22 Sep Ruptured Biceps Tendon and Wild-type Transthyretin Amyloidosis
MedicalResearch.com Interview with:
Dr. Singh
Avinainder Singh, M.B.B.S.
Research Fellow
Cardiovascular Medicine
Brigham & Women’s Hospital
Harvard Medical School
Boston, MA
MedicalResearch.com: What is the background for this study?
Response: Amyloidosis due to aberrant folding of proteins. These misfolded proteins can deposit in various parts of the body and lead to organ dysfunction. The two most common types of amyloidosis affecting the heart include transthyretin and light chain amyloidosis. Transthyretin is a protein produced by the liver which supports the transport of thyroxine and retinol.
Wild-type transthyretin amyloidosis (ATTRwt, previously known as senile amyloidosis) occurs due to deposition of misfolded fibrils derived from transthyretin and primarily affects elderly men. Once considered a rare disease, it is now reported to be responsible for nearly 13% of heart failure with preserved ejected fraction and increased wall thickness.
Rupture of the biceps tendon is a rare occurrence in the general population (<1 per 1000). We noticed a ruptured biceps tendon in several patients with wild-type transthyretin amyloidosis and performed this study to further evaluate this finding in a group of patients with wild-type transthyretin amyloidosis and in a control group of age-matched patients with non-amyloid heart failure.
MedicalResearch.com: What are the main findings?
Response: A ruptured biceps tendon was present in 37/111 (33.3%) of patients with wild-type transthyretin amyloidosis. When present, it was noted in the dominant arm of 95% of patients, and occurred several years prior to onset of heart failure. It was only present in 1/40 (2.5%) patients with non-amyloid heart failure.
If we consider the 13% prevalence of ATTRwt in HFpEF to be accurate, the presence of a ruptured biceps tendon in an individual with HF would have a positive predictive value of 66% for this diagnosis.
MedicalResearch.com: What should readers take away from your report?
Response: Rupture of the biceps tendon, an uncommon finding in the general population was observed in 1/3 of patients with wild-type transthyretin amyloidosis. This clinical sign can be easily elicited by flexing the forearm against resistance and observing for a bunching up of the muscle belly. Its presence in an elderly individual with heart failure., increased left ventricular wall thickness and a normal or near-normal ejection fraction should raise suspicion for amyloidosis as an underlying etiology. This diagnosis can easily be determined by technetium pyrophosphate cardiac imaging.
MedicalResearch.com: What recommendations do you have for future research as a result of this study?
Response: Early detection of wild-type transthyretin amyloidosis has the potential to modify disease course, as several agents are under investigation which can slow disease progression, or potentially remove amyloid deposits.
This novel clinical sign can provide a diagnostic clue to the etiology of heart failure and will aid in diagnosis as well as serve to increase awareness of wild-type transthyretin amyloidosis. This was a single-center study, and findings should be replicated by other centers.
Disclosures: Dr. Falk has received fees for consulting from Ionis and Alnylam Pharmaceuticals and funding from GlakoSmithKline.
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Last Updated on September 22, 2017 by Marie Benz MD FAAD