A comparative analysis of clinical, laboratory, imaging, and pathological characteristics of various variants of amyloid cardiomyopathy based on local registry data
Abstract
Aim . To characterize the phenotypic characteristics and diagnostic principles of various variants of amyloid cardiomyopathy based on local registry data. Material and methods . From 2017 to 2025, 195 patients with suspected cardiac amyloidosis were examined. The diagnosis was verified in 103 patients. Transthyretin (ATTR) amyloidosis was diagnosed in 63 patients (61,2%), and light-chain (AL) amyloidosis — in 40 patients (38,8%). Most patients with ATTR amyloidosis (79%) were diagnosed using a noninvasive algorithm, including bone scintigraphy with radiopharmaceutical and hematological tests to rule out AL amyloidosis. Results . Patients with wild-type ATTR (ATTRwt) were older and had a higher prevalence of hypertension, while patients with AL amyloidosis were younger. Class III-IV heart failure was more common in the ATTRwt and AL groups compared to ATTRv amyloidosis (41%, 53%, and 21%, respectively, p<0,05). The highest prevalence of arrhythmias was observed in patients with ATTRwt as follows: atrial fibrillation occurred in 83% of patients; episodes of ventricular tachycardia — in 41%. Peripheral nervous system involvement was more prevalent in the ATTRv group (85%) compared to ATTRwt (38%) and AL (28%) amyloidosis (p=0,0001). Compared with the ATTRwt and ATTRv groups, proteinuria was more common in patients with AL amyloidosis (14%, 24%, and 68%, p<0,0001). According to scintigraphy data, Perugini grade 2/3 technetium pyrophosphate accumulation was observed in 61 patients (100% of those examined) with ATTR amyloidosis and 5 (26% of those examined) with AL amyloidosis. Three patients with ATTR amyloidosis had paraprotein in the serum or urine, necessitating morphological verification of the diagnosis. Heart failure therapy primarily consists of mineralocorticoid receptor antagonists and loop diuretics, as well as low-dose beta-blockers. Renin-angiotensin system blockers were prescribed in low doses and were received by less than 30% of patients in both groups. Conclusion . Despite the high prevalence of AL amyloidosis, transthyretin amyloidosis appears to be the predominant cause of cardiology consultations. The high mortality rate associated with AL amyloidosis cannot be ruled out as an influence on registry studies of various types of amyloidosis. A noninvasive algorithm, including bone scan and hematological tests, has proven high diagnostic value in verifying the diagnosis of ATTR amyloidosis. However, if laboratory testing reveals abnormalities, morphological verification of the diagnosis is indicated. Given the restrictive physiology, standard therapy for heart failure in amyloid cardiomyopathy requires significant modification.