Phlebotomy in cyanotic congenital heart disease with hyperviscosity syndrome

Phlebotomy is often resorted to in patients with cyanotic congenital heart disease (CCHD) and symptoms of hyperviscosity (hyperviscosity syndrome) due polycythemia which occurs in response to hypoxia which causes an increased erythropoietin level. In contrast, increased erythropoiesis in polycythemia rubra vera occurs with normal or low erythropoietin levels. Hemoglobin levels and hematocrit are important considerations while planning venesection in those with symptoms of hyperviscosity. Hyperviscosity syndrome is characterized by impaired tissue oxygen delivery with symptoms like headache, visual disturbances, loss of concentration, paresthesia, muscle weakness, and fatigue. It should be remembered that dehydration and iron deficiency may precipitate hyperviscosity symptoms and just hydration may relieve symptoms in some cases [Rose SS et al. Cyanotic Congenital Heart Disease (CCHD) with Symptomatic Erythrocytosis. J Gen Intern Med. 2007; 22: 1775–1777]. Venesection in turn can lead to iron deficiency which can form a vicious cycle by increasing symptoms of hyperviscosity as the microcytes of iron deficiency (identified by lower mean corpuscular volume or MCV) are less deformable and can clog the microcirculation. This can also enhance the risk of stroke instead of reducing the risk. Hydroxyurea has been tried for reducing erythrocytosis in some refractory cases, though it has the risk of producing transient marrow suppression which responds to dose reduction [Reiss UM et...
Source: Cardiophile MD - Category: Cardiology Authors: Tags: General Cardiology Source Type: blogs