Quantitative coronary angiography during intracoronary streptokinase in acute myocardial infarction: How long to continue thrombolytic therapy?

Abstract

An intracoronary infusion of streptokinase is often administered in patients with acute myocardial infarction. To address the question of how long intracoronary streptokinase should be infused, we studied 13 patients with symptoms and electrocardiographic findings suggesting an evolving myocardial infarction. We used subselective catheterization techniques and made quantitative angiographic measurements of the percentage of reduction of coronary artery (CA) diameter before intracoronary streptokinase therapy, immediately after reperfusion was established, and at the completion of streptokinase infusion. Before intracoronary streptokinase and after intracoronary nitroglycerin, nine patients had 100% obstruction of the CA in the "infarct-related vessel." In seven patients reperfusion was established (25 +/- 21 min, mean +/- SD) at which time CA diameter was reduced by 77 +/- 22%. The streptokinase infusion was then continued until repeated films (every 10 to 15 min) suggested no further change at the site of CA obstruction (93 +/- 68 min). The percentage of CA diameter reduction when streptokinase infusion was discontinued was 55 +/- 32%; this value was less (P less than 0.05) than that observed early after reperfusion. These data show that after initial reperfusion was achieved by the use of intracoronary streptokinase, additional streptokinase lessened the reduction of CA diameter. Residual thrombus may be present at the narrowed CA site early after reperfusion, and further "cleanup" can be achieved by prolonging streptokinase infusion.

Incomplete lysis of thrombus in the moderate underlying atherosclerotic lesion during intracoronary infusion of streptokinase for acute myocardial infarction: quantitative angiographic observations.

“…This failure to fully recanalize to the dimensions of the original stenosis has at least four possible explanations: First, the thrombolytic infusion may not have been continued long enough. Feldman et al 24 have shown an improvement in stenosis severity with continued streptokinase infusion to as long as 180 min. Our resistance data suggest that active recanalization continues for at least 60 min after the time of first visualization (see figure 7).…”

“…Harrison et al',5 without making the distinction between the "original" and "recanalized" lumen, observed that lumen area of less than 0.4 mm2 (0.7 mm mean diameter) after infusion of streptokinase predicted eventual reocclusion. Finally, Sheehan et al [22][23][24][25][26][27][28][29][30][31][32][33][34][35][36][37][38][39][40] have determined that improvement of myocardial contractile function does not occur if residual stenosis lumen diameter measured by the above method is less than 0.4 mm.…”