Correlates of the "No-Reflow" or "Slow-Flow" Phenomenon in Patients Undergoing Primary Percutaneous Coronary Intervention

Background: Despite recent advances in interventional equipment and techniques, the angiographic no-reflow phenomenon occurs in a considerable number of patients undergoing primary percutaneous coronary intervention (PCI). We investigated the clinical, angiographic, preprocedural, and procedural characteristics associated with the no-reflow phenomenon among patients undergoing primary PCI. Methods: Between March 2008 and April 2013, 530 patients (78.5% male, mean age=58.11±12.39 y) with ST-segment-elevation myocardial-infarction who underwent primary PCI were categorized in 2 groups according to their postprocedural thrombolysis-in-myocardial infarction (TIMI) flow grades: those with a maximum score of 2 (the no-reflow or slow-flow group) and the ones with a score of 3 (the reflow group). A multivariable logistic regression model was used to find the multiple correlates of the no-reflow phenomenon after PCI. Results: There were 166 (31.3%) patients in the no-reflow group and 364 (68.7%) in the reflow group. The no-reflow patients were older and had significantly longer target lesion lengths, higher SYNergy between percutaneous coronary intervention with TAXus and cardiac surgery (SYNTAX) scores, higher infarct-related artery SYNTAX scores, more thrombus burden, and a higher frequency of initial TIMI flow grades of 2 or lower. Our multivariable logistic regression analysis demonstrated that older age, higher numbers of Q waves, not using statin, longer target lesion lengths, higher thrombus grades, and higher infarct-related artery SYNTAX scores remained the independent correlates of increased no-reflow rates after primary PCI (area under the ROC curve=0.784, 95% CI: 0.742-0.826; P<0.001). Conclusion: Clinical, angiographic, and procedural features of patients undergoing primary PCI may be correlated with the occurrence of the no-reflow phenomenon. The thrombus grade and the infarct-related artery SYNTAX score could be among these factors.