Myocardial determinants of Functional limitation in advanced Fabry cardiomyopathy

Abstract Background Cardiac involvement in Fabry Disease (FD) manifests as left ventricular hypertrophy (LVH) often complicated by myocardial fibrosis and/or inflammation. Both LVH and advanced tissue alterations can be non-invasively detected and quantified by cardiac magnetic resonance (CMR) with Late Gadolinium Enhancement (LGE). Impairment in functional capacity has been previously reported in FD patients. However, there is limited data regarding the determinants of myocardial alterations in exercise intolerance in FD. Methods Among 190 consecutive FD patients referred for CMR, 41 simultaneously performed a cardiopulmonary exercise test (CPET) to evaluate functional capacity. All patients underwent an extensive CMR protocol to provide a detailed evaluation of cardiac morphology and function, including multiparametric tissue characterization. CPET parameters were compared between patients with advanced Fabry cardiomyopathy (Group B), characterized by hypertrophy, inflammation, and fibrosis, and FD patients without irreversible cardiac damage (Group A). Results Group B patients were older compared to Group A (57.0 years vs 33.5 years, p<0.001), had a greater LVH (LVMI: 117 g/sqm vs 76.5 g/sqm, p<0.001; LVMWT 17 vs 10 mm, p<0.001). LV ejection fraction was preserved in both groups but Group B patients had a lower peak VO2 value compared to group A (17.8 ml/kg/min vs 21.9 ml/kg/min, p=0.025), a lower (but not significant) percent-predicted peak VO2. A negative linear correlation was identified between the LGE extension (expressed as % of LV mass) and peak VO2 (r=-0.553, p=0.014). This correlation remained consistent even after excluding patients under chronic beta-blocker therapy (r=-0.678, p=0.045). No significant correlation between LV mass and peak VO2 was found. Conclusions in patients with FD, the presence of advanced tissue alterations detected by LGE is associated with reduced functional capacity (low peak VO2) despite preserved LV ejection fraction, with a significant negative correlation.