Prevalence, clinical characteristics, and mortality among patients with myocardial infarction presenting without chest pain

CONTEXT

Although chest pain is widely considered a key symptom in the diagnosis of myocardial infarction (MI), not all patients with MI present with chest pain. The extent to which this phenomenon occurs is largely unknown.

OBJECTIVES

To determine the frequency with which patients with MI present without chest pain and to examine their subsequent management and outcome.

DESIGN

Prospective observational study.

SETTING AND PATIENTS

A total of 434,877 patients with confirmed MI enrolled June 1994 to March 1998 in the National Registry of Myocardial Infarction 2, which includes 1674 hospitals in the United States.

MAIN OUTCOME MEASURES

Prevalence of presentation without chest pain; clinical characteristics, treatment, and mortality among MI patients without chest pain vs those with chest pain.

RESULTS

Of all patients diagnosed as having MI, 142,445 (33%) did not have chest pain on presentation to the hospital. This group of MI patients was, on average, 7 years older than those with chest pain (74.2 vs 66.9 years), with a higher proportion of women (49.0% vs 38.0%) and patients with diabetes mellitus (32.6% vs 25. 4%) or prior heart failure (26.4% vs 12.3%). Also, MI patients without chest pain had a longer delay before hospital presentation (mean, 7.9 vs 5.3 hours), were less likely to be diagnosed as having confirmed MI at the time of admission (22.2% vs 50.3%), and were less likely to receive thrombolysis or primary angioplasty (25.3% vs 74.0%), aspirin (60.4% vs 84.5%), beta-blockers (28.0% vs 48.0%), or heparin (53.4% vs 83.2%). Myocardial infarction patients without chest pain had a 23.3% in-hospital mortality rate compared with 9.3% among patients with chest pain (adjusted odds ratio for mortality, 2. 21 [95% confidence interval, 2.17-2.26]).

CONCLUSIONS

Our results suggest that patients without chest pain on presentation represent a large segment of the MI population and are at increased risk for delays in seeking medical attention, less aggressive treatments, and in-hospital mortality. JAMA. 2000;283:3223-3229

Temporal trends in the treatment of over 1.5 million patients with myocardial infarction in the US from 1990 through 1999: the National Registry of Myocardial Infarction 1, 2 and 3

OBJECTIVES

We sought to determine trends in the treatment of myocardial infarction from 1990 through 1999 in the U.S. and to relate these trends to current guidelines.

BACKGROUND

Limited data are available to show how recent clinical trials and clinical guidelines have impacted treatment of myocardial infarction.

METHODS

Temporal trends in myocardial infarction treatment and outcome were assessed by using data from 1,514,292 patients in the National Registry of Myocardial Infarction (NRMI) 1, 2 and 3 from 1990 through 1999.

RESULTS

During this interval, the use of intravenous thrombolytic therapy declined from 34.3% to 20.8%, but the use of primary angioplasty increased from 2.4% to 7.3% (both p = 0.0001). The median "door-to-drug" time among thrombolytic therapy recipients fell from 61.8 to 37.8 min (p = 0.0001), primarily owing to shorter "door-to-data" and "data-to-decision" times. The prevalence of non-Q wave infarctions increased from 45% in 1994 to 63% in 1999 (p = 0.0001). From 1994 through 1999, there was increased usage of beta-blockers, aspirin and angiotensin-converting inhibitors, both during the first 24 h after admission and on hospital discharge (all p = 0.0001). Between 1990 and 1999, the median duration of hospital stay fell from 8.3 to 4.3 days, and hospital mortality declined from 11.2% to 9.4% (both p = 0.0001).

CONCLUSIONS

The NRMI data from 1990 through 1999 demonstrate that the recommendations of recent clinical trials and published guidelines are being implemented, resulting in more rapid administration of intravenous thrombolytic therapy, increasing use of primary angioplasty and more frequent use of adjunctive therapies known to reduce mortality, and may be contributing to the higher prevalence of non-Q wave infarctions, shorter hospital stays and lower hospital mortality.

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.

Relation between hospital primary angioplasty volume and mortality for patients with acute MI treated with primary angioplasty vs thrombolytic therapy

CONTEXT

Institutional experience with primary angioplasty has been suggested as a factor in selecting a reperfusion strategy for patients with acute myocardial infarction (AMI). However, no large studies have directly compared outcomes of primary angioplasty vs thrombolytic therapy as a function of institutional experience.

OBJECTIVE

To compare outcomes among patients with AMI who were treated with primary angioplasty vs thrombolytic therapy at hospitals with different volumes of primary angioplasty.

DESIGN

Retrospective cohort.

SETTING

A total of 446 acute care hospitals with 112 classified as low volume (</=16 procedures), 223 as intermediate volume (17-48 procedures), and 111 as high volume (>/=49 procedures) based on their annual primary angioplasty volume.

PATIENTS

A total of 62 299 patients with AMI treated with primary angioplasty or thrombolytic therapy from June 1, 1994, through July 31, 1999.

MAIN OUTCOME MEASURE

In-hospital mortality.

RESULTS

Mortality was lower among patients who received primary angioplasty compared with those who received thrombolysis at hospitals with intermediate volumes (4.5% vs 5.9%; P<.001) and high volumes (3.4% vs 5.4%; P<.001) of primary angioplasty. At low-volume hospitals, there was no significant difference in mortality between patients treated with primary angioplasty vs those treated with thrombolysis (6.2% vs 5.9%; P =.58). Adjusting for differences in demographic, medical history, clinical presentation, treatment, and hospital characteristics did not significantly alter these findings.

CONCLUSIONS

In this study, patients with AMI treated at hospitals with high or intermediate volumes of primary angioplasty had lower mortality with primary angioplasty than with thrombolysis, whereas patients with AMI treated at hospitals with low angioplasty volumes had similar mortality outcomes with primary angioplasty or thrombolysis.

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.

A comparison of the national registry of myocardial infarction 2 with the cooperative cardiovascular project

OBJECTIVES

This study was performed to evaluate whether or not the simpler case identification and data abstraction processes used in National Registry of Myocardial Infarction two (NRMI 2) are comparable with the more rigorous processes utilized in the Cooperative Cardiovascular Project (CCP).

BACKGROUND

The increased demand for quality of care and outcomes data in hospitalized patients has resulted in a proliferation of databases of varying quality. For patients admitted with myocardial infarction, there are two national databases that attempt to capture critical process and outcome data using different case identification and abstraction processes.

METHODS

We compared case ascertainment and data elements collected in Medicare-eligible patients included in the industry-sponsored NRMI 2 with Medicare enrollees included in the Health Care Financing Administration-sponsored CCP who were admitted during identical enrollment periods. Internal and external validity of NRMI 2 was defined using the CCP as the "gold standard."

RESULTS

Demographic and procedure use data obtained independently in each database were nearly identical. There was a tendency for NRMI 2 to identify past medical histories such as prior infarct (29% vs. 31%, p < 0.001) or heart failure (21% vs. 25%, p < 0.001) less frequently than the CCP. Hospital mortality was calculated to be higher in NRMI 2 (19.7% vs. 18.1%, p < 0.001) due mostly to the inclusion of noninsured patients 65 years and older in NRMI 2.

CONCLUSIONS

We conclude that the simpler case ascertainment and data collection strategies employed by NRMI 2 result in process and outcome measures that are comparable to the more rigorous methods utilized by the CCP. Outcomes that are more difficult to measure from retrospective chart review such as stroke and recurrent myocardial infarction must be interpreted cautiously.

Hormone therapy and in-hospital survival after myocardial infarction in postmenopausal women

BACKGROUND

Although postmenopausal hormone therapy (HRT) commonly is used in hope of preventing coronary heart disease, the effect of HRT on case fatality of myocardial infarction has never been studied. We evaluated HRT as a predictor of survival after MI in postmenopausal women.

METHODS AND RESULTS

The present study was performed with 114 724 women of age >/=55 years with confirmed myocardial infarction who presented between April 1998 and January 2000 to 1 of 1674 hospitals participating in the National Registry of Myocardial Infarction-3. Presenting characteristics, treatment, and clinical outcome data were obtained by chart review. At time of hospitalization, 7353 (6.4%) women reported current use of HRT, defined as use of estrogen, progestin, or estrogen/progestin for reasons other than contraception. Unadjusted mortality was 7.4% in users of HRT and 16.2% in nonusers (odds ratio 0.41, 95% confidence interval 0.36 to 0.43). After adjustments were made for prior medical history, clinical characteristics, treatments received in-hospital, and likelihood of receiving HRT, HRT remained associated with an improved rate of survival (odds ratio 0.65, 95% confidence interval 0.59 to 0.72). Significant association of HRT with decreased mortality after myocardial infarction was observed in all age strata.

CONCLUSIONS

Postmenopausal HRT appears to be associated with reduced mortality after myocardial infarction. This finding could be caused by therapeutic effect of HRT, selection and adherence bias, or some combination of both.

Prognostic value of a normal or nonspecific initial electrocardiogram in acute myocardial infarction

CONTEXT

Although previous studies have suggested that normal and nonspecific initial electrocardiograms (ECGs) are associated with a favorable prognosis for patients with acute myocardial infarction (AMI), their independent predictive value for mortality has not been examined.

OBJECTIVE

To compare in-hospital mortality among patients with AMI who have normal or nonspecific initial ECGs with that of patients who have diagnostic ECGs.

DESIGN, SETTING, AND PATIENTS

Multihospital observational study in which 391 208 patients with AMI met the study criteria between June 1994 and June 2000 and had ECGs that were normal (n = 30 759), nonspecific (n = 137 574), or diagnostic (n = 222 875; defined as ST-segment elevation or depression and/or left bundle-branch block). A logistic regression model was constructed using a propensity score for ECG findings and data on demographics, medical history, diagnostic procedures, and therapy to determine the independent prognostic value of a normal or nonspecific initial ECG.

MAIN OUTCOME MEASURES

In-hospital mortality; composite outcome of in-hospital death and life-threatening adverse events.

RESULTS

In-hospital mortality rates were 5.7%, 8.7%, and 11.5% while the rates of the composite of mortality and life-threatening adverse events were 19.2%, 27.5%, and 34.9% for the normal, nonspecific, and diagnostic ECG groups, respectively. After adjusting for other predictor variables, the odds of mortality for the normal ECG group was 0.59 (95% confidence interval [CI], 0.56-0.63; P<.001) and for the nonspecific group was 0.70 (95% CI, 0.68-0.72; P<.001), compared with the diagnostic ECG group.

CONCLUSION

In this large cohort of patients with AMI, patients presenting with normal or nonspecific ECGs did have lower in-hospital mortality rates than those of patients with diagnostic ECGs, yet the absolute rates were still unexpectedly high.

Treatment and outcomes of left bundle-branch block patients with myocardial infarction who present without chest pain. National Registry of Myocardial Infarction 2 Investigators

OBJECTIVES

We sought to determine the importance of chest pain on presentation as a predictor of in-hospital treatment and mortality in myocardial infarction (MI) patients with left bundle-branch block (LBBB).

BACKGROUND

Left bundle-branch block patients have a high mortality after MI but are unlikely to receive reperfusion therapy despite evidence from clinical trials demonstrating the efficacy of thrombolytic therapy. Nearly half of MI patients with LBBB present without chest pain.

METHODS

We studied the clinical features, treatment and in-hospital survival of 29,585 patients with LBBB enrolled in the National Registry of MI 2 June 1994 through March 1998). Multivariate logistic regression was used to assess the independent effect of chest pain on reperfusion decisions and in-hospital mortality.

RESULTS

Left bundle-branch block patients with chest pain were greater than five-fold more likely to receive reperfusion therapy (13.6% vs. 2.6%) than LBBB patients without chest pain; they were also more likely to receive aspirin, beta-adrenergic blocking agents, heparin and nitrates (all p < 0.0001). Unadjusted in-hospital mortality was 18% in patients with chest pain and 27% in patients without chest pain. Adjusting for patient characteristics reduced the odds ratio associated with the absence of chest pain from 1.47 (95% confidence interval: 1.41 to 1.54) to 1.21 (95% confidence interval: 1.12 to 1.30). The remainder of the mortality difference was caused by the undertreatment of patients without chest pain, particularly the low utilization of aspirin and beta-blockers.

CONCLUSIONS

Left bundle-branch block patients with MI who present without chest pain are less likely to receive optimal therapy and are at increased risk of death. Prompt recognition and treatment of this high-risk subgroup should improve survival.

Hormone therapy and the risk of stroke after acute myocardial infarction in postmenopausal women

OBJECTIVES

We examined the association of hormone therapy (HRT) with hemorrhagic and ischemic stroke among postmenopausal women with acute myocardial infarction (AMI).

BACKGROUND

Hemorrhagic and ischemic strokes are common complications of AMI, and women are at increased risk for hemorrhagic stroke after thrombolytic therapy. This risk may be related to female hormones.

METHODS

Using data from the National Registry of Myocardial Infarction-3, we studied 114,724 women age 55 years or older admitted to the hospital for AMI, of whom 7,353 reported HRT use on admission. We determined rates of in-hospital hemorrhagic and ischemic stroke stratified by HRT use and estimated the independent association of HRT with each stroke type using multivariable logistic regression.

RESULTS

The HRT users were younger than non-users, had fewer risk factors for stroke including diabetes and prior stroke, and received more pharmacologic and invasive therapy including cardiac catheterization. A total of 2,152 (1.9%) in-hospital strokes occurred, with 442 (0.4%) hemorrhagic, 1,017 (0.9%) ischemic and 693 (0.6%) unspecified. Among HRT users and non-users, the rates of hemorrhagic stroke (0.40% vs. 0.42%, p = 1.00) and ischemic stroke (0.80% vs. 0.96%, p = 0.11) were similar. Among 13,328 women who received thrombolytic therapy, the rate of hemorrhagic stroke was not significantly different for users and non-users (1.6% vs. 2.1%, p = 0.22). After adjustment for baseline and treatment differences, HRT was not associated with hemorrhagic (odds ratio [OR], 0.88; 95% confidence intervals [CI], 0.58 to 1.35) or ischemic stroke (OR, 0.89; CI, 0.66 to 1.18).

CONCLUSIONS

Acute myocardial infarction is a high-risk setting for stroke among postmenopausal women, but HRT does not appear to modify that risk. Clinicians should not alter their approach to thrombolytic therapy based on HRT use.

Age and the utilization of cardiac catheterization following uncomplicated first acute myocardial infarction treated with thrombolytic therapy (The Second National Registry of Myocardial Infarction [NRMI-2])

Considerable data indicates that patients <50 years of age have lower morbidity and mortality after acute myocardial infarction (AMI) than older patients. It has been demonstrated that use of routine cardiac catheterization and revascularization in younger patients with AMI and successful thrombolysis does not confer benefit compared with a more conservative approach. Despite this, it has been our impression that cardiac catheterization is frequently employed in younger patients with AMI. Patients with uncomplicated initial AMI treated with thrombolytic therapy in the Second National Registry of Myocardial Infarction (NRMI-2) between June 1994 and April 1998 were identified. Patients were categorized into 4 age strata for purposes of analysis. A total of 61,232 cases met our inclusion criteria. Cardiac catheterization was performed during hospitalization in 78% of patients after an uncomplicated initial AMI. Age was inversely associated with receipt of cardiac catheterization: 85% of those < or =49 years old underwent catheterization compared with 63% of those > or =70 years old. Regression analysis revealed that use of catheterization was 2.9 times greater (95% confidence intervals 2.7 to 3.2) in patients < or =49 years old compared with those > or =70 years old. Geographic location and payor status also strongly influenced utilization of this procedure. In conclusion, routine coronary angiography after uncomplicated AMI is extensively utilized in all age groups, particularly in those <50 years of age. The efficacy and cost effectiveness of this strategy in these patients has not yet been determined in clinical trials.

Resurgence of congenital rubella syndrome in the 1990s. Report on missed opportunities and failed prevention policies among women of childbearing age

OBJECTIVE

To assess previous missed opportunities for rubella screening and vaccination of women delivering infants with congenital rubella syndrome and to discuss prevention strategies.

DESIGN

Descriptive analysis of data collected through interviews and review of medical records.

POPULATION STUDIED

Twenty-one women who delivered infants with congenital rubella syndrome in four Southern California counties from January 1, 1990, through January 8, 1991.

RESULTS

Twelve (57%) of the women had a total of 22 known missed opportunities for rubella screening or vaccination. Of the 22 missed opportunities, three (14%) were missed screenings at the time of marriage, two (9%) were missed screenings during previous pregnancies, five (23%) were missed screenings during induced abortions, and 12 (55%) were missed opportunities for vaccination postpartum or after induced abortions. Nine (43%) of the women had no known missed opportunities for rubella screening or vaccination. Of 12 women educated in California, only four (33%) were subject to the 1982 California school rubella immunization requirement.

CONCLUSIONS

Congenital rubella syndrome could have been prevented in more than half of the infants born to these women if missed opportunities for rubella testing and/or vaccination had not occurred. Because premarital rubella testing and school immunization requirements do not ensure that all women of childbearing age are immune to rubella, physicians and hospitals should establish procedures for postpartum rubella vaccination of susceptible women. Family planning and abortion clinics should implement routine rubella testing and follow-up vaccination of susceptible women.

Measles reporting completeness during a community-wide epidemic in inner-city Los Angeles

A study was undertaken to determine the extent of measles underreporting among preschool-age children. In two community surveys conducted in inner-city Los Angeles during 1990 and 1991, respondents were asked whether preschool-age children in their households had ever been ill with measles. Information about measles episodes was obtained and medical records were reviewed, when available. A probable measles case was defined as having 3 or more days of rash with fever of 38.3 degrees centigrade or greater, and either cough, coryza, or conjunctivitis. To determine the proportion of cases reported, probable measles cases identified were matched with measles cases reported to the Los Angeles County Department of Health Services. Of the 947 children ages 6 weeks through 59 months included in the surveys, 35 children had experienced an illness episode which met the probable measles case definition. Ten (29 percent) of the 35 probable measles cases were reported to the health department. Hospitals reported 9 (69 percent) of 13 probable measles cases evaluated while private physicians' offices reported 0 (0 percent) of 12 evaluated (Fisher's exact test, P < 0.001), although 5 children were seen by private physicians before rash onset. Reporting was more complete for cases occurring during 1990 and 1991 (33 percent) than from 1987 through 1989 (18 percent). The hospitalization rate for preschool-age children with probable measles cases in the catchment area was estimated to be 8 percent (95 percent confidence interval = 0 to 18 percent). Although measles is a serious communicable disease which is almost completely preventable, cases of it among preschool-age children in this high incidence area were substantially underreported,especially by private physicians. Due to reporting bias, reported measles cases were representative of more severe cases than all the cases that occurred.

Measles in pregnancy: a descriptive study of 58 cases

OBJECTIVE

To describe the effects of measles in pregnancy using a large case series.

METHODS

Pregnant women with measles were identified by county health department records, and their hospital and clinic records were reviewed. When available, records for the infants of case patients were also reviewed.

RESULTS

Fifty-eight pregnant women with measles were identified. Thirty-five (60%) were hospitalized for measles, 15 (26%) were diagnosed with pneumonia, and two (3%) died of measles complications. Excluding three induced abortions, 18 pregnancies (31%) ended prematurely; five were spontaneous abortions and 13 were preterm deliveries. All but two of the 18 pregnancies that terminated early did so within 14 days of rash onset. Two term infants were born with minor congenital anomalies, but their mothers had measles late in the third trimester. No newborns were diagnosed with congenital measles.

CONCLUSIONS

The incidence of death and other complications from measles during pregnancy may be higher than expected for age-comparable, nonpregnant women. Measles in pregnancy may lead to high rates of fetal loss and prematurity, especially in the first 2 weeks after the onset of rash.