A score system to predict no-reflow in primary percutaneous coronary intervention: The PIANO Score

Background: Angiographic no-reflow is associated with poor outcomes in patients with ST-segment elevation myocardial infarction (STEMI). We sought to develop and validate a score system to predict angiographic no-reflow in primary percutaneous coronary intervention (PCI).

Methods: ST-segment elevation myocardial infarction patients undergoing primary PCI were consecutively enrolled and were randomly divided into the training and validation set. Angiographic no-reflow was defined as thrombolysis in myocardial infarction (TIMI) flow grade 0 to 2 after PCI. In the training set, independent predictors were identified by logistic regression analysis, and a score system (PredIction of Angiographic NO-reflow, the PIANO score) was constructed based on the β-coefficient of each variable. The established model was evaluated for discrimination and calibration.

Results: Angiographic no-reflow occurred in 362 (17.8%) of 2036 patients. Age ≥70 years, absence of pre-infarction angina, total ischaemic time ≥4 h, left anterior descending as culprit artery, pre-PCI TIMI flow grade ≤1 and pre-PCI TIMI thrombus score ≥4 were independent predictors of angiographic no-reflow. The PIANO score ranged from 0 to 14 points, yielding a concordance index of 0.857 (95% confidence interval: 0.833 to 0.880), with good calibration. In the high-risk (≥8 points) group, the probability of angiographic no-reflow phenomenon was 38.7%, while it was only 4.8% in the low-risk (<8 points) group. The score system performed well in the validation set.

Conclusions: We establish and validate a score system based on six clinical variables to predict angiographic no-reflow in STEMI patients undergoing primary PCI, which may help choose the optimal individual treatment strategy.