Читать книгу Practical Cardiovascular Medicine - Elias B. Hanna - Страница 105

In the GISSI-1 and ISIS-2 trials and a large meta-analysis, fibrinolytics (mainly streptokinase) have shown:^10,17–19

 A striking 6.5% absolute mortality reduction and 50% relative mortality reduction in the first hour after STEMI onset, called the golden hour

 A 4% absolute mortality reduction in the second hour

 A plateau 3% mortality reduction between 3 and 6 hours (relative mortality reduction ~25%)

 Absolute mortality reduction of ~2% between 6 and 12 hours. Beyond that, between 12 and 24 hours, the benefit is marginal and questionable.

This time-dependent benefit is due to the fact that very early reperfusion of the occluded coronary artery may lead to full recovery of the ischemic tissue and thus prevent necrosis. In addition, fibrinolytic therapy in the first 2–3 hours is highly efficacious in lysing a fresh thrombus.

The benefit is more striking in high-risk subgroups, such as anterior STEMI, STEMI with bundle branch block, or high STEMI risk score (tachycardia, hypotension). The elderly subgroup is the only high-risk subgroup that, paradoxically, only derives a marginal benefit from fibrinolysis; this is partly because of the high bleeding risk but also because of the more extensive CAD that makes it less likely for fibrinolysis to re-establish perfusion; a half-dose TNK is recommended in patients ≥75 (ESC class IIa).

The mortality benefit is also more striking with the fibrin-specific fibrinolytics (~1% additional mortality reduction).