Key echocardiographic elements of coarctation of the aorta in infants

ЧА Қ АЛО Қ ЛАРДА АОРТА КОАРКТАЦИЯСИНИНГ АСОСИЙ ЭХОКАРДИОГРАФИК ЭЛЕМЕНТЛАРИ

Эхокардиография - аорта коарктацияси (АКо)нинг айниқса 6 ойгача бўлган болаларда қўлланиладиган асосий диагностика усулларидан бири ҳисобланади. Баъзи ҳолларда чегараланган эхо-паттерн ёки катта очиқ артериал йўл мавжудлиги туфайли аорта коарктациясини аниқлаш қийин бўлади.   Тадқиқотимиз мақсади чақалоқларда аорта коарктациясининг асосий эхокардиографик кўрсаткичларини излашдан иборат эди.

Калит сўзлар: аорта коарктацияси, эхокардиография,  чақалоқлар,  компьютер томография, аорта ёйи.

Introduction. Coarctation of the aorta       the arteries branch off to take blood to the head is a birth defect in which a part of the aorta is        and arms, near the patent ductus arteriosus, although narrower than usual. If the narrowing is severe       sometimes the narrowing occurs before or after enough and if it is not diagnosed, the baby may       the ductus arteriosus. In some babies with have serious problems and may need surgery or       coarctation, it is thought that some tissue from other procedures soon after birth. For this       the wall of ductus arteriosus blends into the reason, coarctation of the aorta  is often       tissue of the aorta. When the tissue tightens and considered a critical congenital heart defect. The       allows the ductus arteriosus to close normally defect occurs when a baby’s aorta does not form       after birth, this extra tissue may also tighten and correctly as the baby grows and develops during       narrow the aorta. It is estimated that pregnancy. The narrowing of the aorta usually      approximately 60% to 80% of newborns with happens in the part of the blood vessel just after       aortic coarctation are not diagnosed before hospital discharge. Thus, it is essential to understand the physiopathology of aortic coarctation and its systemic implications on the life of the newborn and the adult to contribute to the early diagnosis of these patients. [1,2] . It has an incidence of 5-10% among all congenital heart diseases and is predominant in males, at a ratio of 2:1. It is classified as the fifth most common congenital heart disease.Its incidence in comparison with the number of births corresponds to three cases per 10,000 births.1It is a common heart disease, but it has high mortality and morbidity rates, which are associated with failure to diagnose. Echocardiography is the one of the main diagnostic modality of coarctation of the aorta especially in infants less than 6 months. Sometimes it is complicated to diagnose coarctation of the aorta either because of limited echo window or because of the presence of a large PDA. Failure or delay in the diagnosis of coarctation will lead to morbidity as well as mortality.

The aim of the study was to look for key echocardiographic parameters coarctation of the aorta in infants .

Materials and methods: During the period from October 2019 to January 2021 in Multidisciplinary Medical Centre Akfa Medline echocardiographic measurements were performed for 400 normal infants referred for echocardiography. This was compared with 25 patients with proved coarctation either by computer tomography (CT) or cardiac catheterization. The Doppler ultrasonic diagnostic apparatus used was Siemens Accuson 3000 with 2.0–5.0MHz transducer. The left ventricular long axis view, apical four-chamber view, large artery short axis view, subcostal view of abdominal aorta and suprasternal view were used in scanning with special attention to the structures of the atria, ventricles, aorta and their echocardiographic measurements performed in both groups include aortic annulus diameter, ascending aorta diameter, proximal transverse arch diameter, distal transverse arch diameter, aortic isthmus diameter, distance between aortic arch branches. Aortic valve anatomy , associated findings as well as surgical and CT diagnosis were reviewed. The ratio between the transverse arch and ascending aorta as well as between transverse arch and the distance between aortic arch branches were calculated. In addition, cusps of aortic valve compared in two groups.

Results: During the investigation period 400 normal infants and 25 infants with coarctation were reviewed. The age group were from one day to six months and the mean weight were 4.56 ± 1.35 and 3.6 ± 2.45 kg for the normal and abnormal groups, respectively. There were statistical difference in the echocardiographic parameters between the two groups regarding the transverse arch diameter with a smaller diameter in the CoA group (3.82 ± 1.15 vs 5.6 ± 1.07 mm, P value 0.0001). The ratio between the transverse arch and the ascending aorta was smaller in patients with CoA (0.47 ± 0.14 vs 0.77 ± 0.18, P value 0.0001). The distance between the left common carotid and the left subclavian arteries was longer in patients with CoA compared to those with normal arch (4.92 ± 2.39 mm vs 2.72 ± 1.53 mm, P value 0.0001). The ratio between the distance between the left common carotid and the left subclavian arteries to that of the transverse aortic arch diameter was higher in patients with CoA (1.44 ± 0.75 vs 0.49 ± 0.31, P value 0.0001). Bicuspid aortic valve was found in 82% (n=20) of patients with CoA compared to only 7.7% of patients without coarctation ( P value 0.0001).

Discussions. The reasons for the formation of CoA, like other CHDs, until now remain unclear. Being there are several theories, the first of which appeared in 1828. It suggested about violation of the connection of the 4th and 6th aortic arches from the descending its department [3-4 ]. Later J. Skoda suggested theory, the essence of which was to obliterate the PDA with the involvement of the adjacent section of the aorta in the process. The frequency of prenatal diagnosis of CoA remains unfortunately, so far low . The basis for the assumption of this defect is the presence of a direct sign - visualization of the place is narrower of the aorta and possible expansion of its proximal department. However, according to V.I. Burakovsky and L.A. Bockeria , the place of narrowing is not always clear to the locator due to the possibility of its formation after Christmas and closing the PDA. To indirect signs of vice, since the antenatal period, include: dilatation right ventricle and its hypertrophy, pulmonary dilatation of artery. They are evaluated by the polo ratio indices right ventricle to the left (normal 1.1) and pulmonary arteries to the aorta (in healthy fetuses 1,2). Increase in these indicators is the basis for the assumption the presence of obstructed ejection into the aorta [5,6]. Transthoracic echocardiography is non-invasive, inexpensive, and easily repeatable. Besides, it not only reveals the precise anatomy of CoA, but also provides much information concerning other cardiovascular structures, cardiac function and hemodynamics. Hence, color echocardiography should be a primary method for diagnosis of CoA , especially for pregnant women to avoid irradiation . The echocardiographic diagnosis of 48 of our 53 patients was in line with findings at surgery; the accuracy rate was 90.6%, which is consistent with those reported in the literature .

Echocardiography is also very useful in the postoperative evaluation of patients with CoA. The life expectancy of patients with CoA has been shown to decrease even though the operation has been successful . The postoperative patients of CoA are still at risk for such complications as persistent hypertension and complications of chronic hypertension including coronary heart disease, myocardial infarction, stroke, dissecting aneurysm and early deaths. [7- 8]

Conclusions: Regarding to our invsetigatons, it can be concluded that key echocardiographic elements of coarctation of the aorta include the presence of bicuspid aortic valve, hypoplasia of the transverse arch, smaller ratio between the transverse arch and the ascending aorta and high ratio between the distance between aortic arch branches and transverse aortic arch.