Myocardial structural and functional changes in cardiac amyloidosis - insights from a prospective observational patient registry

Abstract

Abstract Background Within the last decade, cardiac amyloidosis (CA) has been acknowledged as a significant cause of heart failure and patients who are affected face a dismal prognosis, especially in later stages of the disease. The pathophysiological hallmark of cardiac amyloidosis (CA) is the deposition of amyloid within the myocardium. Consequently, extracellular volume (ECV) of affected patients increases. However, studies on ECV progression over time and its' impact on prognosis are lacking. Objectives We aimed to investigate the progression of ECV and its prognostic impact in CA patients. Methods Serial cardiac magnetic resonance (CMR) examinations, including ECV quantification were performed in consecutive CA patients. Results Between 2012 and 2021, 103 CA patients underwent baseline and follow-up CMR, including ECV quantification. Median ECVs at baseline of the total (n = 103), transthyretin [(ATTR) n = 80], and [light chain (AL) n = 23] CA cohorts were 48.0%, 49.0%, and 42.6%. During a median follow-up period of 12 months, ECV increased significantly in all cohorts (48.0% to 50.5%, p<0.001; 49.0% to 50.5%, p<0.001; 42.6% to 50.6%, p = 0.026). Separate analyses for treatment-naïve (n = 14) and treated (n = 66) ATTR patients revealed that the median change of ECV from baseline to follow-up was significantly higher among untreated patients (5.5% versus 2.7%, p = 0.035). Survival analyses demonstrated that median change of ECV was an independent (adjusted for troponin t and NT-proBNP) predictor of outcome in all CA cohorts [total: hazard ratio (HR): 1.114, 95% confidence-interval (CI): 1.045 – 1.189, p<0.001; ATTR: HR: 1.099, 95% CI: 1.014 – 1.192, p = 0.022; AL: HR: 1.142, 95% CI: 1.006 – 1.297, p = 0.040]. Conclusions The present study demonstrates that ECV, quantified by CMR T1 mapping, increases significantly in CA patients over the course of 12 months. While ECV increased, irrespective of amyloid type our analyses showed the highest increase among untreated ATTR patients. Moreover, the change of ECV was an independent predictor of adverse outcomes in AL, as well as ATTR patients emphasizing the usefulness of CMR T1 mapping in the management of CA patients.Figure 1.Dot PlotsFigure 2.Kaplan Meier Curves