Factors Affecting Coronary Flow in Children

Factors Affecting Coronary Flow in Children Elhadi H. Aburawi, MD, MSc, FRCPI, FRCPCH Division of Paediatric Cardiology, Department of Paediatrics, Lund University, Sweden Abstract Background: A number of inborn and exogenous factors influence the flow and function of the coronary arteries with possible consequences on the cardiovascular risk. The regulation of the coronary flow is partly dependent on the functional integrity of coronary endothelial cells, coronary perfusion pressure, and myocardial function. Objectives: To investigate the effects of some of the previously suggested cardiovascular risk factors on coronary flow and function in children. Methods: Blood lipid pattern and concentration of acute phase proteins and their relation to prior infections were studied. The effect of preceding airway infections on the endothelium-dependent vasomotor function of the brachial artery in healthy and type 1 diabetes mellitus children was assessed. Coronary flow was measured with transthoracic Doppler echocardiography before and after non-surgical and surgical treatment of congenital heart defects. Results: Pro-atherogenic changes consisting of decreased circulating levels of high density lipoprotein and albumin were observed in children with past infections. The brachial artery's endothelial vasomotor function was impaired in children with type 1 diabetes, being further affected by preceding mild infections in the upper airways. Compared to controls, coronary flow was increased in patients with left-to-right shunt and coarctation of aorta, and increased further after open heart surgery. In contrast, coronary flow decreased, even if not to normal, after coarctectomy and device closure of atrial septal defect. Cardiac output decreased after open heart surgery but improved after device closure. The coronary flow velocity and velocity time integral decreased with increasing CRP after open heart surgery in particular in those with prolonged aortic cross clamping. Conclusions: Residual pro-atherogenic disturbances in vascular endothelial function, lipid and albumin metabolism may be observed in children with past infections, especially in those with chronic cardiovascular risk factors such as diabetes mellitus. Cardiac malformations and open heart surgery affect negatively the coronary blood flow and cardiac output. LIST OF PUBLICATIONS This thesis is based on the following papers, which will be referred to by the Arabic numerals: 1. Aburawi EH, Grubb A, Raitakari O, Viikari J, Pesonen E. Lowered levels of serum albumin and HDL-cholesterol in children with a recent mild infection. Annals of Medicine. 2006;38:154-160. 2. Aburawi EH, Liuba P, Pesonen E, Yla-Herttuala S, Sjoblad S. Acute respiratory viral infections aggravate arterial endothelial dysfunction in children with type 1 diabetes. Diabetes Care. 2004;27:2733-5. 3. Aburawi EH, Berg A, Liuba P, Pesonen E. Effects of cardio-pulmonary bypass surgery on coronary flow in children assessed with transthoracic Doppler echocardiography. Am J Physiol Heart Circ physiol. 2007 May 4, (Epub ahead of print) 4. Aburawi EH, Berg A, Pesonen E. Coronary blood flow in patients with atrial septal defect before and after surgical versus device closure A transthoracic Doppler echocardiography study. (Submitted to Circulation). 5. Aburawi EH, Liuba P, Berg A, Pesonen E. C-reactive protein and coronary microcirculation in children after open heart surgery A transtoracic Doppler echocardiography study. Cardiology in the Young (in press).