062 99Tc-DPD Bone Scintigraphy Correlates With Left Ventricular Wall Thickness and Global Longitudinal Strain in Patients With ATTR Wild Type Cardiac Amyloidosis

Abstract

Cardiac amyloidosis should be considered in patients with cardiomyopathy and unexplained increase in LV wall thickness. ATTR wild type (wt) cardiac amyloidosis is a rare condition characterised by the extracellular deposition of native transthyretin protein. Technetium (99Tc) based bone scintigraphy has revolutionised the investigation and diagnosis of ATTRwt amyloidosis. A single centre retrospective analysis of 96 patients who underwent 99Tc-DPD bone scintigraphy was performed. The cardiac biomarkers and transthoracic echocardiogram performed at the closest date to bone scintigraphy were used for comparison. Measurements of LV wall thickness, longitudinal strain and ejection fraction were collected. Perugini semi-quantitative grading was employed to determine: no (0), limited (1), moderate (2) or intense (3) 99Tc-DPD uptake. All studies were reported by an independent radiologist blinded to patient history and transthoracic echocardiogram findings. In our tertiary referral centre, ninety-six patients have undergone 99Tc-DPD bone scintigraphy for investigation of suspected cardiac amyloidosis. Of these, fifty-four patients (56%) had a positive study. In comparison to transthoracic echocardiography, Perugini grading had a moderate correlation (r=0.48) to interventricular septal wall thickness. There was a weaker correlation (r=0.31) with global longitudinal strain and no correlation with left ventricular ejection fraction. Most ATTRwt patients (83%) undergoing strain assessment had an apical sparing pattern. There was no correlation B-natriuretic peptide or cardiac troponin. In patients with ATTRwt cardiomyopathy, the semi-quantitative 99Tc-DPD bone scintigraphy score correlated with LV wall thickness and global longitudinal strain, but not LV ejection fraction or cardiac biomarkers.