Persistent left superior vena cava (PLSVC) is the most common congenital malformation of thoracic venous return and is present in about 0.3 to 0.5% of individuals in the general population and 1.5%–10% of patients with other congenital heart abnormalities.^[1] It is a marker of embryopathy ^[2] and occurs due to failure of involution of the left horn of the embryonic sinus venosus, left anterior vein and common cardinal vein^.[1] In normal conditions, antenatally two superior vena cava’s are present, right and left. Over a period of time in normal conditions, the left superior vena cava regresses and only the right one persists. If the left superior vena cava is persistent after birth, this condition is known as a Persistent left superior vena cava and this may be associated with different congenital heart diseases and other non-cardiac anomalies.^[3]

A PLSVC often co-occurs with the right superior vena cava within an otherwise structurally normal heart, in 80 to 90% of cases,^[4] and may also be accompanied by other congenital heart abnormalities such as anomalous connections of the pulmonary veins, coarctation of aorta, Tetralogy of Fallot, transposition of the great vessels as well as dextroversion^{.[1,5, 6]} It may at times also be associated with disturbances of cardiac impulse formation and conduction, including varying degrees of heart blocks, supraventricular arrhythmias and Wolff Parkinson White syndrome^{[7, 8, 9]}, which makes detection and early diagnosis of PLSVC, of paramount importance.^{[10, 11, 12]}

Here we will try to focus on the diagnosis of PLSVC by 2D echocardiography and study the association of PLSVC with different types of CHD and other extra cardiac congenital anomalies. This was carried out by taking different variables like age, gender, associated CHDs, Birth weight, height, Gestational age, Auscultatory findings and Parental consanguinity.

AIM: To study Persistent left superior vena cava in children with congenital heart diseases and its association with different types of CHD.

OBJECTIVES

• To study clinical profile of PLSVC in children with congenital heart diseases
• To find out the association of PLSVC with different types of congenital heart diseases

Inclusion criteria:

• All patients in the age group of 0-12 years diagnosed with PLSVC by 2-D echocardiography
• Parents/caretakers willing to give consent for the study

Exclusion Criteria:

• Acquired heart disease patients
• Patients above the age of 12years with PLSVC

All patients satisfying above inclusion and exclusion criteria were enrolled in our study.

Findings of PLSVC were noted down on 2D Echocardiography report. The required information of all patient’s with PLSVC such as their demography (age, gender, height, weight at the time of examination, gestational age at the time of birth and birth weight), clinical examination findings (SPO2, pulse rate, auscultatory findings) and significant antenatal history (birth order, mothers age at conception, parental consanguinity) were collected and written in a Case Record form.

Study Design: Retrospective Descriptive Study

Study Setting: Rural Tertiary Care Centre.

Study Population: All children in the age group of 0-12 years diagnosed with persistent left superior vena cava by 2-D Echocardiography were included in the study.

Sample Size: Sample size as calculated by using OpenEpi software, considering frequency of Persistent Left Superior Vena Cava to be 0.5%, with confidence interval 80% is 30. Considering 3 dropouts, total sample size calculated is:

TOTAL SAMPLE SIZE => n = 30 + 3 = 33

Study Period: 1 year.

Study Conduct:

• Patient satisfying the above inclusion and exclusion criteria were studied for the following variables: Type of congenital heart disease, Age, Gender, Height, Gestational Age at birth, Birth weight, SPO2, Pulse rate, General examination(any obvious external congenital anomaly), Auscultatory findings, Birth order, Mothers age at conception, Parental
• 2-D Echocardiography examination assessed PLSVC with and without association with Congenital Heart Diseases like Ventricular Dysfunction, Atrial septal defect (ASD), Ventricular Septal Defect (VSD), Patent ductus arteriosus (PDA), Atrioventricular septal defect (AVSD)S, Aortic Stenosis, Pulmonary stenosis, Aortopulmonary window, Coarctation of Aorta, Tetralogy of Fallot (TOF), Double outlet right ventricle, Total anomalous pulmonary venous connection (TAPVC), Partial Anomalous Pulmonary Venous Connection (PAPVC),Transposition of Great Arteries(TGA),Truncus Arteriosus, Pulmonary Atresia, Tricuspid atresia, Epstein Anomaly of Tricuspid Valve etc.
• Age was taken on the basis of 2D echocardiography
• Height was measured with the help of an infantometer / stadiometer and was recorded in CRF
• Weight was measured with the help of a digital weighing scale and later recorded in a case record form
• Gestational age at the time of birth and birth weight will be taken on
• SPO2 was measured with the help of a Pulse Oximeter in sitting/supine position of Right upper limb and one of the lower limb:
• Pulse rate taken on right radial artery in sitting position was recorded in the case record form
• On auscultation, First heart sound, second heart sound and murmur (if present) were

Birth order, mother’s age at conception and parental consanguinity were noted down from history of the patient.

Statistical Analysis: All the data was collected and entered into excel sheet.All variables and data were described using the above mentioned descriptive statistics.The data was pooled and analysed using descriptive statistics as mentioned in the variable table and inferences were drawn.

CONFIDENTIALITY

The identity of the subjects involved in the study is bound in strict confidence. The rest of the data will only be available to the investigator carrying out the study and to the regulatory authorities. Break in confidentiality is possible only after detailed review by the investigator and with the permission of the ethical committee.

 A total of 33 patients were taken as study subjects from January 2020 to September 2022. Data was recorded from previous IPD files and 2D Echocardiography reports and entered into case record forms. Relevant data which included the variables and satisfied the inclusion criteria were included in the study. Observations of the results have been tabulated as below:

Demographic Profile : TABLE 1

From Table 1, Out of total 33 cases about 55% patients were females while 45% of them were males, posing the incidence of PLSVC to be almost similar in both genders.

Out of the total 33 cases, 79% were newborns and were detected to have PLSVC in the first month of life followed by 9% of infants and toddlers while only 3% were detected above the age of 5 years. This indicates that maximum of the cases were detected to have PLSVC very early on in life, which can help us eliminate any major risk factors that might accompany later in life.

Among the total 33 cases taken it was observed that maximum, 55% of these children were born at term gestation while an almost equal number, 45% were preterm gestation. The complications in these children who were born at preterm gestation were also much more in severity as compared to the ones born at term gestation.

A staggering 91% of the total 33 cases were found to have been born with a low birth weight in association with their Gestational Age while only 9% were found to be Appropriate for Gestational Age. No patiends were found to have a birth weight on the higher side.

Among the total 33 cases a massive amount of 91% of the patients were underweight and hence showing signs of development below the average values, while only a mere 9% had a normal weight according to growth standards.

One of the other striking findings is that the height/length of 79% of the total number of cases was found to be below the 3^rd percentile according to growth standards while only 21% were found to be between the 3^rd and 97^th percentile. No cases were found to have a height above the 97^th percentile.

TABLE 2

Figure 1

Table 2 along with the accompanying pie chart (Figure 1) shows the incidence of the given CHDs with Persistent Left Superior Vena Cava.

Out of the total 33 cases, the maximum, i.e. 16% are associated with Patent Ductus Arteriosus (PDA) after the 3^rd day of life followed by 16% with Ventricular Septal Defects, 11% with Atrial Septal Defects (ASD), 9% with Tricuspid Regurgitation (TR), 7% with dextrocardia, 4% with Coarctation of Aorta (COA) followed by only 2% which were associated with Mitral Stenosis (MS), Pulmonary Stenosis and Tetralogy of Fallot(TOF) each. A total of 31% of cases of PLSVC were not associated with any CHDs.

Table 3: SpO2 in patients with PLSVC:

SpO2 levels are observed in order to check for the respiratory sufficiency of the patient. From Table 3/Figure 2, In the total 33 cases that were taken, a good 73% were found to have SpO2 levels within the normal range of 96% to 100% , 21% to have mild respiratory insufficiency with SpO2 levels between 91% to 95% and only 6% of the total cases were found to have levels below 90%.

This indicates that while the number of incidences of CHDs might increase with PLSVC, most of them have a preserved circulatory and respiratory function.

Figure 2

Table 4: General examination findings in children with PLSVC:

From Table 4/Figure 3 , It was noted that a staggering 64% of total cases were found to have positive general examination findings, such as limb deformities, respiratory distress soon after birth in varying degrees, failure to thrive, developmental delay and in some cases was also associated with Marfan’s syndrome as well as Kartagner’s syndrome. About 36% of the total cases were found to have no physical findings and were asymptomatic.

Figure 3

Table 5: Auscultatory findings in patients with PLSVC:

Though a large number of the total cases were found to have positive examination findings, only about 24% of the total were found to have auscultatory findings like a systolic murmur or a diastolic murmur. In the rest of 76%, heart sounds S1 and S2 were found to be normal and no murmurs could be auscultated(Table 5/Figure 4).

Figure 4

Persistent left superior vena cava may be a benign finding in patients with an anatomically normal heart. In most conditions, its drainage occurs through the coronary sinus to the right atrium without hemodynamic consequences.

The prevalence of PLSVC varies between 2% and 5% in adults with congenital heart defects and this prevalence increases even more in adults who have pulmonary atresia, pulmonary venous return abnormality, PS, TGA, AVSD and Coarctation of Aorta. ^{[13, 14, 15]}

The existence of PLSVC as a congenital vascular abnormality represents clinical significance in children who undergo central venous interventions, pacemaker implantation and intrathoracic surgery. Hence, PLSVC may be related with the postoperative instability of these children. ^{[16, 17 ]} Thus, the early diagnosis of PLSVC and the accompanying heart defects is of utmost importance.

In this study 2D echocardiography reports of 33 patients were analyzed. An association between different Congenital Heart Diseases and PLSVC was found, which showed that it was more commonly associated with a patent ductus arteriosus (PDA), Ventricular septal defects (VSD) and atrial septal defects (ASD) which is on par with the research conducted by Serdar Kula, Ayhan Cevik, Cihat Sanli, Ayhan Pektas, Fatma Sedef Tunaoglu, Ayse Deniz Oguz1 and Rana Olgunturk in the year 2011 showing similar percentages of the above mentioned CHDs in attribution with a persistent left superior vena cava^[18].

Amongst the 33 cases taken, about 55% were females and 45% were males which was found in line with the study of Serdar Kula et al. conducted in the year 2011^[18]. The mean age of the patients was 54.58 ±

54.20 months, in a range of 0 to 208 months which collaborates with the above-mentioned study statistics. All of these cases were diagnosed by 2D echocardiography which has somewhat decreased the mean age as seen in most recent studies.

This study also shows an increased incidence of preterm birth in children with a persistent left superior vena cava which has been previously stated by Vrinda Nair et al. in their research paper on Persistent Left Superior Vena Cava: A Marker for Fetal Anomalies^[19] in the year 2017 stating that a PLSVC along with other CHDs may lead to premature rupture of membranes leading to preterm birth of the neonate.

One of the most striking findings observed were the consistently observed low birth weight in children with PLSVC associated with CHDs. This is on par with the study conducted by RM Cerbo et al.^[20] in the year 2015 which correlates cerebral perfusion with CHD in children and can be attributed with circulatory disturbances that may be caused due to a congenital heart defect.

The physical examination findings in this study reveal different malformations that may or may not be associated with the underlying CHD accompanying PLSVC such as limb deformities, respiratory distress soon after birth, and in some cases even hepatomegaly and splenomegaly. It may also be associated with syndromes such as Marfan’s syndrome and Kartagner’s syndrome in some cases. Similar results were obtained by C. Berg et al. in the year 2006. ^[21]

Associated auscultatory findings found in this study were diverse and often related to the associated CHD in the patient that a persistent left superior vena cava itself. Patients with a VSD or an AVSD often had a systolic murmur present on auscultation while a variation may be observed in cases occurring in association with a patent ductus arteriosus or mitral stenosis producing a diastolic murmur.

A strong association was also found between PLSVC and AVSD in patients with Down’s syndrome by Ghada Sheikh Eldin et al.^[22] in the year 2013 but similar results could not be obtained in this study due to a shorter study period and use of only 2D echocardiography reports as the source of the case, but adequate data was collected on the basis of these reports to map the incidence of persistent left superior vena cava and to correlate its associations with different types of CHDs.

This study maps the incidence of Persistent Left Superior Vena Cava in children between the age group of 0 to 12 years and correlates it with the association of different CHDs with PLSVC.

PLSVC is a rare thoracic anomaly observed in about 0.3 to 0.5% of individuals in the general population and 1.5%–10% of patients with other congenital heart abnormalities. It is associated with different types of CHDs, most common of which observed in the study were a Patent Ductus Arteriosus, Ventricular Septal Defects, Atrial Septal Defects, Total Anomalous Pulmonary Venous Return and in some cases also Tricuspid Regurgitation, Dextrocardia, Congenital Mitral Valve Stenosis, Congenital Pulmonary Stenos as well as Tetralogy of Fallot.

Its incidence is almost similar in both males and females. It is in many cases associated with premature birth of the child due to premature rupture of membranes leading to a low birth weight in the child. This may in later stages hamper the appropriate development of the child and may also lead to failure to thrive.

In cases associated with complex CHDs, these children may also have physical findings such as limb deformities, face deformities, development of Respiratory Distress in neonatal age and later in life lead to poor performance in school due to early fatigue in the child. PLSVC also poses to be a risk factor in various cardiothoracic surgeries performed in children suffering from CHDs and may even lead to life threatening arrythmias.

Hence, early diagnosis of PLSVC is of utmost importance and this can be provided in tertiary health centers all over the world which provide with adequate resources for appropriate diagnosis and treatment of such children.

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19. Persistent Left Superior Vena Cava: A Marker for Fetal Anomalies Vrinda Nair1, Kamran Yusuf1, Weiming Yu2,3, Hafez AlAwad4, Kathy Paul5 2017, Society for Pediatric Pathology All rights reserved. Reprints and permissions: sagepub.com/journalsPermissions.nav DOI: 1177/1093526616686008
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