Abstract 1745: Impact of Residual Flow on the Reduction in Infarct Transmurality and Preservation of Myocardial Salvage Following Reperfused ST-Segment Elevation Myocardial Infarction
The presence of residual flow from collaterals or antegrade flow in the infarct related artery is associated with a reduction in infarct size. The impact of residual flow on the reduction in the transmural extent of acute ST-segment elevation myocardial infarction (STEMI) remains unknown.
Methods: We adapted the Bypass Angioplasty Revascularization Investigation Myocardial Jeopardy Index (BARI-score) to determine the angiographic anatomical extent of jeopardized myocardium within the territory of the culprit lesion in 106 subjects with STEMI. Contrast-enhanced cardiac magnetic resonance was performed acutely to measure the infarct size, and the myocardial salvage index was calculated as the percentage of the jeopardized area that was spared from necrosis.
Results: The BARI-score predicted the acute infarct size in subjects with both absent residual flow and late reperfusion (Fig. A⇓). The presence of collateral Rentrop’s grade ≥ 2 or pre-procedural TIMI flow ≥ 2 were independent predictors of larger degrees of salvage, improved regional wall function, and reduction in infarct transmurality (p < 0.001 for all). Additionally, increasing time to reperfusion was associated with a reduction in myocardial salvage (p < 0.001) and an increase in the number of transmural infarct segments when residual flow was absent (p = 0.017) (Fig. B⇓).
Conclusion: The presence of residual flow to the jeopardized area limits myocardial infarct transmurality and improves salvage during the acute phase of myocardial infarction. This combined angiographic-magnetic resonance approach is a simple and precise clinical tool with widespread clinical applicability to determine myocardial salvage.