Cardiac Cardiovascular Magnetic Resonance Research Articles

Cardiac MRI prediction of recovery in children with acute myocarditis

Myocarditis, defined as inflammation of myocardial tissue, is a rare disease in the pediatric population. Cardiovascular cardiac magnetic resonance (CMR) is a powerful tool for noninvasive assessment of myocardial inflammation as defined by the Lake Louise criteria, with a sensitivity of approximately 82% [1] . CMR allows tissue characterization of the myocardium, as well as accurate definition of ventricular volumes and function. Few prognostic factors have been associated with either normalization of function or progression to dilated cardiomyopathy in pediatric myocarditis. In the present study, we aimed to describe CMR findings in a large cohort of pediatric patients with acute myocarditis and to assess disease evolution. Our study received the proper ethical oversight [CNIL (Commission nationale de l’informatique et des libertés) declaration 2130271 v 0]. Sixty-eight children younger than 18 years of age with clinical myocarditis and positive acute-phase myocardial inflammation, as defined by the Lake Louise criteria [2] , underwent follow-up CMR during a 12-year period (from March 2007 to March 2019). The first follow-up CMR study was performed at a median of 5 months after the first examination (interquartile range: 1 to 6 months), and additional CMR studies were performed in 47% of the cohort (32 patients). Patient characteristics are presented in Table 1 . Most of the cohort were males (73.5%) who presented with chest pain (68%) or new-onset heart failure (33%). Fever was found in 55% of the cohort. Full recovery from acute myocarditis, as defined by normalization of ventricular function [left ventricular ejection fraction (LVEF) > 55%, right ventricular EF > 54%], ventricular dimensions (LV end-diastolic volume index < 104 ml/m 2 for males, < 95 ml/m 2 for females, right ventricular end-diastolic volume index < 108 ml/m 2 for males, < 94 ml/m 2 females), regional wall function and tissue abnormalities [absent myocardial edema and late gadolinium enhancement (LGE)], was observed in 26% of the cohort ( n ¼ 18). Fever at presentation was significantly more common in the patients who had full recovery (100% vs. 43%; P < 0.01). Although baseline LV function was not different between those who had full recovery and those who did not, a non-significantly larger LV volume (79 ml/m 2 vs. 89 ml/m 2 ) was found in those who did not recover. Concerning tissue characterization parameters, positive T2 (90% vs. 77%) and LGE (96% vs. 83%) were significantly more common in patients who did not recover. Early gadolinium enhancement followed the same pattern, without statistical significance. The prevalence of a sub-epicardial pattern of LGE was not different between groups ( P ¼ 0.11), but other LGE patterns were more frequent in patients who did not recover ( P ¼ 0.04). Conversely, acute-phase LGE extent did not differ between groups (4% vs. 3.9%; P ¼ 0.85). To the best of our knowledge, this was the largest multicenter pediatric study that assessed repeated CMR evaluation of acute myocarditis. In the present study, we confirmed the recent finding that LGE in the acute phase of myocarditis was not necessarily a marker of fibrosis. In our population, LGE disappeared completely in 26% of patients, which was higher than the 10% reported in adults [3] . This difference might translate to a higher healing ability of pediatric patients from tissue damage, as seen in other medical conditions. This complete healing of myocardial tissue abnormalities might be clinically relevant because residual fibrosis was associated with worse prognosis independently of LVEF [3] , [4] . In our study, an LGE pattern other than sub-epicardial was associated with non-recovery. This result was concordant with a recent study by Aquaro et al. [5] , who demonstrated a worse prognosis in association with a mid-wall septal pattern of LGE compared with a sub-epicardial inferior-lateral pattern. In conclusion, we found that fever at presentation was associated with full recovery from acute myocarditis, whereas specific acute-phase CMR findings (positive T2 criteria, LGE presence, and patterns other than sub-epicardial) were associated with its absence.

Feature Tracking Myocardial Strain Incrementally Improves Prognostication in Myocarditis Beyond Traditional CMR Imaging Features

ObjectivesThis study investigated the association of cardiovascular cardiac magnetic resonance (CMR) feature tracking (FT) with outcome in a patient cohort with myocarditis and evaluated the possible incremental prognostic benefit beyond clinical features and traditional CMR features. BackgroundCMR is used to diagnose and risk stratify patients with myocarditis. CMR-FT allows quantitative strain analysis of myocardial function; however, its prognostic benefit in myocarditis is unknown. MethodsConsecutive patients with clinically suspected myocarditis and presence of midmyocardial or epicardial late gadolinium enhancement (LGE) and/or myocardial edema in CMR were included. Clinical and CMR features were analyzed with regard to major adverse cardiovascular events (MACE) (i.e., hospitalization for heart failure, sustained ventricular tachycardia, and all-cause mortality). ResultsOf 740 patients with clinically suspected myocarditis, 455 (61%) met our final diagnostic criteria based on CMR tissue characterization. At a median follow-up of 3.9 years, MACE occurred in 74 (16%) patients. In the univariable analysis, CMR-FT global longitudinal peak strain (GLS) was significantly associated with MACE. In a multivariable model adjusting for clinical variables (age, sex, body mass index, and acuteness of symptoms) and traditional CMR features (left ventricular ejection fraction [LVEF] and LGE extent), GLS remained independently associated with outcome (GLS hazard ratio: 1.21; 95% confidence interval: 1.08 to 1.36; p = 0.001) and incrementally improved prognostication (chi-square increases from 42.6 to 79.8 to 88.5; p < 0.001). ConclusionsMyocardial strain using CMR-FT provides independent and incremental prognostic value over clinical features, LVEF, and LGE in patients with myocarditis. CMR-FT may serve as a novel marker to improve risk stratification in myocarditis. (CMR Features in Patients With Suspected Myocarditis [CMRMyo]; NCT03470571)

Cardiac Iron Overload Assessed by T2* Magnetic Resonance (CMR) In Thalassemia Major Patients Treated with Different Iron Chelators

AbstractAbstract 4275 Introduction.Although iron chelation therapy has markedly improved the survival, heart failure due to myocardial iron overload still remains the leading cause of morbidity and mortality in adult thalassemia major (TM) patients. T2* cardiovascular magnetic resonance (CMR) is a non invasive technique that provides rapid and direct assessment of myocardial iron content and its usefulness in monitoring iron chelation has been proved (Wood et al, Circulation 2009). AIM OF THE STUDY. To evaluate the efficacy of different iron-chelation therapies on removal of cardiac iron content assessed by CMR in adult TM patients. PATIENTS AND METHODS. Sixty-seven TM patients (27 males/40 women, mean age 35 ± 6 yrs) treated with different iron chelators underwent repeated cardiac CMR to assess myocardial iron load. Myocardial T2* was assessed at baseline (t0), after 6–14 months (t1) (according to clinical conditions and to T2* at baseline), and as second control (t2) after a mean of 32±7 months from baseline. CMR was performed at Cardiology and CMR Department “A. De Gasperis” at Niguarda Ca' Granda Hospital in Milan, using a 1.5 Tesla MR scanner (Avanto Siemens, Erlangen). Normal cardiac T2* was defined > 20 ms; T2* < 10 ms indicated severe cardiac siderosis and T2* between 10 and 20 ms moderate-to-mild cardiac siderosis. Each patient has to be chelated with the same iron chelation therapy at least for 1 year before the baseline CMR evaluation. Patients were divided based on chelation therapy in 4 groups: group A (n=36, 53.7 %) patients chelated with deferasirox (DFX, mean actual dose 27±7 mg/Kg/die), group B (n=15, 22.4 %) deferoxamine (DFO, actual mean dose 48±9 mg/kg for a median of 6 days/week), group C (n=12, 17,9 %) DFO (mean actual dose 46±7 mg/kg for a median of 4 days/week) plus deferiprone (DFP, mean actual dose 73±7 mg/kg/day) and group D (n=4,6 %) only DFP (mean actual dose 75±0 mg/kg/day). Statistical analysis was performed using a paired Student's t-test. RESULTS. Overall, the pre-transfusional mean hemoglobin (Hb) was 9.7±0.5 g/dl, the median ferritin value was 913 ng/ml (range 229–5934 ng/ml) and the mean iron intake was 0.41±0.12 mg/Kg/day. In the overall population, the baseline myocardial T2* was < 10 ms in 8 patients (11.9 %), between 10 and 20 ms in 22 patients (32.8 %) and ≥ 20 ms in 37 patients (55.2 %). At baseline evaluation, T2* < 10 ms was detected only in 1 patient (1/36: 2.77 %) in group A, in 4 patients (4/15: 26.6 %) in group B and in 3 patients (3/12: 25 %) in group C. In group D all patients showed a myocardial T2* above 20 ms at baseline. Progressive changes in T2* values were observed at t1 and t2 for all the groups. Ten patients (10/36: 27.8 %) in group A, 3 patients (3/15: 20 %) in group B, 3 patients (3/12: 25%) in group C, respectively, moved from an abnormal T2* (< 20 ms) to normal values, in 32±7 months (Table 1). T2* values at t2 improved significantly compared to baseline (p=0.0006) in patients treated with DFX (group A). In patients treated with combination therapy (DFO and DFP), T2* increased more rapidly in those with severe siderosis (T2* < 10 ms) (p=0.006). No significant changes in left ventricular ejection fraction (LVEF) values were observed in all groups of patients: only patients in group A with baseline cardiac T2* between 10 and 20 ms showed a slight improvement in LVEF (p=0.049). No statistically significant reduction in ferritin levels were associated with ameliorating myocardial T2* values. DISCUSSION AND CONCLUSIONS. Our data showed that compliance to chelation therapy at proper doses significantly improve myocardial T2* over 3-year treatment period. Continued treatment with deferasirox significantly increase myocardial T2* over time, showing its efficacy to remove iron from the heart. DFO and DFP combination therapy seems to ameliorate cardiac T2* more rapidly only in patients with T2* < 10 ms at baseline.Table 1t0t1t2GROUP An.T2*(ms)n.T2*(ms)n.T2*(ms)T2* < 10 ms18.70–0–T2* 10–20 ms1315.3 ± 2.9125.8 ± 2.8415.8 ± 1.9T* > 20 ms2232.3 ± 6.52434.6 ± 6.83233.8 ± 8.0GROUP BT2* < 10 ms48.5 ± 1.137.2 ± 1.70–T2* 10–20 ms414.1 ± 3.8613.5 ± 3.1512.3 ± 1.5T* > 20 ms731.5 ± 7.8632.9 ± 10.01030.4 ± 9.8GROUP CT2* < 10 ms35.9 ± 1.337.9 ± 1.226.9 ± 0.6T2* 10–20 ms513.7 ± 3.0513.4 ± 1.9316.9 ± 3.3T* > 20 ms438.4 ± 17.0438.0 ± 10.7739.8 ± 6.4 Disclosures:No relevant conflicts of interest to declare.

Clinical Application of Cardiac CMR

Obesity is a known risk factor for developing cardiovascular disease, including heart failure. However, the impact of obesity on patients with heart failure is unclear. Weight reduction is a recommended method of prevention of cardiovascular disease. However, the phenomenon of the "obesity paradox" (or "reverse epidemiology") revealed that overweight and mild to moderate obesity are associated with better outcomes in patients with heart failure compared with patients at normal or ideal weight. Even more, increases of weight in cachectic heart failure patients might improve survival, although patients with heart failure who are overweight or mildly to moderately obese have better outcomes than patients with heart failure who are at ideal or normal weight. In heart failure patients, weight reduction through diet regulation, moderate exercise, and bariatric surgery can improve quality of life and New York Heart Association functional class, but it is yet unclear if these measures will improve survival.