Background: Patients with V30M-TTR familiar amyloid polyneuropathy (FAP) may develop cardiomyopathy, which usually manifests with diastolic dysfunction and parietal thickening. Only a minority of these patients develops clinical manifestations, namely heart failure. Thus, the evaluation of cardiac infiltration is relevant because it constitutes an index of the stage of systemic amyloid infiltration, which can be serially determined.
Purpose: To characterize the evolution of the longitudinal myocardial deformation (LMD) in the spectrum of V30M-TTR FAP progression, in order to determine the usefulness of this parameter as a marker of cardiac infiltration.
Methods: Single-center prospective study of consecutive V30M-TTR mutation carriers. All patients underwent clinical evaluation with neurological involvement assessment. A transthoracic echocardiogram was performed and post-processing speckle-tracking analysis was performed from the apical 4, 3 and 2-chamber chambers, by the same operator blinded to clinical data. The LMD parameters were compared according to symptomatic status and duration of the symptomatic disease.
Results: A total of 186 patients were studied (51.1% of female gender, mean age=46±13 years). About 67% (N=125) had symptomatic disease for 4 years [interquartile range (IQ):2–7] and the remaining 33% (N=61) were asymptomatic carriers. All patients had normal left ventricular ejection fraction (65%, IQ: 12%). A significant reduction of global LMD was observed in symptomatic patients (-17±4 vs -19±3%, P<0.001) and with the increase of symptoms duration (-18±3% at 3 years, -17±4% at 3–6 years, -16±4% after 6 years of symptoms, P=0.015). Regarding the topographic distribution, symptomatic patients had a decrease of LMD at the basal (-16±6 vs -18±6%, P<0.001) and middle (-17±5 vs -19±5%, P<0.001) segments while the apical segments were speared (-20±7 vs -21±6%, P=NS).
Conclusion: Progression of FAP is accompanied by subclinical changes in systolic function, manifested by compromise of longitudinal myocardial deformation. A peculiar pattern was identified, with predominant involvement of the mid-basal segments and apical sparing.