Intracoronary ECG during primary percutaneous coronary intervention for ST-segment elevation myocardial infarction
Dennis T L Wong1, Michael C H Leung, Rajiv Das
1Cardiovascular Research Centre, Royal Adelaide Hospital & Discipline of Medicine, University of Adelaide, Adelaide, Australia.
Introduction:
Microvascular obstruction (MVO) following ST-segment elevation myocardial infarction (STEMI) is associated with larger infarct size and an increased mortality. Although angiographic predictors of MVO in primary percutaneous coronary intervention (primary-PCI) setting have been identified, an earlier and objective "in-lab" predictor may be beneficial, in order to potentially influence therapies administered during primary-PCI. We hypothesised that intracoronary-electrocardiogram (IC-ECG) is a simple, objective and accurate predictor of MVO evaluated by cardiac magnetic resonance (CMR) and is comparable to myocardial blush grade (MBG) and TIMI myocardial perfusion grade (TMPG).
Method:
Intracoronary ECG was performed during primary-PCI. Intracoronary ST-segment measurement was performed before and immediately after opening of infarct-related-artery. Intracoronary ST-segment resolution (IC-STR) was defined as ≥ 1 mm improvement compared to baseline. Contrast enhanced CMR was performed at 4 and 90 days post primary-PCI. Primary endpoint was MVO on late gadolinium hyperenhancement assessed by CMR at day 4.
Results:
Sixty-four consecutive patients (age 59 ± 11 years; 55 males) were recruited. Intracoronary ST-segment resolution correlated with MVO (p=0.005). Furthermore, IC-STR correlated with infarct-mass, non-viable-mass, peak creatinine kinase and end-systolic-volume at day 4. Intracoronary ST-segment resolution also correlated with favourable left ventricular end-diastolic-volume at day 90 (p=0.022). On multivariate analysis, IC-STR was an independent predictor of MVO.
Conclusion:
Intracoronary ST-segment resolution is a strong in-lab predictor of MVO assessed 4 days after STEMI on CMR. Furthermore, IC-STR correlates with infarct size and left ventricular remodelling at 3 months. Further studies are required to understand potential clinical utility of this tool.
Insights
Intracoronary ST-segment resolution (IC-STR) effectively predicts microvascular obstruction (MVO) after ST-elevation myocardial infarction (STEMI). This simple in-lab tool correlates with infarct size and ventricular remodeling, aiding early therapeutic decisions.
Area of Science:
- Cardiology
- Interventional Cardiology
- Cardiovascular Imaging
Background:
- Microvascular obstruction (MVO) post-STEMI is linked to adverse outcomes.
- Current angiographic predictors lack early in-lab objectivity.
- Intracoronary-ECG (IC-ECG) offers a potential objective predictor.
Purpose of the Study:
- To evaluate IC-ECG as an early predictor of MVO.
- To compare IC-ECG with established perfusion markers (MBG, TMPG).
- To assess IC-ECG's correlation with infarct size and ventricular remodeling.
Main Methods:
- IC-ECG performed during primary PCI, measuring ST-segment resolution (IC-STR).
- Cardiac MRI (CMR) used to assess MVO at day 4 and 90.
- Correlation analysis between IC-STR and CMR-derived MVO, infarct mass, and ventricular volumes.
Main Results:
- IC-STR was a significant predictor of MVO (p=0.005).
- IC-STR correlated with infarct mass, peak CK, and end-systolic volume at day 4.
- IC-STR also predicted favorable LV end-diastolic volume at day 90 (p=0.022).
Conclusions:
- IC-STR is a strong in-lab predictor of MVO post-STEMI.
- IC-STR correlates with infarct size and LV remodeling at 3 months.
- Further research is needed to define the clinical utility of IC-STR.
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