Clinical Outcomes Associated With Various Microvascular Injury Patterns Identified by CMR After STEMI.

BACKGROUND: The prognostic significance of various microvascular injury (MVI) patterns after ST-segment elevation myocardial infarction (STEMI) is not well known. OBJECTIVES: This study sought to investigate the prognostic implications of different MVI patterns in STEMI patients. METHODS: The authors analyzed 1,109 STEMI patients included in 3 prospective studies. Cardiac magnetic resonance (CMR) was performed 3 days (Q1-Q3: 2-5 days) after percutaneous coronary intervention (PCI) and included late gadolinium enhancement imaging for microvascular obstruction (MVO) and T2∗ mapping for intramyocardial hemorrhage (IMH). Patients were categorized into those without MVI (MVO-/IMH-), those with MVO but no IMH (MVO+/IMH-), and those with IMH (IMH+). RESULTS: MVI occurred in 633 (57%) patients, of whom 274 (25%) had an MVO+/IMH- pattern and 359 (32%) had an IMH+ pattern. Infarct size was larger and ejection fraction lower in IMH+ than in MVO+/IMH- and MVO-/IMH- (infarct size: 27% vs 19% vs 18% [P < 0.001]; ejection fraction: 45% vs 50% vs 54% [P < 0.001]). During a median follow-up of 12 months (Q1-Q3: 12-35 months), a clinical outcome event occurred more frequently in IMH+ than in MVO+/IMH- and MVO-/IMH- subgroups (19.5% vs 3.6% vs 4.4%; P < 0.001). IMH+ was the sole independent MVI parameter predicting major adverse cardiovascular events (HR: 3.88; 95% CI: 1.93-7.80; P < 0.001). CONCLUSIONS: MVI is associated with future adverse outcomes only in patients with a hemorrhagic phenotype (IMH+). Patients with only MVO (MVO+/IMH-) had a prognosis similar to patients without MVI (MVO-/IMH-). This highlights the independent prognostic importance of IMH in assessing and managing risk after STEMI.

Relation of plasma neuropeptide-Y with myocardial function and infarct severity in acute ST-elevation myocardial infarction.

BACKGROUND: Acute myocardial infarction is associated with the release of the co-transmitter neuropeptide-Y (NPY). NPY acts as a potent vasoconstrictor and is associated with microvascular dysfunction after ST-elevation myocardial infarction (STEMI). This study comprehensively evaluated the association of plasma NPY with myocardial function and infarct severity, visualized by cardiac magnetic resonance (CMR) imaging, in STEMI patients revascularized by primary percutaneous coronary intervention (PCI). METHODS: In this observational study, we included 260 STEMI patients enrolled in the prospective MARINA-STEMI (NCT04113356) study. Plasma NPY concentrations were measured by an immunoassay 24h after PCI from peripheral venous blood samples. Left ventricular ejection fraction (LVEF), global longitudinal strain (GLS), infarct size (IS) and microvascular obstruction (MVO) were determined using CMR imaging. RESULTS: Median plasma concentrations of NPY were 70 [interquartile range (IQR):35-115] pg/ml. NPY levels above median were significantly associated with lower LVEF (48%vs.52%, p=0.004), decreased GLS (-8.8%vs.-12.6%, p<0.001) and larger IS (17%vs.13%, p=0.041) in the acute phase after infarction as well as after 4 months (LVEF:50%vs.52%, p=0.030, GLS:-10.5vs.-12.9,p<0.001,IS:13%vs.10%,p=0.011). In addition, NPY levels were significantly related to presence of MVO (58%vs.52%, p=0.041). Moreover, in multivariable linear regression analysis, NPY remained significantly associated with all investigated CMR parameters (LVEF:p<0.001,GLS:p<0.001,IS:p=0.003,MVO:p=0.042) independent of other established clinical variables including high-sensitivity cardiac troponin T, pre-interventional TIMI flow 0 and left anterior descending artery as culprit lesion location. CONCLUSION: High plasma levels of NPY, measured 24h after STEMI, were independently associated with lower LVEF, decreased GLS, larger IS as well as presence of MVO, indicating plasma NPY as a novel clinical risk marker post STEMI.

Culprit Lesion Vessel Size and Risk of Reperfusion Injury in ST-Segment Elevation Myocardial Infarction: A Cardiac Magnetic Resonance Imaging Study.

BACKGROUND: Microvascular obstruction (MVO) and intramyocardial hemorrhage (IMH) are well-established imaging biomarkers of failed myocardial tissue reperfusion in patients with ST-segment elevation-myocardial infarction treated with percutaneous coronary intervention. MVO and IMH are associated with an increased risk of adverse outcome independent of infarct size, but whether the size of the culprit lesion vessel plays a role in the occurrence and severity of reperfusion injury is currently unknown. This study aimed to evaluate the association between culprit lesion vessel size and the occurrence and severity of reperfusion injury as determined by cardiac magnetic resonance imaging. METHODS AND RESULTS: Patients (n=516) with first-time ST-segment-elevation myocardial infarction underwent evaluation with cardiac magnetic resonance at 4 (3-5) days after infarction. MVO was assessed with late gadolinium enhancement imaging and IMH with T2* mapping. Vessel dimensions were determined using catheter-based reference. Median culprit lesion vessel size was 3.1 (2.7-3.6) mm. MVO and IMH were found in 299 (58%) and 182 (35%) patients. Culprit lesion vessel size was associated with body surface area, diabetes, total ischemic time, postinterventional thrombolysis in myocardial infarction flow, and infarct size. There was no association between vessel size and MVO or IMH in univariable and multivariable analysis (P>0.05). These findings were consistent across patient subgroups with left anterior descending artery and non-left anterior descending artery infarctions and those with thrombolysis in myocardial infarction 3 flow post-percutaneous coronary intervention. CONCLUSIONS: Comprehensive characterization of myocardial tissue reperfusion injury by cardiac magnetic resonance revealed no association between culprit lesion vessel size and the occurrence of MVO and IMH in patients treated with primary percutaneous coronary intervention for ST-segment-elevation myocardial infarction.

Association of dysglycaemia with persistent infarct core iron in patients with acute ST-segment elevation myocardial infarction.

BACKGROUND: Dysglycaemia increases the risk of myocardial infarction and subsequent recurrent cardiovascular events. However, the role of dysglycaemia in ischemia/reperfusion injury with development of irreversible myocardial tissue alterations remains poorly understood. In this study we aimed to investigate the association of ongoing dysglycaemia with persistence of infarct core iron and their longitudinal changes over time in patients undergoing primary percutaneous coronary intervention (PCI) for acute ST-segment elevation myocardial infarction (STEMI). METHODS: We analyzed 348 STEMI patients treated with primary PCI between 2016 and 2021 that were included in the prospective MARINA-STEMI study (NCT04113356). Peripheral venous blood samples for glucose and glycated hemoglobin (HbA1c) measurements were drawn on admission and 4 months after STEMI. Cardiac magnetic resonance (CMR) imaging including T2 * mapping for infarct core iron assessment was performed at both time points. Associations of dysglycaemia with persistent infarct core iron and iron resolution at 4 months were calculated using multivariable regression analysis. RESULTS: Intramyocardial hemorrhage was observed in 147 (42%) patients at baseline. Of these, 89 (61%) had persistent infarct core iron 4 months after infarction with increasing rates across HbA1c levels (<5.7%: 33%, ≥5.7: 79%). Persistent infarct core iron was independently associated with ongoing dysglycaemia defined by HbA1c at 4 months (OR: 7.87 [95% CI: 2.60-23.78]; p < 0.001), after adjustment for patient characteristics and CMR parameters. The independent association was present even after exclusion of patients with diabetes (pre- and newly diagnosed, n = 16). CONCLUSIONS: In STEMI patients treated with primary PCI, ongoing dysglycaemia defined by HbA1c is independently associated with persistent infarct core iron and a lower likelihood of iron resolution. These findings suggest a potential association between ongoing dysglycaemia and persistent infarct core iron, which warrants further investigation for therapeutic implications.

Cardiac Magnetic Resonance Imaging Versus Computed Tomography to Guide Transcatheter Aortic Valve Replacement: A Randomized, Open-Label, Noninferiority Trial.

BACKGROUND: Computed tomography (CT) is recommended for guiding transcatheter aortic valve replacement (TAVR). However, a sizable proportion of TAVR candidates have chronic kidney disease, in whom the use of iodinated contrast media is a limitation. Cardiac magnetic resonance imaging (CMR) is a promising alternative, but randomized data comparing the effectiveness of CMR-guided versus CT-guided TAVR are lacking. METHODS: An investigator-initiated, prospective, randomized, open-label, noninferiority trial was conducted at 2 Austrian heart centers. Patients evaluated for TAVR according to the inclusion criteria (severe symptomatic aortic stenosis) and exclusion criteria (contraindication to CMR, CT, or TAVR, a life expectancy <1 year, or chronic kidney disease level 4 or 5) were randomized (1:1) to undergo CMR or CT guiding. The primary outcome was defined according to the Valve Academic Research Consortium-2 definition of implantation success at discharge, including absence of procedural mortality, correct positioning of a single prosthetic valve, and proper prosthetic valve performance. Noninferiority was assessed using a hybrid modified intention-to-treat/per-protocol approach on the basis of an absolute risk difference margin of 9%. RESULTS: Between September 11, 2017, and December 16, 2022, 380 candidates for TAVR were randomized to CMR-guided (191 patients) or CT-guided (189 patients) TAVR planning. Of these, 138 patients (72.3%) in the CMR-guided group and 129 patients (68.3%) in the CT-guided group eventually underwent TAVR (modified intention-to-treat cohort). Of these 267, 19 patients had protocol deviations, resulting in a per-protocol cohort of 248 patients (121 CMR-guided, 127 CT-guided). In the modified intention-to-treat cohort, implantation success was achieved in 129 patients (93.5%) in the CMR group and in 117 patients (90.7%) in the CT group (between-group difference, 2.8% [90% CI, -2.7% to 8.2%]; P<0.01 for noninferiority). In the per-protocol cohort (n=248), the between-group difference was 2.0% (90% CI, -3.8% to 7.8%; P<0.01 for noninferiority). CONCLUSIONS: CMR-guided TAVR was noninferior to CT-guided TAVR in terms of device implantation success. CMR can therefore be considered as an alternative for TAVR planning. REGISTRATION: URL: https://www. CLINICALTRIALS: gov; Unique identifier: NCT03831087.

Improved detection of echocardiographically occult left ventricular thrombi following ST-elevation myocardial infarction.

AIM: The aim of this study was to investigate predictors of transthoracic echocardiography (TTE)-occult left ventricular (LV) thrombi (LVT) and to propose a clinical model for improved detection of TTE-occult LVT post-ST-elevation myocardial infarction (STEMI). Patients with acute STEMI are at significant risk for developing LVT. However, this complication often (up to 65%) remains undetected by using TTE, referred to as TTE-occult LVT. METHODS AND RESULTS: In total, 870 STEMI patients underwent TTE and cardiac magnetic resonance (CMR), the reference method for LVT detection, 3 days after infarction. Clinical (body mass index, peak cardiac troponin T) and echocardiographic [ejection fraction, apical wall motion scores (AWMSs)] predictors were analysed. Primary endpoint was the presence of TTE-occult LVT identified by CMR imaging. From the overall cohort, 37 patients (4%) showed an LVT by CMR. Of these thrombi, 25 (68%) were not identified by TTE. Transthoracic echocardiography-occult thrombi did not significantly differ in volume (1.4 vs. 2.74 cm3), diameter (19.0 vs. 23.3 mm), and number of fragments or shape compared with TTE-apparent LVT (all P > 0.05). For predicting these TTE-occult LVT, the 16-segment AWMS (AWMS16Seg) showed highest validity {area under the curve: 0.91 [95% confidence interval (CI): 0.89-0.93]; P < 0.001}, with an association independent of ejection fraction and 17-segment AWMS (AWMS17Seg) [odds ratio: 1.68 (95% CI: 1.43-1.97); P < 0.001] and clinical (body mass index, peak troponin) and angiographic (culprit lesion, post-interventional thrombolysis in myocardial infarction flow) associates of TTE-occult LVT (all P < 0.05). Dichotomization at AWMS16Seg ≥ 8 (n = 260, 30%) allowed for a detection of all TTE-occult LVT (sensitivity: 100%), with a corresponding specificity of 77%. CONCLUSION: After acute STEMI, AWMS16Seg served as a simple and very robust predictor of TTE-occult LVT. An AWMS16Seg-based algorithm to identify patients for additional CMR imaging offers great potential to optimize detection of TTE-occult LVT following STEMI.