Pre-angiography total ST-segment resolution is not a reliable predictor of an open infarct-related artery

Background: While the cutoffs of predictive value for ST-segment elevations resolution (STSR) following thrombolysis and/or primary PCI were well documented, the impact of pre-angiography STSR has not been established yet.

Objectives: The aim of this study is to assess prognostic utility of pre-angiography STSR to predict pre-procedural TIMI flow in the infarct-related artery (IRA) and infarct size in STEMI patients undergoing primary PCI.

Methods: A prospective study was performed, including 310 patients, admitted within 12h of symptom onset and who underwent primary PCI. ST-segment elevations were measured in: (1) qualifying ECG, (2) ECG before angiography, and (3) ECG post PCI. STSR was defined as: total (≥70%), partial (between 70% and 30%) and none (<30%). Relationships between pre-angiography STSR, initial TIMI flow and troponin T level (TnT) were analyzed.

Results: Pre-angiography STSR correlated with initial TIMI flow in the IRA (rS=0.619; p<0.001). Pre-angiography total STSR was observed in 23.2% patients. It was noted in 79.2% of patients with pre-procedural TIMI flow ≥2 and in 20.8% with TIMI flow ≤1 (p<0.001). Although the sensitivity of pre-angiography total STSR to detect pre-procedural TIMI flow ≥2 was 93%, its specificity was only 56% and the likelihood ratio was 2.1. Pre-angiography total STSR was associated with lower peak TnT level (2.2±2.5ng/ml vs. 6.4±5.0ng/ml, p<0.0001) when compared to the remaining patients.

Conclusions: 1. Pre-angiography STSR correlates with preprocedural TIMI flow. 2. The sensitivity of pre-angiography total STSR in detection of pre-procedural TIMI flow ≥2 is high, but low specificity of only 56% makes it an unreliable predictor of an open IRA.