John L. Berk, MD: Doctor Desai, I’m coming to you for some advice. I’m about to undergo a TAVR [transcatheter aortic valve replacement]. Do I need to have a technetium pyrophosphate scan? Does it matter whether I have wild-type TTR [transthyretin] if you’re going to do the procedure on me?
Akshay S. Desai, MD, MPH: I think it’s an important consideration for the treating cardiologist to ask the question. I don’t believe that every patient coming for transcatheter aortic valve replacement needs routine evaluation for cardiac amyloid. I think the circumstances in which that should be considered—I think the populations that are not typical are probably populations where we should think about the diagnosis a little more carefully. We have a large proportion of patients who have severe aortic stenosis and a pattern of progression of that disease over time that is really quite typical, and I would be interested in the opinions of Dr Witteles and Dr Hanna. But from my perspective, it wouldn’t make sense or be economically appropriate to sort of test all those people.
The people I would test are the ones we’ve talked about. They’re the patients where the amount of hypertrophy is disproportionate or there are other echocardiographic features that would suggest involvement by an infiltrative disorder like amyloid. I am also particularly interested in these patients with low-gradient aortic stenosis because I think those who have stenosis are a population that might be enriched a bit more for infiltrative heart disorders. But I don’t know. Dr Hanna, any other thoughts there, or Ron?
Mazen Hanna, MD: I agree with Dr Desai. I think that patients with low-flow, low-gradient aortic stenosis have a greater likelihood of having it. The disproportionate degree of hypertrophy—what you’d expect to the degree of the aortic stenosis—I think is a big one. Then the Columbia experience, they looked at the diastolic, the tissue Doppler velocities, which were exceedingly low in the patients who had both aortic stenosis and the cardiac amyloidosis, and I don’t remember what the cut point was. But those are the main things I would look at. Again, I don’t think we can promulgate testing every single person who is coming in for evaluation, but perhaps coming up with some kind of criteria and studying this prospectively would be a good idea.
Ronald Witteles, MD: Yeah. If we think about why the percentage was so high—16% of all-comers in this study—I think none of us believes it’s because TTR amyloid deposits are causing aortic stenosis. It’s because you were picking out an older, predominantly male population with thick hearts and heart failure, and if you do that, you are going to pick up quite a bit of TTR amyloid. I think the points made by doctors Desai and Hanna about the particular clues, like the low-flow, low-gradient aortic stenosis, are very good ones. And I agree, I don’t think we’re quite at the point yet that we can justify universal screening on every patient when referred for TAVR. But I would say it should probably be universally thought of and looking for other signs to make you suspicious for it.