Congenital heart disease research landscape in the Arab world: a 25-year bibliometric review.

Background: While research on congenital heart disease has been extensively conducted worldwide, comprehensive studies from developing countries and the Arab world remain scarce. Aim: This study aims to perform a bibliometric review of research on congenital heart disease in the Arab world from 1997 to 2022. Methods: We analyzed data from the Web of Science, encompassing various aspects such as topics, countries, research output, citations, authors, collaborations, and affiliations. This comprehensive science mapping analysis was done using the R statistical software's Bibliometrix Package. Results: The research output from Arab countries over the 25 years showed an average annual growth rate of 11.5%. However, Arab countries exhibited lower research productivity than the United States and Europe, with a 24-fold difference. There was substantial variation in research output among 22 Arab countries, with five countries contributing to 78% of the total publications. Most of the published research was clinical, with limited innovative contributions and a preference for regional journals. High-income Arab countries displayed higher research productivity and citation rates than their low-income developing counterparts. Despite being categorized as upper-middle-income, post-conflict countries exhibited low research productivity. About one-quarter of the published articles (26%) resulted from collaborative efforts among multiple countries, with the United States being the most frequent collaborator. Enhanced research productivity and impact output were strongly associated with increased international cooperation. Conclusion: Research productivity in the Arab region closely correlates with a country's GDP. Success hinges on governmental support, funding, international collaboration, and a clear research vision. These findings offer valuable insights for policymakers, educational institutions, and governments to strengthen research programs and nurture a research culture.

Cardiac manifestations and short-term outcomes of multisystem inflammatory syndrome in Middle Eastern children during the COVID-19 pandemic: a case series.

We herein report on a series of four patients presented to our tertiary care centre with features of multisystem inflammatory syndrome in children and cardiac involvement. Two of our patients had recent exposure to a COVID-19-positive patient, one had recent documented infection, and another had no known positive contact. All the patients were tested positive for severe acute respiratory syndrome coronavirus 2 immunoglobulin G antibody at the time of presentation. All of them fulfilled the diagnostic criteria according to the World Health Organization Centers for Disease Control or the British guidelines for MIS-C (fever for ≥3 days, multisystem involvement (at least two), elevated markers of inflammation, and no other alternative diagnosis).Cardiac involvement was variable ranging from isolated ectasia of the coronary arteries to full-blown pancarditis such as severe biventricular dysfunction, multi-valvar involvement, and pericardial effusion.All our patients received intravenous immunoglobulin (2 g/kg), methylprednisolone, and aspirin and some required inotropic support and ICU admission.Remarkably, all our patients showed significant improvement in their cardiac disease within a few days as evident on serial echocardiographic evaluation. However, we stress the need for long-term follow-up as one of our patients demonstrated mild LV myocardial scarring as evident by gadolinium late enhancement on a cardiac MRI.

Balloon Valvuloplasty for Congenital Aortic Stenosis: Experience at a Tertiary Center in a Developing Country.

BACKGROUND: Aortic valve stenosis accounts for 3-6% of congenital heart disease. Balloon aortic valvuloplasty (BAV) is the preferred therapeutic intervention in many centers. However, most of the reported data are from developed countries. MATERIALS AND METHODS: We performed a retrospective single-center study involving consecutive eligible neonates and infants with congenital aortic stenosis admitted for percutaneous BAV between January 2005 and January 2016 to our tertiary center. We evaluated the short- and mid-term outcomes associated with the use of BAV as a treatment for congenital aortic stenosis (CAS) at a tertiary center in a developing country. Similarly, we compared these outcomes to those reported in developed countries. RESULTS: During the study period, a total of thirty patients, newborns (n = 15) and infants/children (n = 15), underwent BAV. Left ventricular systolic dysfunction was present in 56% of the patients. Isolated AS was present in 19 patients (63%). Associated anomalies were present in 11 patients (37%): seven (21%) had coarctation of the aorta, two (6%) had restrictive ventricular septal defects, one had mild Ebstein anomaly, one had Shone's syndrome, and one had cleft mitral valve. BAV was not associated with perioperative or immediate postoperative mortality. Immediately following the valvuloplasty, a more than mild aortic regurgitation was noted only in two patients (7%). A none-to-mild aortic regurgitation was noted in the remaining 93%. One patient died three months after the procedure. At a mean follow-up of 7 years, twenty patients (69%) had more than mild aortic regurgitation, and four patients (13%) required surgical intervention. Kaplan-Meier freedom from aortic valve reintervention was 97% at 1 year and 87% at 10 years of follow-up. CONCLUSION: Based on outcomes encountered at a tertiary center in a developing country, BAV is an effective and safe modality associated with low complication rates comparable to those reported in developed countries.

Founder Mutation in N Terminus of Cardiac Troponin I Causes Malignant Hypertrophic Cardiomyopathy.

BACKGROUND: Cardiac troponin I (TNNI3) gene mutations account for 3% of hypertrophic cardiomyopathy and carriers have a heterogeneous phenotype, with increased risk of sudden cardiac death (SCD). Only one mutation (p.Arg21Cys) has been reported in the N terminus of the protein. In model organisms, it impairs PKA (protein kinase A) phosphorylation, increases calcium sensitivity, and causes diastolic dysfunction. The phenotype of this unique mutation in patients with hypertrophic cardiomyopathy remains unknown. METHODS: We sequenced 29 families with hypertrophic cardiomyopathy enriched for pediatric-onset disease and identified 5 families with the TNNI3 p.Arg21Cys mutation. Using cascade screening, we studied the clinical phenotype of 57 individuals from the 5 families with TNNI3 p.Arg21Cys-related cardiomyopathy. We performed survival analysis investigating the age at first SCD in carriers of the mutation. RESULTS: All 5 families with TNNI3 p.Arg21Cys were from South Lebanon. TNNI3 p.Arg21Cys-related cardiomyopathy manifested a malignant phenotype-SCD occurred in 30 (53%) of 57 affected individuals at a median age of 22.5 years. In select carriers without left ventricular hypertrophy on echocardiogram, SCD occurred, myocyte disarray was found on autopsy heart, and tissue Doppler and cardiac magnetic resonance imaging identified subclinical disease features such as diastolic dysfunction and late gadolinium enhancement. CONCLUSIONS: The TNNI3 p.Arg21Cys mutation has a founder effect in South Lebanon and causes malignant hypertrophic cardiomyopathy with early SCD even in the absence of hypertrophy. Genetic diagnosis with this mutation may be sufficient for risk stratification for SCD.

Premature Valvular Heart Disease in Homozygous Familial Hypercholesterolemia.

Valvular heart disease frequently occurs as a consequence of premature atherosclerosis in individuals with familial hypercholesterolemia (FH). Studies have primarily focused on aortic valve calcification in heterozygous FH, but there is paucity of data on the incidence of valvular disease in homozygous FH. We performed echocardiographic studies in 33 relatively young patients (mean age: 26 years) with homozygous FH (mean LDL of 447 mg/dL, 73% on LDL apheresis) to look for subclinical valvulopathy. Twenty-one patients had evidence of valvulopathy of the aortic or mitral valves, while seven subjects showed notable mitral regurgitation. Older patients were more likely to have aortic valve calcification (>21 versus ≤21 years: 59% versus 12.5%; p = 0.01) despite lower LDL levels at the time of the study (385 versus 513 mg/dL; p = 0.016). Patients with valvulopathy were older and had comparable LDL levels and a lower carotid intima-media thickness. Our data suggests that, in homozygous FH patients, valvulopathy (1) is present across a wide age spectrum and LDL levels and (2) is less likely to be influenced by lipid-lowering treatment. Echocardiographic studies that focused on aortic root thickening and stenosis and regurgitation are thus likely an effective modality for serial follow-up of subclinical valvular heart disease.

Variable expressivity and co-occurrence of LDLR and LDLRAP1 mutations in familial hypercholesterolemia: failure of the dominant and recessive dichotomy.

BACKGROUND: The familial inherited genetic disorder of lipoprotein metabolism affects more than 10 million individuals around the world. Lebanon is one of the several endemic areas for familial hypercholesterolemia (FH) with a founder mutation in the low-density lipoprotein cholesterol receptor (LDLR) gene, responsible for most of the cases. We have previously shown that 16% of all familial cases with hypercholesterolemia do not show genotype segregation of LDLR with the underlying phenotype. METHODS: We used Sanger sequencing to genotype 25 Lebanese families with severe FH for the gene encoding the LDLR-associated protein (LDLRAP1), responsible for the recessive form of the disease starting with the four families that did not show any genotype-phenotype correlation in our previous screening. RESULTS: We showed that the previously reported p.Q136* variant is linked to the hypercholesterolemia phenotype in the four families. In addition, we showed a variable phenotype between families and between members of the same family. One family exhibits mutations in both LDLR and LDLRAP1 with family members showing differential phenotypes unexplained by the underlying genotypes of the two genes. CONCLUSION: The p.Q136* variant in LDLRAP1 is yet another founder mutation in Lebanon and coupled with the LDLR p.C681* variant explains all the genetic causes of FH in Lebanon.

The Muscle-Bound Heart.

Hypertrophic cardiomyopathy (HCM) is a familial cardiac disease manifested in a wide phenotype and diverse genotype and, thus, presenting unpredictable risks mainly on young adults. Extensive studies are being conducted to categorize patients and link phenotype with genotype for a better management and control of the disease with all its complications. Because the full mechanisms behind HCM are still not revealed, therapeutics are not definitive. Further research is to be conducted for the generation of a complete picture and directed therapy for HCM.

Incessant Long R-P Tachycardia.

A 13-year-old boy had a positive P wave in V1 with a negative P wave in lead I, aVL, and aVR, as well as a positive P wave in the inferior leads, which correlated with a left atrial appendage (LAA) atrial tachycardia (AT) focus. P-wave morphologies can provide clues regarding an AT's origin, and this P-wave negative in lead I favored LAA AT. Careful mapping along the atria and coronary sinus to determine the earliest site of activation for the surface P wave is a reliable method for precisely localizing the AT origin as a target for catheter ablation.

NKX2-5 mutations in an inbred consanguineous population: genetic and phenotypic diversity.

NKX2-5 mutations are associated with different forms of congenital heart disease. Despite the knowledge gained from molecular and animal studies, genotype-phenotype correlations in humans are limited by the lack of large cohorts and the incomplete assessment of family members. We hypothesized that studying the role of NKX2-5 in inbred populations with homogeneous genetic backgrounds and high consanguinity rates such as Lebanon could help closing this gap. We sequenced NKX2-5 in 188 index CHD cases (25 with ASD). Five variants (three segregated in families) were detected in eleven families including the previously documented p.R25C variant, which was found in seven patients from different families, and in one healthy individual. In 3/5 familial dominant ASD cases, we identified an NKX2-5 mutation. In addition to the heterogeneity of NKX2-5 mutations, a diversity of phenotypes occurred within the families with predominant ASD and AV block. We did in fact identify a large prevalence of Sudden Cardiac Death (SCD) in families with truncating mutations, and two patients with coronary sinus disease. NKX2-5 is thus responsible for dominant familial ASD even in consanguineous populations, and a wide genetic and phenotypic diversity is characteristic of NKX2-5 mutations in the Lebanese population.

Low-density lipoprotein levels and not mutation status predict intima-media thickness in familial hypercholesterolemia.

BACKGROUND: Intima-media thickness (IMT) is a well-described marker of cardiovascular disease. In this study we aim to determine whether low-density lipoprotein (LDL) levels and disease-related mutation status can predict IMT in patients with severe familial hypercholesterolemia (FH) referred for or on LDL apheresis. METHODS: Genetic screening, lipid profile testing, and IMT measurements were performed on a series of 33 severe FH patients (19 homozygous) on LDL apheresis treatments (LDL 447 ± 151 mg/dL, age range 6-60 years). Data were then compared with literature IMT-LDL data for normal subjects, mild FH patients, and severe FH patients (18, 41, and 6 studies, respectively). RESULTS: Age-adjusted IMT was linearly related to LDL levels over a wide range of values (<500 mg/dL), except for the severe FH no-apheresis cohort. Alternatively, our severe FH population (mostly on apheresis) did follow the mild FH/control age-adjusted IMT-LDL relation. CONCLUSIONS: In severe FH, measuring LDL levels is more predictive of increased IMT than genetic screening.

Novel percutaneous femoral arterial-transthoracic approach for closure of ascending aortic pseudoaneurysm with a septal occluder device in a child.

Ascending aortic pseudoaneurysms are a rare complication following cardiac surgery. Their traditional surgical management carries high morbidity and mortality, especially in patients with multiple comorbidities. Transcatheter closure of these pseudoaneurysms using a septal occluder device has been previously reported in adults as an alternative approach with fewer complications. We report the first case of a novel percutaneous femoral arterial-transthoracic approach for exclusion of an ascending aortic pseudoaneurysm with an Amplatzer atrial septal occluder device in a 9-year-old child with Takayasu's arteritis.

Rupture of sinus of Valsalva aneurysm with aorto-biventricular fistulas and right-ventricular outflow tract obstruction: a unique association.

Sinus of Valsalva aneurysms are a rare entity. Rupture of such aneurysms is a major cause of aortocardiac fistulas usually occurring between the right sinus of Valsalva and right cardiac chambers. We report an exceptional case of a ruptured congenital sinus of Valsalva aneurysm with fistulas involving both the right- and left-ventricular outflow tracts and causing RVOT obstruction. We also demonstrate the utility of computed tomography angiography and transesophageal echocardiography in diagnosing these fistulas.

Homozygous familial hypercholesterolemia in Lebanon: a genotype/phenotype correlation.

Familial hypercholesterolemia (FH) is an inherited disease characterized by the deposition of LDL in tissues causing premature atherosclerosis. Many genes are implicated in FH resulting in a large variability in the phenotype. DNA sequencing of the LDLR gene was done for forty patients clinically diagnosed with homozygous FH and forty family members variably affected. Patients underwent noninvasive heart and vascular studies. Statistical and pedigree analyses were used to correlate the different genotypes with the phenotypes. The prevalence of homozygosity at the Lebanese allele (2043C>A) is 45%. However, 27.5% of the patients have no mutations at all in the LDLR gene, and 27.5% are either heterozygous for the 2043C>A mutation, heterozygous for a mutation in another exon of the LDLR gene, or combined heterozygous for two different mutations. We confirm previous reports on the higher prevalence of FH in Lebanon. Our results do, however contradict previous reports on an assumed higher prevalence among the Christian Lebanese. Mutations in the LDLR especially combined heterozygosity can cause a severe phenotype similar to the homozygous mutation in the Lebanese allele. This information is particularly important in targeting the more prevalent heterozygotes in the general population with early diagnosis and intervention.

The status of pediatric cardiology at a tertiary center in Lebanon.

PROBLEM: Cardiac disease, both congenital and acquired, contributes significantly to morbidity and mortality in children. METHODS: This article describes the status of pediatric cardiology at the Children's Heart Center in the American University of Beirut Medical Center. It addresses the available clinical services as well as the research and educational activities that are present at a tertiary center in Lebanon, a developing country with a population of 4 million. RESULTS: Lebanon has witnessed major developments in the field of pediatric cardiology over the past few years. About 650 babies are born with heart disease every year, with more than 425 needing treatment. Nearly all types of interventional catheterization procedures are currently being performed. About 300 open and closed pediatric cardiac surgeries are performed per year in Lebanon. In 2008, the in-hospital surgical mortality rate at our center was 2.6%, reflecting the good level of care in the treatment of children with congenital heart disease (CHD) in Lebanon. Basic research in the field of pediatric cardiology is emerging at our center. Our team has been studying the effect of chronic hypoxemia on the neonatal myocardium in an animal model of chronic hypoxia, as well as the study of molecular basis of CHD. CONCLUSION: Appropriate identification of cardiac disease, its epidemiology, and outcome is of utmost importance in guiding adequate care. Centralization of facilities is important to improve results and level of care.

Absence of GJA1 gene mutations in four patients with anomalous left coronary artery from the pulmonary artery (ALCAPA).

PROBLEM: Anomalous left coronary artery from the pulmonary artery (ALCAPA) is a rare form of congenital heart disease with no known genetic cause. It is usually diagnosed within the first year of life; it results in myocardial cell death, congestive heart failure and lethality if left untreated. Connexin 43alpha1 is a member of the gap junction family of proteins demonstrated by animal studies to have a role in coronary artery patterning during development. No previous studies have investigated the role of this gene in patients with ALCAPA. METHODS: We forth herein describe the clinical presentation of four patients who presented to the Children's Heart Center at AUBMC and had the final diagnosis of ALCAPA. Screening the GJA1 gene coding for connexin 43alpha1 was undertaken. RESULTS: No mutations were found in the patients or their parents, except for one polymorphism in one of the parents in the 3' untranslated region. All four patients underwent surgical repair with excellent outcome. CONCLUSION: This paper raises the awareness of this rare condition enabling physicians to reach the adequate diagnosis which will allow early surgical intervention and better prognosis. Our patient sample did not exhibit any evidence of association between connexin 43alpha1 and the clinical phenotype.

Pulmonary hypertension in children and young adults with sickle cell disease: evidence for familial clustering.

BACKGROUND: Pulmonary hypertension (PHTN) is increasingly recognized as a serious complication of sickle cell disease (SCD). Our objective was to determine the prevalence of PHTN and identify factors associated with PHTN among children and young adults with SCD in Lebanon. PROCEDURE: From June 2004 to June 2008, 90 patients were studied. Correlation of TRV with LDH, mean corpuscular volume (MCV), fetal hemoglobin (HbF), hydroxyurea use, and G6PD deficiency was performed. Transthoracic Doppler echocardiography was performed during steady-state at each patient's initial visit and yearly thereafter. PHT was defined as a tricuspid regurgitant jet velocity (TRV) > or =2.5 m/sec. RESULTS: Twenty-seven patients (31.8%) were found to have PHTN. They had significantly higher LDH levels (P = 0.008) and MCV (P = 0.024). There was a higher percentage of patients on hydroxyurea in the group with PHTN (78% vs. 50%, P = 0.015). Furthermore, five children, mean age 9.8 years (range, 6-13 years), with initially normal TRV developed PHTN while on hydroxyurea for at least 3 years, at a mean dose of 19.2 mg/kg/day (range, 14-24). PHTN clustered in families and was found in all members with SCD in 7 of the 21 families studied; they contributed 16 of the 27 patients with PHTN. None of the 21 patients with PHTN were G6PD deficient compared to 4 of 36 without PHTN. CONCLUSIONS: PHTN was common, associated with increased hemolysis but not G6PD deficiency, and clustered in families. Moreover, PHTN developed despite hydroxyurea therapy in five patients.

Effect of chronic hypoxia on leptin, insulin, adiponectin, and ghrelin.

The endocrine system plays an important role in the adaptation to hypoxia. The aim of this study was to assess the effect of chronic hypoxia on insulin, adiponectin, leptin, and ghrelin levels in a neonatal animal model. Sprague-Dawley rats were placed in a normobaric hypoxic environment at birth. Controls remained in room air. Rats were killed at 2 and 8 weeks of life. Insulin, adiponectin, leptin, and ghrelin were measured. At 2 weeks of life, there was no significant difference in insulin, adiponectin, and leptin levels between the hypoxic and control rats. The only statistically significant difference was found in ghrelin levels, which were lower in the hypoxic group (3.19 +/- 3.35 vs 24.52 +/- 5.09 pg/mL; P < .05). At 8 weeks of life, insulin was significantly higher in the hypoxic group (0.72 +/- 0.14 vs 0.44 +/- 0.26 ng/mL; P < .05) and adiponectin was significantly lower (1257.5 +/- 789.5 vs 7817.3 +/- 8453.7 ng/mL; P < .05). Leptin and ghrelin did not show significant difference in this age group, but leptin level per body weight was higher in the hypoxic group. Finally, we conclude that 2 weeks of continuous neonatal hypoxic exposure leads to a decrease in plasma ghrelin only with no significant change in insulin, adiponectin, and leptin and that 8 weeks of hypoxia leads to a decrease in adiponectin with an increase in insulin despite a significant decrease in weight.

Apoptosis and the activity of ceramide, Bax and Bcl-2 in the lungs of neonatal rats exposed to limited and prolonged hyperoxia.

BACKGROUND: The aim of the study is to examine the effect of limited and prolonged hyperoxia on neonatal rat lung. This is done by examining the morphologic changes of apoptosis, the expression of ceramide, an important mediator of apoptosis, the expression of inflammatory mediators represented by IL-1beta and the expression of 2 proto-oncogenes that appear to modulate apoptosis (Bax and Bcl-2). METHODS: Newborn rats were placed in chambers containing room air or oxygen above 90% for 7 days. The rats were sacrificed at 3, 7 or 14 days and their lungs removed. Sections were fixed, subjected to TUNEL, Hoechst, and E-Cadherin Staining. Sections were also incubated with anti-Bcl-2 and anti-Bax antisera. Bcl-2 and Bax were quantitated by immunohistochemistry. Lipids were extracted, and ceramide measured through a modified diacylglycerol kinase assay. RT-PCR was utilized to assess IL-1beta expression. RESULTS: TUNEL staining showed significant apoptosis in the hyperoxia-exposed lungs at 3 days only. Co-staining of the apoptotic cells with Hoechst, and E-Cadherin indicated that apoptotic cells were mainly epithelial cells. The expression of Bax and ceramide was significantly higher in the hyperoxia-exposed lungs at 3 and 14 days of age, but not at 7 days. Bcl-2 was significantly elevated in the hyperoxia-exposed lungs at 3 and 14 days. IL-1beta expression was significantly increased at 14 days. CONCLUSION: Exposure of neonatal rat lung to hyperoxia results in early apoptosis documented by TUNEL assay. The early rise in Bax and ceramide appears to overcome the anti-apoptotic activity of Bcl-2. Further exposure did not result in late apoptotic changes. This suggests that apoptotic response to hyperoxia is time sensitive. Prolonged hyperoxia results in acute lung injury and the shifting balance of ceramide, Bax and Bcl-2 may be related to the evolution of the inflammatory process.

Regulation of the sphingolipid signaling pathways in the growing and hypoxic rat heart.

Sphingolipids (SLs) have a biomodulatory role in physiological as well as pathological cardiovascular conditions. This study aims to assess the variation of SL mediators and metabolizing enzymes in the growing and hypoxic rat heart. Sprague-Dawley rats were placed in a hypoxic environment at birth. Control animals remained in room air. In control animals, activities of acidic-sphingomyelinase (A-SMase), sphingomyelin synthase (SMS), glucosylceramide synthase (GCS), and ceramidase decreased with age in both ventricles whereas activity of neutral-sphingomyelinase (N-SMase) increased with age. Hypoxic RV mass was 171 and 229% that of controls, at 4 and 8 weeks, respectively. This was accompanied by an increase in RV myocardial ceramide synthesis, consumption and breakdown, with a net effect of suppression of ceramide accumulation and increase in diacylglycerol (DAG) concentration. In addition, significant increase in activities of: A-SMase by 26 and 29%, SMS by 108 and 40%, and ceramidase by 66 and 35%, in the hypoxic RV rats as compared to controls, was noted at 4 and 8 weeks of age, respectively. Sphingolipids and their regulating enzymes appear to play a role in adaptive responses to chronic hypoxia in the neonatal rat heart.