The risk of stroke in patients with acute myocardial infarction after thrombolytic and antithrombotic treatment. Gruppo Italiano per lo Studio della Sopravvivenza nell'Infarto Miocardico II (GISSI-2), and The International Study Group

Individual risk assessment for intracranial haemorrhage during thrombolytic therapy

Thrombolytic therapy improves outcome in patients with myocardial infarction but is associated with an increased risk of intracranial haemorrhage. For some patients, this risk may outweigh the potential benefits of thrombolytic treatment. Using data from other studies, we developed a model for the assessment of an individual's risk of intracranial haemorrhage during thrombolysis. Data were available from 150 patients with documented intracranial haemorrhage and 294 matched controls. 49 patients with intracranial haemorrhage and 122 controls had been treated with streptokinase, whereas 88 cases and 148 controls had received alteplase. By multivariate analysis, four factors were identified as independent predictors of intracranial haemorrhage; age over 65 years (odds ratio 2.2 [95% Cl 1.4-3.5]), body weight below 70 kg (2.1 [1.3-3.2]), hypertension on hospital admission (2.0 [1.2-3.2]), and administration of alteplase (1.6 [1.0-2.5]). If the overall incidence of intracranial haemorrhage is assumed to be 0.75%, patients without risk factors who receive streptokinase have a 0.26% probability of intracranial haemorrhage. The risk is 0.96%, 1.32%, and 2.17% in patients with one, two, or three risk factors, respectively. We present a model for individual risk assessment that can be used easily in clinical practice.

Is there an age limit for thrombolytic therapy?

Thrombolytic therapy has revolutionized the treatment of acute myocardial infarction. The mortality of infarction increases very steeply with increasing age > 65 years. One-month mortality in such patients is in the range of 20-30%. The proportional benefit of lytic treatment is somewhat less in these older patients, but since mortality is high, the absolute benefit is as large or larger than that in younger patients. The risks of stroke due to thrombolysis are balanced between increased risk of cerebral hemorrhage but decreased risk for ischemic/embolic stroke. This trade-off results, overall, in a slightly increased stroke rate of about 1-2 per 1,000 nonfatal strokes, but with about 20 fewer deaths per 1,000 myocardial infarctions. In addition to these striking mortality benefits, there are also important reductions in infarct size, leading to decreased morbidity from heart failure or arrhythmias.

Aggressive treatment of acute myocardial infarction. Management options for various settings

Multiple lifesaving options are currently available for treatment of acute myocardial infarction as a medical emergency. Serial electrocardiography and continuous ST-segment monitoring, urgent echocardiography, rapid enzyme analysis, and cardiac catheterization may all assist in the accurate and early diagnosis of acute myocardial infarction. Both intravenous thrombolytic therapy and direct infarct percutaneous transluminal coronary angioplasty are of benefit in early treatment. The choice of therapy depends on the individual patient and the hospital capabilities. Adjunctive pharmacologic therapies can be easily administered in the community hospital setting and should be considered for every patient with suspected acute myocardial infarction. The risk of serious morbidity and hospital death in these patients has not been eliminated, and a more aggressive approach to diagnosis and treatment is sorely needed.

Thrombolytic therapy for women with myocardial infarction: is there a gender gap? Thrombolysis and Angioplasty in Myocardial Infarction Study Group

OBJECTIVES

The goal of this study was to investigate whether female gender portends an adverse prognosis independent of the severity of the underlying disease after acute myocardial infarction treated by thrombolysis. A total of 348 women were compared with 1,271 men enrolled in the Thrombolysis and Angioplasty in Myocardial Infarction (TAMI) trials.

BACKGROUND

The reasons for gender differences in the management and prognosis of acute coronary artery syndromes remain poorly defined. The extent to which gender itself explains observed differences in outcome and use of diagnostic procedures remains unclear because confounding factors have not been specified.

METHODS

Patients < 76 years of age presenting within 6 h of onset of ischemic symptoms with electrocardiographic ST segment elevation and without contraindications to thrombolysis, previous infarction in the same distribution or cardiogenic shock were prospectively enrolled in Phases 1 to 3, 5 and 7 of the TAMI trials. All patients received recombinant tissue-type plasminogen activator, urokinase or a combination of both agents. Protocol-mandated cardiac catheterization was performed during the hospital period. Rescue coronary angioplasty was carried out for reperfusion failure at angiography 90 min after initiation of thrombolytic therapy. Coronary artery bypass grafting or coronary angioplasty was performed for clinical indications.

RESULTS

Women were older than men (61.0 +/- 9.7 vs. 55.8 +/- 10.1 years, mean +/- SD) and had a higher incidence of many risk factors for adverse outcome after myocardial infarction. There were no differences in baseline hemodynamic variables or time to thrombolytic treatment. Rates of acute and predischarge infarct-related artery patency and global and regional left ventricular function were similar in the two groups. Rates of in-hospital coronary angioplasty (52.6% and 54.1%) and bypass graft surgery (20.4% and 22.0%) were comparable in women and men, respectively. Women had higher unadjusted rates of mortality (9.2% vs. 5.4%, p = 0.014), reinfarction (6.4% vs. 2.6%, p = 0.005) and hemorrhagic stroke (2.0% vs. 0.55%, p = 0.017) than did men during the hospital period. When adjusted for clinical and angiographic variables, differences in mortality and hemorrhagic stroke did not reach statistical significance, and the risk of reinfarction was only marginally associated with gender.

CONCLUSIONS

In selected patients undergoing thrombolytic therapy and cardiac catheterization for acute myocardial infarction, adjusted mortality rates and utilization of postlysis revascularization are similar in women and men. However, women may be at increased risk for reinfarction.

After correcting for worse baseline characteristics, women treated with thrombolytic therapy for acute myocardial infarction have the same mortality and morbidity as men except for a higher incidence of hemorrhagic stroke. The Investigators of the International Tissue Plasminogen Activator/Streptokinase Mortality Study

BACKGROUND

In the prethrombolytic era, women with myocardial infarction were reported to have a worse outcome than men. This analysis evaluates the association of sex with morbidity and mortality after thrombolytic therapy.

METHODS AND RESULTS

Data were analyzed from 8261 of the 8387 randomized patients with acute myocardial infarction who received thrombolytic therapy in the International Tissue Plasminogen Activator/Streptokinase Mortality Study (baseline data were missing for 126 patients) and were followed for 6 months. Women made up 23% (n = 1944) of the study population. Baseline characteristics were worse in women: they were 6 years older, were more likely to have a history of previous infarction (P < .01), antecedent angina (P < .01), hypertension (P < .0001), or diabetes (P < .0001); were in a higher Killip class on admission (P < .0002); and received thrombolytic therapy 18 minutes later than men (P < .0001). Fewer women were smokers (P < .0001). Women had a higher hospital (12.1% versus 7.2%, P < .0001) and 6-month mortality (16.6% versus 10.4%, P < .0001) and were more likely to develop cardiogenic shock (9.1% versus 6.3%, P < .0001), bleeding (7.2% versus 5.3%, P < .01), and hemorrhagic (1% versus 0.3%, P < .001) or total stroke (2.2% versus 1.1%, P < .0001) during hospitalization. Reinfarction rates and requirement for angioplasty or surgery did not differ. After correction for worse baseline characteristics, women had similar morbidity and mortality apart from a significantly higher incidence of hemorrhagic stroke, which remained significant even after accounting for weight and treatment allocation (odds ratio, 2.90; P < .01).

CONCLUSIONS

After thrombolytic therapy for acute myocardial infarction, women have similar morbidity and mortality to men but suffer from a higher incidence of hemorrhagic stroke.

Intracerebral hematoma related to thrombolysis for myocardial infarction

The incidence of intracerebral hematomas after myocardial infarction increases after thrombolysis. As noted in the case described, clots formed after the administration of thrombolytic agents may remain liquid, and this blood can be drained by a catheter. However, in this case, the patient continued to bleed locally. This problem requires the development of methods to stop such ongoing local bleeding. It may be prevented in the future by improved thrombolytic drugs.

Long-term results of a single protocol for thrombolysis in acute lower-limb ischaemia

In a prospective study, 78 of 157 patients with acute lower-limb ischaemia were considered suitable for thrombolysis. The immediate and 4-year results of 52 patients managed by a single protocol are reported. Of 34 patients alive at 4 years, 23 had limb salvage. Initial treatment produced effective lysis in 38 patients (73 per cent) with significant benefit in 35 (67 per cent); that benefit was sustained for a minimum of 4 years in 30 patients (58 per cent). Seven of the 18 deaths by 4 years occurred within 30 days. Amputation was carried out in six patients within 30 days and in five during the next 4 years. Delayed amputation followed persistent distal occlusion or progression of distal disease. No death or amputation was caused by complication of treatment. In selected patients the risks of thrombolysis can be reduced to an acceptable level by personal supervision and a strict protocol. In survivors, limb salvage is generally sustained for at least 4 years.

Age-related variability in the use of cardiovascular imaging procedures

OBJECTIVE

To determine if older patients undergo fewer cardiovascular imaging procedures (CIPs) than younger patients when admitted to a tertiary care academic medical center for an acute myocardial infarction (MI), after adjusting for disease severity and comorbidities.

DESIGN

Non-current prospective cohort study.

SETTING

Urban tertiary care academic medical center.

PATIENTS

Medical records of 294 patients admitted and diagnosed with an acute MI between January 1990 and April 1991 were reviewed.

MEASUREMENTS

The total number of different CIPs performed during hospitalization was determined. Cardiac catheterizations, echocardiograms, radionuclide ventriculograms, and thallium scans counted as CIPs. Disease severity was assessed by the Acute Physiology Score (APS) of APACHE II, admission Killip's Classification, and peak creatine phosphokinase (CPK) levels. Comorbidities were assessed using a modified Comorbidity Damage Index of Charlson.

RESULTS

The mean (+/- SD) number of different CIPs performed during hospitalization was significantly less for those > or = 75 years old (1.3 +/- 1.0) than for those < 75 years old (1.7 +/- 1.0) (P = 0.01), and CIP number negatively correlated with age (Spearman r = -0.178; P = 0.01). Mean CIP number decreased from 2.0 +/- 1.1 for those < 45 years old to 0.9 +/- 0.6 for those > or = 85 years old (P = 0.02). Other factors positively associated (P < 0.10) with CIP number were: CPK values in the highest quartile of the study population (> 355 U/L); admission to a cardiology, medical, or family practice service; no CIP performed at an outside hospital prior to transfer; admission Killip's Classification of less than IV, and a Q-wave MI. After adjusting for these variables in a multiple regression model, age > or = 75 remained an independent predictor of decreased CIP use (P = 0.003). The modified comorbidity index score and the APS score, a general measure of severity of illness, were not significantly associated with CIP use. When procedures were examined individually, no significant age-related differences were noted in the use of thallium scans, radionuclide ventriculograms, or echocardiograms. Older patients did, however, remain less likely to undergo cardiac catheterizations (P < 0.001).

CONCLUSION

Older patients, regardless of underlying disease severity or comorbidities, undergo fewer invasive cardiovascular evaluations than younger patients when admitted to a tertiary care academic medical center for an acute MI.

Short-term effects of early intravenous treatment with a beta-adrenergic blocking agent or a specific bradycardiac agent in patients with acute myocardial infarction receiving thrombolytic therapy

OBJECTIVES

This study was conducted to explore mechanisms that could explain the possible clinical benefit of early administration of a beta 1-selective adrenoreceptor blocking agent or a bradycardiac drug as adjunct to thrombolysis in acute myocardial infarction.

BACKGROUND

The effects of beta-blockers given concomitantly with thrombolytic therapy in patients with acute myocardial infarction have not been fully examined. The potential role of specific bradycardiac agents lacking negative inotropism as an alternative to beta-blockers in this setting has never been studied in humans.

METHODS

In a double-blind study, we examined the effects of early intravenous and continued oral administration of a beta-blocker (atenolol), a specific bradycardiac agent (alinidine) or placebo on left ventricular function, late coronary artery patency, infarct size, exercise capacity and incidence of arrhythmias.

RESULTS

A total of 292 patients with acute myocardial infarction of < or = 5 h duration and without contraindications to thrombolytic or beta-blocker therapy were studied. Of these, 100 were allocated to treatment with atenolol (5 to 10 mg intravenously followed by 25 to 50 mg orally every 12 h), 98 to alinidine (20 to 40 mg intravenously followed by 20 to 40 mg orally every 8 h) and 94 to placebo. All patients received 100 mg of alteplase over 3 h and full intravenous heparinization. No significant differences in coronary artery patency, global ejection fraction or regional wall motion were observed at 10 to 14 days among the three groups. Likewise, enzymatic and scintigraphic infarct size were also very similar. Neither atenolol nor alinidine was associated with a significant reduction in the incidence of arrhythmias during the 1st 24 h. No significant differences in clinical events were observed, with the exception of a greater incidence of nonfatal pulmonary edema in the atenolol group (6% vs. 1% in the alinidine group and 0% in the placebo group, p = 0.021).

CONCLUSIONS

In the absence of contraindications, the administration of a beta-blocker or a specific bradycardiac agent together with thrombolytic therapy was safe. In this limited number of patients, these agents did not appear to enhance myocardial salvage or preservation of left ventricular function or to reduce the incidence of major arrhythmias in the early phase of infarction.

Myocardial infarction, thrombolytic therapy, and stroke. A community-based study. The MITI Project Group

BACKGROUND

Thrombolytic therapy used in patients with acute myocardial infarction may increase the risk of stroke. Scant information is available from community-based studies.

SUMMARY OF REPORT

Among 5,635 consecutive patients admitted with acute myocardial infarction to hospitals in Seattle and surrounding suburban King County, Washington, 116 (2.1%) experienced strokes during hospitalization. Of these strokes, 82 (71%) were ischemic and 34 (29%) were hemorrhagic, defined by a patient's having had a computed tomographic scan of the head that showed blood. Thrombolytic therapy was given to 1,413 of these patients (25%) and was associated with increased risk of hemorrhagic stroke but reduced risk of ischemic stroke. The relative risk of stroke with thrombolytic therapy was estimate using multiple logistic regression to adjust for potential confounding factors. The adjusted relative risk for hemorrhagic stroke was 3.6 (95% confidence interval [CI], 1.7-8.0); for ischemic stroke, 0.4 (95% CI, 0.2-0.9); and for overall stroke, 1.0 (95% CI, 0.6-1.7). The adjusted risk for death from any cause following stroke was 3.0 (95% CI, 1.4-6.4).

CONCLUSIONS

Although thrombolytic therapy had little effect on the overall occurrence of stroke, thrombolytic therapy increased the risk of stroke death because more patients with hemorrhagic than ischemic strokes died during their hospitalization. The rates of hemorrhagic stroke with thrombolytic therapy reported in the present study are higher than those reported in clinical trials in which treatment is given to select patients under strict protocols.

An overview of the patency and stroke rates following thrombolysis with streptokinase, alteplase, and anistreplase used to treat an acute myocardial infarction

The results of an overview of early (90-240 min) and late (24 hours or more) patency and of stroke rates for each of the three commercially available thrombolytic agents, streptokinase, alteplase, and anistreplase are presented. Studies included in this analysis are all those published between 1985 and March 1992 and focus on the licensed dosage regimens of each agent. The rates of early and late patency for streptokinase were 64.7% and 80.8%; for alteplase, 66.6% and 73.7%; and for anistreplase, 72.1% and 84.5%. The rates of total and hemorrhagic stroke for streptokinase were 0.69% and 0.17%; for alteplase, 1.27% and 0.50%; and for anistreplase 0.91% and 0.38%. These results provided evidence that the rates of early and late patency appeared to be greatest for anistreplase and that the rates of stroke are within "acceptable" ranges for all three thrombolytic agents with streptokinase affording the lowest rate.

Reperfusion revisited

The field of thrombolytic treatment for a variety of clinical conditions has progressed extremely rapidly over the past decade. Unfortunately, answers to questions of the greatest interest to practicing physicians remain ambiguous. They include the following: For which problems should thrombolytic treatment be the treatment of choice? Which patients should receive thrombolytic treatment, and which should not? Which of the available thrombolytic agents is "best" for which problem in which patient? In this situation of clinical ambiguity, our experience with thrombolysis in AMI is instructive. The problems for which thrombolytic treatment are indicated have in common the attribute that they are "time-sensitive"; that is, optimal benefit is achieved with earlier initiation of treatment. We have learned that to minimize delay, emergency physicians must proactively agree with our colleagues in cardiology, family practice, internal medicine, pulmonary medicine, etc., on issues of patient selection, drug selection, and ancillary therapy. It is too late to argue such issues once the patient with a thrombotic or embolic disorder has arrived in the emergency department. By cooperating in advance, we can ensure our patients the maximum benefit from timely administration of this potent therapy while protecting them from avoidable complications and expense from its medically inappropriate use.

Propylthiouracil (PTU)-induced agranulocytosis treated with recombinant human granulocyte colony-stimulating factor (G-CSF)

Two premenopausal female patients with Graves' hyperthyroidism and propylthiouracil (PTU)-induced agranulocytosis are presented. The first patient, age 47, received 300 mg of PTU per day and developed agranulocytosis within 6 weeks of the commencement of therapy. There were no granulocytes in the peripheral smear and a bone marrow biopsy demonstrated an absence of the entire myeloid cell line as well as the presence of many granulomas. The second patient, age 39, received PTU 1600 mg per day for two and half weeks and then 2 days of methimazole, 200 mg per day. She developed complete agranulocytosis on peripheral smear within 3 weeks of the initiation of therapy. Her bone marrow biopsy demonstrated maturation arrest of the granulocytic cell line at the myelocyte stage. In addition to discontinuing their antithyroid drugs, both patients were treated with G-CSF subcutaneously. The first patient received 300 micrograms of G-CSF on days 2 and 4 after discontinuing PTU with the appearance of 4.7 x 10(9)/L granulocytes and granulocyte precursors on day 4. The second patient received 575 micrograms of G-CSF for 2 days and 300 micrograms for 1 additional day beginning on the third day after discontinuing antithyroid drugs. On the second treatment day there were 5.8 x 10(9)/L granulocytes and granulocyte precursors on the peripheral smear. A comparison to previously published cases on antithyroid drug induced agranulocytosis suggests that the use of G-CSF decreased the amount of time required for marrow recovery after the cessation of the offending drug.