The 1999 guidelines of the ACC/AHA (9) strongly recommend thrombolytic therapy (Class I indication; strong evidence base) for presentations within 12 h of the onset of suggestive clinical features (ischemic chest discomfort or equivalent) with STE (>0.1 mV, 2 or more contiguous ECG leads) or BBB obscuring ST-segment analysis and age <75 yr. Thrombolytic therapy also is generally recommended (Class IIa indication; evidence basis suggestive but less firm) for these same features and age >75 yr (in the absence of contraindications). Therapy is considered possibly effective (Class IIb indication; scientific basis weak, opinion divided), i.e., selected use might be considered, for
ACC/AHA Guidelines for Management of AMI (9)
Prerequisites for considering Choice/time of Adjuvant fibrinolytic therapy fibrinolytic agent therapy
Class I (Available evidence for efficacy and benefit):
1. STE, time to therapy less than 12 h and age <75 yr.
2. BBB with history suggestive of MI.
Class Ila (Weight of evidence favors use/efficacy and benefit): 1. Age >75 yr with STE or BBB, suggestive history, time <12 h.
Class lib (Usefulness/efficacy is less well established):
2. SBP >180 mmHg, or DBP >110 mmHg with high risk MI.
Class III (Evidence for harm):
1. STE, time to therapy >24 h, pain resolved.
2. ST-segment depression.
No specific recommendations:
In patients with large area of infarction, early after symptom onset, and at low risk for ICH, may consider the use of tPA. In smaller infarcts with smaller potential of survival benefit and if a greater risk of ICH exists, SK may be the choice.
Door to needle time less than 30 min.
Aspirin \60-325 mg/d.
ß-blockers unless contraindicated or CHF.
ACE inhibitors for anterior MI, CHF or EF <40% (alternatively; all patients, reassess need for continued therapy at 6 wk).
IV heparin with tPA, rPA, (TNK-tPA) and non-STE-AMI.
SC heparin with SK or APSAC unless at high risk for thromboembolism, when IV heparin is preferred.
CHF, congestive heart failure; DBP, diastolic blood pressure; EF, ejection fraction; ICH, intracerebral hemorrhage; SBP, systolic blood pressure; ACE, angiotensin-converting enzyme.
these ECG findings but time 12-24 h or blood pressure on presentation >180 mmHg systolic and/or >110 mmHg diastolic and a high risk AMI. Thrombolysis is not indicated (Class 3 indication; no evidence of benefit or possibility of harm) for those with STE (or BBB) but time to therapy >24 h and ischemic pain resolved and for those with ST-depression (at any time). These recent ACC/AHA guidelines are summarized in Table 7.
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