Renal Infarction and Its Consequences for Renal Function in Patients With Cardiac Amyloidosis

Abstract

Objective: To describe the prevalence of and risk factors for renal infarction (RI) in patients with cardiac amyloidosis.

Patients and methods: We evaluated 87 patients with cardiac amyloidosis who underwent renal technetium-99m-labeled dimercaptosuccinic acid scintigraphy in the Amyloidosis Referral Center of Henri-Mondor Hospital from October 1, 2015, through February 28, 2018.

Results: Three groups of patients were identified according to the underlying amyloidosis disorder: AL amyloidosis in 24 patients, mutated-transthyretin amyloidosis in 24 patients, and wild-type transthyretin amyloidosis in 39 patients. Patients with wild-type transthyretin amyloidosis were older (P<.001), more likely to be men (P=.02), to have arrhythmic heart diseases (P<.001), and to be receiving anticoagulation treatment (P<.001). Patients with AL amyloidosis had significantly higher N-terminal pro-B-type natriuretic peptide levels (P=.02) and were more likely to have nephrotic syndrome (P<.001). Renal infarction was detected in 18 patients (20.7%), at similar frequencies in the various groups. Baseline urinary protein to creatinine ratio was the only parameter for which a significant difference (P=.03) was found between patients with and without RI diagnoses. The likelihood of RI diagnosis was 47.1% (8 of 17) in the presence of AKI and 14.5% (10 of 69) in its absence (P=.003). Overall, heart transplant-censored patient survival did not differ significantly between patients with and without RI (P=.64), but death- and heart transplant-censored renal survival was significantly lower in patients with RI (P<.001).

Conclusion: Our study suggests that prevalence of RI in patients with cardiac amyloidosis is higher than previously thought, regardless of the underlying amyloidosis disorder. Acute kidney injury in a patient with cardiac amyloidosis should alert clinicians to the possibility of RI.