Comparison between visual grading and planimetric quantification of microvascular obstruction extent assessment in reperfused acute myocardial infarction

Patterns of left ventricular remodeling post-myocardial infarction, determinants, and outcome

AIM

Left ventricular remodeling (LVR) after myocardial infarction (MI) can lead to heart failure, arrhythmia, and death. We aim to describe adverse LVR patterns at 6 months post-MI and their relationships with subsequent outcomes and to determine baseline.

METHODS AND RESULTS

A multicenter cohort of 410 patients (median age 57 years, 87% male) with reperfused MI and at least 3 akinetic LV segments on admission was analyzed. All patients had transthoracic echocardiography performed 4 days and 6 months post-MI, and 214 also had cardiac magnetic resonance imaging performed on day 4. To predict LVR, machine learning methods were employed in order to handle many variables, some of which may have complex interactions. Six months post-MI, echocardiographic increases in LV end-diastolic volume (LVEDV), LV end-systolic volume (LVESV), and LV ejection fraction (LVEF) were 14.1% [interquartile range 0.0, 32.0], 5.0% [- 14.0, 25.8], and 8.7% [0.0, 19.4], respectively. At 6 months, ≥ 15% or 20% increases in LVEDV were observed in 49% and 42% of patients, respectively, and 37% had an LVEF < 50%. The rate of death or new-onset HF at the end of 5-year follow-up was 8.8%. Baseline variables associated with adverse LVR were determined best by random forest analysis and included stroke volume, stroke work, necrosis size, LVEDV, LVEF, and LV afterload, the latter assessed by Ea or Ea/Ees. In contrast, baseline clinical and biological characteristics were poorly predictive of LVR. After adjustment for predictive baseline variables, LV dilation > 20% and 6-month LVEF < 50% were significantly associated with the risk of death and/or heart failure: hazard ratio (HR) 2.12 (95% confidence interval (CI) 1.05-4.43; p = 0.04) and HR 2.68 (95% CI 1.20-6.00; p = 0.016) respectively.

CONCLUSION

Despite early reperfusion and cardioprotective therapy, adverse LVR remains frequent after acute MI and is associated with a risk of death and HF. A machine learning approach identified and prioritized early variables that are associated with adverse LVR and which were mainly hemodynamic, combining LV volumes, estimates of systolic function, and afterload.

Comparative analysis of late gadolinium enhancement assessment techniques for monitoring fibrotic changes in myocarditis follow-up

OBJECTIVES

To compare the repeatability and interrelation of various late gadolinium enhancement (LGE) assessment techniques for monitoring fibrotic changes in myocarditis follow-up.

MATERIALS AND METHODS

LGE extent change between baseline and 3-month cardiovascular magnetic resonance (CMR) was compared in patients with acute myocarditis using the full width at half maximum (FWHM), gray-scale thresholds at 5 and 6 standard deviations (SD5 and SD6), visual assessment with threshold (VAT) and full manual (FM) techniques. In addition, visual presence score (VPS), visual transmurality score (VTS), and a simplified visual change score (VCS) were assessed. Intraclass-correlation (ICC) was used to evaluate repeatability, and methods were compared using Spearman's correlation.

RESULTS

Forty-seven patients (38 male, median age: 27 [IQR: 21; 38] years) were included. LGE extent change differed among quantitative techniques (p < 0.01), with variability in the proportion of patients showing LGE change during follow-up (FWHM: 62%, SD5: 74%, SD6: 66%, VAT: 43%, FM: 60%, VPS: 53%, VTS: 77%, VCS: 89%). Repeatability was highest with FWHM (ICC: 0.97) and lowest with SD5 (ICC: 0.89). Semiquantitative scoring had slightly lower values (VPS ICC: 0.81; VTS ICC: 0.71). VCS repeatability was excellent (ICC: 0.93). VPS and VTS correlated with quantitative techniques, while VCS was positively associated with VPS, VTS, VAT, and FM, but not with FWHM, SD5, and SD6.

CONCLUSION

FWHM offers the least observer-dependent LGE follow-up after myocarditis. VPS, VTS, and VCS are practical alternatives, showing reliable correlations with quantitative methods. Classification of patients exhibiting either stable or changing LGE relies on the assessment technique.

CLINICAL RELEVANCE STATEMENT

This study shows that LGE monitoring in myocarditis is technique-dependent; the FWHM method yields the most consistent fibrotic tracking results, with scoring-based techniques as reliable alternatives.

KEY POINTS

Recognition of fibrotic changes during myocarditis follow-up is significantly influenced by the choice of the quantification technique employed. The FWHM technique ensures highly repeatable tracking of myocarditis-related LGE changes. Segment-based visual scoring and the simplified visual change score offer practical, reproducible alternatives in resource-limited settings.

Cardiovascular magnetic resonance techniques for tissue characterization after acute myocardial injury

The annual incidence of hospital admission for acute myocardial infarction lies between 90 and 312 per 100 000 inhabitants in Europe. Despite advances in patient care 1 year mortality after ST-segment elevation myocardial infarction (STEMI) remains around 10%. Cardiovascular magnetic resonance imaging (CMR) has emerged as a robust imaging modality for assessing patients after acute myocardial injury. In addition to accurate assessment of left ventricular ejection fraction and volumes, CMR offers the unique ability of visualization of myocardial injury through a variety of imaging techniques such as late gadolinium enhancement and T2-weighted imaging. Furthermore, new parametric mapping techniques allow accurate quantification of myocardial injury and are currently being exploited in large trials aiming to augment risk management and treatment of STEMI patients. Of interest, CMR enables the detection of microvascular injury (MVI) which occurs in approximately 40% of STEMI patients and is a major independent predictor of mortality and heart failure. In this article, we review traditional and novel CMR techniques used for myocardial tissue characterization after acute myocardial injury, including the detection and quantification of MVI. Moreover, we discuss clinical scenarios of acute myocardial injury in which the tissue characterization techniques can be applied and we provide proposed imaging protocols tailored to each scenario.

VEGF-A plasma levels are associated with microvascular obstruction in patients with ST-segment elevation myocardial infarction

BACKGROUND

Microvascular obstruction (MVO) is associated with poor outcome after ST-segment elevation myocardial infarction (STEMI). Vascular endothelial growth factor-A (VEGF-A) is a vascular permeability inducer playing a key role in MVO pathogenesis. We aimed to assess whether VEGF-A levels are associated with MVO, when evaluated by magnetic resonance imaging (MRI) in STEMI patients.

METHODS

The multicenter prospective PREGICA study included a CMR substudy with all consecutive patients with a first STEMI who had undergone cardiac MRI at baseline and at 6-month follow-up. Patients with initial TIMI flow >1 were excluded. VEGF-A levels were measured in blood samples drawn at inclusion.

RESULTS

Between 2010 and 2017, 147 patients (mean age 57 ± 10 years; 84% males) were included. MVO was present in 65 (44%) patients. After multivariate analysis, higher troponin peak (OR 1.005; 95% CI 1.001-1.008; p = 0.007) and VEGF-A levels (OR 1.003; 95% CI 1.001-1.005; p = 0.015) were independently associated with MVO. When considering only patients with successful percutaneous coronary intervention (final TIMI flow 3, n = 130), higher troponin peak (p = 0.004) and VEGF-A levels (p = 0.03) remained independently predictive of MVO. Moreover, MVO was associated with adverse left ventricular (LV) remodeling and VEGF-A levels were significantly and inversely correlated with LV ejection fraction (EF) at 6-month follow-up.

CONCLUSION

Our results show that VEGF-A levels were independently associated with MVO during STEMI and correlated with mid-term LVEF alteration. VEGF-A could therefore be considered as a biomarker of MVO in STEMI patients and be used to stratify patient prognosis.

Society for Cardiovascular Magnetic Resonance (SCMR) expert consensus for CMR imaging endpoints in clinical research: part I - analytical validation and clinical qualification

Cardiovascular disease remains a leading cause of morbidity and mortality globally. Changing natural history of the disease due to improved care of acute conditions and ageing population necessitates new strategies to tackle conditions which have more chronic and indolent course. These include an increased deployment of safe screening methods, life-long surveillance, and monitoring of both disease activity and tailored-treatment, by way of increasingly personalized medical care. Cardiovascular magnetic resonance (CMR) is a non-invasive, ionising radiation-free method, which can support a significant number of clinically relevant measurements and offers new opportunities to advance the state of art of diagnosis, prognosis and treatment. The objective of the SCMR Clinical Trial Taskforce was to summarizes the evidence to emphasize where currently CMR-guided clinical care can indeed translate into meaningful use and efficient deployment of resources results in meaningful and efficient use. The objective of the present initiative was to provide an appraisal of evidence on analytical validation, including the accuracy and precision, and clinical qualification of parameters in disease context, clarifying the strengths and weaknesses of the state of art, as well as the gaps in the current evidence This paper is complementary to the existing position papers on standardized acquisition and post-processing ensuring robustness and transferability for widespread use. Themed imaging-endpoint guidance on trial design to support drug-discovery or change in clinical practice (part II), will be presented in a follow-up paper in due course. As CMR continues to undergo rapid development, regular updates of the present recommendations are foreseen.