The aim was to investigate the effect of abciximab on microvascular perfusion in different subgroups of patients undergoing direct PCI for acute STEMI. We enrolled 145 consecutive patients with TIMI grade 3 flow after direct PCI for acute STEMI. The GPIIb/IIIa inhibitor abciximab was administered in 57 patients (39.3%). Myocardial perfusion was the primary outcome measure and was assessed by analysis of cardiac troponin T wash-out. Treatment effects on myocardial perfusion and clinical outcome were tested for predefined subgroups including patients with an admission cTnT > or = 0.1 microg/L, diabetes mellitus, male gender, age > 70 years, and time from symptom onset to reperfusion > 6 hours. A significant improvement of cTnT wash-out was seen in patients with an admission cTnT > or = 0.1 microg/L, in males and in older patients. Improved tissue level reperfusion did not translate into a significant reduction of cardiac mortality or the incidence of the combined endpoint consisting of cardiac death, nonfatal reinfarction and need for target vessel revascularisation during 30 day- and long-term follow-up (mean 274 days). In conclusion, adjunctive administration of abciximab improves myocardial perfusion in patients with normal epicardial flow after direct PCI, particularly in patients with an cTnT > or = 0.1 microg/L on admission, age over 70 years and male gender.