November 27, 2001Circulation109 citationsOpen Access
View Full PaperTime to Treatment Influences the Impact of ST-Segment Resolution on One-Year Prognosis
Key Result
ST-segment resolution at 24 to 36 hours after fibrinolysis was inversely correlated with 1-year mortality (r=-0.963, P<0.001), and treatment <2 hours further reduced mortality across all categories.
Study Design
Type
Cohort (n=13,100)
Structured PICO
Does time to treatment influence ST-segment resolution at 24 to 36 hours and 1-year mortality in patients with acute myocardial infarction receiving fibrinolysis?
P
Population
13,100 patients with acute myocardial infarction treated with fibrinolysis, evaluated for ST-segment resolution at 24 to 36 hours and followed for 1 year.
E
Exposure
Early treatment (<2 hours after symptom onset) and complete ST-segment resolution (≥70%) at 24 to 36 hours
C
Comparator
Later treatment (2-4 hours or 4-6 hours) and partial (30-70%) or no (<30%) ST-segment resolution
O
Outcome
1-year mortalityhard clinical
Time to treatment with fibrinolysis in acute myocardial infarction strongly influences ST-segment resolution at 24-36 hours, which is inversely correlated with 1-year mortality, highlighting the critical importance of minimizing treatment delays.
Main Result
Effect estimate: r=-0.963
p-value: p=<0.001
Abstract
BACKGROUND: Early ST resolution after reperfusion is a prognostic indicator in acute myocardial infarction. Little information exists regarding the prognostic utility of ST resolution beyond 4 hours after fibrinolysis. Furthermore, the relation between time to treatment, ST resolution at 24 to 36 hours, and 1-year outcome has not been well studied. Accordingly, we undertook a prospective ECG substudy in the Assessment of the Safety and Efficacy of a New Thrombolytic (ASSENT-2) trial to examine this. METHODS AND RESULTS: Patients (n=13 100) were stratified into 3 ST-resolution categories, based on baseline and 24- to 36-hour ECGs: complete resolution (>/=70%) in 6698 (51.1%) patients, partial resolution (30% to 70%) in 4610 (35.2%) patients, and no resolution (4 hours (3.8% versus 5.2% and 6.6%, P=0.002 in complete ST resolution; 5.7% versus 8.4% and 9.9%, P=0.001 in partial ST resolution; 7.1% versus 8.7% and 13%, P=0.006 in no resolution). The extent of ST resolution was closely and inversely correlated with 1-year mortality rates (r=-0.963, P<0.001). CONCLUSIONS: ST resolution at 24 to 36 hours after fibrinolysis is influenced by time to treatment and inversely related to 1-year mortality rates. Time to treatment further differentiates between high- and low-risk patients and further highlights the importance of reducing time delay to initiation of fibrinolysis in acute myocardial infarction.