In the Journal of Yeungnam Medical Science, researchers presented the case of a heart transplant recipient identified as having a rare pathogenic variant of hereditary transthyretin amyloidosis (hATTR).
A 65-year-old woman was referred for cardiac screening and genetic testing due to cardiomegaly on chest radiography and a family history of unknown heart disease. Her brother, however, was recently diagnosed with hATTR.
A 24-hour ambulatory electrocardiogram revealed multiple premature ventricular beats. Transthoracic echocardiography demonstrated reduced longitudinal strain with an apical sparing pattern; it also revealed a left ventricular ejection fraction of 29% and wall thickness of 14 mm, as well as diastolic dysfunction. Blood investigations revealed raised N-terminal pro-B-type natriuretic peptide (NT-proBNP) levels of 3,055 pg/mL and high-sensitivity troponin I levels of 0.219 ng/mL. Coronary angiography showed normal coronary arteries.
The patient also had symptoms of numbness in the dorsa of her feet. She experienced dizziness when standing up. Investigations included nerve conduction studies, which revealed sensory abnormalities in the lower extremities that involved the sural nerve; a table tilt test confirmed orthostatic hypotension.
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Technetium scintigraphy revealed biventricular amyloid deposition; a cardiac biopsy found amyloid fibril accumulations in the myocardium. Genetic testing demonstrated a rare transthyretin pathogenic variant that was confirmed in her brother. These investigations were sufficient for a diagnosis of hATTR to be made.
Optimal medical therapy was commenced. However, her NT-proBNP levels and right ventricular systolic pressure continued to rise. Her physicians considered her to be a suitable candidate for heart transplantation, which was performed upon receiving an organ donation from a deceased donor.
Six months after surgery, a cardiac biopsy revealed no amyloid deposits or signs of transplant rejection. The patient is currently well and is on tafamidis and immunosuppressants. She no longer has neurological symptoms.
“This case report emphasizes the importance of genetic testing for hATTR, particularly in families with a history of neurological symptoms or heart failure,” the authors concluded.
Reference
Kim MS, Lee SY, Kim KH. A rare pathogenic variant identified in a heart transplant recipient with hereditary transthyretin amyloidosis: a case report. J Yeungnam Med Sci. Published online May 30, 2023. doi:10.12701/jyms.2023.00241
