Associazione Nazionale Medici Cardiologi Ospedalieri



Role of endomyocardial biopsy in asymptomatic carriers of Transthyretin mutation: a case report.

Costantino Jacopo Roma(Roma) – Universit√† degli studi di Roma “La Sapienza”, Policlinico Umberto I | Ballatore Federico Roma(Roma) – Universit√† degli studi di Roma “La Sapienza”, Policlinico Umberto I | Marchionni Giulia Roma(Roma) – Universit√† degli studi di Roma “La Sapienza”, Policlinico Umberto I

Introduction: There are two forms of cardiac amyloidosis (ATTR-CM) from Transthyretin, one wild-type (ATTRwt) and one hereditary (ATTRv), with autosomal dominant transmission. The introduction of new specific therapies has made it possible to block the progression of the disease. The success of these therapies is mainly linked to the early treatment. For this reason, early diagnosis represents a fundamental objective.

Case Report: A 56-year-old man came to our attention due to a mutation of pathogenetic significance in the gene coding for TTR (Ile68Leu). The genetic test was performed following the diagnosis of ATTRv in a first-degree relative (brother aged 58, with onset of symptoms at around 55 years). In medical history he reported a history of bilateral carpal tunnel confirmed by electroneurography and trigger finger. Blood tests showed normal levels of NT-proBNP and TroponinThs (74 pg/mL and 0.005 mcg/L). The ECG showed RS at 60 bpm with normal AV and IV conduction, normal voltages and no changes in ventricular repolarization. The echocardiogram and MRI showed no signs suggestive of amyloidosis. The scintigraphy with bone tracers did not highlight partological hyperfixation in the heart (Perugini score 0). In consideration of the similar age of onset of the disease in the affected brother (predicted time of disease onset, PADO) and the presence of carpal tunnel, which typically precedes the onset of cardiac amyloidosis by a few years, after informed consent, the patient underwent endomyocardial biopsy. Unexpectedly, histological and immunohistochemical analysis revealed the presence of initial transthyretin amyloid deposits. The patient underwent therapy with Tafamidis and after two years of follow-up he did not show disease progression.

Conclusions: The experience of this case underlines how the most used methods for the evaluation of ATTRv carriers do not always allow an effective evaluation of cardiac involvement, now widely recognized as the prognostic factor with the greatest impact on survival. In carriers reaching PADO age, endomyocardial biopsy could be considered an option for identifying subclinical cardiac involvement by starting therapy early and improving quality of life and the prospect of long-term survival.