Abstract 17388: A Predictive Index of Common Clinical Features is Specific but Not Sensitive for Detecting Transthyretin Cardiac Amyloidosis by 99mTc-pyrophosphate (99mTc-PYP) Scintigraphy in Patients With Severe Aortic Stenosis
Background: Mounting data demonstrate that transthyretin cardiac amyloidosis (ATTR-CA) is a prevalent, underdiagnosed, and important contributor to heart failure with preserved ejection fraction in older adults, especially those with severe aortic stenosis (AS). Multicenter international data have demonstrated that nuclear imaging with bone isotopes can accurately detect ATTR-CA non-invasively without the need for endomyocardial biopsy.
Aim: To investigate whether common clinical variables can accurately predict ATTR-CA detected by nuclear imaging.
Methods: 141 patients with severe AS underwent 99mTc-PYP planar imaging within 30 days of transcatheter aortic valve replacement (TAVR). Myocardial uptake was assessed by both semi-quantitative visual score (range 0: no uptake to 3: uptake greater than bone) and quantitative analysis by drawing a region over the heart, mirroring it to the contralateral chest, and calculating a heart-to-contralateral ratio (HCL). Visual score ≥2 and HCL ≥1.5 were considered positive for ATTR-CA. Demographics, laboratory values, ECG, and echocardiographic data were also analyzed for association with 99mTc-PYP positivity.
Results: Among 141 patients with severe AS (66% men, mean age 84±6 years), 99mTc-PYP uptake was found in 15% (n=21). Of this positive cohort, 90% (n=19) were men, 71% (n=15) had increased interventricular septal size ≥1.2cm, and 52% (n=11) had right bundle branch block (RBBB) on ECG. The triad of male sex, RBBB, and increased septal size (n = 6) was 96% specific for ATTR-CA diagnosed by 99mTc-PYP cardiac imaging, but only 29% sensitive (i.e. missed 16 of 21 positive patients).
Conclusion: Among older males with severe AS, the presence of both RBBB and increased septal size ≥ 1.2cm are specific for diagnosis of ATTR-CA. However, these common clinical variables are poorly-sensitive screening guides, and the cardiologist should not depend on them to refer for 99mTc-PYP imaging.
Author Disclosures: D.L. Narotsky: None. A. Castano: None. R. Morgenstern: None. J. Rubin: None. R. Ehmke: None. S. Bokhari: None. M.S. Maurer: Consultant/Advisory Board; Modest; Dr. Maurer’s institution, Columbia University Medical Center, receives funding for research and serving on advisory boards and DSMBs from Pfizer Inc., Alnylam Pharmaceuticals Inc., ISIS Pharmaceutical.
- © 2016 by American Heart Association, Inc.