John G. Canto

The volume of primary angioplasty procedures and survival after acute myocardial infarction. National Registry of Myocardial Infarction 2 Investigators.

BACKGROUND There is an inverse relation between mortality from cardiovascular causes and the number of elective cardiac procedures (coronary angioplasty, stenting, or coronary bypass surgery) performed by individual practitioners or hospitals. However, it is not known whether patients with acute myocardial infarction fare better at centers where more patients undergo primary angioplasty or thrombolytic therapy than at centers with lower volumes. METHODS We analyzed data from the National Registry of Myocardial Infarction to determine the relation between the number of patients receiving reperfusion therapy (primary angioplasty or thrombolytic therapy) and subsequent in-hospital mortality. A total of 450 hospitals were divided into quartiles according to the volume of primary angioplasty. Multiple logistic-regression models were used to determine whether the volume of primary angioplasty procedures was an independent predictor of in-hospital mortality among patients undergoing this procedure. Similar analyses were performed for patients receiving thrombolytic therapy at 516 hospitals. RESULTS In-hospital mortality was 28 percent lower among patients who underwent primary angioplasty at hospitals with the highest volume than among those who underwent angioplasty at hospitals with the lowest volume (adjusted relative risk, 0.72; 95 percent confidence interval, 0.60 to 0.87; P<0.001). This lower rate, which represented 2.0 fewer deaths per 100 patients treated, was independent of the total volume of patients with myocardial infarction at each hospital, year of admission, and use or nonuse of adjunctive pharmacologic therapies. There was no significant relation between the volume of thrombolytic interventions and in-hospital mortality among patients who received thrombolytic therapy (7.0 percent for patients in the highest-volume hospitals vs. 6.9 percent for those in the lowest-volume hospitals, P=0.36). CONCLUSIONS Among hospitals in the United States that have full interventional capabilities, a higher volume of angioplasty procedures is associated with a lower mortality rate among patients undergoing primary angioplasty, but there is no association between volume and mortality for thrombolytic therapy.

Association of Age and Sex With Myocardial Infarction Symptom Presentation and In-Hospital Mortality

CONTEXT Women are generally older than men at hospitalization for myocardial infarction (MI) and also present less frequently with chest pain/discomfort. However, few studies have taken age into account when examining sex differences in clinical presentation and mortality. OBJECTIVE To examine the relationship between sex and symptom presentation and between sex, symptom presentation, and hospital mortality, before and after accounting for age in patients hospitalized with MI. DESIGN, SETTING, AND PATIENTS Observational study from the National Registry of Myocardial Infarction, 1994-2006, of 1,143,513 registry patients (481,581 women and 661,932 men). MAIN OUTCOME MEASURES We examined predictors of MI presentation without chest pain and the relationship between age, sex, and hospital mortality. RESULTS The proportion of MI patients who presented without chest pain was significantly higher for women than men (42.0% [95% CI, 41.8%-42.1%] vs 30.7% [95% CI, 30.6%-30.8%]; P < .001). There was a significant interaction between age and sex with chest pain at presentation, with a larger sex difference in younger than older patients, which became attenuated with advancing age. Multivariable adjusted age-specific odds ratios (ORs) for lack of chest pain for women (referent, men) were younger than 45 years, 1.30 (95% CI, 1.23-1.36); 45 to 54 years, 1.26 (95% CI, 1.22-1.30); 55 to 64 years, 1.24 (95% CI, 1.21-1.27); 65 to 74 years, 1.13 (95% CI, 1.11-1.15); and 75 years or older, 1.03 (95% CI, 1.02-1.04). Two-way interaction (sex and age) on MI presentation without chest pain was significant (P < .001). The in-hospital mortality rate was 14.6% for women and 10.3% for men. Younger women presenting without chest pain had greater hospital mortality than younger men without chest pain, and these sex differences decreased or even reversed with advancing age, with adjusted OR for age younger than 45 years, 1.18 (95% CI, 1.00-1.39); 45 to 54 years, 1.13 (95% CI, 1.02-1.26); 55 to 64 years, 1.02 (95% CI, 0.96-1.09); 65 to 74 years, 0.91 (95% CI, 0.88-0.95); and 75 years or older, 0.81 (95% CI, 0.79-0.83). The 3-way interaction (sex, age, and chest pain) on mortality was significant (P < .001). CONCLUSION In this registry of patients hospitalized with MI, women were more likely than men to present without chest pain and had higher mortality than men within the same age group, but sex differences in clinical presentation without chest pain and in mortality were attenuated with increasing age.

Use of Reperfusion Therapy for Acute Myocardial Infarction in the United States Data From the National Registry of Myocardial Infarction 2

BACKGROUND There is clear evidence that reperfusion therapy improves survival in selected patients with an acute myocardial infarction. However, several studies have suggested that many patients with an acute myocardial infarction do not receive this therapy. Whether this underutilization occurs in patients appropriate for such therapy remains unclear. METHODS AND RESULTS We examined the use of reperfusion therapy in patients with an acute myocardial infarction hospitalized at 1470 hospitals participating in the National Registry of Myocardial Infarction 2. We identified 84 663 patients who were eligible for reperfusion therapy as defined by diagnostic changes on the initial 12-lead ECG, presentation to the hospital within 6 hours from symptom onset, and no contraindications to thrombolytic therapy. Twenty-four percent of these eligible patients did not receive any form of reperfusion therapy (7.5% of all patients). When multivariate analyses were used, left bundle-branch block (odds ratio [OR]=0.22; 95% CI=0.20 to 0.24), lack of chest pain at presentation (OR=0.22; 95% CI=0.21 to 0.24), age >75 years (OR=0.40, 95% CI=0.36 to 0.43), female sex (OR=0.88, 95% CI=0.83 to 0.92), and various preexisting cardiovascular conditions were independent predictors that the patient would not receive reperfusion therapy. CONCLUSIONS Reperfusion therapy may be underutilized in the United States. Increased use of reperfusion therapy could potentially reduce the unnecessarily high mortality rates observed in women, the elderly, and other patient groups with the highest risk of death from an acute myocardial infarction.

The prehospital electrocardiogram in acute myocardial infarction : Is its full potential being realized?

OBJECTIVES This study sought to examine the management and subsequent outcomes of patients with a prehospital electrocardiogram (ECG) in a large, voluntary registry of myocardial infarction. BACKGROUND The prehospital ECG has been proposed as a means of rapidly identifying patients with acute myocardial infarction who might be eligible for reperfusion therapy. METHODS The characteristics and outcomes of patients with a prehospital ECG were compared with those without a prehospital ECG in the National Registry of Myocardial Infarction 2 data base. Included in the analysis were those patients who presented to the hospital within 12 h of an acute myocardial infarction. Excluded were patients with an in-hospital infarction, transferred-in referrals and self-transported patients. RESULTS Prehospital ECGs were obtained in 3,768 (5%) of 66,995 National Registry of Myocardial Infarction 2 patients meeting study criteria. Median time from myocardial infarction symptom onset until hospital arrival was longer among those having a prehospital ECG (152 vs. 91 min, p < 0.001). However, once in the hospital, the prehospital ECG group experienced a shorter median time to the initiation of either thrombolysis (30 vs. 40 min, p < 0.001) or primary angioplasty (92 vs. 115 min, p < 0.001). The prehospital ECG group was more likely to receive thrombolytic therapy (43% vs. 37%, p < 0.001) and to undergo primary angioplasty (11% vs. 7%, p < 0.001). Also, the prehospital ECG group was more likely to undergo coronary arteriography (55% vs. 40%, p < 0.001), angioplasty (24% vs. 16%, p < 0.001) or bypass surgery (10% vs. 6%, p < 0.001). The in-hospital mortality rate was 8% in patients with a prehospital ECG and 12% in those without a prehospital ECG (p < 0.001). After adjusting for baseline covariates utilizing multiple logistic regression analysis, this mortality difference remained statistically significant (odds ratio 0.83, 95% confidence interval 0.71 to 0.96, p = 0.01). CONCLUSIONS The prehospital ECG is infrequently utilized for diagnosing myocardial infarction, and among patients with a prehospital ECG, is associated with a longer time from symptom onset to hospital arrival. Despite these shortcomings, the prehospital ECG is a test that may potentially influence the management of patients with acute myocardial infarction through wider, faster in-hospital utilization of reperfusion strategies and greater usage of invasive procedures, factors that may possibly reduce shortterm mortality. Efforts to implement the prehospital ECG more widely and more rapidly may be indicated.

Relation of race and sex to the use of reperfusion therapy in Medicare beneficiaries with acute myocardial infarction.

BACKGROUND There are few reports describing the combined influence of the race and sex of a patient on the use of reperfusion therapy for acute myocardial infarction. METHODS To determine the relation of race and sex to the receipt of reperfusion therapy for myocardial infarction in the United States, we reviewed the medical records of 234,769 Medicare patients with myocardial infarction. From these records we identified 26,575 white or black patients who met strict eligibility criteria for reperfusion therapy. We then performed bivariate and multivariate analyses of prevalence ratios to determine predictors of the use of reperfusion therapy in four subgroups of patients categorized according to race and sex: white men, white women, black men, and black women. RESULTS Among eligible patients, white men received reperfusion therapy with the highest frequency (59 percent), followed by white women (56 percent), black men (50 percent), and black women (44 percent). After adjustment for differences in demographic and clinical characteristics, white women were as likely as white men to receive reperfusion therapy (prevalence ratio, 1.00; 95 percent confidence interval, 0.98 to 1.03). Likewise, black women were as likely as black men to receive reperfusion therapy (prevalence ratio, 1.00; 95 percent confidence interval, 0.89 to 1.13). However, black women were significantly less likely to receive reperfusion therapy than white men (prevalence ratio, 0.90; 95 percent confidence interval, 0.82 to 0.98), as were black men (prevalence ratio, 0.85; 95 percent confidence interval, 0.78 to 0.93). CONCLUSIONS After adjustment for differences in clinical and demographic characteristics and clinical presentation, differences according to sex in the use of reperfusion therapy are minimal. However, blacks, regardless of sex, are significantly less likely than whites to receive this potentially lifesaving therapy.

Trends in quality of care for patients with acute myocardial infarction in the National Registry of Myocardial Infarction from 1990 to 2006

BACKGROUND Trends in the use of guideline-based treatment for acute myocardial infarction (AMI) as well as its association with patient outcomes have not been summarized in a large, longitudinal study. Furthermore, it is unknown whether gender-, race-, and age-based care disparities have narrowed over time. METHODS AND RESULTS Using the National Registry of Myocardial Infarction database, we analyzed 2,515,106 patients with AMI admitted to 2,157 US hospitals between July 1990 and December 2006 to examine trends overall and in select subgroups of guideline-based admission, procedural, and discharge therapy use. The contribution of temporal improvements in acute care therapies to declines in in-hospital mortality was examined using logistic regression analysis. From 1990 to 2006, the use of all acute guideline-recommended therapies administered rose significantly for patients with ST-segment elevation myocardial infarction and patients with non-ST-segment myocardial infarction but remained below 90% for most therapies. Cardiac catheterization and percutaneous coronary intervention use increased in patients with ST-segment elevation myocardial infarction and patients with non-ST-segment myocardial infarction, whereas coronary bypass surgery use declined in both groups. Despite overall care improvements, women, blacks, and patients > or =75 years old were significantly less likely to receive revascularization or discharge lipid-lowering therapy relative to their counterparts. Temporal improvements in acute therapies may account for up to 37% of the annual decline in risk for in-hospital AMI mortality. CONCLUSION Adherence to American Heart Association/American College of Cardiology practice guidelines has improved care of patients with AMI and is associated with significant reductions in in-hospital mortality rates. However, persistent gaps in overall care as well as care disparities remain and suggest the need for ongoing quality improvement efforts.

Sex differences in mortality after acute myocardial infarction: changes from 1994 to 2006.

BACKGROUND Previous studies have shown that women younger than 55 years have higher hospital mortality rates after acute myocardial infarction (MI) than age-matched men. We examined whether such mortality differences have decreased in recent years. METHODS We investigated temporal trends in the hospital case-fatality rates of MI by sex and age from June 1, 1994, through December 31, 2006. The study population included 916,380 patients from the National Registry of Myocardial Infarction with a confirmed diagnosis of MI. RESULTS In-hospital mortality decreased markedly between 1994 and 2006 in all patients but more so in women than men. The mortality reduction in 2006 relative to 1994 was largest in women younger than 55 years (52.9%) and lowest in men younger than 55 years (33.3%). In patients younger than 55 years, the absolute decrease in mortality was 3 times larger in women than men (2.7% vs 0.9%). As a result, the excess mortality in younger women (<55 years) compared with men was less pronounced in 2004-2006 (unadjusted odds ratio, 1.32; 95% confidence interval, 1.07-1.67) than it was in 1994-1995 (unadjusted odds ratio, 1.93; 95% confidence interval, 1.67-2.24). The sex difference in mortality decrease was lower in older patients (P = .004 for the interaction among sex, age, and year). Changes in comorbidity and clinical severity features at admission accounted for more than 90% of these mortality trends. CONCLUSIONS In recent years, women, particularly younger ones, experienced larger improvements in hospital mortality after MI than men. The narrowing of the mortality gap between younger women and men is largely attributable to temporal changes in risk profiles.

Early Use of Glycoprotein IIb/IIIa Inhibitors in Non-ST-Elevation Acute Myocardial Infarction Observations From the National Registry of Myocardial Infarction 4

OBJECTIVES We sought to identify patient and hospital features associated with early glycoprotein (GP) IIb/IIIa inhibitor therapy for non-ST-elevation (NSTE) myocardial infarction (MI) and to relate this treatment to in-hospital outcomes. BACKGROUND Glycoprotein IIb/IIIa inhibitors have improved outcomes in randomized trials of NSTE MI, leading national treatment guidelines to recommend their use. Their actual use, safety, and effectiveness have not been well characterized beyond trial populations. METHODS We studied 60,770 patients with NSTE MI treated between July 2000 and July 2001 at 1,189 hospitals in a U.S. registry. Using logistic regression, we identified patient and hospital features associated with GP IIb/IIIa inhibition within 24 h after presentation. We also compared outcomes by early treatment versus no treatment after adjusting for patient and hospital characteristics and treatment propensity. RESULTS Only 25% of eligible patients received early GP IIb/IIIa therapy. Elderly patients, women, minority patients, and those without private insurance received such therapy less often than their counterparts. Treated patients had lower unadjusted in-hospital mortality (3.3% vs. 9.6%, p < 0.0001) remaining significantly lower after adjustment for patient risk, treatment propensity, and hospital characteristics (adjusted odds ratio, 0.88; 95% confidence interval, 0.79 to 0.97). Hospitals that adopted early GP IIb/IIIa inhibition more rapidly also had lower adjusted mortality rates than those slower to adopt such therapy. CONCLUSIONS Glycoprotein IIb/IIIa inhibitor therapy appears to be underused in early management of NSTE MI patients. Because this therapy is associated with better outcomes, it represents a target for quality improvement.

Relation Between Hospital Intra-Aortic Balloon Counterpulsation Volume and Mortality in Acute Myocardial Infarction Complicated by Cardiogenic Shock

Background—Increasing evidence suggests an inverse relationship between outcome and the total number of invasive cardiac procedures performed at a given hospital. The purpose of the present study was to determine if a similar relationship exists between the number of intra-aortic balloon counterpulsation (IABP) procedures performed at a given hospital per year and the in-hospital mortality rate of patients with acute myocardial infarction complicated by cardiogenic shock. Methods and Results—We analyzed data of 12 730 patients at 750 hospitals enrolled in the National Registry of Myocardial Infarction 2 from 1994 to 1998. The hospitals were divided into tertiles (low–, intermediate–, and high–IABP volume hospitals) according to the number of IABPs performed at the given hospital per year. The median number of IABPs performed per hospital per year was 3.4, 12.7, and 37.4 IABPs at low-, intermediate-, and high-volume hospitals, respectively. Of those patients who underwent IABP, there were only minor differences in baseline patient characteristics between the 3 groups. Crude mortality rate decreased with increasing IABP volume: 65.4%, lowest volume tertile; 54.1%, intermediate volume tertile; and 50.6%, highest volume tertile (P for trend <0.001). This mortality difference represented 150 fewer deaths per 1000 patients treated at the high IABP hospitals. In the multivariate analysis, high hospital IABP volume for patients with acute myocardial infarction was associated with lower mortality (OR=0.71, 95% CI=0.56 to 0.90), independent of baseline patient characteristics, hospital factors, treatment, and procedures such as PTCA. Conclusions—Among the myocardial infarction patients with cardiogenic shock who underwent IABP placement, mortality rate was significantly lower at high–IABP volume hospitals compared with low–IABP volume hospitals.

The joint contribution of sex, age and type of myocardial infarction on hospital mortality following acute myocardial infarction

Objective: Younger, but not older, women have a higher mortality than men of similar age after a myocardial infarction (MI). We sought to determine whether this relationship is true for both ST elevation MI (STEMI) and non-ST elevation MI (NSTEMI). Design: Retrospective cohort study. Setting: 1057 USA hospitals participant in the National Registry of Myocardial Infarction between 2000 and 2006. Patients: 126 172 STEMI and 235 257 NSTEMI patients. Main outcome measure: Hospital death. Results: For both STEMI and NSTEMI, the younger the patient’s age, the greater the excess mortality risk for women compared with men, while older women fared similarly (STEMI) or better (NSTEMI) than men (p<0.0001 for the age–sex interaction). In STEMI, the unadjusted women-to-men RR was 1.68 (95% CI 1.41 to 2.01), 1.78 (1.59 to 1.99), 1.45 (1.34 to 1.57), 1.08 (1.02 to 1.14) and 1.03 (0.98 to 1.07) for age <50 years, age 50–59, age 60–69, age 70–79 and age 80–89, respectively. For NSTEMI, corresponding unadjusted RRs were 1.56 (1.31 to 1.85), 1.42 (1.27 to 1.58), 1.17 (1.09 to 1.25), 0.92 (0.88 to 0.96) and 0.86 (0.83 to 0.89). After adjusting for risk status, the excess risk for younger women compared with men decreased to approximately 15–20%, while a better survival of older NSTEMI women compared with men persisted. Conclusions: Sex-related differences in short-term mortality are age-dependent in both STEMI and NSTEMI patients.