Why the Cleveland Clinic Began Screening Carpal Tunnel Patients for Amyloidosis
Cleveland Clinic researchers identified amyloid deposits in 10.2 percent of patients undergoing carpal tunnel release surgery, suggesting biopsies of hand tissue could be an early signal of life-threatening cardiac amyloidosis.
The study, published online in the Journal of American College of Cardiology, contained wide inclusion criteria; all men in their 50s or older and all women in their 60s or older were eligible unless they had known amyloidosis or carpal tunnel syndrome considered to be from trauma or arthritis.
As the authors of an accompanying editorial noted, cardiac amyloidosis is being recognized as a more common form of cardiomyopathy than previously thought, and one that is now treatable given recent innovations. That has changed the attitude surrounding it from “therapeutic nihilism”—“Why diagnose what you can’t treat?”—to a more optimistic approach, according to Matthew S. Maurer, MD, and Frederick L. Ruberg, MD.
“Recent advances have dramatically altered the therapeutic landscape, rendering systemic amyloidosis with cardiac involvement a treatable disease, affording patients an array of therapeutic options,” they wrote. “It is clear that early recognition of amyloidosis is critical because current treatment strategies suppress precursor protein production or stabilize the protein preventing misfolding, but do not directly target existing amyloid deposits.”
Observing that carpal tunnel syndrome often precedes cardiac disease, lead author Brett W. Sperry, MD, and colleagues performed biopsies of tenosynovial tissue taken from 98 patients who underwent the hand surgery.
Upon Congo red staining, amyloid deposits were found in 10.2 percent of the patients, who were 68 years old on average and 51 percent male in the overall cohort. Mass spectrometry in the amyloid patients identified seven of them as having transthyretin amyloidosis (ATTR), two as having light-chain amyloidosis (AL) and one as having an unspecified subtype, although ATTR was suspected.
After sending these patients for further cardiac evaluation, clinicians found two of them already had cardiac amyloidosis, leading to changes in their medications.
“A third patient had a mutation in the TTR gene, which leads to a progressive polyneuropathy, and was also treated with disease-modifying therapy,” Sperry et al. noted. “… These findings point to the importance of recognizing idiopathic carpal tunnel syndrome as a possible predictor for amyloid heart disease, and the opportunity for incorporating tenosynovial tissue biopsy for early detection and diagnosis of amyloidosis in the perioperative workflow.”
The researchers said AL progresses much more rapidly than ATTR once it affects the heart, making it even more important to catch that disease subtype early and initiate proper therapy.
In fact, the results of this study and other emerging evidence around cardiac amyloidosis led to a change in…