Paul D. Frederick

Hospital delays in reperfusion for ST-elevation myocardial infarction: implications when selecting a reperfusion strategy.

Background— It has been suggested that the survival benefit associated with primary percutaneous coronary intervention (PPCI) in ST-segment elevation myocardial infarction may be attenuated if door-to-balloon (DB) time is delayed by >1 hour beyond door-to-needle (DN) times for fibrinolytic therapy. Whereas DB times are rapid in randomized trials, they are often prolonged in routine practice. We hypothesized that in clinical practice, longer DB-DN times would be associated with higher mortality rates and reduced PPCI survival advantage. We also hypothesized that in addition to PPCI delays, patient risk factors would significantly modulate the relative survival advantage of PPCI over fibrinolysis. Methods and Results— DB-DN times were calculated by subtracting median DN time from median DB time at a hospital using data from 192 509 patients at 645 National Registry of Myocardial Infarction hospitals. Hierarchical models that adjusted simultaneously for both patient-level risk factors and hospital-level covariates were used to evaluate the relationship between PCI-related delay, patient risk factors, and in-hospital mortality. Longer DB-DN times were associated with increased mortality (P<0.0001). The DB-DN time at which mortality rates with PPCI were no better than that of fibrinolysis varied considerably depending on patient age, symptom duration, and infarct location. Conclusions— As DB-DN times increase, the mortality advantage of PPCI over fibrinolysis declines, and this advantage varies considerably depending on patient characteristics. As indicated in the American College of Cardiology/American Heart Association guidelines, both the hospital-based PPCI-related delay (DB-DN time) and patient characteristics should be considered when a reperfusion strategy is selected.

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.

Predictors of door-to-balloon delay in primary angioplasty

In the treatment of acute myocardial infarction, delayed reperfusion therapy is associated with increased mortality. Predictors of delay have been described for fibrinolysis but not for primary percutaneous transluminal coronary angioplasty (pPTCA). Therefore, we studied 40,017 consecutive patients with acute myocardial infarction who underwent pPTCA in the National Registry of Myocardial Infarction between June 1994 and April 2000. Median door-to-balloon times were calculated, and factors independently associated with a delay of >120 minutes were determined by logistic regression. The median door-to-balloon time among all patients was 111 minutes (interquartile range 84 to 152). The proportion of patients with a delay of >2 hours was greater among those aged > or = 65 years (49% vs 41%), women (50% vs 42%), patients with contraindications to fibrinolysis (60% vs 41%), and those without chest pain on admission (61% vs 43%, all p <0.0001). Delay was also more common with transfer from another hospital (87% vs 38%), with presentation outside the hours of 8 A.M. to 4 P.M. (51% vs 38%), and in hospitals performing <49 pPTCAs/year (47% vs 41%, all p <0.0001). The strongest independent predictor of delay was hospital transfer, along with non-daytime presentation and low-volume centers. Older age, female sex, and non-white race were weaker predictors. Both patient and hospital factors are associated with delay in pPTCA after presentation. These findings may help design treatment algorithms to minimize delay, thus improving the survival benefit of pPTCA. These results may also help design trials of combination reperfusion strategies.

Clinical Characteristics of Dialysis Patients With Acute Myocardial Infarction in the United States A Collaborative Project of the United States Renal Data System and the National Registry of Myocardial Infarction

Background— Acute myocardial infarction (AMI) is catastrophic for dialysis patients. This study set out to determine the clinical characteristics of dialysis patients hospitalized for AMI in the United States. Methods and Results— This retrospective cohort study used data from the US Renal Data System (USRDS) database (n=1 285 177) and the third National Registry of Myocardial Infarction (NRMI 3) (n=537 444). AMI hospitalizations from April 1, 1998, through June 30, 2000, were identified using International Classification of Diseases, 9th edition, clinical modification, codes 410, 410.x, 410.x0, and 410.x1. The 9418 unique dialysis patients identified with AMI hospitalizations in the USRDS database were cross-matched with the NRMI registry, creating a cohort for analysis that consisted of 3049 matching patients. Clinical characteristics of dialysis and nondialysis (n=534 395) AMI patients were compared by use of the &khgr;2 test. Of clinical significance, 44.8% of dialysis patients were diagnosed as not having acute coronary syndrome on admission, versus 21.2% of nondialysis patients; 44.4% presented with chest pain, versus 68.3% of nondialysis patients; and 19.1% had ST elevation, versus 35.9% of nondialysis patients. Cardiac arrest was twice as frequent for dialysis patients (11.0% versus 5.0%), and in-hospital death was nearly so (21.3% versus 11.7%). In a logistic regression model, the odds ratio for in-hospital death for dialysis versus nondialysis patients was 1.498 (95% CI, 1.340 to 1.674). Conclusions— Dialysis patients hospitalized for AMI differ strikingly from nondialysis patients, which possibly explains their poor outcomes. Intensive efforts for early, accurate recognition of AMI in dialysis patients are warranted.

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.

Benefit of Transferring ST-Segment–Elevation Myocardial Infarction Patients for Percutaneous Coronary Intervention Compared With Administration of Onsite Fibrinolytic Declines as Delays Increase

Background— Although randomized trials suggest that transfer for primary percutaneous coronary intervention (X-PCI) in ST-segment–elevation myocardial infarction is superior to onsite fibrinolytic therapy (O-FT), the generalizability of these findings to routine clinical practice is unclear because door-to-balloon (XDB) times are rapid in randomized trials but are frequently prolonged in practice. We hypothesized that delays resulting from transfer would reduce the survival advantage of X-PCI compared with O-FT. Methods and Results— ST-segment–elevation myocardial infarction patients enrolled in the National Registry of Myocardial Infarction (NRMI) within 12 hours of pain onset were identified. Propensity matching of patients treated with X-PCI and O-FT was performed, and the effect of PCI-related delay on in-hospital mortality was assessed. PCI-related delay was calculated by subtracting the XDB from the door-to-needle time in each matched pair. Conditional logistic regression adjusted for patient and hospital variables identified the XDB door-to-needle time at which no mortality advantage for X-PCI over O-FT was present. Eighty-one percent of X-PCI patients were matched (n=9506) to O-FT patients (n=9506). In the matched cohort, X-PCI was performed with delays >90 minutes in 68%. Multivariable analysis found no mortality advantage for X-PCI over O-FT when XDB door-to-needle time exceeded ≈120 minutes. Conclusion— PCI-related delays are extensive among patients transferred for X-PCI and are associated with poorer outcomes. No differential excess in mortality was seen with X-PCI compared with O-FT even with long PCI-related delays, but as XDB door-to-needle time times increase, the mortality advantage for X-PCI over O-FT declines.

Number of Coronary Heart Disease Risk Factors and Mortality in Patients With First Myocardial Infarction

CONTEXT Few studies have examined the association between the number of coronary heart disease risk factors and outcomes of acute myocardial infarction in community practice. OBJECTIVE To determine the association between the number of coronary heart disease risk factors in patients with first myocardial infarction and hospital mortality. DESIGN Observational study from the National Registry of Myocardial Infarction, 1994-2006. PATIENTS We examined the presence and absence of 5 major traditional coronary heart disease risk factors (hypertension, smoking, dyslipidemia, diabetes, and family history of coronary heart disease) and hospital mortality among 542,008 patients with first myocardial infarction and without prior cardiovascular disease. MAIN OUTCOME MEASURE All-cause in-hospital mortality. RESULTS A majority (85.6%) of patients who presented with initial myocardial infarction had at least 1 of the 5 coronary heart disease risk factors, and 14.4% had none of the 5 risk factors. Age varied inversely with the number of coronary heart disease risk factors, from a mean age of 71.5 years with 0 risk factors to 56.7 years with 5 risk factors (P for trend < .001). The total number of in-hospital deaths for all causes was 50,788. Unadjusted in-hospital mortality rates were 14.9%, 10.9%, 7.9%, 5.3%, 4.2%, and 3.6% for patients with 0, 1, 2, 3, 4, and 5 risk factors, respectively. After adjusting for age and other clinical factors, there was an inverse association between the number of coronary heart disease risk factors and hospital mortality adjusted odds ratio (1.54; 95% CI, 1.23-1.94) among individuals with 0 vs 5 risk factors. This association was consistent among several age strata and important patient subgroups. CONCLUSION Among patients with incident acute myocardial infarction without prior cardiovascular disease, in-hospital mortality was inversely related to the number of coronary heart disease risk factors.

Hospital transfer of patients with acute myocardial infarction: the effects of age, race, and insurance type

BACKGROUND Many factors precipitate the transfer of patients hospitalized for acute myocardial infarction, including clinical status and the need for diagnostic testing and therapeutic interventions not available at the admitting hospital. The objectives of this study were to assess the frequency of transfer to another hospital and to determine whether nonmedical factors, such as age, sex, race, and insurance status, are associated with transfer. METHODS We conducted a prospective study of patients with acute myocardial infarction who were enrolled in the National Registry of Myocardial Infarction 2 from June 1994 through March 1998. The Registry involves 1674 hospitals in the United States. All patients survived to the time of hospital discharge or until transfer. Multivariable logistic regression models, with transfer as the outcome variable, were developed for the entire sample, as well as for subgroups determined by the interventional capabilities of the admitting hospital. RESULTS Of 537,283 patients with acute myocardial infarction, 152,310 (28%) were transferred to another hospital after admission. After adjustment for differences in clinical and hospital characteristics, factors that were most associated with a reduced odds of transfer included older age (odds ratio [OR] = 0.43; 95% confidence interval [CI]: 0.42 to 0.44 for those aged >75 vs. <65 years), African-American race (OR = 0.69; 95% CI: 0.67 to 0.71 for African Americans vs. whites), and Medicaid/self-pay insurance status (OR = 0.68; 95% CI: 0.66 to 0.70 for Medicaid/self-pay vs. commercial insurance). These effects were most apparent for patients admitted to hospitals without full invasive diagnostic and therapeutic capabilities, but persisted to some extent among those admitted to hospitals with full invasive services. CONCLUSION Our findings suggest that nonmedical factors, including age, race, and insurance type, affect decisions regarding the transfer of patients hospitalized with acute myocardial infarction. As only a minority of the nations hospitals offers a full range of cardiovascular diagnostic and therapeutic procedures, these findings reinforce ongoing concerns about disparities in access to health care services for some patients.

Differences in symptom presentation and hospital mortality according to type of acute myocardial infarction

BACKGROUND Chest pain/discomfort (CP) is the hallmark symptom of acute myocardial infarction (MI), but some patients with MI present without CP. We hypothesized that MI type (ST-segment elevation MI [STEMI] or non-STEMI [NSTEMI]) may be associated with the presence or absence of CP. METHODS We investigated the association between CP at presentation and MI type, hospital care, and mortality among 1,143,513 patients with MI in the National Registry of Myocardial Infarction (NRMI) from 1994 to 2006. RESULTS Overall, 43.6% of patients with NSTEMI and 27.1% of patients with STEMI presented without CP. For both MI type, patients without CP were older, were more frequently female, had more diabetes or history of heart failure, were more likely to delay hospital arrival, and were less likely to receive evidence-based medical therapies and invasive cardiac procedures. Multivariable analysis indicated that NSTEMI (vs STEMI) was the strongest predictor of atypical symptoms (adjusted odds ratio [95% CI], 1.93 [1.91-1.95]). Within the 4 CP/MI type categories, hospital mortality was highest for no CP/STEMI (27.8%), followed by no CP/NSTEMI (15.3%) and CP/STEMI (9.6%), and was lowest for CP/NSTEMI (5.4%). The adjusted odds ratio of mortality was 1.38 (1.35-1.41) for no CP (vs CP) in the STEMI group and 1.31 (1.28-1.34) in the NSTEMI group. CONCLUSIONS Hospitalized patients with NSTEMI were nearly 2-fold more likely to present without CP than patients with STEMI. Patients with MI without CP were less quickly diagnosed and treated and had higher adjusted odds of hospital mortality, regardless of whether they had ST-segment elevation.