Atenolol use and clinical outcomes after thrombolysis for acute myocardial infarction: the GUSTO-I experience. Global Utilization of Streptokinase and TPA (alteplase) for Occluded Coronary Arteries

OBJECTIVES

We assessed the use and effects of acute intravenous and later oral atenolol treatment in a prospectively planned post hoc analysis of the GUSTO-I dataset.

BACKGROUND

Early intravenous beta blockade is generally recommended after myocardial infarction, especially for patients with tachycardia and/or hypertension and those without heart failure.

METHODS

Besides one of four thrombolytic strategies, patients without hypotension, bradycardia or signs of heart failure were to receive atenolol 5 mg intravenously as soon as possible, another 5 mg intravenously 10 min later and 50 to 100 mg orally daily during hospitalization. We compared the 30-day mortality of patients given no atenolol (n=10,073), any atenolol (n=30,771), any intravenous atenolol (n=18,200), only oral atenolol (n=12,545) and both intravenous and oral drug (n=16,406), after controlling for baseline differences and for early deaths (before oral atenolol could be given).

RESULTS

Patients given any atenolol had a lower baseline risk than those not given atenolol. Adjusted 30-day mortality was significantly lower in atenolol-treated patients, but patients treated with intravenous and oral atenolol treatment vs. oral treatment alone were more likely to die (odds ratio, 1.3; 95% confidence interval, 1.0 to 1.5; p=0.02). Subgroups had similar rates of stroke, intracranial hemorrhage and reinfarction, but intravenous atenolol use was associated with more heart failure, shock, recurrent ischemia and pacemaker use than oral atenolol use.

CONCLUSIONS

Although atenolol appears to improve outcomes after thrombolysis for myocardial infarction, early intravenous atenolol seems of limited value. The best approach for most patients may be to begin oral atenolol once stable.

Estrogen treatment induces elevated expression of HMG1 in MCF-7 cells

The high mobility group (HMG) 1 protein is a highly conserved and ubiquitous chromosomal protein found enriched in active chromatin. In this study, we have investigated the effect of estrogen on the expression of the human high mobility group protein HMG1 gene and found that the HMG1 mRNA level in MCF-7 cells was sharply increased 2.5-fold after 30 min of estrogen treatment. Under continuous estrogen treatment, the HMG1 mRNA level decreased to a 1.5 times that of the basal level at 90 min and remained at this elevated level under estrogen treatment for up to 24 h. These results support the recent finding by Verrier et al. (C.S. Verrier, 1997, Mol. Endocrinol. 11, 1009-1019) that HMG1 promotes the binding of the estrogen receptor to the estrogen response element and further reinforce our believe that HMG1 plays a significant role in estrogen-induced gene expression.

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.

Multiple atrioventricular nodal pathways in humans: electrophysiologic demonstration and characterization

INTRODUCTION

Multiple AV nodal pathway physiology can be demonstrated in certain patients with clinical AV reentrant tachycardia.

METHODS AND RESULTS

Evidence suggesting multiple AV nodal pathway conduction was present in seven (two males; age range 15 to 75 years) of 78 patients (9%) who underwent electrophysiologic studies for AV nodal tachycardia. The presence of two discrete discontinuities in the AV nodal conduction curves suggested triple AV nodal pathway conduction. Detailed mapping of their retrograde atrial activation sequence was performed along the tricuspid annulus from the coronary sinus ostium to the His-bundle electrogram recording site. Three zones (anterior, middle, and posterior) correspond to the upper, middle, and lower third of the triangle of Koch, respectively. The fast pathway exits were determined as anterior (4/7) or middle (3/7), the intermediate pathway exits as middle (4/7) or posterior (3/7), and the slow pathway exits as middle (1/7) or posterior (6/7). Other evidence suggesting multiple AV nodal pathway conduction includes: (1) triple ventricular depolarizations from a single atrial impulse; (2) sequential dual ventricular echoes; (3) spontaneous transformation between the slow-fast and fast-slow forms of AV nodal reentrant tachycardia; and (4) persistent cycle length alternans during AV nodal reentrant tachycardia. In four patients, all three pathways were shown to be involved in AV nodal echoes or reentrant tachycardia.

CONCLUSION

Multiple AV nodal pathways are not uncommon and can be identified by careful electrophysiologic elucidation and mapping technique.

Clinical determinants of mortality in patients with angiographically diagnosed ischemic or nonischemic cardiomyopathy

OBJECTIVES

We sought to characterize the clinical determinants of mortality in patients with angiographically diagnosed ischemic or nonischemic cardiomyopathy.

BACKGROUND

Patients with ischemic cardiomyopathy may have a worse prognosis than patients with nonischemic cardiomyopathy. Few studies have assessed the effect of ischemic versus nonischemic etiology on outcomes.

METHODS

We analyzed prospectively collected data on 3,787 patients with a left ventricular ejection fraction < or = 40% who underwent coronary angiography. Patients were considered to have ischemic cardiomyopathy (n = 3,112) if they had a history of myocardial infarction, percutaneous transluminal coronary angioplasty, coronary artery bypass graft surgery or at least one major epicardial coronary artery with > or = 75% stenosis; all others were considered to have nonischemic cardiomyopathy (n = 675).

RESULTS

The median age, ejection fraction and proportion of patients with New York Heart Association functional class III or IV symptoms for the nonischemic and ischemic groups were 55 years versus 63 years, 27% versus 32% and 57% versus 25%, respectively. After adjustment for baseline clinical risk factors and presenting characteristics, ischemic etiology remained an important independent predictor of 5-year mortality (p < 0.0001). The extent of coronary artery disease was a better predictor of survival than ischemic or nonischemic etiology (log likelihood chi-square 700 vs. 675, respectively).

CONCLUSIONS

Ischemic etiology is a significant independent predictor of mortality in patients with cardiomyopathy. However, the extent of coronary artery disease contributes more prognostic information than the clinical diagnosis of ischemic or nonischemic cardiomyopathy. Further research is needed to refine the clinical definition of ischemic cardiomyopathy so that physicians can appropriately prescribe treatment and accurately predict outcome.

Complete amino acid sequence of ananain and a comparison with stem bromelain and other plant cysteine proteases

The amino acid sequences of ananain (EC3.4.22.31) and stem bromelain (3.4.22.32), two cysteine proteases from pineapple stem, are similar yet ananain and stem bromelain possess distinct specificities towards synthetic peptide substrates and different reactivities towards the cysteine protease inhibitors E-64 and chicken egg white cystatin. We present here the complete amino acid sequence of ananain and compare it with the reported sequences of pineapple stem bromelain, papain and chymopapain from papaya and actinidin from kiwifruit. Ananain is comprised of 216 residues with a theoretical mass of 23464 Da. This primary structure includes a sequence insert between residues 170 and 174 not present in stem bromelain or papain and a hydrophobic series of amino acids adjacent to His-157. It is possible that these sequence differences contribute to the different substrate and inhibitor specificities exhibited by ananain and stem bromelain.

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.

Strategies for diagnosing HIV-1 infection in atypical Western blots

The Western blot (WB) has long been used to confirm positive ELISAs for diagnosing HIV-1 infections. However, some WB patterns may result in "indeterminate" or controversial reports thus impeding early diagnoses or accurate diagnoses. The interpretation of HIV-1 WB has no "gold standard" criterion. Incomplete antibody profiles on WB strips can be interpreted as positive or indeterminate according to different criteria. The possibility of HIV-2 infection was further checked in these serum samples. However, no reactivity to synthetic peptide of HIV-2 gp36 had been found. Serial WB analyses are important for attaining early diagnoses of HIV-1 infections as well as for evaluating clinical stages. Temporal changes on WB patterns of serial serum samples provide the evidence of seroconversion in individuals with risk behaviours and indeterminate WB. In late stage of HIV-1 infection, the reactivity to gag, pol and env antigen groups may decrease and result in indeterminate WB. We propose to diagnose HIV-1 infection and to differentiate the infection of HIV-1 from HIV-2 in these cases by using nested polymerase chain reaction (PCR) to demonstrate the presence of HIV-1 specific vpu gene.

Incidence and predictors of bleeding after contemporary thrombolytic therapy for myocardial infarction. The Global Utilization of Streptokinase and Tissue Plasminogen activator for Occluded coronary arteries (GUSTO) I Investigators

BACKGROUND

Although the benefit of thrombolytic therapy in reducing mortality in acute myocardial infarction is well established, the types of bleeding and risk factors for bleeding are less well described in large trials.

METHODS AND RESULTS

We analyzed the baseline characteristics, outcomes, and incidence of bleeding by location, severity, and treatment assignment among 41,021 patients in the GUSTO-I trial of thrombolysis for acute myocardial infarction. Of the 40,903 patients for whom there were complete data, 1.2% suffered severe bleeding and 11.4% experienced moderate hemorrhage at a variety of sites. The most common sources of bleeding were procedure related. The thrombolytic regimen was strongly related to the incidence of bleeding; comparatively more bleeding was seen with the therapies of streptokinase plus intravenous heparin and the streptokinase and tissue plasminogen activator plus intravenous heparin combination. In multivariate analysis, the four most powerful independent predictors of hemorrhage were older age, lighter body weight, female sex, and African ancestry; they remained the most important predictors of bleeding when multivariate analysis was performed on patients who did not undergo invasive procedures. The presence of serious hemorrhage was associated with other undesirable outcomes (recurrent events, left ventricular dysfunction, arrhythmia, or stroke).

CONCLUSIONS

Important predictors of bleeding in this population are increased age, lighter weight, female sex, African ancestry, and experiencing invasive procedures. Other nonhemorrhagic adverse clinical outcomes were associated with moderate and severe bleeding, which was in turn associated with increased length of hospital stay and mortality at 30 days.

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.

Incidence and impact on outcome of streptokinase allergy in the GUSTO-I trial. Global Utilization of Streptokinase and t-PA in Occluded Coronary Arteries

We evaluated allergic reactions in 20,201 patients randomized to the streptokinase arms of The Global Utilization of Streptokinase and t-PA (Tissue Plasminogen Activator) in Occluded Coronary Arteries (GUSTO-I) trial, and tested the hypothesis that patients with streptokinase allergy would exhibit higher mortality. After adjusting for baseline variables and time of death, we found comparable coronary patency, left ventricular function, mortality, and bleeding complications between patients with versus those without streptokinase allergy.

Predictors of outcome of reperfusion therapy

The physician wishing to estimate the risk of death for a patient experiencing acute myocardial infarction can rapidly use parameters available on first seeing the patient to estimate the expected mortality and can update this risk during the early phase of the event. From the initial evaluation, factors that exclude patients from reperfusion therapy constitute a substantially elevated risk. Older age, haemodynamic distress, and markers of ongoing ischaemia provide a large amount of prognostic information from the initial exam. Careful surveillance for additional complications allows continuous risk assessment during the early course.

Effects of dopamine agonists on Cebus apella monkeys with previous long-term exposure to fluphenazine

Sixty-one weeks after 48 weeks of treatment with fluphenazine decanoate or placebo, 37 socially living Cebus apella monkeys were evaluated for differences in dopaminergic sensitivity by exposure to 0.75 mg/kg, i.m. of amphetamine (AMPH) (indirect agonist) and apomorphine (APOM) (direct agonist). The fluphenazine-treated animals differed (p < or = 0.05) from control animals on some hourly measures of composite behavioral variables (CBVs). Animals exposed to fluphenazine showed a greater decrease in the aggressiveness CBV and a smaller decrease in self- and environment-directed behaviors than placebo animals. CBVs for normal locomotion and directs affiliation showed no significant differences. The fluphenazine-treated group showed greater agonist induction of stereotypic behavior (p < or = 0.01), and larger decreases in prolactin response to AMPH (p < or = 0.05). Our findings indicate that following extended treatment with an antipsychotic there is increased sensitivity to dopamine, as evidenced by stereotypies and possibly hypophyseal responsiveness.

Coronary revascularization surgery after myocardial infarction: impact of bypass surgery on survival after thrombolysis. GUSTO Investigators. Global Utilization of Streptokinase and Tissue Plasminogen Activator for Occluded Coronary Arteries

OBJECTIVES

This study sought to investigate the impact of surgical revascularization on outcome after myocardial infarction.

BACKGROUND

Small variations in rates of coronary artery bypass graft surgery (CABG) were noted among thrombolytic regimens in the Global Utilization of Streptokinase and Tissue Plasminogen Activator for Occluded Coronary Arteries (GUSTO) trial, prompting the question of whether survival differences were partly related to differences in CABG rates.

METHODS

Patients in the GUSTO trial were randomized to one of four thrombolytic strategies. Of 40,861 patients with complete data, 3,526 underwent surgical revascularization during their initial hospital admission. Thirty-day and 1-year mortality rates were estimated using Kaplan-Meier techniques, and the impact of CABG as a time-dependent covariate on death was evaluated using a Cox survival model, adjusting for baseline prognostic factors.

RESULTS

The median time from study enrollment to CABG was 7 days across treatment groups. A 15% reduction in mortality for the tissue-type plasminogen activator (t-PA)-treated group was evident by the seventh day. Bypass surgery was a significant independent predictor of 30-day mortality (risk ratio 1.87) and a weaker predictor of 1-year mortality (risk ratio 1.21). Operative mortality was highest in patients with acute mitral regurgitation, ventricular septal defect or poor left ventricular function and in those undergoing CABG within the first 4 days of randomization.

CONCLUSIONS

The survival benefit of accelerated t-PA was not related to surgical revascularization. Bypass surgery was associated with excess mortality in the first year, but the added short-term mortality associated with CABG may be balanced by anticipated long-term benefit in specific groups of patients.

Initial clinical experience with an implantable human atrial defibrillator

Low energy biatrial shock is an effective means of restoring sinus rhythm in patients with atrial fibrillation (AF). Ventricular proarrhythmia is avoided provided that shocks are well synchronized to R waves that are not at closely coupled intervals or preceded by long-short cycles. Based on these principles, an implantable atrial defibrillator has been developed and was implanted in three patients with drug refractory paroxysmal AF. The device detects AF via an actively fixed right atrial and a self-retaining coronary sinus defibrillating leads, and delivers 3/3 ms biphasic shocks up to 300 V synchronized to the R wave. The mean implant threshold (ED50) was 195 V (1.8 J). and minimum voltage at conversion during follow-up assessments at 1, 3, and 6 months were 260 V, 2.5 J. 250 V, 2.3 J, and 300 V, 3.0 J respectively. Detection of AF was 100% specific and shocks were 100% synchronized, although only a proportion of synchronized R waves were considered suitable for shock delivery primarily because of closely coupled cycles. Three patients had 9 spontaneous AF episodes, 8/9 (89%) successfully defibrillated by shocks of 260-300 V. Sedation was not used in 4 out of 9 (45%) episodes. Backup ventricular pacing was initiated by the device in 6 out of (67%) episodes. One patient had more frequent AF after lead placement, which subsided after a change of medication. There was no ventricular proarrhythmia. It is concluded that an implantable atrial defibrillator is a viable therapy for selected patients with paroxysmal AF. The device is capable of accurate AF detection, R wave synchronization and ventricular support pacing after successful defibrillation of AF.

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.

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.

One-year results from the Global Utilization of Streptokinase and TPA for Occluded Coronary Arteries (GUSTO-I) trial. GUSTO-I Investigators

BACKGROUND

In the randomized Global Utilization of t-PA and Streptokinase for Occluded Coronary Arteries (GUSTO-I) trial, 41021 patients received one of four thrombolytic regimens. Patients treated with accelerated tissue plasminogen activator (TPA) had a lower 30-day mortality rate (6.3%) than those treated with the other regimens (7.3%, combined streptokinase groups).

METHODS AND RESULTS

Each patient who was alive at 30 days was sent a return postcard to ascertain vital status at 1 year. If the postcard was not returned, the patient (or an alternate specified at randomization) was contacted by telephone. A locator service was used in the United States for patients who could not be located by these methods. Final follow-up was 96% worldwide. One-year mortality rates remained in favor of accelerated TPA (9.1%) over streptokinase with subcutaneous heparin (10.1%, P = .011) and streptokinase with intravenous heparin (10.1%, P = .009). Combination therapy had an intermediate 1-year mortality (9.9%); this outcome was statistically indistinguishable from that with streptokinase (P = .47) but was marginally different from that with accelerated TPA (P = .05).

CONCLUSIONS

The 1-year results demonstrated a saving of 10 lives per 1000 patients treated with accelerated TPA versus streptokinase and subcutaneous or intravenous heparin. Combination thrombolytic therapy had an intermediate benefit but offered no advantage over accelerated TPA treatment alone.

Economic assessment of platelet glycoprotein IIb/IIIa inhibition for prevention of ischemic complications of high-risk coronary angioplasty. EPIC Investigators

BACKGROUND

In the EPIC trial, c7E3 Fab, an antiplatelet IIb/ IIIa receptor antibody, reduced 30-day ischemic end points after high-risk coronary angioplasty by 35% and 6-month ischemic events by 23% but increased in-hospital bleeding episodes.

METHODS AND RESULTS

Of the 2099 patients randomized in EPIC, data were collected on 2038 (97%) for prospective hospital cost and major resources. Physician fees were estimated from the Medicare Fee Schedule. Regression analysis was used to examine the economic tradeoff between reduced ischemic events and increased major bleeding during the initial hospitalization. A potential cost savings of $622 per patient during the initial hospitalization from reduced acute ischemic events with c7E3 Fab was offset by an equivalent rise ($521) in costs as the result of an increase in bleeding episodes. Baseline medical costs for the bolus and infusion c7E3 Fab arm averaged $13,577 (exclusive of drug cost) compared with $13,434 for placebo (P = .42). During the 6-month follow-up, c7E3 Fab decreased repeat hospitalization rates by 23% (P = .004) and repeat revascularization by 22% (P = .04), producing a mean $1270 savings per patient (exclusive of drug cost) (P = .018). With a cost of $1407 for the bolus and infusion c7E3 Fab regimen, the cumulative net 6-month cost to switch from standard care to routine c7E3 Fab averaged $293 per patient.

CONCLUSIONS

In high-risk coronary angioplasty, aggressive platelet inhibition with c7E3 Fab, by significantly reducing ischemic events and repeat revascularization, recoups most of the cost of therapy and has the potential to pay for itself.

Multivariable prognostic models: issues in developing models, evaluating assumptions and adequacy, and measuring and reducing errors

Multivariable regression models are powerful tools that are used frequently in studies of clinical outcomes. These models can use a mixture of categorical and continuous variables and can handle partially observed (censored) responses. However, uncritical application of modelling techniques can result in models that poorly fit the dataset at hand, or, even more likely, inaccurately predict outcomes on new subjects. One must know how to measure qualities of a model's fit in order to avoid poorly fitted or overfitted models. Measurement of predictive accuracy can be difficult for survival time data in the presence of censoring. We discuss an easily interpretable index of predictive discrimination as well as methods for assessing calibration of predicted survival probabilities. Both types of predictive accuracy should be unbiasedly validated using bootstrapping or cross-validation, before using predictions in a new data series. We discuss some of the hazards of poorly fitted and overfitted regression models and present one modelling strategy that avoids many of the problems discussed. The methods described are applicable to all regression models, but are particularly needed for binary, ordinal, and time-to-event outcomes. Methods are illustrated with a survival analysis in prostate cancer using Cox regression.

Multivariable prognostic models: issues in developing models, evaluating assumptions and adequacy, and measuring and reducing errors

Multivariable regression models are powerful tools that are used frequently in studies of clinical outcomes. These models can use a mixture of categorical and continuous variables and can handle partially observed (censored) responses. However, uncritical application of modelling techniques can result in models that poorly fit the dataset at hand, or, even more likely, inaccurately predict outcomes on new subjects. One must know how to measure qualities of a model's fit in order to avoid poorly fitted or overfitted models. Measurement of predictive accuracy can be difficult for survival time data in the presence of censoring. We discuss an easily interpretable index of predictive discrimination as well as methods for assessing calibration of predicted survival probabilities. Both types of predictive accuracy should be unbiasedly validated using bootstrapping or cross-validation, before using predictions in a new data series. We discuss some of the hazards of poorly fitted and overfitted regression models and present one modelling strategy that avoids many of the problems discussed. The methods described are applicable to all regression models, but are particularly needed for binary, ordinal, and time-to-event outcomes. Methods are illustrated with a survival analysis in prostate cancer using Cox regression.

Hepatitis related to the Chinese medicine Shou-wu-pian manufactured from Polygonum multiflorum

Hepatitis developed in a 31-y-old pregnant Chinese woman after consumption of Shou-Wu-Pian, a proprietary Chinese medicine prepared from Polygonum multiflorum. Tests for viral hepatitis were negative and there was no evidence of other systemic disease. The herbal preparation is commonly available in the Orient and China towns in western countries. Cases of herb-induced hepatitis reported in China are reviewed.

Nonsustained ventricular tachycardia in coronary artery disease: relation to inducible sustained ventricular tachycardia. MUSTT Investigators

BACKGROUND

Many physicians believe that electrocardiographic characteristics of nonsustained ventricular tachycardia correlate with the risk for sudden death in survivors of myocardial infarction. Sustained ventricular tachycardia induced by programmed electrical stimulation has also been shown to predict sudden death.

OBJECTIVE

To determine whether electrocardiographic characteristics of spontaneous nonsustained ventricular tachycardia can predict the inducibility of sustained ventricular tachycardia by programmed electrical stimulation in patients with coronary artery disease having abnormal ventricular function.

DESIGN

Observational cohort study.

SETTING

70 clinical electrophysiology laboratories in the United States and Canada.

PATIENTS

1480 consecutive patients with coronary artery disease, left ventricular ejection fraction of 0.40 or less, and asymptomatic nonsustained ventricular tachycardia.

INTERVENTION

Electrophysiologic study attempting to induce sustained monomorphic ventricular tachycardia.

MEASUREMENTS

Daily frequency, duration, and cycle length of spontaneous episodes of nonsustained ventricular tachycardia, measured by standard electrocardiographic recordings.

RESULTS

No statistically significant difference in the frequency or duration of spontaneous nonsustained ventricular tachycardia was seen between patients with and those without inducible sustained ventricular tachycardia. Rates of spontaneous tachycardia were slightly slower in patients with inducible ventricular tachycardia than in patients without inducible ventricular tachycardia (P = 0.047), but the difference was not clinically significant.

CONCLUSION

Electrocardiographic characteristics of spontaneous nonsustained ventricular tachycardia do not predict which patients with coronary artery disease will have inducible sustained ventricular tachycardia.