Reperfusion therapy in patients with acute myocardial infarction and prior coronary artery bypass graft surgery (National Registry of Myocardial Infarction-2)

We reviewed data from the National Registry of Myocardial Infarction-2 to determine the differences in characteristics and outcomes in patients with acute myocardial infarction (AMI) who have undergone previous coronary artery bypass grafting (CABG), and those who have not, and between post-CABG patients who were treated with alteplase (recombinant tissue-type plasminogen activator [rt-PA]) and those who were treated with primary percutaneous transluminal coronary angioplasty (PTCA). Demographic, therapeutic, and outcome data from patients with AMI were collected at > 1,000 hospitals in the United States in collaboration with National Registry of Myocardial Infarction-2. Of the 45,925 patients receiving reperfusion therapy, 2,544 of the 39,574 treated with rt-PA (6.4%) had a history of CABG, and 375 of the 6,351 treated with primary PTCA (5.9%) had a history of CABG. Patients with a history of CABG were older, more likely to be men, and had more comorbidities, but prior CABG was still an independent predictor of mortality after multivariate regression analysis (odds ratio 1.23; 95% confidence interval 1.05 to 1.44). Among the post-CABG patients who received rT-PA or underwent PTCA, there was no significant difference in in-hospital mortality rate or the combined end point of death and nonfatal stroke. Thus, (1) prior CABG is an independent predictor of mortality, and (2) for post-CABG patients with AMI who are not in shock and who are lytic-eligible, reperfusion therapy with rt-PA and PTCA result in similar outcomes with regard to in-hospital mortality and the combined end point of death and nonfatal stroke.

Weight-adjusted dosing of TNK-tissue plasminogen activator and its relation to angiographic outcomes in the thrombolysis in myocardial infarction 10B trial. TIMI 10B Investigators

Fixed doses of thrombolytic agents are generally administered to patients of varying body weights, and the dose-response relation may be confounded by the variability in patient weight. We hypothesized that higher doses of TNK-tissue plasminogen activator (tPA) per unit body weight would be related to improved flow at 90 minutes after thrombolytic administration. A total of 886 patients with acute myocardial infarction were randomized to receive either a single bolus of 30, 40, or 50 mg of TNK-tPA or front-loaded tPA in the Thrombolysis In Myocardial Infarction (TIMI) 10B trial. The dose of TNK-tPA administered was divided by the patient's weight to arrive at the TNK-tPA dose (mg) per unit body weight (kg), and patients were stratified into tertiles based on mg/kg of TNK-tPA: low dose, 0.2 to 0.39 mg/kg; mid-dose, 0.40 to 0.51 mg/kg; high dose, 0.52 to 1.24 mg/kg. Flow in the culprit and nonculprit arteries was analyzed using the TIMI flow grades and the corrected TIMI frame count (CTFC). The median CTFC in culprit arteries differed between the tertiles (3-way p = 0.007), with the CTFC being 7.2 frames faster in high-dose than in low-dose patients (43.1 +/- 30.1, median 31.2, n = 171 vs 54.6 +/- 34.8, median 38.4, n = 166, 2-way p = 0.002). Patients in the mid- and high-dose tertiles achieved patency more frequently (TIMI grade 2 or 3 flow) by 60 minutes (p = 0.02), and the 90-minute percent diameter stenosis was less severe in patients in the high- versus low-dose tertile (p = 0.03). In nonculprit arteries, the CTFC was faster in high- than in low-dose tertiles (29.6 +/- 13.4, median 26.9, n = 130 vs 34.7 +/- 16.3, median 32.8, n = 108, 3-way p = 0.03, 2-way p = 0.008). In patients who underwent percutaneous transluminal coronary angioplasty (PTCA), the CTFC in culprit arteries after PTCA was fastest in the high- and mid-dose tertiles than in those receiving low doses (2-way p = 0.05). Thus, higher doses per unit body weight of TNK-tPA result in not only faster culprit artery flow, but also faster nonculprit, global, and post-PTCA flow, which may reflect earlier opening, reduced stunning, or improved microvascular function. The greater effectiveness of thrombolysis must be weighed against any increase in risk.

Efegatran sulfate as an adjunct to streptokinase versus heparin as an adjunct to tissue plasminogen activator in patients with acute myocardial infarction. ESCALAT Investigators

BACKGROUND

Previous clinical studies have shown that direct antithrombins can accelerate clot lysis after treatment with streptokinase in acute myocardial infarction (MI). Efegatran is a new direct antithrombin, which in experimental animals has been shown to enhance thrombolysis, reduce rate of reocclusion, and limit infarct size. This study was designed to compare the efficacy of efegatran plus streptokinase versus heparin plus accelerated tissue plasminogen activator (TPA) in coronary reperfusion in acute MI.

METHODS AND RESULTS

In this randomized, dose-finding study (n = 245), we initially explored 4 doses of efegatran sulfate in combination with streptokinase (1.5 million U) given intravenously within 12 hours of symptom onset. The optimal dosage group of 0.5 mg/kg per hour was expanded and compared with heparin plus accelerated TPA. The primary end point was complete patency (Thrombolysis In Myocardial Infarction [TIMI] grade 3) at 90 minutes after thrombolytic therapy, assessed in a core angiographic laboratory. Infarct-related vessel patency (TIMI grade 2 or 3) and complete patency (TIMI grade 3) were 73% and 40% in the efegatran/streptokinase group versus 79% and 53% in the heparin/TPA group (P = not significant). In-hospital mortality rate was 5% for the efegatran/streptokinase group versus 0% for the heparin/TPA group (P = not significant). Major bleeding occurred in 23% of patients in the efegatran/streptokinase group versus 11% in the heparin/TPA group (P = not significant). No intracranial hemorrhage occurred.

CONCLUSIONS

The combination of efegatran plus streptokinase is not superior to the current therapy of heparin and accelerated TPA in achieving early patency. In addition, there is no indication that this experimental treatment can achieve better clinical outcome.

Neurosurgical evacuation of intracranial hemorrhage after thrombolytic therapy for acute myocardial infarction: experience from the GUSTO-I trial. Global Utilization of Streptokinase and tissue-plasminogen activator (tPA) for Occluded Coronary Arteries

BACKGROUND

Intracranial hemorrhage is an uncommon but very dangerous complication in patients receiving thrombolytic therapy for acute myocardial infarction. Neurosurgical evacuation is often an available treatment option. However, the association between neurosurgical evacuation and clinical outcomes in these patients has yet to be determined.

METHODS

The GUSTO-I trial randomly assigned 41,021 patients with acute myocardial infarction to 1 of 4 thrombolytic strategies in 1081 hospitals in 15 countries. A total of 268 patients (0.65%) had an intracranial hemorrhage. We assessed differences in clinical characteristics, neuroimaging features, Glasgow coma scale scores, functional status (disabled: moderate or severe deficit; not disabled: no or minor deficit) and 30-day mortality rate between the 46 patients who underwent neurosurgical evacuation and the 222 patients who did not.

RESULTS

Mortality rate at 30 days for all patients with intracranial hemorrhage was 60%; an additional 27% were disabled. Evacuation was associated with significantly higher 30-day survival (65% versus 35%, P <.001) and a trend toward improved functional status (nondisabling stroke: 20% versus 12%, P =.15).

CONCLUSIONS

Although intracranial hemorrhage is uncommon after thrombolysis for acute myocardial infarction, 87% of patients die or have disabling stroke. Although not definitive, these data indicate that neurosurgical evacuation may be associated with improved clinical outcomes. Physicians treating such patients should consider early neurosurgical consultation and intervention in these patients.

Sex, clinical presentation, and outcome in patients with acute coronary syndromes. Global Use of Strategies to Open Occluded Coronary Arteries in Acute Coronary Syndromes IIb Investigators

BACKGROUND

Studies have reported that women with acute myocardial infarction have in-hospital and long-term outcomes that are worse than those of men.

METHODS

To assess sex-based differences in presentation and outcome, we examined data from the Global Use of Strategies to Open Occluded Coronary Arteries in Acute Coronary Syndromes IIb study, which enrolled 12,142 patients (3662 women and 8480 men) with acute coronary syndromes, including infarction with ST-segment elevation, infarction with no ST-segment elevation, and unstable angina.

RESULTS

Overall, the women were older than the men, and had significantly higher rates of diabetes, hypertension, and prior congestive heart failure. They had significantly lower rates of prior myocardial infarction and were less likely ever to have smoked. A smaller percentage of women than men had infarction with ST elevation (27.2 percent vs. 37.0 percent, P<0.001), and of the patients who presented with no ST elevation (those with myocardial infarction or unstable angina), fewer women than men had myocardial infarction (36.6 percent vs. 47.6 percent, P<0.001). Women had more complications than men during hospitalization and a higher mortality rate at 30 days (6.0 percent vs. 4.0 percent, P<0.001) but had similar rates of reinfarction at 30 days after presentation. However, there was a significant interaction between sex and the type of coronary syndrome at presentation (P=0.001). After stratification according to coronary syndrome and adjustment for base-line variables, there was a nonsignificant trend toward an increased risk of death or reinfarction among women as compared with men only in the group with infarction and ST elevation (odds ratio, 1.27; 95 percent confidence interval, 0.98 to 1.63; P=0.07). Among patients with unstable angina, female sex was associated with an independent protective effect (odds ratio for infarction or death, 0.65; 95 percent confidence interval, 0.49 to 0.87; P=0.003).

CONCLUSIONS

Women and men with acute coronary syndromes had different clinical profiles, presentation, and outcomes. These differences could not be entirely accounted for by differences in base-line characteristics and may reflect pathophysiologic and anatomical differences between men and women.

Combined historical and electrocardiographic timing of acute anterior and inferior myocardial infarcts for prediction of reperfusion achievable size limitation

The historical time of acute symptom onset is not always an accurate indication of the timing of onset of an acute myocardial infarction (AMI). Consideration of electrocardiographic (ECG) timing parameters could supplement historical timing alone as a clinical guide for decisions regarding the use of reperfusion therapy. Three hundred ninety-five patients from 4 trials of thrombolytic therapy conducted in the northwestern United States and western Canada are included in the present study. A total of 316 patients received either streptokinase or tissue plasminogen activator, and 79 received no reperfusion therapy. Historical time of symptom onset was acquired by emergency or cardiology department personnel and recorded on patient report forms. An ECG method for estimating the timing of the AMI, the Anderson-Wilkins (AW) acuteness score, was calculated from the initial standard 12-lead recording by investigators blinded to the knowledge of symptom duration or any other study variables. Tomographic thallium-201 imaging 7 weeks after hospital admission was used to measure final AMI size. The ECG timing method achieved a relation with final AMI size similar to that previously reported for historical timing. The AW acuteness score proved most useful for anterior AMI location when there was a > or = 2 hour delay following symptom onset, but was most useful for the inferior AMI location when there was a < 2 hour delay. Despite a longer delay, patients with high AW acuteness scores had 50% lower final anterior AMI size than those with low scores; and despite a shorter delay, those with low ECG acuteness scores had 50% greater final inferior AMI size than those with high scores. The AW acuteness score combined with the historical estimation of symptom duration should provide a more accurate basis for predicting the potential for limitation of final AMI size than either method alone. These results could potentially provide the basis for developing a new method for noninvasive guidance of clinical decisions regarding administration of reperfusion therapy in the initial evaluation of patients with AMI.

Effects of stroke on medical resource use and costs in acute myocardial infarction. GUSTO I Investigators. Global Utilization of Streptokinase and Tissue Plasminogen Activator for Occluded Coronary Arteries Study

BACKGROUND

Stroke occurs concurrently with myocardial infarction (MI) in approximately 30 000 US patients each year. This number is expected to rise with the increasing use of thrombolytic therapy for MI. However, no data exist for the economic effect of stroke in the setting of acute MI (AMI). The purpose of this prospective study was to assess the effect of stroke on medical resource use and costs in AMI patients in the United States.

METHODS AND RESULTS

Medical resource use and cost data were prospectively collected for 2566 randomly selected US GUSTO I patients (from 23 105 patients) and for the 321 US GUSTO I patients who developed non-bypass surgery-related stroke during the baseline hospitalization. Follow-up was for 1 year. All costs are expressed in 1993 US dollars. During the baseline hospitalization, stroke was associated with a reduction in cardiac procedure rates and an increase in length of stay, despite a hospital mortality rate of 37%. Together with stroke-related procedural costs of $2220 per patient, the baseline medical costs increased by 44% ($29 242 versus $20 301, P<0.0001). Follow-up medical costs were substantially higher for stroke survivors ($22 400 versus $5282, P<0.0001), dominated by the cost of institutional care. The main determinant for institutional care was discharge disability status. The cumulative 1-year medical costs for stroke patients were $15 092 higher than for no-stroke patients. Hemorrhagic stroke patients had a much higher hospital mortality rate than non-hemorrhagic stroke patients (53% versus 15%, P<0.001), which was associated with approximately $7200 lower mean baseline hospitalization cost. At discharge, hemorrhagic stroke patients were more likely to be disabled (68% versus 46%, P=0.002).

CONCLUSIONS

In this first large prospective economic study of stroke in AMI patients, we found that strokes were associated with a 60% ($15 092) increase in cumulative 1-year medical costs. Baseline hospitalization costs were 44% higher because of longer mean lengths of stay. Stroke type was a key determinant of baseline cost. Follow-up costs were more than quadrupled for stroke survivors because of the need for institutional care. Disability level was the main determinant of institutional care and thus of follow-up costs.

TNK-tissue plasminogen activator compared with front-loaded alteplase in acute myocardial infarction: results of the TIMI 10B trial. Thrombolysis in Myocardial Infarction (TIMI) 10B Investigators

BACKGROUND

Bolus thrombolytic therapy is a simplified means of administering thrombolysis that facilitates rapid time to treatment. TNK-tissue plasminogen activator (TNK-tPA) is a highly fibrin-specific single-bolus thrombolytic agent.

METHODS AND RESULTS

In TIMI 10B, 886 patients with acute ST-elevation myocardial infarction presenting within 12 hours were randomized to receive either a single bolus of 30 or 50 mg TNK-tPA or front-loaded tPA and underwent immediate coronary angiography. The 50-mg dose was discontinued early because of increased intracranial hemorrhage and was replaced by a 40-mg dose, and heparin doses were decreased. TNK-tPA 40 mg and tPA produced similar rates of TIMI grade 3 flow at 90 minutes (62.8% versus 62.7%, respectively, P=NS); the rate for the 30-mg dose was significantly lower (54.3%, P=0.035) and was 65. 8% for the 50-mg dose (P=NS). A prespecified analysis of weight-based TNK-tPA dosing using median TIMI frame count demonstrated a dose response (P=0.001). Similar dose responses were observed for serious bleeding and intracranial hemorrhage, but significantly lower rates were observed for both TNK-tPA and tPA after the heparin doses were lowered and titration of the heparin was started at 6 hours.

CONCLUSIONS

TNK-tPA, given as a single 40-mg bolus, achieved rates of TIMI grade 3 flow similar to those of the 90-minute bolus and infusion of tPA. Weight-adjusting TNK-tPA appears to be important in achieving optimal reperfusion; reduced heparin dosing appears to improve safety for both agents. Together with the safety results from the parallel Assessment of the Safety of a New Thrombolytic: TNK-tPA (ASSENT I) trial, an appropriate dose of this single-bolus thrombolytic agent has been identified for phase III testing.

Prediction of 30-day mortality among patients with thrombolysis-related intracranial hemorrhage

BACKGROUND

Limited information exists on risk factors for mortality after thrombolysis-related intracranial hemorrhage. We wished to determine the characteristics associated with 30-day mortality after thrombolysis-related intracranial hemorrhage.

METHODS AND RESULTS

We performed an observational analysis within a randomized trial of 4 thrombolytic therapies, conducted in 1081 hospitals in 15 countries. Patients presented with ST-segment elevation within 6 hours of symptom onset. Our population was composed of the 268 patients who had primary intracranial hemorrhage after thrombolysis. With univariable and multivariable analyses, we identified clinical and brain imaging characteristics that would predict 30-day mortality among these patients. CT or MRI were available for 240 patients (90%). The 30-day mortality rate was 59.7%. Glasgow Coma Scale score, age, time from thrombolysis to symptoms of intracranial hemorrhage, hydrocephalus, herniation, mass effect, intraventricular extension, and volume and location of intracranial hemorrhage were significant univariable predictors. Multivariable analysis of 170 patients with complete data, 98 of whom died, identified the following independent, significant predictors: Glasgow Coma Scale score (chi2, 19.3; P<0. 001), time from thrombolysis to intracranial hemorrhage (chi2, 15.8; P<0.001), volume of intracranial hemorrhage (chi2, 11.6; P<0.001), and baseline clinical predictors of mortality in the overall GUSTO-I trial (chi2, 10.3; P=0.001). The final model had a C-index of 0.931.

CONCLUSIONS

This model provides excellent discrimination between patients who are likely to live and those who are likely to die after thrombolytic-related intracranial hemorrhage; this may aid in making decisions about the appropriate level of care for such patients.

Estimating the proportion of post-myocardial infarction patients who may benefit from prophylactic implantable defibrillator placement from analysis of the CAST registry. Cardiac Arrhythmia Suppression Trial

We defined the proportion of post-myocardial infarction patients who would have been eligible for the Multicenter Automatic Defibrillator Implantation Trial (MADIT) from a population of 94,797 patients with myocardial infarction entered into the Cardiac Arrhythmia Suppression Trial Registry. From this large population, only between 0.3% to 1.7% would have met strict eligibility criteria for MADIT.

Utility of the prehospital electrocardiogram in diagnosing acute coronary syndromes: the Myocardial Infarction Triage and Intervention (MITI) Project

OBJECTIVES

We sought to determine whether the prehospital electrocardiogram (ECG) improves the diagnosis of an acute coronary syndrome.

BACKGROUND

The ECG is the most widely used screening test for evaluating patients with chest pain.

METHODS

Prehospital and in-hospital ECGs were obtained in 3,027 consecutive patients with symptoms of suspected acute myocardial infarction, 362 of whom were randomized to prehospital versus hospital thrombolysis and 2,665 of whom did not participate in the randomized trial. Prehospital and hospital records were abstracted for clinical characteristics and diagnostic outcome.

RESULTS

ST segment and T and Q wave abnormalities suggestive of myocardial ischemia or infarction were more common on both the prehospital and hospital ECGs of patients with as compared with those without acute coronary syndromes (p < or = 0.00001). Those with prehospital thrombolysis were more likely to show resolution of ST segment elevation by the time of hospital admission (14% vs. 5% in patients treated in the hospital, p = 0.004). In patients not considered for prehospital thrombolysis, both persistent and transient ST segment and T or Q wave abnormalities discriminated those with from those without acute coronary ischemia or infarction. Compared with ST segment elevation on a single ECG, added consideration of dynamic changes in ST segment elevation between serial ECGs improved the sensitivity for an acute coronary syndrome from 34% to 46% and reduced specificity from 96% to 93% (both p < 0.00004). Overall, compared with abnormalities observed on a single ECG, consideration of serial evolution in ST segment, T or Q wave or left bundle branch block (LBBB) abnormalities between the prehospital and initial hospital ECG improved the diagnostic sensitivity for an acute coronary syndrome from 80% to 87%, with a fall in specificity from 60% to 50% (both p < 0.000006).

CONCLUSIONS

ECG abnormalities are an early manifestation of acute coronary syndromes and can be identified by the prehospital ECG. Compared with a single ECG, the additional effect of evolving ST segment, T or Q waves or LBBB between serially obtained prehospital and hospital ECGs enhanced the diagnosis of acute coronary syndromes, but with a fall in specificity.

Higher T-wave amplitude associated with better prognosis in patients receiving thrombolytic therapy for acute myocardial infarction (a GUSTO-I substudy). Global Utilization of Streptokinase and Tissue plasminogen Activator for Occluded Coronary Arteries

Increased T-wave amplitude is one of the earliest electrocardiographic (ECG) changes following coronary artery occlusion. Therefore, higher T waves in the presenting electrocardiogram should represent earlier time to treatment and thus be associated with lower mortality following thrombolytic therapy. However, T-wave amplitude has never been evaluated as a prognostic marker in this setting. We examined clinical outcomes in 3,317 patients with acute myocardial infarction (AMI) who underwent thrombolysis in the Global Utilization of Streptokinase and t-PA for Occluded Coronary Arteries (GUSTO-I) Study. Patients were classified as either those with high T waves or those with low T waves. Higher T waves were defined as those >98th percentile of the upper limit of normal. T-wave amplitude was also evaluated as a continuous variable according to infarct location (maximum T-wave amplitude) and as the amount of excess T-wave amplitude above normal (excess T-wave amplitude). Patients with higher T waves had lower 30-day mortality than those without (5.2% vs 8.6%, p = 0.001) and were less likely to develop congestive heart failure (15% vs 24%, p <0.001) or cardiogenic shock (6.1% vs 8.6%, p = 0.023). Higher maximum T-wave amplitude and excess T-wave amplitude were predictive of lower 30-day mortality (chi-square = 67, p <0.001 and chi-square = 33, p <0.001, respectively). These differences remain significant after controlling for other prognostic baseline ECG variables. In addition, T-wave amplitude added prognostic significance after controlling for time to treatment. T-wave amplitude, an often-overlooked component of the electrocardiogram, can add significant prognostic information in initial evaluation of patients with AMI.

Randomized, controlled trial of RheothRx (poloxamer 188) in patients with suspected acute myocardial infarction. RheothRx in Myocardial Infarction Study Group

BACKGROUND

Patients with acute myocardial infarction (AMI) who are not eligible for thrombolytic therapy or primary coronary angioplasty are distinguished by advanced age, complicated medical histories, relatively frequent use of prior revascularization procedures, and worse outcomes than their counterparts who are eligible for reperfusion therapy.

METHODS AND RESULTS

The purpose of this randomized, controlled trial was to determine whether RheothRx, a hemorheologic agent, reduced myocardial infarct size and improved left ventricular function in patients who had suspected AMI at the time of hospital admission and were not eligible for reperfusion therapy. Patients were randomly assigned to RheothRx (n = 97) or placebo (n = 99). Patients in the two groups were similar with respect to age, sex, medical history, and clinical presentation. Enzyme evidence of AMI was present in 69% of the treatment group and 70% of the placebo group. Infarct size measured before hospital discharge was similar in the two groups (14.1% +/- 18.5% vs 11.7% +/- 14.1%, p = 0.60), although left ventricular ejection fraction was lower in the treatment group (47 +/- 14 vs 52 +/- 11, p = 0.026). Hospital mortality rate was 11.3% and 7.1% in patients receiving RheothRx and patients receiving placebo, respectively (p = 0.30). There was a higher occurrence of acute renal dysfunction in the RheothRx group (12% vs 2%, p = 0.005). Because of changes in drug dosage necessitated by the occurrence of acute renal dysfunction, the trial was stopped.

CONCLUSIONS

In this study of patients who had suspected AMI and were not eligible for thrombolytic therapy, RheothRx did not decrease infarct size or favorably alter outcome. The need for effective treatment for this large patient population remains largely unmet.

Use of reperfusion therapy for acute myocardial infarction in the United States: data from the National Registry of Myocardial Infarction 2

BACKGROUND

There is clear evidence that reperfusion therapy improves survival in selected patients with an acute myocardial infarction. However, several studies have suggested that many patients with an acute myocardial infarction do not receive this therapy. Whether this underutilization occurs in patients appropriate for such therapy remains unclear.

METHODS AND RESULTS

We examined the use of reperfusion therapy in patients with an acute myocardial infarction hospitalized at 1470 hospitals participating in the National Registry of Myocardial Infarction 2. We identified 84 663 patients who were eligible for reperfusion therapy as defined by diagnostic changes on the initial 12-lead ECG, presentation to the hospital within 6 hours from symptom onset, and no contraindications to thrombolytic therapy. Twenty-four percent of these eligible patients did not receive any form of reperfusion therapy (7.5% of all patients). When multivariate analyses were used, left bundle-branch block (odds ratio [OR]=0.22; 95% CI=0.20 to 0.24), lack of chest pain at presentation (OR=0.22; 95% CI=0.21 to 0.24), age >75 years (OR=0.40, 95% CI=0.36 to 0.43), female sex (OR=0.88, 95% CI=0.83 to 0.92), and various preexisting cardiovascular conditions were independent predictors that the patient would not receive reperfusion therapy.

CONCLUSIONS

Reperfusion therapy may be underutilized in the United States. Increased use of reperfusion therapy could potentially reduce the unnecessarily high mortality rates observed in women, the elderly, and other patient groups with the highest risk of death from an acute myocardial infarction.

Risk factors for in-hospital nonhemorrhagic stroke in patients with acute myocardial infarction treated with thrombolysis: results from GUSTO-I

BACKGROUND

Nonhemorrhagic stroke occurs in 0.1% to 1.3% of patients with acute myocardial infarction who are treated with thrombolysis, with substantial associated mortality and morbidity. Little is known about the risk factors for its occurrence.

METHODS AND RESULTS

We studied the 247 patients with nonhemorrhagic stroke who were randomly assigned to one of four thrombolytic regimens within 6 hours of symptom onset in the GUSTO-I trial. We assessed the univariable and multivariable baseline risk factors for nonhemorrhagic stroke and created a scoring nomogram from the baseline multivariable modeling. We used time-dependent Cox modeling to determine multivariable in-hospital predictors of nonhemorrhagic stroke. Baseline and in-hospital predictors were then combined to determine the overall predictors of nonhemorrhagic stroke. Of the 247 patients, 42 (17%) died and another 98 (40%) were disabled by 30-day follow-up. Older age was the most important baseline clinical predictor of nonhemorrhagic stroke, followed by higher heart rate, history of stroke or transient ischemic attack, diabetes, previous angina, and history of hypertension. These factors remained statistically significant predictors in the combined model, along with worse Killip class, coronary angiography, bypass surgery, and atrial fibrillation/flutter.

CONCLUSIONS

Nonhemorrhagic stroke is a serious event in patients with acute myocardial infarction who are treated with thrombolytic, antithrombin, and antiplatelet therapy. We developed a simple nomogram that can predict the risk of nonhemorrhagic stroke on the basis of baseline clinical characteristics. Prophylactic anticoagulation may be an important treatment strategy for patients with high probability for nonhemorrhagic stroke, but further study is needed.

Thrombolysis-related intracranial hemorrhage: a radiographic analysis of 244 cases from the GUSTO-1 trial with clinical correlation. Global Utilization of Streptokinase and Tissue Plasminogen Activator for Occluded Coronary Arteries

BACKGROUND AND PURPOSE

Intracranial hemorrhage (ICH) is a serious complication of thrombolytic therapy. We systematically reviewed the radiographic features of 244 cases of symptomatic ICH complicating thrombolysis for acute myocardial infarction in the Global Utilization of Streptokinase and Tissue Plasminogen Activator for Occluded Coronary Arteries (GUSTO-1) trial, correlated these observations with clinical data, and speculated on hemorrhage pathogenesis.

METHODS

CT scans from 244 patients suffering symptomatic ICH were systematically reviewed for selected radiographic features, including ICH type, location, hematoma characteristics, mass effect features, hydrocephalus, and preexisting lesions. Hematoma volume was estimated by computer-assisted volumetric analysis. Data from this analysis were correlated with clinical data including hypertension, anticoagulation, age, thrombolytic regimen, and ICH timing.

RESULTS

Most hemorrhages were large (median [25th, 75th percentile] volume, 72 mL [39, 118]), solitary (66%), lobar (77%), confluent (80%), and intraparenchymal (82%) with a blood/fluid level (82%) and little edema (median [25th, 75th percentile] volume, 9 mL [5, 16]). Hydrocephalus (P<.001), any one mass effect feature (P<.001), intraventricular hemorrhage (P=.022), mottled hematoma appearance (P=.050), and hematoma blood/fluid level (P<.001) were associated with higher hemorrhage volume in the radiographic analysis, as were older age (P=.005), treatment with combined streptokinase and tissue plasminogen activator (P=.034), and hemorrhage onset 8 to 13 hours after treatment (P=.008) in the clinical analysis. Subdural hemorrhage was a high-volume subgroup whose risk increased with antecedent trauma (P=.026) or syncope (P=.006). Deep intraparenchymal hemorrhage was associated with hypertension (P=.016), and multifocal ICH occurred significantly earlier after treatment (P=.002).

CONCLUSIONS

Although the majority of postthrombolytic ICH are large, solitary, and supratentorial, the spectrum is diverse. Features of mass effect reflected the large volumes, and hematoma characteristics of mottling and blood/fluid levels were frequent. Thrombolysis-related coagulopathy and age appear to be the most important identifiable factors in the genesis of postthrombolytic ICH, but the hemorrhage subtype seen may reflect an interaction with other factors such as hypertension, ICH timing, antecedent head trauma, and syncope.

Comparison of primary coronary angioplasty and intravenous thrombolytic therapy for acute myocardial infarction: a quantitative review

OBJECTIVE

To provide a quantitative review of the treatment effects of primary coronary angioplasty vs intravenous thrombolysis for acute myocardial infarction.

DATA SOURCES

Ten randomized trials were identified through computerized bibliographic search of MEDLINE from January 1985 through March 1996 and by queries of principal investigators.

STUDY SELECTION

Single-center and multicenter randomized trials comparing primary angioplasty with intravenous thrombolytic therapy among 2606 patients were included. Four trials compared angioplasty with streptokinase, 3 compared angioplasty with a 3- to 4-hour infusion of tissue-type plasminogen activator, and 3 compared angioplasty with "accelerated" administration of tissue-type plasminogen activator over 90 minutes.

DATA EXTRACTION

Each investigator provided definitions and exact data for outcome events. Odds ratios (ORs), 95% confidence intervals (CIs), and P values were calculated using exact tests for categorical data.

DATA SYNTHESIS

Mortality at 30 days or less was 4.4% for the 1290 patients treated with primary angioplasty compared with 6.5% for the 1316 patients treated with thrombolysis (34% reduction; OR, 0.66; 95% CI, 0.46-0.94; P=.02). The effect was similar among thrombolytic regimens, and no subgroup demonstrated a significant reduction in death. The rates of death or nonfatal reinfarction were 7.2% for angioplasty and 11.9% for thrombolytic therapy (OR, 0.58; 95% CI, 0.44-0.76; P<.001). Angioplasty was associated with a significant reduction in total stroke (0.7% vs 2.0%; P=.007) and hemorrhagic stroke (0.1% vs 1.1%; P<.001).

CONCLUSIONS

Based on outcomes at hospital discharge or 30 days, primary angioplasty appears to be superior to thrombolytic therapy for treatment of patients with acute myocardial infarction, with the proviso that success rates for angioplasty are as good as those achieved in these trials. Data evaluating longer-term outcomes, operator experience, and time delay before treatment are needed before primary angioplasty can be universally recommended as the preferred treatment.

Factors influencing the time to thrombolysis in acute myocardial infarction. Time to Thrombolysis Substudy of the National Registry of Myocardial Infarction-1

BACKGROUND

The Time to Thrombolysis Substudy of the National Registry for Myocardial Infarction provided the opportunity to identify factors that delay thrombolytic treatment of patients with ST-segment elevation acute myocardial infarction.

PARTICIPANTS

Forty-two participating registry hospitals volunteered for the Time to Thrombolysis Substudy.

METHODS

A case report form was developed to collect time points for emergency department arrival (door), recording of the electrocardiogram (ECG) (data), entry of the order to give a thrombolytic drug (decision), and initiation of the thrombolytic infusion (drug) as defined by the National Heart Attack Alert Program. The impact of mode of transportation to the hospital, sex, policy-driven cardiology consultation and/or contact of the primary care physician on door-to-drug time, and each component interval were determined in 1755 patients who were treated with recombinant tissue-type plasminogen activator (A1-teplase). The t test was used for comparison of means and the nonparametric sign test was used for medians.

RESULTS

A minority of patients arrived at the hospital by ambulance, although more women (49.6%) arrived by ambulance than men (40.9%). However, women arrived at hospitals significantly later after onset of symptoms than men. It took half as long for patients arriving by ambulance to be seen by the physician than those who transported themselves to the hospital. It took longer for women to have the initial 12-lead ECG recorded than men. The decision to order a thrombolytic agent was delayed by 22 minutes and median door-to-drug time by 21 minutes in those patients who had a cardiac consultation over those in whom the drug was ordered and infusion was initiated by the emergency physician. Although the initial 12-lead ECG showed ST-segment elevation in 86% of patients who received the thrombolytic drugs, with no difference between men and women and no difference in the rate of cardiology consultation between men and women (77%), door-to-decision time and door-to-drug time were substantially longer for women having consultation than men. There was no significant difference in door-to-decision time between men and women when no consultation was performed, but it still took longer for a drug infusion to be initiated in women. Contacting the primary care physician delayed the decision to give a thrombolytic drug by 18 minutes and the administration of the drug by 20 minutes, but there were no differences between men and women. Preparation of the drug in the pharmacy resulted in significant delay compared with mixing it in the emergency department.

CONCLUSIONS

Hospital practices and policies, including contacting the primary care physician prior to the initiation of a lytic drug, cardiology consultation, and preparation of the drug in the pharmacy rather than in the emergency department, significantly delay the goal of early treatment of patients with ST segment elevation acute myocardial infarction. Delays in hospital arrival for women are compounded by delays in the decision to treat them with a thrombolytic drug and initiation of the drug therapy in those women who receive consultation compared with men. Other delays in acquiring the first ECG and initiating the drug infusion in women are not explained.

Clinical trial results with a new plasminogen activator

Thrombolysis has become an accepted form of therapy for acute myocardial infarction. As demonstrated in the Global Utilization of Streptokinase and t-PA for Occluded Arteries trial, early, complete and sustained patency of the infarct-related coronary artery is correlated with reduced mortality. However, current thrombolytic regimens are able to achieve such patency within 90 min in only 81% of cases. To improve the risk/benefit ratio of thrombolytic therapy, newer agents such as reteplase have been developed to establish more rapid, more complete and more stable coronary artery patency, thus reducing mortality. This report summarizes the pharmacological properties of reteplase. It also summarizes the findings from various animal and clinical studies in which reteplase was compared with alteplase and streptokinase and the findings from animal and clinical studies evaluating infusion, single-bolus, double-bolus, doses of reteplase.

Use and accuracy of state death certificates for classification of sudden cardiac deaths in high-risk populations

In a large cohort of patients with known or suspected coronary disease, we evaluated the characteristics of 407 patients who died after hospital discharge and tested whether the state death certificate can be used to classify deaths as sudden cardiac versus nonsudden. Compared with a paramedic classification system based on heart rhythm, the death certificate-based classification resulted in a sensitivity that ranged from 78% to 85% and a specificity that ranged from 25% to 58%. We conclude that the death certificate can be used to identify cases of sudden cardiac death in patients at high risk; however, there is a substantial rate of false-positive sudden death classification.

Patient-specific predictions of outcomes in myocardial infarction for real-time emergency use: a thrombolytic predictive instrument

BACKGROUND

Thrombolytic therapy can be life-saving in patients with acute myocardial infarction. However, if given too late or insufficiently selectively, it may provide little benefit but still cause serious complications and incur substantial costs.

OBJECTIVE

To develop a thrombolytic predictive instrument for real-time use in emergency medical service settings that could 1) identify patients likely to benefit from thrombolysis and 2) facilitate the earliest possible use of this therapy.

DESIGN

Creation and validation of logistic regression-based predictive instruments based on secondary analysis of clinical data.

PATIENTS

4911 patients who had acute myocardial infarction and ST-segment elevation on electrocardiogram; 3483 received thrombolytic therapy.

MEASUREMENTS

Data were obtained from 13 major clinical trials and registries and directly from medical records, including electrocardiograms obtained at presentation. Input variables include presenting clinical and electrocardiography features; predictive models generate probabilities for acute (30-day) mortality if and if not treated with thrombolysis, 1-year mortality rates if and if not treated with thrombolysis, cardiac arrest if and if not treated with thrombolysis, thrombolysis-related intracranial hemorrhage, and thrombolysis-related major bleeding episode requiring transfusion. Together, these models constitute the thrombolytic predictive instrument.

RESULTS

The predictive models generated the following mean predictions for patients in the Thrombolytic Predictive instrument Database: 30-day mortality rate, 7.1%; 1-year mortality rate, 10.9%; rate of cardiac arrest, 3.7%; rate of thrombolysis-related intracranial hemorrhage. 0.6%; and rate of other thrombolysis-related major bleeding episodes, 5.0%. They discriminated with between persons having and those not having the predicted outcome; areas under the receiver-operating characteristic (ROC) curve were between 0.77 and 0.84 for the five outcomes. Calibration between each instrument's predicted and observed served rates was excellent. Validation of the predictive instruments of 30-day and 1-year mortality, done on a separate test dataset, yielded areas under the ROC curve of 0.76 for each

CONCLUSIONS

After the basic features of a clinical presentation are entered into a computerized electrocardiograph, the predictions of the thrombolytic predictive instrument can be printed on the electrocardiogram report. This decision aid may facilitate earlier and more appropriate use of thrombolytic therapy in patients with acute myocardial infarction.

Long-term outcome in acute myocardial infarction patients admitted to hospitals with and without on-site cardiac catheterization facilities. MITI Investigators. Myocardial Infarction Triage and Intervention

BACKGROUND

Previous studies have documented the strong association between availability of on-site cardiac catheterization facilities and increased use of coronary angiography in patients with acute myocardial infarction (AMI). Although these studies have shown little influence of the availability of catheterization labs on hospital mortality, no long-term follow-up has been reported.

METHODS AND RESULTS

From a cohort of 12,331 AMI patients admitted to 19 Seattle area hospitals, we compared long-term outcome in 7985 patients admitted to hospitals with and 4346 patients admitted to hospitals without on-site catheterization labs. During the index hospitalization, patients admitted to hospitals with on-site catheterization were more likely to undergo coronary angiography (67.1% versus 39.3%, P<.0001), coronary angioplasty (32.5% versus 13.2%, P<.0001), or coronary bypass surgery (12.5% versus 9.5%, P<.0001). At 3-year follow-up, patients admitted to hospitals with on-site catheterization labs were more likely to undergo postdischarge angiography (19.2% versus 15.2%, P=.0001) and coronary angioplasty (11.6% versus 8.2%, P<.0001). This was associated with approximately $2500.00 per patient in higher cumulative costs. Despite this higher rate of procedure use, there was no association between admission to a hospital with on-site catheterization facilities and lower long-term mortality (multivariate hazard ratio, 1.0; 95% CI, 0.93 to 1.1., the hazard being associated with admission to hospitals with on-site catheterization facilities).

CONCLUSIONS

In an urban area with unconstrained patient transfer mechanisms and high overall cardiac procedure use rates, AMI patients admitted to hospitals without on-site catheterization facilities were managed with fewer procedures during hospitalization and follow-up. This more conservative treatment approach was not associated with any observed increase in long-term mortality.