Echocardiographic evolution of patients undergoing 99mTc-DPD scintigraphy for suspected cardiac amyloidosis

Abstract Introduction Cardiac transthyretin amyloidosis (ATTR) is usually associated with thickening of the interventricular septum (IVS), although this finding is not specific and can be attributed to other diseases such as high blood pressure (HBP) or hypertrophic cardiomyopathy. The objective was to evaluate echocardiographic changes over time in patients with ventricular hypertrophy, undergoing 99mTc-DPD scintigraphy (DPD), in order to compare findings between patients with cardiac amyloidosis and other etiologies. Methods Retrospective registry of 63 patients who underwent DPD due to suspected cardiac amyloidosis in our center between 2018 and 2021. Clinical and echocardiographic characteristics were collected, including 2 echocardiograms per patient, with a minimum separation of one year (echo1, echo2). We compared patients diagnosed with ATTR, with positive scintigraphy grade 2–3 (ATTR group), with patients with negative scintigraphy (grade 0, nATTR group). Results The mean age of the patients was 81.3±8.6 years, 67.7% males. 83.9% of patients had HBP, without differences between groups (table1). DPD was positive in 32 (51.6%) patients. Patients with a negative DPD were diagnosed with hypertensive heart disease. The median time between echo1 and echo2 was 3.5 years (IQR 1.2–7), with no differences between groups (4.9 years in nATTR group vs 3.8 years in ATTR group, p=0.2). Results are shown in table1. In echo1, no significant differences were observed in the IVS and biventricular function between both groups. However, in echo3, patients in the ATTR group had significantly greater interventricular septum (IVS) thickness and a worse biventricular function compared to the nATTR group. A significantly greater growth of the IVS and deterioration of left ventricular ejection fraction (LVEF) between echo1 and echo2 was observed in the ATTR group (table1). The percentage of IVS increase respect to the basal value was also significantly higher in ATTR group. There were no significant differences in the IVS growth per year. In the multivariable analysis LVEF and IVS thickness were independent predictors of a positive DPD. Conclusions The increase in thickness of the IVS and deterioration of left ventricular ejection fraction during follow-up of patients with ventricular hypertrophy could be a differential characteristic of ATTR, compared to patients with ventricular hypertrophy of other etiologies. This echocardiographic findings could help to suspect the presence of ATTR. Funding Acknowledgement Type of funding sources: None.