Even though primary angioplasty is able to obtain TIMI 3 flow in the vast majority of STEMI patients, epicardial recanalization does not guarantee optimal myocardial perfusion, that remain suboptimal in a relatively large proportion of patients. Large interest has been focused in recent years on the role of distal embolization as major determinant of impaired reperfusion. The aim of the current study was to investigate in a large cohort of STEMI undergoing primary angioplasty with Gp IIb-IIIa inhibitors the impact of distal embolization on myocardial perfusion and survival. Our population is represented by patients undergoing primary angioplasty for STEMI included in the EGYPT database. Distal embolization was defined as an abrupt ''cutoff'' in the main vessel or one of the coronary branches of the infarct-related artery, distal to the angioplasty site. Myocardial perfusion was evaluated by angiography or ST-segment resolution, whereas infarct size was estimated by using peak CK and CK-MB. Follow-up data were collected between 30 days and 1 year after primary angioplasty. Data on distal embolization were available in a total of 1182 patients (71% of total population). Distal embolization was observed in 132 patients (11.1%). Patients with distal embolization were older (P < 0.001), with larger prevalence of diabetes (P = 0.01), previous MI (P = 0.048) and advanced Killip class at presentation (P = 0.018), abciximab administration (P < 0.001), with a lower prevalence of smoking (P = 0.04). Patients with distal embolization had more often poor preprocedural recanalization (P = 0.061), less often postprocedural TIMI 3 flow (P < 0.001), postprocedural MBG 2-3 (P < 0.001), complete ST-segment resolution (P = 0.021) and larger infarct size (CK-MB: 328 +/- 356 U/l vs. 259 +/- 226 U/l, P = 0.012). The impact of distal embolization on myocardial perfusion was confirmed after correction for baseline confounding factors as evaluated by MBG 2-3 (adjusted OR [95% CI] = 3.14 [2.06-4.77], P < 0.0001) but not complete ST-segment resolution (adjusted OR [95% CI] = 1.23 [0.84-1.92], P = 0.26). At 208 +/- 160 days follow-up, distal embolization was associated with a significantly higher mortality (9.2% vs. 2.7%, HR [95% CI] = 3.41 [1.73-6.71], P < 0.0001), that was confirmed after correction for baseline confounding factors (adjusted HR [95% CI] = 2.23 [1.1-4.7], P = 0.026). This study showed among STEMI patients treated with Gp IIb-IIIa inhibitors, that distal embolization is independently associated with impaired myocardial perfusion and survival.