(Circulation. 1997;95:2479.)
© 1997 American Heart Association, Inc.
Articles |
Relation of Operator Volume and Experience to Procedural Outcome of Percutaneous Coronary Revascularization at Hospitals With High Interventional Volumes
From the Cleveland Clinic Foundation, Cleveland, Ohio (S.G.E.); Emory University, Atlanta, Ga (W.W., S.B.K.); Mayo Clinic, Rochester, Minn (D.H.); San Francisco Heart Institute, Daly City, Calif (R.S.); and St Vincent Heart Institute, Portland, Ore (P.C.B.).
Correspondence to Stephen G. Ellis, MD, The Cleveland Clinic Foundation, 9500 Euclid Ave, F-25, Cleveland, OH 44195. E-mail elliss{at}cesmtp.ccf.org
Abstract
Background Although an inverse relation between physician
caseload and complications has been conclusively demonstrated for
several surgical procedures, such data are lacking for
percutaneous coronary intervention, and the
ACC/AHA guidelines requiring 
75 cases per year for operator
"competency" are considered by some physicians to be
arbitrary.
Methods and Results From quality-controlled databases at
five high-volume centers, models predictive of death and the composite
outcome of death, Q-wave infarction, or emergency bypass surgery were
developed from 12 985 consecutively treated patients during 1993
through 1994. Models had moderate to high discriminative capacity (area
under ROC curves, 0.65 to 0.85), were well calibrated, and were not
overfitted by standard tests. These models were used for risk
adjustment, and the relations between both yearly caseload and years of
interventional experience and the two adverse outcome measures were
explored for all 38 physicians with 30 cases per year. The average
physician performed a mean±SD of 163±24 cases per year and had been
practicing angioplasty for 8±5 years. Risk-adjusted measures of both
death and the composite adverse outcome were inversely related to the
number of cases each operator performed annually but bore no relation
to total years of experience. Both adverse outcomes were more closely
related to the logarithm of caseload (for death, r=.37,
P=.01; for death, Q-wave infarction, or bypass surgery,
r=.58, P<.001) than to linear caseload.
Conclusions In this analysis, high-volume operators had a lower incidence of major complications than did lower-volume operators, but the difference was not consistent for all operators. If these data are validated, their implications for hospital, physician, and payer policy will require exploration.
Key Words: angioplasty • coronary disease • mortality
An inverse relation has been described between the incidence of major complications of several procedures, including PTCA, and the number of these procedures performed at a given hospital.1 2 3 4 5 Differences in outcome between high- and low-volume hospitals may be due to greater experience at high-volume centers, to superior technique, or to treatment of sicker patients at low-volume centers.5 Although empirical data relating results to physician experience per se are scant,6 the data obtained from per-hospital analyses have been used to justify the current ACC/AHA recommendations that "a minimum of 75 PTCA procedures (be) performed per year as the ‘primary operator’ in order to be competent to perform PTCA."7 These recommendations have been challenged.8
Even within a hospital with a large procedural volume, yearly physician volume and experience vary. At many such centers, formal teaching conferences, informal sharing of clinical experience, and experienced surgical teams might be expected to mitigate against differences in the procedural outcome of high- and low-volume operators, even if they might otherwise have existed. We sought to build on prior experience in analyzing differences in operator-related coronary interventional procedure outcome9 to ascertain whether yearly procedural outcome or overall experience influenced the procedural outcome of PTCR at five hospitals with considerable PTCA volume and quality-assured databases that would facilitate such an analysis.
Methods
Patient Population
Six hospitals with high-volume (>1000 procedures per year)
programs in interventional cardiology and established
databases were contacted to participate in this study. Each maintains
credentialing standards for individual physician operators and an
interventional database characterized by prospective entry of selected
clinical and angiographic data, routine postprocedure analysis
of ECGs for detection of periprocedural MI, analysis and coding
of complications by trained personnel other than the interventional
cardiologist performing the procedure, and internal audits and checks
for data completeness and consistency.
Five hospital programs agreed to participate and submitted selected data on all interventional procedures performed at their center during calendar years 1993 and 1994 to the central data analysis center at the Cleveland Clinic. The sixth hospital declined, largely because, in contradistinction to the other hospitals, procedures were frequently performed by more than one staff-level physician, and hence, attribution of results to a single physician would be problematic. Because of recent improvements in the data auditing measures at one center, that center agreed to submit data only from July 1, 1994, to December 31, 1994. No patient with attempted treatment during the inclusive dates was excluded from the analysis for any reason.
Baseline Clinical and Angiographic Information
The variables acute MI (onset 
24 hours), age, Canadian
Cardiovascular Society angina class, cardiogenic shock,
left ventricular ejection fraction, modified ACC/AHA lesion
classification score,10 number of diseased vessels, prior
bypass surgery, prior restenosis, sex, and unstable angina were
recorded.
Provider Information
The treating interventionalist of record for each patient
and the number of interventions and total years of performing
interventions for each physician were also recorded.
Procedural Results
The outcome variables in-hospital death, emergency bypass
surgery, and Q-wave MI were tabulated for all patients.
Definitions and Conventions
The variables noted above have been described
elsewhere.9 10 Although our earlier analyses
revealed a nearly linear relation between the modified ACC/AHA lesion
score and adverse outcome,9 our more recent
analyses suggested that A and B1 lesions had a much better
outcome than B2 and C lesions10 ; therefore, we
analyzed lesion characteristic score as both a linear and a
nonlinear risk variable. Emergency bypass surgery referred to that
performed at any time during the index hospitalization because of a
complication of the PTCA. Although definitions used at each hospital
for this variable differed slightly, all stressed the urgency of
the clinical indication for surgery and most specifically required
ongoing ischemia, hemodynamic instability, or
life-threatening anatomy not present before the
intervention. Q-wave infarction was defined as significant Q waves
present after the procedure that were not present before. All
centers obtained postprocedure ECGs on all patients, which were
interpreted by trained cardiologists. For the purposes of this
analysis, a patient treated with PTCA for an acute MI who
developed a Q-wave infarction on ECG was not considered to have had a
complication of the procedure unless he or she died or had emergency
bypass surgery.
Statistical Methods
Baseline characteristics of the treated patients were summarized
in terms of frequencies and percentages for categorical variables
and mean±SD for continuous variables. Multivariable logistic
regression models were used to examine individual and interaction
relations between baseline characteristics and death and also the
composite of death, Q-wave infarction, or bypass surgery.
Models were fitted by the equation probability=ey/(1+ey), where y is a constant plus the sum of all variables’ (valuexß-coefficient). The full study population was used in the model development process, and the predictive performance of the model was internally validated by cross-validation methodology.11 The model was fitted on a randomly selected subset of 80% of the study patients, and the resulting fit was tested on the remaining 20% of the study patients. This process was repeated 10 times to estimate the extent to which the predictive accuracy of the full model was overoptimistic. The measure of predictive discrimination used to characterize model performance was the area under the ROC curve (the c statistic).12 Calibration of the model predictions was assessed by comparison of the average model prediction with the observed event incidence across deciles of risk.
To evaluate the performance of individual operators, a variable coding for each operator was added one at a time to the models. The estimated logistic regression coefficient and standard error were then used to determine an adjusted odds ratio with corresponding 95% confidence limits, which were then converted back to adjusted risk by application of the adjusted odds ratio to the known risk of the event in the population. Only physician operators with at least 30 cases per year in the database were analyzed because of the concern that estimates of the risk of procedural complications for physicians with fewer cases would be highly unstable.9 The relations of operator volume and years of experience to raw and adjusted outcome were evaluated with least-squares linear regression techniques. Physician operators were also divided into quintiles by caseload, and the relationship between caseload quintile and risk-adjusted results in low-risk (ACC/AHA A or B1) and high-risk (ACC/AHA B2 or C) lesions was evaluated.
Results
Patient Population
The baseline characteristics of the patients treated are
enumerated in Table 1
. Most patients were middle-aged
males; about half had unstable angina, 25% prior bypass surgery, 20%
prior PTCR, 60% multivessel disease, and 70% complex ACC/AHA B2 or C
lesions. Major adverse outcomes were seen in 4.5% of patients (death
in 1.3%, Q-wave infarction in 3.5%, emergency bypass surgery in
2.1%).
|
Correlates of Adverse Outcome
Correlates of death and the composite adverse outcome (death,
Q-wave infarction, or bypass surgery) are described in Tables 2 and 3. In-hospital death was
independently correlated with the following variables: shock,
treatment for acute MI, the logarithm of patient age in years, lesion
morphology, female sex, and the number of diseased vessels. The model
derived from these data showed good discriminatory power (area under
the ROC curve, c statistic=0.846), was well calibrated to events
(r=.96), and was not overfitted (cross-validation correction
to the c statistic=0.002). The composite adverse outcome was
independently associated with the variables shock, lesion
morphology, presentation with acute MI, female sex, and no
prior bypass surgery. The model obtained from these data had modest
discriminatory power (c statistic=0.648), was very well calibrated to
events (r=.98), and was not overfitted (cross-validation
correction to the c statistic=0.013).
|
|
Risk Adjustment
The use of these models to provide risk-adjusted outcomes
made a considerable difference compared with the corresponding raw
values for some physicians (see Figs 1 and 2). For the end point of death, half of the physicians
had a relative change of >25%, and one quarter had a change of
40%. For the composite adverse outcome, half of the physicians had a
relative change of >18%, and one quarter had a change of >25%.
|
|
Physician Experience and Outcome
The average physician evaluated in this analysis performed
163±24 (range, 30 to 628) cases per year during 1993 through 1994 and
had been practicing angioplasty or related techniques (eg, atherectomy)
for 8±5 years (range, 1 to 16 years). The results of five physicians
were excluded because they did not perform the requisite number of
cases per year. In aggregate, these five physicians performed 148 cases
during the 2-year study. Their risk of death, Q-wave infarction, or
emergency bypass surgery ranged from 0% to 7.9±8.6%. The relation
between experience and patient outcomes for physicians with 30 cases
per year is described in Table 4. Both death and the
composite adverse outcome were strongly and inversely related to the
number of cases each operator performed annually, but they bore no
relation to the total number of years of physician experience. The
correlations for both death and the composite adverse outcome were
higher for the logarithm of procedural volume than for volume itself,
suggesting an inverse exponential relationship (Fig 3
and Table 4). The relation between operator volume and procedural
results for all patients, as well as those with low- and high-risk
lesions, is shown graphically in Fig 4. For patients
with only low-risk lesions, only the operator quintile with lowest
volume (<70 cases per year) had results that were significantly worse
than the remainder of the group. For patients with high-risk lesions,
the lowest-volume quintile had significantly worse outcome, and the
highest-volume quintile (>270 cases per year) had significantly better
outcomes than the remainder of the group. The effect of caseload on
outcome was consistent for all hospitals.
|
|
|
Discussion
In this analysis of 12 985 patients relating PTCR outcome
to physician experience, we found that risk adjustment made a
considerable (30% relative change) impact on 10% to 40% of
physician operators evaluated. Whether risk adjusted or not, however,
both death (P.01) and the composite adverse outcome of
death, Q-wave infarction, or need for emergency bypass surgery
(P<.001) were significantly and inversely related to
operator caseload (Figs 3
and 4). This occurred even though each
hospital had a very large overall caseload and all are teaching
hospitals to the extent that angioplasty outcome is routinely discussed
at conferences and between colleagues. However, the correlation between
caseload and procedural outcome was far from exact, implying
considerable physician-to-physician variation, some "instability"
of results even for providers with caseloads of 30 to 628 procedures
per year, and limitations of the modeling process. Absolutely no
relation between results and the number of years each physician had
been performing angioplasty was seen.
The inverse relation between the caseload of many surgical procedures and complications is well supported by the results of several studies.1 2 3 To date, the relationship between angioplasty volume and results has been clearly defined only for hospital, but not for physician, volume. Ritchie et al4 analyzed the angioplasty experience in the State of California during 1989 using an administrative data set with ICD-9-CM codes13 and limited patient characteristic variables. These investigators found a strong inverse relation between hospital PTCA volume and the risk of emergency bypass surgery but not overall mortality. The presence of new Q-wave infarction could not be ascertained. Jollis et al5 used a Medicare Provider Analysis and Review (MEDPAR) data set from 1987 through 1990 and found that hospitals performing <200 angioplasties yearly had higher incidences of both death and emergency surgery than did hospitals with larger volumes. Because of the nature of the data set, the risk of MI could not be examined. In a small study, Hamad et al6 suggested that high-volume operators (>100 PTCAs per year) might have less frequent complications with "complex lesions" than "low-volume" operators.
On a largely empirical basis, the ACC/AHA suggested in 1993 that each
physician perform a minimum of 75 angioplasties yearly to have
sufficient experience to continue.7 Some insurance
companies are reimbursing hospitals and physicians for angioplasty only
if the physician has performed 75 cases per year. Not only insurance
companies but also patients14 are becoming increasingly
concerned about physician-specific patient outcome.
Most groups that perform such analyses recognize that the type of patients treated should be accounted for in judging results, but many administrative data sets have major limitations in data veracity and complexity, which limits their capacity to risk adjust.15 Sophisticated "scorecarding"16 of physician results may be beneficial in several ways,9 15 16 but application of incomplete data sets or those without key prognostic variables may lead to sanctioning of competent physicians from practicing or tempt physicians to avoid treating the higher-risk patients.16 17
Possible adverse end points to be used in "scorecarding" analysis such as this have been reviewed.9 Death and Q-wave infarction are inarguably detrimental to a patient’s well-being. One might argue that bypass surgery, as an alternative means of revascularization, should not be considered an adverse outcome. Emergency surgery, however, as defined in this analysis, is usually associated with a lessened likelihood of the patient’s receiving an arterial as opposed to a venous graft, and especially with ongoing ischemia, with a substantial risk of later death, infarction, or need for further revascularization.18 19
Data sets to be used for evaluating physician results should have complete and accurate data, have an outcome that is clearly linked to the responsible physician, and reflect an experience large enough that one can be confident that the overall outcome is unlikely to be due to chance alone.9 In addition, angioplasty databases that have access to clinical and angiographic variables such as hemodynamic instability preceding the procedure and lesion morphology nearly always find them to be independent correlates of adverse outcome; hence, despite recognized limitations,9 they should be a prerequisite for profiling angioplasty operators. The 12 985-patient data set used here meets all these requirements. Furthermore, these patients are typical of patients undergoing PTCR from broad-based series20 and tertiary referral centers.9 21 Finally, the models derived, validated, and used in this analysis have predictive capacity similar to the best reported results for angioplasty outcomes.9 21
The results of this analysis should be assessed in the context of certain study limitations. First, although the likelihood that the general relationship observed between volume and outcome was due to the play of chance was exceedingly small, the exact relation between volume and outcome for any single physician is not nearly so strong: many lower-volume operators had good results during the time period studied. Second, the results were derived from only five hospitals, and one should be conservative about generalizing the findings until they are confirmed. Third, as with all analyses that use regression analysis to adjust for differences between types of patients treated, unmeasured variables may have affected patient outcome. Nonetheless, the concordance of these results with others reported from the surgical literature1 2 3 strongly suggest that they have merit. Fourth, it is possible that some of the relationship between operator volume and results might be explained by the low-volume operator’s lack of immediate access to newer technologies, such as stents, for the "bailout" indication and not be experience per se. Only three physicians in this study were not credentialed for bailout stenting during 1993 through 1994 and would have required the assistance of another physician in this setting, thus limiting our ability to analyze this potential confounding factor. Finally, the technical and pharmacological strategies of PTCR continue to evolve quickly, and the relationship between operator experience and outcome will require reexamination.
The results of this study have three primary implications: (1) physician-to-physician differences in angioplasty outcome appear to be large enough so that it may be useful to develop individual physician profiles; (2) the magnitude of change in adjusted compared with nonadjusted outcomes is so large that non–risk adjusted data should not be used for physician evaluation if appropriate and validated risk-adjustment models are available; (3) if angioplasty procedures are performed by higher-volume operators, then outcomes, on average, will likely be better than if lower-volume operators perform the procedures.
Selected Abbreviations and Acronyms
|
Acknowledgments
The authors appreciate the expert secretarial assistance of Patti Durnwald.
Received November 19, 1996; revision received February 12, 1997; accepted February 28, 1997.
References
- Luft HS, Bunker JP, Enthoven AC. Should
operations be regionalized? The empirical relation between surgical
volume and mortality. N Engl J Med. 1979;301:1364-1369.[Abstract]
- Showstack JA, Rosenfeld KE, Garnick DW, Luft HS,
Schaffarzick RW, Fowles J. Association of volume with outcome of
coronary artery bypass graft surgery: scheduled vs nonscheduled
operations. JAMA. 1987;257:785-789. Erratum,
JAMA. 1987;257:2438.[Abstract]
- Hannan EL, Kilburn H Jr, O’Donnell JF, Lukacik G,
Shields EP. Coronary artery bypass surgery: the
relationship between inhospital mortality rate and surgical volume
after controlling for clinical risk factors. Med
Care. 1991;29:1094-1107.[Medline]
[Order article via Infotrieve]
- Ritchie JL, Phillips KA, Luft HS.
Coronary angioplasty: statewide experience in
California. Circulation. 1993;88:2735-2743.
[Abstract/Free Full Text]
- Jollis JG, Peterson ED, DeLong ER, Mark DB, Collins
SR, Muhlbaier LH, Pryor DB. The relation between the volume of
coronary angioplasty procedures at hospitals treating Medicare
beneficiaries and short-term mortality. N Engl
J Med. 1994;331:1625-1629.
[Abstract/Free Full Text]
- Hamad N, Pichard AD, Lyle HRP, Lindsay J, and members
of the Cardiac Catheterization Laboratory, Washington
Hospital Center. Results of percutaneous transluminal
coronary angioplasty by multiple, relatively low frequency
operators: 1986-1987 experience. Am J Cardiol. 1988;61:1229-1231.[Medline]
[Order article via Infotrieve]
- Ryan TJ, Bauman WB, Kennedy JW, Kereiakes DJ, King SB
III, McCallister BD, Smith SC Jr, Ullyot DJ. Guidelines for
percutaneous transluminal coronary
angioplasty. Circulation. 1993;88:2987-3007.
[Free Full Text]
- O’Neill WW, Griffin JJ, Stone G, Brodie B, Jones DE,
Sachs D, Esente P, Spain M, Ayres M, Grines CL. Operator and
institutional volume do not affect the procedural outcome of primary
angioplasty therapy. J Am Coll Cardiol.
1996;(special issue):13A. Abstract.
- Ellis SG, Omoigui N, Bittl JA, Lincoff AM, Wolfe MW,
Howell G, Topol EJ. Analysis and comparison of operator
specific outcomes in interventional cardiology: from a
multicenter database of 4860 quality-controlled procedures.
Circulation. 1996;93:431-439.
[Abstract/Free Full Text]
- Cowley MJ, Vandormael M, Topol EJ, Whitlow PL, Dan LS,
Bulle TM, Ellis SG, for the MAPS Study Group. Is traditionally defined
complete revascularization needed for patients with
multivessel disease treated by elective coronary angioplasty?
J Am Coll Cardiol. 1993;22:1289-1297.[Abstract]
- Gong G. Cross-validation, the jackknife, and the
bootstrap: excess error estimation in forward logistic
regression. J Am Stat Assoc. 1986;81:108-113.
- Egan JP. Signal Detection Theory and ROC
Analysis. New York, NY: Academic Press; 1975.
- The International Classification of Diseases, 9th
revision, clinical modification (ICD-9-CM). 2nd ed. Vol I.
Diseases: Tabular List. Washington, DC: Government Printing
Office; 1980. DHHS publication (PHS) 80-1260.
- Zimman D. Heart surgeons rated: state reveals
patient-mortality records. Newsday, Nassau and
Suffolk edition. December 18, 1991:3.
- Kassirer JP. The use and abuse of practice
profiles. N Engl J Med. 1994;330:634-636.
[Free Full Text]
- Topol EJ, Block PC, Holmes DR, Klinke WP, Brinker
JA. Readiness for the scorecard era in
cardiovascular medicine. Am J
Cardiol. 1995;75:1170-1173.[Medline]
[Order article via Infotrieve]
- Omoigui NA, Miller DP, Brown KJ, Annan K, Cosgrove D
III, Lytle B, Loop F, Topol EJ. Outmigration for
coronary bypass surgery in the era of public dissemination of
clinical outcomes. Circulation. 1996;93:27-33.
[Abstract/Free Full Text]
- Talley JD, Weintraub WS, Roubin GS, Douglas JS Jr,
Anderson HV, Jones EL, Morris DC, Liberman HA, Craver JM, Guyton RA,
King SB III. Failed elective percutaneous
transluminal coronary angioplasty requiring coronary
artery bypass surgery: in-hospital and late clinical outcome at 5
years. Circulation. 1990;82:1203-1213.
[Abstract/Free Full Text]
- Kahn JK, Rutherford BD, McConahay DR, Johnson WL,
Giorgi LV, Shimshak TM, Hartzler GO. Outcome following emergency
coronary artery bypass grafting for failed elective balloon
coronary angioplasty in patients with prior coronary
bypass. Am J Cardiol. 1990;66:285-288.[Medline]
[Order article via Infotrieve]
- Hannan El, Arani DT, Johnson LW, Kemp HG, Lukacik
G. Percutaneous transluminal coronary
angioplasty in New York State: risk factors and outcomes.
JAMA. 1993;268:3092-3097.
- Myler RK, Shaw RE, Stertzer SH, Hecht HS, Ryan C,
Rosenblum J, Cumberland DC, Murphy MC, Hansell HN, Hidalgo B.
Lesion morphology and coronary angioplasty: current experience
and analysis. J Am Coll Cardiol. 1992;19:1641-1652.[Abstract]
This article has been cited by other articles:
 |
|
 |
|
  B Kunadian, J Dunning, R Das, A P Roberts, R Morley, A J Turley, D Twomey, J A Hall, R A Wright, A G C Sutton, et al. External validation of established risk adjustment models for procedural complications after percutaneous coronary intervention Heart, August 1, 2008; 94(8): 1012 - 1018. [Abstract] [Full Text] [PDF]
|
|
|
|
 |
|
 R. Dugnani and F.K. Chang In Vitro Atherosclerotic Plaque Characterization by Acoustic Impedance Monitoring, Part I: Sensor Modeling, Design, and Fabrication Journal of Intelligent Material Systems and Structures, July 1, 2008; 19(7): 815 - 826. [Abstract] [PDF]
|
|
|
|
|
|
R Zahn, M Gottwik, M Hochadel, J Senges, U Zeymer, A Vogt, T Meinertz, R Dietz, K E Hauptmann, E Grube, et al. Volume-outcome relation for contemporary percutaneous coronary interventions (PCI) in daily clinical practice: is it limited to high-risk patients? Results from the Registry of Percutaneous Coronary Interventions of the Arbeitsgemeinschaft Leitende Kardiologische Krankenhausarzte (ALKK) Heart, March 1, 2008; 94(3): 329 - 335. [Abstract] [Full Text] [PDF]
|
|
|
|
 |
|
 S. B. King III, T. Aversano, W. L. Ballard, R. H. Beekman III, M. J. Cowley, S. G. Ellis, D. P. Faxon, E. L. Hannan, J. W. Hirshfeld Jr, A. K. Jacobs, et al. ACCF/AHA/SCAI 2007 Update of the Clinical Competence Statement on Cardiac Interventional Procedures: A Report of the American College of Cardiology Foundation/American Heart Association/American College of Physicians Task Force on Clinical Competence and Training (Writing Committee to Update the 1998 Clinical Competence Statement on Recommendations for the Assessment and Maintenance of Proficiency in Coronary Interventional Procedures) J. Am. Coll. Cardiol., July 3, 2007; 50(1): 82 - 108. [Full Text] [PDF]
|
|
|
|
 |
|
 J. P. Mathew, K. Glas, C. A. Troianos, P. Sears-Rogan, R. Savage, J. Shanewise, J. Kisslo, S. Aronson, S. Shernan, and for the Council for Intraoperative Echocardiograph ASE/SCA Recommendations and Guidelines for Continuous Quality Improvement in Perioperative Echocardiography Anesth. Analg., December 1, 2006; 103(6): 1416 - 1425. [Full Text] [PDF]
|
|
|
|
|
|
C. Wu, E. L. Hannan, G. Walford, J. A. Ambrose, D. R. Holmes Jr, S. B. King III, L. T. Clark, S. Katz, S. Sharma, and R. H. Jones A Risk Score to Predict In-Hospital Mortality for Percutaneous Coronary Interventions J. Am. Coll. Cardiol., February 7, 2006; 47(3): 654 - 660. [Abstract] [Full Text] [PDF]
|
|
|
|
 |
|
 T. P. Wharton Jr, E. C. Keeley, C. L. Grines, T. P. Wharton Jr, E. C. Keeley, and C. L. Grines The Case for Community Hospital Angioplasty Circulation, November 29, 2005; 112(22): 3509 - 3534. [Full Text] [PDF]
|
|
|
|
|
|
M. Moscucci, D. Share, D. Smith, M. J. O'Donnell, A. Riba, R. McNamara, T. Lalonde, A. C. Defranco, K. Patel, E. Kline Rogers, et al. Relationship Between Operator Volume and Adverse Outcome in Contemporary Percutaneous Coronary Intervention Practice: An Analysis of a Quality-Controlled Multicenter Percutaneous Coronary Intervention Clinical Database J. Am. Coll. Cardiol., August 16, 2005; 46(4): 625 - 632. [Abstract] [Full Text] [PDF]
|
|
|
|
 |
|
 J. A. Brinker, C. J. Davidson, and W. Laskey Preventing in-hospital cardiac and renal complications in high-risk PCI patients Eur. Heart J. Suppl., August 1, 2005; 7(suppl_G): G13 - G24. [Abstract] [Full Text] [PDF]
|
|
|
|
 |
|
 S. R. Mehta, C. P. Cannon, K. A. A. Fox, L. Wallentin, W. E. Boden, R. Spacek, P. Widimsky, P. A. McCullough, D. Hunt, E. Braunwald, et al. Routine vs Selective Invasive Strategies in Patients With Acute Coronary Syndromes: A Collaborative Meta-analysis of Randomized Trials JAMA, June 15, 2005; 293(23): 2908 - 2917. [Abstract] [Full Text] [PDF]
|
|
|
|
|
|
S. M. Kansagra, L. H. Curtis, and K. A. Schulman Regionalization of Percutaneous Transluminal Coronary Angioplasty and Implications for Patient Travel Distance JAMA, October 13, 2004; 292(14): 1717 - 1723. [Abstract] [Full Text] [PDF]
|
|
|
|
|
|
M. Singh, C. S. Rihal, R. J. Lennon, K. N. Garratt, and D. R. Holmes Jr Comparison of Mayo Clinic risk score and American College of Cardiology/American Heart Association lesion classification in the prediction of adverse cardiovascular outcome following percutaneous coronary interventions J. Am. Coll. Cardiol., July 21, 2004; 44(2): 357 - 361. [Abstract] [Full Text] [PDF]
|
|
|
|
|
|
D. E. Cutlip, K. K. L. Ho, R. E. Kuntz, and D. S. Baim Risk assessment for percutaneous coronary intervention: our version of the weather report? J. Am. Coll. Cardiol., December 3, 2003; 42(11): 1896 - 1899. [Full Text] [PDF]
|
|
|
|
|
|
M. Singh, C. S. Rihal, F. Selzer, K. E. Kip, K. Detre, and D. R. Holmes Jr Validation of Mayo clinic risk adjustment model for in-hospital complications after percutaneous coronary interventions, using the National Heart, Lung, and Blood Institute dynamic registry J. Am. Coll. Cardiol., November 19, 2003; 42(10): 1722 - 1728. [Abstract] [Full Text] [PDF]
|
|
|
|
|
|
N. Seshadri, P. L. Whitlow, N. Acharya, P. Houghtaling, E. H. Blackstone, and S. G. Ellis Emergency Coronary Artery Bypass Surgery in the Contemporary Percutaneous Coronary Intervention Era Circulation, October 29, 2002; 106(18): 2346 - 2350. [Abstract] [Full Text] [PDF]
|
|
|
|
|
|
B. A. Vakili, R. Kaplan, and D. L. Brown Volume-Outcome Relation for Physicians and Hospitals Performing Angioplasty for Acute Myocardial Infarction in New York State Circulation, October 30, 2001; 104(18): 2171 - 2176. [Abstract] [Full Text] [PDF]
|
|
|
|
 |
|
 M Gottwik, R Zahn, R Schiele, S Schneider, A.K Gitt, L Fraunberger, C Bossaller, H.G Glunz, E Altmann, W Rosahl, et al. Differences in treatment and outcome of patients with acute myocardial infarction admitted to hospitals with compared to without departments of cardiology. Results from the pooled data of the Maximal Individual Therapy in Acute Myocardial Infarction (MITRA 1+2) Registries and the Myocardial Infarction Registry (MIR) Eur. Heart J., October 1, 2001; 22(19): 1794 - 1801. [Abstract] [PDF]
|
|
|
|
|
|
S. C. Smith Jr, J. T. Dove, A. K. Jacobs, J. Ward Kennedy, D. Kereiakes, M. J. Kern, R. E. Kuntz, J. J. Popma, H. V. Schaff, D. O. Williams, et al. ACC/AHA guidelines for percutaneous coronary intervention (revision of the 1993 PTCA guidelines): A report of the American College of Cardiology/ American Heart Association Task Force on practice guidelines (Committee to revise the 1993 guidelines for percutaneous transluminal coronary angioplasty) endorsed by the Society for Cardiac Angiography and Interventions J. Am. Coll. Cardiol., June 15, 2001; 37(8): 2239 - 2239. [Full Text] [PDF]
|
|
|
|
|
|
D. R. Holmes Jr, P. B. Berger, K. N. Garratt, V. Mathew, M. R. Bell, G. W. Barsness, S. T. Higano, D. E. Grill, L. N. Hammes, and C. S. Rihal Application of the New York State PTCA Mortality Model in Patients Undergoing Stent Implantation Circulation, August 1, 2000; 102(5): 517 - 522. [Abstract] [Full Text] [PDF]
|
|
|
|
|
|
J. Lindsay Jr., E. E. Pinnow, and A. D. Pichard Frequency of major adverse cardiac events within one month of coronary angioplasty: a useful measure of operator performance J. Am. Coll. Cardiol., December 1, 1999; 34(7): 1916 - 1923. [Abstract] [Full Text] [PDF]
|
|
|
|
|
|
S. G. Ellis, V. Guetta, D. Miller, P. L. Whitlow, and E. J. Topol Relation Between Lesion Characteristics and Risk With Percutaneous Intervention in the Stent and Glycoprotein IIb/IIIa Era : An Analysis of Results From 10 907 Lesions and Proposal for New Classification Scheme Circulation, November 9, 1999; 100(19): 1971 - 1976. [Abstract] [Full Text] [PDF]
|
|
|
|
|
|
M. Moscucci, G. T. O'Connor, S. G. Ellis, D. J. Malenka, J. Sievers, E. R. Bates, D. W. M. Muller, S. W. Werns, E. K. Rogers, D. Karavite, et al. Validation of risk adjustment models for in-hospital percutaneous transluminal coronary angioplasty mortality on an independent data set J. Am. Coll. Cardiol., September 1, 1999; 34(3): 692 - 697. [Abstract] [Full Text] [PDF]
|
|
|
|
|
|
A. K. Berger, K. A. Schulman, B. J. Gersh, S. Pirzada, J. A. Breall, A. E. Johnson, and N. R. Every Primary Coronary Angioplasty vs Thrombolysis for the Management of Acute Myocardial Infarction in Elderly Patients JAMA, July 28, 1999; 282(4): 341 - 348. [Abstract] [Full Text] [PDF]
|
|
|
|
|
|
Th. Budde, M. Haude, H.W. Hopp, S. Kerber, G. Caspari, G. Fassbender, M. Fingerhut, I. Novopashenny, Y. Ogurol, G. Breithardt, et al. A prognostic computer model to individually predict post-procedural complications in interventional cardiology; the INTERVENT Project Eur. Heart J., March 1, 1999; 20(5): 354 - 363. [Abstract] [PDF]
|
|
|
|
|
|
A. Kastrati, F.-J. Neumann, and A. Schomig Operator volume and outcome of patients undergoing coronary stent placement J. Am. Coll. Cardiol., October 1, 1998; 32(4): 970 - 976. [Abstract] [Full Text] [PDF]
|
|
|
|
 |
|
 In PTCA, Practice Makes Perfect Journal Watch Cardiology, June 20, 1997; 1997(620): 3 - 3. [Full Text]
|
|
| |||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||