Preservation of myocardial microcirculation during mechanical reperfusion for myocardial ischemia with either abciximab or eptifibatide

Myocardial Blush Grade (MBG) is an angiographic method of assessing myocardial microcirculation and provides independent risk stratification among patients with normal TIMI 3 flow. Although the beneficial effect of abciximab on microvascular perfusion is well established, the efficacy of eptifibatide in the prevention of platelet aggregation and distal microembolization is less proven. After a pharmacologic shift by our institution towards the use of eptifibatide in patients with unstable angina presenting for PCI, we sought to evaluate our experience by retrospectively comparing the effect on myocardial perfusion between abciximab and eptifibatide following PCI in stable angina or acute coronary syndrome. Microcirculatory perfusion was reviewed in 101 consecutive patients (23 stable angina, 61 unstable angina, 17 non-q MI) undergoing PTCA/stenting. This comparison was between the last group of 51 patients who routinely received standard bolus and infusion of abciximab and the first group of 50 patients who began receiving standard bolus and infusion of eptifibatide. Baseline characteristics between the two groups were balanced, except for more patients with previous CABG in the eptifibatide group. Angiograms were evaluated by 2 blinded independent reviewers for MBG as follows: 0, no blush; 1, minimal blush; 2, moderate blush; and 3, normal blush. TIMI 3 flow was seen in 98 patients. MBG scores were not significantly different in the abciximab group (67% MBG 3; 31% MBG 2; 2.0% MBG 0-1) than in the eptifibatide group (58% MBG 3; 36% MBG 2; 6.0% MBG 0- 1); p = 0.34. Patients with prior PTCA/stenting had lower MBG scores (0-2) compared to patients without prior PTCA (58% vs 31% p = 0.03). There were significantly lower MBG scores in all patients with prior PTCA or CABG compared to patients without (55% vs 30%; p = 0.03). MBG scores significantly and inversely correlated with peak troponin I levels (r = -0.18 one-tailed p = 0.04). The similarity in myocardial perfusion between abciximab and eptifibatide suggests that both compounds are equally effective in reducing platelet aggregation and microembolization during mechanical reperfusion. Lower MBG scores in patients with prior PTCA or revascularization may be explained by irreversible microvascular dysfunction resulting from distal microembolization during the previous procedure. Lower MBG scores in patients with higher troponin I levels may reflect more frequent microemboli and microinfarcts during an ischemic event. Larger prospective studies need to be performed to validate these findings.