BACKGROUND Data on the prognostic value of the shock index in patients with ST-elevation myocardial infarction (STEMI) are scarce. Furthermore, the relationship of the shock index with myocardial damage is unknown. The aim of this study was to evaluate the association of the shock index with markers of myocardial damage and clinical outcome in patients with STEMI. METHODS AND RESULTS This multicenter study analyzed 791 patients. Patients were categorized in 2 groups according to the admission shock index (optimized cut-off=0.62). Infarct severity was determined by cardiac magnetic resonance (CMR) imaging. Patients with cardiogenic shock that were unable to undergo CMR acquisition were excluded. Major adverse cardiac events (MACE) were defined as a composite of death, reinfarction and congestive heart failure within 12 months. Patients with elevated admission shock index (n=321 [40.6%]) had a significantly larger area-at-risk (37.6 [27.8-50.4] % of left ventricular volume [LV] vs. 34.3 [24.5-46.0] % LV, P=0.02), larger infarct size (19.5 [10.7-28.0] % LV vs. 14.9 [7.7-22.3] % LV, P<0.001), lower myocardial salvage index (46.2 [27.9-64.5] vs. 53.5 [36.5-75.2], P<0.001), and a larger extent of microvascular obstruction (0.3 [0.0-2.2] % LV vs. 0.0 [0.0-1.4] % LV, P=0.01). An elevated shock index was associated with reduced MACE-free survival (P<0.001). Furthermore, the admission shock index was identified as an independent predictor of MACE (hazard ratio=2.92 [1.24-4.22], P<0.01). CONCLUSIONS STEMI patients with an elevated admission shock index had more pronounced myocardial and microvascular damage. Moreover, the shock index was independently associated with MACE at 12 months.

Shock Index as a Predictor of Myocardial Damage and Clinical Outcome in ST-Elevation Myocardial Infarction.

Cardiac magnetic resonance (CMR) is the gold-standard modality for the assessment of left ventricular (LV) remodeling in ST-elevation myocardial infarction (STEMI) patients. However, the commonly used remodeling criteria have never been validated for hard clinical events. We therefore aimed to define clear CMR criteria of LV remodeling following STEMI with proven prognostic impact. This observational study included 224 patients suffering from acute STEMI. CMR was performed within 1 week and 4 months after infarction to evaluate different remodeling criteria including relative changes in LV end-diastolic volume (%∆LVEDV), end-systolic volume (%∆LVESV), ejection fraction (%∆LVEF), and myocardial mass (%∆LVMM). Primary endpoint was the occurrence of major adverse cardiovascular events (MACE) including all-cause death, re-infarction, stroke, and new congestive heart failure 24 months following STEMI. Secondary endpoint was defined as composite of primary endpoint and cardiovascular hospitalization. The Mann–Whitney U test was applied to assess differences in LV remodeling measures between patients with and without MACE. Values for the prediction of primary and secondary endpoints were assessed by c-statistics and Cox regression analysis. The incidence of MACE (n = 13, 6%) was associated with higher %∆LVEDV (p = 0.002) and %∆LVMM (p = 0.02), whereas %∆LVESV and %∆LVEF were not significantly related to MACE (p > 0.05). The area under the curve (AUC) for the prediction of MACE was 0.76 (95% confidence interval [CI], 0.65–0.87) for %∆LVEDV (optimal cut-off 10%) and 0.69 (95%CI, 0.52–0.85) for %∆LVMM (optimal cut-off 5%). From all remodeling criteria, %∆LVEDV ≥ 10% showed highest hazard ratio (8.68 [95%CI, 2.39–31.56]; p = 0.001) for MACE. Regarding secondary endpoint (n = 35, 16%), also %∆LVEDV with an optimal threshold of 10% emerged as strongest prognosticator (AUC 0.66; 95%CI, 0.56–0.75; p = 0.004). Following revascularized STEMI, %∆LVEDV ≥ 10% showed strongest association with clinical outcome, suggesting this criterion as preferred CMR-based definition of post-STEMI LV remodeling. • CMR-determined %∆LVEDV and %∆LVMM were significantly associated with MACE following STEMI. • Neither %∆LVESV nor %∆LVEF showed a significant relation to MACE. • %∆LVEDV ≥ 10 was revealed as LV remodeling definition with highest prognostic validity.

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Prognosis-based definition of left ventricular remodeling after ST-elevation myocardial infarction

Cardiac magnetic resonance (CMR) imaging allows comprehensive assessment of myocardial function and tissue characterization in a single examination after acute ST-elevation myocardial infarction. Markers of myocardial infarct severity determined by CMR imaging, especially infarct size and microvascular obstruction, strongly predict recurrent cardiovascular events and mortality. The prognostic information provided by a comprehensive CMR analysis is incremental to conventional risk factors including left ventricular ejection fraction. As such, CMR parameters of myocardial tissue damage are increasingly recognized for optimized risk stratification to further ameliorate the burden of recurrent cardiovascular events in this population. In this review, we provide an overview of the current impact of CMR imaging on optimized risk assessment soon after acute ST-elevation myocardial infarction.

https://www.mdpi.com/2077-0383/9/4/1041/pdf

Role of Cardiac Magnetic Resonance to Improve Risk Prediction Following Acute ST-Elevation Myocardial Infarction.

BackgroundMicrovascular injury (MVI) after primary percutaneous coronary intervention for ST‐elevation myocardial infarction (STEMI) is a major determinant of adverse clinical outcome. Experimental...

Relation of Low-Density Lipoprotein Cholesterol With Microvascular Injury and Clinical Outcome in Revascularized ST-Elevation Myocardial Infarction.

Major adverse cardiovascular events (MACE) remain the major cause of mortality and morbidity in patients with STEMI (ST-elevation myocardial infarction). The current literature is aimed to analyze the occurrence of MACE following STEMI irrespective of treatment provided, and follow up after the first diagnosis of STEMI. A PubMed search for Studies of STEMI identified 24,244 articles. After applying our inclusion/exclusion criteria, we found out 75 articles of relevance wherein MACE and its components were considered to be the primary endpoint. These 75 articles included eight Cohort Studies, 13 clinical trials including five randomized controlled trials (RCT), one case-control Study, one cross-sectional study, one review article, and 51 other observational studies. Our analysis shows that MACE remains one of the strongest adverse outcomes among STEMI patients. The current literature review found out the incidence of MACE was 4.2 % to 51% irrespective of the mode of treatment, and follow-ups lasting up to 10 years from the time of STEMI diagnosis.

Major Adverse Cardiovascular Events: An Inevitable Outcome of ST-elevation myocardial infarction? A Literature Review.

Aims The left ventricular global function index (LVGFI) is a novel indicator of left ventricular performance. Its prognostic value in patients after ST-segment elevation myocardial infarction (STEMI) is unknown. We sought to evaluate the prognostic significance of LVGFI measured by cardiovascular magnetic resonance (CMR) imaging after STEMI.

Methods and results Two hundred eligible STEMI patients (56 ± 11 years, 16% female) revascularized by primary percutaneous coronary intervention were followed-up for 3.1 [2–4.1] years for major adverse cardiac events (MACE). MACE was defined as a composite of death, non-fatal myocardial re-infarction, and new congestive heart failure. All patients underwent CMR imaging within 2 [2–4] days after STEMI. Late enhancement and cine images were acquired to assess myocardial injury as well as myocardial function, including LVGFI. Patients suffering a MACE event ( n = 20, 10%) had a significantly lower LVGFI ( P = 0.001). In Kaplan–Meier analysis, a decreased LVGFI was associated with a reduced MACE-free survival ( P < 0.001). Multivariate Cox regression analysis revealed a decreased LVGFI as a predictor for MACE [hazard ratio = 4.79, 95% confidence interval (CI) 1.46–15.67, P = 0.010] after adjusting for microvascular obstruction, left ventricular mass, and multivessel disease. In receiver operating characteristic analysis, LVGFI was a strong predictor for MACE (area under the curve = 0.73, CI 0.61–0.85). However, c -statistics revealed that LVGFI does not provide incremental prognostic information over left ventricular ejection fraction (LVEF) ( P = 0.38).

Conclusion LVGFI assessed by CMR is a strong predictor of MACE within 3 years after first STEMI. A superior predictive value as compared with LVEF was not found in this study.

Bastian Pernter

Papers

Prognostic value of left ventricular global function index in patients after ST-segment elevation myocardial infarction.