1. Abstract Tetralogy of Fallot (TOF) is the most common cyanotic congenital heart disease. Its association with Pulmonary Atresia is considered to be the most severe form, the diagnosis of which plays an important role in determination of the treatment protocol. In such cases, systemic vascular channels called Major Aortopulmonary Collateral Arteries (MAPCA’s) develop from aorta and its major branches to supply and maintain the pulmonary circulation. Such patients commonly undergo a Cardiac CT as an imperative pre-operative investigation for detailed information of these collaterals which helps plan further management. Here, we present a Case Report of an adult female patient with Pentalogy of Fallot wherein, a Cardiac CT showed the presence of dilated coronary-to-pulmonary collateral circulation. i.e. CAPA apart from the normally visualized MAPCA’s, an extremely rare occurrence.
2. Introduction3. Case Report A 21-year-old female patient was referred to our institute for evaluation and treatment of cyanotic congenital heart disease. She currently complained of long-standing effort intolerance, palpitations and dyspnoea (New York Heart Association Class III). On examination, she was of average build with grade III clubbing and no cyanosis at present. Her pulse rate was 92/min with blood pressure of 120/76 mm Hg. The cardiovascular system examination revealed normal S1/S2 and a continuous murmur best heard in the right parasternal area over the third intercostal space. The baseline systemic arterial oxygen saturation (SaO2) was 87%. She had a past history of cyanotic spells at birth with multiple similar on and off episodes upto 6 months of age. Her chest topograph showed mild cardiomegaly with signs of dilated right atrium, boot shaped heart, large aorta, and oligemic lung fields (Figure 1). Tetralogy of Fallot (TOF) with pulmonary atresia is a complex congenital heart disease with an incidence of 4.2-7 per 100,000 live births [1-3]. When TOF is associated with presence of an Atrial Septal Defect (ASD) or Patent Ductus Arteriosus (PDA), it is classified as a Pentalogy of Fallot. In these patients, usually, Major Aorto-Pulmonary Collateral Arteries (MAPCA’s) develop from descending thoracic aorta at the level of carina and abdominal aorta and its branches to help maintain the pulmonary blood flow and decrease the risk of pulmonary infarction. The presence of such collaterals is routinely detected on a Cardiac CT which forms the main pre-operative investigation in these patients. However, the presence of a collateral from the coronary artery to the pulmonary artery referred to as Coronary Artery–Pulmonary Artery Collateral (CAPA) or Coronary–Pulmo
3. Case Report A 21-year-old female patient was referred to our institute for evaluation and treatment of cyanotic congenital heart disease. She currently complained of long-standing effort intolerance, palpitations and dyspnoea (New York Heart Association Class III). On examination, she was of average build with grade III clubbing and no cyanosis at present. Her pulse rate was 92/min with blood pressure of 120/76 mm Hg. The cardiovascular system examination revealed normal S1/S2 and a continuous murmur best heard in the right parasternal area over the third intercostal space. The baseline systemic arterial oxygen saturation (SaO2) was 87%. She had a past history of cyanotic spells at birth with multiple similar on and off episodes upto 6 months of age. Her chest topograph showed mild cardiomegaly with signs of dilated right atrium, boot shaped heart, large aorta, and oligemic lung fields (Figure 1).
4. Discussion Tetralogy of Fallot (TOF) is the most common cyanotic congenital heart disease with an estimated worldwide prevalence of 3 cases per 10,000 live births [4]. It is a conotruncal defect which occurs due to an anterior malalignment of the infundibular septum which is responsible for the four main components [5] (Figure 6). a). Ventricular Septal Defect (VSD) b). Pulmonary Infundibular Stenosis c). Over-riding of aorta. d). Right ventricular hypertrophy. The association of TOF with an Atrial Septal Defect (ASD) or Patent Ductus Arteriosus (PDA) classifies it as a Pentalogy of Fallot, as was visualized in this case. The clinical presentation of these patients as well as their prognosis predominantly depends on the degree of obstruction to pulmonary blood flow, whether hypoplastic, severely stenotic or completely atretic pulmonary valve and pulmonary arteries [6]. In such cases Multiple Abnormal Vascular Channels (MAPCA’s) [7, 8] develop from the thoracic aorta, abdominal aorta, subclavian artery, bronchial and intercostal arteries which are connected to the pulmonary arterial vasculature distally, thereby maintaining the pulmonary blood flow and reducing the chances of pulmonary infarction. However, in rare cases, coronary arteries, i.e. Right Coronary Artery (RCA), Left Main Coronary Artery (LMCA) or its branches Left Anterior Descending artery (LAD) and Left Circumflex artery (LCX) can be a source of pulmonary blood flow [9]. Amin et al. [10] hypothesized that a communication between the coronary and pulmonary artery is physiologically and embryologically more similar to a ductus arteriosus than to systemic–pulmonary collaterals as this communicates in an antegrade fashion with the central pulmonary arteries. Sometimes a coronary to pulmonary artery communication with sufficient calibre can become the primary source of pulmonary blood flow in patients with PA/VSD.
5. Conclusion Figure 6: Schematic diagram showing components of Tetralogy of Fallot of various systemic–pulmonary as well as coronary-pulmonary Congenital cardiac diseases belong to a complex group of diseases and knowledge of their myriad of presentations has an important bearing on the overall physical and mental health of patients. With the advent of newer generation MDCT scanners, presence collaterals can be delineated in a non-invasive manner with the added advantage of detection of extracardiac anomalies as well, thus obviating the need for invasive procedures such as catheter angiography
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Anagha R. Joshi. A Road from Coronary to Pulmonary: A Rare Imaging Presentation. Annals of Clinical and Medical Case Reports 2022