Cardiac Amyloidosis: A Potentially Underdiagnosed Cause of Heart Failure

Core Concepts

Cardiac amyloidosis, though considered rare, may be more prevalent than commonly thought and should be considered in the differential diagnosis for patients presenting with heart failure, especially those with unusual responses to standard treatments.

Abstract

The content discusses the importance of considering cardiac amyloidosis as a potential cause of heart failure, particularly in patients with heart failure with preserved ejection fraction (HFpEF). Key points include:

Amyloidosis may be more common than previously thought, with one case series finding evidence of amyloidosis in 1 in 8 patients undergoing aortic valve replacement for aortic stenosis.
When echocardiography shows increased ventricular wall thickness, it is important to distinguish between true hypertrophy and an infiltrative process like amyloidosis. The content recommends using the term "increased wall thickness" rather than "hypertrophy" when the underlying cause is unclear.
Red flags that should raise suspicion for cardiac amyloidosis include new-onset bilateral carpal tunnel syndrome, biceps tendon rupture, trigger finger, macroglossia, periorbital purpura, easy bruising, and foamy urine (proteinuria).
For suspected AL amyloidosis, testing for serum and urine protein electrophoresis and free light chains is recommended, as a positive result would warrant urgent referral to hematology.
For suspected ATTR amyloidosis, technetium pyrophosphate (Tc-PYP) scintigraphy can provide a non-invasive diagnosis, avoiding the need for tissue biopsy in some cases.
Patients with cardiac amyloidosis are very sensitive to volume shifts and vasodilation, so standard heart failure medications like diuretics and vasodilators need to be used cautiously to avoid worsening symptoms.

Stats

One case series found evidence of amyloidosis in 1 in 8 patients who underwent aortic valve replacement for aortic stenosis.

Quotes

"Every article says it's a rare diagnosis. But Dr Kittleson told us that in one case series, 1 in 8 patients who went through aortic valve replacement for aortic stenosis had evidence of amyloidosis. It's probably considered rare because we haven't always diagnosed it."
"If the echo shows increased ventricular wall thickness and one of these other red flags, then you should consider amyloidosis. It's easier to diagnose than you might think once you look for it."

Key Insights Distilled From

When Heart Failure Is Actually Cardiac Amyloidosis

by Matthew F. W... at www.medscape.com 06-27-2024

https://www.medscape.com/viewarticle/when-heart-failure-actually-cardiac-amyloidosis-2024a1000blr

Deeper Inquiries

What factors may contribute to the potential underdiagnosis of cardiac amyloidosis in the past?

One major factor contributing to the potential underdiagnosis of cardiac amyloidosis in the past is the misconception that it is a rare condition. Despite being labeled as rare in medical literature, studies have shown that the prevalence of amyloidosis may be higher than previously thought. Additionally, the lack of specific symptoms or the presence of non-specific symptoms in patients with cardiac amyloidosis can lead to misdiagnosis or delayed diagnosis. The overlap of clinical features with other more common conditions, such as heart failure, can also contribute to underdiagnosis. Furthermore, the need for specialized tests and expertise in diagnosing amyloidosis may have limited its recognition in routine clinical practice.

How can clinicians be encouraged to have a higher index of suspicion for cardiac amyloidosis in patients presenting with heart failure?

Clinicians can be encouraged to have a higher index of suspicion for cardiac amyloidosis in patients presenting with heart failure by increasing awareness about the prevalence of the condition and its varied clinical presentations. Education and training programs focusing on the key clinical features and diagnostic modalities of cardiac amyloidosis can help clinicians recognize the red flags that should prompt further investigation. Utilizing specific terminology, such as "LV thickness increase" instead of "LV hypertrophy," can also aid in prompting clinicians to consider amyloidosis in the differential diagnosis. Additionally, highlighting the importance of early diagnosis and the potential impact on treatment outcomes can motivate clinicians to maintain a high level of suspicion for cardiac amyloidosis in patients with heart failure.

What other emerging diagnostic or treatment modalities for cardiac amyloidosis are on the horizon that could improve outcomes for these patients?

Several emerging diagnostic and treatment modalities for cardiac amyloidosis are on the horizon that could potentially improve outcomes for patients. In terms of diagnostics, novel imaging techniques, such as cardiac magnetic resonance imaging (MRI) and positron emission tomography (PET) scans, are being explored for their ability to detect amyloid deposits in the heart with greater sensitivity and specificity. These advanced imaging modalities can provide valuable information for early diagnosis and monitoring of disease progression. On the treatment front, ongoing research is focusing on the development of targeted therapies that aim to disrupt the formation of amyloid fibrils or enhance their clearance from the body. Gene-silencing therapies and monoclonal antibodies are among the promising approaches that hold potential for improving outcomes in patients with cardiac amyloidosis. Additionally, advancements in supportive care strategies, such as tailored management of volume status and symptom control, are also expected to contribute to better outcomes and quality of life for patients with cardiac amyloidosis.