Abstract 12132: Impact of Primary Coronary Angioplasty Delay on Microvascular Obstruction as Assessed by Coronary Flow Velocity Measurements and Left Ventricular Dilatation in ST-Segment Elevation Myocardial Infarction
Background: The impact of total ischemic time on microvascular obstruction as assessed by coronary flow velocity measurements (MVO-CFV) and left ventricular (LV) dilatation has been insufficiently studied. This study investigated the relationship between LV dilatation and the incidence of MVO-CFV worsened by primary coronary angioplasty delay in patients with ST-segment elevation myocardial infarction (STEMI).
Methods: Because of the low incidence of microvascular obstruction (MVO) in the presence of normal blood flow before percutaneous coronary intervention (PCI) as previously reported, 34 patients with pre-procedural TIMI 3 flow were excluded. A total of 193 consecutive patients with first anterior STEMI who underwent angioplasty were subjected to CFV measurement with a Doppler guidewire. The CFV spectrum provided the systolic peak velocity and diastolic deceleration time (DDT). We defined the presence of MVO-CFV as a DDT of ≤600 ms and the appearance of systolic flow reversal. Left ventriculogram obtained 6 months after the infarction was analyzed to measure the LV volume index.
Results: All patients who achieved reperfusion within 120 min after symptom onset were successfully salvaged from MVO-CFV. There was a significant correlation between duration of ischemia and incidence of MVO-CFV (P < 0.01). There were no changes in the incidence of MVO-CFV beyond 240 min after symptom onset. We classified the patients into three categories according to duration of ischemia: ≤120 min, >120 to 240 min, and >240 min. Earlier reperfusion was associated with a significantly lower risk of MVO-CFV (0/18 [0%], 29/73 [40%], and 63/102 [62%], respectively; P < 0.01). Patients with later reperfusion group had a significantly larger LV end-diastolic volume index at 6 months after the infarction (80±13 vs. 95±23 vs. 108±26 ml/m2, respectively; P < 0.01).
Conclusions: Earlier reperfusion (≤120 min after symptom onset) critically determines coronary microvascular integrity, and recanalization delays in time to reperfusion with primary PCI adversely affect LV dilatation in patients with anterior STEMI.
- Intravascular ultrasound/Doppler
- Myocardial infarction, STEMI
- Coronary microcirculation
- Interventional cardiology
- © 2012 by American Heart Association, Inc.