Idiopathic carpal tunnel syndrome as an early clinical indicator of transthyretin cardiac amyloidosis: diagnostic insights
R Machado, P Palma, H Moreira, L Vieira, M Fonseca, A Martins, S Pimenta, J Quelhas-Santos, E MartinsAbstract
Background
Carpal tunnel syndrome (CTS) has emerged as an early clinical manifestation of transthyretin-associated cardiac amyloidosis (ATTR-CA). With recent advances in disease-modifying therapies for ATTR-CA, early detection is critical for improving patient outcomes. Bone tracer cardiac scintigraphy offers a precise and sensitive method for diagnosing ATTR-CA and may serve as a valuable screening tool.
Purpose
To investigate the relationship between idiopathic CTS and ATTR-CA and evaluate the diagnostic and therapeutic implications of screening for ATTR-CA in this population.
Methods
Patients with idiopathic CTS underwent clinical evaluation, and cardiovascular imaging, including bone scintigraphy with 99mTc-DPD, echocardiography, and cardiovascular magnetic resonance (CMR). Continuous variables are reported as median (range) and categorical variables as counts and percentages.
Results
Forty-eight patients were included, with a median age of 76 (50-99) years, and 21 (43.8%) were male. Scintigraphy revealed Perugini grade 2 or 3 uptake in 11 patients (22.9%), diagnosing ATTR-CA. The ATTR-CA cohort had a median age of 81 (75-99) years and was predominantly male (81.8%). The median time from CTS symptom onset to ATTR-CA diagnosis was 6 (0-16) years. Six ATTR-CA patients (54.5%) had a cardiovascular history, primarily heart failure. At diagnosis, echocardiography showed left ventricular hypertrophy (LVH) in 9 ATTR-CA patients (81.8%), with a median interventricular septum (IVS) thickness of 15 (11-21) mm. Seven patients underwent CMR, all of whom showed late gadolinium enhancement (LGE), mostly intramyocardial. Follow-up echocardiography (n=7) demonstrated disease progression in 5 patients (71.4%), showing a median LV ejection fraction decrease of 8% (-20 to -2) and an IVS increase of 3 mm (1-16). Additionally, one scintigraphy-negative patient was diagnosed with amyloid light-chain CA, presenting with biventricular hypertrophy on echocardiography and intramyocardial/subendocardial LGE on CMR.
Conclusions
In patients with idiopathic CTS, screening uncovers early-stage amyloidosis, particularly ATTRwt. The significant 6-year diagnostic delay and evidence of structural disease progression support the integration of targeted screening to enable timely diagnosis and treatment.