Post-transplant erythrocytosis after kidney transplantation: A review.

Post-transplant erythrocytosis (PTE) is defined as persistently elevated hemoglobin > 17 g/dL or hematocrit levels > 51% following kidney transplantation, independent of duration. It is a relatively common complication within 8 months to 24 months post-transplantation, occurring in 8%-15% of kidney transplant recipients. Established PTE risk factors include male gender, normal hemoglobin/hematocrit pre-transplant (suggestive of robust native kidney erythropoietin production), renal artery stenosis, patients with a well-functioning graft, and dialysis before transplantation. Many factors play a role in the development of PTE, however, underlying endogenous erythropoietin secretion pre-and post-transplant is significant. Other contributory factors include the renin-angiotensin- aldosterone system, insulin-like growth factors, endogenous androgens, and local renal hypoxia. Most patients with PTE experience mild symptoms like malaise, headache, fatigue, and dizziness. While prior investigations showed an increased risk of thromboembolic events, more recent evidence tells a different story-that PTE perhaps has lessened risk of thromboembolic events or negative graft outcomes than previously thought. In the evaluation of PTE, it is important to exclude other causes of erythrocytosis including malignancy before treatment. Angiotensin converting enzyme inhibitors (ACE-I) and angiotensin receptor blockers (ARBs) are the mainstays of treatment. Increased ACE-I/ARB use has likely contributed to the falling incidence of erythrocytosis. In this review article, we summarize the current literature in the field of post-transplant erythrocytosis after kidney transplantation.