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Clinical significance of histopathologic patterns of cardiac amyloidosis
Insights
Morphologic markers differentiate primary (AL) and senile cardiac amyloidosis (SCA). Clinically significant cardiac amyloidosis involves grade 2+ myocardial deposits and vascular arteriole changes.
Area of Science:
- Cardiovascular Pathology
- Medical Diagnostics
Background:
- Cardiac amyloidosis is a significant cause of heart failure and arrhythmias.
- Distinguishing between primary (AL) and senile cardiac amyloidosis (SCA) is crucial for prognosis and management.
- Morphologic features can indicate the clinical significance of amyloid deposition in the heart.
Purpose of the Study:
- To identify distinct morphologic markers differentiating primary (AL) and senile cardiac amyloidosis (SCA).
- To correlate specific amyloid deposition patterns and extents with clinical significance in cardiac amyloidosis.
Main Methods:
- Histological analysis of 47 autopsy-proven cardiac amyloidosis cases (21 AL, 26 SCA).
- Grading amyloid deposition extent (1-4) and classifying patterns (nodular, perifiber, mixed).
- Assessment of vascular involvement, specifically intramyocardial arterioles.
Main Results:
- Primary amyloidosis (AL) hearts showed high-grade deposits (76% grades 3-4), perifiber/mixed patterns, and frequent vascular involvement (90%).
- Senile cardiac amyloidosis (SCA) hearts exhibited low-grade deposits (62% grades 1-2), predominantly nodular patterns (92%), and infrequent vascular involvement (4%).
- Clinically significant disease correlated with grade 2+ myocardial deposits and intramyocardial arteriole involvement.
Conclusions:
- Distinct histological patterns and extents of amyloid deposition characterize AL and SCA.
- Vascular involvement, particularly of intramyocardial arterioles, is a key marker of clinically significant cardiac amyloidosis.
- Morphologic assessment aids in understanding the progression and severity of cardiac amyloidosis.
Abstract:
Cardiac amyloidosis may be asymptomatic or an important cause of progressive heart failure and refractory arrhythmia. To identify the morphologic markers of clinically significant cardiac amyloidosis, we analyzed the hearts of 47 patients with autopsy-proven cardiac amyloidosis (21 with primary amyloidosis [AL] and 26 with senile cardiac amyloidosis [SCA]) histologically for the extent and pattern of amyloid deposits. The extent of amyloid deposition was graded 1 through 4, corresponding with less than 10%, 10 to 25%, 26 to 50%, and more than 50% histologic involvement of the myocardium, respectively. The pattern of deposits was classified as nodular, perifiber, or mixed type, and the presence or absence of vascular involvement was determined. The hearts with primary amyloidosis showed predominantly high-grade deposits (76% grades 3 and 4), a perifiber (65%) or mixed (30%) pattern of deposits, and frequent (90%) vascular involvement. The hearts with senile cardiac amyloidosis tended to have low-grade deposits (62% grades 1 and 2), a nodular pattern (92%) of deposits, and infrequent (4%) vascular involvement. Clinically significant cardiac amyloidosis was associated with grade 2 or greater amyloid deposits in the heart and with involvement of intramyocardial arterioles.