ACC: Early recognition, diagnosis of cardiac amyloidosis critical
A new expert consensus decision pathway published by the American College of Cardiology highlights the importance of recognizing and diagnosing cardiac amyloidosis at an early stage to allow the most favorable outcome.
The document, published in the Journal of the American College of Cardiology, includes a diagnostic algorithm that outlines the role of the monoclonal protein screen, bone scintigraphy and/or genetic testing and/or biopsy.
Data were derived from Kittleson MM, et al. J Am Coll Cardiol. 2023;doi:10.1016/j.jacc.2022.11.022.
“Clinical recognition and diagnosis of cardiac amyloidosis at an early stage of the disease is critical, affording an affected patient the widest array of treatment options that have a favorable impact on survival and/or prevent potentially irreversible loss of physical function and quality of life,” Michelle M. Kittleson, MD, PhD, director of postgraduate medical education in heart failure and transplantation at Cedars-Sinai Heart Institute and chair of the writing committee, and colleagues wrote. “Several recent critical advances in the diagnostic approach, coupled with approval of effective therapies and widespread engagement by societies, regulatory bodies and advocacy organizations, have elevated cardiac amyloidosis to a position of diagnostic prominence.”
Pitfalls in delay of diagnosis
Cardiac amyloidosis is a restrictive cardiomyopathy, most commonly due to misfolded amyloid monoclonal immunoglobulin light chains (AL) from an abnormal clonal proliferation of plasma cells or amyloid transthyretin (ATTR), a liver-synthesized transport protein.
Most patients with ATTR cardiomyopathy (ATTR-CM) do not receive a timely diagnosis. The authors noted that many patients see more than five physicians before receiving a correct diagnosis because of perceived disease rarity, overlap with other more “common” diseases, and the seemingly disconnected constellation of clinical findings, which can include musculoskeletal, neurologic, gastrointestinal and renal manifestations.
“Even if cardiac amyloidosis is suspected, pitfalls in the diagnostic algorithm may result in misdiagnosis, with potentially catastrophic consequences given the marked differences in treatment approaches and prognoses for untreated AL-CM vs. ATTR-CM,” the researchers wrote.
The document focuses on the need for a multidisciplinary approach to individual care. Additionally, specialized cardiac expertise may also be warranted regarding HF management; the indications for and contraindications to advanced HF therapies, such as heart transplantation and mechanical circulatory support; and the role of palliative care.
Three steps for multidisciplinary care
The multidisciplinary care of amyloidosis involves three steps, according to the researchers. The first step is identifying what general cardiologists should know about the diagnosis and management of cardiac amyloidosis and what decisions require consultation with a cardiac amyloid specialist.
The second step is recognizing the relevant extracardiac manifestations and when to establish multidisciplinary collaboration. The third step is to understand barriers to equitable care, future directions and unanswered questions.
The cardiac amyloidosis diagnostic algorithm should always begin with a monoclonal protein screen to assess for the presence of a plasma cell disorder and, therefore, supportive evidence for AL-CM, the researchers wrote. Cardiac scintigraphy has emerged as a cornerstone of noninvasive ATTR-CM diagnosis; however, cardiac uptake that is consistent with ATTR-CM (grade 2 or 3 uptake) may be present in more than 10% of patients with AL-CM, according to the decision pathway.
“Cardiac manifestations alone are insufficient to conclusively distinguish AL from ATTR amyloidosis because there is considerable overlap of clinical, imaging, and electrocardiographic features,” the researchers wrote. “There are some pathognomonic extracardiac manifestations of AL amyloidosis, including macroglossia/submandibular gland enlargement from soft tissue involvement and periorbital purpura from capillary fragility and acquired factor X deficiency. In contrast, musculoskeletal manifestations, such as spontaneous biceps tendon rupture and spinal stenosis, are unique to ATTR amyloidosis.”
The document also includes steps to implement a treatment plan with specific attention to the roles of traditional HF medications and arrhythmia management.
‘Index of suspicion’ needed
The researchers noted that CV specialists must incorporate the appropriate “index of suspicion,” accurate diagnostic algorithms, timely identification of multisystem involvement with appropriate multidisciplinary collaboration, and disease management strategies to optimize outcomes in patients with amyloidosis.
“Not only is cardiac amyloidosis more common than previously thought and the subtleties of diagnosis important to recognize, but the multisystem manifestations require attention and appropriate referral to skilled subspecialists,” the researchers wrote. “For example, although the noninvasive diagnosis of ATTR cardiac amyloidosis appears potentially straightforward, there are diagnostic pitfalls enumerated herein that may result in misdiagnosis, with catastrophic consequences for the patient.”
The document was endorsed by the American Association of Neuromuscular & Electrodiagnostic Medicine, the Heart Failure Society of America and the International Society of Amyloidosis.
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