Impact of normalized myocardial perfusion after successful angioplasty in acute myocardial infarction

OBJECTIVES: We sought to evaluate and validate the ability of the angiographic myocardial blush grade to risk stratify patients after successful angioplasty in acute myocardial infarction (AMI). BACKGROUND: Although epicardial Thrombolysis In Myocardial Infarction (TIMI)-3 flow is restored in >90% of patients undergoing primary percutaneous coronary intervention (PCI), normal myocardial perfusion may be present less frequently and may detrimentally impact survival. METHODS: A cohort of 173 consecutive patients undergoing intervention within 24 h of AMI onset were studied. High-risk features of this population included failed thrombolysis in 39%, cardiogenic shock in 17% and saphenous vein graft culprit in 11% of patients. RESULTS: Despite the restoration of TIMI-3 flow in 163 (94.2%) patients, myocardial perfusion, as evidenced by normal contrast opacification of the myocardial bed subtended by the infarct artery (myocardial blush), was normal in only 29.4% of patients with TIMI-3 flow following PCI, and in no patient with TIMI 0 to 2 flow. In patients in whom TIMI-3 flow was restored, survival was strongly dependent on the myocardial perfusion grade; one-year cumulative mortality was 6.8% with normal myocardial blush, 13.2% with reduced myocardial blush and 18.3% in patients with absent myocardial blush (p = 0.004). CONCLUSIONS: Abnormal myocardial perfusion is present in most patients following primary or rescue PCI in AMI, despite restoration of brisk epicardial coronary flow. In high risk patients achieving TIMI-3 flow after intervention, the myocardial blush score may be used to stratify prognosis into excellent, intermediate and poor survival. Further study is warranted to examine whether adjunctive mechanical or pharmacologic strategies can further improve myocardial perfusion and survival of patients with acute myocardial infarction undergoing intervention.