Case Coarctation
Author: OUNG Savly is a pediatric cardiologist, Head of division of pediatric cardiology/CICU, Kantha Bopha Children’s Hospital, Phnom Penh, Cambodia. The author has obtained the consent of the parents in order to report this case. Twitter/X account of Dr Savly
Contact information: oungsavly007@gmail.com
No conflict of interest to disclose.
Online: October 29th, 2023
Background
Coarctation is a congenital condition in which any segment of the Aorta may be underdeveloped or narrowed:
5-8% of congenital heart defects. Isolated coarctation in 1 per 2500 births.
Male > female
In a neonate, Coarctation of the Aorta (CoA) is typically found in a preductal location, often described as a "waist-like" narrowing.
12.6% of girls with Turner syndrome are diagnosed with Coarctation of the Aorta (CoA).
The most typical location is at the isthmus, which is just distal to the origin of the left subclavian artery.
In some cases, the aortic arch may be diffusely hypoplastic, creating an obstruction along the length of the aortic arch.
Interrupted aortic arch can be considered the extreme form of coarctation in which there is no continuity between part of the aortic arch and the descending aorta. As such, flow to the descending aorta is dependent on a patent ductus arteriosus (PDA).
The presence and significance of collateral vessels are directly proportional to the severity of the coarctation and the age of the patient.
In infants, critical coarctation can manifest when the severe narrowing at the coarctation site intensifies upon closure of the ductus arteriosus, leaving insufficient time for the development of adequate collateral vessels. This can lead to left ventricular failure and subsequent cardiogenic shock.
Case Description
The infant, a 4-week-old baby boy, was born full-term, weighing 4 kilograms. He presented with a critical illness characterized by dyspnea during feeding, which led to a diagnosis and treatment for bronchiolitis. He was delivered at 37 weeks to a healthy mother, and both the pregnancy and delivery were uncomplicated. No resuscitation was required at birth. The infant had satisfactory Apgar scores and weighed 3000 g at birth.
At 3 weeks of age, the mother noticed that the baby had difficulty breathing, especially during feeding. In the month leading up to the baby's admission to our cardiac center, the mother sought medical evaluations from private clinics, but the issue remained unresolved, and the infant's clinical condition progressively worsened.
Upon arrival, the baby appeared pale in color. Upon examination, moderate dyspnea, weak femoral pulses, and the absence of a murmur were observed. Hepatomegaly was evident, with the liver palpable approximately 3cm below the right costal margin. The baby did not have a fever. There was a notable difference in blood pressure between the upper and lower extremities: left arm (LA) 128/80mmHg, right arm (RA) 100/68mmHg, left leg (LL) 73/47mmHg, right leg (RL) 84/58mmHg. The baby had a sinus rhythm with a heart rate of 147 beats per minute, and the oxygen saturation (SpO2) level was 98% while breathing room air.
Figure 1: Chest radiography outlining a large cardiac silhouette.
Telemetry
Telemetry outlining high systemic blood pressure of upper limbs with differential blood pressure with the lower limbs.
Electrocardiogram
12-lead ECG revealed sinus rhythm, right axis deviation. No Q wave in lateral lead. No specific ST depression in all leads.
Echocardiogram
In the parasternal long-axis view, significant left ventricular dilatation and failure were observed, with an ejection fraction (EF) of 40%, all within the context of coarctation. The mitral valve functioned normally without any abnormalities.
The parasternal short-axis view showed a tricuspid aortic valve with no commissural fusion and a normal origin of coronary arteries. The ductus arteriosus was completely closed.
The apical view revealed significant left ventricular dilation and dysfunction, accompanied by moderate mitral insufficiency as indicated by color flow.
In the supersternal axis view, a left aortic arch with critical and focal stenosis at the isthmic aorta, measuring 3mm in diameter, was observed. The pressure gradient across the stenotic lesion was approximately 79mmHg. Measurements of the aorta in various locations were as follows: proximal transverse arch 8mm (z score 0.58), distal transverse arch 5.5mm (z score -1.02), aortic isthmus 3mm (z score -3.25), and descending aorta 7mm (z score 1.05).
Doppler assessment of the abdominal aorta revealed severely blunted pulsatility and peak velocities with diastolic runoff.
The infant was diagnosed with isolated critical native focal coarctation of the aorta, complicated by heart failure. After administering PGE1 at doses of 0.02 and 0.05 mcg/kg/min, we were unable to successfully reopen the ductus arteriosus. As a result, our medical team made the urgent decision to repair the coarctation via lateral thoracotomy. The surgical procedure proceeded smoothly with successful repair through end-to-end anastomosis.
Discussion
In neonates, the palpation of femoral pulses plays a crucial role in the early detection of severe coarctation of the aorta. Additionally, measuring blood pressure in all limbs provides valuable information for ruling out coarctation. Importantly, left ventricular dysfunction resulting from elevated afterload is the primary reason for urgent surgical intervention when initial attempts with PGE1 prove unsuccessful.
Conclusion:
In cases of coarctation of the aorta, it is imperative to assess the patency of the ductus arteriosus, particularly during the neonatal period. Patients with severe coarctation may develop heart failure and/or shock when the patent ductus arteriosus closes. Identifying such patients is critical to preserving ductal patency before proceeding with surgical repair.
Resected segment of the aorta with the coarctation.
Bibliography
Aortic diseases (Aortophathies), page 176, coarctation of aorta, Echocardiography in Congenital Heart Disease (Mcleod, George, et al. "Echocardiography in congenital heart disease." Progress in cardiovascular diseases 61.5-6 (2018): 468-475.)
Eckhauser, Aaron, et al. "Turner syndrome in girls presenting with coarctation of the aorta." The Journal of Pediatrics 167.5 (2015): 1062-1066.
Bhatt, Ami B., et al. "Isolated coarctation of the aorta: current concepts and perspectives." Frontiers in Cardiovascular Medicine 9 (2022): 817866.
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