Novel insights on acute myocarditis in pediatric patients

Acute myocarditis (AM) is an inflammatory affliction of the heart muscle characterized by recent onset with a broad spectrum of clinical manifestations that globally affect millions of individuals, notably children and young adults. The absence of distinct patterns of onset or predictable progression poses a significant threat to survival, potentially leading to advanced heart failure and malignant arrhythmias. Myocardial fibrosis, a hallmark of myocardial remodeling, is increasingly recognized as a contributor to adverse outcomes in acute myocarditis cases. Advances in molecular and immunological techniques have highlighted the intricate interplay between viral infections, dysregulated immune responses, and genetic susceptibility. Currently, there is no clear consensus for diagnosis or ongoing follow-up in pediatric patients. The conventional diagnostic tool, endomyocardial biopsy (EMB), considered the gold standard, has been complemented by the effectiveness of cardiac magnetic resonance imaging (CMRI) techniques. Given the procedural complexities and associated complications, there is a pressing need to explore non-invasive alternatives. In this context, biomarkers emerge as promising contenders by evaluating both the inflammatory processes and cardiac remodeling, providing valuable observations into disease severity, progression, and treatment response. Therapeutic strategies in these cases, focusing on the specific pathways or immune components associated with the etiologies, have exhibited promise for better outcomes. Acute myocarditis in children remains a multifaceted clinical challenge, necessitating a comprehensive understanding of its pathophysiology, diagnosis, and management. This review aims to delve into novel insights surrounding the pathophysiology, diagnosis, and management of acute myocarditis in pediatric patients.

Evaluation and implications of mitral regurgitation using cMRI in patients with hypertrophic cardiomyopathy

OBJECTIVE

Mitral regurgitation (MR) represents an important feature in patients with hypertrophic cardiomyopathy (HCM) due to left ventricular outflow tract (LVOT) obstruction and mitral valve systolic anterior motion (SAM). Mitral valve anatomical variants associated with HCM also contribute to the severity of MR. The aim of this study is to evaluate MR severity and its correlation with different parameters in patients with HCM using cardiac magnetic resonance imaging (cMRI).

PATIENTS AND METHODS

130 patients with HCM underwent cMRI. Parameters assessed for the quantification of MR severity were mitral regurgitation volume (MRV) and mitral regurgitation fraction (MRF). cMRI was also used to characterize LV function, left atrium volume (LAV) index, filling pressures and structural abnormalities associated with HCM, all in correlation to MR.

RESULTS

Patients with HCM had mild (26.9%), moderate (52.3%) or severe (20.7%) MR. Most relevant parameters related to MR severity were MRV and MRF; other parameters with strong correlation with MR were LAV index and E/E' ratio, both increasing with its severity. Patients with LVOT obstruction had more severe MR (70.3%), 79% of them due to SAM. LV ejection fraction (LVEF) increased proportionally with the severity of MR, while LV strain (LAS) was inversely correlated with it. Independent predictors for quantifying the severity of MR, after the adjustment for covariates, were MRV, MRF, SAM, LAV index and E/E'.

CONCLUSIONS

cMRI can accurately assess MR in patients with HCM, especially by using novel indicators, MRV and MRF respectively, along with LAV index and E/E' ratio. Severe MR, due to SAM, is more frequent in the obstructive form of HCM (HOCM). Also, the severity of MR is significantly associated with significantly associated with MRV, MRF, LAV index and E/E' ratio.

The joint role of collagen turn-over biomarkers and late gadolinium enhancement to predict cardiovascular outcome in nonischemic dilated cardiomyopathy

Background

Myocardial scarring is a primary pathogenetic process in nonischemic dilated cardiomyopathy (NIDCM) which is responsible for progressive cardiac remodeling and heart failure, severely impacting the survival of these patients. Although several collagens turn-over biomarkers have been associated with myocardial fibrosis, their clinical utility is still limited. Late gadolinium enhancement (LGE) determined by cardiac magnetic resonance imaging (CMR) has become a feasible method to detect myocardial replacement fibrosis.

Purpose

We sought to evaluate the association between collagen turn-over biomarkers and replacement myocardial scarring by CMR and, also, to test their ability to predict outcome in conjunction with LGE in patients with NIDCM.

Method

We conducted a prospective study on 194 patients (48.7±14.3 years of age; 74% male gender) with NIDCM. CMR was used to determine the presence and extent of LGE. Several collagen turn-over biomarkers were determined at the diagnosis, comprising galectin-3 (Gal3), procollagen type I carboxy-terminal pro-peptide (PICP) and N-terminal pro-peptide of procollagen type III (PIIINP). A composite outcome (all-cause mortality, ventricular tachyarrhythmias, heart failure hospitalization) was ascertained over a median of 26 months. Of all, 17% (n=33) of patients reached the outcome: all-cause mortality (n=6), malignant ventricular tachyarrhythmia (n=14) and HF hospitalization (n=13).

Results

Gal3, PICP and PIIINP were considerably increased in those with LGE+ (p<0.001), being also directly correlated with LGE mass (r2=0.42; r2=0.44; r2=0.31; all p<0.001). Receiver operating characteristic (ROC) analysis revealed significant ability to diagnose LGE, with area under the ROC: 0.816 for Gal3, 0.705 for PICP, and 0.757 for PIIINP (all p<0.0001). Kaplan-Meier analysis showed that at a threshold of >13.8 ng/dL for Gal3 and >97 ng/dL for PICP, they significantly predicted the outcome (HR=2.66, p<0.001; HR=1.93, p<0.002). Moreover, for a combined model of LGE+/Gal3+/PICP+, time-to-event analysis demonstrated the highest ability to predict composite outcome, as compared to any other models (p=0.004). Nevertheless, in multivariate analysis, after adjustment for covariates, only LGE+ and Gal3+ remained independent predictors for outcome (p=0.008; p=0.04).

Conclusion

In patients with NIDCM, serum collagen turn-over biomarkers such as Gal3, PICP and PIIINP are closely related to the presence and extent of LGE and can significantly predict cardiovascular outcome. The joint use of LGE with Gal3 and PICP significantly improved outcome prediction.

Funding Acknowledgement

Type of funding sources: None.

Characterization of left atrial geometry and function in patients with hypertrophic cardiomyopathy: a cardiac magnetic resonance imaging study

OBJECTIVE

Left atrial (LA) remodelling is an interesting pathological aspect in hypertrophic cardiomyopathy (HCM) which has not been yet fully understood. Also, a comprehensive evaluation of LA alterations in HCM is still lacking. Cardiac magnetic resonance imaging (cMRI) can precisely characterize LA function and structure. We sought to thoroughly assess LA remodelling using cMRI in patients with HCM.

PATIENTS AND METHODS

We enrolled 105 patients with HCM and 105 healthy controls. LA parameters determined by cMRI comprise LA volume (LAV), total ejection fraction (LATF), total strain LA- εt, passive ejection fraction (LAPF), passive strain LA-εe, active ejection fraction (LAAF), active strain LA-εa. LA sphericity index (LASI) and LA strain were also determined. Parameters of LV systolic and diastolic functions were also assessed.

RESULTS

LAV and LASI were significantly increased, while LA phasic functions were decreased in patients with HCM (p<.001). LATF was inversely correlated with LV long-axis strain (r= -0.466, p<.0001) and mass (r= -0.515, p<.0001), and as well with filling pressures, described by E/E' (r= -0.424, p<.0001). LA volumes, phasic functions and geometry were negatively associated with LV measurements, whereas a positive correlation between the LATF and LA strain (r = 0.496, p<.0001) was found. In addition, LAV was closely related to diastolic dysfunction severity (p<.0001).

CONCLUSIONS

In patients with HCM, all three LA phasic functions were impaired, being directly related to LA enlargement. LASI and LA strain predicted LA reservoir function impairment.

Aging influences pulmonary artery flow and stiffness in healthy individuals: non-invasive assessment using cardiac MRI

AIM

To investigate age-related changes of the pulmonary artery (PA) using cardiac magnetic resonance imaging (cMRI) in healthy subjects.

MATERIALS AND METHODS

A cross-sectional observational study was conducted on apparently healthy subjects who underwent PA velocity-encoded cMRI. cMRI was used to determine PA stiffness parameters such as PA elasticity, relative area change (PA-RAC) and pulse-wave velocity (PA-PWV), and PA flow parameters by subtracting simultaneous forward flow (FF) and backward flow (BF) velocity across the PA cross-section. Data were presented in five age and sex matched groups.

RESULTS

One hundred and fifty subjects (20-70 years, 75 men) met the enrolment criteria. PA elasticity and PA-RAC significantly decreased with age (p<0.001), while PA-PWV, regurgitant volume (V_reg) and backward flow volume (V_BF) increased in the elderly (p<0.001). Linear regression analysis indicated that PA elasticity (r=-0.441, p<0.0001) and PA-RAC (r=-0.484, p<0.0001) were indirectly and negatively associated with advancing age, whereas PA_min (r=0.331, p<0.0001), PA-PWV (r=0.490, p<0.0001), V_Reg (r=0.335, p<0.0001) and V_BF (r=0.349, p<0.0001) were directly associated with age. Multivariate analysis indicated that age was independently associated with V_reg and V_BF, and the addition of PA_min and PA-PWV marginally increased its predictive capacity.

CONCLUSION

Aging significantly increases cMRI-based PA flow and stiffness parameters. These could become relevant markers of subclinical changes of the PA geometry in healthy subjects.

Role of pentraxin-3 in risk assessment of patients with metabolic syndrome

BACKGROUND

Inflammation plays a major role in the development of metabolic syndrome (MetS) and its progression. Recent studies have shown that pentraxin-3 (PTX-3), osteoprogerin (OPG), and tumor necrosis factor-alpha (TNF-α) are key factors in MetS pathophysiology, but evidence for endorsing their clinical use is currently unclear and insufficient.

AIM

The study aimed to evaluate the association between the inflammatory biomarkers' levels and the severity of MetS.

METHODS

The study was observational, transversal, prospective, cohort, and analytical type. We enrolled 80 patients (M:F = 1, mean age = 55 ± 10.77 years) who met MetS criteria. The study protocol included: medical history, physical examination, 6-min walk test distance (6MWTD), biochemical tests, electrocardiogram, echocardiography, and carotid ultrasonography. We also performed plasmatic measurement of PTX-3, OPG, and TNF-α, in addition to standard biochemical tests.

RESULTS

Subjects with severe MetS had higher values of body mass index (BMI) and waist circumference (p < 0.001, p = 0.001). PTX-3 levels were significantly higher in patients with severe MetS (p = 0.03) and the values were not influenced by age or gender. OPG positively correlated with BMI (r = 0.264, p = 0.018). 6MWTD was lower in patients with severe MetS (p = 0.005), whereas CCA-IMT was higher in this group of patients (p = 0.005). In addition, the receiver operating characteristic (ROC) curve analysis for PTX-3 identified a cut-off value of 10.7 ng/dl that differentiates between mild and severe MetS [AUC 0.656; sensitivity =47.1% (95% CI = 36.1%-62.3%); specificity = 78.9% (95% CI = 54.4%-93.9%)].

CONCLUSION

PTX-3 was correlated with the severity of MetS, with other inflammatory parameters and cardiovascular tests. CCA-IMT and 6MWTD are useful in differentiating between mild and severe MetS.