In STEMI patients with myocardial blush grade 3, greater culprit lesion expansion by stent was independently associated with reduced myocardial salvage index.
Does over expansion of the culprit lesion during primary PCI impair myocardial salvage in STEMI patients?
Over-expanding stents beyond the reference size during primary PCI for STEMI may impair myocardial salvage, an effect that might be mitigated by the use of distal filter devices.
Abstract Background Slow flow phenomenon is impaired coronary flow during percutaneous coronary intervention (PCI) in absence of mechanical obstruction, and it is associated with deteriorated outcome. Expanding lager of culprit lesion in ACS with stent device increases the risk of slow flow phenomenon. However, the impact of over dilating culprit lesion on cardiac damage in STEMI patients is unclear. Purpose We assessed the hypothesis that over expansion of culprit lesion in STEMI patients assessed with intravascular imaging is associated with myocardial infraction size, evaluated with cardiac magnetic resonance (CMR). Methods STEMI patients who underwent coronary revascularization therapy using intravascular imaging device (Intravascular ultrasound, Optical coherence tomography, Optical frequency domain imaging) and taken CMR at about 4 days and 6 months between 2017 and 2024 were included. We assumed the culprit lesion inner cavity volume of two combined frustums of a cone. We calculated the inner cavity volume of pre stent culprit lesion and post stent culprit lesion. The difference between the post culprit inner cavity and pre culprit inner cavity was estimated as a plaque volume which was displaced by the stent, and we defined the displaced plaque volume as a Culprit expansion volume. We also defined Culprit expansion index as rate of increase in Culprit expansion volume compared to before expansion. Myocardial salvage index was calculated with area at risk using acute phase T2 high volume and chronic phase late gadolinium enhancement volume. Results The median age was 70y interquartile range 62 -75, prevalence of male was 86%, and door-to-balloon time was 59 min 48 -76. ΔLVEDV index and Culprit expansion volume was negatively associated in non-filter device used patients.(Figure 1A) However ,in filter used patients, ΔLVEDV index and Culprit expansion volume showed lowering tendency(Figure 1B). Culprit expansion index was negatively associated with salvage index in MBG3 (Figure 2A). In the multivariate regressive analysis of the salvage index in MBG3 patients, culprit expansion index was found to be independently and significantly correlated (Figure2B). Conclusions In patients ended in final myocardial blush grade 3, expanding stent more than reference size measured with intravascular imaging device may impaired myocardial salvage, and filter device may help to suppress left ventricular remodeling. Further studies are necessary to clarify the effectiveness of filter devices.
Kanegawa et al. (2025) studied this question. In STEMI patients with myocardial blush grade 3, greater culprit lesion expansion by stent was independently associated with reduced myocardial salvage index.