NT-proBNP Levels at Diagnosis: A Key Indicator of Disease Severity in Transthyretin Cardiac Amyloidosis

Researchers at the Cleveland Clinic in Florida presented their findings on the clinical relevance of NT-proBNP levels at the time of diagnosis in transthyretin cardiac amyloidosis (ATTR-CA) at the 2024 International Symposium on Amyloidosis. This study, conducted by Malcolm Lawson McDonald and colleagues, underscores the importance of NT-proBNP as a biomarker in stratifying disease severity and guiding early management strategies.

ATTR-CA is a complex disease characterized by the deposition of misfolded transthyretin proteins in the heart, leading to progressive heart failure. Predicting disease progression and severity is crucial for implementing early and effective treatment. This study aimed to stratify patients with ATTR-CA based on their NT-proBNP levels at diagnosis and examine the differences in their clinical characteristics.

The study retrospectively analyzed 192 patients with confirmed ATTR-CA, diagnosed between February 2016 and December 2022. Patients were categorized into quartiles based on their NT-proBNP levels at diagnosis. Data on demographics, comorbidities, and medications were collected and compared across the quartiles.

The study cohort had a mean age of 78.3 years, with 90.6% being male. The median NT-proBNP level was 1884.5 pg/mL, with an interquartile range (IQR) of 817.5-3737.3 pg/mL. Key findings include:

• Age and Comorbidities: Patients in higher NT-proBNP quartiles tended to be older, although this was not statistically significant (P=.2). Comorbidity profiles were similar across quartiles, except for a higher prevalence of atrial fibrillation in the higher quartiles (P<.001).
• Functional Classification: Higher NT-proBNP quartiles were associated with worse New York Heart Association functional classification (P<.001), indicating more severe heart failure symptoms.
• Renal Function and LVEF: Patients with higher NT-proBNP levels had significantly lower glomerular filtration rates (GFR; P<.001) and more impaired left ventricular ejection fraction (LVEF), reflecting advanced cardiac dysfunction.

The study highlights NT-proBNP as a crucial biomarker for assessing disease severity in ATTR-CA at the time of diagnosis. Patients with higher NT-proBNP levels exhibit more severe symptoms, worse renal function, and greater cardiac impairment. These findings emphasize the need for aggressive and multidisciplinary management approaches in patients presenting with elevated NT-proBNP levels to improve outcomes.