CARDIOVASCULAR JOURNAL OF AFRICA • Volume 35, No 2, May – August 2024 AFRICA 127 Coronary artery bypass grafting in a patient with situs inversus totalis Taha Okan, Caner Topaloglu, Orhan Kucuk, Selen Bayraktaroglu, Naim Ceylan Abstract Situs inversus totalis (SIT) describes a complete mirror image of the visceral organs in the thoracic and abdominal cavities. Dextrocardia, in combination with SIT, is a rare congenital anomaly with a frequency of 1:10 000, and coronary heart disease may occur with a similar frequency and manifestation as in the general population. Coronary computed tomography (CT) angiography is useful for accurately assessing the coronary artery origin and position for preprocedural planning of difficult coronary artery catheterisation in SIT. In this case, invasive coronary angiography (ICA) was performed from the same angle but on the opposite side compared to standard angiography. With the use of volume-rendered three-dimensional and curved reformatted images reconstructed from coronary CT angiography, the advancement of guidewires and catheters during ICA as well as the planning of surgical procedures can be performed more safely. Keywords: situs inversus totalis, dextrocardia, coronary computed tomography angiography, invasive coronary angiography, coronary artery bypass graft, coronary artery disease Submitted 22/6/23, accepted 5/10/23 Published online 20/10/23 Cardiovasc J Afr 2024; 35: 127–130 www.cvja.co.za DOI: 10.5830/CVJA-2023-051 Case report A 73-year-old Caucasian male presented with chest pain. His family history was strongly positive for coronary heart disease. The physical examination unveiled a chest wall deformity known as pectus excavatum. Electrocardiography results exhibited a gradual decline in R-wave amplitude from leads V1 to V6, which is indicative of dextrocardia. Transthoracic echocardiography confirmed the presence of dextrocardia. A contrast-enhanced cardiac computerised tomography (CT) examination was performed on a 128-slice single-source scanner (Somatom Go Top; Siemens Healthcare, Forchheim, Germany). CT examination revealed a situs inversus totalis (SIT) anomaly (Figs 1, 2). Coronary CT angiography (CCTA) showed a mixed plaque in the distal left main coronary artery (LMCA), extending to the proximal left anterior descending artery (LAD). Significant high-grade (> 90%) stenosis due to a mixed plaque was detected in the proximal LAD. Invasive coronary angiography (ICA) was performed from the same angle but the opposite side compared to standard angiography, with shots taken from the left instead of the classical right position, and vice versa. During the procedure, 90% stenosis was observed in the distal part of the LMCA, and 95% stenosis was identified in the proximal part of both the LAD and the left circumflex artery (LCx) (Fig. 3). Coronary artery bypass graft (CABG) was recommended to the patient. The surgeon could not use the right and left internal mammarian arteries because of the pectus excavatum deformity, and performed CABG with full venous grafts. Saphenous grafts originated from the aorta at the midline and extended towards the right side due to the presence of coronary arteries located on the right side, which is opposite to their usual anatomical position (Fig. 4). Discussion Situs refers to the position of the visceral organs in the thoracic and abdominal cavities. Situs solitus describes the normal anatomical positions of cardiac structures and thoracoabdominal organs. In SIT, there is a complete mirror-image arrangement with normal atrioventricular and ventriculoarterial connections that result in normal circulation. The morphological left atrium is on the right and the morphological right atrium is on the left. The left-sided lung is trilobed with an eparterial bronchus, whereas the right-sided lung is bilobed with a hyparterial bronchus. The liver is located left of the midline, and the stomach and spleen are on the right.1,2 Dextrocardia in combination with SIT is a rare congenital anomaly with a frequency of 1:10 000. Whereas cardiac abnormalities associated with isolated dextrocardia occur frequently, dextrocardia with SIT is rarely associated with congenital heart defects, with an incidence ranging from two to 10%.3 In patients with dextrocardia as a part of SIT, coronary heart disease may occur with a similar frequency and manifestation as in the general population.4 The high negative predictive value of normal CCTA images can effectively exclude significant coronary artery disease (CAD), thereby avoiding the need for further imaging tests and reducing the need for ICA as the first-line investigation in patients with low to intermediate risk of CAD.5 CCTA is superior to ICA in evaluating coronary artery anomalies because it gives a better anatomical depiction of the coronary arteries and more clearly shows anomalies in their origin, course and termination. CCTA is also useful for accurately assessing coronary artery origins, Cardiology Department, Kardiya Medical Center, Izmir, Turkey Taha Okan, MD, tahaokan@msn.com Cardiology Department, Izmir Economy University, Izmir, Turkey Caner Topaloglu, MD Radiology Department, Ege University, Izmir, Turkey Orhan Kucuk Selen Bayraktaroglu, MD Naim Ceylan, MD
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