similar during the 2 peri-ods. Procedural success and Thrombolysis In Myocar-dial Infarction grade 3 flow rates were �90% duringthe 2 periods.

Door-to-balloon time results are listed in Table 2.Mean door-to-balloon time decreased from 133 min-utes before monitoring to 99 minutes during the mon-itoring period (p � 0.002). The percentage of subjectswho had a door-to-balloon time �120 minutes in-creased from 48% to 79% with monitoring (p �0.006). Subjects who presented to the emergency de-partment during on-call hours had a 24-minute delayto reperfusion compared with those who presentedduring daytime hours (p � 0.004).

Time delays during the monitoring period are listedin Table 3 and are categorized according to daytimeand on-call presentation times to the emergency de-partment. The longest delays during daytime and on-call hours were the time from catheterization labora-tory activation to patient entry into the laboratory and

TABLE 1 Patient Characteristics*

PremonitoringPeriod

MonitoringPeriod

(n � 89) (n � 29)

Age (yrs) 62 � 12 64 � 11Diabetes 36% 31%Hypertension 69% 86%Hyperlipidemia 53% 62%Previous MI 18% 21%Previous coronary bypass

surgery14% 13%

Ejection fraction 0.49 � 0.15 0.48 � 0.13Cardiogenic shock 9% 13%

*p � NS for all values.

TABLE 2 Effect of Monitoring on Door-to-Balloon Time(minutes)

PremonitoringPeriod

MonitoringPeriod p Value

All subjects(n � 118)

133 99 0.001

Daytime presentation(n � 41)

110 86 0.130

On-call presentation(n � 77)

141 108 0.007

TABLE 3 Interval Times as a Function of PresentationTime (minutes)

Daytime On-call

Door to electrocardiogram 9 6Electrocardiogram to cardiology consultation 15 8Consultation to laboratory activation 7 12Laboratory activation to laboratory arrival 26 49*Laboratory arrival to arterial access 7 8Arterial access to first balloon 22 25

*p � 0.01.Times in this table were obtained during the monitoring period only.

868 THE AMERICAN JOURNAL OF CARDIOLOGY� VOL. 91 APRIL 1, 2003

arterial access to balloon inflation. Prolonged on-calldoor-to-balloon times were due to delays in catheter-ization laboratory activation (daytime 26 minutes, on-call 49 minutes; p � 0.01).

• • •Passive monitoring of door to first balloon inflation

time in AMI resulted in a significant decrease indoor-to-balloon times at our institution, and it almostdoubled the proportion of patients who met publishedguidelines. This was in the absence of changing pre-hospital protocols, emergency department processing,cardiology consultation procedures, catheterizationlaboratory protocols, or a significant change in staff-ing. Despite understanding the importance of door-to-balloon time, our physicians’ response appeared to besignificantly affected by having to report their times.Although the effect of monitoring has been describedin other areas of cardiovascular medicine,8 we did notanticipate such a dramatic impact on an emergencyprocedure. Because reporting outcomes such as mor-tality can be biased based on patient selection,9 pro-cess measures that have direct impact on patient out-comes such as door-to-balloon times are often bettersuited to assess quality of care. Our report suggeststhat the reporting of process measures also has thepotential to improve outcomes by impacting physicianbehavior.

In a recent study,7 electrocardiographs were in-stalled on all ambulances, dedicated personnel werehired, a dedicated paging system was installed, andemergency department physicians began activatingthe “cath team” without initial cardiology consulta-tion. This decreased mean door-to-balloon time from124 to 86 minutes. Similarly, a second recent investi-gation6 found a program of active monitoring andchanges in treatment protocols could decrease treat-ment delays. These investigations did not attempt toseparate the effect of monitoring from the effect ofaltering treatment protocols. We found a similar ben-efit in door-to-balloon times by simply monitoring.

Although some efforts were made to lower times inthe emergency department, most delays at our institu-tion were under the control of the cardiology section.The time from arterial access to balloon inflation (24minutes) was similar to other reports.6 The delay forcatheterization laboratory activation was significant,even during hours the catheterization laboratory staff

were in the hospital. Our on-call delay (23 minutes)was reflective of travel time to the hospital.

Our data may be affected by the presence of train-ing programs in cardiology and emergency medicineat our facility. Fellows’ performance may be affectedby having to report times to their staff physicians.Additionally, our report was underpowered to detect adifference in daytime event times due to the smallnumber of patients who presented during the day inthe monitoring period (n � 11).

In a series of 118 patients with AMI who un-derwent primary angioplasty, the effect of moni-toring was evaluated without any change in themanagement of patients with AMI during this pe-riod. Monitoring resulted in a decrease in overallmean door-to-balloon time (daytime and on-calltimes) and an increase in the proportion of patientswho underwent their first balloon inflation in <120minutes.

1. Grines CL, Browne KF, Marco J, Rothbaum D, Stone GW, O’Keefe J, OverlieP, Donohue B, Chelliah N, Timmis GC. A comparison of immediate angioplastywith thrombolytic therapy for acute myocardial infarction. (PAMI-1). N EnglJ Med 1993;328:673–679.2. Zijlstra F, de Boer MJ, Hoorntje JC, Reiffers S, Reiber JH. A comparison ofimmediate coronary angioplasty with intravenous streptokinase in acute myocar-dial infarction. N Engl J Med 1993;328:680–684.3. The Global Use of Strategies to Open Occluded Coronary Arteries in AcuteCoronary Syndromes (GUSTO-IIb) Angioplasty Substudy Investigators. A clin-ical trial comparing primary coronary angioplasty with tissue plasminogen acti-vator for acute myocardial infarction. N Engl J Med 1997;336:1621–1628.4. Cannon CP, Gibson CM, Lambrew CT, Shoultz DA, Levy D, French WJ, GoreJM, Weaver WD, Rogers WJ, Tiefenbrunn AJ. Relationship of symptom-onset-to-balloon time and door-to-balloon time with mortality in patients undergoingangioplasty for acute myocardial infarction. JAMA 2000;283:2941–2947.5. Ryan TJ, Antman EM, Brooks NH, Califf RM, Hillis LD, Hiratzka LF,Rapaport E, Riegel B, Russell RO, Smith EE III, et al. ACC/AHA guidelines forthe management of patients with acute myocardial infarction: 1999 update: areport of the American College of Cardiology/American Heart Association TaskForce on Practice Guidelines (Committee on Management of Acute MyocardialInfarction). J Am Coll Cardiol 1999;34:890–911.6. Ward MR, Lo ST, Herity NA, Lee DP, Yeung AC. Effect of audit ondoor-to-inflation times in primary angioplasty/stenting for acute myocardial in-farction. Am J Cardiol 2001;87:336–339.7. Chang MW, Salyer C, Allen S, Whitaker J, Jordan C, Hunter J, Wiseman R,Washington G, Bass T. Reductions in door-to-balloon times and overall mortalityin ST-segment elevation acute myocardial infarction using NRMI outcomes datato direct process improvement in a community-based tertiary referral center(abstr). Circulation 2001;104(suppl II):II-631.8. Hannan EL, Kilburn H Jr, Racz M, Shields E, Chassin MR. Improving theoutcomes of coronary artery bypass surgery in New York State. JAMA 1994;271:761–766.9. Chassin MR, Hannan EL, DeBuono BA. Benefits and hazards of reportingmedical outcomes publicly. N Engl J Med 1996;334:394–398.

BRIEF REPORTS 869