Worst lead ST deviation and resolution of ST elevation at one hour for prediction of myocardial salvage, infarct size, and microvascular obstruction in patients with ST-elevation myocardial infarction treated with primary percutaneous coronary intervention

Correlations between clinical and laboratory findings and prognostically unfavorable CMR-based characteristics of acute ST-elevation myocardial infarction

Aim To evaluate factors associated with unfavorable predictive characteristics of ST-segment elevation acute myocardial infarction (STEMI) as per data of magnetic resonance imaging (MRI).Material and methods The study included 52 patients with STEMI who underwent a primary percutaneous coronary intervention (pPCI). Contrast-enhanced cardiac MRI was performed for all patients on days 3-7. Delayed contrast-enhancement images were used for assessing infarct size, presence of microvascular obstruction (MVO) areas, and heterogeneity zones.Results Multifactorial analysis showed that independent predictors of MVO were type 2 diabetes mellitus (DM) (relative risk (RR) 1.9, confidence interval (CI): 1.1-3.26, р=0.012), increased levels of brain natriuretic peptide (BNP) (RR 2.04, CI: 1.39-2.99, р=0.004) and creatine kinase (CK) (RR 2.06, CI: 0.52-0.80, р=0.02), and infarct size (IS) (RR 2.81; CI: 1.38-5.72, р=0.0004). Construction of ROC curves provided the quantitative values of study indexes, at which the risk of MVO increased. For BNP, this value was ≥276 pg/ml (sensitivity, 95.7 %; specificity, 37.9 %); for CK ≥160 U/l (sensitivity, 74.1 %; specificity, 61.9 %); and for IS ≥18.8 % (sensitivity, 79.3 %; specificity, 69.6 %). Correlation analysis of risk factors for increased size of the heterogeneity zone showed significant correlations of the heterogeneity zone size with older age of patients (r=0.544, р<0.0001), higher concentrations of BNP (r=0.612, р<0.0001), CK (r=0.3, 95 % CI: 0.02-0.5, р=0.03), and C-reactive protein (CRP) (r=0.59, CI: 0.3-0.7, р=0.0001). Increased levels of CK (r=0.53, 95 % CI: 0.29-0.70, р=0.0001) and BNP (r=0.55, 95 % CI: 0.28-0.70, p=0.0003) significantly correlated with increased IS.Conclusion Risk of MVO formation as per MRI data increased in the presence of type 2 DM and IS ≥18.8 % (р<0.05). Formation of MVO in patients with STEMI was associated with increased levels of BNP ≥276 pg/ml and CK ≥160 U/l (р<0.05). Increased levels of BNP, CK, and CRP were associated with a larger size of heterogeneity zone according to data of the correlation analysis. A larger heterogeneity zone was more typical for older patients. Increased levels of CK and BNP were also associated with larger IS. The correlation analysis did not show any significant interactions between the size of heterogeneity zone, IS, and MVO size (р>0.05).

Worst lead ST deviation and resolution of ST elevation at one hour for prediction of myocardial salvage, infarct size, and microvascular obstruction in patients with ST-elevation myocardial infarction treated with primary percutaneous coronary intervention

Background

ECG changes after revascularization predicts improved outcome for patients with ST‐elevation myocardial infarction (STEMI). Worst lead residual (WLR) ST deviation and resolution of worst lead ST elevation (rST elevation) are simple measures that can be obtained early after PCI. The objective of the current study was to investigate whether simple ECG measures, obtained one hour following PCI, could predict cardiac magnetic resonance (CMR)‐derived myocardial salvage index (MSI), infarct size (IS), and microvascular obstruction (MVO) in patients with STEMI included in the MITOCARE trial.

Methods

The MITOCARE trial included 165 patients with a first‐time STEMI presenting within six hours of symptom onset. The current analysis included patients that had an ECG recorded at baseline and one hour after PCI and underwent CMR imaging after 3–5 days. Independent core laboratories determined WLR ST deviation, rST elevation, and the CMR variables (MSI, IS, and MVO).

Results

83 patients with a mean age of 61 years were included. 83.1% were males and 41% had anterior infarctions. In logistic regression models, WLR ST deviation was a statistically significant predictor of IS (OR 2.2, 95% CI 1.3–3.8) and MVO (OR 2.8, 95% CI 1.5–5.2), but not of MSI (OR 0.8, 95% CI 0.5–1.2). rST elevation showed a trend toward a significant association with IS (OR 0.3, 95% CI 0.1–1.0), but not with the other CMR variables.

Conclusion

WLR ST deviation one hour after PCI was a predictor of IS and MVO. WLR ST deviation, a measure easily obtained from ECGs following PCI, may provide important prognostic information in patients with STEMI.