Abstract 8832: Impact of Time Delay to Treatment on Ischemic Microvascular Damage and In-Hospital Complications in Patients with ST-Segment Elevation Myocardial Infarction
Background: Primary percutaneous coronary intervention (PCI) is more effective than thrombolytic therapy for the treatment of ST-segment elevation myocardial infarction (STEMI) when delivered by an experienced team soon after the onset of symptoms. However, data from experimental studies suggest that the extent of microvascular damage is worsened by longer durations of ischemia. The impact of ischemic time on microvascular damage and in-hospital complications has been insufficiently studied. The purpose of this study was to examine the effects of recanalization within 120 minutes on the coronary microvascular integrity and in-hospital event rate.
Methods: Two hundred and eleven consecutive patients with first anterior STEMI who underwent successful PCI were subjected to coronary flow measurement with a Doppler guidewire. The coronary flow velocity spectrum provided the following parameters: systolic peak velocity (SPV) and diastolic deceleration time (DDT). We defined the presence of microvascular obstruction as DDT of ≤ 600 ms and the presence of systolic flow reversal. We classified the patients into two categories according to time from symptom onset to first balloon inflation: ≤ 120 minutes (group 1), 120 < minutes (group 2). The in-hospital event rate was compared among the 2 groups.
Results: As for the relationship between the ischemic time and the severity of microvascular damage, earlier reperfusion was associated with a significantly lower risk of microvascular obstruction: 0/12 (0%) for group 1 and 89/199 (45%) for group 2 (p<0.05). The ischemic time was significantly correlated with the DDT (group 1 vs. group 2; 806±122 vs. 563±247 ms, p<0.05) and the SPV (22±11 vs. -8±25 cm/s, p<0.05). The in-hospital event rates for malignant arrhythmia and congestive heart failure were significantly higher in patients with late reperfusion group (0/12 patients, 0% vs. 87/199 patients, 44%; p<0.05; 0/12 patients, 0% vs. 49/199 patients, 25%; p<0.05, respectively).
Conclusions: Early recanalization within 120 minutes critically determines coronary microvascular integrity, and recanalization delays in time to reperfusion with primary PCI adversely affect in-hospital complications in higher risk patients, such as those with anterior STEMI.
- Intravascular ultrasound/Doppler
- Myocardial infarction, STEMI
- Coronary microcirculation
- Interventional cardiology
- © 2011 by American Heart Association, Inc.