Echocardiography and Survival in Light Chain Cardiac Amyloidosis: Back to Basics

Amyloids and the Heart: An Update

Amyloids consist of fibrils that can be formed by a large variety of different precursor proteins. In localized amyloidosis, amyloids accumulate at the production site with a single organ being affected, whereas in systemic amyloidosis several organs are affected, with the heart being the most common, followed by the kidneys, liver, and the nervous system. The two most frequent systemic amyloidosis types affecting the heart in the vast majority (>95%) of cases are immunoglobulin light chain (AL) amyloidosis and transthyretin (TTR) amyloidosis (ATTR amyloidosis). Patients with amyloid cardiopathy (CA) often present with non-specific heart failure symptoms as well as other clinical manifestations depending on the organ or systems involved. However, there are some findings associated with amyloidosis called "red flags" (clinical, echocardiographic, magnetic resonance imaging), which may assist in guiding the physician to the correct diagnosis. The present state-of-the-art review summarizes the features of the various cardiac phenotypic expressions of amyloidosis, proposes a simplified pathway for its diagnosis, and highlights the rapidly evolving therapeutic landscape.

Detection and Diagnosis of Cardiac Amyloidosis in Egypt

Cardiac amyloidosis is a life-threatening disease that occurs when amyloid proteins, most commonly immunoglobulin light chain or transthyretin, mutate or become unstable, misfold, deposit as amyloid fibrils, and accumulate in the myocardium. Early diagnosis of cardiac amyloidosis is hindered by insufficient awareness, specifically regarding clinical red flags and diagnostic pathways. Cardiac amyloidosis diagnosis comprises two important phases, clinical suspicion (phase one) followed by definitive diagnosis (phase two). Each phase is associated with specific clinical techniques. For example, clinical features, electrocardiography, echocardiography, and cardiac magnetic resonance imaging serve to raise suspicion of cardiac amyloidosis and facilitate early diagnosis, whereas laboratory tests (i.e., blood or urine electrophoresis with immunofixation), biopsy, scintigraphy-based nuclear imaging, and genetic testing provide a definitive diagnosis of cardiac amyloidosis. In Egypt, both the lack of cardiac amyloidosis awareness amongst healthcare providers and the unavailability of clinical expertise for the use of diagnostic techniques must be overcome to improve the prognosis of cardiac amyloidosis in the region. Previously published diagnostic algorithms for cardiac amyloidosis have amalgamated techniques that can raise clinical suspicions of cardiac amyloidosis with those that definitively diagnose cardiac amyloidosis. Though such algorithms have been successful in developed countries, diagnostic tools like echocardiography, scintigraphy, and cardiac magnetic resonance imaging are not ubiquitously available across Egyptian facilities. This review presents the current state of knowledge regarding cardiac amyloidosis in Egypt and outlines a new diagnostic algorithm which leverages regional nuclear imaging expertise. Importantly, the proposed diagnostic algorithm guides accurate amyloid-typing to mitigate misdiagnosis and erroneous treatment selection and improve the cardiac amyloidosis diagnostic accuracy in Egypt.

Independent prognostic value of left ventricular mass index in patients with light-chain amyloidosis

BACKGROUND

Echocardiographic-determined left ventricular mass index (LVMI) provides quantitative information on left-ventricular structure. However, its prognostic value on light-chain (AL) amyloidosis has not been clearly defined.

METHODS

We included 99 patients with newly diagnosed AL amyloidosis between July 2013 and March 2022. Clinical features and echocardiographic parameters were collected.

RESULTS

LVMI ≥113.4 g/m² was predictive for overall survival (OS) and progression-free survival (PFS) with respective hazard ratios (HRs) of 2.87 (95% CI: 1.04-7.79) and 2.91 (95% CI: 1.25-6.68). Patients in the LVMI-high group had higher NT-proBNP, cTnT, and FLC-diff levels. They were more likely to be cardiac involved and have increased mean left ventricular wall thickness, decreased left ventricular ejection fraction, and higher proportion of patients with pericardial effusion. In subgroup analysis, LVMI-high group was associated with a reduced OS [HR: 4.74 (95% CI: 1.26-17.77)] and PFS [HR: 7.16 (95% CI: 2.10-24.40)] in patients with cardiac amyloidosis (CA). Besides, LVMI-high was associated with a reduced OS [HR: 3.58 (95% CI: 1.17-11.02)] and PFS [HR: 4.79 (95% CI: 1.77-12.94), p = 0.00] among patients staged of II or III (Mayo 2004), as well as reduced OS [HR: 22.65 (95% CI: 1.66-299.31)] and PFS [HR: 18.73 (95% CI: 2.36-148.35)] among patients staged of III or IV (Mayo 2012).

CONCLUSIONS

LVMI is a reliable prognostic indicator of survival. A cut-off of LVMI (113.4 g/m²) was prognostic for OS and PFS. Importantly, LVMI was able to identify a subset of patients with poorer prognosis in the context of CA or in the late stages according to the biomarker staging systems.

Cardiac Amyloidosis: Current Diagnostic Strategies Using Multimodality Imaging

Amyloidosis is a systemic disorder in which abnormal amyloid proteins deposit in body organs, leading to organ dysfunction and death. Cardiac amyloid deposition, causing a sort of restrictive cardiomyopathy and associated with increased risk of mortality. Most cases of cardiac amyloidosis are of either light chain or transthyretin type. Early and accurate diagnosis of cardiac amyloidosis may improve outcomes. However, diagnosis requires systematic approach including electrocardiography and biomarkers when encountered suspicious candidate. Diagnosis by multimodality noninvasive imaging have been substantially studied and established for differentiation from subtypes. Recent advance in the treatment of amyloidosis offers therapeutic monitoring and prognosis.