Stroke after thrombolysis. Mortality and functional outcomes in the GUSTO-I trial. Global Use of Strategies to Open Occluded Coronary Arteries

Thrombolysis in elderly patients with acute myocardial infarction

The efficacy of thrombolytic therapy in the elderly remains a topic of ongoing debate. Although elderly patients account for a disproportionate amount of cardiovascular mortality, they have typically been underrepresented in randomized clinical trials. A meta-analysis of these trials suggests a survival benefit, albeit small, of thrombolytic therapy in the elderly. Thrombolytic therapy, in combination with either glycoprotein IIb/IIIa inhibitors or low-molecular weight heparin, poses an increased hazard in the elderly. Observational studies of thrombolytic therapy in the elderly portray a far worse outcome than the randomized clinical trials and raise the possibility of increased mortality. To date, no randomized trial has compared thrombolytic and primary coronary intervention in the elderly. However, multiple observational studies indicate a low risk of intracerebral hemorrhage and improved survival when a strategy of primary coronary intervention is employed. Future trials and observational studies should elucidate the ideal reperfusion strategy in the elderly.

Quality of life associated with visual loss: a time tradeoff utility analysis comparison with medical health states

PURPOSE

To assess the visual utility values of patients with ocular disease and to compare these values with those of patients with systemic health states

DESIGN

Cross-sectional utility value assessment.

METHODS

Consecutive patients with ophthalmic diseases were interviewed in a one-on-one fashion using a standardized time tradeoff utility value assessment form. These values were compared with utility values for systemic health states present in the literature.

INTERVENTION

None.

MAIN OUTCOME MEASURE

Time tradeoff utility value on a scale ranging from 1.0 (perfect visual health) to 0.0 (death). The ophthalmic patient groups were stratified into 4 visual groups dependent on the visual acuity in the better-seeing eye. The groups were as follows: group 1, 20/20 to 20/25; group 2, 20/30 to 20/50; group 3, 20/60 to 20/100; group 4, 20/200 to no light perception.

RESULTS

A total of 500 subjects were enrolled in the study. The mean utility values for the visually stratified groups were: group 1, 0.88; group 2, 0.81; group 3, 0.72; group 4, 0.61. Comparable respective systemic health state utility values for each of the ophthalmic groups were: diabetes mellitus, status after kidney transplantation, moderate stroke, and moderately severe stroke.

CONCLUSIONS

Visual loss is associated with a substantial and measurable diminution in quality of life. This diminution in quality of life can be directly compared with that induced by systemic health states.

Health care economic analyses and value-based medicine

Health care economic analyses are becoming increasingly important in the evaluation of health care interventions, including many within ophthalmology. Encompassed with the realm of health care economic studies are cost-benefit analysis, cost-effectiveness analysis, cost-minimization analysis, and cost-utility analysis. Cost-utility analysis is the most sophisticated form of economic analysis and typically incorporates utility values. Utility values measure the preference for a health state and range from 0.0 (death) to 1.0 (perfect health). When the change in utility measures conferred by a health care intervention is multiplied by the duration of the benefit, the number of quality-adjusted life-years (QALYs) gained from the intervention is ascertained. This methodology incorporates both the improvement in quality of life and/or length of life, or the value, occurring as a result of the intervention. This improvement in value can then be amalgamated with discounted costs to yield expenditures per quality-adjusted life-year ($/QALY) gained. $/QALY gained is a measure that allows a comparison of the patient-perceived value of virtually all health care interventions for the dollars expended. A review of the literature on health care economic analyses, with particular emphasis on cost-utility analysis, is included in the present review. It is anticipated that cost-utility analysis will play a major role in health care within the coming decade.

A meta-analysis of quality-of-life estimates for stroke

BACKGROUND

Researchers performing cost-effectiveness analyses often incorporate quality-of-life (QOL) estimates.

OBJECTIVE

To aid analysts, we performed a meta-analysis to estimate quality of life for minor, moderate, and major stroke and assessed the relative importance of study design characteristics in predicting the quality of life of patients with stroke.

METHODS

Through a systematic search we identified 20 articles reporting 53 unique QOL weights for stroke. Each article was read and QOL weights and study characteristics were recorded. We used a hierarchical linear model (HLM) to perform a meta-regression. The model included severity of stroke, elicitation method, respondents, and QOL scale bounds as explanatory variables.

RESULTS

Severity of stroke (p < 0.0001) and the bounds of the scale (p = 0.0015) were significant predictors of quality of life, while the elicitation method and respondents were not. Pooling QOL weights using the HLM model, we estimated a quality of life of 0.52 for major stroke, 0.68 for moderate stroke, and 0.87 for minor stroke if the time trade-off method is used to assess quality of life from community members when the scale bounds range from death to perfect health.

CONCLUSIONS

We found no systematic difference in stroke QOL weights depending on elicitation method or respondents. However, quality of life is sensitive to the bounds of the scale. Because the pooled QOL estimates reported here are based on a comprehensive review of the QOL literature for stroke, they should be of great use to researchers performing cost-utility analyses of interventions designed to prevent or treat stroke, or where stroke is a possible side effect of therapy.

Thrombolytic therapy

The therapeutic use of thrombolytic agents is the natural result of the increasing understanding of the pathophysiologic mechanisms underlying normal and deranged thrombosis and fibrinolysis. Plasminogen activators capable of increasing the production of plasmin exhibit considerable efficacy in the treatment of a variety of arterial and venous thrombotic disorders. The ideal thrombolytic agent has yet to be developed but the desired clinical result of rapid opening of the thrombosed vessel without reocclusion, without activation of systemic fibrinogenolysis, and without a risk of hemorrhage is well defined. Clinical studies clearly demonstrate that the addition of a variety of adjunctive agents to the available thrombolytics enhances benefit without inordinate risk. The addition of intravascular angioplasty and stenting to thrombolysis increases the potential long-term benefit. Newer thrombolytic agents and new protocols for the use of existing therapies offer the promise of saving many who would otherwise succumb to coronary or cerebral arterial thrombosis or to venous thromboembolism.

Ethics and consent to treat issues in acute stroke therapy

Consent to treat with thrombolytic therapy for acute ischemic stroke presents an ethical dilemma for hospitals, physicians, patients, and their families. This article presents four aspects of this controversial topic and provides recommendations for conditions that allow for ethical consent to treat.

Administration of glycoprotein IIb-IIIa inhibitors in patients with ST-segment elevation myocardial infarction

Patients with ST-segment elevation acute myocardial infarction require immediate reperfusion therapy. Reperfusion therapy can be provided by either pharmacologic or mechanical means. Pharmacologic reperfusion therapy consists of administering fibrinolytics, whereas mechanical reperfusion consists of performing percutaneous intervention, usually with stent placement. Each approach has been shown to decrease mortality, but each has disadvantages in establishing flow in the infarct-related artery. Regardless of the approach, during an acute myocardial infarction, activation and externalization of glycoprotein (GP) IIb-IIIa receptors occur on the surface of platelets. The GP IIb-IIIa inhibitors block the binding of fibrinogen to these platelet receptors. These inhibitors have been investigated in combination with both reperfusion strategies. The goal of adding GP IIb-IIIa inhibitor therapy to either reperfusion approach is to obtain better early, complete, and sustained reperfusion. Subsequently, this should lead to better clinical outcomes for patients with ST-segment elevation acute myocardial infarction. Although no mortality benefit has been seen with the addition of GP IIb-IIIa inhibitor therapy, ischemic complications have been reduced significantly.

Drug-induced iatrogenic intraparenchymal hemorrhage

Intracerebral hemorrhage is bleeding into the brain parenchyma with possible extension into the ventricles and subarachnoid space. Each year, approximately 37,000 to 52,400 people suffer from intraparenchymal hemorrhage (IPH) in the United States. This rate is expected to rise dramatically in the next few decades as a result of the increasing age of the population and a change in racial demographics. IPH accounts for 8% to 13% of all stroke cases and is associated with the highest mortality rate.

The development and role of predictive instruments in acute coronary events: improving diagnosis and management

The diagnosis and management of acute myocardial infarction and unstable angina pectoris are frequent challenges for emergency department staff. Strategies must quickly and accurately identify all patients requiring admission, monitoring, and reperfusion therapy to maximize outcomes without overdiagnosing. The Acute Cardiac Ischemia Time-Insensitive Predictive Instrument and the Thrombolytic Predictive Instrument are two decision-support tools designed to address this need. The instruments have been shown to improve some measures of the appropriateness of and time to emergency department triage. Prospective trials will be completed soon that will examine their effects on morbidity and mortality.

Use of reperfusion therapies in elderly patients with acute myocardial infarction

Almost one-third of patients with acute myocardial infarction (AMI) are aged >75 years, and this proportion is expected to increase as the population ages. Mortality and complication rates are particularly high in the elderly, yet reperfusion therapies, including thrombolysis and primary percutaneous transluminal coronary angioplasty (PTCA), are under-utilised among eligible patients. There is a concern, whether real or perceived, that the risks of such therapies may outweigh the potential benefits. Presently, there are no randomised clinical trials of thrombolytic therapy in the elderly that definitively assess its efficacy in patients aged >75 years. In the meta-analysis of randomised trials by the Fibrinolytic Therapy Trialists, thrombolysis was associated with a mortality reduction among patients aged >75 years, though this reduction did not meet formal statistical significance. Because the point estimates for mortality reduction were in the direction that favoured use of thrombolytic therapy, the American Heart Association/American College of Cardiology AMI guidelines recommend thrombolysis as a Class 2a therapy in this age group. Observational studies using data from the Cooperative Cardiovascular Project database and the National Registry of Myocardial Infarction have recently cast some doubt on the benefit of thrombolysis among the elderly, but definitive answers from a randomised trial are still lacking. Meanwhile, primary PTCA, which has been compared to thrombolysis in both trial and observational settings, appears to offer the mortality benefit of reperfusion with lower stroke rates. Since primary PTCA is not widely available, efforts must be made to maximise available therapies in the elderly. Early diagnosis is essential, as is prompt reperfusion among eligible patients, since delay is so strongly associated with mortality with both thrombolysis and PTCA. Finally, newer, more fibrin-specific thrombolytics may decrease the bleeding risk associated with thrombolytic therapy.

Thrombin-specific anticoagulation with bivalirudin versus heparin in patients receiving fibrinolytic therapy for acute myocardial infarction: the HERO-2 randomised trial

BACKGROUND

The combination of fibrinolytic therapy and heparin for acute myocardial infarction fails to achieve reperfusion in 40-70% of patients, and early reocclusion occurs in a substantial number. We did a randomised, open-label trial to compare the thrombin-specific anticoagulant, bivalirudin, with heparin in patients undergoing fibrinolysis with streptokinase for acute myocardial infarction.

METHODS

17073 patients with acute ST-elevation myocardial infarction were randomly assigned an intravenous bolus and 48-h infusion of either bivalirudin (n=8516) or heparin (n=8557), together with a standard 1.5 million unit dose of streptokinase given directly after the antithrombotic bolus. The primary endpoint was 30-day mortality. Secondary endpoints included reinfarction within 96 h and bleeding. Strokes and reinfarctions were adjudicated by independent committees who were unaware of treatment allocation. Analysis was by intention to treat.

FINDINGS

By 30 days, 919 patients (10.8%) in the bivalirudin group and 931 (10.9%) in the heparin group had died (odds ratio 0.99 [95% CI 0.90-1.09], p=0.85). The mortality rates adjusted for baseline risk factors were 10.5% for bivalirudin and 10.9% for heparin (0.96 [0.86-1.07], p=0.46). There were significantly fewer reinfarctions within 96 h in the bivalirudin group than in the heparin group (0.70 [0.56-0.87], p=0.001). Severe bleeding occurred in 58 patients (0.7%) in the bivalirudin group versus 40 patients (0.5%) in the heparin group (p=0.07), and intracerebral bleeding occurred in 47 (0.6%) versus 32 (0.4%), respectively (p=0.09). The rates of moderate and mild bleeding were significantly higher in the bivalirudin group than the heparin group (1.32 [1.00-1.74], p=0.05; and 1.47 [1.34-1.62], p<0.0001; respectively). Transfusions were given to 118 patients (1.4%) in the bivalirudin group versus 95 patients (1.1%) in the heparin group (1.25 [0.95-1.64], p=0.11).

INTERPRETATION

Bivalirudin did not reduce mortality compared with unfractionated heparin, but did reduce the rate of adjudicated reinfarction within 96 h by 30%. Small absolute increases were seen in mild and moderate bleeding in patients given bivalirudin. Bivalirudin is a new anticoagulant treatment option in patients with acute myocardial infarction treated with streptokinase.

Safety of the weight-adjusted dosing regimen of tenecteplase in the ASSENT-Trial

The results of the ASsessment of Safety and Efficacy of a New Thrombolytic agent (ASSENT-2) trial revealed that tenecteplase (TNK) is equivalent to tissue plasminogen activator (t-PA) for treating myocardial infarction. Because careful consideration of safety is important with all agents, including the newer bolus therapies, and across a range of doses, this study evaluated the safety of TNK compared with t-PA across a range of weight and dose categories. The 5 doses of TNK ranged from 30 to 50 mg and were adjusted for estimated weight. Rates of death and intracranial hemorrhage were determined among patients receiving TNK and t-PA in ASSENT-2, stratified by categories of estimated weight corresponding to each TNK dose. Respective rates of death with TNK versus t-PA were not significantly different in any estimated weight category: <60 kg (12.54% vs 11.46%), 60 to 69 kg (8.22% vs. 8.97%), 70 to 79 kg (5.57% vs 5.48%), 80 to 89 kg (4.66% vs 5.36%), and > or =90 kg (4.91% vs. 3.96%, all p > or =0.26). Respective rates of intracranial hemorrhage were also not significantly different: <60 kg (2.20% vs. 2.29%), 60 to 69 kg (0.97% vs. 1.33%), 70 to 79 kg (1.15% vs. 1.10%), 80 to 89 kg (0.73% vs 0.49%), and > or =90 kg (0.47% vs 0.47%, all p > or =0.33). Adjustment for small baseline differences in this randomized sample did not change the results. Thus, across the range of estimated weight categories corresponding to each TNK dose, TNK is as safe and effective as t-PA.

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

OBJECTIVES

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

BACKGROUND

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

METHODS

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

RESULTS

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

CONCLUSIONS

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

Issues in the assessment of the safety and efficacy of tenecteplase (TNK-tPA)

While thrombolytic agents have demonstrated improved mortality over the use of placebo, this has come at the expense of bleeding complications such as intracranial hemorrhage (ICH). Tenecteplase (TNK-tPA) is a novel thrombolytic agent engineered to improve upon the ease of use and safety of alteplase (t-PA). Given its longer half-life, TNK-tPA can be administered as a single bolus. The dosing of TNK-tPA has been weight optimized to enhance both safety and efficacy outcomes. Weight-optimized TNK-tPA dosing requires body weight estimation, which may introduce the potential for medication error. However, data from TNK-tPA clinical trials suggest that body weight estimates can err by up to 20 kg (44 lb) without an increased risk of ICH or death. Furthermore, the results of TNK-tPA clinical trials showed that even at the highest weight-optimized dosage of 50 mg, ICH rates were among the lowest reported in clinical trials of thrombolytics for acute myocardial infarction. In elderly female patients of low body weight, the use of weight-optimized TNK-tPA lowered the risk of ICH compared with the use of t-PA, expanding the potential use of thrombolytics to this high-risk patient population. Tenecteplase has demonstrated clinical equivalence to t-PA, but with a wider therapeutic margin of safety.

New heparin dosing recommendations for patients with acute coronary syndromes

Despite major innovations in antithrombotic and antiplatelet therapy, unfractionated intravenous heparin is widely used to treat acute coronary syndromes. Recommendations for unfractionated heparin dosing in acute myocardial infarction and unstable angina have been issued in two recent American College of Cardiology/American Heart Association guidelines. An initial heparin bolus of 60 U/kg (maximum, 4000 U) followed by a 12-U/kg/h infusion (maximum 1000 U/h) is recommended with alteplase for ST-elevation myocardial infarction. When intravenous heparin is administered for myocardial infarction with non-ST elevation and unstable angina, an initial bolus of 60 to 70 U/kg (maximum, 5000 U) followed by a 12- to 15-U/kg/h infusion is recommended. The goal is to achieve an activated partial thromboplastin time of 50 to 70 seconds. Here, we review these new dosing regimens and explain the rationale for their use. We also review the risk of bleeding with heparin, especially when administered concurrently with aspirin, thrombolytic agents, and glycoprotein IIb/IIIa antagonists, and the relationship between activated partial thromboplastin time and cardiac events.

Consequences of overutilization and underutilization of thrombolytic therapy in clinical practice. TRACE Study Group. TRAndolapril Cardiac Evaluation

OBJECTIVES

The aim of this study was to evaluate the consequences, measured as mortality and in-hospital stroke, of the use of thrombolytic therapy among patients with acute myocardial infarction (AMI), who do not fulfill accepted criteria or who have contraindications to thrombolytic therapy (i.e., overutilization) and among patients who are withheld thrombolytic treatment despite fulfilling indications and having no contraindications (i.e., underutilization).

BACKGROUND

The implementation of treatment with thrombolysis in clinical practice is not in accordance with the accepted criteria from randomized studies. The consequence has been over- and underutilization of thrombolytic therapy among patients with AMI in clinical practice. The outcome of overutilization of thrombolytic therapy has not been described previously.

METHODS

We examined 6,676 consecutive patients admitted to the hospital with an AMI and recorded characteristics, in-hospital complications and long-term mortality.

RESULTS

Overall, 41% of the patients received thrombolytic therapy. Thrombolytic therapy was underutilized in 14.3% and overutilized in 12.9% of the patients. The use of thrombolytic therapy was associated with reduced mortality in every subgroup examined, including patients without an accepted indication, with an accepted indication and in patients with prior stroke. The risk ratio of in-hospital stroke was not increased in connection with thrombolytic therapy, not even in patients with prior stroke (relative risk = 0.237, 95% confidence interval: 0.031 to 1.810, p = 0.17).

CONCLUSIONS

With the large benefit known to be associated with thrombolytic therapy and the favorable result of thrombolytic therapy in patients with contraindications observed in this study, we conclude that a formal evaluation of thrombolytic therapy in wider patient categories is warranted.

Lower-dose heparin with fibrinolysis is associated with lower rates of intracranial hemorrhage

BACKGROUND

The optimal heparin dose as an adjunct to fibrinolysis and its role in causing intracranial hemorrhage (ICH) is unclear.

METHODS

We reviewed the heparin regimens and rates of ICH in 3 sets of recent fibrinolytic trials: (1) studies with accelerated recombinant tissue plasminogen activator (TPA, alteplase) plus intravenous heparin, in which the heparin regimen was changed during the course of the trial; (2) phase III trials with accelerated TPA plus intravenous heparin; and (3) trials of new single-bolus fibrinolytic agents.

RESULTS

Lower rates of ICH were observed among studies of accelerated TPA that reduced the heparin dose mid-trial (TIMI 9A --> 9B: 1.87% --> 1.07%, GUSTO-IIa --> IIb: 0.92% --> 0.71%, TIMI 10B: 2.80% --> 1.16%). Rates of ICH with accelerated TPA gradually increased from GUSTO-I (0.72%) in 1990 to 1993 to ASSENT-2 (0.94%) in 1997 to 1998. However, this trend was reversed in InTIME-II, which used the lowest heparin dose and most aggressive activated partial thromboplastin time monitoring and observed an ICH rate of 0.64% with accelerated TPA. Lower ICH rates were also observed when the heparin dose was reduced with single-bolus tenecteplase (TNK-TPA) and lanoteplase.

CONCLUSIONS

Nonrandomized comparisons with accelerated TPA suggest that lower doses of intravenous heparin are associated with lower rates of ICH. This observation also appears to apply to single-bolus TNK-TPA and novel plasminogen activator. A lower-dose, weight-adjusted heparin regimen (60 U/kg bolus; maximum, 4000 U; 12 U/kg per hour infusion; maximum, 1000 U/h) with earlier monitoring of activated partial thromboplastin time is currently recommended in the revised American College of Cardiology/American Heart Association myocardial infarction guidelines and should be used in clinical practice.

NONARRHYTHMIC COMPLICATIONS OF ACUTE MYOCARDIAL INFARCTION

Complications of acute myocardial infarction can be categorized as nonarrhythmic or arrhythmic; the latter is discussed elsewhere. Patients are at risk for a number of potentially serious or fatal complications during or after the acute infarction phase. These include shock, left ventricular free wall rupture, rupture of the interventricular septum, papillary muscle rupture, ventricular pseudoaneurysm, and stroke. Right ventricular infarction, which is typically associated with inferior myocardial infarction, will also be discussed.

Can myocardial infarction be rapidly identified in emergency department patients who have left bundle-branch block?

STUDY OBJECTIVES

Fibrinolytic therapy is recommended for patients who have chest pain and left bundle-branch block (LBBB). However, the presence of baseline ECG abnormalities makes early accurate identification of acute myocardial infarction (AMI) difficult. The predictive ability of clinical and ECG variables for identifying patients with LBBB and AMI has not been well studied. We sought to determine the prevalence and predictors of myocardial infarction among patients presenting to the emergency department with LBBB on the initial ECG who were evaluated for myocardial infarction.

METHODS

All patients presenting to the ED were prospectively risk stratified on the basis of clinical and historical variables. ECGs from patients with LBBB were compared retrospectively with previously published criteria for identification of AMI. The ability of a new LBBB to predict AMI was also determined.

RESULTS

Twenty-four (13%) of the 182 patients with LBBB had AMI. Clinical and historical variables were similar in patients with and without AMI. A new LBBB had a sensitivity of 42% and a specificity of 65%. The presence of concordant ST-segment elevation or depression had specificities and positive predictive values of 100%; however, sensitivities were only 8% and 17%, respectively. The best diagnostic criterion was the presence of concordant ST-segment elevation or depression on the ECG or an initially elevated creatine kinase MB (sensitivity, 63%; specificity, 99%).

CONCLUSION

ECG criteria for identifying patients with AMI and LBBB identify only a small minority of patients with AMI. Treating all patients with LBBB and chest pain with fibrinolytics would result in treatment of a significant number of patients without AMI.

Determination of a weight-adjusted dose of TNK-tissue plasminogen activator

BACKGROUND

TNK-tissue plasminogen activator (TNK-tPA) is a potent new thrombolytic agent for treatment of acute myocardial infarction. TNK-tPA was evaluated in 4214 patients in two dose-ranging trials (Thrombolysis in Myocardial Infarction [TIMI] 10B and Assessment of the Safety and Efficacy of a New Thrombolytic Agent [ASSENT] I). This article describes the rationale for the weight-adjusted dosing regimen of TNK-tPA that was selected for evaluation in the large phase III clinical trial ASSENT II.

METHODS

Weight-based analyses were conducted with data from both the angiographic TIMI 10B trial, which compared TNK-tPA in doses of 30 mg, 40 mg, and 50 mg with the accelerated regimen of tPA in 889 patients, and the ASSENT I trial, which evaluated the safety of TNK-tPA in doses of 30 mg, 40 mg, and 50 mg in 3301 patients. Graphic and statistical analytic methods were used to assess relationships between weight and efficacy or safety measurements.

RESULTS

The plasma clearance, initial plasma concentrations, and plasma steady-state volume of distribution all increased with decreasing body weight (all P<.001). The corrected TIMI frame count decreased (flow was faster) (P =.001) and the TIMI grade 3 flow increased with an increasing weight-standardized dose of TNK-tPA (P<.008). Mortality was inversely related to dose, but this relationship was not statistically significant. There was no clear relationship between intracranial hemorrhage and dose and weight. Serious bleeding events increased with increasing weight-standardized dose (P<.02).

CONCLUSIONS

On the basis of these analyses, a weight-adjusted dosing regimen was devised for TNK-tPA that included five dosing increments and was based on a target weight-standardized dose of 0.53 mg/kg.

Fibrin specificity and procoagulant effect related to the kallikrein-contact phase system and to plasmin generation with double-bolus reteplase and front-loaded alteplase thrombolysis in acute myocardial infarction

This study was undertaken to compare the effects of reteplase and alteplase regimens on hemostasis and fibrinolysis in acute myocardial infarction (AMI). Thrombolytic treatment in patients with AMI is hampered by paradoxical procoagulant effects that favor early reocclusion. In vivo data comparing this effect and the fibrin specificity of double-bolus reteplase and front-loaded alteplase regimens are not available. In a prospective, randomized study, 50 patients with AMI were either treated with double bolus (10 + 10 U) reteplase or with front-loaded alteplase (up to 100 mg) within 6 hours of symptom onset. Thirty apparently healthy persons served as controls. Molecular markers of coagulation and fibrinolysis were serially examined for up to 5 days. Paradoxical thrombin activation at 3 hours after initiation of therapy was comparable between reteplase and alteplase. Reteplase (65 +/- 5 U/L) and alteplase (72 +/- 8 U/L) caused significantly elevated kallikrein activity at 3 hours after adminstration (p <0.01 vs controls 30 +/- 1 U/L). Fibrin specificity was less for reteplase (p <0.05) with a decrease in fibrinogen at 3 hours to 122 +/- 27 mg/dl versus 224 +/- 28 mg/dl for alteplase (p <0.01 and p <0.05 vs controls). D-Dimer levels at 3 hours were higher (p <0.05) after reteplase (5,459 +/- 611 ng/ml) versus alteplase (3,445 +/- 679 ng/ml) (both p <0.01 vs controls 243 +/- 17 ng/ml). Plasmin generation (plasmin-antiplasmin complexes) was significantly (p <0.01) increased at 3 hours with both regimens to 27,079 +/- 3,964 microg/L (reteplase) and 19,522 +/- 2,381 microg/L (alteplase). The data from 3 hours after start of thrombolytic therapy proved less marked fibrin specificity of the reteplase regimen (in vivo) compared with front-loaded alteplase. Both regimens have a moderate procoagulant effect without differences in activation of the kallikrein system.

One thousand health-related quality-of-life estimates

OBJECTIVE

Analysts performing cost-effectiveness analyses often do not have the resources to gather original quality-of-life (QOL) weights. Furthermore, variability in QOL for the same health state hampers the comparability of cost-effectiveness analyses. For these reasons, opinion leaders such as the Panel on Cost-Effectiveness in Health and Medicine have called for a national repository of QOL weights. Some authors have responded to the call by performing large primary studies of QOL. We take a different approach, amassing existing data with the hope that it will be combined responsibly in meta-analytic fashion. Toward the goal of developing a national repository of QOL weights to aid cost-effectiveness analysts, 1,000 health-related QOL estimates were gathered from publicly available source documents.

METHODS

To identify documents, we searched databases and reviewed the bibliographies of articles, books, and government reports. From each document, we extracted information on the health state, QOL weight, assessment method, respondents, and upper and lower bounds of the QOL scale. Detailed guidelines were followed to ensure consistency in data extraction.

RESULTS

We identified 154 documents yielding 1,000 original QOL weights. There was considerable variation in the weights assessed by different authors for the same health state. Methods also varied: 51% of authors used direct elicitation (standard gamble, time tradeoff, or rating scale), 32% estimated QOL based on their own expertise or that of others, and 17% used health status instruments.

CONCLUSIONS

This comprehensive review of QOL data should lead to more consistent use of QOL weights and thus more comparable cost-effectiveness analyses.

Cost-effectiveness of 3-hydroxy-3-methylglutaryl coenzyme A reductase inhibitor therapy in older patients with myocardial infarction

BACKGROUND

3-Hydroxy-3-methylglutaryl coenzyme A reductase inhibitor (statin) therapy has proven efficacy in reducing the rate of coronary and cerebrovascular events in patients 75 years of age or younger with a history of myocardial infarction. However, in patients older than 75 years of age, the efficacy and potential cost-effectiveness of statins are unknown.

OBJECTIVE

To estimate the incremental cost-effectiveness of statin therapy compared with usual care in patients 75 to 84 years of age with previous myocardial infarction.

DESIGN

Cost-effectiveness analysis.

DATA SOURCES

Published data from cohort studies.

TARGET POPULATION

Patients 75 to 84 years of age with a history of myocardial infarction.

TIME HORIZON

Lifetime.

PERSPECTIVE

Societal.

INTERVENTION

Statin therapy.

OUTCOME MEASURES

Life expectancy, quality-adjusted life expectancy, and incremental cost-effectiveness.

RESULTS OF BASE-CASE ANALYSIS

The incremental cost-effectiveness of statin therapy compared with usual care in patients 75 to 84 years of age with previous myocardial infarction was $18800 per quality-adjusted life-year (QALY).

RESULTS OF SENSITIVITY ANALYSIS

On the basis of a probabilistic sensitivity analysis, there is a 75% chance that statin therapy costs less than $39800 per QALY compared with usual care. If the cost of statin therapy and efficacy of statin therapy at reducing myocardial infarction were set to their most favorable values, statin therapy cost $5400 per QALY; if cost and efficacy were set to their least favorable values, statin therapy cost $97800 per QALY.

CONCLUSIONS

The cost-effectiveness ratios of statin therapy in older patients with previous myocardial infarction are reasonable under a wide variety of assumptions about drug efficacy, drug cost, and rates of cardiac and cerebrovascular events. Pending results of randomized, controlled trials of secondary prevention in patients in this age group, statin therapy seems to be as cost-effective as many routinely accepted medical interventions in this setting.

Intracerebral hemorrhage

Intracerebral hemorrhage (ICH) represents a significant fraction of all strokes and causes a disproportionate amount of stroke related morbidity and mortality, especially in young blacks. While diagnosis of this disorder has greatly improved in the CT era, morbidity and mortality remain essentially unchanged. Not one currently utilized therapeutic modality has been clearly associated with a beneficial effect on long term outcome in small prospective randomized treatment trials for ICH. In spite of the lack of scientific data regarding therapy, patients often require aggressive medical and surgical intervention because of the life-threatening presentation of many patients. Recent clinical and experimental ICH research has identified a number of potentially effective new therapeutic strategies, and time to treatment is likely to be very important as it is for ischemic stroke. Large prospective, randomized, placebo controlled trials to examine the judicious application of current therapeutic modalities, and to investigate the potential benefit of proposed new treatment modalities, are long overdue.

Bridging the gap with new strategies in acute ST elevation myocardial infarction: bolus thrombolysis, glycoprotein IIb/IIIa inhibitors, combination therapy, percutaneous coronary intervention, and "facilitated" PCI

Achieving early reperfusion with thrombolytic agents or primary percutaneous coronary intervention (PCI) in patients with acute myocardial infarction (AMI) is the cornerstone of current therapy. Two advances in pharmacologic therapy are: (1) bolus thrombolysis, which simplifies therapy, reduces door-to-needle time, and reduces the potential for medication errors, and (2) Low-dose fibrinolytic therapy combined with a glycoprotein (GP) IIb/IIIa inhibitor which can achieve higher rates of reperfusion than fibrinolytic therapy alone. In addition, the IIb/IIIa inhibitor as part of the reperfusion regimen will support any acute-phase interventions that are performed. The combination of fibrinolytic therapy and GP IIb/IIIa inhibition to "facilitate" PCI is being examined in TIMI-14, SPEED, and GUSTO IV. Early findings in the SPEED trial have shown promising results with "facilitated" PCI when patency is achieved before PCI is attempted. Results of these trials will further define the role of combination therapy in facilitating mechanical interventions.

Combination therapy for acute myocardial infarction: fibrinolytic therapy and glycoprotein IIb/IIIa inhibition

Reperfusion with a regimen of fibrinolytic therapy, aspirin, and unfractionated heparin is limited by a less than desirable reperfusion rate, an excessive reocclusion rate, a dose-limiting intracranial hemorrhage rate, and a competitive posture relative to direct coronary angioplasty. Only 50% to 60% of patients achieve early Thrombolysis in Myocardial Infarction grade 3 flow within 90 minutes with the most effective thrombolytic regimens. Even after initial reperfusion is achieved, transient and permanent reocclusion occurs too often and is associated with a high mortality rate. As more older patients are being treated, intracranial hemorrhage is becoming more common. Finally, the risk of bleeding and procedural failure has been high in patients who received an acute percutaneous interventional procedure shortly after treatment with fibrinolytic therapy. Early studies combining full-dose fibrinolytic treatment and glycoprotein IIb/IIIa inhibitors have been promising with regard to overcoming these limitations, but concern about bleeding has hindered this strategy. Several recent trials have evaluated full-dose abciximab with reduced-dose fibrinolytic therapy and have yielded promising results. The complementary nature of the results from different trials is striking, with substantial evidence that approximately half the conventional dose of fibrinolytic therapy combined with full-dose glycoprotein IIb/IIIa inhibition with abciximab achieves high rates of grade 3 flow and excellent clinical outcomes. This approach will now be tested in a large-scale mortality trial.

Cerebral aneurysm rupture after r-TPA thrombolysis for acute myocardial infarction

BACKGROUND

Intracranial hemorrhage is the most dreaded risk of thrombolytic therapy for acute myocardial infarction because of the high mortality and disability rates associated with this complication. Brain structural lesions may predispose a patient to bleeding. To date, aneurysm rupture has not been described as a complication of such therapy.

CASE DESCRIPTION

A 66-year-old hypertensive woman was admitted because of chest pain. Myocardial infarction was diagnosed and fibrinolytic therapy with recombinant tissue plasminogen activator (r-TPA) was initiated. Eight hours after admission she became unconscious. Brain computed tomography scan showed subarachnoid hemorrhage, and a cerebral arteriography showed an anterior communicating artery aneurysm. Because of her poor clinical condition treatment was postponed. Death occurred 7 days later because of multiorgan failure.

CONCLUSIONS

Cerebral aneurysms should be considered as a possible contributing factor to intracranial bleeding after thrombolytic therapy.

Percutaneous transluminal angioplasty for the treatment of complete arterial occlusion after retrograde cardiac catheterization in infancy

Nine patients with arterial thrombosis were treated with transcatheter recanalization and subsequent balloon dilation of the occluded vessel. Repeat angiography or duplex sonography 3 to 14 months after intervention showed completely patent arteries without restenosis in 7 patients; there was residual narrowing of the vessel in the remaining 2 patients.

Delayed thrombolytic treatment of older patients with acute myocardial infarction

OBJECTIVE

To determine demographic and clinical factors associated with delayed thrombolysis in patients with acute myocardial infarction.

DESIGN

A retrospective cohort.

SETTING

37 Minnesota hospitals during the time periods October 1992-July 1993 and July 1995-April 1996.

PATIENTS

We reviewed the medical records of 776 older patients aged 65 or older hospitalized with an admission diagnosis of acute myocardial infarction, suspected acute myocardial infarction, or rule-out acute myocardial infarction, who were treated with a thrombolytic agent.

MEASUREMENT

We used multivariate logistic regression models to examine the association between selected study characteristics and time between hospital presentation and administration of thrombolytic treatment. Early thrombolysis was defined as less than 60 minutes after hospital presentation and late thrombolysis as 60+ minutes.

RESULTS

Of 776 study patients, 57.5% (n = 446) received early thrombolysis. Of the remaining 330 patients receiving late treatment, 12.1% (n = 94) were thrombolyzed more than 2 hours after hospital presentation. After controlling for other factors, the odds of delayed thrombolysis among patients aged 75 or older were 1.48 compared with younger individuals (95% CI, 1.17-1.88). The odds of delayed thrombolysis among patients with severe comorbidity were 1.46 (95% CI, 1.10-1.94) compared with individuals without severe comorbidity. Predictors of early thrombolytic treatment included hospital arrival via emergency transport (ORdelay = 0.46; 95% CI, 0.34-0.63) and chest discomfort at admission (ORdelay = 0.40; 95% CI, 0.18-0.86).

CONCLUSIONS

The present study indicates that patients of advanced age and with severe comorbidity are more likely to experience delayed thrombolytic treatment after hospital presentation. These are the patients who suffer the highest morbidity from acute myocardial infarction and for whom expeditious treatment may enhance therapeutic benefit.

Quality of life after cerebrovascular stroke: a systematic study of patients' preferences for different functional outcomes

OBJECTIVES

To elicit valid quality of life estimates and the highest acceptable treatment risk of different outcomes after stroke. This is a prerequisite for rational medical decision-making, especially when considering treatments like thrombolysis.

SUBJECTS

Healthy people, non-stroke medical patients and stroke survivors aged 20-84 years (n = 158)

INTERVENTIONS

Subjects were interviewed by a physician using three different methods ('standard gamble', 'time trade-off' and 'direct scaling') supported by an interactive computer program.

MAIN OUTCOME MEASURES

We measured utility, a numerical value ranging from 0.00 (death) to 1.00 (perfect health), representing the strength of the patient's preference for an outcome. When using the standard gamble method, risk is also introduced into the measurement.

RESULTS

People's preferences for stroke outcomes varied widely, and the estimates were influenced by assessment method. We found that previous stroke, marital status and age were the only independent variables influencing the utility given. Subjects in our population over the age of 45 were very comparable to the real population at risk for acute stroke regarding these three variables, and they assigned a median utility of 0.91 (10th percentile, 0.65; 90th percentile, 0.99) to a minor stroke and 0.61 (10th percentile, 0.08; 90th percentile, 0.95) to a major stroke using the standard gamble method.

CONCLUSIONS

Most people do not feel that suffering from stroke is an overwhelming catastrophe and they do not accept treatment options with very high risks.

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.

Cardiac complications in the intensive care unit

Advances in the care of critically ill patients has been startling, especially in patients with acute coronary syndromes. With new therapies and procedures, however, have come new complications. On balance, our patients are better off, but the stakes are now higher and the complications more serious. The need for constant vigilance has never been greater.

Safety assessment of single-bolus administration of TNK tissue-plasminogen activator in acute myocardial infarction: the ASSENT-1 trial. The ASSENT-1 Investigators

BACKGROUND

To evaluate the safety of several doses of a new thrombolytic, TNK tissue-plasminogen activator (tPA), given as a single bolus to patients with acute myocardial infarction.

METHODS AND RESULTS

A total of 3235 patients were given TNK-tPA: 1705 received 30 mg, 1457 received 40 mg, and 73 received 50 mg. The 50-mg dose was discontinued and replaced by 40 mg because of increased bleeding observed in the Thrombolysis In Myocardial Infarction (TIMI)-10B study, the phase II angiographic efficacy trial conducted in parallel with this study. The total stroke rate at 30 days in the trial was 1.5%. An intracranial hemorrhage was observed in 25 patients (0.77%): 16 in the 30-mg group (0.94%) and 9 in the 40-mg group (0.62%). No strokes occurred in the 73 patients treated with 50 mg TNK-tPA. In patients treated within 6 hours after symptom onset the rates of intracranial hemorrhage were 0.56% (30 mg TNK-tPA) and 0.58 (40 mg TNK-tPA). Death, death or nonfatal stroke, or severe bleeding complications occurred in a low proportion of patients: 6.4%, 7.4%, and 2.8%, respectively, without significant differences among the treatment groups.

CONCLUSIONS

The overall safety profile of a single bolus of 30 to 50 mg TNK-tPA is comparable to that of accelerated r-tPA observed in other large trials. The safety data from this trial and the patency data of TIMI-10B were the basis for a decision to conduct a large phase III mortality trial comparing weight-adjusted single-bolus TNK-tPA with accelerated r-tPA (ASSENT-2).

Update on mechanical revascularization in acute myocardial infarction: which role and when?

Mechanical revascularization in the acute myocardial infarction by primary angioplasty has several advantages over thrombolytic therapy. The short-term patency rates of the infarct-related artery range from 95 to 99% and a normal flow is achieved in more than 90% of the cases. This prompt and effective reperfusion is probably responsible for the improved prognosis with primary angioplasty. The better outcome after primary angioplasty is observed both in low- and in high-risk patients, in all ages and in patients presenting late (>6 h) after the chest pain. Pooled analysis of randomized studies, show that primary angioplasty as compared to thrombolysis, has a lower incidence of death, stroke and reinfarction. Additional advantages of primary PTCA include the possibility of reperfusion in patients in whom lysis is contraindicated or less effective (e.g. patients in cardiogenic shock, or with prior coronary artery bypass surgery) and the ability to provide prognostic information helpful in the patient triage. Thus, primary PTCA results in better outcome than thrombolysis when performed in centers with success rates comparable to those achieved in the randomized trials. Further studies are still needed to assess its long-term efficacy. Several randomized trials are underway to assess the role of stents and the use of more potent antiplatelet drugs, as the GPIIb/IIIa receptor blockers, in adjunct to balloon angioplasty in the treatment of acute myocardial infarction.

Risk factors for intracranial hemorrhage in adults on extracorporeal membrane oxygenation

OBJECTIVE

Intracranial hemorrhage is a recognized complication in neonates and infants on extracorporeal membrane oxygenator support and various risk factors associated with this have been defined. The prevalence and risk factors associated with intracranial hemorrhage in adults on extracorporeal membrane oxygenator support are unknown and this study was performed to define these factors.

METHODS

A retrospective study of adults supported with extracorporeal membrane oxygenators at a single institution between January 1992 and December 1996 was performed. Age, gender, weight, body surface area, renal function, anticoagulation, coagulation variables, blood flow, arterial pressure, arterial cannulation sites, duration of support, extracranial bleeding, native cardiac function and presence of intracranial microemboli were analyzed to determine the risk factors for intracranial hemorrhage.

RESULTS

Fourteen out of 74 adults on extracorporeal membrane oxygenator support had intracranial hemorrhage (18.9%). An increased risk of intracranial hemorrhage showed a positive correlation with female gender (P = 0.02, odds ratio 6.5), use of heparin (P = 0.05, odds ratio 8.5), creatinine greater than 2.6 mg/ dl (P = 0.009, odds ratio 6.5), need for dialysis (P = 0.03, odds ratio 4.3) and thrombocytopenia (P = 0.007, odds ratio 18.3). Diminishing renal function and the need for dialysis were associated with increasing duration of support. Multivariable logistic regression showed female gender and thrombocytopenia, especially with platelet counts less than 50000 cells/mm3 to be the most important predictors of intracranial hemorrhage. Intracranial hemorrhage was associated with a mortality of 92.3% compared with a mortality of 61% in those without intracranial hemorrhage (P = 0.027).

CONCLUSION

Intracranial hemorrhage is a significant complication in adults on extracorporeal membrane oxygenator support. Judicious management of anticoagulation, prevention of renal failure and aggressive correction of thrombocytopenia may help to lower the risk of intracranial hemorrhage in adults on extracorporeal membrane oxygenator support.

Coronary heart disease. Stable and unstable syndromes

CHD in the elderly population will continue to be a source of major concern because of the increasing costs entailed and uncertainties about how the widespread array of diagnostic and therapeutic interventions, often expensive and sometimes hazardous, should be applied. Financial, political, and health policy decisions will continue to occupy much attention, but it is likely that philosophic considerations about aging and death, both from the individual and the societal perspective, will be of paramount importance of deciding how the substantial resources available to the elderly will be used. Randomized, controlled trials are unlikely to play a major role in resolution of management dilemmas in the elderly because of the extraordinary heterogeneity in this population. Registries (databases) involving carefully prospectively collected key variables are likely to be a more effective approach. Critical characterization of complications of procedures, adverse drug reactions, and collection of follow-up data on functional status are among the critical questions, and these can be answered by registry studies. Algorithms and clinical rules developed in younger cohorts are not directly transferable to the elderly cardiovascular patients, further emphasizing the need for prospectively collected, syndrome-specific data. Treatments convincingly demonstrated to reduce mortality in absolute terms more in the elderly than in the young are underused. The heterogeneity of aging emphasizes the wide variability in patients' ability to withstand the stress of procedures and complications of disease and makes clear the need to consider physiologic reserve and biologic age rather than chronology. With better characterization of biologic age and physiologic reserve, more precise estimates of outcomes of therapies and interventions can be made, and patients can be given better information and with their families have more realistic expectations. Better-informed decisions will result. Biologic age will be multifactorial, involving cognitive, emotional, physical, and nutritional attributes as well as specific organ function (lung, kidney, liver) because no single feature can characterize the total elderly patient. The concept of competing risks among the cardiovascular disease being treated, comorbidity, risks of study, and life expectancy will evolve because even the most successful therapy will have limited effect on longevity in the very old. Although important research at the cellular and molecular level will characterize and provide better understanding of the aging process, it is not likely that this basic information will be immediately useful in the management of the large number of elderly patients with major cardiovascular disease. Preventive measures, including physical exercise, mental stimulation, avoidance of depression, good nutrition, and abstinence from tobacco use, are useful approaches to postpone or ameliorate the consequences of aging and allow patients to tolerate cardiovascular diseases better when they become manifest.

Incidence and predictors of major hemorrhagic complications from thrombolytic therapy in patients with massive pulmonary embolism

PURPOSE

The risk factors for bleeding in patients receiving recombinant tissue-type plasminogen activator for massive pulmonary embolism are not known.

PATIENTS AND METHODS

The hospital records of 132 consecutive patients who received recombinant tissue-type plasminogen activator for massive pulmonary embolism were retrospectively reviewed. Bleeding was estimated by using the bleeding severity index, a method previously validated in patients receiving anticoagulants. Multivariate stepwise logistic regression was used to identify independent risk factors for bleeding. Four other definitions of bleeding in large pulmonary embolism thrombolytic trials were also used, and the agreement among these criteria was assessed.

RESULTS

According to the bleeding severity index, 33 patients (25%) had one or more major bleeding complications. Hemorrhage at the venous puncture site for angiography was the most frequent complication (15 patients, 11%). Major bleeding at the catheterization site was more common at the femoral site (14 of 63 patients = 22%) than at the brachial site (1 of 63 patients = 2%; P = 0.0004). The use of the five different bleeding definitions resulted in a variation in the major bleeding rate from 3% to 43%. The kappa coefficient varied from 0.07 to 0.84, indicating poor agreement between most of the classifications.

CONCLUSION

The use of the femoral vein for pulmonary angiography was the only variable significantly associated with major bleeding. Most of the differences observed in the pulmonary embolism thrombolytic trials are likely related to the differences in the definition of bleeding rather than to the thrombolytic regimen.