DALLAS – Older patients with carpal tunnel syndrome that requires release surgery appear to have a relatively high prevalence of amyloidosis that, in some, involves their heart, suggesting that routine screening for amyloidosis is warranted in elderly patients undergoing the surgery.
Routine Congo red staining of a tenosynovial biopsy taken at the time of carpal tunnel release surgery in a single-center experience with 96 patients showed that 10 (10%) were positive for amyloidosis,, said at the annual scientific meeting of the Heart Failure Society of America.
Clinicians “should be aware of the association between carpal tunnel syndrome [CTS] and amyloidosis.” When a 60-year old shows up with bilateral CTS without a clear cause, it’s reasonable to suspect amyloidosis, he suggested.
The prospective study run by Dr. Hanna and his associates included men at least 50 years old and women at least 60 years old who underwent CTS release surgery at the Cleveland Clinic during May 2016–June 2017. Enrollment excluded patients with known amyloidosis or rheumatoid arthritis. The patients averaged 68 years of age, 51% were men, and 85% had bilateral CTS that required surgery. The surgeons removed a tenosynovial biopsy at the time of surgery from each of the 96 patients, a “low-risk procedure,” Dr. Hanna said.
The 10 patients with positive staining for amyloid underwent a work-up that included a comprehensive physical examination, a series of blood tests for cardiac biomarkers, an ECG, echocardiography including assessment of cardiac strain, and a technetium-99m pyrophosphate scan. This identified two patients with cardiac involvement. The examinations identified one case by the echocardiographic strain findings and the second case by the technetium pyrophosphate scan. Seven of the 10 patients with amyloid had a history of prior carpal tunnel release surgery.
The researchers also used mass spectroscopy to identify the amyloid type. Seven patients had the transthyretin subtype, including one patient with cardiac involvement; two patients had light chain amyloidosis, including the second patient with cardiac involvement. The tenth patient had inconclusive results but the researchers presumed the amyloid was of the transthyretin type, Dr. Hanna.
The eight patients identified with amyloid but no cardiac involvement at baseline will continue to receive annual work ups to see whether their hearts become affected over time. The protocol delays a repeat technetium pyrophosphate scan until the 4th year following study entry.
The potential usefulness of early identification and treatment of cardiac amyloidosis received support in results from another study reported at the meeting. Researchers from Columbia University Medical Center, New York, and New York Presbyterian Hospital reported their retrospective, nonrandomized experience with 126 patients who had been diagnosed with transthyretin cardiac amyloidosis. Thirty of these patients had received treatment with a transthyretin-stabilizing drug, either the investigational agentor diflunisal, while the other 96 patients received no stabilizing treatment. During a median follow-up of 2 years, patients treated with a stabilizing agent had a statistically significant 68% reduced rate of either death or orthotopic heart transplant, compared with the untreated patients in a multivariate analysis that controlled for various baseline differences between the treated and untreated patients.