Half-dose thrombolysis to begin with, when immediate coronary angioplasty in acute myocardial infarction is not possible

Abstract

Background: Low-dose lytic drugs are sometimes administered to patients with ST-elevation acute myocardial infarction (AMI) as a bridge to coronary angioplasty (facilitated PTCA). Reports are scarce. The characteristics and outcomes of a recent series of consecutive patients treated in our Center are presented.

Methods: In August 2000 facilitated PTCA with half-dose reteplase was started in our Center in all cases when the cath lab was not immediately (< 30 min) available, or the patient had to be transferred to us. Since August 2000, 153 patients were admitted to our cath lab to undergo facilitated (n = 80) or primary (n = 73) PTCA. The data of all patients were prospectively collected, and were analyzed on an "intention-to-treat" basis.

Results: No significant differences were found between facilitated and primary PTCA patients with regard to: gender, diabetes, hypertension, previous PTCA/bypass surgery, heart rate at admission, systolic blood pressure, anterior AMI, number of leads with ST-segment elevation, total ST-segment deviation, collateral flow to the infarct-related artery, and three-vessel disease. In our series, facilitated vs primary PTCA patients had a better risk profile: they were younger (61 +/- 13 vs 66 +/- 11 years, p = 0.016), less frequently had a previous AMI (7 vs 24%, p = 0.01), had a shorter time from pain onset to first emergency room admission (122 +/- 104 vs 168 +/- 162 min, p = 0.045), and a trend to a shorter total time to the cath lab (209 +/- 121 vs 255 +/- 183 min, p = 0.073) despite a similar emergency room-to-cath lab component (89 +/- 50 vs 98 +/- 92 min, median 74 vs 65 min, p = NS). Moreover, they presented with a lower Killip class on admission (1.1 +/- 0.4 vs 1.5 +/- 0.98, p = 0.01), with more patients in Killip class 1 (95 vs 74%, p = 0.001). One vs 8% of patients were in shock. Facilitated vs primary PTCA patients had an initial TIMI 2-3 flow in 42 vs 25% of cases (p = 0.031), a final TIMI 3 flow in 82 vs 71% (p = NS), > or = 50% ST-segment resolution in 73 vs 58% (p = NS), and both of the latter in 62 vs 45% (p = 0.099); distal coronary embolization occurred in 9 vs 14% of cases (p = NS); intra-aortic balloon counterpulsation was used in 5 vs 12% and glycoprotein IIb/IIIa inhibitors in 10% of the whole population. The overall in-hospital mortality was 3.7 vs 9.6% (p = NS), and 2.5 vs 4.5% (p = NS) when patients in shock at admission were not considered. Reinfarction occurred in 2 patients submitted to facilitated PTCA (who had had no immediate PTCA, due to full reperfusion) and in none of the patients submitted to primary PTCA; no patient presented with stroke or major bleeding.

Conclusions: Pre-treatment with thrombolysis often provides a patent vessel before PTCA, appears to be safe, and may improve reperfusion after PTCA. In this setting, the additional use of glycoprotein IIb/IIIa inhibitors before PTCA only in non-reperfused patients may be significantly risk- and cost-effective.