PREDICTORS OF PLATELETS COUNT IN PEDIATRIC PATIENTS WITH CONGENITAL CYANOTIC HEART DISEASE

Abstract

C ongenital heart defects are the most common developmental anomaly and are the commonest non-infectious causes of mortality in newborns in the western world. Erythrocytosis, thrombocytopenia, platelets function defects, coagulation factors deficiencies are the main haematologic disorders in patients with cyanotic congenital heart disease. We aimed to assess the reticulated platelet count in pediatric patients with congenital heart disease and thrombocytopenia compared to non thrombocytopenic, detecting the risk factors that may predispose patients with congenital heart disease to low platelet count and identify possible pathogenetic mechanisms responsible for thrombocytopenia in CCHD. The present study included 60 pediatric patients with congenital cyanotic heart diseases attending at pre-catheter visit at Ain-Shams University, Cardiology Department between October 2012 and July 2013, we completed laboratory data for 46 patients of them. Patients were subjected to comprehensive history taking including data for Age, gender, type of congenital cyanotic heart disease, age of onset of cyanosis, cyanotic episodes and their frequencies, drugs and family history. Physical examination included anthropometric measures, oxygen saturation by pulse-oximetry and Vital signs. Laboratory investigation included complete blood count (CBC) using Coulter Counter GEN-S (Coulter Corporation, USA), differential leucocyte counts were performed manually on Leishman stained blood smear, C-reactive protein (CRP) by latex agglutination test using spectrum kits latex (Fortress, England), reticulated platelet count as a marker of platelet production using Sysmex XE-2100 (Sysmex, Japan), Prothrombin Time (PT, Pro Time) test, Partial thromboplastin time (PTT) and D-dimer for patients with thrombocytopenia The study included 30 (65.2%) males and 16 (34.8%) females, the youngest age was 1 month and the eldest was 192 months, with a median of 18.5 months and interquartile range of 51 months. Nine patients had transposition of great arteries, 30 patients had tetralogy of Fallot, 6 patients had double outlet right ventricle and one of them had single ventricle There was no significant difference between patients with thrombocytopenia and patients with normal platelet count as regard demographic data or clinical presentation, type of congenital cyanotic heart disease or C-reactive protein status. Immature platelets fraction (IPF) was higher in patients with thrombocytopenia 14.15±5.2 compared to non-thrombocytopenic 6.68±3.39 (P=0.003), and PT was longer (17.08±3.37, 13.99±1.41 sec, P= 0.01 respectively) with no difference in PTT between both groups (P=0.272). A significant positive correlation was found between platelets count with D-Dimer and a significant negative correlation with PT and IPF. A significant positive correlation was also found between IPF and hemoglobin, RBC count, Hematocrit, PT and reticulocytic count, and a significant negative correlation between IPF and MCHC, D Dimer, platelets count, reticulocyte hemoglobin content and platelets large fraction. Patients with different types of CCHD had no significant difference as regard platelets count. There was significant higher RDW and D Dimer in patients with TOF. There was significant higher mean platelets volume and PT in patients with CRP +ve compared to those with CRP-ve. We concluded that patients with CCHD are liable to thrombocytopenia which constituted 13% of the studied patients; immature platelets fraction as a marker for platelets production together with D-dimer were elevated in patients with thrombocytopenia suggesting peripheral platelets destruction as underlying mechanism. RBC count, hemoglobin level, hematocrit and reticulocyte hemoglobin content as a marker for iron deficiency were not a significant determinants for platelets count.