الفهرس 
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Abstract
Patent ductus arteriosus (PDA) is the most common cardiovascular abnormality in preterm neonates, occurring in about 33% of infants less than 30 weeks gestation and in up to 60% of infants less than 28 weeks gestation. Left to right shunting across the PDA is associated with congestive heart failure, increased ventilatory dependence, pulmonary or intraventricular hemorrhages (Van and Chemtobs, 2005).
Respiratory distress syndrome (RDS) involves about 50% of neonates with gestational age less than 30 weeks. A part from the immature myocardium and the shunting across the fetal channels of the PDA, cardiac functions was influenced by the severity of respiratory distress and its ventilator management (Trivisanuto et al., 2000).
Echocardiography remains the gold standard for diagnosis using PDA (Elkhuffash et al., 2008). Myocardial ischemia and its effect on cardiac function can be assessed by ECG, echocardiography, assay of biochemical markers and autopsy.
Troponin t (cTnT) and troponin I can be found within the myocardial filaments. measuring these cardiac troponin levels in full term and preterm infants has not become a common practice in the neonatal intensive care unit. Researcher studies are discovering that an elevation in cTnT levels can be directly correlated in with the severity of illness and can be potentially prognostic of morbidity (Ottinger and David, 2013).
Our aim of this study was to correlate cTnt level with clinical and echocardiographic markers of PDA significance initially or early after delivery, and to assess cTnT level after successful PDA closure. We focused particularly on determining the correlation of cTnT level and multiple variables such as sex or gender, gestational age, weight of neonate, delivery mode, Apgar score at one and five minutes, the presence of maternal complication, oxygen therapy, mechanical ventilation and surfactants use, use of intropics, diuretics or brufen and indomethacin and outcome or mortality.
This case control study was conducted in Al Demerdash Neonatal Intensive Care Unit between April 2013-April 2014. We classified infants as patients group: 41 VLBW (birth weight ≤ 1.5kg) with clinically significant PDA manifested with presence of heart murmur, tachycardia, hyperactive, precordium and increase in amplitude pulse at the upper left parasternal border. Ductal diameter > 1.6 mm was considered significant and control group: 36 VLBW without clinically significant PDA. We excluded preterms neonates with congenital malformations isolated or multiple, genetic syndromes or severe asphyxia and persistent pulmonary hypertension.
All our patients were subjected to detailed obstetric, perinatal, and postnatal history, maternal history of complication especially hypertension, mode of delivery, Apgar score at one and five minutes, intake of medications as inotropic agents, diuretics, brufen or indomethacin. Thorough clinical examination including chest, cardiac, abdominal and neurological examinations. Assessment of vital signs and signs of cardiac decompensation like congestive heart failure, tachycardia, tachypnea, cardiomegaly, hepatomegaly, up to gallop rhythm. Recording the type of feeding whether enteral or parenteral, feeding intolerance. Manifestations of RDS, need for surfactant or oxygen up to mechanical ventilation.
Investigations were done including CBC, CRP, cTnT concentration assay by ELISA twice initially on the second day of life and follow up on the fifth to seventh day.
Echocardiographic studies were done initially and follow up by the end of the first week were performed using standard neonatal windows including apical, parasternal, subcostal and high parasternal windows. Two dimensional, M mode imaging were recorded. The following echocardiographic findings were determined in each study: Ductal diameter: absolute diameter in millimeter from high parasternal view (ductal diameter > 1.6mm was considered significant), Left ventricular end systolic diameter (mm), Left ventricular end diastolic diameters (mm), Fraction shortening (%), Ejection fraction (%), Inter ventricular septal diameter (mm), Right ventricular diameter (mm), Trivial mitral valve regurgitation, Aortic valve regurgitation, Tricuspid valve regurgitation, and Pulmonary stenosis.
In our study para one mothers, multiple pregnancy and normal vaginal deliveries were more frequent in patients group than in control group. The weight of the newborns were significantly less in patients than in control group.
There is significant decrease in Apgar score at 1 and 5 minutes between patients and control group, negative correlation between cTnT concentration and Apgar score at 1 and 5 minutes initially.
There is highly statistically significant increase in the use of the mechanical ventilation, surfactant in patients than control group.
There is statistically significant decrease in hemoglobin level in patients than in control group initially, while no difference as regard total leucocytic count platelet count or CRP. Negative correlation between the troponin t concentration and hemoglobin level in the control group by the end of 1st week.
Infants of patients group had significantly higher median cTnT levels (0.31±0.06 ng/dl) than those in control group (0.16±0.03ng/dl) initially. There were statistically significant difference between the patient and control group in some echocardiographic findings such as LVESD, right ventricular diameter, EF, mild mitral and tricuspid regurgitation and pulmonary stenosis. Our study revealed no significant correlation between LVESD, LVEDD and troponin level early in the first two days in patients and control group.
Moreover, ejection fraction and fraction shortening were improved in patients group than in control group by the end of the first week. Improvement of LVEDD, pulmonary stenosis, right ventricular hypertrophy and tricuspid regurgitation in patients than in control group occurred by the end of the first week.
Our study reported that the troponin concentration have significant positive correlation with the increase in the size of patent ductus arteriosus initially in the first two days of life, then significantly decreased with the closure of the PDA.
Sex, gestational age and weight were comparable in patients and control group, there was no significant difference in cTnT concentration.
Eleven patients having congestive heart failure. All of them were using inotropic agents, brufen or indomethacin but only 6 receiving diuretics. The patients group showed significant increase in the frequency of using inotropics and prostaglandin antagonists than in control group. There was statistically significant increase in troponin concentration in patients having congestive heart failure in the first few days of life. Our result found that significant positive correlation between the cTnT and use of intropics and the larger size of PDA.
Finally, in the present study cTnT in conjunction with echocardiography may provide the basis for early diagnosis and detection of complication of VLBW infants with hemodynamically significant PDA for trials of targeted medical treatment.