Abstract 4359: Recanalization Within 90 Minutes of Symptom Onset Critically Determines Coronary Microvascular Integrity in Patients With ST-Elevation Myocardial Infarction
Background: AHA/ACC guidelines for the management of patients with ST-elevation myocardial infarction recommends that primary percutaneous coronary intervention (PCI) should be performed as quickly as possible, with a goal of within 90 minutes. However, it has been reported that even if successful earlier reperfusion is achieved in epicardial coronary arteries, microvascular dysfunction causes insufficient reperfusion of the infarcted myocardium, leading to poor outcome. The purpose of this study was to examine the effects of recanalization within 90 minutes on the coronary microvascular integrity in patients with acute myocardial infarction (AMI).
Methods: Two hundred and eleven consecutive patients with first anterior AMI who underwent successful PCI were subjected to coronary flow measurement with a Doppler guidewire. The coronary flow velocity spectrum provided the following parameters: time-averaged peak velocity (cm/s, APV), systolic peak velocity (cm/s, SPV) and diastolic deceleration time (ms, DDT). We defined the presence of microvascular dysfunction as DDT of ≤600 ms and the presence of systolic flow reversal. We classified the patients into three categories according to time from symptom onset to first balloon inflation: <90 minutes (group 1), 90 –180 minutes (group 2), 180 < minutes (group 3).
Results: As for the relationship between the ischemic time and the severity of microvascular injury after PCI, earlier reperfusion was associated with a significantly lower risk of microvascular dysfunction: 0/12 (0%) for group 1, 12/42 (29%) for group 2, and 77/157 (49%) for group 3. The ischemic time was significantly correlated with the diastolic deceleration time (group 1 vs. group 2 vs. group 3; 806±122 vs. 638±213 vs. 542±252 ms, p<0.05) and the peak systolic velocity (22±11 vs. 2±24 vs. −6±25 cm/s, p<0.05).
Conclusions: In patients with AMI, coronary microvascular damage after successful PCI occurs in a time-dependent matter. In particular, all patients who achieved reperfusion within 90 minutes after the symptom onset were successfully salvaged from microvascular dysfunction. Early recanalization within 90 mnutes critically determines coronary microvascular integrity in patients with anterior AMI.