No - Reflow

A. DEFINITION. The no-reflow phenomenon was originally observed in experimental models of acute myocardial infarction (MI) and was described as a failure to restore normal myocardial blood flow despite removal of the coronary obstruction. Since that time, no-reflow has been shown to complicate thrombolytic therapy and percutaneous revascularization with PTCA and other devices. Defined angiographically, no-reflow manifests as an acute reduction in coronary flow (TIMI grade 0-1) in the absence of dissection, thrombus, spasm, or high-grade residual stenosis at the original target lesion. Lesser degrees of flow impairment (TIMI grade 2) are generally referred to as “slow-flow.” However, studies of acute MI patients have reported that scintigraphic evidence for no-reflow may occur in the absence of angiographic slow-flow, suggesting that microvascular injury may be angiographically inapparent in some patients. Using the Doppler Flowire, flow velocity patterns of no-reflow in patients with acute MI include systolic retrograde flow, diminished systolic antegrade flow, and rapid deceleration of diastolic flow.