Single coronary artery anomaly: classification and evaluation using multidetector computed tomography and magnetic resonance angiography

Applicability of the Leiden Convention and the Lipton Classification in Patients with a Single Coronary Artery in the Setting of Congenital Heart Disease

In single coronary artery (SCA) anatomy, all coronary tributaries arise from a single ostium, providing perfusion to the entire myocardium. Coronary classification systems can facilitate the description of SCA anatomy. Aim: Evaluation of the applicability of Lipton classification and the Leiden Convention coronary coding system in SCA. Methods: All patients (n = 6209) who underwent computed tomography (CT) scanning between 2014 and 2018 were retrospectively examined for the presence of SCA and classified, according to Lipton classification and the Leiden Convention coronary coding system. Results: The prevalence of SCA was 0.51% (32/6209). Twenty-eight patients (87.5%) had coexisting congenital heart disease (CHD), most frequently pulmonary atresia (9/32, 28.1%). Ten patients (10/32, 31.25%) could not be classified with either the Leiden Convention or Lipton classification (pulmonary atresia n = 9, common arterial trunk (CAT) n = 1). In one case with CAT, Lipton classification, but not the Leiden Convention, could be applied. In two cases with the transposition of the great arteries and in two cases of double outlet right ventricle, the Leiden Convention, but not the Lipton classification, could be applied. Conclusions: Both classifications are useful to detail information about SCA. As Lipton classification was not developed for structural heart disease cases, in complex CHD with abnormal position of the great arteries, the Leiden Convention is better applicable. The use of both systems is limited in pulmonary atresia. In this scenario, it is better to provide a precise description of the coronary origin and associated characteristics that might affect treatment and prognosis.

Prevalence and Anatomic Characteristics of Single Coronary Artery Diagnosed by Computed Tomography Angiography

Single coronary artery (SCA) is a rare congenital anomaly. We assessed the prevalence and anatomic characteristics of SCA diagnosed with coronary computed tomography angiography and compared the dimensions of the proximal SCA trunk with a reference group of 199 subjects with normal coronary arteries. We screened 30,230 patients who underwent coronary computed tomography angiography from 2008 to 2018 to identify 17 with SCA (age 55 ± 19.0 years, 8 men [47%]). The prevalence of SCA was 0.056%. SCA originated from the right sinus of Valsalva in 11 patients (65%) and from the left sinus of Valsalva in 6 subjects. According to Lipton's classification, the 17 SCAs were L1 (n = 5, 29%), L2-A (n = 1, 6%), R2-A (n = 2, 12%), R2-B (n = 6, 35%), R2-P (n = 2, 12%), and R3 (n = 1, 6%). (Lipton's classification consists of 3 groups and the division is based on the site of origin of SCA ["R" - right, "L" - left sinus of Valsalva] and its anatomical course relating to the ascending aorta and pulmonary trunk ["A" - anterior to the pulmonary trunk, "B" - between the aorta and pulmonary trunk, "P" - posterior to the aorta].) As compared with the reference group, SCA patients had shorter proximal trunks (5.0 ± 3.6 mm vs 8.6 ± 4.8 mm, p = 0.0012). The lumen area (LA) and lumen diameter of the proximal trunk in patients with SCA were larger than the LA and lumen diameter of the left main coronary artery from the reference group (49.5 ± 18.0 mm2 vs 21.3 ± 6.5 mm2, p <0.0001, and 7.8 ± 1.6 mm vs 5.1 ± 0.75 mm, p <0.0001, respectively). Moreover, the LA of the proximal SCA trunk was larger than the sum of respective measurement performed in left main coronary artery and proximal right coronary artery segments in the control group (49.5 ± 18.0 mm2 vs 34.0 ± 7.9mm2, p = 0.0001). In conclusion, the incidence of SCA is very low; but this condition is associated with significant enlargement of the proximal vessel segment.

Report on a rare single coronary artery anomaly: Need for comprehensive investigations

Single coronary artery anomaly (SCAA) is a very rare disorder with an incidence of about 0.024%–0.066% which presents with the diverse feature but is mostly asymptomatic. It has found to be one of the pathological states to cause sudden death. We report a case of R-III type of SCAA as classified by Lipton et al. which is only about 15% of all the cases of SCAA which makes it even rarer. Hypoxic environment is thought to be an important cause for the development of such anomalies which gives us clues to determine the predisposing factors to be ruled out in patient's history. Coronary angiography is the key toward definitive diagnosis which can be later supported by computed tomography scan and determination of its subtypes. Depending on the findings and physical state of the patient, medical or surgical treatment can be defined but only after correct diagnosis by comprehensive investigations.

Coronary Artery Anomalies in Animals

Coronary artery anomalies represent a disease spectrum from incidental to life-threatening. Anomalies of coronary artery origin and course are well-recognized in human medicine, but have received limited attention in veterinary medicine. Coronary artery anomalies are best described in the dog, hamster, and cow though reports also exist in the horse and pig. The most well-known anomaly in veterinary medicine is anomalous coronary artery origin with a prepulmonary course in dogs, which limits treatment of pulmonary valve stenosis. A categorization scheme for coronary artery anomalies in animals is suggested, dividing these anomalies into those of major or minor clinical significance. A review of coronary artery development, anatomy, and reported anomalies in domesticated species is provided and four novel canine examples of anomalous coronary artery origin are described: an English bulldog with single left coronary ostium and a retroaortic right coronary artery; an English bulldog with single right coronary ostium and transseptal left coronary artery; an English bulldog with single right coronary ostium and absent left coronary artery with a prepulmonary paraconal interventricular branch and an interarterial circumflex branch; and a mixed-breed dog with tetralogy of Fallot and anomalous origin of all coronary branches from the brachiocephalic trunk. Coronary arterial fistulae are also described including a coronary cameral fistula in a llama cria and an English bulldog with coronary artery aneurysm and anomalous shunting vessels from the right coronary artery to the pulmonary trunk. These examples are provided with the intent to raise awareness and improve understanding of such defects.

A Rare Case of Single Coronary Artery with Atherosclerotic Lesions Arising from the Right Sinus of Valsalva

Context:

Congenital coronary anomalies, including anomalous origin, distribution, intercoronary communications, and coronary fistulae occur at a rate of approximately 1% in the general population and are the most incidental findings.

Case Report:

A 49-year-old male patient presented to the emergency department with exercise-induced dyspnea and atypical angina pectoris. Coronary angiography (CAG) and contrast-enhanced 320-slice multidetector cardiac computed tomography with subsequent three-dimensional reconstructions revealed a single coronary artery (SCA) arising from the right sinus of Valsalva with a proximal branch giving rise to the left anterior descending coronary artery. The left anterior descending coronary artery shows severe atherosclerotic lesions and it is occluded afterwards. Adenosine stress perfusion cardiac magnetic resonance imaging (MRI) revealed a stress myocardial ischemia at the anterior wall without signs of fibrosis, scar, or necrosis.

Conclusion:

We present an extremely rare case of a SCA, with the solitary vessel arising from the right sinus of Valsalva. In our patient's case, the atherosclerotic lesions and occlusion in the branch supplying the anterior wall were considered eligible for neither percutaneous intervention nor bypass graft surgery.

A Novel TBX1 Loss-of-Function Mutation Associated with Congenital Heart Disease

Congenital heart disease (CHD) is the most prevalent type of birth defect in humans and is the leading non-infectious cause of infant death worldwide. There is a growing body of evidence demonstrating that genetic defects play an important role in the pathogenesis of CHD. However, CHD is a genetically heterogeneous disease and the genetic basis underpinning CHD in an overwhelming majority of patients remains unclear. In this study, the coding exons and splice junction sites of the TBX1 gene, which encodes a T-box homeodomain transcription factor essential for proper cardiovascular morphogenesis, were sequenced in 230 unrelated children with CHD. The available family members of the index patient carrying an identified mutation and 200 unrelated ethnically matched healthy individuals used as controls were subsequently genotyped for TBX1. The functional effect of the TBX1 mutation was predicted by online program MutationTaster and characterized by using a dual-luciferase reporter assay system. As a result, a novel heterozygous TBX1 mutation, p.Q277X, was identified in an index patient with double outlet right ventricle (DORV) and ventricular septal defect (VSD). Genetic analysis of the proband's available relatives showed that the mutation co-segregated with CHD transmitted in an autosomal dominant pattern with complete penetrance. The nonsense mutation, which was absent in 400 control chromosomes, altered the amino acid that was completely conserved evolutionarily across species and was predicted to be disease-causing by MutationTaster. Biochemical analysis revealed that Q277X-mutant TBX1 lost transcriptional activating function when compared with its wild-type counterpart. This study firstly associates TBX1 loss-of-function mutation with enhanced susceptibility to DORV and VSD in humans, which provides novel insight into the molecular mechanism underlying CHD and suggests potential implications for the development of new preventive and therapeutic strategies for CHD.