STEMI

After a STEMI, pathologic Q waves are seen frequently on the ECG and usually indicate transmural MI. Non-Q-wave MI, which is seen predominantly in NSTE MI, is limited to the subendocardial myocardium. 

For patients with STEMI treated medically without revascularization, clopidogrel can be given for 14 to 28 days. If a stent has been implanted, clopidogrel can be continued for up to 12 months in patients at low risk for bleeding. 

Obstacles remained as PTCA was not universally available and often associated with considerable time delay, especially in off peak hours. In the National Registry of Myocardial Infarction-2 (NRMI-2 >27,000 patients), total ischemia time (symptom onset to balloon inflation) was 3.9 h with onset to hospital arrival 1.6 h [45]. Unadjusted in-hospital mortality was higher in patients treated later. Door to balloon time > 2 h was related to in-hospital death (41-62% adjusted odds increase) and centers who treat >3 STEMIs/month had improved in-hospital mortality compared to less experienced facilities (Figs. 5.4 and 5.5). Lastly, similar to trials of unstable angina, PTCA was plagued by high restenosis rates... 

Stent therapy in STEMI remained intriguing because it allows for establishment of vessel patency and the ability to protect the culprit lesion. Several trials evaluated PCI versus PTCA, all showing a marked benefit in the combined endpoints of mortality and the requirement of revascularization with stenting [47-49]. The STENT PAMI trial helped shape the future of STEMI treatment. Overall mortality was not significantly different between the two groups however, the combined end point of mortality, reinfarction, stroke, or revascularization was positive at 6 months owing to a marked increase in the requirement for revascularization in the PTCA... 

Table 5.3 ACC/AHA 2004 executive summary guidelines for emergent PCI in STEMI...

If immediately available, primary PCI should be performed in patients with STEMI (including true posterior MI) or MI with new or presumably new LBBB who can undergo PCI of the infarct artery within 12 h of symptom onset, if performed in a timely fashion (balloon inflation within 90 min of presentation) by persons skilled in the procedure (individuals who perform more than 75 PCI procedures per year). The procedure should be supported by experienced personnel in an appropriate laboratory environment (a laboratory that performs more than 200 PCI procedures per year, of which at least 36 are primary PCI for STEMI, and has cardiac surgery capability). (Level of Evidence A)... 

De Luca G, Suryapranata H, Chiariello M. Tenecteplase followed by immediate angioplasty is more effective than tenecteplase alone for people with STEMI. Commentary. Evid Based Cardiovasc Med 2005 9(4) 284-7. 

ST-Elevation Myocardial Infarction (STEMI) is a life-threatening event, thus prehospital treatment is expected to be available by establishing a sophisticated system for this purpose. In this condition a fibrinolysis protocol is advised. 

As was said before, fibrinolytic therapy is recommended in many cases. It is recommended for patients with the onset of the STEMI within 12 hours, for patient with significant EGG changes having ST... 

CPMP (2003) Points to Consider on the Clinical Development of Fibrinolytic Medicinal Products in the Treatment of Patients with ST Segment Evaluation Acute Myocardial Infarction (STEMI) ... 

Abbreviations D, death MI, myocardial infarction NNH, numbers needed to harm NNT, numbers needed to treat PCI, percutaneous coronary inteivention STEMI, ST-elevation myocardial infraction UR, urgent reintervention. 

Whether the timing of GPIIb/llla inhibitor therapy makes any difference on efficacy and safety has been explored retrospectively in six randomized STEMI trials (three with abciximab and three with tirofiban) (69). In a pooled analysis of these trials, upstream (prior to transfer to the catheterization laboratory) administration of GPIIb/llla inhibitor appeared to improve coronary patency and resulted in favorable trends for clinical outcomes compared to downstream (in cath lab) administration. However, the timing of administration was neither randomized nor prespecified. Thus, the suggestion that these drugs may be most beneficial with early (preferably prehospital) treatment of patients in the first hours of acute STEMI awaits confirmation in prospective randomized investigations. 

Abbreviations PCI, percutaneous coronary intervention STEMI, ST-elevation myocardial infraction. 

Antman EM, Anbe DT, Armstrong PW, et al. ACC/AHA 2004 Guidelines for the Management of Patients With ST-Elevation Myocardial Infarction. A Report of the American College of Cardiology/American Heart Association Task Force on Practice Guidelines. Available atwww.acc.org/clinical/guidelines/stemi/ index.pdf. Accessed July 7, 2006. 

COMMIT or CCS-2 (3 I), conducted in China and without a loading dose of clopidogrel, tried to determine whether adding clopidogrel to acetylsalicylic acid (ASA) can produce a further reduction in mortality and the risk of vascular events in hospital for patients admitted with ST-elevation Ml (STEMI). 

Clopidogrel will therefore be part of acute treatment for STEMI and should be administered at the first medical contact. 

The third trial was a subgroup analysis of the CLARITY (29) trial performed in acute Ml. It was demonstrated that in STEM I patients, treated with fibrinolytic and who underwent PCI during the hospitalization period (n = 1863 patients), the dual antiplatelet treatment was able to reduce major vascular events (death, Ml, and stroke) from 12% to 7.5% (RRR = 0.59 95% Cl 0.43-0.81 P = 0.001). Thus, the treatment with clopidogrel + aspirin of 43 STEMI patients followed by PCI prevents one major vascular event. 

ACS can be classified into UA, myocardial infarction (Ml) without ST-segment elevation [non-ST-elevation Ml (NSTEMI)], or STEMI. The presence of cardiac troponin in ACS indicates worse prognosis than the absence of troponin (9). 

This grouping of clinical syndromes are compatible with myocardial ischemia, and a prompt visit to the emergency department is indicated. Electrocardiograms in the emergency department would differentiate a NSTEMI from a STEMI, the latter suggesting a greater degree of myocardial ischemia. 

Antman developed a thrombosis in myocardial infarction (TIMI) risk score based on a database of 15,078 patients with STEMI or new onset of complete left bundle branch block (8), The score was validated in the TIMI 9 data set. Ten characteristics of these patients accounted for 97% of the predictive capacity of their multivariate model. These are included in the risk score (Table I). Points were given for difference parameters as listed in Table I. The risk score had a strong association with 30-day mortality. There was a greater >40-fold increase in mortality from TIMI risk score 0 to >8 at 30 days (Table I) (8), The TIMI risk score is easy to apply and can be done at the bedside. 

Clopidogrel STEMI (10), NSTEMI (11) Elective PCI (l 2) 300 mg loading dose (10-12) unless PCI to be performed within eight hours in which case 600 mg recommended As effective as ticlodipine in preventing stent thrombosis (9) Reduced incidence of adverse hematologic reactions compared to ticlodipine (9)... 

Abciximab STEMI (27), unstable angina (28),elective PCI (29) 0.25mg/kg followed by 0.125 xg/kg/min infusion Benefit in low/intermediate risk patients following clopidogrel pretreatment debated (39,40) Significant benefit (27-29) especially with respect to mortality (27) and reinfarction (27,28) Increased risk of major bleeding and thrombocytopenia compared to other Gp Ilb/IIIa inhibitors (33)... 

Epitifibatide ACS (not including STEMI) (60), nonurgent PCI (34) Two 180 pg/kg boluses 10 min apart and 2pg/kg/min infusion (34) Studies comparing efficacy to other members of this class awaited... 

Ilb/IIIa inhibitors agents are epitifabatide/tirofiban. Abciximab is the preferred agent in the cases of STEMI... 

Abbreviations ACS, acute coronary syndrome ACT, activated clotting time BP, blood pressure CTO, chronic total occlusion i.v., intravenous MI, myocardial infarction NSTEMI, non-ST-segment elevation myocardial infarction PCI, percutaneous coronary intervention RCA, right coronaiy artery STEMI, ST-segment elevation myocardial ... 

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