Abstract 12374: Impact of Total Ischemic Time on Microvascular Obstruction and ST Segment Re-elevation at Reperfusion in Patients With Acute Myocardial Infarction
Background: Previous studies have reported that ST re-elevation at reperfusion is a sign of limited myocardial salvage by thrombolysis in patients with acute myocardial infarction (AMI). However, the relationship between ST re-elevation and quantification of the degree of ischemic microvascular damage resulting from angioplasty delay has been insufficiently studied. The purpose of this study was to investigate the relationship between ST re-elevation at reperfusion and quantification of the degree of ischemic microvascular damage worsened by primary coronary angioplasty delay in patients with AMI.
Methods: A total of 193 consecutive patients with first anterior AMI who underwent successful percutaneous coronary intervention (PCI) were subjected to coronary flow velocity measurement with a Doppler guidewire. The coronary flow velocity spectrum provided the following parameters: systolic peak velocity and diastolic deceleration time (DDT). We defined the presence of microvascular obstruction as a DDT of ≤ 600 ms and the presence of systolic flow reversal. Additional ST-segment elevation (>2 mm) immediately after PCI, in the absence of mechanical obstruction, was defined as ST re-elevation. We classified the patients into three categories according to duration of ischemia: ≤120 min (group 1), >120 to 240 min (group 2), and >240 min (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 obstruction: 0/18 (0%) for group 1, 29/73 (40%) for group 2, and 63/102 (62%) for group 3 (P < 0.05). The ischemic time was significantly correlated with the DDT (group 1 vs. group 2 vs. group 3; 777±125 vs. 595±228 vs. 474±250 ms, P < 0.05) and the systolic peak velocity (16±10 vs. -0.5±23 vs. -13±25 cm/s, P < 0.05). Patients with later reperfusion had a significantly higher risk of ST re-elevation: 0/18 (0%) for group 1, 30/73 (41%) for group 2, and 49/102 (48%) for group 3 (P < 0.05).
Conclusions: The findings of this study demonstrate that earlier reperfusion (≤120 min after symptom onset) was significantly associated with a lower risk of ST re-elevation and incidence of microvascular obstruction.
- Intravascular ultrasound/Doppler
- Myocardial infarction, STEMI
- Coronary microcirculation
- Reperfusion injury
- Interventional cardiology
- © 2012 by American Heart Association, Inc.