Transcript
Announcer:
This is Heart Matters on ReachMD. Today, we’ll hear from Dr. Sumeet Mitter, Director of Inova Schar Heart and Vascular Research and the Infiltrative and Restrictive Cardiomyopathy Center at Inova Health in Virginia. He’ll be discussing common challenges in diagnosing transthyretin amyloid cardiomyopathy, or ATTR-CM. Here’s Dr. Mitter now.
Dr. Mitter:
One of the things with ATTR cardiomyopathy is making sure that we are absolutely certain about the diagnosis. Up until 2019, the gold standard, and still the gold standard, is a tissue biopsy finding deposited TTR amyloid within the myocardium.
But for that to occur, an individual—and remember, this is an older population—has to go to a cath lab and have a catheter put into their right internal jugular vein and a wire passed through and a biopsy tool to get three microscopic samples for analysis. That can be daunting for an individual, especially an older individual. And sometimes these patients are on blood thinners, so it can pose a challenge.
But we have non-invasive imaging, and there's this whole era of nuclear scintigraphy where as long as we've ruled out light chain amyloidosis, which is from another precursor protein, we can use what's called nuclear scintigraphy, or these bone tracers, to detect the transthyretin amyloid fibers within the myocardium. And these transthyretin cardiac amyloid fibers are very calcium avid. So when I say a bone tracer, our bones harbor calcium, and so these tracers help us look and see the deposit of TTR within the heart. That is predicated on it truly being transthyretin amyloidosis. Sometimes the light chain amyloid fibers are weakly calcium avid, or there's a couple other disease states like end-stage renal disease or really bad coronary artery disease that can also lead to calcification of the myocardium and create a false positive.
So I think one of the most common challenges is to make sure is our nuclear scintigraphy scan, which is kind of the predominant way we're diagnosing most of our patients now, as opposed to using true tissue biopsy, is a truly valid scan. There are false positives and false negatives with any type of test, and we do our best to create a scenario where if we see deposition and it meets the threshold for diagnosis, we truly believe in the validity of the scan and say, "This is transthyretin cardiac amyloidosis."
One of the other common challenges that clinicians may encounter is actually just getting people through a multisystem pathway, making sure they're also getting their neurologic testing done, and then, even once you diagnose, shepherding people through sometimes a complicated pathway for therapeutic access. But luckily, many of the companies have created programs to facilitate that for both the provider and the patient.
Announcer:
That was Dr. Sumeet Mitter discussing how we can address challenges in diagnosing ATTR-CM. To access this and other episodes in our series, visit Heart Matters on ReachMD.com, where you can Be Part of the Knowledge. Thanks for listening!
