Background/Purpose:

Rheumatoid arthritis (RA) is one of the major causes of amyloid A (AA) amyloidosis, the major organs affected being the kidneys and gastrointestinal (GI) tract. Although cardiac amyloidosis is the principal cause of death in patients with amyloid L (AL) amyloidosis, significant cardiac involvement in AA amyloidosis is thought to be rare. On the other hand, the survival rate of hemodialysis patients with AA amyloidosis associated with RA has been shown to be low, and our previous study revealed that cardiac failure accounted for more than half of the mortality in these patients. Here we attempted to clarify the nature of cardiac involvement in patients with RA-associated AA amyloidosis and its clinical significance.

Methods:

Forty-seven RA patients (7 males, 40 females) with AA amyloidosis who were followed up at our hospital and Niigata University Hospital between 2001 and 2014 were enrolled. All of the patients fulfilled the 2010 ACR/EULAR classification criteria for RA, had undergone biposy of the GI tract (n=41), myocardium (n=2), kidney (n=2), or abdominal fat (n=2), and had been confirmed to have reactive AA amyloidosis by histopathological examination. The patients’ background data and echocardiographic features were analyzed retrospectively. Data indicated are median values [range].

Results:

The median age of the 47 patients was 68 [48-89] years, the mean period between RA onset and echocardiographic examination was 25 [2-43] years, and the mean period between the onset of AA amyloidosis and echocardiographic examination was 1723 [0-7682] days. Echocardiography showed that the median left ventricular (LV) posterior wall thickness was 10.9 [6.0-16.6] mm, with an interventricular septal thickness of 11.0 [5.5-17.0] mm, and an ejection fraction (EF) of 70.0% [32.3-85.4%]. Twenty-seven patients with a LV wall thickness of >11.0 mm were assigned to a LV hypertrophy (LVH+) group, and their clinical features were compared to the remainder (LVH- group; n=20). The Mann-Whitney U test demonstrated no significant differences between the LVH+ and LVH- groups at the baseline in terms of patient age (68 [48-89] years vs. 68 [50-86] years; p=0.829), duration of RA (27[4-41] years vs. 23[2-43] years; p=0.59), and DAS28(3)-CRP (2.73[1.15-5.36] vs. 3.23 [1.42-6.87]; p=0.09). Patients in the LVH+ group had a higher systolic blood pressure (137.4 [116-170] vs. 128.1 [116-170] mmHg in the normal group, p=0.024), a lower echocardiogram EF (68.1% [32.3-85.0%] vs 72.5% [59.6-79.3%]; p=0.03), and a lower estimated glomerular filtration rate (eGFR) (38.7 [13.0-98.8] ml/min/1.73 m² vs. 62.8 [19.2-126.4] ml/min/1.73 m²; p=0.003). Fatalities in the LVH group (n=27) vs. normal group (n=20) were 13 vs. 1 at three years. Log rank test revealed that an older age (>65 years; p=0.073), lower eGFR (<40 ml/min/1.73 m²; p=0.027), and LVH+ (p=0.002) were associated with higher mortality at 3 years after echocardiography. The Cox hazard regression model indicated LVH+ as an independent risk factor (hazard ratio = 12.4; 95% CI 1.62 – 94.8; p = 0.016).

Conclusion:

Thickening of the LV wall is a notable cardiac feature of patients with AA amyloidosis and is strongly suspected to contribute to a poor prognosis.

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ACR Meeting Abstracts - https://acrabstracts.org/abstract/cardiac-involvement-in-patients-with-amyloid-a-amyloidosis-due-to-rheumatoid-arthritis/