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

ObjectiveTo describe the prevalence of and risk factors for renal infarction (RI) in patients with cardiac amyloidosis.Patients and MethodsWe 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.ResultsThree 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).ConclusionOur 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.