Background

Although microvascular flow abnormalities have been observed following epicardial recanalization in acute ST-segment elevation myocardial infarction (STEMI), the prevalence and severity of these abnormalities in the current era of rapid percutaneous coronary intervention (PCI) has not been evaluated. The objective of this study was to assess microvascular perfusion (MVP) following successful primary PCI in patients with STEMI and how it affects clinical outcome.

Methods

In this single-center, retrospective study, 170 patients who successfully underwent emergent PCI for STEMI were assessed using real-time myocardial contrast echocardiography using a continuous infusion of intravenous commercial microbubbles (3% Definity). Three patterns of myocardial contrast replenishment were observed following intermittent high–mechanical index impulses: infarct zone replenishment within 4 sec (normal MVP), delays in contrast replenishment but normal plateau intensity (delayed MVP [dMVP]), and both delays in replenishment and reduced plateau intensity (microvascular obstruction [MVO]). Changes in left ventricular ejection fraction at 6 months and clinical event rate at 12 months (death, recurrent infarction, need for defibrillator placement, or heart failure admission) were compared.

Results

Normal MVP was seen in 62 patients (36%), dMVP in 49 (29%), and MVO in 59 (35%). Left anterior descending coronary artery infarct location was the only parameter independently associated with dMVP or MVO, independent of age, cardiac risk factors, door-to-dilation time, pre-PCI Thrombolysis In Myocardial Infarction flow grade, and thrombus burden. A dMVP pattern had a similar reduction in left ventricular ejection fraction as MVO at hospital discharge but had recovery of left ventricular ejection fraction at 6 months and a greater than fourfold lower event rate than the MVO group (P < .001).

Conclusions

MVO and dMVP are frequently seen following contemporary successful PCI for STEMI, especially following left anterior descending coronary artery infarction. Despite a similar area at risk, a dMVP pattern has better functional recovery and clinical outcome than MVO.

中文翻译：

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成功的当代经皮冠状动脉介入治疗急性ST段抬高型心肌梗死后微血管血流异常的发生率和预测价值

背景

尽管在急性ST段抬高型心肌梗死（STEMI）的心外膜再通后已观察到微血管血流异常，但在当前快速经皮冠状动脉介入治疗（PCI）时代，这些异常的发生率和严重性尚未得到评估。这项研究的目的是评估STEMI患者成功进行原发性PCI后的微血管灌注（MVP）及其对临床结局的影响。

方法

在这项单中心，回顾性研究中，使用实时心肌造影超声心动图评估了170例成功接受STEMI急诊PCI治疗的患者，并连续输注了商用微泡（3％Definity）。间歇性的高机械指数脉冲后，观察到三种心肌造影剂补充模式：4秒内梗塞区补充（MVP正常），造影剂补充延迟但高原强度正常（MVP延迟[dMVP]）以及补充和减少延迟高原强度（微血管阻塞[MVO]）。比较了6个月时左心室射血分数的变化和12个月时的临床事件发生率的变化（死亡，复发性梗死，除颤器放置的需要或心力衰竭的入院）。

结果

62例患者（36％）的MVP正常，49例（29％）的dMVP，59例（35％）的MVO。左冠状动脉前降支梗死位置是唯一与dMVP或MVO独立相关的参数，与年龄，心脏危险因素，门到扩张时间，PCI溶栓前的心肌梗死血流分级和血栓负荷无关。dMVP模式在出院时左心室射血分数的降低与MVO相似，但在6个月时左心室射血分数的恢复，事件发生率比MVO组低四倍（P  <.001）。

结论

MVO和dMVP通常在现代成功的STEMI PCI手术后出现，尤其是在左前降支冠状动脉梗塞后。尽管存在相似的风险区域，但dMVP模式比MVO具有更好的功能恢复和临床结局。