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Eligibility for intravenous thrombolysis in suspected acute myocardial infarction
B W Karlson1, J Herlitz, N Edvardsson
1Department of Medicine I, Sahlgrenska Hospital, Göteborg, Sweden.
Insights
This study evaluated eligibility for intravenous thrombolysis in acute myocardial infarction patients. Restrictive criteria (ECG and short delay) identified fewer eligible patients but a higher confirmed infarction rate among those treated.
Area of Science:
- Cardiology
- Emergency Medicine
- Pharmacology
Background:
- Acute myocardial infarction (AMI) is a leading cause of mortality.
- Intravenous thrombolysis is a critical treatment for AMI.
- Optimizing patient selection for thrombolysis is essential for improving outcomes.
Purpose of the Study:
- To assess patient eligibility for intravenous thrombolysis in suspected AMI.
- To evaluate the impact of different electrocardiographic and time-delay criteria on treatment rates.
- To determine the proportion of confirmed infarctions treated and the positive predictive value of treatment.
Main Methods:
- Analysis of 1,715 patients with suspected AMI admitted to an emergency ward.
- Application of varying electrocardiographic criteria (ST elevation) and time windows (6, 12, 24 hours) for thrombolysis eligibility.
- Calculation of treatment eligibility, treated infarction proportions, and positive predictive value.
Main Results:
- Using ST elevation and a 6-hour window, 18% were eligible, treating 37% of confirmed infarctions with 91% positive predictive value.
- Expanding the window to 24 hours increased eligibility to 22% and treated infarctions to 45%.
- Excluding ECG criteria and using only time windows significantly increased eligibility and treated infarctions, while lowering the positive predictive value.
Conclusions:
- Electrocardiographic criteria combined with short time windows identify a select group of AMI patients for thrombolysis with high treatment confirmation.
- Broader time windows or time-only criteria increase treatment reach but may include more non-infarction cases.
- Careful consideration of eligibility criteria is crucial for balancing treatment accessibility and efficacy in AMI management.
Abstract:
Based on the registration of all the 7,157 patients admitted during a 21-month period to the emergency ward of a single hospital in an urban area with chest pain or other symptoms suggestive of acute myocardial infarction, we studied eligibility for intravenous thrombolysis in suspected acute myocardial infarction. We have limited the present analysis to those 1,715 patients with a strong suspicion of myocardial infarction, and for these patients, we have calculated the percentages eligible for thrombolysis when various electrocardiographic and delay time criteria are applied, but we have not considered contraindications to thrombolysis. We have also calculated the proportions of all infarctions in this group that would thereby receive the treatment, and the proportions of patients treated that would develop a confirmed infarction. Using the criteria ST elevation on the initial electrocardiogram and arrival in hospital within 6 hours from onset of symptoms, 18% of patients would have been given early intravenous thrombolysis, 37% of confirmed infarctions would have been treated, and 91% of all treated patients would have developed a confirmed infarction; with a delay time criterion of 12 hours, these percentages would have been 20%, 41%, and 91%, respectively; with a criterion of 24 hours, they would have been 22%, 45%, and 90%, respectively. By not considering the initial electrocardiogram and applying only the criterion of delay time, these percentages would have been 70%, 72%, and 45%, respectively, for a delay time of 6 hours; 83%, 84%, and 45%, respectively, for a delay time of 12 hours; and 91%, 92%, and 44%, respectively, for a delay time of 24 hours.(ABSTRACT TRUNCATED AT 250 WORDS)