Absent Left Main Coronary Artery with Variation in the Origin of its Branches in a South African Population

Abstract

Coronary artery anomalies are traditionally classified into anomalies of origin, course and termination. One of the anomalies of origin is absence of the left main coronary artery (LMCA), where the left anterior descending (LAD), the circumflex (Cx) and the ramus medianus (RM) (when present) arteries originate directly from the left aortic sinus. The study aimed to document the prevalence of absent LMCA, discuss its possible embryogenesis and clinical relevance. A review of 407 coronary angiograms performed by cardiologists of three private hospitals in the eThekwini Municipality area of KwaZulu-Natal, South Africa, was performed. The LMCA was absent in 9.6% (39/407) of the coronary angiograms. The LAD and Cx arteries originated directly from the left aortic sinus with a single ostium in 8.6% (35/407) and separate ostia in 1% (4/407) of the angiograms. In four of the angiograms with absent LMCA, a RM artery was recorded originating directly from the left aortic sinus in addition to the LAD and the Cx arteries. Angiographic detection of the anomalies of the coronary arteries is essential in the determination of the significance of such findings and their management.

Anatomic study of the morphology of the right and left coronary arteries

“…In these cases, left dominance was observed in all hearts and this variation was observed in more females (83.3%) than males (16.6%). This was lower than Ajayi et al [1], who found 20.5% of hearts presenting a split RCA with and an absent LCA. This study found left dominance to be more prevalent in the presence of a double or split RCA (85.7%).…”

“…Bogers et al [8] showed that coronary vessels develop by ingrowth towards their orifices on the ascending aorta which differs from the previous assumption that coronary arteries are formed by outgrowths from the aorta and the systemic venous sinus, respectively. Ajayi et al [1] suggested that the high prevalence of split RCA in hearts with absent LCA may be due to the occurrence of the fast ingrowth of the primitive coronary vascular network in both the left and right coronary vascular tree. The branches of the RCA may have joined to form a single trunk while approaching the right coronary ostium due to fast ingrowth in such hearts.…”

Characterization of coronary arteries in Giant Anteater (Myrmecophaga tridactyla: Myrmecophagidae)

“…In 16.66% of the cases, this vessel did not present its origin from the aorta, but only its branches, a fact that has not been reported in literature. It was not observed absence of the left coronary artery, as reported in Syrian hamsters (Durán et al, 2006) and humans (Ajayi et al, 2015), or even the artery presenting itself duplicated (Kareem et al, 2014).…”

“…The right and left coronary arteries emerge from the aorta, each one presenting a single coronary ostium (Schummer et al, 1981;Ghoshal and Getty, 1986;Ghoshal, 1986, Valentina et al 2003and Oliveira et al, 2013. There are cases in calves and humans with only one coronary artery being responsible for the whole heart's irrigation, presenting only one ostium from the aorta (Cervený andKaman, 1963 andKoizumi et al, 2000) and in the Syrian Hamster and man, where the left coronary artery is absent, presenting only the branches originating from the aorta (Durán et al, 2006 andAjayi et al, 2015).…”

Morphologic Relationship Between the Coronary Arteries During Fetal Development

“…This may suggest that the LCA grows faster than the RCA during fetal development. Ajayi et al (2015), reported that 20.5 % of the patients with absent LCA had splitting of the RCA and suggested that in such patients during development of the coronary arteries there is fast ingrowth of the primitive coronary vascular network in both the left and right coronary vascular tree. Int.…”