Abstract 2811: Time-dependent Impact of Distal Embolization on Myocardial and Microvascular Damage During Primary-Percutaneous Coronary Intervention: a Prospective Magnetic Resonance Study
Background: although angiographic detectable distal embolization (DE) has been recently identified as one of the major drawback of p-PCI in STEMI, its prevention by using mechanical adjunctive devices during primary-percutaneous coronary intervention (p-PCI) has proven no benefit in term of myocardial salvage. Using contrast enhanced-magnetic resonance (ce-MR), we recently showed in humans that the major determinant of the extent of myocardial necrosis is the duration of the ischemia.
Objective: we hypothesized that DE, occurring during p-PCI, may affect myocardial and microvascular damage only in patients treated in the first hours from symptom onset.
Methods: in 240 patients, who underwent p-PCI within 12 hours from symptom onset, we prospectively assessed the impact of DE on infarct size, extent of transmural necrosis and microvascular damage, using ce-MR. Necrosis was considered as transmural when delayed enhancement was extended to > or = 75% of left ventricle segment thickness. The impact of DE was assessed according to time-to-treatment: group 1) < 180 minutes; group 2) ≤ 180 ≥ 360 minutes; group 3) > 360 minutes.
Results: DE occurred in 35 (14.6%) patients. Baseline clinical characteristics were not different between patients. At ce-MR, patients with DE had more often transmural necrosis than patients without DE (80% vs 59%, p=0.018) when time-to-treatment was < 3h, but no impact was proven after this time (p= ns). Total infarct size was not affected by DE regardless of time-to-treatment. Microvascular damage was more frequent in patients with DE (41.2% vs 18.4%, p=0.038), only when treatment was performed < 180 minutes from symptom onset.
Conclusion: distal embolization during p-PCI enhances the transmural extent of myocardial necrosis and the probability of microvascular damage only when it occurs during the first 3 hours from symptom onset, having no impact in patients treated later.