Incremental Values of T1 Mapping in the Prediction of Sudden Cardiac Death Risk in Hypertrophic Cardiomyopathy: A Comparison With Two Guidelines

Abstract

Background: MRI native T1 mapping and extracellular volume fraction (ECV) are quantitative values that could reflect various myocardial tissue characterization. The role of these parameters in predicting the risk of sudden cardiac death (SCD) in hypertrophic cardiomyopathy (HCM) is still poorly understood.Aim: This study aims to investigate the ability of native T1 mapping and ECV values to predict major adverse cardiovascular events (MACE) in HCM, and its incremental values over the 2014 European Society of Cardiology (ESC) and enhanced American College of Cardiology/American Heart Association (ACC/AHA) guidelines.Methods: Between July 2016 and October 2020, HCM patients and healthy individuals with sex and age matched who underwent cardiac MRI were prospectively enrolled. The native T1 and ECV parameters were measured. The SCD risk was evaluated by the 2014 ESC guidelines and enhanced ACC/AHA guidelines. MACE included cardiac death, transplantation, heart failure admission, and implantable cardioverter-defibrillator implantation.Results: A total of 203 HCM patients (54.2 ± 14.9 years) and 101 healthy individuals (53.2 ± 14.7 years) were evaluated. During a median follow-up of 15 months, 25 patients (12.3%) had MACE. In multivariate Cox regression analysis, global native T1 mapping (hazard ratio (HR): 1.446; 95% confidence interval (CI): 1.195–1.749; P < 0.001) and non-sustained ventricular tachycardia (NSVT) (HR: 4.949; 95% CI, 2.033–12.047; P < 0.001) were independently associated with MACE. Ten of 86 patients (11.6%) with low SCD risk assessed by the two guidelines had MACE. In this subgroup of patients, multivariate Cox regression analysis showed that global native T1 mapping was independently associated with MACE (HR: 1.532; 95% CI: 1.221–1.922; P < 0.001). In 85 patients with conflicting results assessed by the two guidelines, end-stage systolic dysfunction was independently associated with MACE (HR: 7.942, 95% CI: 1.322–47.707, P = 0.023). In 32 patients with high SCD risk assessed by the two guidelines, NSVT was independently associated with MACE (HR: 9.779, 95% CI: 1.953–48.964, P = 0.006).Conclusion: The global native T1 mapping could provide incremental values and serve as potential supplements to the current guidelines in the prediction of MACE.

Myocardial Extracellular Volume Fraction Measured by Cardiac Magnetic Resonance Imaging Negatively Correlates With Cardiomyocyte Breadth in a Healthy Porcine Model

“…Cardiac ECV is a quantitative value that could reflect various myocardial tissue characterization, especially myocardial fibrosis ( 24 – 34 ). Histological verification of the ECV in reflecting collagen deposition; however, has only been reported by a small number of qualified centers, and most later studies have followed their data and used the ECV as a direct indicator of myocardial fibrosis ( 6 , 26 ).…”

“…Previous studies by our research team have shown that the variations of ECV detected by cardiac MRI in healthy individuals follow certain rules, which indicates that the ECV and cardiomyocytes are intrinsically linked ( 20 ). In the early stage of hypertension, the ECV decreased rather than increased during the adaptive growth process of the heart, suggesting that although myocardial fibrosis elevates the ECV, cardiac hypertrophy can also lead to a decrease in the ECV ( 24 ). This finding prompted us to propose a hypothesis that the size of cardiomyocytes may be one cause of the physiological changes of ECV.…”

Avaliação e estratificação da cardiomiopatia hipertrófica quanto ao risco de morte súbita: uma revisão integrativa

“…Através de diferenciação dos tempos de relaxamento dos tecidos que compõem o miocárdio, pode-se mensurar o grau de fibrose intersticial, muitas dessas áreas não identificáveis ou de difícil delimitação pela técnica de realce tardio, assim como, de posse do valor do hematócrito, traduzir essa informação em percentagem de volume extracelular, através de fórmula específica [14] . Estudos recentes trazem o mapeamento T1 como uma ferramenta promissora, tanto na diferenciação de CMH com outras cardiomiopatias, como na avaliação prognóstica desses pacientes [15,16,17] . VO2 do limiar anaeróbico, parecem ser mais indicados [18] .…”

Multimodality Cardiac Imaging in Cardiomyopathies: From Diagnosis to Prognosis

“…Further, T1 and T2 mapping are useful in the differential diagnosis of left ventricular hypertrophy [21]. Small studies have so far reported prognostic implications of T1 mapping [22] and ECV [23] values. However, further studies are needed to validate the prognostic implications of mapping sequences to fully incorporate them into daily clinical practice.…”