Demographic data of the patients
This registry included a total 2518 patient who underwent MDCT in between 2016 and 2019. We excluded studies with incomplete, missed and lost data (Fig. 1).
The median age of the patients was 12 months (IQR 37 months), and the youngest patient was 3 days old. The eldest patient was 50 years old. 52.5% of our patients were males.
540 patients (23.37%) were in the neonatal period—first month of life. 1038 patients (44.9%) were in the infancy period (1 month–2 years).
Grown up patients with congenital heart disease (GUCH) more than 18 years old represented a minority of our patients’ population (3.6%).
1541 patients (66.7%) had congenital cyanotic heart disease. Almost half of these patients—772 patients (50%)—had a type of the tetralogy of Fallot disease spectrum either unoperated, post-shunt surgery or after total repair.
430 patients (18.6%) had previous surgical or transcatheter intervention (ex: arterial or venous shunt operation, total corrective surgery, transcatheter stent implantation, etc.) before the MDCT study.
Analysis of the study population according to the target of the MDCT study showed that
Patients with septal defects for assessment of pulmonary veins
One hundred and ninety patients (8.9%) of the study population were sent to perform the MDCT study for the evaluation of pulmonary veins because of the suspicion of anomalous pulmonary venous drainage of cardiac, supra-cardiac, and infra-cardiac types (either partial anomalous pulmonary venous drainage, or total anomalous pulmonary venous drainage).
The most common referral diagnosis was patients with sinus venosus defects, followed by patients with ASD and suspected total anomalous pulmonary venous drainage of supra-cardiac type.
Anomalous pulmonary venous drainage was also found in association with other multiple complex congenital heart disease like left atrial and right atrial isomerism, and tetralogy of Fallot.
Six patients in our registry (3.15%) had Scimitar syndrome. The MDCT ability to clearly visualize the course, site of drainage of the pulmonary veins and to identify any stenosis within their course was excellent, and the surgical details concurred with the MDCT descriptions in all of these patients (Figs. 2, 3, 4).
Patient’s with tetralogy of Fallot disease spectrum
Tetralogy of Fallot disease’s spectrum and variants was the most common congenital cyanotic heart disease in our registry. They represented almost half of the patients with congenital cyanotic heart disease 772 patients.
We included patients with common atrio-ventricular canal (CAVC) and Fallot’s tetralogy (canal Tet) in this group.
Eleven patients of the Fallot’s tetralogy disease group had partial anomalous pulmonary venous drainage of the left upper pulmonary vein into the left innominate vein representing 1.4% of theses patient.
Assessment of the pulmonary tree morphology, bifurcation pattern, and size, assessment of the major aorto-pulmonary collaterals (MAPCs), the morphology of the ductus arteriosus in cases of pulmonary atresia and coronary artery anatomy were the most common important targets in this group (Fig. 5).
Pulmonary atresia with intact interventricular septum
We had 15 patients with pulmonary atresia and intact interventricular septum, 5 of them were sent for MDCT after having their duct stented percutaneously. The incidence of right ventricular sinusoids dependent coronary circulation was 26.6% (4 patients).
Patent ductus arteriosus (PDA)
Assessment of the PDA as an isolated congenital heart disease was found in 33 patients (1.5% of the study cohort). This was done in young patients with PDA in associated with aortic coarctation, or adult patients with poor window and inability to assess the morphology, size, and the course of the duct.
Double outlet right ventricle (DORV)
Patients with double out right ventricle disease variables represented 155 patients (7.2%) of our registry, and the most common variant was the double outlet right ventricle, subaortic VSD, and severe pulmonary stenosis (65% of this group).
The main target of the study was the assessment of the pulmonary tree size and morphology, collaterals and coronary arteries. While the Taussig–Bing anomaly was present in only a minority of this group of patients and the target of the study was to exclude any associated aortic arch anomalies.
Congenitally corrected transposition of the great arteries
Patients with congenitally corrected transposition of the great vessels represented 20 patients (0.93%) in our cohort. Most of them had an associated ventricular septal defect and severe pulmonary stenosis.
We would like also to mention that 4 patients of them (20%) had an associated different degrees of congenital heart block.
Coronary artery anomalies
47 patients (2.2%) were referred to MDCT for pure evaluation of their coronary arteries.
The suspected referring diagnosis was congenital anomalies in the origin of the coronary arteries such as anomalous origin of the left coronary artery from the pulmonary artery (ALCAP syndrome (9 patients), coronary fistula (32 patients), and acquired disease as Kawasaki vasculitis (6 patients) (Fig. 6a, b).
Pulmonary artery aneurysm and peripheral pulmonary stenosis
Pulmonary artery aneurysm was the target of the study in 12 patients (0.56%). Peripheral pulmonary stenosis was the target of the study in 33 patients (1.5%); among these patients, the commonest syndrome was Alagille’s syndrome (6 patients). William’s Syndrome was the second common associated syndrome, but they are mentioned in the aortic group.
Assessment of surgical arterial shunts
Assessment of arterial shunt was performed in 150 patients.
This group included patients with Fallot’s tetralogy disease spectrum, or patients who has their shunt as the first stage of treatment of uni-ventricular repair, and other patients with two ventricles and associated severe pulmonary stenosis before their total corrective surgery.
Modified Blalock Taussig (MBT) shunt was the commonest arterial shunt among the studied cohort (145 patients), central shunt was found in minority of the patients (only 5 patients). It is worth mentioning that 43 patients had bilateral MBT shunts (Fig. 7).
Assessment of cavo-pulmonary shunts (Glenn’s and Fontan’s shunt)
Assessment of venous shunts (Glenn, Fonatain, and venous collaterals) was the target in 185 patients (8.6%); among these patients, 28 patients had bilateral bidirectional Glenn shunt.
Assessment of atrial baffles (in patients with atrial switch operations)
Transposition complexes with Atrial switch (Mustard or Senning Procedure) represent only 5 patients in our study, and assessment of the baffle was the main target of the study. We had no patients in our study post-arterial switch.
Assessment of right ventricle to pulmonary artery conduit (RV-PA conduit)
Patients with RV-PA conduit represented 33 patients in our registry. Rastelli’s operation was the most common operation among those patients (Fig. 8).
Patients with single ventricle
Single ventricle heart disease patients were seen in our cohort very early either before or after stage 1 surgery (systemic to pulmonary arterial shunt), After stage 2 surgery (Glenn or Hemi-Fontan procedure), only one patient in our cohort was seen after stage 3 surgery (Fontan’s shunt).
Aortic disease, truncus arteriosus, aorto-pulmonary window, rupture sinus of Valsalva, collagen, and connective tissue syndromes and diseases
Assessment of aortic disease like bicuspid aortic valve associated aortopathy (60 patients), native coarctation (280 patients), post-coarctation surgical repair (23 patients), post-coarctation stenting (19 patients), aortic interruption (16 patients), complete and incomplete vascular rings (40 patients), truncus arteriosus (28 patients), aortopulmonary window (20 patients), supravalvular aortic stenosis (21 patients), arterial tortuosity syndrome (2 patients), Loeys–Dietz syndrome (1 patient), Ehlers–Danlos syndromes (1 patient), Marfan syndrome (4 patients), 3 patients with rupture sinus of Valsalva (Fig. 9a–e).
Surgical re-entry high risk patients
Sternal re-entry in high-risk patients was the indication in 22 patients. All had previous surgical palliative or total repair procedures. Fallot’s tetralogy total repair, severe pulmonary regurgitation, and dilated right ventricular outflow tract that was adherent to the sternal surface were the most common indication. Supravalvular aortic stenosis with pseudoaneurysm, aneurysm or recurrence was the second most common indication.
The study was done to plan for surgical re-entry before reconstruction of the right ventricular outflow tract, pulmonary valve implantation, or aortic repair.
Topsy Turvy syndrome
We had one case with Topsy Turvy heart syndrome (Fig. 10).
Overlap between groups
Patients with right and left atrium isomerism were present in all the mentioned groups, according to the predominant target of the study and associated intracardiac lesions.
Patients with functionally single ventricle and univentricular repair were mentioned in details in the sections of arterial, and venous shunts.
Controversial and/or inappropriate indications
Controversial and/or inappropriate indications for MDCT were found in 30 patients (1.4%). In this group, cardiac catheterization, direct surgical intervention, other investigation like echocardiography with bubble study were deemed by us to be the next step or next investigation of choice and MDCT results did not add significant value for the evaluation of the patients, deeming the selection of the MDCT study to be rather inappropriate. 10 patients had mild pulmonary stenosis with associated subaortic membrane, 5 patients had ventricular septal defect and PDA, 8 patients had dilated coronary sinus with suspected persistent left SVC, 4 patients had DORV, VSD, unprotected pulmonary circulation, and 3 patients had suspected VSD.
Declining the study
We have declined doing the MDCT for three patients in this registry.
All had an associated congenital pelvi-uretric junction obstruction, and/or posterior ureteral valve with recurrent urinary tract infections, hydroureter, hydronephrosis, and elevated kidney function test with reduced glomerular filtration rate. After consulting with their referral physicians, they were referred to do other investigation such as cardiac MRI, or they were referred directly to surgery.
Diagnostic accuracy of the study
The ability of the MDCT study to accurate diagnose or exclude the patient’s condition was assessed by feedback and communication with the referral center, surgeon, and cardiologist.
The diagnostic yield excellent based on either intraoperative finding and data of the patients who underwent total and palliative procedures, or patient who underwent invasive cardiac catheterization.
Missing of the diagnosis and or missing data was encountered in two patients (less than 1 %) in this registry, and two of them had anomalies of the coronary artery origin with contradicting clinical and MDCT report data, where MDCT missed the diagnosis of anomalies origin of the left main coronary artery from the pulmonary artery (ALCPA) syndrome due to poor image quality of the study, rapid heart rate of the patient combined with motion and breathing artifacts. The diagnosis was confirmed by invasive catheterization in this patient.
The second patient had incomplete assessment of the course and termination of coronary artery fistula from the left circumflex artery to the right ventricle basal inferior wall near the coronary sinus entry, and it was also delineated by invasive catheterization.
Analysis of the incidence of the procedure-related complication
Venous access data and access-related complications
Intravenous access was obtained in the upper limb in 56.7% of the patients, in the lower limb in 13.5% of the patients, in the neck veins in 23.5% of the patients, in the scalp veins in 4.6% of the patients, anterior abdominal wall in 1.4% of the patients. Simultaneous accesses in the upper and lower halves of the body were obtained in less than 1% of the patients.
Difficulty in obtaining the venous access with more than three trials to insert the venous cannula was encountered in 3% of the patients. Postponing the study due to failure to obtain the venous access was encountered very rarely in less than 0.5% of the patients.
Twelve patients—0.51% of the patients—had extravasation of the contrast material in the subcutaneous tissue due to rupture of the veins, with mild erythema and subcutaneous edema. Immediate interruption of contrast material and/or saline injection was done as the pressure tracing showed abrupt rise or the patient reported pain during injection.
The volume of the contrast material delivered to the circulation and motion artifacts secondary to pain from the extravasated contrast rendered the study uninterpretable with very poor images in only 5 patients of this group, and the study was repeated after securing another venous access.
The image quality was satisfactory in the other 7 patients with no need to repeat the study.
Extravasation of the contrast material and vein rupture was managed conservatively in all of the patients with warm fomentation, skin care, and local application of anti-inflammatory, antiedema creams. None of these patients developed delayed complication like skin ulceration or required any further management.
Allergic reactions
Twenty-four patients—1.03% of the study population—had allergic reactions from contrast material injection. All reactions were minor (skin erythema, wheals, and itching); they were managed by antihistaminic. We did not encounter any severe forms of allergic reactions among our study population ex: stridor with bronchospasm and wheezes or anaphylaxis, etc.
Side effects of anesthesia
Transient apnoea and bradycardia were the most common encountered side effects in 3.1% and 2.4% of the patients, respectively, with uneventful continuation of the study.
Hiccough and vomiting were less frequent. Hiccough lead to some difficulty in interpretation of the study images due to the sudden high amplitude motion artifacts. We used the ECG gating to perform multiple reconstructions of the images, and none of these patients needed to repeat the study.
Agitation and delayed recovery from anesthesia were only rarely encountered.
Cyanotic spells
Cyanotic spell occurred in seven patients just after administration of anesthesia or immediately after the end of the study. All of the patients were successfully managed according to the standardized protocols without any cardiac or neurological complications. And the study was completed successfully.
Mortality
Unfortunately, we have encountered one case of mortality 0.04% that occurred 3 days after the study. This patient had multisystem congenital anomalies, dysmorphic features with neurological malformation. He had apnoea, bradycardia just after the study. He was successfully resuscitated, intubated, and transferred to the NICU; however, his condition deteriorated furtherly.