Sirolimus is associated with impaired hematopoiesis in heart transplant patients? A retrospective analysis

Proliferation signal inhibitors may adversely impact bone marrow function. We sought to describe the impact of sirolimus on hemoglobin and erythropoiesis in heart transplant recipients.

We have conducted a single-center, retrospective analysis of all heart transplant patients treated with sirolimus. We measured serum hemoglobin (Hb) at baseline and at 3 months to determine the prevalence of anemia and change in Hb after sirolimus initiation. We also characterized hematologic profile of patients to gain insights into the effects of sirolimus on erythropoiesis.

There were 84 patients included in the study. The prevalence of anemia increased from 71% to 75% after sirolimus initiation. Anemic patients were more likely to be male (P = .026) and have worse renal function (glomerular filtration rate 49 ± 27 vs 70 ± 42 mL/min; P = .012). A ≥20 g/L drop in Hb was observed in 25% of the overall cohort. Patients investigated for anemia (n = 67) had a low Hb (111 ± 24 g/L), normal mean corpuscular volume (87 ± 47 FL), and low serum iron levels (10 ± 5 μmol/L) and transferrin saturation (0.22 ± 0.12). Serum ferritin was variable (263 ± 370 μg/L). Bone marrow evaluation in 19 patients revealed adequate marrow iron stores in all cases.

Anemia is prevalent in heart transplant patients treated with sirolimus and increases over time. Patients have a characteristic hematologic profile suggestive of anemia of chronic disease and functional iron deficiency.