N-terminal pro-brain natriuretic peptide and the timing, extent and mortality in ST elevation myocardial infarction

AIMS

While natriuretic peptides have demonstrated diagnostic and prognostic potential in cardiac disorders, little is known about their relationship with the onset and quantification of myocardial infarction. The relationship of serial N-terminal pro-brain natriuretic peptide (NT-proBNP) with duration from symptom onset, infarct size and prognosis in ST elevation myocardial infarction (STEMI) patients treated with primary percutaneous intervention was examined.

METHODS AND RESULTS

Three hundred thirty-one STEMI patients in the COMplement inhibition in Myocardial infarction treated with Angioplasty (COMMA) trial, which evaluated pexelizumab versus placebo, were studied. NT-proBNP (pg/mL) was measured at randomization, 24 h and 72 h; creatine kinase-MB area under the curve was measured at 72 h; and QRS score was assessed at discharge. Prognosis was ascertained from the 90-day composite clinical outcome of death, shock, stroke and congestive heart failure. Multivariate logistical regression was used to adjust for baseline characteristics for models at randomization, 24 h and 72 h. NT-proBNP was higher in patients with longer time from symptom onset (P<0.001) and correlated with measures of infarct size, including the area under the curve (P<0.001) and QRS score (P<0.001). Patients reaching the primary end point had markedly higher NT-proBNP at each sampling period (P<0.001). NT-proBNP at all time points was the strongest independent predictor of the primary end point in the multivariate model: in the 24 h model, only age and 24 h NT-proBNP (C-index 0.83); and only age, Killip class and NT-proBNP was in the 72 h model (C-index 0.85).

CONCLUSIONS

Higher NT-proBNP at 24 h correlated with larger infarct size and worse clinical outcomes. NT-proBNP at baseline, 24 h and 72 h after presentation with acute STEMI, is an independent predictor of a poor outcome and adds clinically useful prognostic information.

Primary coronary angioplasty compared with intravenous thrombolytic therapy for acute myocardial infarction: six-month follow up and analysis of individual patient data from randomized trials

BACKGROUND

Overviews of trials suggest that percutaneous transluminal coronary angioplasty (PTCA) may be more effective than thrombolysis. However, whether these effects are sustained beyond hospital discharge, and the extent to which the results are applicable to a broad cross section of patients and the wider community are unknown. We compared the effectiveness of primary PTCA and thrombolysis in acute myocardial infarction during a 6-month follow-up period.

METHODS

Detailed individual patient data were collected from randomized trials commenced from 1989 to 1996 that compared primary PTCA with thrombolysis. Data were combined to produce estimates of relative reduction in events at 30 days and 6 months for the group and for predefined clinical subgroups. Treatment effects were also assessed in relation to several study-related factors.

RESULTS

Eleven trials were identified. The mortality rate at 30 days was 4.3% for 1348 patients randomized to undergo PTCA, and 6.9% for 1377 patients assigned to thrombolytic therapy (relative risk [RR] 0.62, 95% CI 0.44-0.86, P =.004). At 6 months, the mortality rate was 6.2% for PTCA and 8.2% for thrombolysis (RR 0.73, 95% CI 0.55-0.98, P =.04). Combined death and reinfarction rates at 30 days were 7.0% for PTCA and 12.9% for thrombolysis, with a sustained effect at 6 months (RR 0.60, 95% CI 0.48-0.75, P <.0001). The risk of hemorrhagic stroke at 30 days was lower in the PTCA group (RR 0.06, 95% CI 0.0-0.50, P =.009). The relative treatment effect did not vary across clinically important subgroups, but the absolute benefit varied according to baseline risk. The relative treatment effect varied across the trials and according to the thrombolytic comparator used, the delay in performing PTCA, and the recruitment rate.

CONCLUSION

In the context of these trials, primary PTCA was more effective than thrombolytic therapy in reducing death, reinfarction, and stroke, with the greatest absolute benefit in patients who were at the highest risk. These benefits appear to be sustained for 6 months. The effect of treatment varied significantly across the trials, and this raises issues about how widely the results can be applied.

Clinical characteristics and outcome of patients with early (<2 h), intermediate (2-4 h) and late (>4 h) presentation treated by primary coronary angioplasty or thrombolytic therapy for acute myocardial infarction

AIMS

We examined the clinical characteristics and outcome of patients with early (<2 h), intermediate (2-4 h) and late (>4 h) presentation treated by primary angioplasty or thrombolytic therapy for acute myocardial infarction.

METHODS AND RESULTS

We studied 2635 patients enrolled in 10 randomized trials of primary angioplasty (n=1302) vs thrombolytic therapy (n=1333) in acute myocardial infarction, and baseline characteristics of the two groups were comparable. Increase in presentation delay is associated with older age, female gender, diabetes and an increased heart rate. We classified the patients according to the time delay from symptom onset to presentation into three categories: early presentation (<2 h), intermediate presentation (2-4 h), and late presentation (>or=4 h). At 30 days the combined rate of death, non-fatal reinfarction and stroke in patients presenting early was 5.8% in the angioplasty group vs 12.5% in the thrombolysis group, in patients with intermediate presentation, 8.6% vs 14.2%, respectively, and in patients presenting late 7.7% vs 19.4%, respectively. With increasing time from symptom onset to presentation, all major adverse cardiac event rates show a trend to a larger increase in the thrombolysis group compared to the angioplasty group, both at 30 days and at 6 months after the acute event.

CONCLUSIONS

Major adverse cardiac event rates are lower after angioplasty compared to thrombolysis, irrespective of time to presentation. With increasing time to presentation major adverse cardiac event rates increase after thrombolysis but appear to remain relatively stable after angioplasty.

Provisional versus routine coronary stenting. A review

Coronary stenting is the most commonly used coronary revascularization procedure due to the ease of use, safety and evidence that it has predictably better results in several coronary lesion subsets than balloon angioplasty alone. As opposed to routinely stenting all the stentable coronary lesions, in the provisional stenting approach, all the lesions would first be optimally angioplastied and a stent used only in the patients who would not have as good an outcome with balloon angioplasty alone. There are several theoretical advantages to this approach. The two different approaches are compared in this review. Retrospective studies and studies using immediate vessel recoil after optimal balloon angioplasty seemed to suggest that stent-like results after balloon angioplasty had similar target revascularization rates as stenting. However, a prospective randomized study primarily using angiography to guide provisional stenting suggests better outcome in the routine stenting strategy. If provisional stenting were to have similar long-term results as routine stenting, it has to be guided by techniques other than coronary angiography like coronary flow reserve or intravascular ultrasound. Even then, over half of the balloon angioplasty group will need stenting. Besides, based on prospective randomized studies, this strategy is not economically more attractive than the routine stenting strategy. Therefore routine stenting strategy is justifiable for most operators who use coronary angiography to guide their interventions. With further advancement in the stent technology like drug coating routine stenting may be even further attractive.

Underutilization of reperfusion therapy in eligible African Americans with acute myocardial infarction: Role of presentation and evaluation characteristics

BACKGROUND

Immediate reperfusion therapy to restore coronary blood flow is recommended for all eligible patients with acute myocardial infarction. However, reperfusion therapy is reportedly underutilized among African Americans, even when they are eligible. Reasons for the lack of use have not been fully explored.

METHODS

We examined the demographic, clinical, and treatment data of 10,469 African Americans with acute myocardial infarction who were eligible for reperfusion therapy, enrolled in the National Registry of Myocardial Infarction-2 from June 1994 through March 1998.

RESULTS

The mean age was 62.58 (+/-14.4) years, and 44.7% were female. Although eligible, 47% of the African Americans in this study did not receive reperfusion therapy. In a multivariate analysis, the absence of chest pain at presentation (odds ratio [OR] 0.31, 95% CI 0.26-0.37) and initial admission diagnoses other than definite myocardial infarction (OR for receipt of reperfusion <0.12) were the strongest predictors of lack of early reperfusion therapy. Progressive delays in hospital arrival and hospital evaluation predicted a lower likelihood of early reperfusion. Prior stroke (OR 0.63, 95% CI 0.50-0.78), myocardial infarction (OR 0.75, 95% CI 0.65-0.86), and congestive heart failure (OR 0.49, 95% CI 0.40-0.60) were all associated with lack of reperfusion therapy.

CONCLUSION

Almost half of eligible African American patients with myocardial infarction did not receive reperfusion therapy. Potential reasons may include atypical presentation, patient and institutional delay, and underappreciation of myocardial infarction by care providers. Strategies to address these factors may improve the rate of use of reperfusion therapy.

Ninety-minute exclusion of acute myocardial infarction by use of quantitative point-of-care testing of myoglobin and troponin I

BACKGROUND

Diagnostic strategies with ECG and serum cardiac markers have been used to rule out acute myocardial infarction in 6 to 12 hours. The present study evaluated whether a multimarker strategy that used point-of-care measurement of myoglobin, creatine kinase (CK)-MB, and troponin I could exclude acute myocardial infarction in </=3 hours.

METHODS AND RESULTS

We prospectively enrolled consecutive patients (n=817) in the emergency department who were evaluated for possible acute myocardial infarction. In patients with nondiagnostic ECGs, we measured CK-MB, troponin I, and myoglobin with a point-of-care device at presentation and at 90 minutes, 3 hours, and 9 hours. Standard central laboratory testing of CK-MB was done at the same time intervals, and triage decisions were made by emergency physicians who were unaware of point-of-care results. Sensitivity and negative predictive value were compared for both the multimarker, point-of-care approach and the central laboratory strategy. Sensitivity and negative predictive value for point-of-care combination of myoglobin and troponin I by 90 minutes was 96.9% and 99.6%, respectively. CK-MB measurements and blood sampling at 3 hours did not improve sensitivity or negative predictive value. Median time from sampling to reporting of results was 71.0 minutes for the central laboratory versus 24.0 minutes for the point-of-care device (P<0.001).

CONCLUSIONS

Acute myocardial infarction can be excluded rapidly in the emergency department by use of point-of-care measurements of myoglobin and troponin I during the first 90 minutes after presentation.

Randomized comparison of a novel anticoagulant, vasoflux, and heparin as adjunctive therapy to streptokinase for acute myocardial infarction: results of the VITAL study (Vasoflux International Trial for Acute Myocardial Infarction Lysis)

BACKGROUND

Vasoflux is a low-molecular-weight heparin derivative that inhibits factor IXa activation of factor X and catalyzes fibrin-bound thrombin inactivation by heparin cofactor II. We studied whether vasoflux improves the results of thrombolysis with streptokinase for acute myocardial infarction.

METHODS AND RESULTS

We randomized 277 patients with acute myocardial infarction to standard intravenous unfractionated heparin (UFH) or intravenous vasoflux 1, 4, 8, or 16 mg/kg as a bolus followed by 1, 4, 8, or 16 mg/kg per hour infusion, on top of streptokinase and aspirin, until angiography at 90 minutes. Patency and corrected Thrombolysis in Myocardial Infarction (TIMI) frame count were studied at 60 and 90 minutes. Rates of TIMI grade 3 flow with vasoflux at any dose (35% to 42%) were not different from UFH (41%) at either time point, nor was the corrected TIMI frame count. However, there was an excess of bleeding in the patients randomized to vasoflux 8 or 16 mg/kg: 78% and 71%, compared with 53% for UFH (P =.004 and.043, respectively). Major bleeding was observed in 13% and 28% at these vasoflux doses compared with 8% with UFH (P =.558 and.01, respectively).

CONCLUSION

At doses that increase the risk of bleeding, the addition of vasoflux to streptokinase and aspirin did not lead to improved patency rates compared with UFH. Targeting factor IXa and heparin cofactor II may not be a useful adjunct to thrombolysis.

Underuse of invasive procedures among Medicaid patients with acute myocardial infarction

OBJECTIVES

The purpose of this study was to determine whether underuse of cardiac procedures among Medicaid patients with acute myocardial infarction is explained by or is independent of fundamental differences in age, race, or sex distribution; income, coexistent illness; or location of care.

METHODS

Administrative data from 226 hospitals in New York were examined for 11,579 individuals hospitalized with a primary diagnosis of acute myocardial infarction. Use of various cardiac procedures was compared among Medicaid patients and patients with other forms of insurance.

RESULTS

Medicaid patients were older, were more frequently African American and female, and had lower median household incomes. They also had a higher prevalence of hypertension, diabetes, lung disease, renal disease, and peripheral vascular disease. After adjustment for these and other factors, Medicaid patients were less likely to undergo cardiac catheterization, percutaneous transluminal coronary angioplasty, and any revascularization procedure.

CONCLUSIONS

Factors other than age, race, sex, income, coexistent illness, and location of care account for lower use of invasive procedures among Medicaid patients. The influence of Medicaid insurance on medical practice and process of care deserves investigation.

Optimal Response to Cardiac Arrest study: defibrillation waveform effects

INTRODUCTION

Advances in early defibrillation access, key to the "Chain of Survival", will depend on innovations in defibrillation waveforms, because of their impact on device size and weight. This study compared standard monophasic waveform automatic external defibrillators (AEDs) to an innovative biphasic waveform AED.

MATERIAL AND METHODS

Impedance-compensated biphasic truncated exponential (ICBTE) and either monophasic truncated exponential (MTE) or monophasic damped sine (MDS) AEDs were prospectively, randomly assigned by date in four emergency medical services. The study design compared ICBTE with MTE and MDS combined. This subset analysis distinguishes between the two classes of monophasic waveform, MTE and MDS, and compares their performance to each other and to the biphasic waveform, contingent on significant overall effects (ICBTE vs. MTE vs. MDS). Primary endpoint: Defibrillation efficacy with < or =3 shocks. Secondary endpoints: shock efficacy with < or =1 shock, < or =2 shocks, and survival to hospital admission and discharge. Observations included return of spontaneous circulation (ROSC), refibrillation, and time to first shock and to first successful shock.

RESULTS

Of 338 out-of-hospital cardiac arrests, 115 had a cardiac aetiology, presented with ventricular fibrillation, and were shocked by an AED. Defibrillation efficacy for the first "stack" of up to 3 shocks, for up to 2 shocks and for the first shock alone was superior for the ICBTE waveform than for either the MTE or the MDS waveform, while there was no difference between the efficacy of MTE and MDS. Time from the beginning of analysis by the AED to the first shock and to the first successful shock was also superior for the ICBTE devices compared to either the MTE or the MDS devices, while again there was no difference between the MTE and MDS devices. More ICBTE patients achieved ROSC pre-hospital than did MTE patients. While the rates of ROSC were identical for MTE and MDS patients, the difference between ICBTE and MDS was not significant. Rates of refibrillation and survival to hospital admission and discharge did not differ among the three populations.

CONCLUSIONS

ICBTE was superior to MTE and MDS in defibrillation efficacy and speed and to MTE in ROSC. MTE and MDS did not differ in efficacy. There were no differences among the waveforms in refibrillation or survival.

Early patency of the infarct-related artery after myocardial infarction preserves diastolic filling

A patent infarct-related artery (IRA) following myocardial infarction has been associated with lower mortality, increased systolic function, decreased left ventricular remodeling, and electrical stability. The purpose of this study was to determine whether coronary artery patency early after myocardial infarction is associated with greater early diastolic filling than a closed artery. Radionuclide ventriculograms were performed at a central laboratory on 167 patients who received alteplase for an acute myocardial infarction and had infarct artery patency determined by cardiac catheterization. The peak early filling rate (PEFR) was assessed by 4 different methods: (1) PEFR (EDV/s)--normalized to the end-diastolic volume; (2) PEFR (SV/s)--normalized to the stroke volume; (3) PEFR (ml/s/m(2))--an absolute diastolic filling rate; and (4) PEFR (PER)--normalized to the peak ejection rate. Patients with a closed IRA (n = 16, Thrombolysis In Myocardial Infarction [TIMI] 0 or 1 flow) and patients with an open IRA (n = 151, TIMI 2 or 3 flow) had similar ages, ejection fractions, and cardiac volumes. However, among patients with an occluded IRA, the PEFR was decreased by 12% to 18% by the 4 measures of diastolic filling (3 of 4 methods, p <0.05). PEFR (EDV/s) was 1.69 +/- 0.9 in the occluded group versus 2.06 +/- 0.4 EDV/s in the open artery group (p = 0.005). By multivariate analysis, IRA patency was an independent predictor of the PEFR by all 4 methods. Early coronary artery patency after an acute myocardial infarction preserves diastolic filling. Improved diastolic function may in part explain part of the long-term benefits of a patent IRA after thrombolytic therapy when there is no documented improvement in the ejection fraction.

Socioeconomic status is an important determinant of the use of invasive procedures after acute myocardial infarction in New York State

BACKGROUND

Patient and hospital characteristics influence the use of invasive cardiac procedures. Whether socioeconomic status (SES) has an influence that is independent of these other determinants is unclear. The purpose of the present study was to examine the influence of household income as a measure of SES on the use of invasive cardiac procedures among a large group of patients with acute myocardial infarction.

METHODS AND RESULTS

We analyzed administrative discharge data from 231 nonfederal acute care hospitals in New York State that involved 28 698 black or white inpatients with International Classification of Diseases, Ninth Revision, Clinical Modification code 410.XX in the principal diagnosis position between January 1 and December 31, 1995. Household income was derived from postal ZIP codes and census data. The use of cardiac catheterization, PTCA, CABG, and any revascularization procedure was examined across groups stratified by income. Patients who resided in lower-income neighborhoods were more often female or black, had a higher prevalence of coexistent illness, had a higher use of Medicaid insurance, and were less often admitted to urban hospitals or hospitals that provide on-site CABG and PTCA. Crude and adjusted odds ratios for catheterization, PTCA, CABG, and any revascularization procedure were related to income in a graded fashion. After adjustment, patients in the highest quintile of income were 22% more likely to undergo catheterization, 74% more likely to undergo PTCA, 48% more likely to undergo CABG, and 76% more likely to undergo any revascularization procedure than were patients in the lowest quintile. The difference in cardiac catheterization did not fully account for income-based differences in revascularization, because income remained a significant determinant of revascularization after accounting for whether a catheterization was performed. Even among patients treated in hospitals that provide on-site CABG and PTCA, income was a significant determinant of procedures.

CONCLUSIONS

Lower-income patients hospitalized for acute myocardial infarction are more often female or black, have more coexisting illnesses, and are less often admitted to urban hospitals or hospitals that provide CABG and PTCA. Even after adjustment for these and other factors, lower income is a negative predictor of procedure use.

A randomized trial of the effects of early cardiac serum marker availability on reperfusion therapy in patients with acute myocardial infarction: the serial markers, acute myocardial infarction and rapid treatment trial (SMARTT)

OBJECTIVES

The purpose of this study was to assess whether the immediate availability of serum markers would increase the appropriate use of thrombolytic therapy.

BACKGROUND

Serum markers such as myoglobin and creatine kinase, MB fraction (CK-MB) are effective in detecting acute myocardial infarction (AMI) in the emergency setting. Appropriate candidates for thrombolytic therapy are not always identified in the emergency department (ED), as 20% to 30% of eligible patients go untreated, representing 10% to 15% of all patients with AMI. Patients presenting with chest pain consistent with acute coronary syndrome were evaluated in the EDs of 12 hospitals throughout North America.

METHODS

In this randomized, controlled clinical trial, physicians received either the immediate myoglobin/CK-MB results at 0 and 1 h after enrollment (stat) or conventional reporting of myoglobin/CK-MB 3 h or more after hospital admission (control). The primary end point was the comparison of the proportion of patients within the stat group versus control group who received appropriate thrombolytic therapy. Secondary end points included the emergent use of any reperfusion treatment in both groups, initial hospital disposition of patients (coronary care unit, monitor or nonmonitor beds) and the proportion of patients appropriately discharged from the ED.

RESULTS

Of 6,352 patients enrolled, 814 (12.8%) were diagnosed as having AMI. For patients having AMI, there were no statistically significant differences in the proportion of patients treated with thrombolytic therapy between the stat and control groups (15.1% vs. 17.1%, p = 0.45). When only patients with ST segment elevation on their initial electrocardiogram were compared, there were still no significant differences between the groups. Also, there was no difference in the hospital placement of patients in critical care and non- critical care beds. The availability of early markers was associated with more hospital admissions as compared to the control group, as the number of patients discharged from the ED was decreased in the stat versus control groups (28.4% vs. 31.5%, p = 0.023).

CONCLUSIONS

The availability of 0- and 1-h myoglobin and CK-MB results after ED evaluation had no effect on the use of thrombolytic therapy for patients presenting with AMI, and it slightly increased the number of patients admitted to the hospital who had no evidence of acute myocardial necrosis.

Multicenter, randomized, controlled trial of 150-J biphasic shocks compared with 200- to 360-J monophasic shocks in the resuscitation of out-of-hospital cardiac arrest victims. Optimized Response to Cardiac Arrest (ORCA) Investigators

BACKGROUND

In the present study, we compared an automatic external defibrillator (AED) that delivers 150-J biphasic shocks with traditional high-energy (200- to 360-J) monophasic AEDs.

METHODS AND RESULTS

AEDs were prospectively randomized according to defibrillation waveform on a daily basis in 4 emergency medical services systems. Defibrillation efficacy, survival to hospital admission and discharge, return of spontaneous circulation, and neurological status at discharge (cerebral performance category) were compared. Of 338 patients with out-of-hospital cardiac arrest, 115 had a cardiac etiology, presented with ventricular fibrillation, and were shocked with an AED. The time from the emergency call to the first shock was 8.9+/-3.0 (mean+/-SD) minutes.

CONCLUSIONS

The 150-J biphasic waveform defibrillated at higher rates, resulting in more patients who achieved a return of spontaneous circulation. Although survival rates to hospital admission and discharge did not differ, discharged patients who had been resuscitated with biphasic shocks were more likely to have good cerebral performance.

Optimum percutaneous transluminal coronary angioplasty compared with routine stent strategy trial (OPUS-1): a randomised trial

BACKGROUND

Whether routine implantation of coronary stents is the best strategy to treat flow-limiting coronary stenoses is unclear. An alternative approach is to do balloon angioplasty and provisionally use stents only to treat suboptimum results. We did a multicentre trial to compare the outcomes of patients treated with these strategies.

METHODS

We randomly assigned 479 patients undergoing single-vessel coronary angioplasty routine stent implantation or initial balloon angioplasty and provisional stenting. We followed up patients for 6 months to determine the composite rate of death, myocardial infarction, cardiac surgery, and target-vessel revascularisation.

RESULTS

Stents were implanted in 227 (98.7%) of the patients assigned routine stenting. 93 (37%) patients assigned balloon angioplasty had at least one stent placed because of suboptimum angioplasty results. At 6 months the composite endpoint was significantly lower in the routine stent strategy (14 events, 6.1%) than with the strategy of balloon angioplasty with provisional stenting (37 events, 14.9%, p=0.003). The cost of the initial revascularisation procedure was higher than when a routine stent strategy was used (US$389 vs $339, p<0.001) but at 6 months, average per-patient hospital costs did not differ ($10,206 vs $10,490). Bootstrap replication of 6-month cost data showed continued economic benefit of the routine stent strategy.

INTERPRETATION

Routine stent implantation leads to better acute and long-term clinical outcomes at a cost similar to that of initial balloon angioplasty with provisional stenting.

Relationship of symptom-onset-to-balloon time and door-to-balloon time with mortality in patients undergoing angioplasty for acute myocardial infarction

CONTEXT

Rapid time to treatment with thrombolytic therapy is associated with lower mortality in patients with acute myocardial infarction (MI). However, data on time to primary angioplasty and its relationship to mortality are inconclusive.

OBJECTIVE

To test the hypothesis that more rapid time to reperfusion results in lower mortality in the strategy of primary angioplasty.

DESIGN

Prospective observational study of data collected from the Second National Registry of Myocardial Infarction between June 1994 and March 1998.

SETTING

A total of 661 community and tertiary care hospitals in the United States.

SUBJECTS

A cohort of 27,080 consecutive patients with acute MI associated with ST-segment elevation or left bundle-branch block who were treated with primary angioplasty.

MAIN OUTCOME MEASURE

In-hospital mortality, compared by time from acute MI symptom onset to first balloon inflation and by time from hospital arrival to first balloon inflation (door-to-balloon time).

RESULTS

Using a multivariate logistic regression model, the adjusted odds of in-hospital mortality did not increase significantly with increasing delay from MI symptom onset to first balloon inflation. However, for door-to-balloon time (median time 1 hour 56 minutes), the adjusted odds of mortality were significantly increased by 41% to 62% for patients with door-to-balloon times longer than 2 hours (for 121-150 minutes: odds ratio [OR], 1.41; 95% confidence interval [CI], 1.08-1.84; P=.01; for 151-180 minutes: OR, 1.62; 95% CI, 1.23-2.14; P<.001; and for >180 minutes: OR, 1.61; 95% CI, 1.25-2.08; P<.001).

CONCLUSIONS

The relationship in our study between increased mortality and delay in door-to-balloon time longer than 2 hours (present in nearly 50% of this cohort) suggests that physicians and health care systems should work to minimize door-to-balloon times and that door-to-balloon time should be considered when choosing a reperfusion strategy. Door-to-balloon time also appears to be a valid quality-of-care indicator. JAMA. 2000.

Early angiography versus conservative treatment in patients with non-ST elevation acute myocardial infarction: MITI Investigators. Myocardial Infarction Triage and Intervention

OBJECTIVES

To compare short- and long-term outcome after early invasive or conservative strategies in the treatment of non-ST segment elevation acute myocardial infarction (AMI).

BACKGROUND

It is uncertain whether or not there is benefit from emergent invasive diagnosis and treatment of AMI in patients without ST segment elevation on the admission electrocardiogram (ECG).

METHODS

In a cohort of 1,635 consecutive patients with AMI who presented to hospitals without ST segment elevation on their admission ECG, we compared treatments, hospital course and outcome in 308 patients who presented to hospitals whose initial strategy favored early angiography and appropriate intervention when indicated versus 1,327 similar patients who presented to hospitals that favor a more conservative initial approach.

RESULTS

At baseline, patients admitted to hospitals favoring an early invasive strategy were younger, more predominately Caucasian and had less comorbidity. Early coronary angiography occurred in 58.8% versus 8% (p < 0.001), and early angioplasty was performed in 44.8% versus 6.1% (p < 0.001) in the two different cohorts. Patients treated in hospitals favoring the early invasive strategy had a lower 30-day (5.5% vs. 9.5%, p = 0.026) and four-year mortality (20% vs. 37%, p < 0.001). Multivariate analysis showed a trend towards lower hospital mortality (OR = 0.56, 95% CI: 0.29 to 1.09) and a significant lower long-term mortality (hazard ratio = 0.61, 95% CI: 0.47 to 0.80) in patients admitted to hospitals favoring an early invasive strategy.

CONCLUSIONS

These data suggested that an early invasive strategy in patients with AMI and nondiagnostic ECG changes is associated with lower long-term mortality.

Left ventricular thrombus and subsequent thromboembolism in patients with severe systolic dysfunction

STUDY OBJECTIVES

To determine the frequency of left ventricular (LV) thrombi by echocardiography and to define the predictors of LV thrombus and subsequent thromboembolism.

DESIGN

Retrospective case-control design.

SETTING

Single tertiary care center.

PATIENTS

Twenty-eight patients with LV thrombus in a consecutive series of 144 patients with severe LV dysfunction and follow-up period for a mean of 27.6 months.

MEASUREMENTS AND RESULTS

Thirty-five clinical and echocardiographic variables were evaluated. The mean age of patients with (n = 28) vs patients without (n = 116) LV thrombus was 50.3 +/- 11.0 years vs 54.2 +/- 11.1 years (p = 0.09), with 22 patients (78.6%) and 78 patients (67.2%) being male (p = 0.24), respectively. The mean ejection fraction (EF) for those with vs those without LV thrombus was 17.5 +/- 5.5 vs 20.0 +/- 6.9 (p = 0. 08), with 16 patients (57.1%) and 42 patients (36.2%) having an EF < 20% (p = 0.04), respectively. The groups were similar with respect to other baseline characteristics, comorbid illnesses, and drug therapies other than anticoagulants. All 28 patients with LV thrombus (100%) and 54 of those without LV thrombus (46.6%) were treated with warfarin. Ischemic etiology of the cardiomyopathy (odds ratio, 4.78; 95% confidence interval, 1.51 to 15.11; p = 0.008) and increased LV internal diastolic dimension (LVIDD; odds ratio, 1.10; 95% confidence interval, 1.03 to 1.18; p = 0.004) were found to be independent predictors of thrombus formation. Peripheral embolism occurred in 5 patients (17.9%) vs 13 patients (11.2%) of those with and without LV thrombi, respectively (p = 0.35). Ischemic etiology of the cardiomyopathy (odds ratio, 3.79; 95% confidence interval, 1. 13 to 12.64; p = 0.03) and EF (odds ratio, 0.91; 95% confidence interval, 0.82 to 1.00; p = 0.04) were found to be independent predictors of systemic embolization. The patients with an embolic event suffered a significantly higher mortality (7 of 18 patients; 38.9%) during the follow-up period when compared to those without an embolic event (13 of 126 patients; 10.3%; p < 0.0001).

CONCLUSIONS

We conclude that ischemic cardiomyopathy and dilated LV chamber sizes (LVIDD > 60 mm) are independently associated with LV thrombi. A peripheral embolic event is related to poor long-term survival in this patient group.

Characteristics of Myocardial Infarction Episodes in Two Distant Communities: From the REGICOR Registry in Girona, Spain and the MITI Registry in Greater Seattle, USA

Background: The objective of the study is to compare patient characteristics and outcome after myocardial infarction (MI) between two geographically and socially different communities. Methods/Results: The study was designed as an ecological comparison between a 1-year hospital registry of consecutive MIs in Seattle (1,400,000 inhabitants and a predominantly urban and suburban distribution) and nine hospitals in Giroma (500,000 inhabitants in a predominantly rural distribution). Hospitalization rates for MI are higher in Seattle (standardized rates of 2.5/1000 for men and 0.8/1000 for women) than in Girona (1.5/1000 for men and 0.2/1000 for women). In both registries men under age 60 accounted for 45.5% of cases. Women accounted for 25% of all MI episodes in Seattle and for only 16% in Giromi. Treatment with thrombolytic and beta-blocking drugs was twice as common in Seattle hospitals as in Girona. Hospital mortality in tertiary care hospitals was similar in both registries, but mortality in local hospitals (having no coronary care unit) in Giroma was significantly higher than other hospital mortality rates for MI. Conclusions: The higher in-hospital mortality rate may in large part be explained by the absence of a coronary care unit. However, the dispersion of Girona's population and the lack of specific programs to provide emergent specialized care to possible MI patients may also contribute to the higher in-hospital mortality rate in Girona.

Hospital Protocols and Policies that may Delay Early Identification and Thrombolytic Therapy of Acute Myocardial Infarction Patients

Despite the compelling relationship between early treatment and outcome from reperfusion therapy in patients with acute myocardial infarction, significant delays in early treatment are imposed by the patient, prehospital systems, and hospital processes and protocols used in the identification and treatment of patients with myocardial infarction. A survey instrument designed to determine the prevalence of hospital policies and protocols that might delay or expedite treatment with thrombolytic therapy in patients with acute myocardial infarction was completed by 524 hospital participating in the National Registry for Myocardial Infarction (NRMI). Participating hospitals had treated 17,646 patients with tissue plasminogen activator. The door to drug time for the entire population of patients treated at each hospital was available. Door to drug times were compared between those hospitals that had a positive response to a policy and those that had a negative response to that policy. Among respondent hospitals, thrombolysis was excluded by protocol in 34.4% for age above 75 and in 55% for presentation after 6 hours of chest pain onset. Furthermore, 29.4% of hospitals required routine laboratory testing other than electrocardiography (ECG), including chest x-ray, prior to determination of eligibility for thrombolysis. Door to drug times were shorter in those hospitals with prehospital 12-lead ECG availability, assessment of the 12-lead ECG by the emergency department nurse and physician as soon as it was available, and initiation of thrombolysis by the emergency physician (in patients with clear-cut ST elevation myocardial infarction) without bedside cardiology consultation. Door to drug times were longer in those hospitals in which predecision laboratory results were required, written informed consent was mandated, and drug was initiated in the cardiac intensive care unit rather than in the emergency department itself. Door to drug times were not significantly different in those hospitals with a designated chest pain center compared with those operating under a focused patient care protocol. We conclude that the earliest possible hospital treatment of acute myocardial infarction patients may be precluded by multiple components of emergency department policies and process, many of them inappropriate for safe, efficient, and effective identification and management of these patients.

Changes in the Use of Thrombolytic Therapy in Seattle Area Hospitals from 1988 to 1992: Results from the Myocardial Infarction Triage and Intervention Registry

Background: Thrombolytic therapy has been shown to reduce mortality in select patients with acute myocardial infarction (AMI). The determinants of eligibility for therapy are changing as more information about the safety and efficacy of thrombolytic therapy is obtained. In the United States, there is some concern that thrombolytic therapy is underutilized, particularly in women and older patients. The purpose of this investigation is to examine change in the use of thrombolytic therapy in a single community from the years 1988 to 1992. Particular attention was paid to women and older patients. Methods: From January 1988 through December 1992, 9154 patients who developed AMI were admitted to coronary care units in 19 hospitals in the metropolitan Seattle area. The hospital records of each consecutive patient were reviewed, and key information was entered into the Myocardial Infarction Triage and Intervention database. Patients who developed AMI after hospital admission for another medical condition were excluded, as were the small numbers of patients with AMI complicated by cardiac arrest and resuscitation prior to hospital admission. This population-based study contains first admissions for AMI during the 5 year period of the registry. Results: The use of thrombolytic therapy in all patients increased from 18% to 24% (p <.0001) during the 5 year period; women (10-16%) and patients 75 years and older (3-10%) had proportionately greater increases in utilization. Despite widespread awareness of its importance, the median time from symptom onset to hospital arrival did not change during the 5 years, although there was a slight decrease in the time from hospital arrival to treatment with thrombolytic therapy. Conclusions: The change in use of thrombolytic therapy indicates that age and gender are less often used as exclusions for receiving thrombolytic therapy. It is possible that exclusionary criteria are being modified, with the result that this important treatment is being received by more people. The finding that there was no change in the time from acute symptom onset to hospital arrival requires intensive study. In particular, more needs to be known about patient decisionmaking, and innovative community interventions to reduce delay times must be evaluated.

Risk stratification with a point-of-care cardiac troponin T test in acute myocardial infarction. GUSTOIII Investigators. Global Use of Strategies To Open Occluded Coronary Arteries

Troponin T has been used successfully to risk stratify patients with acute coronary syndromes, but the utility of this approach using a rapid bedside assay in patients undergoing thrombolysis for ST-segment elevation acute myocardial infarction has not been assessed in a large population. We assessed whether a point-of-care, qualitative troponin T test at enrollment could independently risk-stratify patients randomized to receive alteplase or reteplase in the GUSTO-III trial. Complete troponin T data were available for 12,666 patients (84%) enrolled at 550 hospitals. The primary end point was mortality at 30 days, and the predictive ability of an elevated baseline troponin T level was analyzed (after adjustment for baseline characteristics) with multiple logistic regression. Patients with an elevated troponin T result at enrollment (8.9%) had significantly higher mortality at 30 days (unadjusted 15.7% vs 6.2% for negative patients; p = 0.001), which persisted even after adjustment for age, heart rate, location of infarction, Killip class, and systolic blood pressure. In a multivariable regression model, a positive troponin T result added independently to the prediction of 30-day mortality (chi-square 46, p = 0.001). A positive result with qualitative troponin T testing on admission is an independent marker of higher 30-day mortality. Troponin T testing could be a valuable addition to the evaluation strategy for patients with acute myocardial infarction.