Development and Validation of a Distal Embolization Risk Score During Primary Angioplasty in ST-Elevation Myocardial Infarction

This study aims to develop and validate a new angiographic risk score to predict the risk of distal embolization (DE) during primary percutaneous coronary intervention (p-PCI) for ST-elevation myocardial infarction. Study included data from 1,200 patients who underwent p-PCI. The cohort was randomly split into a derivation cohort (n = 814) and a validation cohort (n = 386). Logistic regression was used to examine the relation between risk factors and the occurrence of DE. To each covariate in the model was assigned an integer score based on the regression coefficients. Variables included in the risk score, according to multivariable analysis, were occlusion pattern of infarct-related artery, Thrombolysis In Myocardial Infarction Thrombus Score 2 to 4, reference vessel diameter ≥3.5 mm, and lesion length >20 mm. To each variable was assigned a 0- to +2-point score according to the strength of the statistical association. Rates of DE in low-, intermediate-, and high-risk groups were 5.6%, 15.8%, and 40% in the derivation cohort (p for trend <0.0001; C-statistic 0.70) and 7.5%, 12.1%, and 37.9% in the validation cohort (p for trend <0.0001; C-statistic 0.62), respectively. In conclusion, the individual risk of DE in patients who underwent p-PCI can be predicted using a simple 4-variables model based on angiographic features.