Very early risk stratification after thrombolytic therapy with a bedside myoglobin assay and the 12-lead electrocardiogram.
BACKGROUND
Available clinical criteria to estimate prognosis in patients with evolving ST-segment elevation myocardial infarction do not consider the impact of reperfusion therapy and do not incorporate measurement of baseline levels of cardiac serum markers. We evaluated the combination of a baseline myoglobin assay and early (60- to 90-minute) ST resolution for risk stratification after ST-segment elevation myocardial infarction.


METHODS
In a prospective substudy of the Intravenous nPA for Treatment of Infarcting Myocardium Early-II (InTIME-II) trial carried out in 2079 patients, a rapid qualitative assay for myoglobin was performed immediately before thrombolysis. Serial 12-lead electrocardiograms were performed at baseline and 60 to 90 minutes after thrombolysis. ST resolution was categorized as complete (>/=70%), partial (30% to <70%), or none (<30%).


RESULTS
Mortality rate at 30 days was 3.3% in the 905 patients with a negative baseline myoglobin assay versus 8.9% in the 527 patients with a positive assay (P <.0001). Mortality rate was lowest (2.4%) among the 614 patients with complete ST resolution, intermediate (4.9%) among the 512 patients with partial ST resolution, and highest (8.1%) among the 540 patients with no ST resolution (P <.0001 for trend). In a logistic regression model incorporating other baseline predictors of 30-day mortality rate, both a positive myoglobin assay (relative risk 1.98, 95% confidence interval 1.00-3.90) and ST resolution <70% (relative risk 2.86, 95% confidence interval 1.22-6.69) were independently associated with increased mortality rate. At 30 days, mortality rate was 0.4% among patients with a negative myoglobin assay and complete ST resolution, 4.8% among patients with either a positive myoglobin assay or ST resolution <70%, and 9.6% among those with both a positive myoglobin ratio and ST resolution <70% (P <.001 for trend).


CONCLUSIONS
Within 90 minutes after administering thrombolytic therapy for acute myocardial infarction, clinicians can determine the risk for death at the patient's bedside with a hand-held myoglobin assay and 2 serial 12-lead electrocardiograms. A strategy using these 2 simple, rapid, and inexpensive tests may facilitate triage after thrombolytic therapy.
De Lemos
J A
JA
Division of Cardiovascular Medicine, Brigham and Women's Hospital, Boston, MA 02115, USA. jdelemos@rics.bwh.harvard.edu
Antman
E M
EM
Giugliano
R P
RP
Morrow
D A
DA
McCabe
C H
CH
Charlesworth
A
A
Schröder
R
R
Braunwald
E
E
D000328:Adult; D000368:Aged; D015415:Biomarkers / Q000032:analysis; D004562:Electrocardiography; D005260:Female; D005343:Fibrinolytic Agents / Q000627:therapeutic use*; D006801:Humans; D008297:Male; D008875:Middle Aged; D009203:Myocardial Infarction / Q000145:classification / Q000175:diagnosis* / Q000188:drug therapy; D009211:Myoglobin / Q000032:analysis*; D019095:Point-of-Care Systems; D011446:Prospective Studies; D018570:Risk Assessment; D012680:Sensitivity and Specificity; D013997:Time Factors; D014218:Triage
D015415:Biomarkers; D005343:Fibrinolytic Agents; D009211:Myoglobin