Abstract 13456: Screening for Transthyretin Cardiac Amyloidosis Using 99mTc-Pyrophosphate Scintigraphy in Patients Undergoing Transcatheter Aortic Valve Replacement
Background: Transthyretin cardiac amyloidosis (ATTR-CA) is an increasingly recognized cause of heart failure with preserved ejection fraction (EF). Bone scintigraphy has emerged as a non-invasive imaging approach that is highly sensitive and specific for identifying ATTR-CA. We conducted a prospective cohort study using 99mTc-pyrophosphate scintigraphy (99mTc-PYP) to determine the prevalence of ATTR-CA and other clinical associations with 99mTc-PYP positivity in older patients with severe aortic stenosis (AS) undergoing transcatheter aortic valve replacement (TAVR).
Methods: A total of 40 patients (53% men) with severe AS underwent 99mTc-PYP planar cardiac imaging within 30 days of TAVR. Myocardial uptake was assessed with both a semi-quantitative visual score (range 0: no uptake to 3: uptake greater than bone) and by quantitative analysis by drawing a region of interest over the heart, mirroring it to the contralateral chest, and calculating a heart-to-contralateral ratio (HCL). Semi-quantitative score ≥ 2 and HCL ≥ 1.5 were considered positive for ATTR-CA. Demographics and pre-TAVR clinical history, laboratory values, EKG, and echocardiographic data were also analyzed for association with 99mTc-PYP positivity.
Results: Among 40 patients (mean age 85.2+5.3 years), 99mTc-PYP uptake was found in 10% (n=4), all men. Mean semi-quantitative score was 2.8±0.5 and HCL was 1.6±0.1. Elevated BNP (1379±689 vs 438±483 pg/ml, p=0.02), decreased serum albumin (3.2±0.5 vs 3.8±0.5 g/dL, p=0.02), and both larger interventricular septal wall (1.3±0.4 vs 1.0±0.2 cm, p=0.01) and left posterior wall thickness (1.3±0.6 vs 0.9±0.2 cm, p=0.04) at diastole were associated with 99mTc-PYP positivity. There was no difference in EF, but myocardial contraction fraction, the ratio of stroke volume to myocardial volume, was significantly lower, 24±12% vs 45±18%, in 99mTc-PYP positive patients (p=0.03).
Conclusions: 99mTc-PYP has potential as a screening tool for ATTR-CA in high-risk populations. Our data suggest that ATTR-CA may be prevalent in patients undergoing TAVR, particularly men, 20% of whom had a positive 99mTc-PYP scan. Identifying specific etiologies of heart failure in TAVR patients may be important for prognostication and response to therapy.
- Cardiac imaging
- Noninvasive cardiac imaging
- Radionuclide imaging
- Transcatheter aortic valve implantations
Author Disclosures: D.L. Narotsky: Other Research Support; Modest; Dr Maurer received funds to conduct research on TTR Amyloid from Alnylam Pharmaceuticals, FoldRx Inc., and Pfizer, Inc.. Consultant/Advisory Board; Modest; Dr Maurer serves on an advisory board, Transthyretin Amyloid Outcomes Survey. S.K. Kodali: None. M.S. Mauer: Other Research Support; Modest; Received funding to conduct research in TTR amyloid by Alnylam Pharmaceuticals, FoldRx Inc., and Pfizer, Inc.. Consultant/Advisory Board; Modest; Advisory Board of the Transthyretin Amyloid Outcomes Survey, funded by Pfizer, Inc.. S. Bokhari: None. N. Hamid: None. T. Pozniakoff: None. R. Weinberg: None. T.M. Nazif: None. I. George: None. T. Vahl: None. R.T. Hahn: None. A. Castano: None.
- © 2015 by American Heart Association, Inc.