Journal of the American College of Cardiology Vol. 35, No. 4, by the American College of Cardiology ISSN /00/$20.

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1 Journal of the American College of Cardiology Vol. 35, No. 4, by the American College of Cardiology ISSN /00/$20.00 Published by Elsevier Science Inc. PII S (99) Utilization of Coronary Angiograhy and Revascularization After Acute Myocardial Infarction in and Risk Stratified by the American College of Cardiology/ American Heart Association Guidelines Prasad K. Kilaru, MD,* Russell F. Kelly, MD, FACC,* James E. Calvin, MD, FACC,* Joseh E. Parrillo, MD, FACC Chicago, Illinois OBJECTIVES BACKGROUND METHODS RESULTS CONCLUSIONS We sought to determine whether men and women are equally likely to receive coronary angiograhy and revascularization after acute myocardial infarction (AMI) when they are risk stratified according to American College of Cardiology/American Heart Association (ACC/ AHA) ractice guidelines for ost-mi care. Several revious studies have suggested that women may undergo angiograhy and revascularization rocedures less frequently than men. In 439 consecutive atients admitted to a ublic hosital with AMI, rates of coronary angiograhy and revascularization were comared in men and women categorized, according to ACC/AHA ractice guidelines, as having strong (class I or IIa) or weaker (class IIb) indications for angiograhy. were older and more likely to be diabetic or hyertensive, but men and women were equally likely to meet class I/IIa criteria for ost-mi angiograhy (both 51%). Angiograhy rates were nearly identical in men and women overall (63% vs. 64%), as well as in atients in class I/IIa (80% vs. 82%) and class IIb (46% vs. 46%) (all 0.80, with 80% ower to detect imortant differences); the only multivariate redictors of ost-mi angiograhy were age and ACC/AHA class. Significant coronary artery disease was equally revalent in men and women undergoing angiograhy, and men and women were equally likely to undergo revascularization, whether they were in class I/IIa (both 55%, 0.90) or class IIb (59% vs. 58%, 0.88). No significant differences in mortality were noted between men and women. Desite being older and having more risk factors than men, women were equally likely to undergo coronary angiograhy and revascularization rocedures after AMI, and they had in-hosital clinical outcomes that were at least as favorable. (J Am Coll Cardiol 2000;35: 974 9) 2000 by the American College of Cardiology Several studies have found that women may be less likely than men to undergo coronary angiograhy and revascularization rocedures after acute myocardial infarction (AMI) (1 5) and in other settings (6 8), although other studies have found no gender differences in rocedural rates (9,10). Determining whether observed differences in angiograhy and revascularization rates reflect inaroriate care in From the *Division of Cardiology, Cook County Hosital, and Section of Cardiology, Rush Presbyterian St. Luke s Medical Center, Chicago, Illinois. This work was erformed internally with institutional funds. Manuscrit received Aril 30, 1999; revised manuscrit received October 25, 1999, acceted December 2, women has been confounded by a number of factors. Until late in life, coronary artery disease (CAD) is less revalent in women than in men (11). More women have atyical symtoms (12), and false-ositive stress tests are more common in women (12). are older and have more comorbid conditions when they resent with CAD, which may limit rocedure utilization (13). One method of determining the aroriateness of care is to comare recommended standards of ractice with actual rates of rocedure utilization. The American College of Cardiology (ACC) and American Heart Association (AHA) have ublished guidelines for the care of atients with AMI (14,15). These guidelines categorize indications

2 JACC Vol. 35, No. 4, 2000 March 15, 2000:974 9 Kilaru et al. Post-MI Angiograhy in and 975 Abbreviations and Acronyms ACC/AHA American College of Cardiology/American Heart Association AMI acute myocardial infarction CAD coronary artery disease for erforming coronary angiograhy as class I (usually indicated, always accetable), class IIa (controversial, but favored owing to the weight of evidence and/or oinion), class IIb (not well established by evidence, but robably not harmful) or class III (not indicated). In the resent study, we comared the utilization of coronary angiograhy in men and women with AMI who had strong (ACC/AHA class I or IIa) or weak (class IIb) criteria for erforming ost-mi angiograhy. METHODS Data from all atients (n 462) diagnosed with AMI at Cook County Hosital between 1994 and 1997 were rosectively collected and entered into a data base. The criteria used for the diagnosis of AMI were elevation of creatine kinase MB fraction in conjunction with a clinical resentation and/or electrocardiograhic evidence consistent with a diagnosis of AMI. Twenty-three atients undergoing rimary angiolasty (6 women and 17 men) were excluded from the resent study, leaving a final study grou of 439 atients. Data were initially abstracted from atient charts by trained nursing ersonnel and were audited for accuracy by two cardiologists who reviewed the medical records and coronary angiograms, when necessary. Clinical data collected included age, gender, traditional coronary risk factors (e.g., hyertension, diabetes mellitus, hyerliidemia, smoking, family history of early CAD), Q wave versus non Q wave MI and comlications. Patients were risk stratified according to the ACC/AHA guidelines ublished in 1990 (14). (Although new guidelines were issued in 1996 [15], the 1990 criteria were in force during most of this study eriod.) Patients were considered to have a stronger (class I or IIa) indication for coronary angiograhy if any of the following clinical features were resent: hemodynamic instability or shock, recurrent ischemia, evidence of ischemia by noninvasive testing, mechanical comlication (acute mitral regurgitation due to aillary muscle dysfunction or ruture, ventricular setal defect, seudoaneurysm), congestive heart failure, left ventricular ejection fraction 40% or malignant arrhythmia. Patients were considered to have a weaker (class IIb) indication for angiograhy if they did not meet any of the criteria outlined earlier and if they had received thrombolytic theray, had exerienced a non Q wave MI or were 45 years old. No atients were included in the resent study in whom angiograhy was categorized as class III (not indicated) according to ACC/AHA criteria. Table 1. Clinical Characteristics Angiograhic data were obtained from the final rocedure reort (and from review of angiograms, when necessary) and included the resence and extent of CAD (defined as 50% diameter stenosis) and left ventricular ejection fraction. Performance of ercutaneous transluminal coronary angiolasty and coronary artery byass graft surgery was determined from chart review, catheterization laboratory records and cardiovascular surgery records. Categoric variables were comared using the chi-square test or Fisher exact test. Continuous variables were comared using two-sided t tests. Multile logistic regression analysis was erformed using all variables with a univariate value A value 0.05 was considered significant. This study was aroved by the Scientific Committee at Cook County Hosital. RESULTS (n 265) (n 174) Age (years) Coronary risk factors Hyertension 63% 78% Diabetes mellitus 29% 41% Smoking 46% 37% 0.06 Hyerliidemia 10% 12% 0.64 Family history 33% 32% 0.87 Previous MI (%) 18% 10% 0.03 History of congestive 19% 20% 0.95 heart failure (%) Previous revascularization 8% 6% 0.76 (%) Q wave MI 42% 35% 0.16 Anterior MI 41% 41% 0.95 Heart rate (beats/min) Systolic blood ressure (mm Hg) Diastolic blood ressure (mm Hg) Thrombolysis 20% 15% 0.21 Data are resented as the mean value SD or ercentage of atients, unless otherwise indicated. MI myocardial infarction. The clinical characteristics of the atients are shown in Table 1. were significantly older than men, and more women were hyertensive or diabetic; a trend toward lower revalence of smoking was noted in women. No significant differences between men and women were noted in the roortion of atients with Q wave or non Q wave MIs, in the ercentage of atients with anterior infarction or in frequency of thrombolytic use. There was no significant difference between the roortions of men and women who were classified as having strong (class I/IIa) or weaker (class IIb) indications for coronary angiograhy according to ACC/AHA guidelines

3 976 Kilaru et al. JACC Vol. 35, No. 4, 2000 Post-MI Angiograhy in and March 15, 2000:974 9 Table 2. Indications for Angiograhy (n 265) (n 174) Patients in ACC/AHA class I/IIa 51% 51% 0.95 Patients in ACC/AHA class IIb 49% 49% ACC/AHA class I/IIa indications* 0.92 Ischemia/reinfarction 25% 28% Hemodynamic instability 15% 16% Malignant arrhythmia 9% 9% Heart failure/left ventricular dysfunction 16% 13% Mechanical comlication 1% 1% Patients who underwent angiograhy 63% 64% 0.85 *Some atients had more than one indication for angiograhy. ACC/AHA American College of Cardiology/American Heart Association. (Table 2), nor were the secific indications for angiograhy different. Overall angiograhy rates were nearly identical in men and women (Table 2). Table 3 summarizes the characteristics, angiograhic findings and revascularization rates for atients with ACC/ AHA class I/IIa indications for angiograhy. There were no significant differences in angiograhy rates between men and women, and there were no differences in the resence or extent of CAD between men and women who underwent angiograhy. Rates of coronary angiolasty, byass surgery and overall revascularization were very similar in the men and women found to have significant CAD. Table 4 summarizes the characteristics, angiograhic findings and revascularization rates for atients with ACC/ AHA class IIb indications for angiograhy. The women in this category were significantly older than the men. There were no significant differences in angiograhy rates between men and women or in the resence or extent of CAD. Finally, there were no significant differences in the rates of coronary angiolasty, byass surgery or overall revascularization between men and women found to have significant CAD. At the rates of coronary angiograhy found in this study, the ower to detect imortant differences ( 20%) in utilization between men and women was 80% for the overall grou and for each ACC/AHA class. After adjustment for baseline clinical characteristics, there were still no significant differences in catheterization rates between men and women, in the overall grou (Table 5) or when the atients were risk stratified according to ACC/AHA criteria (Tables 6 and 7). Although younger atients were less likely to undergo angiograhy, there was no significant interaction between age and gender; for examle, angiograhy rates in men and women older or younger than age 65 years were not significantly different ( 0.76). The overall in-hosital mortality rate was 7.8%. There was no significant difference in mortality between men and women (9.1% vs. 5.7%, 0.27). The mortality rate in atients with a class I/IIa indication for angiograhy was 14.4%, as comared with 1.0% in atients with a class IIb indication ( ). There were no significant differences in mortality rates between men and women in class Table 3. Patients in Class I/IIa According to the American College of Cardiology/American Heart Association (n 134) (n 89) Age (years) Patients who underwent angiograhy 80% 82% 0.82 Significant CAD (ercentage of 82% 86% 0.63 atients who had angiograhy) One vessel 35% 31% 0.38 Two vessels 21% 32% Three vessels or LMCA 26% 24% Left ventricular ejection fraction 48 11% 50 11% 0.33 Revascularization (ercentage of 55% 55% 0.90 atients with CAD) Coronary angiolasty 33% 34% Byass surgery 22% 21% Data are resented as the mean value SD or ercentage of atients. ACC/AHA American College of Cardiology/American Heart Association; CAD coronary artery disease; LMCA left main coronary artery.

4 JACC Vol. 35, No. 4, 2000 March 15, 2000:974 9 Kilaru et al. Post-MI Angiograhy in and 977 Table 4. Patients in Class IIb According to the American College of Cardiology/American Heart Association (n 131) (n 85) Age (years) Patients who underwent angiograhy (%) 46% 46% 0.90 Significant CAD (ercentage of atients 73% 79% 0.65 who had angiograhy) One vessel 28% 41% 0.53 Two vessels 20% 13% Three vessels or LMCA 25% 26% Left ventricular ejection fraction 52 11% 53 11% 0.76 Revascularization (ercentage of atients 59% 58% 0.88 with CAD) Coronary angiolasty 39% 36% Byass surgery 21% 23% Data are resented as the mean value SD or ercentage of atients. Abbreviations as in Table 3. I/IIa (16.5% vs. 11.2%, 0.36) or class IIb (1.5% vs. 0%, 0.72). DISCUSSION A number of studies have found that women are less likely than men to undergo coronary angiograhy and revascularization rocedures after AMI. Studies from a national data base of Medicare atients with AMI (1 3,5) and from the National Hosital Discharge Survey (4) found that women admitted to the hosital for AMI were significantly less likely than men to undergo catheterization, coronary angiolasty or byass surgery. Angiograhy has also been demonstrated to be utilized less often in women in other clinical settings as well. One study of nearly 400 atients with susected CAD undergoing exercise nuclear testing at four different New York City hositals found that women with abnormal nuclear stress results were only one-tenth as likely as men to be referred for angiograhy (8), and other studies have also found lower rates of rocedures in women as comared with men (7). Large, state-wide studies of hosital discharges (6,16) have found that women were significantly less likely to undergo coronary angiolasty and byass surgery. In atients without AMI, the gender disarity in angiograhy rates may be attributed to clinical differences. are more likely to resent with atyical symtoms (12). Coronary artery disease is less revalent even in women with tyical angina (11), and abnormal stress tests (including abnormal imaging studies) are more likely to be false ositives (12). develo CAD at a later age than do men and often have more coronary risk factors and comorbid conditions, and age has been shown to be indeendently associated with rates of rocedure utilization (13). Finally, it is ossible that women may refer less invasive treatment strategies (17). Other, usually more recent studies have found no differences in rocedural rates between men and women. After Table 5. Predictors of Use of Angiograhy After Acute Myocardial Infarction r OR (95% CI) Univariate analysis Female gender ( ) Older age ( ) Hyertension ( ) Diabetes mellitus ( ) Smoking history ( ) Hyerliidemia ( ) Family history ( ) ACC/AHA guideline class IIb ( ) Q wave MI ( ) Multivariate analysis Age ( ) ACC/AHA guideline class IIb ( ) ACC/AHA American College of Cardiology/American Heart Association; CI confidence interval; MI myocardial infarction; OR odds ratio.

5 978 Kilaru et al. JACC Vol. 35, No. 4, 2000 Post-MI Angiograhy in and March 15, 2000:974 9 Table 6. Predictors of Use of Angiograhy After Acute Myocardial Infarction in Patients in Class I/IIa According to the American College of Cardiology/American Heart Association r OR (95% CI) Univariate analysis Female gender ( ) Older age ( ) Hyertension ( ) Diabetes mellitus ( ) Smoking history ( ) Hyerliidemia ( ) Family history ( ) Q wave MI ( ) Multivariate analysis Age ( ) Abbreviations as in Table 5. controlling for clinical characteristics, Mark et al. (9) found no differences in referrals for angiograhy between men and women. Krumholz et al. (10) controlled for age and found no differences in angiograhy rates between men and women with AMI. Wong et al. (18) found that in-hosital angiograhy rates were similar for men and women. In the Survival and Ventricular Enlargement (SAVE) trial, women had lower rates of coronary angiograhy before the index MI, desite reorting symtoms consistent with greater functional disability (19). However, after the index AMI, rates of angiograhy and revascularization rocedures were similar for women and men (19). This has been termed the Yentl syndrome; once a woman has a documented infarct and behaves like a man, she may be treated like a man. Present study. The findings of the resent study are in agreement with the more recent studies. In 439 consecutive atients with AMI who did not undergo rimary angiolasty, we found no differences in the rates of coronary angiograhy between men and women (80% vs. 82%) or revascularization rocedures (55% for both). In addition, revascularization rates in this study of atients in an innercity ublic hosital were comarable to those in other reorts, including studies which found differences in utilization rates between men and women (10,20). Although mortality rates for women were significantly higher after an AMI in some reorts (20 22), adjustment for clinical characteristics minimizes differences in outcomes between men and women (23). in the resent study tended to have lower (but not statistically significant) in-hosital mortality rates (5.7% vs. 9.1% 0.27), a finding which held in both ACC/AHA class I/IIa and class IIb subgrous, desite the fact that these women were older and had more risk factors for CAD. It is ossible that the similarity in angiograhy and revascularization rates contributed to the similarity in outcomes between men and women. The major strength of the resent study is that rocedure utilization was comared in men and women who were classified by a recognized standard of care the ACC/AHA guidelines. Analyzing rocedure utilization according to the same criteria that hysicians should aly in making man- Table 7. Predictors of Use of Angiograhy After Acute Myocardial Infarction in Patients in Class IIb According to the American College of Cardiology/American Heart Association r OR (95% CI) Univariate analysis Female gender ( ) Older age ( ) Hyertension ( ) Diabetes mellitus ( ) Smoking history ( ) Hyerliidemia ( ) Family history ( ) Q wave MI ( ) Multivariate analysis Age ( ) Smoking history ( ) Abbreviations as in Table 5.

6 JACC Vol. 35, No. 4, 2000 March 15, 2000:974 9 Kilaru et al. Post-MI Angiograhy in and 979 agement decisions may rovide valuable insight into the aroriateness of clinical conduct; indeed, in the resent study, ACC/AHA class was an indeendent redictor of erformance of angiograhy after AMI. Furthermore, these data reresent actual ractice in a consecutive, unselected grou of atients in a real-world setting, rather than a select atient grou, as in multicenter trials (19) or Medicare data base reorts (1 3,5). Such studies may include more homogeneous grous of atients that are less comlex or older than those seen in a tyical clinical environment. Study limitations. Although the clinical, angiograhic and rocedure data were rosectively collected, and the methods and end oints were rosectively identified, this is a retrosective analysis, with the attendant limitations. It is ossible that studying a larger number of atients might have revealed a difference in rocedure utilization between men and women, but no trends in the data suggest that larger numbers might have detected such a difference. Another limitation is that the findings reflect the ractice at a single center; demonstrating a lack of bias in this institution does not necessarily mean that the results are generalizable to other institutions. Finally, long-term follow-u with resect to either outcomes or erformance of later angiograhy would rovide additional information. Conclusions. We found no evidence for gender disarity in utilization of coronary angiograhy or revascularization rocedures in men and women admitted to a large innercity teaching hosital with AMI. We also found no differences in in-hosital mortality rates, desite the fact that women were older and had more risk factors. It is ossible that the similarity in angiograhy and revascularization rates among atients with ACC/AHA criteria for undergoing angiograhy contributed to the similarity in outcomes between men and women. These data rovide further evidence that although resentations may differ as a function of gender, hysicians resond aroriately to the needs of the female oulation. Rerint requests and corresondence: Dr. Russell F. Kelly, 1725 W. Harrison Street, Suite 1159, Chicago, Illinois rkelly@rush.edu. REFERENCES 1. Gatsonis CA, Estein AM, Newman TB, Normand SL, McNeil BJ. Variations in the utilization of coronary angiograhy for elderly atients with an acute myocardial infarction: an analysis using hierarchical logistic regression. Med Care 1995;33: Udvarhelyi IS, Gatsonis C, Estein AM, et al. Acute myocardial infarction in the Medicare oulation: rocess of care and clinical outcomes. JAMA 1992;268: Pashos CL, Newhouse JP, McNeil BJ. 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