Factors associated with rehospitalization in patients with acute myocardial infarction

Rehospitalization of patients surviving acute myocardial infarction is common, but why it occurs is not well documented. In Seattle area hospitals, rehospitalization was frequent, particularly for women and those with extensive cardiac histories.

Association of gender and survival in patients with acute myocardial infarction

BACKGROUND

During the last 5 years, many studies have produced conflicting results concerning the survival of women hospitalized with acute myocardial infarction (AMI).

OBJECTIVE

To determine if gender is associated with hospital mortality and long-term survival in individuals with AMI.

METHODS

This prospective study included 4255 consecutive women (34%) and 8076 (66%) men who developed AMI in 19 Seattle, Wash, area hospitals between January 1988 and June 1994. Key information was abstracted from hospital records and entered in the Myocardial Infarction Triage and Intervention registry database. In addition, data concerning survival and rehospitalization were obtained from the state of Washington and linked to the Myocardial Infarction Triage and Intervention registry.

RESULTS

In comparison with men, women were 8 years older, more often had history of congestive heart failure, hypertension, or diabetes mellitus, and less often had history of myocardial infarction or coronary surgery. During hospitalization, women were less likely to undergo coronary angiography, thrombolytic therapy, coronary angioplasty, or bypass surgery. After adjustment for covariates, women were 20% more likely to die in the hospital (odds ratio, 1.22; 95% confidence interval, 1.06-1.39), yet long-term survival was similar in the 2 groups (hazard ratio, 0.97; 95% confidence interval, 0.90-1.05). The use of thrombolytic therapy or revascularization during the index hospitalization did not change the association between gender and survival.

CONCLUSIONS

All things being equal, women with AMI were more likely to die in the hospital, yet survival after hospital discharge did not differ according to gender. Appropriate treatment to reduce hospital mortality in women is needed.

Absence of association between insurance copayments and delays in seeking emergency care among patients with myocardial infarction

BACKGROUND

The requirement of copayments for emergency care is thought to control costs by reducing "inappropriate" visits to the emergency department. However, requiring copayments may lead to adverse outcomes if patients delay seeking care for emergency conditions. To determine whether such requirements are associated with delays in seeking care, we examined the length of time from the onset of symptoms to arrival at the hospital among patients with myocardial infarction who did or did not have required insurance copayments.

METHODS

All patients were enrolled in a single health maintenance organization (HMO) and presented with myocardial infarction at 1 of 19 hospitals in King County, Washington, from 1989 through 1994. There were 602 patients whose health insurance required a copayment for emergency department care (range, $25 to $100) and 729 patients with no copayment requirement. Data on the time to presentation were obtained from a review of ambulance and hospital records.

RESULTS

The median length of time from the onset of symptoms to arrival at the hospital, as adjusted for age, sex, and race, was 135 minutes for the copayment group and 137 minutes for the group with no copayment (95 percent confidence interval for the difference, -19 to +16 minutes). There was no significant association between the presence or absence of a copayment requirement and the time to arrival at the hospital after adjustment for calendar year, income, educational level, cardiac history, or clinical symptoms. Since some patients may be unaware of their copayment requirement, we performed a subgroup analysis of data on patients who had a previous visit to the emergency department with the same copayment status - that is, of patients who were likely to know about their copayment. This analysis also showed no significant association between the requirement for a copayment and delays in seeking treatment.

CONCLUSIONS

For privately insured patients in this HMO, the requirement of modest, fixed copayments for emergency services did not lead to delays in seeking treatment for myocardial infarction.

Long-term implications of racial differences in the use of revascularization procedures (the Myocardial Infarction Triage and Intervention registry)

The purpose of this study was to determine if less intensive use of revascularization procedures in black patients influenced the long-term survival of patients hospitalized for acute myocardial infarction (AMI) in metropolitan Seattle. From January 1988 through June 1994, AMI developed in 420 (4%) black and 10,834 white patients before hospital discharge or death. Black patients were 6 years younger, more socioeconomically disadvantaged, and had more hypertension, diabetes, and less prior coronary surgery. Similar proportions of black and white patients received thrombolytic therapy or cardiac catheterization. However, during hospitalization, 18% of black patients underwent coronary angioplasty compared with 26% of white patients (p = 0.0004); coronary artery bypass surgery was also used less frequently in black patients (7% vs 12%, p = 0.002). Unadjusted 2-year survival was 79% for black patients and 77% for white patients (p = 0.12). After adjusting for age, clinical variables, and the use of cardiac catheterization, thrombolytic therapy, and revascularization, race was not associated with long-term survival (hazard ratio = 0.92, 95% confidence interval = 0.73 to 1.17). Despite the less intensive use of revascularization procedures in black patients in Seattle, long-term survival after AMI was similar in the two groups of patients.

Selection of thrombolytic therapy for individual patients: development of a clinical model. GUSTO-I Investigators

We developed a logistic regression model with data from the GUSTO-I trial to predict mortality rate differences in individual patients who received accelerated tissue plasminogen activator (TPA) versus streptokinase treatment for acute myocardial infarction. A nomogram was developed from a reduced version of this model that approximated the underlying risk of patients treated with streptokinase, and thus the benefit of TPA. The 30-day mortality rate with accelerated TPA was 0.063 versus 0.073 with streptokinase and subcutaneously administered heparin and 0.074 with streptokinase and intravenously administered heparin. No baseline patient characteristics were significantly associated with a different relative effect of TPA. Older patients and those with anterior infarction, higher Killip classification (except Killip class IV), lower blood pressure, and increased heart rate had the greatest absolute benefit with accelerated TPA. Patients with acute myocardial infarction who had more high-risk characteristics derived a greater absolute benefit from treatment with accelerated TPA versus streptokinase.

Long-term follow-up of gender-specific outcomes after thrombolytic therapy for acute myocardial infarction from the GUSTO-I trial. Global Utilization of Streptokinase and Tissue Plasminogen Activator for Occluded Coronary Arteries

Our objective was to assess gender differences in mortality 1 year after acute myocardial infarction (MI). The Global Utilization of Streptokinase and Tissue Plasminogen Activator for Occluded Coronary Arteries (GUSTO-I) trial database of 41,021 patients with suspected acute MI was used to generate 1-year Kaplan-Meier survival plots. Risk quartiles and mortality of women and men were compared. The unadjusted 1-year mortality rate for the initial GUSTO-I population and 30-day survivors demonstrates a large gender gap [odds ratio for all patients = 2.2, 95% confidence interval (CI), 2.0-2.3, p < 0.001]. For the initial population, when adjusted for age, the gender gap is still apparent (odds ratio = 1.4, 95%, CI = 1.3-1.5, p < 0.001) although no longer significant when adjusted using the 30-day survival model (odds ratio = 1.06, 95% CI = 0.97-1.15, p < 0.001). For the 30-day survivors, adjustment based on age alone explained the 1-year mortality difference (risk ratio = 0.96, 95% CI 0.85-1.07, p = 0.441). When the population was divided into expected risk quartiles, women were more likely to fall into the higher expected risk quartiles, even after adjusting for age. A gender gap after acute MI is apparent, nearly all of which occurs within the first 30 days. A substantial portion of the gender gap is explained by the increased age of women, and the rest of the gap may be attributed to differences in variables predictive of 30-day mortality. During 1-year follow-up, the late mortality of women is no greater than that of age-matched men.

The physician's role in minimizing prehospital delay in patients at high risk for acute myocardial infarction: recommendations from the National Heart Attack Alert Program. Working Group on Educational Strategies To Prevent Prehospital Delay in Patients at High Risk for Acute Myocardial Infarction

Physicians and other health care professionals play an important role in reducing the delay to treatment in patients who have an evolving acute myocardial infarction. A multidisciplinary working group has been convened by the National Heart Attack Alert Program (which is coordinated by the National Heart, Lung, and Blood Institute of the National Institutes of Health) to address this concern. The working group's recommendations target specific groups of patients: those who are known to have coronary heart disease, atherosclerotic disease of the aorta or peripheral arteries, or cerebrovascular disease. The risk for acute myocardial infarction or death in such patients is five to seven times greater than that in the general population. The working group recommends that these high-risk patients be clearly informed about symptoms that they might have during a coronary occlusion, steps that they should take, the importance of contacting emergency medical services, the need to report to an appropriate facility quickly, treatment options that are available if they present early, and rewards of early treatment in terms of improved quality of life. These instructions should be reviewed frequently and reinforced with appropriate written material, and patients should be encouraged to have a plan and to rehearse it periodically. Because of the important role of the bystander in increasing or decreasing delay to treatment, family members and significant others should be included in all instruction. Finally, physicians' offices and clinics should devise systems to quickly assess patients who telephone or present with symptoms of a possible acute myocardial infarction.

The prehospital electrocardiogram in acute myocardial infarction: is its full potential being realized? National Registry of Myocardial Infarction 2 Investigators

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.

Gender and acute myocardial infarction: is there a different response to thrombolysis?

OBJECTIVES

This study sought to 1) determine the effect of gender on early and late infarct-related artery patency and reocclusion after thrombolytic therapy for acute myocardial infarction; 2) examine the effect of gender on left ventricular function in response to injury/reperfusion; and 3) assess the independent contribution of gender to early (30-day) mortality after acute myocardial infarction.

BACKGROUND

Women have a higher mortality rate than men after myocardial infarction. However, the effect of gender on infarct-related coronary artery patency and left ventricular response to injury/reperfusion have not been fully defined in the thrombolytic era.

METHODS

Patency rates and global and regional left ventricular function were determined in patients at 90 min and 5 to 7 days after thrombolytic therapy for acute myocardial infarction. The effect of gender on infarct-related artery patency and left ventricular function was determined. Thirty-day mortality differences between women and men were compared.

RESULTS

Women were significantly older and had more hypertension, diabetes, hypercholesterolemia, heart failure and shock. They were less likely to have had a previous myocardial infarction, history of smoking or previous bypass surgery. Ninety-minute patency rates (Thrombolysis in Myocardial Infarction [TIMI] flow grade 3) in women and men were 39% and 38%, respectively (p = 0.5). Reocclusion rates were 8.7% in women versus 5.1% in men (p = 0.14). Women had more recurrent ischemia than men (21.4% vs. 17.0%, respectively, p = 0.01). Ninety-minute ejection fraction and regional ventricular function were clinically similar in women and men with TIMI 2 or 3 flow (ejection fraction [mean +/- SD]: 63.4 +/- 6% vs. 59.4 +/- 0.7%, p = 0.02; number of chords: 21.4 +/- 0.9 vs. 21.0 +/- 1.9, p = 0.7; SD/chord: -2.4 +/- 08 vs. -2.4 +/- 0.2, p = 0.9, respectively). No clinically significant differences in left ventricular function were noted at 5- to 7-day follow-up. Women had a greater hyperkinetic response than men in the noninfarct zone (SD/chord: 2.4 +/- 0.2 vs. 1.7 +/- 0.1, p = 0.005). The 30-day mortality rate was 13.1% in women versus 4.8% in men (p < or = 0.0001). After adjustment for other clinical and angiographic variables, gender remained an independent determinant of 30-day mortality.

CONCLUSIONS

Women do not differ significantly from men with regard to either early infarct-related artery patency rates or reocclusion after thrombolytic therapy or ventricular functional response to injury/reperfusion. Gender was an independent determinant of 30-day mortality after acute myocardial infarction.

Admission prediction of expected final myocardial infarct size using weighted ST-segment, Q wave, and T wave measurements

Formulas for predicting final acute myocardial infarction (MI) size from ST-segment deviation on an initial electrocardiogram were proposed by Aldrich et al. for anterior and inferior infarct locations. This study of 529 patients who did not receive thrombolytic therapy was performed to determine the effectiveness of the Aldrich formulas for predicting final QRS MI size; to propose new formulas for predicting final MI size using ST-segment deviation, Q wave, and T wave information in a development population of 322 patients; and to evaluate the new formulas in a randomly selected population of 207 patients. The Aldrich formulas achieved correlations with final infarct size of r = .40 for anterior and r = .43 for inferior MI locations in the present population which are weaker than those previously reported. Formulas that consider electrocardiographic parameters in addition to ST-segment deviation were proposed for both anterior and inferior final MI size. In the test set of 207 patients, these models explained 16.9% and 15.2% of the variation in final MI size for anterior and inferior locations respectively. They may prove useful in assessing the extent of myocardial salvage where interventions are to be tested.

The role of thrombolytic drugs in the management of myocardial infarction. Comparative clinical trials

Optimal thrombolytic therapy in acute myocardial infarction must aim to achieve early and complete reperfusion of the infarct related coronary artery. Establishment of normal coronary flow (Thrombolysis in Myocardial Infarction [TIMI] grade 3) is the key correlate of improved survival. Three large-scale clinical trials, the Reteplase Angiographic Phase II International Dose-finding Study (RAPID 1), the Reteplase vs Alteplase Patency Investigation During Acute Myocardial Infarction Study (RAPID 2), and the International Joint Comparison of Thrombolytics Study (INJECT), have evaluated the comparative efficacy and safety of reteplase, a new, rapid-acting thrombolytic agent that offers the practical clinical convenience of bolus dosing. RAPID 1 and 2 demonstrated that reteplase was associated with superior early coronary artery patency rates compared with alteplase, whether alteplase was infused over 3 h or over 90 min. Further, the TIMI 3 flow rates achieved in reteplase-treated patients at 60 min were comparable to those achieved at 90 min with the accelerated alteplase dosing regimen. The INJECT trial showed that reteplase resulted in comparable mortality and clinical benefits to those achieved with streptokinase. All three studies demonstrated that reteplase therapy was not associated with an increase in bleeding complications or other adverse clinical events. The simple double-bolus regimen of reteplase administration may permit earlier initiation of thrombolysis with fewer dosing errors than with continuous infusion regimens and thus afford a reduction in the morbidity and mortality risks in patients with acute myocardial infarction.

Characteristics, management, and outcome of patients with acute myocardial infarction treated with bypass surgery. Myocardial Infarction Triage and Intervention Investigators

BACKGROUND

Although multiple studies have addressed the efficacy of bypass surgery in patients with stable angina, there are relatively few studies that have evaluated the optimal timing, risk of hospital mortality, and long-term outcome for patients with bypass surgery performed in the setting of acute infarction.

METHODS AND RESULTS

With data collected from all admitted patients with acute myocardial infarction to 19 Seattle-area hospitals between 1988 and 1994, we studied the characteristics, hospital course, and long-term outcome in 1299 patients who underwent bypass surgery. There was no difference in hospital mortality in patients operated on during the first 24 hours after admission compared with those operated on later in the hospital course (8.3% versus 7.2%; P=.60). Factors that predicted hospital mortality in those who underwent bypass surgery included increased age, prior bypass surgery, infarct extension, and stroke. Long-term outcome in those who underwent bypass surgery was excellent, with low rates of subsequent coronary angiography (7.4% at 3 years) and coronary angioplasty (2.6% at 3 years). Three-year survival was better in bypass recipients than in those treated medically (83% versus 66%; P < .0001), and this difference remained after multivariate adjustment for baseline differences (hazard ratio, 0.68; 95% CI, 0.55 to 0.85).

CONCLUSIONS

Patients can be safely operated on early in the course of acute infarction, risk factors for hospital mortality are not substantially different from factors identified in the noninfarct setting, and bypass surgery in select patients after acute infarction is associated with low repeat procedure use and excellent long-term survival.

A comparison of thrombolytic therapy with primary coronary angioplasty for acute myocardial infarction. Myocardial Infarction Triage and Intervention Investigators

BACKGROUND

Several relatively small randomized trials have shown that primary angioplasty results in a better short-term outcome than thrombolytic therapy in patients with acute myocardial infarction. These results, however, have not been duplicated other than in investigational trials.

METHODS

We compared mortality during hospitalization and long-term mortality, as well as the use of resources, among 1050 patients in a primary-angioplasty group and 2095 patients in a thrombolytic-therapy group. Patients were selected from the Myocardial Infarction Triage and Intervention Project Registry cohort of 12,331 consecutive patients admitted with acute myocardial infarction to 19 Seattle hospitals between 1988 and 1994. Because of the potential for selection bias, several subgroup analyses were performed that included patients eligible for thrombolysis, high-risk patients, and patients in the primary-angioplasty group who were treated at hospitals with high volumes of angioplasty.

RESULTS

There was no significant difference in mortality during hospitalization or long-term follow-up between patients in the thrombolytic-therapy group and those in the primary-angioplasty group (mortality during hospitalization, 5.6 percent and 5.5 percent, respectively; P=0.93; adjusted hazard ratio for the risk of death within three years after primary angioplasty, 0.95; 95 percent confidence interval, 0.8 to 1.2). There was also no significant difference in mortality between high-risk subgroups of patients in the two treatment groups. The rates of procedures and costs were lower among patients in the thrombolytic-therapy group both at the time of hospital discharge and after three years of follow-up (30 percent fewer coronary angiograms, 15 percent fewer coronary angioplasties, and 13 percent lower costs after three years of follow-up).

CONCLUSIONS

In a community setting, we observed no benefit in terms of either mortality or the use of resources with a strategy of primary angioplasty rather than thrombolytic therapy in a large cohort of patients with acute myocardial infarction.

Determinants of the use of coronary angiography and revascularization after thrombolysis for acute myocardial infarction

BACKGROUND

Clinical trials and practice guidelines have identified clinical criteria for the use of coronary angiography and revascularization procedures after thrombolysis for acute myocardial infarction. The effect of these criteria on clinical practice has not been extensively evaluated.

METHODS

We used classification-and-regression-tree (CART) and logistic-regression models to study the patients in the first Global Utilization of Streptokinase and Tissue Plasminogen Activator for Occluded Coronary Arteries trial, to identify the variables that best predicted the use of angiography and revascularization procedures after thrombolysis.

RESULTS

Among the 21,772 U.S. patients in the trial, 71 percent underwent coronary angiography before discharge from the hospital. Of these, 58 percent underwent revascularization (73 percent receiving angioplasty). The CART model for the use of angiography showed that age was the variable most predictive of angiography; only 53 percent of patients at least 73 years of age underwent angiography, as compared with 76 percent of those under 73. Among the older patients, age was again the most predictive factor; among the younger patients, the availability of angioplasty was a more important predictor (67 percent of patients in hospitals without angioplasty facilities underwent angiography, as compared with 83 percent in hospitals with such facilities). The next most important variable was recurrent ischemia, which was more predictive at hospitals without angioplasty facilities than at those with them. Both statistical models identified coronary anatomy as the most important predictor of the use and type of revascularization.

CONCLUSIONS

More patients treated with thrombolysis underwent angiography and revascularization before discharge than might be expected. Younger age and the availability of the procedures appeared to be the major determinants of the use of coronary angiography, whereas coronary anatomy largely determined the use and type of revascularization. This process appeared to select low-risk patients for intervention rather than those at higher risk, who would be the most likely to benefit.

Age and outcome with contemporary thrombolytic therapy. Results from the GUSTO-I trial. Global Utilization of Streptokinase and TPA for Occluded coronary arteries trial

BACKGROUND

Elderly patients with acute myocardial infarction have much to gain from reperfusion with thrombolytic therapy but are also at increased risk of adverse events. We examined outcomes according to age of patients receiving thrombolysis in an international trial.

METHODS AND RESULTS

Patients were randomized to streptokinase plus subcutaneous heparin, streptokinase plus intravenous heparin, accelerated tissue plasminogen activator (TPA) plus intravenous heparin, or streptokinase and TPA plus intravenous heparin. Clinical outcomes at 30 days (death, stroke, and nonfatal, disabling stroke) and 1-year mortality were summarized descriptively for patients aged < 65 (n = 24,708), 65 to 74 (n = 11,201), 75 to 85 (n = 4625), and > 85 years (n = 412) and assessed as continuous functions of age. Older patients had a higher-risk profile with regard to baseline clinical and angiographic characteristics. Mortality at 30 days increased markedly with age (3.0%, 9.5%, 19.6%, and 30.3% in the four groups, respectively), as did stroke, cardiogenic shock, bleeding, and reinfarction. Combined death or disabling stroke occurred less often with accelerated TPA in all but the oldest patients, who showed a weak trend toward a lower incidence with streptokinase plus subcutaneous heparin: odds ratio 1.13; 95% confidence interval 0.6, 2.1. Similarly, accelerated TPA treatment resulted in lower 1-year mortality in all but the oldest patients (47% TPA versus 40.3% streptokinase).

CONCLUSIONS

Lower mortality and greater net clinical benefit were seen with accelerated TPA in patients aged < or = 85 years. Because data are limited for patients aged > 85 years, the relative superiority of a given thrombolytic regimen cannot be determined. The interactions of stroke and mortality with newer thrombolytic strategies must be examined explicitly in older patients.

Randomized comparison of coronary thrombolysis achieved with double-bolus reteplase (recombinant plasminogen activator) and front-loaded, accelerated alteplase (recombinant tissue plasminogen activator) in patients with acute myocardial infarction. The RAPID II Investigators

BACKGROUND

The therapeutic benefit of thrombolytic therapy has been shown to correlate directly with completeness (TIMI grade 3 flow) and speed of reperfusion of the infarct-related coronary artery. The purpose of the RAPID II study was to determine whether a double-bolus regimen of reteplase, a recently developed deletion mutant of wild-type tissue plasminogen activator, could improve 90-minute coronary artery patency rates achieved with the most successful standard regimen, an "accelerated" front-loaded infusion of alteplase.

METHODS AND RESULTS

Three hundred twenty-four patients with acute myocardial infarction were randomized to receive (along with intravenous heparin and aspirin) either a 10 plus 10 megaunits double bolus of reteplase or front-loaded alteplase. The primary end point of "patency at 90 minutes, graded according to the TIMI classification" was centrally assessed in a blinded fashion. Infarctrelated coronary artery patency (TIMI grade 2 or 3) and complete patency (TIMI grade 3) at 90 minutes after the start of thrombolytic therapy were significantly higher in the reteplase-treated patients (TIMI grade 2 or 3: 83.4% versus 73.3% for front-loaded alteplase-treated patients, P = .03; TIMI grade 3: 59.9% versus 45.2%, P = .01). At 60 minutes, the incidence of both, patency and complete patency, was also significantly higher in reteplase-treated patients (reteplase versus alteplase, TIMI grade 2 or 3: 81.8% versus 66.1%, P = .01; TIMI grade 3: 51.2% versus 37.4%, P < .03). Reteplase-treated patients required fewer acute additional coronary interventions (13.6% versus 26.5%, P < .01), and 35-day mortality was 4.1% for reteplase and 8.4% for alteplase (P = NS). There were no significant differences between reteplase and alteplase in bleedings requiring a transfusion (12.4% versus 9.7%) or hemorrhagic stroke (1.2% versus 1.9%).

CONCLUSIONS

Reteplase, when given as a double bolus of 10 plus 10 megaunits to patients with acute myocardial infarction, achieves significantly higher rates of early reperfusion of the infarct-related coronary artery and requires significantly fewer acute coronary interventions than front-loaded alteplase without an apparent increased risk of complications.

Influence of early prehospital thrombolysis on mortality and event-free survival (the Myocardial Infarction Triage and Intervention [MITI] Randomized Trial). MITI Project Investigators

The Myocardial Infarction Triage and Intervention Trial of prehospital versus hospital administration of thrombolytic therapy markedly reduced hospital treatment times, but the 2 groups had similar outcomes. However, patients treated < 70 minutes from symptom onset had better short-term outcomes. The purpose of this study was to determine the long-term influence of very early thrombolytic treatment for acute myocardial infarction. A total of 360 patients were followed for vital status and cardiac-related hospital admissions over a period of 34 +/- 16 months. Patients enrolled in the trial had symptoms for < or = 6 hours, ST-segment elevation on the prehospital electrocardiogram, and no risk factors for serious bleeding. They received aspirin and recombinant tissue plasminogen activator either before or after hospital arrival. Primary end points in this study included long-term survival and survival free of death or readmission to the hospital for angina, myocardial infarction, congestive heart failure, or revascularization. Two-year survival was 89% for prehospital- and 91% for hospital-treated patients (p = 0.46). Event-free survival at 2 years was 56% and 64% for prehospital- and hospital-treated patients, respectively (p = 0.42). In patients treated < 70 minutes from symptom onset, 2-year survival was 98%, and it was 88% for those treated later (p = 0.12). Two-year event-free survival was 65% for patients treated early and 59% for patients treated later (p = 0.80). In this trial, poorer long-term survival was associated with advanced age, history of congestive heart failure, and coronary artery bypass surgery performed before the index hospitalization, but not with time to treatment.

Results of the RAPID 1 and RAPID 2 thrombolytic trials in acute myocardial infarction

Two angiographic trials, RAPID 1 in 606 patients and RAPID 2 in 324 patients, assessed angiographic patency after acute myocardial infarction following treatment with reteplase and alteplase. RAPID 1 evaluated three bolus regimens of reteplase in comparison with a 3 h infusion of alteplase. RAPID 2 compared the 10 MU + 10 MU double bolus regimen of reteplase with the accelerated regimen (90 min infusion) of alteplase. The results of these studies showed that reteplase opened more arteries more quickly than did alteplase. Angiography at both 60 and 90 min showed a higher rate of patency and greater TIMI (Thrombolysis in Myocardial Infarction perfusion grade) 3 flow rates with reteplase than with alteplase. In RAPID 1, at 90 min, TIMI 3 flow rates were 63% for reteplase compared to 49% for alteplase (P < 0.05), and in RAPID 2, TIMI 3 flow was 60% vs 45%, respectively, (P < 0.05). Reteplase was convenient and simple to administer, and there were no unexpected complications. Fewer interventional procedures were performed after therapy with reteplase than with alteplase, primarily because coronary angioplasty was required less frequently following acute angiography in patients receiving reteplase. The angiographic profile for reteplase demonstrated in these two trials suggests that this new thrombolytic drug has potential advantages over alteplase: notably, its use can result in earlier and more complete coronary patency. The clinical significance of this finding must be determined in larger clinical trials.

Length of hospital stay after acute myocardial infarction in the Myocardial Infarction Triage and Intervention (MITI) Project registry

OBJECTIVES

This study sought to identify current trends in length of stay in patients with an acute myocardial infarction and to evaluate which demographic, clinical, procedural and hospital-related factors explain the variation and reduction in length of stay observed during the study period.

BACKGROUND

Hospital length of stay is an important contribution to cost of care. Previous studies of length of stay after acute myocardial infarction have been performed largely on administrative data bases and do not reflect current practice patterns.

METHODS

We used univariate and multivariate models to evaluate which demographic, clinical and administrative factors influenced length of stay in 11,932 patients with acute myocardial infarction admitted to 19 Seattle-area hospitals between 1988 and 1994.

RESULTS

Length of hospital stay decreased from (mean +/- SD) 8.5 +/- 8.2 to 6.0 +/- 5.8 days during the study period. Demographic and clinical characteristics known at the time of admission explained only 6% of variation in length of stay, whereas hospital complications, procedure use and type of admitting hospital explained an additional 27% of variation. The use of primary angioplasty and early diagnostic coronary angiography predicted a shorter length of stay; however, none of the measured variables explained the 29% reduction in length of stay that occurred between 1988 and 1994.

CONCLUSIONS

Although hospital complications, procedure use and hospital characteristics are important predictors of length of hospital stay, none of these factors explains the 29% reduction in length of stay observed in postmyocardial infarction patients between 1988 and 1994. It is likely that unmeasured economic and administrative factors play important roles in influencing hospital length of stay.

Planning, implementation, and process monitoring for prehospital 12-lead ECG diagnostic programs

Prehospital 12-lead electrocardiographic (ECG) diagnostic strategies have been proven feasible and effective, provided they are designed and implemented properly. The authors of this communication have expended considerable time and effort in determining appropriate planning, implementation, and process monitoring necessary for successful implementation of a variety of prehospital diagnostic strategies. Many of these issues may not be obvious to an emergency medical services (EMS) director initiating a 12-lead ECG program. This level of attention to protocol development, education, training, inservice education, coordination of the health-care community, objective program assessment, monitoring and continuous quality improvement can serve as a model for other diagnostic EMS programs that may develop as an expanded role for EMS.

Comparison of presentation, treatment, and outcome of acute myocardial infarction in men versus women (the Myocardial Infarction Triage and Intervention Registry)

This study compared the presentation (symptoms and signs), treatment, and outcome of 1,097 consecutive patients (851 men and 246 women) from the Myocardial Infarction Triage and Intervention (MITI) Project Registry with confirmed acute myocardial infarction (AMI), all of whom were initially evaluated in the prehospital setting, met clinical criteria for possible thrombolysis, and were followed throughout their hospital course. Women were older than men and had a higher prevalence of known cardiovascular risk factors, including systemic hypertension and congestive heart failure. The presentation of AMI with respect to symptoms, delay, and hemodynamic and electrocardiographic findings was for the most part indistinguishable between mean and women. Women appeared "undertreated" early in the course of AMI and were half as likely as men to undergo acute catheterization, angioplasty, thrombolysis, or coronary bypass surgery (odds ratio 0.5 [0.3 to 0.7]). The risk for hospital mortality in women was almost twice that for men (odds ratio 1.95 [1.01 to 3.8]). Hospital mortality after AMI was also independently predicted by older age, early evidence of hemodynamic instability, and an intraventricular conduction abnormality on the initial electrocardiogram. Although similar in its presentation, AMI in women is not as aggressively treated, and results in a less favorable outcome than in men. Gender as well as nongender-specific risk factors are important in assessing risk and the likelihood of early intervention after AMI.