No-Reflow Phenomenon Following Percutaneous Coronary Intervention for Acute Myocardial Infarction: Incidence, Outcome, and Effect of Pharmacologic Therapy

Background: No-reflow (NR) phenomenon is a well-known problem, often accompanying percutaneous coronary intervention for acute ST elevation myocardial infarction (STEMI). There are little data on effects of pharmacologic therapy on the resolution, outcome, and long-term natural history of NR. Objective: Retrospectively assess incidence, management, and prognosis of NR in a tertiary referral hospital. Methods: Study included patients with STEMI, treated with percutaneous coronary intervention (PCI). Effect of pharmacologic therapy and long-term outcome were assessed. NR was defined by thrombolysis in myocardial infarction (TIMI) < 3 or myocardial blush grade (MBG) < 3. Results: Of 347 identified subjects, NR occurred in 110 (32%) by TIMI and 198 (57%) by MBG. Higher incidence was identified in men versus women (34% vs. 25% by TIMI, P = 0.08; and 60% vs. 48% by MBG, P = 0.04). Pharmacologic therapy was equally effective in restoring normal flow, increasing TIMI score from 1.62 +/- 0.07 to 2.78 +/- 0.06 (P < 0.0001) and MBG score from 0.43 +/- 0.08 to 2.09 +/- 0.11 (P < 0.0001). Twenty-three percent who did not receive pharmacologic therapy developed clinical composite of congestive heart failure, cardiogenic shock, and/or death; only 9% of patients who received pharmacologic therapy developed this composite. Patients with severe NR despite treatment had poorer prognosis. Sixty-five percent of patients who survived and had repeat angiogram about 1.5 years later had spontaneous improvement in coronary flow by MBG. Conclusion: NR is common in STEMI. Treatment with nicardipine, nitroprusside, and verapamil are equally effective in improving flow. If not treated, prognosis is poor. (J Interven Cardiol 2010;23:429-436).